电网畸变条件下有源电力滤波器同步锁相研究

Synchronous Reference Frame Phase-locked Loop for Active Power Filtering under Distorted Grid Conditions

电网畸变条件下,如频率脉动、电压谐波过大和存在直流分量时,会导致有源电力滤波器的锁相精度下降,为此提出了一种由滑动平均滤波器(MAF)和同步锁相环(SRF-PLL)组成的有源电力滤波器同步锁相方法,该方法在同步旋转坐标系中利用滑动平均滤波器(MAF)从畸变电网信号中提取精确的基波正序分量,保证了SRF-PLL无静差、高精度的跟踪电网的相位,从而使有源电力滤波器在电网畸变条件下具有很好的适应性,仿真和试验结果验证了该锁相方法的有效性和优越性。

The operation of active power filters under distorted grid conditions, such as grid-frequency fluctuation and voltage-harmonics and DC component, can lead to significant degradation in harmonic compensation performance. For that reason, this paper combines the moving average filter with the synchronous rotating frame phase-locked loop （SRF- PLL） to improve the performances of conventional SRF-PLL. It utilizes the moving average filter （MAF） to accurately ex- tract the fundamental positive-sequence component of grid voltage under the synchronous reference frame. The SRF-PLL achieves the accurate synchronization with zero steady state errors, so as to ensure that the active power filter has good adaptability under the condition of grid distortion. The simulation and experimental results verify the effectiveness of the superior performance.