A ZERO-STEADY-ERROR CONTROL SCHEME OF THREE-PHASE THREE-WIRE ACTIVE POWER FILTER

Three-phase shunt active power filter (APF) is often used to compensate the harmonics and reactive current derived from nonlinear loads. But many non-ideal factors, such as the limited bandwidth of current control loop and the time lag of signal acquisition and reference current generation etc, will deteriorate the compensation effect. The traditional Proportion-integral (PI) controller cannot be used simply to control the output current without any steady error due to its limited current tracking capability A novel current control architecture in the synchronous rotating frame with ordinary PI and appointed harmonic current control out-loops is proposed in the paper. The appointed order harmonic out-loops are used to improve the precision of APF's appointed order harmonic currents compensation, while the ordinary PI controller is used to ensure the dynamic response performance of APF. The experimental results verify that current control architecture is available and efficient.