摘要
谐波检测是有源电力滤波器(Active Power Filter, APF)的重要控制策略之一,当电网电压不平衡或畸变时,采用传统谐波检测方法会导致APF的谐波检测产生误差,最终的补偿效果变差。本文基于瞬时无功功率理论,推导了完美谐波消除法(Perfect Harmonic Cancellation, PHC)的补偿电流计算公式。PHC法检测谐波时提取了电网电压的正序基波分量,排除电网不平衡和畸变的影响,减小了谐波检测的误差。最后,本文对PHC法进行仿真验证,分别仿真了电网电压正常和电网电压畸变或畸变的情况,并与传统的p-q法和d-q法的补偿效果进行对比,证明了在电网电压不平衡或畸变的情况下,采用PHC法的APF具有更理想的补偿效果,验证了PHC法的正确性和优越性。
Harmonic detection is one of the most important control strategies in active power filter (APF). When the grid voltage is under distorted or unbalanced circumstance, the harmonic detection of APF causes error using the conventional harmonic detection methods, and the compensation effect is unsatisfactory. The compensating current equation of the perfect harmonic cancellation (PHC) is derived based on Instantaneous Reactive Power Theory in the paper. The PHC method uses positive sequence components of the grid voltage without the effect of distortion and unbalance while detecting harmonic. It makes for error reduction. Finally, the PHC method is simulated in the paper when the grid voltage is under normal circumstance or distorted and unbalanced circumstance. The simulation results verify that the APF using the PHC method has more satisfied compensation effect when the grid voltage is under distorted and unbalanced circumstance, and it proves that the PHC method is correct and superior.
