一种频率自适应滑动平均滤波器的电网同步方法

针对电网电压畸变条件下电力电子变流器的同步锁相问题,提出一种基于频率自适应滑动平均滤波原理的同步锁相(MA-PLL)方法.该方法在传统的同步锁相环基础上,利用滑动平均滤波器在零点频率处的高衰减性能,消除畸变电网条件下电压谐波及不平衡分量对同步锁相的精度影响；采用频率自适应和幅值归一化方法,提高锁相环在电网电压频率变化与幅值波动时的跟踪性能；采用小信号分析法,对锁相环系数进行设计和选取,提高锁相环的动态响应.实验结果表明:在电网电压畸变、不平衡以及频率变化情况下,提出的方法均能准确快速地获得电网的相位和频率信息.

A grid synchronization method using frequency adaptive moving average filter

In order to deal with the grid synchronization problem of power electronic converter under distorted grid voltage conditions,a synchronization method based on frequency adaptive moving average filter phase locked loop (MA-PLL) was proposed. A moving average filter is inserted in the conventional synchronous rotating frame PLL in order to eliminate the influence of unbalance and harmonic distortion voltage components in adverse grid conditions. In addition, frequency-adaptive algorithm and magnitude normalized method are used to improve the performance of MA-PLL under the frequency variation and magnitude voltage fluctuation. The PLL coefficients are optimized by the small-signal model analysis method, which improveds the dynamic performance of MA-PLL. The experimental results show that the proposed MA-PLL can accurately and rapidly obtain grid phase and frequency information under adverse grid conditions (e.g., grid voltage distortion, voltage imbalance and frequency variation)．