Eight‐switch CHB‐based three‐level three‐phase shunt active power filter

Abstract

This study presents a reduced switch three-phase three-level H-Bridge-based shunt active power filter (SAPF) for the mitigation of current harmonics, the reduction of current unbalance and the injection of reactive power. This recommended SAPF is developed by using two H-bridge and two DC-link capacitors. Compared to the conventional three-level H Bridge-based SAPF, the eight-switch cascaded H bridge (ES-CHB)-based topology saves four semiconductor switches and one DC-link capacitor. The ES-CHB-based SAPF saves the power electronic components and reduces voltage stress across each switch by introducing a small AC capacitor in series with coupling inductor in each phase. This LC circuit also reduces the harmonic stress of SAPF by tuning at the sixth order of current harmonics. The only drawback of the suggested SAPF is the DC link voltage unbalances. To address this problem, a modified feedback control strategy is proposed in this study. The modified controller regulates the DC link voltage at the desired voltage and mitigates the DC link voltage unbalances, by using reactive power flow control and active power flow control, respectively. The performance of the suggested eight-switch three-level CHB-based SAPF is evaluated through MATLAB simulation and experimentally verified through the hardware implementation.