final report e8004 - #26

of 22

Aalto University, School of Electrical Engineering Automation and Electrical Engineering (AEE) Master's Programme ELEC-E8004 Project work course Year 2019

Final Report

Project #26 Induction Heater for Melting Aluminum

Date: 31.5.2019

Yuvin Kokuhennadige Md Masum Billah

Joni-Markus Hietanen Jaakko Lind

of 22

Information page Students Yuvin Kokuhennadige Md Masum Billah Joni-Markus Hietanen Jaakko Lind Project manager Yuvin Kokuhennadige Official Instructor Dr. Floran Martin Starting date 10.1.2019 Completion date 21.5.2019 Approval The Instructor has accepted the final version of this document Date: 31.5.2019

of 22

Abstract Our project was to build an efficient and safe heating device that could melt aluminum by

electromagnetic induction. The purpose of this device is to melt aluminum cans at collection points when recycling. The heating element of our device is made of a graphite crucible and Litz wire, while the power electronics are built to provide the necessary power that can maintain a steady state temperature of more than 650℃ in the crucible. Induction from the Litz wire creates eddy currents in the crucible in order to heat up aluminum over its melting point. This induction heater can also be used for other applications of melting and heating materials within temperatures 650℃ and 900℃.

The development of the induction heating device included thermal analysis of the heating

element and circuit simulation of an inverter and a gate driver. These made us identify the necessary parameters needed to operate our device efficiently and safely. The operating frequency of our device was found to be 100 kHz. Therefore, the gate driver and the inverter were designed to work at that frequency. We were able to successfully implement a 100 kHz gate driver; however, the H-bridge was not operational at that frequency due to parasitic capacitance of the MOSFETs. The heating element was implemented according to the analytical thermal model, but it was not tested for successful operation due to the inverter not being able to deliver power to the Litz wire.

Further development of the inverter in our project to provide a high frequency output could

result in an operational device that melts aluminum. The analytical models and simulations generated during this project were an important step towards building a successful induction heating device that can melt aluminum cans in the collection stage of the recycling process.

of 22

Table of Contents

Abstract ................................................................................................................................................ 3 Table of Contents ................................................................................................................................. 4 1. Introduction .................................................................................................................................. 5 2. Objective ...................................................................................................................................... 5 3. Project plan .................................................................................................................................. 5 4. Heating Element Design .............................................................................................................. 6

4.1. Frequency Selection ............................................................................................................. 6 4.2. Wire, Insulation and Crucible Selection .............................................................................. 7 4.3. Power Transmission ............................................................................................................. 8 4.4. Analytical Results ................................................................................................................ 9

5. Inverter Design ........................................................................................................................... 10 5.1. Power Electronics .............................................................................................................. 11 5.2. Gate drivers ........................................................................................................................ 11 5.3. Implementation .................................................................................................................. 14

6. Reflection of the Project ............................................................................................................ 17 6.1. Reaching objective ............................................................................................................. 17 6.2. Timetable ........................................................................................................................... 18 6.3. Risk analysis ...................................................................................................................... 19 6.4. Project Meetings ................................................................................................................ 19 6.5. Quality management .......................................................................................................... 20

7. Discussion and Conclusions ....................................................................................................... 21 List of Appendices ............................................................................................................................. 22 References .......................................................................................................................................... 22

of 22

1. Introduction Nowadays, an efficient heating system is highly demandable due to the rapid growth in

industries. There are several heating techniques used in industry to perform heating tasks. One of the most efficient, reliable and secure heating methods used to melt metal is induction heating. Aluminum is a common metal used in variety of products in households or industries. Around the world, large amounts of aluminum cans are produced every day. Recycling aluminum cans saves energy, reduces environmental pollution and minimizes waste at landfills. Apart from that, recycling aluminum cans is a large business with large market size. Therefore, a fast and efficient heating system is highly demandable to make the recycling business more profitable.

The principle of induction heating is developed based on Faraday’s law of electromagnetic

induction. According to Faraday’s law, when an alternating current flow through a coil, it induces a magnetic field around the coil. The density of the induced field depends on the number of turns of the coil. The varying magnetic field induced by the coils flow through the metal workpiece and produces eddy currents flowing through the workpiece. Energy is lost due to eddy currents and the resistivity of the workpiece, which are dissipated as heat through the workpiece.

In induction heating systems, the higher concentrations of eddy current are preferred near

the surface of the workpiece rather than center. This phenomenon is known as the skin effect. High frequency pushes the eddy currents to flow at the surface, hence, increasing the skin effect. Furthermore, high skin effect increases the effective resistance of the workpiece and causes high heat as needed to melt the workpiece.

2. Objective Main objective of this project is to build a functional induction heater prototype, which is

capable of melting aluminum cans. Project hardware consists of four main components: a rectifier, inverter, inductor and crucible. Rectifier and crucible have been bought as full industrial packages, but inverter and inductor as well as their desired characteristics have been designed and built independently. Output for desired current and therefore temperature should be precisely controllable. Prototype should also be robust as well as easy and safe to use. Later the prototype should be able to be productized to a saleable commodity, with constant option for further product development.

The end-product can decrease volume of aluminum cans to enable more efficient shipping

or melt aluminum on junkyards to be sold as low-volume metal blocks. In the recycling business, it would make aluminum recycling less expensive and energy-intensive. However, main objective is that it will save our customers significant amount of money. Further developed end-product could also be able to melt any desired metals with melting point below of around 1200°C, after further thermodynamic calculations and implementations. In this case, our product could also be sold to jewelry stores or manufacturers for easy “tabletop foundry device”.

3. Project plan The project plan gives a relevant background and motivation for the whole project. In the

project plan the goal of the project and expected output are well defined. The electromagnetic induction is explained and the needed system for the purpose is proposed and justified. The introduction of the project plan was in terms with the project till the end, as the basic operation of the project output remained unchanged during the project. However, some changes to the initial plan were made during the project.

of 22

The project plan has well defined and scheduled phases of the project. The definitions of the project phases were relevant during the project with some changes done but the initial schedule for the completion of each phase did not match the project plan. The phases of the project with updated descriptions as well as the actual completion dates can be seen in the section 6.2 of this report. The main delays happened in the conceptualization, prototyping as well as in the implementation phases. The delays happened mainly because we needed to do some changes to our initial project idea, and this slowed down the processes. Some delays also happened because of the component deliveries.

The project plan had scheduled times for transformer implementation as well as design for a

cooling system for the coil. Later in the project, with the new project idea these components became irrelevant as they were not needed in the system. The resources that were planned on these were used for planning the implementation of the inductor made from Litz wire and the effect of graphite crucible that was not initially planned on being in the system. In order to use these new components, we needed to do more thermal modelling than initially planned.

Cost for this project was estimated in the project plan. The initial estimation for the whole

cost of the system was quite accurate. However, we needed to do some changes to the system in the implementation phase, so the total cost was higher than planned. These costs were mainly due to the changes of the power electronics.

The risk analysis of the project plan describes multiple justified risks for the whole project.

One of the biggest risks in our case was the design flaws in the project. Even with careful and well-done simulation of the whole system circuit, we ran into a problem that we couldn’t tackle in the system. The parasitic capacitances of the MOSFETs made our H-bridge not operational with the used gate driver circuitry. Because of the high switching frequency of 100 kHz the system did not work in the end. The designs of the circuits are explained in section 5 of this report.

4. Heating Element Design The main objective of the heating element design was to generate sufficient temperature for

melting aluminum. The heating element consists of a graphite crucible, fiber glass wrap insulation and Litz wire as shown in figure 1. A power supply with desired output current, voltage and frequency were required to get the proper temperature. Therefore, the design specifications for the power electronics were also determined in this section. Furthermore, the number of insulation layers were calculated to protect the Litz wire from high temperature. Finally, a thermal model was developed to ensure the temperature limit for the Litz wire and melting temperature for the aluminum.

4.1. FrequencySelection

Alternating current (AC) flows through the skin or the surface of a conductor rather than the center of a conductor. Therefore, the current density is larger near the skin or surface of the conductor. This phenomenon so-called skin effect is used in induction heating systems. Higher skin effect increases the effective resistance of the workpiece which leads to the resistive losses of the workpiece, hence, producing high heat eventually melting the aluminum. The qualitative measure of skin effect depends on the skin depth of the work piece and the frequency. At high frequency, the skin depth becomes smaller, thus, the skin effect increases.

The required frequency of the current can be determined from the skin depth of an

aluminum can using the following equation

of 22

" = $2

&'((4.1)

where (is the conductivity of aluminum, ω is the angular frequency and μ is the total

permeability of the material. By solving the above equation, using the MATLAB script in Appendix 2, the switching

frequency was found to be 100 kHz.

4.2. Wire,InsulationandCrucibleSelection

The design process of the induction coil started by considering a copper tube. Later the copper tube was replaced by the Litz wire. Even though Litz wire is more expensive than a copper tube, special characteristics of Litz wire met our design requirements. A Litz wire is a special type of wire consists of multiple strands insulated from each other. This wire can carry more alternating current (AC) current by minimizing the skin effect at high frequencies. As we are using high frequency in our device, Litz wire is more suitable for our design compared to a copper tube. In addition, Litz wire currents are distributed equally among multiple strands by reducing the resistance and increasing the power transmission capability. The selected Litz wire for our device has the specifications shown in the table 1.

Table 1. Litz wire specifications.

Wire diameter 0.5 mm

Number of strands 70

Strands diameter 0.056 mm

Wire length 19.5 m

Resistance 1.75Ω

Inductance 32.8 µH

Maximum temperature limit 150 - 180℃

To protect the Litz wire from high temperatures, sufficient insulation is needed between

the crucible and the Litz wire. Fiberglass wrap was used as insulation because of its high temperature resistant capability. The width and thickness of the used fiberglass wrap are 50 mm and 1.1 mm, respectively. Maximum temperature limit of fiberglass wrap is 1200℃, which was sufficient for our design. By verifying with the thermal model, a total of 19 layers of insulation was used in our design.

The graphite crucible was used to hold the melting aluminum. We chose a graphite

crucible because of the high melting point of graphite; thus, it can withstand the high temperatures. The specifications of the used graphite crucible are given in table 2.

Table 2. Graphite crucible specifications.

Inner diameter 46.19 mm

Outer diameter 70.57 mm

Height 113 mm

Maximum temperature limit 2500 ℃

of 22

Figure 1. Final design of the induction heating element.

4.3. PowerTransmission

Eddy currents are responsible for transmitting power to the graphite crucible. Therefore, solving for the eddy currents was essential to calculate the transmitting power. As shown in Appendix 1, the Maxwell equations were solved and the 1D analytic solution of the Bessel function was used to find the eddy currents. The amount of power transmitted to the graphite crucible was calculated using the following equation

2(3) =456678888888. 456678888888∗

2( (4.2)

where 456678888888∗ is the conjugate of 456678888888 and ( is the conductivity of the material. Current through the inductor coil was estimated using Ampere’s law,

:; =<;=>;

(4.3)

where <; is the magnetic field strength of the coil, L is the length of the wire and >; is the number of turns. The MATLAB script in the Appendix 2 was used to calculate the transmitted power and other parameters for the design are given in the following table.

Table 3. Design parameters and transmitted power.

Supply current 2.1 A

Required voltage 43.3 V

Number of turns 55

Total transmitted power 60.1 W

of 22

4.4. AnalyticalResults

A thermal model of the heating element was developed to ensure that the temperature at the Litz wire is within the specified limit while sufficient melting temperature is at the aluminum can. The number of insulation layers required to save the Litz wire was determined by this thermal analysis. As heat transfers from a higher temperature to a lower temperature, we modeled that heat transfers from the aluminum can to the Litz wire. In this model, heat transfer to the air (convection) is also taken into account.

Figure 2. Thermal model of the heating element.

The thermal resistance of the heating element in the radial direction is calculated using

the equation

@AB =ln(3E3F

)

2GHI (4.4)

where 3E and 3Fis the outer and inner diameter of the elements, H is the thermal conductivity of the elements and I is the length of the elements. The thermal resistance due to convection is calculated using the equation

@JKL =1MN(4.5)

where M is the convection coefficient and N is the cross sectional area.

The thermal model was solved analytically for three different temperature points, at the

Litz wire, at the graphite crucible and at the aluminum can. The MATLAB script in Appendix 3 was used to calculate the thermal resistances, convection resistances, losses in the elements and the temperatures at different points. Analytical results of the temperatures at the three different points are shown in table 4.

Table 4. Analytical results of the heating element.

Litz wire 78℃

Graphite crucible 921℃

Aluminum can 921℃

of 22

From the analytical results, it is visible that the Litz wire temperature is within the

specified limit of 150℃ and the temperature at the aluminum can is sufficient to melt it. The experimental results are not available as tests with the heating element was not conducted due to issues with the power source which is explained in the next section.

5. Inverter Design After calculating the desired output current amplitude and frequency, it was easier to define

the preliminary needs for our inverter, as it should be able to output 14 Amperes at 100 kHz frequency to reach our target temperatures. Inverter consist of four power MOSFETs and their control circuitry, the gate drivers. Power MOSFETs are connected in a H-bridge, with inductor as its load (Figure 3). The H-bridge is the easiest way for supplying alternating current to the load, which is needed for induction. Power electronics had rather low voltage requirements, as the need current and switching frequency were high. The inverter is supplied with a rectifier, which was purchased as a commercial package. It feeds the H-bridge with constant 48V voltage and maximum 20A of current.

Figure 3. Simplified schematic of the inverter design. MOSFETs are connected in an H-bridge with inductor as a load. Resistor Rs represents inductor wire resistance.

of 22

Figure 4. Simulated output current and output voltage fed to the inductor.

5.1. PowerElectronics

For main power electronic components, we chose IXYS Polar3 HyperFET Power MOSFETs (IXFH60N50P3), with current rating of 60A, voltage rating of 500V and power dissipation of 1040W. This particular MOSFET was suitable, due to its high-power durability, documented use of high switching frequency as well as availability and price. Also, current and voltage ratings were adequate at least according to simulated values and all of their potential transients.

5.2. Gatedrivers

We designed and built our own gate drivers for supplying the power electronics. Preliminary needs included sufficient and controllable fluctuating input current to the load, with constant switching frequency of 100kHz. Values for frequency as well as current were calculated by hand, and afterwards simulated with different simulation tools to ensure sufficient temperature on the crucible and our workpiece. Output current is controlled by adjusting the relative duty cycle of the gate pulses via a potentiometer, in order to reach the desirable temperature at the crucible.

Figure 5. PLECS simulation of the gate drivers.

of 22

Design of the gate driver starts with an oscillator. We chose a clock crystal oscillator (OV-0100-C7) that derives 100 kHz output at 5 V amplitude, which was perfect for our purposes. After this, the oscillating signal was divided into two. Second signal was delayed for 5µs to gain a perfect phase shift between the two gate signals of MOSFETs in the same leg. Delay circuit we chose for this purpose was LTC6994-2. Next, the two square-wave signals were transformed into triangular wave by adding a few capacitors and resistors. These triangular waves function as our carrier signal for generating PWM.

In order to achieve the desired controllability, we chose to control the MOSFET gate

inputs manually, using a potentiometer and simple voltage division technique. Via the potentiometer, we could increase and decrease a fixed DC-voltage value, which is compared to the triangular waves using comparators (LM339). At the comparator outputs, we have two convergent gate pulses with perfect constant delay compared to each other. These pulses were then amplified with simple bipolar transistors (2N2907A) and fed to optocouplers (HCPL-4200), in order to have the drivers galvanically isolated from the power electronics. Also, this method gives us steady gate pulses with desired amplitude, which in this case was set to 15V. Simulations are presented on figures 3 and 4. On the gate driver subsystem, oscillator and transformation to triangular wave have been implemented on a simpler triangular wave block for simplicity, but real circuit is presented on the schematic (Figure 5).

Major issues with this approach are that the gate pulses for upper and lower MOSFETs

can’t overlap, as a short circuit through them would quickly destroy the components. Other issue to be considered is that the changes for supplying the components have to be fulfilled slowly enough, since fast changes would result to high current and voltage transients, also capable of burning our power electronics.

First issue was taken into account at the voltage division. We chose the resistor values in

such manner, that the minimum DC-level achievable by the resistance change with the potentiometer would correspond to around 45% of pulses duty cycle. Therefore, the two pulses would have enough switching time on maximum duty cycle conditions, and they would never overlap. Also, if the DC-level would exceed the carrier triangular waves amplitude, comparator would not give an output and gate pulses would be cut off (Figures 6 - 8).

Figure 6. Waveform of maximum achievable duty cycle. On the left are the two carrier signals, and on the

right the gate signals. Gate signals never overlap.

of 22

Figure 7. Waveform of decreased duty cycle.

Figure 8. Waveform of lower duty cycle. As DC-reference (red on the left figure) is increased over the

carrier waves amplitude, gate pulses will stop.

Second issue can be solved by careful increase of pulse widths while testing the inverter. Since the control is done manually, the individual lowering of the reference voltage should be done so slowly and steadily until the desired condition has been reached. This prevents the most destructive power surges from occurring. It is a crucial issue to be noted with such high frequencies.

Simulations were carried out with Plecs and LTSpice-tools both for power electronics

and individual electronic circuits. It is notable, that all of the real-life phenomena considering the switching of power electronics cannot be taken into account with these simulation tools at such high frequencies.

of 22

Figure 9. Schematic of the gate driver circuitry.

5.3. Implementation

Implementation of gate-driver circuitry was not as simple and straightforward as one could expect. Especially the component selection and their configurations were at times really difficult, since the switching frequency of 100kHz generates a lot of undesirable phenomena, and most of the basic components are not made for such frequencies. Also, some of the components were really small by size, so their connection was challenging in general. Debugging the different phases of the previously described schematic was time consuming, but in the end the gate drivers functioned nearly as they were specified. However, the inverter could not work with the complete H-bridge, as discussed below.

After previously designed gate drivers were implemented (Figure 10), gate signals were

close to perfect. Amplitude, controllability and phase of the generated PWM worked perfectly. In comparison for simulated gate signal values, measured values derived from an oscilloscope are visible on figures 11 to 13. However, after connecting this gate driver to our power electronics, the signal became heavily distorted and noisy.

of 22

Figure 10. Implemented gate drivers on a circuit board.

Figure 11. Measured gate driver signals at their maximum duty cycle. On the upper part, one of the carrier

waves is visible alongside the controllable dc-value.

of 22

Figure 12. Measured gate driver signals with lower duty cycle.

Figure 13. Measured gate driver signals with low duty cycle. If DC-value exceeds the amplitude of carrier

signal, pulses are stopped.

Distortion of the signal was caused by the parasitic capacitances of the chosen MOSFET and was really significant due to high switching frequency. This issue was tackled with a bootstrap-circuit with a transistor totem pole. Bootstrap circuit allows the operating point of the transistor to be altered, by controlling the input impedance of an amplifier. Transistor totem pole is used to control the ground level on our H-bridge, as on the upper MOSFETs, the source of the transistor is not always connected to ground. With a totem pole, we are able to control the upper MOSFETs with our signal, since the source is virtually grounded and the gate signal amplitude between gate and source sufficient for our needs. Together they were implemented in order to solve our issues caused by the parasitic capacitances.

of 22

Figure 14. Schematic of the push-pull totem pole with a bootstrap, which was implemented after the

optocouplers on previous schematic (Figure 9).

Afterwards, the gate signals were significantly better than the distorted ones. With one discrete MOSFET we were able to output current in sinusoidal form at amplitude of 2 Amps, but with a full H-bridge we were not able to get good results. This current heated up the crucible a bit but did not reach temperatures needed for melting aluminum.

6. Reflection of the Project 6.1. Reachingobjective

The expected output of the project was not completed as we were not able to get our power electronics working as designed. The expected output of the project was to melt aluminum using electromagnetic induction. The goal was clearly not met because we were not able to provide the induction coil with the needed current with our desired switching frequency. The objective was to create two subsystems that would work together in the end. We were not able to test the heating element subsystem as it was designed to work with the parameters provided by our power electronics.

The simulations for the power electronics and heating element were created carefully.

The simulations were used to define the needed components for the subsystems. In the simulations, the objective for the project was reached. The simulation results worked together and the needed temperature for melting aluminum was reached. Even with these results, the final system did not work. The reasoning for failures is described already in this report.

The objective was remained almost the same during the whole project, but the heating

element design was changed during the design phase of the project. It was thought that the water-cooled copper induction coil would be hard to implement, so we decided to proceed the design with Litz wire and graphite crucible with fiberglass insulation between these two components. This suggestion was internal as we were discussing about the implementation of the cooling system and came up with a better solution with the help of our instructor.

of 22

6.2. Timetable

The overall project was realized as planned, however there were some delays in conceptualization and prototyping phase as our design idea changed from the initial idea we planned. Phases mentioned in the project plan were completed as shown below. It is noticeable that there were some delays in meeting the deadlines planned. However, the overall project deadlines were reviewed, and necessary precautions were taken when these delays occurred in order to make sure it does not affect the overall project.

The workload of the project was as estimated, and we each spent about 200 hours on the

project. Most of our hours towards the project was invested in the last two weeks before the gala as our subsystem completion and system integration did not go smoothly as planned and we had to spend a lot of time debugging. Therefore, it is clear that we underestimated the workload for those phases of the project when we allocated time in our project plan.

M1 Planning (Planned deadline: 4.2.2019, Completed on: 1.2.2019)

During this phase the project plan document was completed and was used as the basis for conducting duties of the project.

M2 Conceptualization (Planned deadline: 18.2.2019, Completed on: 9.3.2019)

Conceptualization was delayed due to some changes that had to be made in order to achieve our project goal. During conceptualization it was found that we would not be able to build power electronics to provide the enormous power needed when using a copper tube as the induction source. After finding this issue, a new concept was realized using litz wire and a graphite crucible.

M3 Prototyping (Planned deadline: 18.3.2019, Completed on: 12.4.2019) Prototyping was done using simulations for power electronics and using a theoretical model for the thermal design of the crucible. There were delays in this phase as a ripple of the delay in the previous phase as well as some additional delays caused by errors in our models that needed correction.

M4 Subsystem completion (Planned deadline: 15.4.2019, Completed on: 18.5.2019) The duration of this phase includes the time taken to place orders and delivery of needed material. After collecting the parts, the assembly of independent subsystems were done and then tested for their performance. Some issues with the subsystems were also realized but had to move onto the next phase since we were approaching the final deadline.

M5 System integration (Planned deadline: 6.5.2019, Completed on: 20.5.2019) Separately implemented subsystems were integrated in this phase to complete the system. Testing was conducted to make sure the heating device operates as designed. However, our system did not function as expected and caused major issues which we were not able to resolve in the time available.

M6 Final delivery (Planned deadline: 20.5.2019, Completed on: 20.5.2019) This phase was intended to demonstrate the working device to the instructor and to others who are interested. Since our device did not function, we were able to deliver a model of the device instead of a working prototype.

of 22

M7 Presentation (Planned deadline: 21.5.2019, Completed on: 21.5.2019) Poster presentation and highlight talk was done at the final gala to present our results and findings the attendees. Even though our device did not operate, we displayed analytical results and simulation results we obtained while designing the device.

M8 Project Report (Planned deadline: 31.5.2019, Completed on: 31.5.2019) This project report was completed as planned by the deadline with the available results from our project.

6.3. Riskanalysis

Design flaws are one of the common risks that were visible during the project. Errors in the models consumed a large amount of time to debug which slowed down the design process. An alternative plan and a rapid solution minimized the severity of the risk. During the project, few initial plans were changed which also affected the project timeline and delayed the process. The risk was minimized by implementing the new plan effectively.

Another risk was also noticeable during the ordering and shipping of the components.

The order placement of the components took quite a long time which delayed the process. Also, the shipping time of the components was different and some of the components took a longer time than others. The risk was tackled by starting to implement with the components that arrived first. Some of the components that were delivered did not meet the design specifications we ordered or needed. Due to time constraints we had to adjust our project parameters and dimensions to suffice the delivered components. In some occasions, we needed to reorder the components or buy from a local store which exceeded the proposed project budget.

Health hazards were also realized during the implementation phase. To make the

insulation layers we needed to cut the fiberglass wrap. During that time, we felt unexpected itching in our body because of the tiny glass components. The severity of this risk was quite low. There could have been more risks associated in the testing phases such as aluminum oxide, paint fumes and fire hazard. Since we were not able to test the design, those risks were not realized during the project.

6.4. ProjectMeetings

With our instructor we had project meetings on average every other week. Meetings were arranged in order to report our progress as well as to solve more advanced issues considering the project development. Our instructor was very supportive during this process and capable of solving quite complicated problems consistently in a manner, that supported the project works learning objectives to us. Also, on the design phase of the project, he had fresh and diverse ideas to tackle some of the development-related problems, resulting to better and more versatile end product.

Among the group, we additionally met on average once a week to report our progress on

different segments of the project and discuss the arisen questions with each other. During these meetings, our objective was to solve our issues together and keep track of the project status in general. These meetings were documented and archived for later reference. In addition, as new development proposals or issues were found, they were later carried out to instructor meetings. This method of working helped the instructor meetings to be more efficient, and therefore smoothed the whole development process.

of 22

Archives of the meeting documents were stored on a common google drive folder, which also included all of our documents considering design specifications, business aspects, technical simulations and drafts of different reports. There, they were easy to reach if necessary.

In order to make project meetings more efficient, we learned in an early stage, that if

there was a more demanding or otherwise time-consuming issue at hand, it was not worth all of our time to look as one person of the group tried to solve it. In these occasions, we usually postponed the task to occur outside the meeting or tried to solve it in the group. If solution could not be reached, then it was later brought up on the instruction meetings. Overall our efficiency during these meetings was decent.

6.5. Qualitymanagement

In our project plan the management of quality was defined for the various parts of the project. The main points were that every team member will do their tasks with best possible quality. The basic idea was that the project manager is not fully responsible for the quality. However, he was responsible for approval of each step of the project. For example, after a document was done, the project manager was the one approving it so that it could be sent to the instructor for final approval. In our project, the instructor was the one who did the final approvals and gave feedback on our work.

The quality plan was followed well when creating the documentation for the project as

well as preparing for presentations. The quality of these deliveries has been approved by the project manager and the documents were approved by the instructor as well. During the project, the documentation has achieved high quality and the presentations have also been on satisfactory level. The project manager has done a good job on supervising the quality of the team’s work.

In the integration phase the obvious quality issue was that the system did not work as

intended. Because of this issue, the wanted quality for the presentation was not achieved as we were not able to show the functionality of the whole system. We couldn’t prevent these issues even though the integration phase was planned well ahead.

There were some issues about the quality of the system. There were two main things that

would have improved the quality of the final system. During the planning phase, we did not design a PCB and a case for our power electronics. A PCB and a case would be essential for the gate driver circuitry and H-bridge as they have numerous connections that we needed to be cover and secure. The case would have also made the product more professional looking. The second quality issue was related to the graphite crucible in the heating element. We did not plan how the molten aluminum would be taken out of the crucible easily. There could have been designed a pouring mechanism that would help with the issue. Without this kind of mechanism, it was decided that the aluminum would be taken out of the crucible when it was cooled down. With these two improvements, the final product would have been safer and more user-friendly.

of 22

7. Discussion and Conclusions This project gave all members of the team a foundation in thermal modelling as we got to

learn analysis as well as solving a thermal model. We learnt this while calculating for the amount of insulation needed in the heating element to assure thermal safety of the inductor when there are high temperatures at the crucible. Finding thermal properties of the materials used and evaluating the physical dimensions of the device were important aspects of the thermal analysis. Eddy currents in the crucible was calculated using the 1D analytic solution of the Bessel function which was taught to us by our instructor. This solution gave us an idea of how complex thermal analysis can be as solving the Bessel function required very advanced knowledge in the field.

The largest challenge we faced as a team during this project was to implement the high

frequency dc-ac converter. Since the frequency of the alternating current needed at the inductor was found to be 100 kHz using the skin depth equation for creating eddy currents in the aluminum can, we faced with the objective of designing a high frequency inverter. The H-bridge of the inverter and the 100 kHz gate driver was simulated to verify the operation of the design and after obtaining successful results we moved to implement the circuit. Even though the gate driver was operational as we expected from the simulation, the H-bridge wasn’t operational with our gate driver due to parasitic capacitance of the MOSFETs. This was a good learning opportunity for us. It was found that considering factors that may not be portrayed in simulations but could affect the real design should be paid special attention in the future. During this project, all of us learned well about challenges involved when designing high frequency converters.

Our device would have good operational capability with a working power source. Further

development of the inverter to be operational at 100 kHz or reducing the frequency to a lower value that can be still functional to create eddy currents in the graphite crucible will make our device well operational for the intended purpose of melting aluminum cans. Improvements can also be made for the heating element after testing with a proper power source. Number of turns in the inductor can be reduced if high enough temperatures can be reached with lower turns. This can reduce the cost of the device as less litz wire would be used and litz wire is the most expensive component of our device. Depending on test results, thickness of the insulation can also be reduced to make the heating element more compact and also to reduce the use of insulation material.

The finished product of our device would come in a well-insulated packaging. It would be a

simple plug-in and use product with the conventional power outlets. The power supply would include a rectifier and a inverter in a safe packaging with good cooling that can be plugged into an ac-outlet. The heating element would come as a detachable item from the power supply and would include simple plug-in and use with the power supply. This device could also be further developed to be used with an aluminum can collection machine similar to what we see nowadays used in grocery stores to crush cans and store until collected by recycling companies.

of 22

List of Appendices 1. Solving the Maxwell Equations

2. MATLAB Code - Computing Power

3. MATLAB Code - Solving the Thermal Model

4. Project Plan

5. Business Aspects

References Brennan, John. "Importance of Recycling Aluminum Cans." Home Guides | SF Gate,

http://homeguides.sfgate.com/importance-recycling-aluminum-cans-79304.html. Accessed 25 May 2019.

R. Phadungthin and J. Haema, "Application study on induction heating using half bridge LLC resonant inverter," 2017 12th IEEE Conference on Industrial Electronics and Applications (ICIEA), Siem Reap, 2017, pp. 1582-1585.

G.Liliana, “ Analysis and Design of a 500 kHz Series Resonant Inverter for Induction Heating Applications,” Ph. D. dissertation, Virginia Polytechnic Institute and State University , Virginia, pp.8-9,1995.

C. R. Sullivan, "Optimal choice for number of strands in a litz-wire transformer winding," in IEEE Transactions on Power Electronics, vol. 14, no. 2, pp. 283-291, March 1999.

J.Pyrhonen, T.Jokinen and V. Hrabovcova, Design of Rotating Electrical Machines, John Wiley & Sons,2008,pp-463-472.

1. Solving the Maxwell Equations

"⃗ $ % $& $' ()*+,-)./:12, 42 ()*+,-).//:122, 422 5-,:46, 1 = 0Maxwellequations:

∇ × ℎI⃗ = J⃗

∇ × +⃗ = −LMI⃗

L*

Linear,isotropicandhomogeneousconstitutiveequation:

J⃗ = 1+⃗

MI⃗ = 4ℎI⃗ Interfaceconditions:

YℎI⃗ Z − ℎI⃗ [\ ∙ *⃗ = _̂

(+⃗Z − +⃗[) ∙ *⃗ = 0

YMI⃗ Z − MI⃗ [\ ∙ bI⃗ = 0

(J⃗Z − J⃗[) ∙ bI⃗ = 0

∇ × Y∇ × ℎI⃗ \ = ∇ × J⃗ = 1∇ × +⃗ = −1LMI⃗

L*= −14

LℎI⃗

L*

Incylindricalcoordinateswehave:

L[ℎ[L,[

+1,Lℎ[L,

− 14Lℎ[L*

= 0

Usingthecomplextransformation:

ℎ[ = g(,) cos(h*) → ℎ[ = g (,)+jkl

Soℎ[ = ℛ+oℎ[pandqrsql= ^hg(,)+jkl

Thedifferentialequationbecomes:

v[gv,[

+1,vgv,

− ^h41g = 0

ItssolutionsarecomposedofthemodifiedBesselfunctionxyandzy

g(,) = 5x&({,) + |z&({,)

with{ = Z}j

~and� = Ä

[

ÅÇk

TheidentificationofAandBcomeswiththeboundarycondition.

ÖÜ(,) = −vgv,

= −5{xáZ({,) + |{záZ({,)

In, = $,g2($) = g_;

ℎI⃗ Z ∙ *⃗ = ℎI⃗ [ ∙ *⃗In, = $&,g2($&) = g22($&);

ℎI⃗ Z ∙ *⃗ = ℎI⃗ [ ∙ *⃗Ö2($&) = Ö22($&);

+⃗Z ∙ *⃗ = +⃗[ ∙ *⃗

In, = $', Ö22($') = 0;

+⃗Z ∙ *⃗ = +⃗[ ∙ *⃗Intheair+⃗[ = 0Itgivesthefollowingsetofequations,whichcanbesolvedwithsymboliccomputation.52x&({2$) + |2z&({2$) = g_52x&({2$&) + |2z&({2$&) = 522x&({22$&) + |22z&({22$&)

[−52xáZ({2$&) + |2záZ({2$&)]{212= [−522xáZ({22$&) + |22záZ({22$&)]

{22122

−522{22xáZ({22$') + |22{22záZ({22$') = 0

2. MATLAB Code - Computing Power

clear; close all; format long g; clc; % Material properties mu0 = 4*pi*1e-7; mur_I = 1; mu_I = mur_I*mu0; mur_II = 1; mu_II = mur_II*mu0; sigma_I = 170e3; sigma_II = 37.7e6; % Dimensions R=35.3e-3; Ro=23e-3; Ri=Ro-100e-6; L=113e-3; L=1/4*L kL=1.1; D_litz = 0.5106e-3; k_litz = 1; % in order to including small spacing between the wires N_layer =1; % Source fs = 100e3; Is = 2.1; Ns=round(N_layer*L/(k_litz*D_litz)); % Number of turns Hs = Ns*Is/(kL*L+D_litz); fprintf('Calculation of the power transmitted by eddy current in an aluminum tube\n\n'); fprintf('Outer Tube dimensions:\n\t Outer radius R = %.3g mm\n\t Inner radius Ro = %.3g mm\n\t Length L = %.3g mm\n\n', R*1e3,Ro*1e3,L*1e3); fprintf('Inner Tube dimensions:\n\t Outer radius Ro = %.3g mm\n\t Inner radius Ri = %.3g mm\n\t Length L = %.3g mm\n\n', Ro*1e3,Ri*1e3,L*1e3); fprintf('Magnetic field source:\n\t Amplitude Hs = %.3g kA/m at r=Ro\n\t Current Amplitude Is = %.3g A for %d turns with %d layers\n\t Frequency fs = %.0f kHz\n\n', Hs/1e3,Is,Ns,N_layer,fs/1e3); % discretization of the raidus Nr = 1500; rI = linspace(Ro,R,Nr); rII = linspace(Ri,Ro,Nr); % Skin depth delta_I = sqrt(2/(2*pi*fs*mu_I*sigma_I)); delta_II = sqrt(2/(2*pi*fs*mu_II*sigma_II)); fprintf('Eddy current characteristic\n\t Skin depth in outer tube: %.3g mm\n', delta_I*1e3); fprintf('\t Skin depth in inner tube: %.3g mm\n\n', delta_II*1e3);

a11 = besseli(0,(1+1j)/delta_I*R); a12 = besselk(0,(1+1j)/delta_I*R); a21 = besseli(0,(1+1j)/delta_I*Ro); a22 = besselk(0,(1+1j)/delta_I*Ro); a23 = -besseli(0,(1+1j)/delta_II*Ro); a24 = -besselk(0,(1+1j)/delta_II*Ro); a31 = -(1+1j)/delta_I/sigma_I*besseli(-1,(1+1j)/delta_I*Ro); a32 = (1+1j)/delta_I/sigma_I*besselk(-1,(1+1j)/delta_I*Ro); a33 = (1+1j)/delta_II/sigma_II*besseli(-1,(1+1j)/delta_II*Ro); a34 = -(1+1j)/delta_II/sigma_II*besselk(-1,(1+1j)/delta_II*Ro); a43 = -(1+1j)/delta_II/sigma_II*besseli(-1,(1+1j)/delta_II*Ri); a44 = (1+1j)/delta_II/sigma_II*besselk(-1,(1+1j)/delta_II*Ri); A_I = -(Hs*(a22*(a33*a44-a34*a43)-a23*a32*a44+a24*a32*a43))/(a12*(a21*(a33*a44-a34*a43)-a23*a31*a44+a24*a31*a43)+a11*(a22*(a34*a43-a33*a44)+a23*a32*a44-a24*a32*a43)); B_I = (Hs*(a21*(a33*a44-a34*a43)-a23*a31*a44+a24*a31*a43))/(a12*(a21*(a33*a44-a34*a43)-a23*a31*a44+a24*a31*a43)+a11*(a22*(a34*a43-a33*a44)+a23*a32*a44-a24*a32*a43)); A_II = (Hs*(a22*a31*a44-a21*a32*a44))/(a12*(a21*(a33*a44-a34*a43)-a23*a31*a44+a24*a31*a43)+a11*(a22*(a34*a43-a33*a44)+a23*a32*a44-a24*a32*a43)); B_II = -(Hs*(a22*a31*a43-a21*a32*a43))/(a12*(a21*(a33*a44-a34*a43)-a23*a31*a44+a24*a31*a43)+a11*(a22*(a34*a43-a33*a44)+a23*a32*a44-a24*a32*a43)); hz_I = A_I * besseli(0,(1+1j)/delta_I*rI) + B_I * besselk(0,(1+1j)/delta_I*rI); jphi_I = -(1+1j)/delta_I * A_I *besseli(-1,(1+1j)/delta_I*rI) + (1+1j)/delta_I * B_I *besselk(-1,(1+1j)/delta_I*rI); hz_II = A_II * besseli(0,(1+1j)/delta_II*rII) + B_II * besselk(0,(1+1j)/delta_II*rII); jphi_II = -(1+1j)/delta_II * A_II *besseli(-1,(1+1j)/delta_II*rII) + (1+1j)/delta_II * B_II *besselk(-1,(1+1j)/delta_II*rII); p_I = (jphi_I.*conj(jphi_I))/(2*sigma_I); p_II = (jphi_II.*conj(jphi_II))/(2*sigma_II); P_I = 2*pi*L*trapz(rI,rI.*p_I); P_II = 2*pi*L*trapz(rII,rII.*p_II); % Calculation of the inductance Flux = 2*pi*(Ri^2/2*mu0*real(hz_II(1))+ mu_I*trapz(rI,rI.*real(hz_I))+ mu_II*trapz(rII,rII.*real(hz_II))); Ls = Ns * Flux/(Is); Vs = 2*pi*fs*Ls*Is; Papp=Vs*Is; fprintf('\t Inductor characteristics:\n'); fprintf('\t Inductance : L = %.3g \x03BC H \n',real(Ls)*1e6); fprintf('\t Voltage required (resistance neglected): V = %.3f V \n',Vs); fprintf('\t Transmitted power in outer tube: P_I = %.3f W \n',P_I);

fprintf('\t Transmitted power in inner tube: P_II = %.3f W \n',P_II); fprintf('\t Total Transmitted power: P = %.3f W \n',P_I+P_II); fprintf('\t Apparent power : S = %.3f kVA \n\n',Papp/1e3); % Display the distrubution of the electro-magnetic quantities r=[rII rI]; hz=[hz_II hz_I]; jphi=[jphi_II jphi_I]; p=[p_II p_I]; P=P_I+P_II; figh=figure(1); subplot(3,1,1); plot(rII*1e3,real(hz_II)/1e3,'b',rII*1e3,imag(hz_II)/1e3,'r',rI*1e3,real(hz_I)/1e3,'c',rI*1e3,imag(hz_I)/1e3,'m'); xlabel('r [mm]'); ylabel('field [kA/m]'); legend('Real in inner tube','Imaginary in inner tube','Real in outer tube','Imaginary in outer tube','Location','Best'); subplot(3,1,2); plot(rII*1e3,real(jphi_II)*1e-6,'b',rII*1e3,imag(jphi_II)*1e-6,'r',rI*1e3,real(jphi_I)*1e-6,'c',rI*1e3,imag(jphi_I)*1e-6,'m'); xlabel('r [mm]'); ylabel('current density [A/mm^2]'); legend('Real in inner tube','Imaginary in inner tube','Real in outer tube','Imaginary in outer tube','Location','Best'); subplot(3,1,3); plot(rII*1e3,real(p_II)/1e6,'b',rII*1e3,imag(p_II)/1e6,'r',rI*1e3,real(p_I)/1e6,'c',rI*1e3,imag(p_I)/1e6,'m'); xlabel('r [mm]'); ylabel('power density [MW/m^3]'); legend('Real in inner tube','Imaginary in inner tube','Real in outer tube','Imaginary in outer tube','Location','Best'); hcv = 10; S=2*pi*R*L+2*pi*R^2; q=P/S; dT= q/hcv; fprintf('Thermal characteristic\n\t Temperature rise : \x0394 T = %.0f \x00B0 C \n',dT); fprintf('\t Fusing temperature of the aluminium : T = 660 \x00B0 C\n'); fprintf('\t Fusing temperature of the steel : T = 1 450 \x00B0 C\n'); fprintf('\t Fusing temperature of the graphite for crucible : T = 3 850 \x00B0 C\n\n'); L=113e-3; Thermal_model_IH

3. MATLAB Code - Solving the Thermal

Model

%% Thermal Resistances l_y=19*1.1e-3; %Number of insulation layers A_L=134e-3; %Aluminum Can length L_th=D_litz/2; %Litz wire radius alpha_C=30; %Convection Coefficient lam_cop=380; %Conductivity of Litz wire lam_al=220; %conductivity of Aluminum lam_in=0.045; %conductivity of Insulation lam_gh=168; %conductivity of graphite Ral_out=26.65e-3; % Outer radius of Aluminum Ral_in=26.59e-3; % inner radius of Aluminum Ral=(log(Ral_out/Ral_in))/(2*pi*lam_al*A_L); %Thermal resistance of Aluminum Rin=(log((l_y+R)/R))/(2*pi*L*lam_in); %Thermal resistance of Insulation Rg=(log(R/Ro))/(2*pi*L*lam_gh); %Thermal resistance of Graphite RL=(log((R+l_y+2*L_th)/(R+l_y)))/(2*pi*L*lam_cop); %Thermal resistance of Litz wire RC1=(1/(alpha_C*2*pi*(R+l_y+2*L_th)*L)); % Convection Resistance Litz wire side n=70; %Number of Strands l_wire = 2*pi*(R+l_y+D_litz/2)*Ns+50e-3; %length of total turns and additional length L_rho=1.72e-8; d_43=0.05641e-3; S_litz = n*pi*(d_43/2)^2; R_litz = 2.8 %% Graphite Resistance Rg_rho=7.837e-6; Rg_r=(Rg_rho*L)/(pi*((R)^2-(Ro)^2)); %%Aluminum Resistance Ral_rho=2.65e-8; Ral_R=(Ral_rho*L)/(pi*((Ral_out)^2-(Ral_in)^2)); %%Losses P_L=Is^2*R_litz; %Litz wire loss V_need = sqrt((R_litz*Is)^2+Vs^2) P_G=P_I; %Graphite loss P_A=P_II; %Aluminum loss %% Thermal Resistances Aluminum Side lamb_air=66.32e-3; R_air=((A_L/3))/(lamb_air*pi*(Ral_out)^2); % Air resistance e_al=0.24e-3; R_altop=(e_al)/(lam_al*pi*(Ral_out)^2); % Aluminum Top side resistance R_cv2=(1/(alpha_C*pi*(Ral_out)^2)); %Convection Resistance Aluminum Side r_2=26.53e-3; %excluding Aluminum thickness r_1=0.1e-3; R_almid=(log(r_2/r_1)/(2*pi*A_L*lamb_air)); %%Equivalent Resistances R1=(RC1+(RL/2)); R2=((RL/2)+(Rg/2)+Rin); R3=((Rg/2)+(Ral/2)); R4=((Ral/2)+R_air+R_altop+R_cv2+R_almid);

%% Equations Tamb=20; %ambient temperature F = ((R2*R3)*(R3+R4))/((R3*(R3+R4))+(R2*(R3+R4))-(R2*R4)); Q = F*(((R4/(R3+R4))*((((Tamb/R4)+P_A))+P_G))); E = (R1*(R2)^2)/((R2^2)-(F*R1)+(R1*R2)); T_A = E*((Tamb/R1)+P_L+(Q/R2)); T_B = F*(((T_A/R2)+(R4/(R3+R4)))*(((Tamb/R4)+P_A)+P_G)); T_C = R3*R4/(R3+R4)*(Tamb/R4+T_B/R3+P_A); disp(T_A) disp(T_B) disp(T_C) TA = (R1*Tamb + R2*Tamb + R3*Tamb + R4*Tamb + P_A*R1*R4 + P_G*R1*R3 + P_G*R1*R4 + P_L*R1*R2 + P_L*R1*R3 + P_L*R1*R4)/(R1 + R2 + R3 + R4) TB = (R1*Tamb + R2*Tamb + R3*Tamb + R4*Tamb + P_A*R1*R4 + P_A*R2*R4 + P_G*R1*R3 + P_G*R1*R4 + P_G*R2*R3 + P_G*R2*R4 + P_L*R1*R3 + P_L*R1*R4)/(R1 + R2 + R3 + R4) TC = (R1*Tamb + R2*Tamb + R3*Tamb + R4*Tamb + P_A*R1*R4 + P_A*R2*R4 + P_A*R3*R4 + P_G*R1*R4 + P_G*R2*R4 + P_L*R1*R4)/(R1 + R2 + R3 + R4)

Aalto University

ELEC-E8004 Project work course

Year 2019

Project plan

Project #26

Induction Heater for Melting Aluminum

Date: 1.2.2019

Yuvin Kokuhennadige

Md Masum Billah Joni-Markus Hietanen

Jaakko Lind

Page 1 of 21

Information page

Students Yuvin Kokuhennadige Md Masum Billah Joni-Markus Hietanen Jaakko Lind Project manager Yuvin Kokuhennadige Official Instructor Dr. Floran Martin Starting date 10.1.2019 Approval The Instructor has accepted the final version of this document Date: 1.2.2019

Page 2 of 21

1) Background

This project is based on electromagnetic induction, as time-dependent magnetic field induces electric current to a conductive material. Induced currents are referred to as eddy currents, and current generates heat as it flows through a conductive material, such as metal. This is the general working principle behind all induction heating devices, most common of which may be the induction stove. In industrial applications, induction heaters can be used to generate heat in metallic objects locally and efficiently, even to the point where metals are melted completely.

The project work consists of designing and building an industrial induction heater, capable of melting aluminum cans. Changing magnetic field is generated with an inductor, and the workpiece (in this case the aluminum can) is placed inside it to produce eddy currents and therefore heat within the workpiece. An inductor requires alternating current input, which can be supplied using high power transistors, such as MOSFETs or IGBTs. These transistors can be controlled by a function generator or dedicated gate-drivers to achieve desired output frequency, voltage and current required for the magnetic field and therefore eddy currents. Also, some additional cooling has to be introduced to the inductor coil to prevent it from overheating, as only the workpiece should be heated.

Motivations for this device include more efficient recycling (and shipping) of aluminium cans and potentially even larger pieces of aluminium, such as induction machine rotors. If cans would be melted after collecting, they would not take up so much space and more material could be shipped at once, with just a relatively slight change to the recycling procedure. Also, this device would enable on-site melting of material, making the whole recycling process more efficient. Recycling of aluminium is much less expensive and energy-intensive, and more sustainable than creating new aluminium, as it requires approximately 95% less energy compared to generating new aluminium from minerals. 2) Expected Output

As covered in section 1, the goal of this project is to melt aluminium cans using an induction heater. The goal and expected output of the device is to be able to create desired frequency, current and voltage to the induction coil which induces needed eddy currents on the workpiece, in order to melt it. The system inputs are aluminium cans and power to the power electronics so that the output is melted aluminium which can be processed again. The system must be robust enough to withstand the high temperature and high currents needed for the melting process. One of the goals for this project is good performance for the system. The melting process should not take extended period of time. The user would like the aluminium to melt as fast as possible. The time is the key issue of the system. The system also needs to be safe for the user and not cause any hazards to the surroundings. Proper insulation and cooling system will be there to prevent any unwanted events.

The expected user of the system is one person who should be able to use the heater very easily. Only one switch is needed for this system to work and perform the melting process. The system could later be used as an example to create larger scale recycling systems for aluminium cans as our project is not designed to process large number of cans in short period of time.

When the project is ready and we confirm that it works as intended, we can decide how to present it. There are two options for this demonstration: either we can show the melting process in action or shoot a video of it in safer environment and then present the outcome on screen for the viewers. The way of demonstration can be specified after we know exactly how the finished system works. Showing a video is safer option however it’s not as exciting as real physical demonstration.

Page 3 of 21

3) Phases of the Project

This project is split into phases in order to work with a higher-level goal in mind. M1 Planning (Deadline: 4.2.2019)

In the planning phase, we layout a plan to complete the project successfully and in a timely manner. In this phase, we can clearly identify the objective of the project, required project outcomes, scheduling, budgeting, division of labour and so on. Some literature review will also be done in order to familiarize ourselves with the project. This document (Project Plan) is the documented version of the plan for this project.

M2 Conceptualization (Deadline: 18.2.2019)

The phase where intense literature review is done to understand each part of the project. The concepts necessary to implement the project will be identified in this stage.

M3 Prototyping (Deadline: 18.3.2019)

Identified concepts will be tested in this phase by implementing a preliminary model. This prototype will be the base for this project. After preliminary testing, improvements would be done for this prototype directly if possible.

M4 Subsystem completion (Deadline: 15.4.2019)

In this phase, the prototyped model is taken into consideration as subsystems. Each subsystem will be tested to evaluate its performance. Each subsystem will then be improved to be more efficient and reliable if possible.

M5 System completion and integration (Deadline: 6.5.2019)

Separately tested and improved subsystems will be integrated in this phase to complete the system. Integration testing will be conducted to make sure the subsystems can operate as anticipated.

M6 Final delivery (Deadline: 20.5.2019)

In order to prepare for delivery, the project will be tested for the intended application. The final product will be demonstrated to the instructor, advisors and to others who are interested.

M7 Presentation (Deadline: 21.5.2019)

A poster presentation will be prepared to present the project at the Final Gala. Developed project could also be on display. Attendees will be able to get a detailed background of our project and we will be available to answer any questions they may have. The poster designs should be ready by May 13th for submission.

M8 Project Report (Deadline: 31.5.2019)

The project report will present details of how the project was developed, the problems faced during development and any significant improvements that could be made to the product to be more useful. The report will also include measurements during testing, details of set up used and details of materials and parts used.

Page 4 of 21

4) Work breakdown structure (WBS)

Induction Heating Device ( 810 h, 100%)

1. Concept (139 h, 17%) 1.1 Project plan (48 h) 1.2 Literature review (55 h) 1.3 Identify needs (36 h)

2. Development (142 h, 18%) 2.1 Converter design (48 h) 2.2 Transformer design (18 h) 2.3 Induction coil design (24 h) 2.4 Thermal model analysis (24 h) 2.5 Materials list (20 h) 2.6 Pre cost analysis (8 h)

3. Implementation (206 h, 25%) 3.1 Materials gathering (14 h) 3.2 Converter ( 96 h) 3.3 Transformer (24 h) 3.4 Induction coil (16 h) 3.5 Cooling System (36 h) 3.6 Connections setup (20 h)

4. Finalization (66 h, 8%) 4.1 Performance analysis (4 h) 4.2 Troubleshooting (48 h) 4.3 Risk analysis (6 h) 4.4 Final inspection (4 h) 4.5 Post cost analysis (4 h)

5. Documentation ( 192 h, 24%) 5.1 Business Aspects Presentation (48 h) 5.2 Business Aspects Documents (48 h) 5.3 Final Report (96 h)

6. Communication (65 h, 8%) 6.1 Meeting Time (25 h) 6.2 Gala Day (40 h)

Page 5 of 21

5) Work packages and Tasks of the project and Schedule

5.1) Work packages

5.2) Tasks

WP-1 Project Management and Coordination 1.1 Scheduling (25 h) 1.2 Budgeting (12 h) 1.3 Defining division of labour ( 14 h) 1.4 Project planning (48 h) 1.5 Risk evaluation (6 h) 1.6 Gala Day (40 h)

WP-2 Power Electronics Conceptualisation

2.1 Literature review (25 h) 2.2 Identify Needs (15 h) 2.3 Select Components (10 h) 2.4 Simulate inverter (28 h) 2.5 Simulate rectifier (20 h) 2.6 Simulate transformer (28 h) 2.7 Making material list and order ( 10 h)

Page 6 of 21

WP-3 Coil Design Conceptualisation 3.1 Literature review (15 h) 3.2 Identify needs (5 h) 3.3 Calculate Frequency ( 3 h) 3.4 Copper tube thickness (2 h) 3.5 Copper tube diameter (2 h) 3.6 Coil diameter (2 h) 3.7 Finding Number of coil turns (4 h) 3.8 FEM(M) simulation (24 h) 3.9 Making materials list and order (5 h)

WP-4 Cooling System Conceptualisation

4.1 Literature review (15 h) 4.2 Identify needs (6 h) 4.3 Selecting water pump or Fan (3 h) 4.4 Making materials list and order (5 h)

WP-5 Power Electronics Implementation

5.1 Design PCB layout (30 h) 5.2 Soldering parts (60 h) 5.3 Providing insulation (5 h) 5.4 Transformer coil forming (24 h)

WP-6 Coil Design Implementation

6.1 Bending copper tube to make an inductor (8 h) 6.2 Fabricating the mount with power supply (8 h)

WP-7 Cooling System Implementation

7.1 Selecting space for pump installation ( 6 h) 7.2 Installing water pump (30 h)

WP-8 Testing Power Electronics

8.1 Checking required voltage ( 1 h) 8.2 Checking required current ( 1 h) 8.3 Checking required frequency (1 h) 8.4 Calculate efficiency (3 h)

WP-9 Testing Coil

9.1 Checking voltage through current (1 h) 9.2 Checking current through coil (1 h) 9.3 Calculate resistive losses (3 h)

WP-10 Testing Cooling System

10.1 Ensure sufficient water flow (2 h) 10.2 Checking time accuracy of water flow (1 h)

Page 7 of 21

WP-11 System Integration 11.1 Connecting the whole setup (20 h) 11.2 Overall performance evaluation ( 4 h) 11.3 Contingency planning if necessary (33 h) 11.4 Final demonstration (4 h)

WP-12 Documentation 12.1 Business aspect presentation (48 h) 12.2 Business aspects documents (48 h) 12.3 Final Report (96 h)

5.3) Detailed schedule

Page 8 of 21

6) Work resources (Personal availability during the project)

Personal availability of each group member is mentioned here in order to evaluate how much work each person can put towards the project during different times depending on their changing schedules. By balancing out the work between one member who has a busy week with a member who is free, the project can progress steadily. Table 1. Number of hours available for the project (excluding lectures and seminars) per week.

Yuvin Kokuhennadige Jaakko Lind Joni-Markus

Hietanen Md Masum Billah

Week 2 2 5 2 2 Week 3 10 15 15 15 Week 4 15 15 15 10 Week 5 15 8 10 15 Week 6 8 15 12 8 Week 7 15 10 12 6 Week 8 15 10 12 15 Week 9 4 12 14 6 Week 10 8 12 8 7 Week 11 8 12 6 9 Week 12 8 12 12 15 Week 13 8 12 12 8 Week 14 4 5 4 12 Week 15 4 5 4 5 Week 16 12 12 14 10 Week 17 12 10 12 12 Week 18 12 10 10 6 Week 19 12 5 8 10 Week 20 15 5 7 15 Week 21 4 5 6 7 Week 22 10 5 6 15

Total 201 200 201 208

Page 9 of 21

7) Cost plan and materials

Maximum budget defined by the instructor in the preliminary meeting was 500 Euros. Budget is controlled by the project manager, and all purchases have to be approved by him before ordering is completed. As the responsibility of budget management is focused to a single person, chances of obscurity are greatly decreased.

Table 2. Cost Estimation

Item Type Quantity Price per piece (€)

Estimated cost (€)

Rectifier set Device 1 100 100

MOSFETs or IGBTs Component 12 2.05 24.60

Fusing Component 4 6 24

Free-wheeling diodes Component 12 5 60

Driver IC Component 12 3 36

Zener diodes Component 12 0.5 6

Optocouplers Component 12 0.5 6

Inductor Component 2 10 20

Inductor mounting Service 1 50 50

Fan Component 2 7 14

Pump Device 1 10 10

Tubing Component 2 5 10

Additional General - - 100

Total cost 360.6

Page 10 of 21

8) Other resources

Besides all the components we need some other resources for this project as well. The most notable resource is the working place we are supposed to use for the construction of the system. The working place is going to be the laboratory of the Department of Electrical Engineering. We will need keys for the facility, and this can be discussed with our instructor. In the laboratory we will be using one table for our project and keep our place organized so that it doesn’t affect work of other people.

There is most likely going to be a need for some tool to shape the copper induction coil. For this we are going to need some tools that the university has. We will need at least some instruction and supervision for using such a tool. We will communicate about this with our instructor as he is the one knowing who we should be working with in this case. The needed welding tools are more easily accessible and can use them with less or completely without supervision.

Other than these resources we are of course going to use the electricity that is provided in the laboratory and use all the required safety measures that are introduced to us. In our project we won’t be needing computers from the university as we can use our own laptops. 9) Project management and responsibilities

Important project roles and responsibilities of each role is defined below.

Role Responsibilities

Project Manager (Yuvin Kokuhennadige)

● Planning work ● Providing access to resources ● Reporting progress ● Budget management ● Making sure overall work progresses and deadlines are met ● Leading overall technical aspects of the project and delegating ● Preparing meeting agendas and reserving meeting rooms ● Placing orders for materials/parts to complete overall project

Instructor (Dr. Floran Martin)

● Provide rough background about the project ● Observe progress of the project ● Provide expert technical advice if needed ● Ensure safety during experimental testing ● Review and approve documentation before submission

Coil Design Lead (Md Masum Billah)

● Lead developing Electromechanics subsystem ● Responsible for system integration ● Making sure design deadlines are met per schedule ● Placing orders for materials/parts specific to coil design

Power Electronics Lead (Joni-Markus Hietanen)

● Lead developing Power Electronics subsystem ● Making sure design deadlines are met per schedule ● Placing orders for materials/parts specific to power electronics

Cooling System Lead (Jaakko Lind)

● Lead developing the cooling system ● Making sure design deadlines are met per schedule ● Placing orders for materials/parts specific to the cooling system

Page 11 of 21

10) Project Meetings

Project meetings between group members and the instructor will take place once a week unless otherwise suggested that more meetings are needed depending on weekly needs of the project. In the early stages of the project, meetings will be for understanding the topic in detail and to create the project plan. After creating the project plan, implementation will begin and the project meetings will be held to track progress of the project and to discuss any issues that the project faces.

Preparing meeting agendas is the responsibility of the project manager. The agenda will be shared with the attendees by email at least 24-hours before the meeting. Agenda will also be available on the Google Drive folder, ELEC-E8004 Project Work -> Agendas. The template for project meeting agendas is shown below:

Meeting Agenda

Date: dd.mm.yyyy

● Select memokeeper.

● Updates relevant to overall project since last meeting.

● Updates specific to the coil design.

● Updates specific to power electronics.

● Compare the progress with planned schedule.

< include.planned schedule >

● If falling behind the planned schedule, plans and action on how to catch up.

● What should be done before next meeting by each person.

● Decide next meeting date, time and place.

* Next meeting will commence at the exact time decided and mentioned in the meeting minutes.

(Usually at the beginning of the hour, unless otherwise specified.)

Page 12 of 21

Meeting memos will be prepared in order to refer back to decisions made at meetings, remind assigned tasks for each person and any other important discussion that should be referred to during the tasks for the week. Meeting memos could be taken by any member of the group other than the project manager, as the project manager should lead the discussion of agenda items. The template for project meeting memos is shown below:

Meeting Memo Date: dd.mm.yyyy

Memokeeper:

For each phase of the meeting take notes of:

● Decisions made at the meeting.

● Tasks assigned to a specific person.

● Important discussions.

* Please follow this format and take notes as bullet points. When assigning tasks, include the name

of the person in bold . After the meeting, please upload the final memo to the Google Drive folder,

ELEC-E8004 Project Work -> Meeting Memos, within 24-hours.

Overall project updates

● ...

Coil design updates

● ...

Power electronics updates

● ...

Inconsistencies with planned schedule

● ...

Tasks to be completed before next meeting

● Yuvin:

● Masum:

● Joni-Markus:

● Jaakko:

Next meeting

Date: dd.mm.yyyy

Time:

Place:

* Next meeting will commence at the exact time mentioned.

Page 13 of 21

11) Communication plan

Peer Meeting Schedule

Date Agenda Time Types

17.01.2019 Preliminary Report 13.00-14.00 Face to Face

22.01.2019 Project Plan 16.00-17.00 Online

29.01.2019 Project Plan 12.00-14.00 Face to Face

02.02.2019 Project Plan 15.00-16.00 Online

04.02.2019 Design kickoff 11.00-13.00 Face to Face

11.02.2019 Preliminary Design 12.00-11.30 Face to Face

15.02.2019 Final Design 17.00-18.00 Online

25.02.2019 Implementation Kickoff 12.00-14.00 Face to Face

31.02.2019 Business Aspects Presentation 12.30-14.00 Face to Face

07.03.2019 Business Aspects Presentation 15.00-16.00 Online

08.03.2019 Business Aspects Documents 16.30-18.00 Online

13.03.2019 Business Aspects Documents 11.00-12.00 Face to Face

29.03.2019 Implementation 10.00-11.00 Online

07.04.2019 Implementation 12.30-13.30 Face to Face

12.04.2019 Implementation 11.00-130.00 Face to Face

23.04.2019 Poster Design 13.00-14.00 Face to Face

30.04.2019 Performance Evaluation 12.00-13.00 Face to Face

05.05.2019 Final Report Kickoff 14.00-16.00 Face to Face

09.05.2019 Report writing 18.00-19.00 Online

12.05.2019 Report writing 16.00-17.00 Online

17.05.2019 Gala Day 15.00-16.00 Face to Face

28.05.2019 Final Report 13.00-15.00 Face to Face

30.05.2019 Final Report 18.00-20.00 Online

Page 14 of 21

Instructor Meeting Schedule

Date Agenda Time

18.01.2019 Preliminary Report 11.30-12.30

01.02.2019 Project Plan 11.00-12.00

13.02.2019 Design Aspects 10.30-11.30

21.02.2019 Final Design Outcomes 11.30-12.30

26.02.2019 Implementation Aspects 12.00-13.00

06.03.2019 Business Aspects 11.00-12.00

12.03.2019 Business Aspects Documents 10.00-11.00

27.03.2019 Implementation Issues 12.00-13.00

30.04.2019 Performance Evaluation 12.30-13.30

15.05.2019 Final Report and Gala Day 11.00-12.00

17.05.2019 Gala Day 10.30-11.00

29.05.2019 Final Report and Giving Thanks 11.00-12.00

12) Risks

General project risk analysis has in this case been defined to consist of six steps. These six steps are used to clarify the characteristics of individual risks, their probability and potential damage they possess to overall project work. As we’re dealing with a hardware-based project, safety factors are being considered within these risks, to ensure a safe working environment during the whole project. Steps are presented below: Project Risk Analysis:

1. Risk event: What might happen to affect your project or individuals? 2. Risk timeframe: At what phase of the project is it likely to happen? 3. Probability: What’s are the chances of it happening? 4. Severity of the impact: What’s the expected outcome and how does it affect the project? 5. Recognition of factors: What events might forewarn or trigger the risk event and how to

recognize them in advance? 6. Handling: Concrete measures to reduce risk.

Page 15 of 21

Table 3. Risk Analysis

Risk Type Severity Recognition

Delay 1 Careless planning and impossible deadlines

Aluminium oxide 1 Impurities on the recycled end product

Component shipping 2 Ordering components from suspicious sources

Component expenses 3 Careless planning and overpriced components

Paint fumes 3 Paint on the cans has to be noted and removed

Design flaws 4 Careless planning and insufficient simulations

Fire hazard 5 Overheating of inductor or ignition of material

Severity scale: 1 Risk is there, minor damage may occur in terms of time-management. 2 Low-level damage may occur. Fixing the damage may take time and effort. 3 Mid-level damage may occur in terms of budget, time management or minor injuries. 4 Genuine risk exists, injuries are possible. 5 Very severe safety risks. Catastrophic damage or severe bodily injury may occur. Delay:

1. Delay is a risk that covers a lots of sectors within the project work. Overall delay may lead to time management issues to some deadlines during the project and may in the worst case lead to unsuccessful project altogether.

2. Delay may occur in any phase of the project. 3. Occurrence of this risk is highly probable. 4. Severity differs on magnitude and point of time in the project 5. Careless planning and impossible deadlines are factors to be considered in advance 6. Elaborate plans and early enough orders of parts may help, but delay can’t be completely

averted.

Aluminium Oxide: 1. Aluminium oxide is generated within the melting process of aluminium. It is a chemical

compound, that consists of aluminium and oxygen. It is not toxic, but creates some impurity to the aluminium collected after melting.

2. Risk is topical after device is successfully built and pure aluminium is wished to be recycled.

3. Occurrence of this risk is somewhat potential. 4. Severity of this risk is quite low, as it has an effect on the recycled end product rather than

being relevant on the production process of the device. 5. Impurity can be recognized from the recycled end product. 6. Impurities could be separated after melting process.

Page 16 of 21

Component Shipping: 1. Component shipping may generate significant delay to the process. 2. Risk is topical during ordering of parts. 3. Occurrence of this risk is quite probable. 4. Severity of this risk is quite low, as it only has an effect on the time management section of

the process. 5. Ordering components from suspicious sources. 6. Risks can be reduced by ordering most components simultaneously from well-established

websites and other verified sources, with previously defined shipping times.

Component Expenses: 1. Component expenses may exceed the project budget, if not carefully selected and handled

during the prototyping phase. 2. Risk is topical during the whole project, but especially at the prototyping phase. 3. Occurrence of this risk is possible. 4. Severity of this risk is mid-level, as exceeded budget is one measure of successful project. 5. Careless planning and overpriced components or materials are the most relevant factors. 6. Careful simulations before implementation of components and price comparison before

purchasing components.

Paint fumes: 1. Harmful and irritating paint fumes may possess a health risk when inhaled. During this

project, the paint considered is located on the surface of the aluminium cans. 2. Risk is topical when heating the cans. 3. Occurrence of this inhalation risk is somewhat possible. 4. Severity is mid-level, as it may lead to some health issues during the project work. 5. Paint on the cans has to be noted beforehand. 6. Risk can be removed by removing the paint from the workpieces before applying heat to the

aluminium. Design Flaws:

1. Design flaws is one of the biggest and widespread risks on the project, as it may lead to serious hardware malfunctions.

2. Risk is topical around the project design phase and on the prototyping phase. 3. Occurrence of this risk is possible. 4. Severity depends on the type of design flaw and potential malfunction, but it may lead to

financial issues, time-management failures and even injuries. 5. Recognition of design flaws can be done by careful planning and simulation of different

sections of the project. 6. Sufficient simulation before implementing the physical project.

Page 17 of 21

Fire Hazard: 1. Fire hazard possesses most dangerous risk of the list, as it may lead to serious injury or

complete physical destruction of the project. Even surroundings may be in serious danger. 2. Risk is topical on prototyping phase as well as after the project has been completed. 3. Occurence of this risk is possible. 4. Severity of this risk is obvious, as a fire may lead to serious damage to the project, people

and test environment. 5. Unwanted ignition of any material or overheating of the inductor. 6. Preparation with fire extinguishing equipment as well as preliminary heat analysis and

efficient cooling system. Heating event must be constantly examined and evaluated.

13) Quality plan

The quality of every phase of the project will be monitored with the best of groups abilities. Group members will complete their tasks trying to achieve the best possible quality as this helps the project greatly. The whole group is responsible for quality and everyone may point out flaws or weaknesses in any phase of the project as this makes it faster to improve the needed aspects of the current project phase.

Before each phase of the project the group should have meetings on how to proceed and make the next goals as clear as possible. When everyone in the group knows exactly what they are aiming for, the quality of the project will improve. After each task the project manager will be doing some final checking and then approve the work or point out some recommendations how to better something. For example, when thinking about the planning phase of the project, the project manager will read the whole document and send it to approval for the instructor if the aimed quality is achieved.

The project manager is not fully responsible for the quality of the project, but he will be the one approving the work of the group. This approval can be done by organizing a group meeting and then approving the quality collaboratively. The quality approval is done differently for different phases of the project, but the idea is the same. For example, the project plan is checked for all the needed and accurate content that are ensure good quality. And if we think about the prototyping, the quality can be seen by doing all the necessary testing for the system. If these tests are passed, the wanted quality is achieved and we may proceed to next phase.

The instructor will have role in the quality of the project. He is going to be the person who can say the final word on each project phases and give the project group feedback on the quality. The instructor will be the final person who approves the project plan and other phases of the project. Instructor may give the project group feedback on the quality and give suggestions to improve it if needed.

If anyone in the group notices something that is affecting the quality in a negative way, the person may contact other people in group chat and point out the things that were found. In case the issue is small and can be corrected easily, the right group member will deal with the issue right away. However, if the flaw in the quality is bigger, a group meeting should be invited, and the topic discussed so that the project work can be continued with the improved quality.

Page 18 of 21

14) Changing this plan

Anyone in the project group is able to make initiative to ask possible changes to this project plan. No matter how big of a change is going to be, the person should inform the group that something worth changing is found in the document. This is easiest to do by contacting other members in group chat. Changing something without consent of other members should not be done unless the change is something really minor, like a spelling error.

After the initiative is taken, the group should agree on how to change the document. This is easiest to do in a group meeting as everyone can give their opinions easily and discussion can be made. If the change is going to be easy and straightforward, the group can agree the changes in group chat and let the person do the needed changes. If something more significant part is going to be changed, the group should plan it together and come to an agreement.

Changing the schedule is going to be done in the same way as any other larger scale change. The whole project group should agree fully on changing the schedule as it affects everyone’s work. If the proposed schedule change is fine for all the members, the change will be done to the document. If someone is absent, the others will tell the person by message what changes are to be made. If for example the schedule doesn’t work for the absent person, the change will be discussed further.

If changes are made to the project plan, the changes should be also documented in the plan. When the document is kept up to date it is easy to follow it and it prevents also misunderstandings. The best way to keep track on the possible changes is to add one more section to the end of the project plan. This last section could be titled for example Revision history. There we could make a table that shows the date of the change, the person who changed it and the actual information that changed. For example, the table could look like this:

Date

Person who did the change

Change

xx.xx.xxx Xxxxxxx Something was changed in section X

Page 19 of 21

15) Measures for successful project

The definition for successful project is to build a functioning prototype capable of melting aluminium cans in a short period of time, while reaching budget goals and technical milestones within the defined deadlines.

Evaluation of final outcome includes functionality of the device and its parts. If all parts are functional, induction heater is evaluated as whole, by the delay it takes to fully melt an aluminium can. Demonstration of functional project can be done either physically on class seminar, which possesses some obvious risks, or on laboratory conditions evaluated by the instructor. Functionality of the finished product could be verified on safe laboratory conditions and a film demonstrating the functionality could be viewed on seminar conditions. This gives the viewers an opportunity to evaluate the functions without sacrificing classroom safety.

Evaluation of process is based on reaching the previously defined milestones, that describe deadlines and targets for each section. Reaching previously defined milestones must be documented and evaluated along the whole project process in order for the evaluation to be reliable and relevant in the end.

Individual goals can also be defined for each student independently, as tasks within the project work lead to different kind of learning experiences. Also it is notable, that learning goals differ according to preliminary knowledge possessed by each individual. If all sections of the process and areas of responsibilities are clearly divided beforehand, individual evaluation is easier. Received feedback and self-evaluation along the project work as well as after it support the learning goals, that students have defined.

Overall, the evaluation for a successful project consists of the previously mentioned factors, which include a functioning prototype, reached budget limitations, reached technical milestones and deadlines, successful demonstration of prototype functionality and its waypoints as well as independently reached learning goals for each student.

Page 20 of 21

Appendix

1) Work Breakdown Structure (WBS)

Page 21 of 21

Aalto University ELEC-E8004 Project work course

Year 2019

Business aspects

Project #26

Induction Heater for Melting Aluminum

Date: 15.3.2019

Kokuhennadige Yuvin Billah Md Masum

Hietanen Joni-Markus Lind Jaakko

Page 1 of 11

Information page

Students A Kokuhennadige Yuvin B Billah Md Masum C Hietanen Joni-Markus D Lind Jaakko Project manager Kokuhennadige Yuvin Official instructor Dr. Martin Floran Starting date 19.2.2019 Approval The instructor has accepted the final version of this document Date: 15.3.2019

Page 2 of 11

Summary

With an enormous number of population growth and high living standard, the recycling products are increasing day by day. Nowadays, recycling is an important issue to keep the environment clean, save landfills and reduce the need for raw materials. Aside from these benefits, the recycling industry can be a good source of business. Aluminum is one of the most recycled products in the metal recycling family. Almost 40% of the recycling metals are aluminum and each year the world is spending billion euros for recycling the Aluminium.

Aluminum beverage Can is the most recycled consumer products and takes lots of space. Collecting Aluminum Can from consumer to the recycle industry cause a large amount of transportation cost and huge space at the collection point. These issues can be solved by setting a melting device in the Can collection point but the traditional melting devices are large in size and takes lots of time to melt the Aluminium Can which is difficult to fit in the collection point. A fast melting and equal size of Can collection machine can resolve this problem. The recycler can save transportation cost by directly transport the molten Aluminum from collection point to the Aluminium products manufacturers rather than taking it to the recycling center.

Induction heating system can be a game changer in Aluminium Can recycling industry because of its fast, safe and highly efficient heating system. Therefore, our primary business goal is to manufacture a fast, small size, efficient and eco-friendly induction melting device that can significantly reduce the volume of the Aluminium Can by melting this in collection point and minimize the transportation cost for the recyclers. In addition, this device can also substitute the usage of Can collection machines.

The global market size of Aluminium recycling machinery is around 1.2 billion euros. Our initial target is 35 companies and their 5000 collection points which will make the revenues of 50 million euros in five years. The market is quite open, homogeneous and exists almost perfect competition. Therefore, our product can able to substitute other products easily as there are no significant entry barriers into the market. After achieving our primary target we will expand our market to other Aluminum recycling companies. As the recycling machinery has a longer lifetime and the market saturation can occur in the future. Therefore, market expansion is necessary to lessen this crisis. Our product has the ability to melt any materials who has equal or below the melting point of Aluminum. To overcome from this market saturation we will launch our product to the other recycling materials industry in the future.

1) Business idea

Our end product is an induction heater which includes the heating element and the power supply. Our induction heater will be a compact heater that can reach high temperatures very fast to melt aluminum cans. Since the main application of our design is to melt aluminum cans, the direct customers of this induction heater would be the operator in the recycling process. This is the company that pays for the transporting company for delivering aluminum cans from the collection points to the melting plant. The operator also have to store the cans before they are melted, then melt them and distribute to material utilizers. There could be indirect customers for our product who could use this induction heater to melt or heat another type of material for many possible applications.

Page 3 of 11

The main benefit of melting aluminum cans using a compact heater like our product is that the melting can be done at collection points rather than at a single operational plant. Our induction heater significantly reduces the volume of empty cans, which reduces the cost of transportation and space required for storage before melting. Less volume means not as many trips are needed to transport the cans from the collection points to the melting venue. This can save money that the operator has to pay to the aluminum cans transporting companies. While that is the benefit during transport, the operator also can benefit by having solid blocks of aluminum delivered to their distribution venue rather than having large volumes of aluminum cans delivered. This saves space in their facilities where otherwise all the empty cans would have had to be stored before being melted. Meaning, the operator can save money on land space or rent cost that goes for the venue.

Our product is compact and safe to operate. Therefore, it can be operated at collection points without much space, and safely to the operator and surrounding. This would be a competitive advantage compared to the products currently available in the market for melting aluminum, because they are big and have to be operated in highly controlled environments for safety reasons. We expect to gain revenue by introducing and selling our product to operators of the aluminum recycling process around the world. There is also the possibility that the market for our product can be expanded to melting and heating other materials for additional revenue.

2) Product The business idea was covered in the previous topic but here the product is covered in more

detail. The technical aspects of the product are covered as well as everything that is provided by our company that is related to this product. The purpose of use and the benefits for the customer are already covered in the previous section but here the service for our product is presented.

Our induction heater design is somewhat simple, and it is supposed to be easy to manufacture and it also should be robust. The heater is easy to operate, and the advantage is that the melting process is fast. The aluminium cans are put inside the heater’s graphite crucible where the heating happens. After this, the heater is turned on and the aluminium will start to melt quickly after the start-up. When the cans have melted in the heater, the heater can be turned on and after a while the aluminium can be poured from the crucible in to wanted mould and the aluminium block is ready to be transported after some cooling time. The heater is easy to use, and it is also safe as its outside doesn’t heat to dangerous temperatures.

The induction heater consists of two parts: electromechanical part and power electronics. The electromechanics part has three main components. The graphite crucible is going to be the component that defines the actual size and melting volume of the heater. The crucible is the part where the aluminium is put during the melting process. The crucible is enclosed with insulation that is keeping the heat in the crucible. The insulation thickness depends on the size of the crucible used. On top of the insulation there is the induction coil which is made by using Litz wire or something that resembles it with its capabilities of conducting high currents without heating too much. The insulation between the coil and the crucible is there to insulate the about 700 degrees Celsius inside the insulation so that the used wire can operate without overheating. There has to be also a pouring mechanism where the crucible can be inclined so that the molten aluminium can be poured out of it. The power electronics are there to produce needed current and frequency into the coil in order to heat up the graphite with induction. The power electronics consist mainly of voltage rectifier and inverter. The rectifier is used to rectify the AC voltage that can be obtained from the grid. The inverter can then use this DC voltage in order to create the wanted waveform of AC to the coil. The

Page 4 of 11

components for power electronics are selected so that they are robust and high enough quality for this application to work for long time.

Our company’s product is the induction heater that comes as one compact package. However, this is not all that we provide to our customers. It is possible for our company to do the commissioning and test run for the induction heater once it is shipped to the site. This service can be purchased when making the order for the heater. Our company can also provide our customers a training session on how to operate the heater. Of course, the product is equipped with suitable warranty and our company will be responsible for the spare parts and maintenance of the heater during that time. Also, after the warranty period, we should be able to provide our customers with spare parts and maintenance possibilities for long period of time.

3) Market situation and competitors analysis Our customers are aluminium recycling companies, which include over 2000 companies

worldwide. The whole market worth is estimated to be around 1.2 billion Euros globally, but it’s notable that in some countries the aluminium beverage cans are separated from regular trash and not recycled individually as in Finland, making it more difficult for us to sell a small-scale melting solution, compared to larger separation and melting processes. Native market in Finland consists of only a few recycling companies, so it would make sense to target global market or at least the market within the EU. In addition, it’s possible to expand to alternative markets with our product as well, such as other material melting industries.

With these specifications, in Europe and the UK there are over 500 companies. Therefore, it would be justified to evaluate, that we would be able to get around 35 customers with 5000 can collection points. Estimated market sales would therefore be worth around 50 million Euros, which would correspond to around 4% market share. This estimation is a bit optimistic, but the market share would definitely be desired, considering how many of the companies are not a perfect fit to us due to recycling infrastructure or large quantities. Also, it has to be considered, that we are able to expand our market on demand.

The customer purchase decision process begins with a pitch or successful marketing, which makes a potential customer aware of the product, preferably supported with exact calculations considering percentual surplus derived from transportation and real-estate costs. After this, the potential customer has time to carefully consider their preferred recycling system, its infrastructure and the need for this investment. If the calculations conducted by the customer reveal a pleasant reimbursement schedule, and the savings are considered to be sufficient, first purchase occurs in example covering few of the busiest can collection locations. After this, the customer can choose to invest to more products, maximizing the surplus or be satisfied with their reduced need for transportation and real-estate. Later, reliability monitoring, service and maintenance amenities generate revenue to us from their preliminary investment.

Our most important competitors are companies providing solutions for melting aluminium, either with larger scale furnaces or induction heating solutions similar to ours. Indirect competitors include companies that provide recycling solutions for other materials, recycling machine manufacturers as well as transportation companies. Also, if we choose to proceed and evolve our product to metal melting industry, large hydraulic press manufacturers and other melting metal companies have to included to the competitor list.

Page 5 of 11

As competitors are divided widely between different industrial fields due to significant indirect competition, analyzing their relation and effect to our product is not exactly straightforward. The biggest inconvenience from our product is caused to the transportation companies, that are not competitors in terms of providing a similar product to potential client. However, they can adjust their pricing and therefore decrease the potential surplus the client could achieve from our product, making them perhaps the biggest competitor out there.

Another big competitors are aluminium or other metal foundries with large furnaces. They can provide a standardized product with high dimensions using molds to meet material utilizers demands to manufacture new beverage cans or other aluminium commodities. This competitor is more relevant on another part of the recycling process, but has to be considered a rival anyway.

Recycling machine manufacturers have already solved the issue we’re trying to solve by a simple hydraulic press at the collection point. This competitor is special in a sense, that it would be possible to be perceived as a client as well. Compared to hydraulic press technology, melting reduces the volume of aluminium even further, providing a clean and constant piece to be packed and shipped to recycling.

Other induction heating devices exist at a price point between 8 to 60 thousand dollars, so our plan is to be more competitive on the pricing. Afterall, the budget for this prototype is 500-1000 Euros, so with optimized parts and production, we should be able to compete with that price.

4) Intellectual property

The intellectual property law that is most relevant to protect our product is a patent. In order to make sure that we do not infringe the intellectual property rights of another inventor, we conducted a freedom to operate survey. In this analysis, we searched for patent literature for issued or pending patents relevant to our product on the European Patent Office online search. In our search for induction heaters relevant to cans, we were able to see that there are only patents for induction heaters that are used to heat beverages inside a beverage can in applications like vending machines. There are no patents for induction heating devices that are used in melting aluminum cans or melting aluminum in general using induction heating technology. However, there are induction heaters patented for heating metals in general that could be capable to melt aluminum. It does not specify a direct application like whether it can be used for melting aluminum cans. This search verified that there is no product currently protected by a patent that we might infringe by developing and selling this induction heating device commercially for melting aluminum beverage cans for recycling purposes.

Induction heating is a very common technology used in many applications nowadays. Induction heaters using litz wires as the source and a graphite crucible as the heating element like in our product is not to be found in the patent databases. Therefore, there is a possibility of patenting our design for the product. However, it is very unlikely the technology can be patented because induction heating could be considered obvious in the electrical engineering field as a counter-argument for the patent. Since there is no similar product to ours in the market already, trademarking our induction heater will make sure the quality of our brand can be protected and our product can be easily identified by customers if another competitor joins the market later with a similar design if we cannot get patent protection.

Page 6 of 11

The technology used in our product is well known in the electrical engineering and physics fields. Therefore, in that context we do not have anything to protect using trade secrets. Our design can be discovered by another party as well if they are interested in developing a product for a similar application. Therefore, patenting would protect our design better than keeping the design as a trade secret because it would save the cost of legal proceedings that are attached with keeping the secrecy of a trade secret as well as anyone could reverse engineer or rethink our design again and invent their own without having our parameters or test data. In conclusion, a design patent and a trademark for our induction heater would give the necessary protection to successfully place it in the market.

5) Product development and technology

Current situation of the project is a relatively small prototype capable of melting whole aluminium cans at 25 cl of volume or other small-scale scrap aluminium. Commercial products dimensions would differ to medium- and larger-scale devices, depending on whether the commercial product is aimed to industrial field or something more minor, like only beverage can recycling. However, the functionality of the project will remain the same, as it would on lower level application, so major issues or workload for larger-scale implementation shouldn’t be expected. Commercial product also has to be tested, verified and fitted to standards, as our product may undeniably be dangerous if it’s misused or it malfunctions.

Our rivals include the whole aluminium recycling industry, capable of large scale aluminium melting on large furnaces and melting the product to previously determined size and form, which is standardized by the material utilizers. There’s also indirect competition between companies providing recycling options for other materials, recycling machine manufacturers as well as transportation companies. In order of obtaining competitive advantage over our competitors, constant product development is required. Our technology is not only restricted to aluminium, but the device could easily be modified to melt other metals as well, with little or no modifications. Also, in order to be as agile as possible on the market, the previously mentioned sizing options have to be included to the catalog of products. The development requires significant expertise on power electronics, electronics and especially electromechanics. Also on product development point of view, a choice of temperature control could be added to the product. This enables a choice of temperature level. If for example only some heat treatment on lower temperature (such as can paint removal) was wished to be conducted or higher temperatures were wished to be reached, this could be achieved with a simple selection of output temperature.

To accomplish this product, we have a lot of options available to the future. First of all, it’s an alternative to sell the technology directly to bottle recycling device manufacturers as an alternative to hydraulic presses. Other option is to sell it directly to scrapyards, where the materials such as aluminium can be separated from other scrap metal and easily melted to blocks or desired forms. The first option doesn’t necessarily provide revenue for the company, but may provide a selling point as the surplus benefits the client.

Further investigation considering the average transportation prices as well as renting prices of real-estate should be conducted, in order to find the average amount of savings generated by our product. Right now, we’re working with estimated values and for efficient pitching purposes some real-world values would be more convincing. Perhaps a case study could be conducted for some individual customer, who agrees the study to be used as a selling point for potential new customers later. After the specific values are certain, they possess a powerful tool in terms of marketing.

Page 7 of 11

Other task for accomplishing this product is material and component optimization. On the prototype phase, we’re only considering the best and most suitable pieces of electronics etc, but while productizing our project, the cost and reliability become more and more crucial for generating revenue. A compromise for “good-enough” materials and components is a time-consuming task, which doesn’t end with the finished product, but has to be continued indefinitely, as new components and materials are introduced to market and old ones reach the end of their life.

Last, and the most important issue on the road of making this product reality is safety. As aluminium melts at 660 degrees Celsius, efficient casing, insulation and safety functions are vital while productizing the project. Even if everything is made according to safety standards, a fire hazard during the use of this product exists, so surrounding conditions should be carefully considered before using the device. This may also be perceived to be unattractive by the customer, so marketing have to be done right.

6) Conformance

The machine must meet the standard health and safety requirements set by the organizations. Therefore, the proper shape, size and high level of protection of our product is necessary to launch into the market. The following machine safety directive and standards are applicable for our product.

-Machinery Directive: 2006/42/EC Applicable Standard: EN 60204-1:2018 Applicable Standard: ISO 12100-1:2011

As we are dealing with electromagnetic system with high operating frequency, therefore, the product must meet the frequency disturbances standard. The following EMC directive and associated standard is applicable in order to reducing disturbances and enhancing immunity.

-Electromagnetic Compatibility (EMC) Directive:2014/30/EU Applicable standard: EN55011:2016

Under the following directive European Union (EU) set some tests and standard for electrical equipment designed for use within certain voltage limits. The following standard is particularly applicable for ensuring the safety during induction heating device installations.

-Low voltage Directive:2014/35/EU Applicable standard: EN 60519-2005

To meet all the standard set by the EC directives and make project output ready for the market the following improvements and modifications are required-

The product casing should be robust, well heat protective and does not allow heat conduction to the surroundings. As the device will deal with high current and generate high temperature, therefore, the high current and temperature tolerable materials and proper insulation will be used to ensure safety. To reduce the Electromagnetic Magnetic Interference (EMI) an EMI filter will be used. To collect the hot molten Aluminium a graphite crucible will be used. The induced current will be limit by proper grounding. An alarming system will be used if any damages or malfunctions occur inside the machine. An emergency automatic stop button will be used that can stop the machine quickly and provide safety both for the machine and the operating person. A

Page 8 of 11

monitoring screen can be used to show the temperature, current, frequency or other necessary data. A nameplate must be affixed to the device which will provide the rated voltage, current, frequency, KVA ratings etc. Signals and labels will be used to warn the worker about the danger associated with an induction heating device. A instructions manual will be provided with the device for proper use and installation.

7) SWOT-analysis In this section we present a SWOT-analysis for our induction heater product. The strengths,

weaknesses, opportunities and threats for our product are covered. The analysis can be divided into two sections: internal factors and external factors. The internal factors are the strengths and weaknesses of our product. These are mainly related to only our product are we are finding out what are its greatest strengths and weaknesses that can be considered during the development process. The opportunities and threats are the external factors that come outside of our product but must be considered carefully as for example the competitors can be considered as threats. Here the SWOT analysis is presented as a table where the success factors and risk factors are shown. Then a plan is presented to avoid the risks in product development.

Strengths Weaknesses

● Fast aluminium melting ● Compact size of the product ● Energy efficient ● Competitive price ● Easy usability

● The volume for aluminium is not as big as in larger melting furnaces

● The heater could pose a minor fire hazard

Opportunities Threats

● Need for recycling is increasing

● The product reduces the need for transportation

● The heater can be used for other materials with similar melting points as aluminium

● Companies don’t realize the benefits of our product

● Transportation companies compete with us with the prices

● Older technologies stay viable for long period of time

The strengths and opportunities have been covered well already in this document and it is

safe to say that our product has lots of strengths as an individual induction heater. Also, it has good opportunities to hit the market and to be valuable for the customers. There is certainly a place for our product in the market when going through the SWOT analysis.

Page 9 of 11

There are also some weaknesses and threats for our company’s induction heater device. And these should be taken into account during the product development. The main weakness is that the device is not going to be capable of melting the amounts of aluminium as the competitors’ large furnaces. Even though this can be count as a weakness, we have to think of it also as our strength. This product should be marketed as a product that can be viable option for smaller scale aluminium melting. The smaller size can also be advantageous if there is limited space available for the melting process. The other weakness is that the product can pose a minor fire hazard. This is because the heater is operating with high temperatures. The fire hazard can be avoided with proper use and proper protection and maintenance of the product. The installation place should also be suitable for the operation of the heater. All these aspects should be made clear for the customer so that the hazard can be prevented.

The threats for our product are mainly coming from the competition of the market. The companies might not actually realize the value of our product and want to stick to more traditional products such as melting furnaces. We have to be aware of the issue and do the marketing accordingly and well in order to gain the interest of our customers. The threat is also that the old technology lasts for really long time in operation. We have to be able to market our product to newer operators and to smaller recycling companies so that they can get the benefits of our product as early as possible. Also, the transporting companies can pose a slight threat to us as they can compete with our solution by lowering the prices and doing good contracts with operators. The same solution can be applied here which is good marketing.

Supplement: Distribution of work and learning outcomes

The making of this document was distributed equally by chapters among the team members.

The chapters ‘Summary’ and ‘Conformance’ were completed by Md Masum Billah while Yuvin Kokuhennadige completed chapters ‘Business Idea’, ‘Intellectual Property’ and main parts of this supplement chapter. ‘Product/Service’ section and ‘SWOT-analysis’ section were done by Jaakko Lind and Joni-Markus Hietanen wrote ‘Market situation and competitors analysis’ and ‘Product development and technology’ sections.

‘While writing the Business Idea chapter I was able to get an idea of what is important in the business perspective for our product. Me and my team was able to clearly understand our direct customers, competitors and how we should aim to generate revenue with our product. Writing the Intellectual Property chapter taught me different ways we can protect our product. The search for other similar products already patented led us to discover no similar products exists yet. This gives us the freedom to develop and market our product without fear of infringing someone else’s work. I was able to discover what components of our product is patentable and also how we can protect our brand using a trademark.’ - Yuvin Kokuhennadige

‘Working on the summary chapter gave me an opportunity to understand the overall business aspects of our product. I was able to differentiate the competitive advantages of our product. I found the customer demand in the recycling industry and how can a product satisfy their needs. In addition, I got the ideas about the market size and competitions, our scopes and market entry strategy. Writing conformance chapter taught me that making a product is not sufficient, but the product must meet the standard set by the different organizations. I was able to find out which directives and standards is required for our products to successfully launch it into the market. I understood which improvements and modification require for our product to meet the global benchmark.’ - Md Masum Billah

Page 10 of 11

‘The market investigation revealed a lot of options and potential decisions to be made considering our product. The potential is there, but competition is also fierce. In order to be relevant within today’s markets, one has to possess a lot of preliminary information and also be capable of innovation as well as compromise. Competition is also self-defeating without appropriate product development, which must be constant, cutting-edge and flexible. Also, the road for productizing a prototype takes up a lot of minor, yet mandatory steps, which I personally had not considered before.’ - Joni-Markus Hietanen

‘As I was working on the ‘Product/Service topic, I was able to think about the whole product and the usage of it. This was not too hard as we have been working on this project for quite a while already. However, I thought about the other things our company should provide to the customer alongside the actual product. I instantly thought about the services that are usually provided with the commercial products as I have been working in service department in ABB before. Also, I got a good reminder how to prepare a SWOT analysis. The hardest part here was to find the weaknesses and threats of our product. After finding some, I tried to figure out how to prevent those. This was good learning experience’ - Jaakko Lind

Page 11 of 11