The Research on Composite Control Strategy of Active Power Filter

In order to improve the performances of the active power filter used in a three-phase three-wire system, this paper proposes an integrated control system including the hysteresis controller and proportional resonance controller. The current loop controller and proportional integral voltage loop controller construct the proportional resonance controller. At first, the integrated control system measures the load harmonic current by the harmonic current detection algorithm. Then the proportional resonance controller and hysteresis controller generate the compensation current which has the same amplitude and reverse phase as the harmonic measurements. Finally, the compensation current is injected into the power grid to cancel the harmonic current. The simulation results show that the integrated control system tracks and compensates the harmonic current quickly, and it also mitigates the power system current distortion factor effectively.