一种改进无锁相环FBD谐波和无功电流检测方法

谐波和无功电流的准确检测,是影响有源电力滤波器补偿性能的关键技术之一。针对传统FBD法在检测谐波和无功电流上的不足,提出一种改进无锁相环FBD检测方法。该方法利用基波正序电压提取环节代替锁相环电路,对两路线电压进行处理,得到与基波正序电压同频同相的三相参考电压信号,进而求取补偿指令电流。检测结果不受电网电压不对称和畸变的影响,消除了锁相环引起的误差。仿真分析和实验结果验证了该方法的正确性和可行性。

An Improved FBD Method without PLL on Harmonic and Reactive Currents Detection

Detecting harmonic and reactive currents accurately is one of the key technologies which influence the compensation performance of active power filter. Aiming at the shortcomings of traditional FBD method in detecting harmonic and reactive currents, an improved FBD detection method without phase-locked loop is proposed in this paper. This method uses the fundamental positive sequence voltage extracting segment instead of phase-locked loop, to get three-phase reference voltage signals having the same frequency and phase with the fundamental positive sequence voltage, by processing two line voltages, and then to obtain the compensation command currents. The detection result is not affected by the asymmetry and distortion of the grid voltage, and eliminates the error from phase-locked loop. Simulation analysis and experimental results verify the correctness and feasibility of this method.