一种基于滑动平均滤波器的同步锁相算法研究

Research on Phase-locked Loop Algorithm Based on Moving Average Filter

摘要:

提出了一种基于滑动平均滤波器的三相软件锁相环，在αβ 轴上添加延时信号消除器滤除直流分量和可能存 在的偶次谐波，改进传统PLL 的控制结构，克服了硬件锁相环存在漂移、失锁、抖动和依赖过零点检测等缺点，避免了 传统软件锁相环难以兼顾稳态检测精度和动态响应速度的不足。采用时域仿真将该方法与传统锁相算法进行对比 分析，结果表明，该算法在三相电压跌落、不平衡、频率跳变以及出现直流分量时均能够准确快速地提取基波正序电 压的幅值、相位和频率。

Abstract:

A novel three － phase software phase － locked loop ( PLL) based on moving average filter is proposed． The delay signal canceller is added on the αβ frame to filter the DC component and the even harmonic components，and to improve the control structure of conventional PLL，which overcomes the deficiencies of hardware PLLs in terms of parameter deviation，out － of － lock，variation and dependency on zero － crossing detection，and also mitigates the shortcomings of the conventional software PLLs due to the tradeoff between the steady － state accuracy and dynamic response． The comparison between the moving average filter － PLL ( MAF － PLL) and the conventional PLL algorithms is presented，which shows that the proposed MAF － PLL provides an accurate estimation of the amplitude，phase and frequency during three － phase voltage sag，voltage unbalance， frequency jump and DC offset．