Study on the Improved Harmonic Detection Algorithm Based on FBD Theory

Harmonic detection is an important issue for the performance of active power filter (APF), which should provide harmonic current or reactive current accurately and rapidly. At the same time, the detection algorithm is desired to be simple. An improved FBD method combining the generalized inregrator (GI) is proposed. Generalized integrator is used to provide the phase information of the positive sequence fundamental voltage extracted from the grid voltage, which can avoid the effect of voltage distortion to FBD harmonic detection method. The simulation and experimental results prove the validity of the proposed harmonic detection algorithm.