A novel fundamental wave detection method and its application in the active power filter

Based on the least-squares principle, a fundamental detection algorithm is proposed. The presented algorithm is capable of not only extracting the fundamental component from the voltage or current signal containing harmonics, but also tracking the fundamental frequency and phase, which can supply the synchronizing reference signal for the system. The theoretical analysis and the practical implementation of this method have been discussed in detail. Its high filtering performance and fast dynamic response have been verified by the simulation and experiment. In this paper, a laboratory prototype of the current-source active filter is built, which employs the proposed technique to generate the current reference signal for harmonic compensation, and the voltage synchronizing reference signal for DC side active power control.