Four H-bridge based shunt active power filter for three-phase four wire system

This paper proposes a shunt active power filter (SAPF) composed of four H-bridge converters. Each of them is connected by means of isolation transformers. Compared to conventional topologies, the proposed converter permits reducing: dc-link voltage rating, grid current harmonic distortion and/or switching frequency (switching losses). A suitable control strategy to adjust the filter currents as well as dc-link voltage are presented. Two PWM strategies are designed to command the converter according to the reference voltage provided by the controllers. Simulation and experimental results are presented in order to validate theoretical approaches.