分析了双馈感应电机(doubly-fed induction generator,DFIG)在电网故障工况下的动态特性,推导了定子磁链和转子感应电动势表达式,研究了一种反电流跟踪控制策略。基于定、转子电流变化关系,设计电流跟踪系数,控制转子电流反向追踪定子电流的变化,有效抑制转子过流,实现DFIG低电压穿越(low voltage ride through,LVRT),确保发电系统平稳持续运行。控制手段简易,电流跟踪系数可控,能有效缓和转矩振荡。通过Matlab/Simulink平台进行仿真研究,结果表明了该方法的正确性和有效性。
英文摘要:
The dynamic characteristic of the doubly fed induction generator(DFIG) under failure operating mode of grid was analyzed, the expressions of stator flux and rotor side induced electromotive force were inferred, a reverse current tracking control strategy was studied. To suppress rotor over-currents effectively, achieve the low voltage ride through(LVRT) of DFIG, and make sure the steady and continuous running of power generation system, the current tracking coefficient was designed based on the relationships between stator current and rotor current, rotor current was controlled to track the change of stator current in opposite direction with the coefficient. The means of control is simple and convenient, current tracking coefficient is controllable and the method can moderate the torque oscillation efficiently. Simulation study was carried out by Matlab/Simulink, and the results showed the validity of the proposed control strategy.