Design of Adaptive Increment Controlled Hybrid-Type Active Power Filter
HAPF (HAPF) is composed of an active power filter (APF) and a passive power filter (PPF), for integrated harmonic compensation of unbalanced or nonlinear loads and compensation of reactive power. The PPF tunes at special harmonics and compensates reactive power to improve the power factor. The APF is composed of two full controlled three-phase PWM inverters. It traces harmonic current on system line, and works as a controlled voltage source, injecting current into system to eliminating harmonic current generated by nonlinear loads. In structure design, the PPF supplies fundamental series resonance brunch for APF to avoid enduring fundamental voltage. It lowers the rated capacity of APF and reduces the volume of APF. The adaptive increment control method is employed, which is simple and fast responding. It enables the control of APF independent of the parameters of PPF. It makes the filter flexible to harmonics, and overcome the effect of input current of APF. Simulation and experiment have been carried out. The result shows that the design achieves expected goals. The harmonic in system is reduced below expect level, and the filter is fast response and adaptive to the harmonic current.