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并联有源电力滤波器(APF)通常从负载侧检测谐波电流作为APF的指令电流,由于谐波电流变化率较大,且APF本身也会产生附加谐波,使得APF补偿精度不高。针对APF存在的问题,本文提出一种基于瞬时无功理论的三相四线制并联APF综合补偿算法,采用特定次谐波检测算法从网侧检测计算谐波电流及零序电流,从负载侧检测计算负载无功电流及负序基波电流,三相桥臂与零序桥臂解耦后采用无差拍控制实现对谐波及无功的综合补偿。补偿后电网谐波电流含量低,电流与电压相位差很小,中线电流接近零,动态响应快且不论负载对称或不对称都适用,实验结果证明了本文控制策略的有效性。
Parallel Active Power Filter (APF) usually detects the harmonic current from the load side as the command current of the APF. Due to the large harmonic current change rate and the additional harmonics generated by the APF itself, APF compensation accuracy is not high. Aiming at the existing problems of APF, this paper proposes an APF synthesis compensation algorithm based on instantaneous reactive power theory. The harmonics current and zero-sequence current are calculated from the network side using a specific subharmonic detection algorithm. From the load side Detection and calculation of load reactive current and negative sequence fundamental current, three-phase bridge arm and zero-sequence bridge armless control using beatless to achieve a comprehensive compensation of harmonic and reactive power. After the compensation, the content of harmonic current in power system is low, the phase difference between current and voltage is small, the neutral current is close to zero, and the dynamic response is fast and applicable irrespective of load symmetry or asymmetry. Experimental results show the effectiveness of the proposed control strategy.