新型永磁风电系统的低电压穿越性能研究

LVRT ability of PMSG wind power system

提出一种基于固态变压器的新型永磁风电并网系统,采用超级电容构建Crowbar电路实现低电压穿越功能,并网逆变器采用正负序电压定向控制策略。研究了超级电容工程模型的充放电特性,根据低电压穿越要求,计算出Crowbar电路中超级电容的容量,通过直流母线功率平衡要求在Crowbar电路控制中采用电压差检测的方法,控制超级电容的充放电。仿真结果表明,该系统在各种电压跌落情况下均能维持直流母线电压稳定,并网电流保持正弦。

A grid-connected PMSG（Permanent Magnet Synchronous Generator） wind power system based on solid state transformer is proposed,which applies super capacitor to built Crowbar circuit for LVRT（Low Voltage Ride Through） and adopts the positive/negative sequence voltage oriented control strategy for grid- connected inverter. The charge/discharge characteristics of super capacitor engineering model are researched and the capacity of super capacitor in Crowbar circuit is calculated according to the requirement of LVRT. The voltage difference detection is used in the control of Crowbar circuit to control the charge/discharge of super capacitor according to the requirement of power balance of DC bus. Simulative results show that,the proposed system maintains the DC voltage stable and the grid-connected current sinusoidal under various voltage drop situations.