针对无刷双馈风力发电系统,稳态时,采用基于空间矢量调制(Space Vector Modulation,SVM)的直接功率控制(Direct Power Control,DPC)技术.在电网电压对称跌落条件下,理论分析功率绕组磁链与控制绕组电压的关系,对于故障期间控制绕组会产生较大的过电流,严重时可能损害变流器功率器件的问题,在原有的控制方案中引入前馈控制.通过将可观测的功率绕组电流进行微分运算后得到反映控制绕组反电势的直接干扰量,将其经前馈控制器引入到控制电压的参考值端,形成一种基于前馈控制的SVM-DPC复合控制.仿真结果表明,基于功率绕组电流微分前馈控制的复合控制策略可以在一定程度上抑制控制绕组过电流,能为无刷双馈风力发电机实现低电压穿越提供参考.
Research on Low Voltage Ride Through Control Strategy of Brushless Doubly-fed Wind Turbine
For the brushless doubly-fed wind power generation system,the direct power control(DPC)technology based on space vector modulation(SVM)is used in steady state.Under the condition of symmetrical voltage drop in the grid,the relationship between the power winding flux and the control winding voltage is theoretically analyzed.During faults,the control winding may generate large overcurrent,which can damage the inverter power devices.To address this issue,feedforward control is introduced into the original control scheme.By differentiating the observable power winding current,a direct disturbance reflecting the control winding back-EMF is obtained.This is introduced into the reference value end of the control voltage through a feedforward controller,forming a composite control strategy based on feedforward control SVM-DPC.Simulation results show that the composite control strategy based on power winding current differential feedforward control can suppress the overcurrent of the control winding to some extent and provide a reference for low voltage ride through of brushless doubly-fed wind turbines.
brushless doubly-fed reluctance generatorlow voltage ride throughspace vector modulationdirect power controlfeed forward control
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