precision variable frequency drive may 07-13
DESCRIPTION
Precision Variable Frequency Drive May 07-13. Client: Jim Walker Advisor: Dr. Ajjarapu Team Members: Matt Shriver Jason Kilzer Nick Nation Dave Reinhardt April 24, 2007. Presentation Outline. Introductory Materials (Nick) Project Approach & Design (Jason) Testing and Implementation (Matt) - PowerPoint PPT PresentationTRANSCRIPT
Precision Variable Frequency DriveMay 07-13
Client: Jim WalkerAdvisor: Dr. Ajjarapu
Team Members:Matt ShriverJason KilzerNick Nation
Dave Reinhardt
April 24, 2007
Presentation Outline
Introductory Materials (Nick) Project Approach & Design (Jason) Testing and Implementation (Matt) Closing Materials (Dave)
The Prototype
List of Definitions
VFD: Variable Frequency Drive PWM: Pulse Width Modulation IGBT: Insulated Gate Bipolar Transistor
Acknowledgements
Faculty advisor Dr. Ajjarapu Client Jim Walker Graduate Students
Ryan Konopinski Sheng Yang
General Problem Statement
The speed control of an AC synchronous motor.
The synchronous motor and the subsequent drive mechanism do not always keep the correct speed.
A method is needed to control the frequency that is delivered to the synchronous motor.
Solution
A precision variable frequency drive will allow the user to manually change the operating frequency.
Operating Environment
Indoors No extreme conditions Near power outlet
Intended Use
As a drive for a low power AC synchronous electric motor.
This drive was not considered to be used on any other type of electric motor except for a synchronous design.
This drive shall not be used to power any control circuits.
Intended Users
Anyone who desires precise control over a small AC synchronous motor.
An owner of a turntable who needs better control over the speed of their turntable.
No technical knowledge will be required to operate the Precision VFD.
Assumptions
Constant linkage –An increase in motor speed by a certain factor will result in an increase in the speed of the turntable by the same factor.
Plug – the power cord from the record player can plug into a standard three pronged outlet.
Limitations
Minimum Power Output: 75 W Output Frequency Range: 58-62 Hz Frequency Precision: 0.001 Hz Frequency Stability: < ± 0.01 % 12” by 12” by 6” size limitation Cost less than $350
Expected End Product
Precision variable frequency drive Portable strobe system One-page quick users guide Circuit diagrams and parts list
Project Approach
Present Accomplishments
Research technologies (100%) Simulate entire system (100%) Purchase components (100%) Build components (85%) Test components (70%) Build entire system (70%)
Approaches Considered
Crystal Oscillator No prior knowledgeFrequency range was too high
Reverse Engineer(VPI’s Synchronous Drive System)
Difficulty getting hands on productMany partsLittle understanding of parts
Pulse Width Modulation
One group member familiarPrior understanding of partsCould handle low frequencies
Project Definition Activities
Develop a VFD that will provide a precise frequency that can be changed.
A strobe light will also be included to measure the RPM of the electric motor.
Research Activities (1 of 2)
Pulse Width Modulation Needs small signal variable frequency
sine wave Need small signal triangle wave Comparator produce pulses from
comparison of sine and triangle wave PWM would create the control signals
for the IGBT bridge
Research Activities (2 of 2)
IGBT Bridge Provides power separation between
PWM circuits and power supply circuitry Generates pulses
Precision Variable Frequency Drive
Ready to use design Delivers precise frequency control for low
power AC synchronous motors Strobe light included to measure RPM of
motor
Design
Pulse Width Modulation Circuits IGBT Bridge and Filter Circuits Power Supply Circuits
Overall Block Diagram (1 of 2)
Sine Wave
Triangle Wave
Comparator
IGBT Bridge
Inverter
Overall Block Diagram (2 of 2)
IGBT Bridge
Low Pass Filter
Frequency Counter
OutputTransformer
Pulse Width Modulation Circuits
Sine Waveform (Variable
Frequency)
Comparator
Triangle Waveform
Inverter
IGBT Bridge and Low Pass Filter
IGBT Bridge
Low Pass Filter
Power Supply Components
Astrodyne Power Supply (PT-45C) Input: 120 VAC Outputs: +/-15V, +5V
Filament Transformer Primary Winding: 117V Secondary Winding: 8V
Testing and Implementation
PWM Circuits
InvertedGate SignalU2
uA741
3
2
74
6
1
5+
-
V+V-
OUT
OS1
OS2
Comparator
-Vcc
V1
TD = 1p
TF = 249.99999uPW = 1pPER = .5m
V1 = .5
TR = 249.99999u
V2 = -.5
Triangle Wave0
Inverter
+Vcc
V2
FREQ = 60VAMPL = .375VOFF = 0
00
U3
uA741
3
2
74
6
1
5+
-
V+V-
OUT
OS1
OS2
+Vcc
-Vcc
0
V35Vdc
Sine Wave
-Vcc
+Vcc
V4-5Vdc
0
Gate Signal
Comparator Input/Output Waveforms
Inverter Input/Output Waveforms
IGBT Bridge and Low Pass Filter
Filter Input/Output Waveforms
Input and Output Waveforms of the Low Pass Filter
Implementation and Testing
Function generator chips Amplifiers Comparator and Inverter IGBT’s Filter Strobe light system
Sine & Triangle Generator Chips
Built and tested on breadboard
Amplifiers, Comparator, and Inverter Circuits
Built and tested on breadboard
Comparator Testing
Comparator Chips UA741 Op Amp LM319N High Speed Comparator
Sources Lab Function Generators Function Generator Chips
IGBT Bridge
build and test on breadboard
IGBT Bridge Testing
Design overlooked need for delay circuitry
Tried multiple timing circuits NE555 Timer Circuit UA741 Op Amp Circuit
Strobe Light System
Strobe Light Schematic
Closing Material
Resources
Item W/O Labor With Labor
Miscellaneous Parts & Materials $20.00 $20.00
Device Components $66.90 $66.90
Project/Poster Printing $0.00 $0.00
Subtotal $86.90 $86.90
Labor at $15.00 per hour:
Reinhardt, Dave, 142 hrs $2,130.00
Kilzer, Jason, 166 hrs $2,490.00
Nation, Nick, 148.5 hrs $2,227.50
Shriver, Matt, 245 hrs $3,675.00
Subtotal $10,522.50
Total $86.90 $ 10,609.40
Schedule
Detailed Gantt Chart
Deadline Schedule
Deadlines Schedule
Project Evaluation (1 of 2)
MilestoneDegree of
Achievement Comments
1. PVFD Project partially met Some milestones were fully achieved while others were not
A. Produce PVFD partially met Some of the items below were attained with others only partially attained or not at all
1) Develop Design for PVFD fully met The design met all technical requirements, when simulation test were complete
2) Simulation of PVFD partially met Full simulation was completed. However two programs were needed to complete simulation
3) Implementation of PVFD partially met The design was completely implemented into a prototype
4) Technical requirements satisfied by prototype partially met See items below.
a) Provide minimum power output of 75 W fully met
b) Output continuously selectable between 58 and 62 Hz exceeded Output is selectable between 57.5 and 62.5 Hz.
c) Short-term stability less that 0.01% not attempted Client not concerned
d) Frequency display accurate to 0.001 Hz not met PVFD has a frequency display accurate to 0.01 Hz.
B. Portable strobe system partially met
Project Evaluation (2 of 2)
MilestonesRelative
ImportanceEvaluation
ScoreResultant
ScoreProblem Definition 15% 100% 15.0
Research 10% 90% 9.0
Technology Selection 5% 100% 5.0
End Product Design 15% 70% 10.5
Prototype Implementation 15% 60% 9.0
End Product Testing 10% 50% 5.0
End Product Documentation 5% 70% 3.5
Project Reviews 5% 90% 4.5
Project Reporting 10% 100% 10.0
End Product Demonstration 10% 50% 5.0
Total 100% 76.5
Commercialization
Not produced for commercialization Precision variable frequency drive
could be implemented for much less than current market price (~$250)
Additional Work
Resolve comparator issues Resolve IGBT issues Combine Precision VFD and strobe
light system into one product Include feedback loop for total
autonomy
Lessons Learned (1 of 2)
What did not go well•Problem definition and planning (needed a new plan when we started implementing)•Having everyone on the same page (team members, advisor, vendor)
What went well•Design/Simulation of project•Testing
Lessons Learned (2 of 2)
Technical•Implement and test one component at a time•Keep it simple•Comparator troubleshooting•IGBT implementation
Non-technical•Should have planned a lot more time for implementation•Everyone must be on the same page•Have a good plan to start
Risk and Risk Management
Potential Risks Planned Management
Cost (Over Budget)
The group was given $300 ($150 - senior design; $150 - client). If the cost was less than $75 over budget the group members would chip in some money.
Lazy Group Member
E-mails would be sent detailing group members responsibility along with due date.
Design does not meet Client’s specifications
The client would be contacted and the lack of performance would be discussed. Input for client will determine where the project is to go.
Unanticipated Risks
Unanticipated Risks Attempts to Manage Risks
Strobe light difficultyThe group found a simple "Do It Yourself" strobe light design with complete parts list and schematics.
Comparator not working
The group sought advice from advisor, graduate students, and other faculty.
Difficulty of producing output voltage of 120 VAC
Planned to use a transformer to step-up the voltage.
Closing Summary
An incomplete prototype was produced due to difficulties with the comparator and the IGBT bridge.
Estimated final product could be commercialized and sold for $250.
Demonstration and Questions