双馈风力发电低电压穿越撬棒阻值模糊优化

Fuzzy Optimization of Crowbar Resistances for Low-voltage Ride Through of Doubly-fed Induction Generators

撬棒(crowbar)保护是双馈风力发电机组实现低电压穿越的主要控制方法之一。针对传统撬棒阻值设计与定转子电流约束条件边界取值相关,进而影响系统安全性这一问题,采用模糊优化理论,分析电网发生三相短路故障时转子电流峰值估算式以及撬棒阻值约束式;根据模糊优化机制及上述阻值约束关系,建立撬棒阻值模糊集隶属函数及模糊目标函数。针对1.5 MW双馈风电机组撬棒阻值进行模糊优化设计,并对设计结果在Matlab/Simulink平台上进行了仿真验证。仿真结果表明,撬棒阻值优化可以显著减小双馈机组低电压穿越时的定转子电流、直流母线电压及电磁转矩振荡,有效提高风电系统的安全可靠性。

The crowbar control is one of the main methods for low voltage ride through（LVRT） of doubly-fed induction generators（DFIGs）.The traditional crowbar resistance design is associated with the constraint boundary valve of the stator and rotor current,and thus the system security is affected.From this point of view,the fuzzy optimization theory was applied to derive the estimation expression of the peak rotor current of DFIG and the constraints of the crowbar resistance in the case of three-phase short-circuit faults in power grids.According to the fuzzy optimization mechanism and above constraints,the fuzzy sets membership function and fuzzy objective function about the crowbar resistance were established.The crowbar resistance of a 1.5 MW DFIG was designed by applying above fuzzy optimization method,and a series of simulations were conducted in the Matlab/Simulink platform.The simulation results show that the current of the rotor,oscillation of the bus voltage and the electromagnetic torque oscilation can be reduced by the crowbar resistance optimization,meanwhile,the operation reliability of DFIG sets can be effectively improved.