不平衡电网电压下双馈风力发电系统的比例-积分-谐振并网控制

Proportional-Integral-Resonant Grid-Connection Control for Doubly-Fed Wind Power Generation System Under Unbalanced Grid Voltage

提出双馈发电机(doubly-fed induction generator,DFIG)的比例-积分-谐振(proportional integral resonant,PIR)并网控制方法,以实现电网电压不平衡工况下DFIG风力发电系统的并网控制。并网控制器由同步旋转坐标系中的比例-积分控制器和谐振控制器组成,比例积分控制器控制定子d-q轴电压的直流分量,谐振控制器控制定子d-q轴电压的交流分量,使其分别实现对电网d-q轴电压直流、交流分量的精确跟踪。该比例-积分-谐振并网控制策略具有无需采用正负序分离算法,无需设计负序控制器等优点。仿真结果表明,该并网控制策略在电网电压平衡和不平衡条件下,均可控制DFIG定子电压实现对电网电压的精确跟踪。

A grid-connection approach for wind power generation system composed of doubly-fed induction generators （DFIG） by proportional integral resonant （PIR） controller under unbalanced grid voltage is proposed. The PIR controller is consisted of PI controller and resonant controller in synchronous reference frame, the PI controller controls DC voltage components in d-q axes of stator to follow DC voltage components in d-q axes of power grid, and the resonant controller controls AC voltage components in d-q axes of stator to follow AC voltage components in d-q axes of power grid, thus accurate tracking of DC and AC voltage components in d-q axes of stator to those in d-q axes of power grid can be implemented. The proposed PIR grid-connection control strategy possesses such advantages as needing not to decompose positive-sequence components and negative- sequence components as well as needing not design negative-sequence controller. Simulation results show that under both conditions of balanced and unbalanced grid voltage the accurate tracking of stator voltage of DFIG to grid voltage can be implemented by the proposed grid-connection control strategy.