弱电网条件下的有源电力滤波器无锁相环控制

Active Power Filter Control Strategy Without Phase-locked Loop Under Weak Grid Condition

分布式电源比重较高的弱电网系统电网阻抗较大,有源电力滤波器(APF)接入系统的公共连接点(PCC)电压通常会发生畸变、不平衡以及频偏。APF的传统控制策略中,锁相环在电压畸变、不平衡时存在检测误差,而改进的锁相环通常算法复杂且会引入额外的延时。基于虚拟坐标系推导出一种改进的控制策略。该控制策略不需要锁相环,且算法简单。仿真和实验结果显示,采用改进控制策略的APF在弱电网的PCC电压发生畸变、不平衡及频偏时,可以准确快速地进行补偿。

The impedance is large and the point of common coupling voltage usually occurs distortion,unbalance and offset for weak grid with high proportion of distributed energy resources connected with active power filter(APF).For APF conventional control strategy,the phase-locked loop(PLL)has error under voltage distortion and imbalance condition,and improved PLL is usually complexity and introduces additional delay.An improved control strategy was carried out based on virtual coordinate.The control algorithm was simple and no need PLL.The simulation and experiment results show the improved control strategy ensures APF owns good accuracy and dynamic performance under weak grid PCC voltage distortion,unbalance and offset condition.