A Novel Active Power Filter based on Injection of α-β Current Components to Power System

The proliferation of a variety of nonlinear loads and resonance in utility power system results in a large amount of harmonics injection to power system. Active power filter (APF) based on power electronic technology is currently considered as the most competitive equipment for mitigation of power harmonics. Usually, the configuration of APF is referred to one based on voltage source inverter due to easy implementation. Researches on APF mainly focus on two fields: topologies and control strategies. A new topology of APF proposed in this paper is based on the theory of α - β coordinate transformation. This topology accomplishes decoupling of three-phase harmonic currents directly in power converters. Thus, harmonic currents can be injected into power system by directly using two single-phase inverters for three-phase three-line system. By this way, interference by three-phase inverter during harmonic compensation is avoided, and large power APF for harmonic compensation can be achieved easily. The simulation results verify the viability and validity of the novel APF.