考虑转子电压电流耦合全补偿的双馈感应发电机改进PI-R电流控制策略

Improved PI-R current control strategy with complete compensation for coupled harmonic voltage and current of DFIG rotor

对电网谐波环境下基于PI-R电流控制器的双馈感应发电机(DFIG)控制策略进行了改进。建立了计及电网谐波的DFIG动态模型,分析了电网谐波环境下实现DFIG控制的常用方法。针对常用控制策略中未考虑DFIG转子谐波电压和谐波电流之间耦合的问题,提出了相应的改进方法,即通过对转子谐波电压和谐波电流间的交叉耦合进行补偿,实现了快速动态解耦控制,改善了控制性能。给出了考虑转子谐波电压电流耦合补偿的PI-R电流控制器设计方法。在PSCAD/EMTDC上进行了仿真,验证了改进方案的正确性和有效性。仿真证明,所提出的改进策略在保留PI-R控制器对交、直流量实现无静差控制特性及其良好的频率选择性的同时,更加有效地抑制了电网谐波对DFIG转子电流畸变和功率脉动的影响,进一步提升了电能质量。

The DFIG（Doubly-Fed Induction Generator） control strategy based on PI-R current controller in the harmonic environment of power grid is improved. A dynamic DFIG model considering grid harmonics is established and the commonly-used DFIG control strategies in the harmonic environment of power grid are analyzed. Since the commonly-used DFIG control strategies do not consider the coupled harmonic voltage and current of DFIG rotor,an improved control strategy is put forward,which compensates the cross coupling between them to realize the decoupled fast dynamic control and improve the control performance. A method for designing the PI-R current controller with rotor harmonic voltage and current coupling compensation is presented. PSCAD/EMTDC simulations are carried out to verify the correctness and effectiveness of the improved strategy and the simulative results prove that,the influence of grid harmonics on the current distortion and power fluctuation of DFIG rotor is effectively suppressed and the power quality is further enhanced,while the good control performances of PI-R controller are kept,such as the AC/DC variable control without static error and the excellent frequency selectivity.