design of a solar power management system for an experimental uav

Design of a Solar PowerManagement System for anExperimental UAV

JAW-KUEN SHIAU, Member, IEEE

DER-MING MA

PIN-YING YANG

GENG-FENG WANG

JHIJ HUA GONGTamkang University

The design of a solar power management system (SPMS) for

an experimental unmanned aerial vehicle (UAV) is summarized.

The system will provide power required for the on-board

electronic systems on the UAV. The power management system

mainly consists of the maximum power point tracking (MPPT),

the battery management, and the power conversion stages. The

MPPT stage attempts to obtain the maximum power available

from the solar cell panels. The battery management stage

monitors and controls the charge and discharge processes of

the Li-Ion polymer battery modules. The last stage is for power

conversion that consists of dc/dc synchronous buck converters to

generate +5 V and +12 V powers for the on-board computers

and other electronic circuitries.

Manuscript received January 24, 2007; revised February 18 andJuly 10, 2008; released for publication August 5, 2008.

IEEE Log No. T-AES/45/4/935097.

Refereeing of this contribution was handled by W. Polivka.

This research was supported by the National Science Council,Taiwan, Republic of China, under Grant NSC94-2212-E-032-005.

Authors’ current addresses: J-K. Shiau, D-M. Ma, P-Y. Yang, Dept.of Aerospace Engineering, Tamkang University, 151 Ying-ChuanRoad, Tamsui, 25137 Taiwan, E-mail: ([email protected]);G-F. Wang, Formosa Plastic Associate Company, Taiwan; J-H.Gong, Lite-ON Technology Corporation Company, Taipei, Taiwan.

0018-9251/09/$26.00 c° 2009 IEEE

I. INTRODUCTION

Solar power, without a doubt, is the cleanestenergy in the world. Usages of solar energy arewidespread in industry, commercial, and militaryapplications [1—5]. It will gradually become one ofthe primary energy supply resources in the future.This paper discusses the design of a solar powermanagement system (SPMS) for an experimentalunmanned aerial vehicle (UAV). Solar-poweredUAV possesses broad research value for technologydevelopment and commercial applications. Asolar-powered UAV could in principle stay overheadindefinitely as long as it had a proper energy-storagesystem to keep it flying at night. The design ofthe power management system for such aircraft ischallenging due to possible rapid attitude changesduring maneuvers.The solar power is not an ideal energy source. The

solar cell panels can only generate power at certaintimes of the day. So the most important considerationfor using the solar power is to maximize the utilityof the solar power while it is available. To ensurethat the maximum available power is received fromthe solar panel, a certain type of maximum powerpoint tracking (MPPT) algorithm [6—11] is usuallyincorporated into the SPMS. A comparative study ofMPPT algorithms that could be easily implementedin a low-cost microcontroller is reported in [12]. Theincremental conductance algorithm [6] can efficientlytrack the maximum power point under rapidlychanging atmospheric conditions. The efficiency ofthe incremental conductance algorithm, as reported in[12], can be in excess of 97%. In this research, weimplement the incremental conductance algorithmand use the natural sunlight as the irradiance sourceto conduct the MPPT test.Since solar cells can only generate power at certain

times of the day, a storage element is required inall solar power systems. The most common formof the energy storage for the stand alone solarpower system is battery technology. The basicfunctions of the battery management are to controlthe charge/discharge of the battery, to protect thebattery from damage, to prolong the life of the battery,and to maintain the battery in a state to fulfill thefunctional requirements. Battery management systemsfor a solar power system with lead acid battery arediscussed in [13], [14]. Although the lead acid iswidely used in the industry, it is not considered tobe suitable for UAV application when weight andvolumetric capacity are taken into account. Thelithium-ion polymer battery is selected for this UAVapplication study. The dynamic lithium-ion batterymodels have been extensively studied recently asreported in [15], [16] and the references therein.Many applications require knowledge of the stateof charge (SOC) [17] of the battery for providing

1350 IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS VOL. 45, NO. 4 OCTOBER 2009

the user with an indication of the capacity left inthe battery. This is important for optimizing thecharging process. Voltage and current based SOCestimation can provide a rough indication of the SOCof a battery, but for more precision, other factorssuch as amplitude of the discharging current, ageof the battery, environment factors, and operatinghistory of the battery must be taken into account.Correction for these factors can only be accomplishedwith complex software by building a battery modelto replicate the battery characteristics. In [17] acharge measurement circuit is designed to improvethe SOC estimation. It shows that the accuracyof the required charge flow measurements can begreatly improved by using a voltage to frequencyconverter in conjunction with a digital counter tointegrate the measured battery current. In manyapplications, multi-cell battery chains are requiredto provide a higher operation voltage or power. Acharge equalization technique that utilizes a simpleisolated dc/dc converter with a capacitive output filteralong with a multi-winding transformer is proposedin [18]. In [19] a battery management system consistsof a number of smart battery modules each of whichprovides battery equalization, monitoring, and batteryprotection to a string of battery cells. Complex chargeequalization circuitries are not considered to besuitable for this particular application due to space,weight, and power consumption considerations. Thebattery management system proposed in this designis different from those presented in [13], [14], and[19]. It includes an auto-ranging power converter, acharge controller, and lithium battery modules. Themicrocontroller-based charge controller is designed tocontrol the auto-ranging power converter to maximizethe utility of the solar power. Two battery moduleswith one serving as the charging module and theother as the discharging module are used in thisdesign.In this research, we focus on the design evaluation

of a SPMS for an experimental UAV application. Thebattery management has to handle the rapid voltagevariations due to attitude changes during maneuvers.To gain the quantitative idea of power variationson rapid changing of the sunlight incident angle, aservo-motor-driven experimental test bed is developedto support the evaluation. Test results on the voltageand power variations are presented and discussed.The test results provide a good reference for thesizing, power, weight, optimal flight path design, andperformance consideration for the development of afully solar powered UAV.Design and function validation of an SPMS are

the primary purpose of this research. Therefore, theobtained solar power is used to power some certainon-board computers only. Power required for thepropulsion and control systems is not included in thedesign. A much larger solar cell panel will be needed

Fig. 1. Configuration of SPMS.

Fig. 2. Prototype of SPMS.

to power the complete system. The SPMS consideredin this research consists of three stages. The firststage is the solar cell panels and the maximum powertracker. The second stage is the battery managementsystem. The last stage is the power conversionstage that includes dc/dc synchronous buck powerconverters [20] to provide reliable +5 V and +12 Vpower sources for on-board electronic systems.

II. SYSTEM OVERVIEW

The SPMS is designed to obtain electric energyfrom the solar system and to make the requiredpower available for the on-board computers and otherelectronic circuitries for an experimental UAV. Theoverall system structure is depicted in Fig. 1. Thefunction validated prototype of the system is shownin Fig. 2.In this research, we use mono-crystalline solar

cells as the power source. To accommodate theaircraft configuration, the solar cell panels are dividedinto three panels, namely left wing, right wing, andfuselage panels. Pictures of these solar cell panels areshown in Fig. 3. Under a standard test condition, thesolar panels will generate a maximum power of up toaround 57.2 W. The maximum power point voltageand current are around 30 V and 1.91 A, respectively.The electric characteristics of each panel are list inTables I—III.As shown in Fig. 1, the SPMS system is divided

into three stages. The first stage, MPPT, attempts toincrease the efficiency of the solar cells to obtain themaximum power available from the solar cell panels.The second stage, battery management, monitors andcontrols the energy storage and delivery of the solarpower drawn from the solar cell panels. The thirdstage, power conversion, converts input voltage to+5 V and +12 V for the on-board electronics. Thefunctional considerations and designs for each stageare discussed in the following sections.

SHIAU ET AL.: DESIGN OF A SOLAR POWER MANAGEMENT SYSTEM FOR AN EXPERIMENTAL UAV 1351

Fig. 3. Left wing panel (top), fuselage panel (center), right wingpanel (bottom).

TABLE ILeft Wing Panel

Typical peak power 23.23 WVoltage at peak power 30.08 VCurrent at peak power 0.772 AShort-circuit current 0.839 AOpen-circuit voltage 37.66 V

TABLE IIRight Wing Panel


TABLE IIIFuselage Panel


III. MAXIMUM POWER POINT TRACKING

The electric power generated from the solar cellsdepends on the temperature and the solar radiationconditions and the load electric characteristics. MPPTis often used in photovoltaic systems to maximizethe solar panel output power, irrespective of thetemperature and irradiation conditions and of theload electrical characteristics. The solar cell is a

Fig. 4. Equivalent circuit of solar cell.

nonlinear device and can be represented as a currentsource model as shown in Fig. 4 [21]. Where Iphis the equivalent current source, Rsh and Rs are theequivalent shunt and series resistance of the material,and D is the P-N junction diode.The shunt resistance Rsh is much greater than the

series resistance Rs. Therefore, the output current ILcan be represented as [22]

IL = Iph¡ ID = Iph¡ IO·expμqVLKTA

¶¡ 1¸

(1)

where q is the charge of an electron, K is theBoltzmann’s constant, A is the ideality factor of theP-N junction, T is the solar cell temperature (±K),and Io is the reverse saturation current. The reversesaturation current is [22]

Io = Irr

·T

Tr

¸3exp

·qEGAPKT

μ1Tr¡ 1T

¶¸(2)

where Tr is the reference temperature, Irr is thesaturation current at Tr, EGAP is the band-gap energyof the semiconductor used in the solar cell. The lightgenerated current source Iph is

Iph = [Isso+Ki(T¡Tr)]Si100

(3)

where Isso is the short-circuit current at referencetemperature, Ki is the short-circuit current temperaturecoefficient, Si is the insolation in mW/cm

2. So theoutput power from the solar cell can be expressed as

P = ILVL = IphVL¡ IoVL·expμqVLKTA

¶¡ 1¸: (4)

Output current and power at different insolations anddifferent temperatures for this particular solar powerpanel are shown in Fig. 5.Each curve has a maximum power point as

indicated in Fig. 5, which is the optimal operatingpoint for the efficient use of the solar cells at thatparticular operating condition. In order to efficientlyuse the solar cells, we attempt to force the solar cellsto operate at the maximum power point throughsome mechanism called the MPPT. To clearly explainthe operation of the MPPT mechanism, we pick anoperating curve and redraw the characteristic curve inFig. 6. Cleary, at maximum power point ¢P=¢V = 0.We decrease the output voltage if ¢P=¢V < 0, andincrease output voltage while ¢P=¢V > 0.


Fig. 5. Current and power characteristics of solar cell panels.

Fig. 6. Characteristic curve of solar cell.

Fig. 7. MPPT system.

The MPPT system consists of a pulsewidthmodulator (PWM), a MOSFET driver, a dc/dcbuck power converter, and a micro-controller(PIC18F452 in this design). The block diagram ofthe MPPT system is shown in Fig. 7. The mainidea is to continuously adjust the voltage at theload terminal by controlling the duty cycle of thePWM regulator. A commonly used MPPT algorithmincludes perturbation and observation method [8],incremental conductance technique [6, 9], andfuzzy logics [7, 10, 11]. In this design, we use theincremental conductance technique to implement theMTTP function. Development of the MPPT algorithmis not within the scope of our design. We are notattempting to compare the differences among theMPPT algorithms. In order to provide sufficientcurrent needed for controlling the switching transistor

Fig. 8. MOSFET driver.

Fig. 9. Functional block diagram of battery management system.

and limiting the drain-source voltage of the switchingtransistor, the MOSFET driver circuit proposed in [23]is adapted for this design. The driver circuit is shownin Fig. 8. This driver circuit is also used in the secondstage for battery management.

IV. BATTERY MANAGEMENT

The battery management system monitors andcontrols the storage and delivery of the energy drawnfrom the solar panels. The system block diagram ofthe battery management system is shown in Fig. 9.The system consists of three major subsystems,namely the lithium battery modules, an auto-rangingpower converter, and a charge controller. The inputpower of the battery management system comes fromthe output of the MPPT system. The output of thebattery management system supplies the requiredpower to the power conversion system (the last stageof the power management system) to provide all therequired power for the on-board computers and otherelectronic circuitries.The battery modules selected in this system

are Lithium ion (Li-Ion) polymer rechargeablebattery (HECELL company, battery model:H6849D5-4800 mAh). A battery submodule consistsof three battery cells, the nominal voltage is 11.1 V.The battery management system contains two batterymodules. Each module consists of four submodules,arranged as shown in Fig. 10. It has a nominal voltage


Fig. 10. Construction of battery module.

of 22.2 V with 9600 mAh capability. The batterymodules and relay control structure are depicted inFig. 11. Initially, batteries 5—8 form as the dischargingmodule while batteries 1—4 serve as the chargingmodule. As shown in Fig. 11, to form the dischargemodule, the 4-pole relay S10 is closed and relays S5,S6, S7, and S8 are open.Fig. 12 is the charging and discharging control

circuitry for the Li-ion batteries. In charging theLi-ion battery, the battery is charged at a constantcurrent until the battery voltage reaches the maximumvoltage limit. The circuit then switches to voltageregulation, allowing the current to taper to lowervalues. Accurate voltage regulation is necessary toput the maximum safe charge into the battery. Inconstant current mode, we keep the voltage V1 at aconstant voltage through controlling the pulsewidthof the PWM regulator in the auto-ranging powerconverter. We adjust the pulsewidth of the PWMregulator to maintain V2 at a constant level while inconstant voltage mode. To charge submodule 1, weclose the relay S1 with relays S2 and S9 open. On theother hand, we need to close the relay S2 and openthe relays S1 and S9 to charge the battery submodule2. The constant current/constant voltage chargingwaveform is shown in Fig. 13. In discharging mode,we close the relay S9 and open the relays S1 and S2.The discharge waveform is shown in Fig. 14.The control circuitry for maintaining the constant

voltage or constant current charging for a particularbattery submodule is shown in Fig. 15. The chargecurrent for constant current charging mode is

I =VFRS

μR2 +R3

R1 +R2 +R3

¶: (5)

Fig. 11. Li-ion battery modules and relay control structure.

Fig. 12. Charging/discharging circuitry for Li-ion battery.

Fig. 13. Constant current/constant voltage charging waveform.

Fig. 14. Li-ion battery discharging waveform.

The resistance of RS connected to the battery forconstant current control is 0:1 −. The voltage VF tothe charge controller for constant current regulation


Fig. 15. Constant current/voltage control circuitry.

is maintained at 2.5 V through the charge controllerand the PWM regulation loop. If R1 = 100 k−, R2 =1:96 k−, and R3 = 2:2 k− are selected, the chargecurrent I in (5) is maintained at 1 A. There are atotal of 8 battery submodules in the system. The 8-1multiplexer is used to select the battery to charge.The auto-ranging power converter consists of a

dc/dc power converter and a charge regulator. Thepower converter selected in this system is a bucktype power converter, the same as the one for theMPPT stage, due to the fact that most of the timethe voltage at the output of the MTTP stage is higherthan the required charge voltage. The charge regulatoris a microcontroller-controlled PWM regulator. Thecharge voltage at the output of the power converteris controlled by continuously adjusting the dutycycle of the PWM pulse. It should be noted thateven most of the time the voltage at the input to theconverter is higher than the battery charge voltage(12.6 V in this case), in some cases, such as whensunlight to the solar panel is shaded or the incidentangle is too high, the voltage might be lower thanthe required charge voltage. There are several ways tocope with this issue. The simplest way is to terminatethe charging process once the input voltage is downbelow a predetermined threshold, 14 V for instance.This, however, leads to a waste of the solar power.The better approach is to put a low voltage constraintin the MPPT algorithm. That is, maintain the MPPToutput voltage at 14 V if it is lower than this limit. Wepropose that both approaches should be implemented.Yet another approach would be to design a buck-boosttype power converter to deal with the voltagevariations. To provide auto-ranging capability forbattery charging, the buck-boost converter wouldnot be just providing the regulation function only;it would be a micro-processor controlled powerconverter. Micro-processor controlled buck-boostpower converter is more complicated than the bucktype converter. However, it is worth implementingthe buck-boost converter to provide the auto-rangingcapability for a larger solar power system to maximizethe utility of the solar power.The primary function of the charger controller

is to perform the monitoring and charge/discharge

control of the batteries. The Microchip PIC18F4515microcontroller is selected to do the required tasks.The charge controller is able to measure the voltageand current of each individual battery submodule.The charge controller continuously monitors theoperating condition of the batteries to prevent themfrom becoming overstressed. The constant currentfollowed by constant voltage scheme is implementedfor the charging process. To charge a battery, thevoltage of the battery is checked first. This is theeasiest way to determine the SOC if the current hasremained at zero long enough for the voltage tostabilize. If the voltage is within the rechargeablerange, greater than 9 V and less than 12.6 V in thisdesign, constant current charging is initiated. Theconstant voltage charging will be engaged once thecharge voltage reaches 12.6 V. Note that there is atotal voltage drop of about 0.3 V across the relay andthe current sensing resistor RS . The constant voltagecharging is a slow charging process. The chargingcurrent during the constant voltage mode is muchsmaller than the charging current during the constantcurrent period. The voltage drops across the relay andRS are insignificant in the constant voltage chargingstate due to small charging current. The chargingprocess will be terminated when the battery voltagereaches the voltage limit 12.6 V. The terminal voltageof the discharging module is checked periodically toensure the health of the batteries. Since two batterysubmodules are connected in series to provide therequired power for the load, the discharging voltageis kept at about 22.2 V. This voltage can be used as anindication of the discharging state of the battery andcan be used to determine the cutoff point. To avoidfully discharging the battery cells, a discharge warningis set when the voltage reduces 19 V. At this point,we exchange the charging and the discharging batterymodules to continue to supply the required power.Space and weight are one of the strict limitations

for designing a power management system forUAV application. Complex charge equalizationcircuitries which usually involve switches, currentsensors, transformers, dc/dc converters, etc., are notimplemented in this particular design due to space,weight, and power consumption considerations.However, it should be taken into consideration whendesigning a fully solar powered UAV with muchlarger solar cell panels and equipment installationspace.

V. POWER CONVERSION

The power conversion system converts the voltagelevel from 22.2 V at the battery end to +5 V and+12 V for providing the required power to theon-board computers and all other electronic circuitries.In particular, the +12 V power source is used todrive the relay circuitries in the battery management


Fig. 16. Synchronous buck power converter.

Fig. 17. (a) Q1 on, Q2 off. (b) Q2 on, Q1 off.

Fig. 18. Experimental test bed.

system. The simplified functional block diagram ofthe synchronous buck converter used in this design isshown in Fig. 16. It uses two N-type MOSFETs Q1and Q2 to control the energy flow from source to theload. Synchronous buck controller used in this designis TPS40055 [24]. Detail design guidelines can befound in the data sheets. The simplified circuit for theinductor charging cycle is shown in Fig. 17(a). In thisstate, the MOSFET Q1 is conducted and Q2 is turnedoff. In inductor discharging state, the operation isreversed as shown in Fig. 17(b). Stability analysis andfeedback controller design for this synchronous buckpower converter is quite standard and is not addressedfurther in this paper. For detail design proceduresplease refer to [24]. In this system, two converters aredesigned for +5 V and +12 V power sources.

VI. EXPERIMENTS AND RESULTS

In order to evaluate the design of power acquiringfrom the solar cells and obtain some quantitativeidea of power variations on rapid changing of theincident angle of the sunlight, a servo-motor-drivenexperimental test bed is developed to support theevaluation. The block diagram of the experimentaltest bed is shown in Fig. 18. We control the sunlightincident angle by rotating the test bed. During testing,we record the rotating angle of the test bed andvoltage and current drawn from the solar cells.

Fig. 19. MPPT experiment setup.

Fig. 20. Test results on 04/22/2006 (at 11:50).


The physical setup for the MPPT experimentis shown in Fig. 19. The results of the experimentconducted on 22 April 2006 at Tamkang Universityare shown in Figs. 20 and 21. The results show thehistory of the measured voltage, current, power,and incident angle. In this work, MPPT tests wereconducted with the incremental conductance MPPT


algorithm using natural sunlight as the irradiancesource. The efficiency of the incremental conductancealgorithm has been reported to be as high as 89.9%and 97.4% in [6] and [12], respectively. Temperaturemeasured on the solar cell panel is about 50±C whilethe outdoor air temperature is 27±C. Fig. 20 showsthe evolution of the MPPT with partial shading ofthe solar cell panel. Fig. 21 shows the results of therapid changes of the power when it suddenly (in about1 min) became clouded.Figs. 22—24 show the experimental results that

were conducted on September 1, 2006; the sky isrelatively clear with 32±C outdoor air temperature.The temperature measured on the solar cell panel isabout 70±C. The power we obtained is lower than thepower that we got at the previous experiment due topanel temperature changes. In this experiment, wealso vary the incident angle (Fig. 23) of the sunlightby rotating the solar cell panel up to §45 deg withan increment of 5 deg and stay at the same positionfor 10 s. Three different loads (5 −, 10 −, and 15 −)are used to conduct the test. The results show thatthe solar power changes with the incident anglecorrectly. To verify the extraction of the maximumpower, we take the power at zero degree incidentangles as the reference and times cosμ with μ varyingaccording to the experiment setup to generate asimulated maximum power. Note that we assumethe sunlight irradiance keeps the same during theexperimental cycle (about 6 min). Then we comparethis simulated maximum power to the measuredmaximum power. The results show that the systemstill tracks the maximum power point quite well asshown in Fig. 24. In Fig. 24, PSIM represents thesimulated maximum power taking the power at 0incident angle as the reference then times cosμ. Thesunlight irradiance may vary during the test. In asteady sunlight irradiance condition, as shown inFig. 24 with 10 − load, the maximum power almostperfectly matches the simulated power.The test results show that when the sunlight

incident angle varies from 0 to 45 deg, the powerdrawn from the solar cells depends on the loadconditions and can have a reduction of up to some30%. This implies that the changes of aircraft attitudewill directly affect the power obtained from the solarsystem. This in turn will limit the pitch and rollangles of the aircraft maneuver and must be taken intoconsideration for optimal flight path design. The testresults also provide a good reference for the sizing,power, weight, and performance consideration for thedevelopment of a fully solar powered UAV.

VII. CONCLUSIONS

This paper discusses the design of an SPMS.The system consists of solar power panels shaped toaccommodate aircraft configuration, an MPPT system


Fig. 23. Power variations due to changes of sunlight incidentangles. (15 − load starts from 12:10; 10 − load starts from 12:19;

5 − load starts from 12:42).

Fig. 24. Comparison of maximum power to simulated maximumpower.


to increase operating efficiency of the solar cells, abattery management system to monitor and control theenergy storage and delivery, and a power conversionsystem to convert the power drawn from the solarsystem to the using systems. An experiment systemfor MPPT evaluation is also developed to support thesystem design. The results will be used to improvethe solar powered UAV configuration, propulsion,and performance designs. Designs to incorporate thepropulsion power requirement to support the trulysolar powered UAV are underway. In the new design,the SPMS will manage the entire power requirementfor up to 600 W to support the UAV operation.The power bus structure provided in this paper

contains three power conversion stages in cascade.The power efficiency of the overall system is thecombination of the efficiency of all of the three stages.This structure is useful for low power applicationssuch as UAV systems where we need to deal withpossible rapid changes of atmospheric condition. Thisstructure, however, may not be suitable for high powersystems such as satellites power bus structure.

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Jaw-Kuen Shiau (M’99) received the B.S. and M.S. degrees in electricalengineering and electronic engineering from Chung Yuan Christian University,Taiwan, in 1981 and 1983, respectively. He received the Ph.D. degree in electricalengineering from Rensselaer Polytechnic Institute, Troy, NY, in 1995.Dr. Shiau had worked in industry and government laboratory on high

performance fighter aircraft flight control system design for over 10 years. Since1997, he has been with the Department of Aerospace Engineering, TamkangUniversity, Tamsui, Taiwan. His research interests include robust control, flightcontrol system design, avionics system design and integration for UAV and solarpower management system for UAV.

Der-Ming Ma received the B.S. and M.S. degrees in aeronautical engineeringfrom Chung Cheng Institute of Science and Technology, Taiwan. In 1988, hereceived the Ph.D. degree in aerospace engineering from the University ofMichigan, Ann Arbor.He is presently Associate Professor of the Department of Aerospace

Engineering, Tamkang University, Taiwan. He currently works on system designof solar-powered UAV, optimal atmospheric flight trajectories, and guidance,navigation and control.

Pin-Ying Yang received the B.S. and M.S. degrees in aerospace engineering fromTamkang University, Tamsui, Taiwan, in 2003 and 2007, respectively.His research interests include power electronics, solar power management

system, and applications of embedded systems.

[24] Texas Instruments, Inc.Wide-input synchronous buck converter TPS40054,TPS4055, TPS40057.Datasheet, Rev D, June 2005.


Geng-Feng Wang received the B.S. and M.S. degree in aerospace engineeringfrom Tamkang University, Tamsui, Taiwan, in 2003 and 2006, respectively.He is currently a facilities maintenance engineer at Formosa Plastic Associate

Company. His research interests include power electronics, solar powermanagement system, applications of embedded systems, maximum power pointtracking, Li-ion battery power management, and power converter systems.

Jhih-Hua Gong (also known as Chih-Hua Kung) received the B.S. degree inautomation engineering from National Formosa University, Taiwan. He receivedthe M.S. degree in aerospace engineering from Tamkang University, Taiwan in2004.Since graduation, he has been working in design of uninterrupted power

systems, solar-power inverters, and switching-power supplies. He is currentlya senior engineer at Lite-ON Technology Corporation Company, Taiwan. Hisresearch interests include power electronics, solar power management system,applications of embedded systems, and wireless sensor networks.


design of a solar power management system for an experimental uav

Documents

introductionsolar power

maximum available power

maximum power availablefrom

power conversion stages

fromthe solar panel

taiwan jh

mppt tes

ideal energy source