基于转子串电阻的双馈风电低电压穿越暂态功率优化控制

LOW VOLTAGE RIDE-THROUGH TRANSIENT POWER OPTIMIAZATION CONTROL STRATEGY OF DOUBLY-FED INDUCTION GENERATORS BASED ON ROTOR SERIES RESISTOR

针对双馈风力发电机转子串电阻低电压穿越控制,提出一种动态功率优化控制策略,根据电网电压跌落深度的前馈控制,实时改变双馈电机有功功率给定值,进而快速有效地控制双馈电机的功率输出,实现转子变流器两侧的功率平衡;利用转子串电阻低电压穿越期间双馈电机的可控性,在确保系统稳定和转子变流器电流不越限的情况下,为电网提供尽可能多的无功支撑,促使电网故障电压快速恢复。基于10 kW的双馈风力发电模拟平台实验结果表明,该算法在无需添加额外硬件设备的同时,可基本实现系统的安全、稳定、零电压穿越运行,且可降低系统的成本,具有一定实用性。

To improve the low voltage ride through(LVRT)performance in a doubly-fed induction generator(DFIG)based on rotor series resistor,a dynamic power optimization control strategy is proposed in this paper.This strategy is according to the feed-forward control of the grid voltage dips depth to change the given value of the active power of the DFIG in real time,and control the active power output of the DFIG quickly and effectively,which realizes the power balance between input and output of the DFIG.In the proposed method,the controllability of the DFIG during the LVRT based on rotor series resistor is exploited,on the premise of ensuring the stability of the system and the rotor current of the converter within the acceptable limits,this strategy provides the reactive power support as much as possible and promotes the fast recovery of fault voltage on the power-grid.The experimental results based on a 10 kW wind power generation simulation platform indicate that the proposed algorithm does not require any extra hardware equipment,and it basically realizes the safety,stability and zero-voltage ride-through operations of the system.Besides,the cost of the system is reduced.Therefore,it has very good practicability.