风力发电系统中PWM整流器脉宽调制方法的研究

摘要

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.%近年来,离网型风力发电(isolated WECS)引起了人们的广泛关注,为了获得可靠平稳的负载电压,风力发电机侧整流器的控制至关重要.针对PWM整流器的动态响应问题,首先分析了当前主流的三相电压型PWM整流器(VSR)的拓扑结构、数学模型及控制策略,然后通过公式推导引出了基于电网电压定向的矢量控制策略,最终在基于Matlab Simulink平台搭建了三相VSR仿真模型,分别用正弦脉宽调制(SPWM)与空间矢量脉宽调制(SVPWM)方法进行了仿真研究.研究结果表明,基于电网电压定向的矢量控制能够有效控制PWM整流器,获得稳定的直流母线电压,同时空间矢量脉宽调制方法能够有效改善VSR动态性能,为离网型风力发电系统的研究提供了有力参考.