Abstract：Active power filters (APF) are used to improve the electrical power quality when the power electronic converters have nonlinear loads. The ip-iq harmonic current detection algorithm is commonly used to attain command current in APF, but the detection results often deviate from the real harmonic current due to the phase-lock of PLL is not accuracy enough. And the existing harmonic current detection algorithms without using PLL have difficulty to separate fundamental active current and reactive current. A non-PLL harmonic current detection algorithm is proposed in this paper to solve such problems mentioned above. The proposed detection algorithm can separate the fundamental active current, reactive current and harmonic current, and it has better real-time features compared with traditional method, the affection on detection accuracy from frequency difference and voltage distortion is also smaller. The proposed detection algorithm need to separate low frequency component correctly, this paper makes analysis and comparison on several low frequency separation methods, and the validity of proposed detection algorithm is verified by simulation results.
2015, Vol. 16 
