用于并网逆变器的频率自适应复合重复控制

Frequency Adaptive Compound Repetitive Control for Grid-connected Inverters

针对电网频率波动时重复控制(repeat control,RC)难以准确跟踪谐波分量和周期性干扰的问题,提出一种频率自适应复合重复控制策略(frequency adaptive PRC,FAPRC)。采用基于幂级数的滤波器实现分数延时。电网频率发生波动时,只需要输入频率比值的小数部分就能在基频和各次谐波频率处产生高增益,对实际电网频率进行准确跟踪,从而增强了系统在频率波动时的无静差跟踪能力和谐波抑制能力,实现频率自适应。在电网频率变化情况下对该控制策略进行仿真分析,与复合重复控制策略相比,所提策略更具优越性。

For the fact that repetitive control(RC)cannot effectively suppress current harmonics when the grid frequency fluctuates,an improved frequency adaptive repetitive control(FAPRC)strategy,which uses a power-based filter to achieve fractional dclay is proposed.Since the filter is only related to its own order,when the grid frequency fluctuates,only adjusting the fractional part of the input frequency ratio can produce high gain at the fundamental frequency and cach harmonic frequency to accurate tracking of the actual grid frequency,thus enhancing the system's ability to track without static difference and harmonic suppression when the frequency fluctuates,and realizing frequency adaptive.This control strategy is simulated and analyzed in the case of power grid frequency fluctuations,and compared with repetitive control to verify the effectiveness of the proposed strategy.