PWM modulation methods of PWM rectifiers in WECS

PENG Cheng， PAN Zai-ping
（College of Electrical Engineering， Zhejiang University， Hangzhou 310027， China）

Abstract： In recent years，isolated wind energy conversion system（WECS） has aroused widespread concern，to obtain reliable and steady output voltage，the control characteristics of motor-side rectifier was evidently the key point. Aiming at dynamic response of PWM rectifier，firstly，the topology，mathematic model and control strategy of the most popular three phase voltage PWM rectifier were separately analyzed；Then，the vector control strategy based on grid voltage orientation was proposed through formula derivation，finally three phase VSR emulation model was established with Matlab Simulink using different PWM modulation methods（SPWM and SVPWM）. The results indicate that the control strategy proposed above was effectively demonstrated in achieving steady DC-bus voltage；meanwhile，SVPWM strategy was well proved in improving the dynamic response of VSR. The simulation results provide reference to the control of isolated WECS.
Key words： isolated wind energy conversion system（WECS）； voltage source rectifier（VSR）； vector control； pulse width modulation（PWM）