有源电力滤波器谐波检测的新型SRF-PLL设计研究

Research on the Design of SRF-PLL for Active Power Filter Harmonic Detection

针对有源电力滤波器中基于同步坐标系的锁相环(synchronous reference frame PLL,SRF-PLL)在三相电网电压不平衡且有畸变时,负序基频分量和高频谐波电流对SRF-PLL的影响。文章采用在基于同步坐标系的锁相环中加入自适应陷波器(adaptive notch filter,ANF)和自适应滤波器(adaptive filter)的技术。利用自适应陷波器的两个相互正交的输出量抵消同频负序分量导致的2倍工频波动,并采用自适应滤波器的最小均方算法(Least Mean Square,LMS)滤除高频谐波分量,从而准确的提取基波电压的幅值与相位。文章以单独加入自适应滤波器或自适应陷波器作比较,通过仿真分析验证文中方法能更加准确的提取电网电压频率,正余弦函数曲线更加平滑,具有良好的动态性能和稳定性。

The effect of negative sequence fundamental frequency component and high frequency harmonic current on SRF-PLL in synchronous reference frame PLL in active power filter is studied.In this paper,adaptive notch filter and adaptive filter are added to the phase-locked loop based on the synchronous coordinate system.Two orthogonal outputs of the adaptive trap are used to offset the power frequency fluctuation caused by the negative sequence components of the same frequency,and the minimum Mean Square algorithm of the adaptive filter is used to filter out the high-frequency harmonic components,so as to extract the amplitude and phase of the fundamental wave voltage accurately.In this paper,an adaptive filter or an adaptive notch is added to make a comparison.Through simulation analysis,it is verified that the proposed method can extract the power grid voltage frequency more accurately,the sines and cosines function curve is smoother,and has good dynamic performance and stability.