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This article has been accepted for inclusion in a future issue of this journal. Content is final as presented, with the exception of pagination.

Excitation Synchronous Wind Power GeneratorsWith Maximum Power Tracking Scheme

Tzuen-Lih Chern, Ping-Lung Pan, Yu-Lun Chern, Wei-Ting Chern, Whei-Min Lin, Member, IEEE,Chih-Chiang Cheng, Jyh-Horng Chou, Senior Member, IEEE, and Long-Chen Chen

Abstract—This paper presents a novel excitation synchronouswind power generator (ESWPG) with a maximum power trackingscheme. The excitation synchronous generator and servo motorrotor speed tracks the grid frequency and phase using the proposedcoaxial configuration and phase tracking technologies. The genera-tor output can thus be directly connected to the grid networkwithout an additional power converter. The proposed maximumpower tracking scheme governs the exciter current to achieve stablevoltage, maximum power tracking, and diminishing servo motorpower consumption. The system transient and static responses overa wide range of input wind power are examined using simulatedsoftware. Experimental results from a laboratory prototypeESWPG demonstrate the feasibility of the proposed system.

Index Terms—Excitation synchronous generator, maximumpower tracking, servo motor control, wind power.

I. INTRODUCTION

T HE GLOBAL market demand for electrical powerproduced by renewable energy has steadily increased,

explaining the increasing competitiveness of wind power tech-nology. Wind power generators can be divided into inductionand synchronous types [1]–[8]. The excitation synchronousgenerator driven by hydraulic, steam turbine, or diesel engineshas been extensively adopted in large-scale utility power gener-ation owing to desired features such as high efficiency, reliabili-ty, and controllable output power. A wind power generator ingrid connection applications, except for doubly fed inductiongenerators, achieves these features using variable speed constantfrequency technology. However, most excitation synchronouswind generators cannot be connected directly to the grid, owingto instabilities in wind power dynamics and unpredictable prop-erties that influence the generator synchronous speed. The direct-drive permanentmagnet synchronouswind generator (PMSWG)uses variable speed and power converter technologies to fulfillthe grid connection requirements, which has advantages of being

gearless. Various power transfer technologies are applied forac/dc transformation to obtain a constant frequency ac power[9]–[16]. However, extensive use of power electronic devices inthose systems that will cause unavoidable power losses from therectifier’s conducting resistance and high-frequency powerswitches, which will increase power consumption. Therefore,a converterless method for a high-efficiency excitation synchro-nous wind generator is an important issue, especially for middleand high output voltage wind power generators.

This paper presents a novel converterless wind power gener-ator with a control framework that consists of an excitationsynchronous generator, permanent magnet (PM) synchronousservo motor, signal sensors, and servo control system. The windand servo motor powers are integrated with each other andtransmitted to the excitation synchronous generator via a coaxialconfiguration. When the wind speed varies, the servo motorprovides a compensatory energy to maintain constant generatorspeed. The additional servomotor power is also transformed intoelectricity, and output into the load. This means that the motorpower is not wasted. Using a precise phase tracking functiondesign, the proposed robust integral servo motor control schemereduces the output voltage phase shift in the excitation synchro-nous generator from wind disturbances. According to the servomotor power magnitude and the generator power, the proposedmaximum power tracking scheme controls the excitation fieldcurrent to ensure that the excitation synchronous generator fullyabsorbs the wind power, and converts it into electricity for theloads. Based on physical theorems, a mathematical model for theproposed system is established to evaluate how the controlfunction performs in the designed framework. The detailedstructure and experimental results will be discussed in thefollowing sections.

II. POWER FLOW AND SPEED

For simplicity, assume that all energy transmission elementsbehave ideally, allowing us to ignore the mechanical powerlosses of the wind turbine, the servo motor, and the excitationsynchronous generator. Fig. 1 shows the power flows of theproposed system, where , , and denote the torques and

, , and are the wind turbine, servo motor, and excitationsynchronous generator speeds, respectively. The total excitationsynchronous generator input power is the product of and .The power flow equation can thus be defined as

1949-3029 © 2014 IEEE. Personal use is permitted, but republication/redistribution requires IEEE permission.See http://www.ieee.org/publications_standards/publications/rights/index.html for more information.

Manuscript received August 17, 2013; revised December 29, 2013 and April14, 2014; acceptedMay25, 2014.Thisworkwas supported in part by theNationalScience Council of Taiwan under Grant NSC 102-3113-P-110-005.

T.-L. Chern, P.-L. Pan, Y.-L. Chern, W.-T. Chern, W.-M. Lin, and C.-C.Cheng are with the Department of Electrical Engineering, National Sun Yat-SenUniversity, Kaohsiung, Taiwan (e-mail: [email protected]).

J.-H. Chou is with the Graduate Institute of Electrical Engineering, NationalKaohsiung First University of Science and Technology, Kaohsiung, Taiwan(e-mail: [email protected]).

L.-J. Chen is with the Department of Mechanical and ElectromechanicalEngineering, National Sun Yat-Sen University, Kaohsiung, Taiwan (e-mail:[email protected]).

Color versions of one ormore of the figures in this paper are available online athttp://ieeexplore.ieee.org.

Digital Object Identifier 10.1109/TSTE.2014.2327130

IEEE TRANSACTIONS ON SUSTAINABLE ENERGY 1


Fig. 2 shows the corresponding coaxial configuration. Thewind generator rotor shaft input-end receives rotating torquesfrom the speed increasing gear box. The tail-end of the generatorrotor shaft is coupled with a servo motor. The input energy of theexcitation synchronous generator is the sum of the wind powerand servo motor powers. The speed and rotating direction for thewind turbine output, servo motor, and excitation synchronousgenerator is the same, i.e., the system speeds satisfy

. This arrangement can reduce the power trans-mission losses.

III. CONTROL PRINCIPLES OF PROPOSED WIND POWER

GENERATOR SYSTEM

Fig. 3 depicts the control framework of the proposed system.The control systemdesign conceptsmaintain powerflowbalancebetween the input and the output and, simultaneously, force thegenerator frequency to synchronize with the utility grid. Whenthe system complies with these conditions, the generator outputcan be connected to the utility grid network, subsequentlyreaching the high efficiency and maximum power trackingobjectives. The control signals, including the generator voltage,current, grid phase, motor encoder, and output power, are sensedand transferred to the microprocessor control unit (MCU). Theservo motor controller plays an important role in output powerand grid voltage phase tracking. A situation in which thecontroller detects a power increase from the servo motor impliesdecreasingwind speeds.At thismoment, the system regulates theexciter current to reduce the excitation generator output power. Achain reaction subsequently occurs in which the servo motorpower returns to a balanced level. During the energy balanceperiods, the servo motor consumes only a slight amount of

energy to stabilize the shaft speed. Once (1) is satisfied, boththe maximum power and the constant speed can be obtained bythe designed control scheme.

Fig. 4 schematically depicts the servo motor and maximumpower tracking control (MPTC) loops which are designed tostabilize the speed, frequency, and output power of the excitationsynchronous generator under wind disturbances. The windturbine provides mechanical torque to rotate the generator shaftvia the speed-increasing gear box. As the generator shaft speedsreach the rated speed, the generator magnetic field is excited. TheMPTC then controls the output voltage reaching grid voltage.Moreover, the generator output waveform is designed in phasewith the grid using the servo motor control track grid sinewaveform. Owing to the difficulty in precisely estimating thewind speed, the proposed MPTC scheme measures the motoroutput power as the reference signals to determine the generatoroutput power. The excitation synchronous generator outputfrequency, voltage-phase, and output power are fed back intothe control scheme. The phase/frequency synchronization strat-egy in Fig. 4 compares the grid voltage-phase and frequencywiththe generator’s feedback signals, and produces the positioncommand with pulse-type signals to the servo motor driver.The MPTC also adjusts the excitation field current based onthe wind power and motor power inputs, where denotes theservo motor rotor mechanical rotor angular displacement de-tected by an encoder. Due to the coaxial configuration, detectingthe relative position of the rotor allows us to determine thegenerator voltage phase during the wind power generator system

Fig. 1. Power flow block diagram.

Fig. 2. Proposed coaxial construction configuration.

Fig. 3. Proposed wind power system framework.

Fig. 4. Proposed wind power generator system.

2 IEEE TRANSACTIONS ON SUSTAINABLE ENERGY


operating in the grid connection state. The following sectionsdetail the system sub-blocks configuration.

IV. SERVO MOTOR CONTROLLER DESIGN

The transient and dynamic responses of the servo motorcontroller must satisfy robustness requirements to reduce theinfluence of wind fluctuations to the generator. Thus, the robustintegral structure control (RISC) method is chosen to ensure thevoltage phase and the frequency in phase with the grid. Amonggeneral electricalmotors, the three-phase PMsynchronousmotorhas the advantages of high-efficiency and low-maintenancerequirements, the reason controllable power for the servo controlstructure was chosen in the research [17]–[20]. This study de-signs an analysis model based on the electrical circuit, motortorque, and mechanical theorems. Fig. 5 shows the block dia-gram of the three-phase PM synchronous motor, and Table I liststhe parameters of the PM synchronous motor. According to (1),wind power, generator power, and servo motor power can betransformed into three torque functions and incorporated in thethree-phase PM synchronous motor model.

The electromagnetic torque of the servo motor can beexpressed as [17]

where denotes the number of motor poles, and , , andare the applied stator currents. The mechanical torque can beexpressed as

Additionally, denotes the electrical rotor angular velocity;represents the electrical rotor angular displacement; is the

mechanical rotor angular displacement; is the rotor inertia; andis the damping coefficient.In Fig. 5, denotes the inductance of the stator windings;

represents the amplitude of the flux linkage established by thepermanent magnet as viewed from the stator windings; , ,and are the applied stator voltage of the motor; anddenotes the resistance of each stator winding. Moreover,

is the electrical time constant, and is the mechan

ical time constant. It is clear from the physical characteristicsstated above that the motor electrical time constant is over-whelmingly lower than the mechanical time constant as

. The three-phase PM synchronous motor model canthus be simplified as a first-ordermathematical model, as shownin Fig. 6.

According to Fig. 6, the position control structure includes theRISC and servomotor transfer function. The conventional motorcurrent feedback controller can avoid instantaneous currentstress to the servo driver. This technology has been applied tothe servo motor control to improve the control performance. TheRISC outer loop is designed to achieve a fast and accurate servotracking response under load disturbances and plant parametervariations.

In Fig. 6, denotes the position command. Parametersand are proportional gains and is the integral

gain. The PM synchronous motor state equations aredescribed as

Fig. 5. PM synchronous motor block diagram.

TABLE IPARAMETERS OF PM SYNCHRONOUS MOTOR

Fig. 6. Servo motor position control loops.

CHERN et al.: EXCITATION SYNCHRONOUS WIND POWER GENERATORS 3


where is and is

RISC is a typical state feedback control scheme that combinesan integral controller and the plant series state feedback infor-mation. The RISC function is expressed as (6) and (7), where

and are the plant state variables and is the currentcompensator for the current feedback loops. The pulsewidthmodulation (PWM) circuit mode can be simplified as a constantgain , where denotes the supply voltage;is the triangular waveform peak value; refers to the totaldisturbance which is defined in (5), and is the system controlfunction. For a third RISC system, the control function can beexpressed as follows:

Transfer function of the system is

By designing the system characteristic function to lie on thestable plane, one can obtain

where , , and are the system selected close-loop poles.The characteristic function of (7) can then be rewritten as

The system control gain , , and can be determined by(9) and the pole-zero placement method

V. PHASE TRACKING CONTROL SCHEME

Fig. 7 depicts the proposed phase tracking control scheme.Before the excitation synchronous generator system connects tothe grid ( ), equals to the grid voltage angle. With thecoaxial configuration described in Section II, the servomotor and

generator electrical angle can be obtained using the motorencoder and the grid voltage sensor, respectively. The MCUcompares the phase difference between the two signals, andgradually adjusts the excitation synchronous generator rotorposition to reduce the phase deviation.

Fig. 7 reveals that, while the proposed system contains a phasedeviation , the deviation frequency can be expressed asfollows:

where denotes a constant gain. The new pulse frequencycan be obtained as follows:

The MCU generates pulse trains of frequency command forthe servo motor to drive the servo motor, explaining why thegenerator can lock the generator frequency and phase in the phasecommand.When the generator is connected to the grid ( )

equals the generator current angle. MCU calculates thegenerator electrical angle and current phase angle difference toadjust the generator rotor position to reduce the phase deviation.Consequently, the generator power factor can be controlled andimproved.

VI. MAXIMUM POWER TRACKING CONTROL

In a natural environment, the wind power varies with time. Tostabilize the generator output voltage, current, and output power,the excitation synchronous generator output power has to trackthe input power variation and react immediately by adjusting theexcitation field current. In this paper, a maximum power trackingcontrol scheme is proposed. The proposed MPTC scheme in-cludes two control loops as shown in Fig. 8, which is motorpower control loop, and the generator power control loop. ByMPTC scheme, it can make the motor consumption powerminimize and most of wind power can be transferred to the gridby the generator. The control strategy describes as follows.

As shown in Fig. 8, (1) can be rewritten as

Fig. 7. Phase tracking control scheme.

Fig. 8. MPTC control loops.



where denotes the real wind input power,is the servo motor output power,

is the excitation synchronous generator input power, and isthe calculation motor power.

If an air dynamic occurs in the wind turbine, the servo motorresponses to this change for maintaining generator speed con-stant. The three-phase servo motor power is calculated andcompared to the servo motor command . In thisstate, the servo motor command is set equal tozero. The servo motor deviation signal command passes by themotor power control loop to obtain the signal. As isexpected, in the steady state, the servo motor consumes lesspower. One defines the generator power command as follows:

where denotes a rough wind power value which isestimated by the wind turbine pitch angle and the actual windspeed.

In generator power control loop, the three-phase voltages, and currents of the excitation synchro-

nous generator power output are fed back for comparisonwith the generator power command . This power deviationpassing the PI controller and the excitation gain generates acorresponding excitation field current control signal . Thus theexcitation synchronous generator output power can trackthe generator power command .

VII. THREE-PHASE EXCITATION SYNCHRONOUSGENERATOR MODEL

For a typical three phases, four poles excitation synchronousgenerator, the generator output power is governed by the excita-tion controller, through the slip rings, with the appropriateexcitation current sent to the armature winding. Based on therotating magnetic field affection, the stator windings inducethree-phase alternate voltages which have frequency in synchro-nization with the rotor speed [21], [22]. According to theconductor’s electromagnetism and the mechanical forces on thestator winding and rotor, the generator back electromotive forcevoltage can be defined as

where denotes the back electromotive force voltage of theexcitation synchronous generator stator; represents the con-ductance magnet effective length; is the rotor speed; and isthe magnetic field strength. The magnetic field strength canalso be rewritten as

where denotes the conductance magnet permeability coeffi-cient; represents the number of winding turns; and is therotor current. Combining (14) and (15) yields

where

where denotes the excitation field control power; andrepresent the excitation field equivalent inductance and

resistance, respectively. Considering the distribution of eachmagnetic field phase, in which the back electromotive forcevoltage must be multiplied by a corresponding sinusoidal signal

. The excitation synchronous generator outputs for eachback electromotive force voltage are described as follows:

The generator back torque can be determined as follows:

Fig. 9 shows a block diagram of the three-phase excitationsynchronous generator between the excitation input current andthe generator output according to (15)–(20).

VIII. SIMULATION RESULTS

The generator design functionality is confirmed using a windpower generator framework simulation model with an excitationsynchronous generator and its corresponding sub-systems, usingMATLAB/Simulink and MATLAB/Simpower software. Sub-systems include the wind power input, servo motor phasetracking control, maximum power tracking control, excitationsynchronous generator, and grid connection. Tables I and II listthe parameters of the PM synchronous motor, excitation syn-chronous generator, and Table III shows gains of the PI control-ler, respectively. To output the three-phase voltage signals at60 Hz, the excitation synchronous generator must operate at1800 rpm with 4-pole windings.

Fig. 9. Three-phase excitation synchronous generator.



The voltage phase tracking performance of the system atgenerator output 2 kW is investigated. Fig. 10(a) shows thephase voltage and current waveforms of the excitation synchro-nous generator. Fig. 10(b) shows the grid and generator voltagephase tracking waveforms. The simulation voltage and currentwaveforms in Fig. 10(a) confirm that the proposed system hashigh-quality power and sufficient control stability during grid

connection. The generator output phase voltage is in phase withthe grid in Fig. 10(b). Owing to the excitation synchronousgenerator rotation speed control and excitation control, theoutput power, voltage, and frequency are constant. The windpower generator system can thus connect directly to the grid.

For evaluating the system performance under grid connection,input windwith step changes were applied. In the beginning, 13 sof the simulation, a stable 2-kWwind power input is provided asshown in Fig. 11(a). At the 13th second, a step wind disturbancewith amplitude was suddenly added to observe thepower tracking condition. According to the simulation wave-forms, the excitation synchronous generator output power wasaround 1.9 kW for 0–13 s. Thereafter, the wind power systemtracked the input wind disturbance using the proposedmaximumpower tracking method. Simulation results indicate that, theaverage wind power input error and excitation synchro-nous generator input power was around 0.5% (10W) of thegenerator output power during stable and disturbance periods.The 0.5% power deviation is due to the motor power

TABLE IIIGAINS OF PI CONTROLLER FOR MPTC

TABLE IIPARAMETERS OF EXCITATION SYNCHRONOUS GENERATOR

Fig. 10. Simulation results. (a) Phase voltage and current of the excitationsynchronous generator. (b) Voltage phase tracking.

Fig. 11. Maximum power tracking simulation results. (a) Power tracking curves.(b) Generator input torque. (c) Shaft speed. (d) Shaft acceleration.



consumption. This figure reveals an approximately 90-W powerdifference between the excitation synchronous generator inputpower and output power waveforms. This differ-ence is because the excitation synchronous generator stator coilresistance and inductance influence the system power factor,although those components consume little power. Fig. 11(b)–(d)illustrates the generator input torque, shaft speed, and shaftacceleration which run at the same simulation timewith Fig. 11(a).Fig. 11 indicates that the proposed scheme can make the motorconsumption power minimize and wind power can be fullytransferred to the grid.

IX. EXPERIMENTAL SETUP AND RESULTS

This paper also demonstrates the feasibility of the proposedcontrol system, using an experiment involving a 3-kW synchro-nous excitation wind power generator (ESWPG). A photographof the prototype system with utility grid connection is shown inFig. 12. The proposed system is implemented on a platformconsisting of an MCU Texas Instruments TM320F28M35 Ex-perimenter Kit and Code Composer Studio (CCS). There are twomotors in the experimental system. Motor 1 employs torquecontrol to simulate natural wind power and motor 2 is the servomotor used to complete the phase-locked function. Currenttransducers LEM-CKSR measure the generator and motor cur-rents, and low-frequency transformers sense the generator andgrid voltages. A motor encoder is installed for calculating thegenerator electrical angle and the shaft speed. A firmwareprogram was written to complete the maximum power trackingcontrol and motor phase-locking. Notably, the grid voltage isthree phases of phase to phase. Before thesystem is connected to the grid, a set of three-phase fixedresistance with wye connection is applied as the resistanceloading for the generator.

Fig. 13 shows the transition responses of the experimentalsystem connected to the grid. Ensuring the phase tracking isessential before connecting to the grid. Before grid connection, apreset wind torque accelerates the generator shaft speed up toapproximate 1800 rpm, and the phase tracking control ( )is then started to regulate the generator output voltage waveformin phase with the grid voltage. In this case, three resistances withwye connection as the isolated load were connected to thegenerator. The calculated generator power factor is nearly0.97. After grid connection, to improve the generator power

factor, the phase tracking control is started to regulate thegenerator phase voltage waveform in phase with generator phasecurrent ( ). The measured generator power factor isapproximately 0.94 under grid-connection condition. The mea-sured output power is 2000 W.

The proposed MPTC control system is characterized by thecontroller change generator output power to follow the windpower fluctuation, simultaneously, maintaining output voltage

Fig. 12. Photograph of experimental setup.

Fig. 13. Generator output current and voltage versus grid phase voltage.

Fig. 14. Maximum power tracking experimental results. (a) Wind power stepchanges. (b) Wind power sine wave changes.



waveform in phase with the grid. Consequently, the generatorfully absorbs the wind power and grid connection requirementcan be ensured. To observe the system feasibility, the transientresponses for wind power, generator power, motor power, andgenerator shaft speed were measured as shown in Fig. 14(a) and(b). The system is assumed to have a stable point at a wind powerof 2500 W in the time period beginning in Fig. 14(a) and (b).However, the measured generator power output is only 2000W.The generator output power is 500 W less than the wind power,which is mainly due to the power consumptions of mechanicalfriction and moment of inertia at running speed of 1800 rpm, andthe partial power loss comes from energy conversion efficiencyof the generator. According to Fig. 14(a) and (b), regardless ofwhether the wind is step or sine wave change cases, the proposedMPTC scheme converts the wind energy into electricity. A slightamount of power in the servo motor can maintain the generatorshaft speed constantly and achieve excellent power quality.

X. CONCLUSION

This paper presented an excitation synchronous wind powergenerator with MPTC scheme. In the proposed framework, theservo motor provides controllable power to regulate the rotorspeed and voltage phase under wind disturbance. Using a phasetracking control strategy, the proposed system can achievesmaller voltage phase deviations in the excitation synchronousgenerator. In addition, the maximum output power trackingscheme governs the input and output powers to achieve highperformance. The excitation synchronous generator and controlfunction models were designed from the physical perspective toexamine the presented functions in the proposed framework.Experimental results demonstrate that the proposed wind powergenerator system achieves high performance power generationwith salient power quality.

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Tzuen-LihChernwas born in Kaohsiung, Taiwan, in1958. He received the M.S. and Ph.D. degrees inindustrial control and flight control systems fromthe Institute of Electronics, National Chiao-TungUniversity, Hsinchu, Taiwan, in 1985 and 1992,respectively.

From February 1992 to January 1998, he was anAssociate Professor with the Department of ElectricalEngineering, National Sun Yat-Sen University,Kaohsiung, Taiwan, where he has been a Professorsince February 1998. His research interests include

industrial control, wind power, motor drives, and power electronics.



Ping-Lung Pan was born in Ping-Tung, Taiwan onMarch 28, 1959. He received the B.S. and M.S.degrees in electronic engineering from the I.-SHOUUniversity, Kaohsiung, Taiwan, in 2000 and 2003,respectively. Currently, he is pursuing the Ph.D.degree in control systems and wind power systemdesign at the Department of Electrical Engineering,National Sun Yat-Sen University, Kaohsiung,Taiwan.

Yu-Lun Chern was born in Kaohsiung, Taiwan, in 1988. He received the M.S.degree in motor drive from the Department of Electrical Engineering, NationalSun Yat-Sen University, Kaohsiung, Taiwan, in 2013.

From 2014, he was a TSMC Technology Engineer. His research interestsinclude industrial control, motor drives, and power electronic.

Wei-Ting Chern was born in Taipei, Taiwan, in 1986. He received the M.S.degree in wind power from the Department of Electrical Engineering, NationalSun Yat-Sen University, Kaohsiung, Taiwan, in 2013.

His research interests include wind power and power electronic.

Whei-Min Lin (M’87) was born in 1954. He received the B.S.E.E. degree fromthe National Chao-Tung University, Hsin-Chu, Taiwan, the M.S.E.E. degreefrom the University of Connecticut, Storrs, CT, USA, and the Ph.D.E.E. degreefrom the University of Texas, Arlington, TX, USA, in 1985.

Currently, he is a Professor with the Department of Electrical Engineering,National Sun Yat-Sen University, Kaohsiung, Taiwan. His research interestsinclude geographic information system (GIS), distribution system, supervisorycontrol and data acquisition (SCADA), and automatic control system.

Chih-Chiang Cheng was born in Taipei, Taiwan, onFebruary 27, 1957. He received the B.S. degree inelectrical engineering from Chung Yuan ChristianUniversity, Chung-Li, Taiwan, in 1981, the M.S. andPh.D. degrees in electrical engineering from the Uni-versity of Texas at Arlington, Arlington, TX, USA, in1983 and 1991, respectively, and the Engineer degreein electrical engineering from theUniversity of South-ern California, Los Angeles, CA, USA, in 1985.

Currently, he is a Professorwith theDepartment ofElectrical Engineering, National Sun Yat-SenUniver-

sity,Kaohsiung,Taiwan.His research interests include systemand control theory,with emphasis on design of nonlinear control systems such as variable structurecontrol, backstepping control, adaptive control, and fuzzy control.

Jyh-Horng Chou (SM’04) received the B.S. andM.S. degrees in engineering science from NationalCheng-KungUniversity, Tainan, Taiwan, in 1981 and1983, respectively, and the Ph.D. degree in mecha-tronic engineering from National Sun Yat-SenUniversity, Kaohsiung, Taiwan, in 1988.

Currently, he is the Chair Professor with theDepartment of Electrical Engineering, NationalKaohsiung University of Applied Sciences,Kaohsiung, Taiwan, as well as the DistinguishedProfessor with the Institute of Electrical Engineering,

National Kaohsiung First University of Science and Technology, Kaohsiung,Taiwan. His research and teaching interests include intelligent systems andcontrol, computational intelligence and methods, automation technology, robustcontrol, and quality engineering.

Long-Jeng Chen received the Ph.D. degree from theDepartment ofMechanical Engineering,University ofIowa, Iowa City, IA, USA, in 1990.

He is an Associate Professor with the Departmentof Mechanical and Electro-Mechanical Engineering,National Sun Yat-Sen University, Kaohsiung,Taiwan. His research interests include power genera-tion by water or wind turbine and developments ofPEM fuel cells.


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