Shunt Active Power Filter Using Asymmetric Cascaded Multilevel Converter

Power quality conditioning is a critical issue in the current scenario due to the continuous increase in the proliferation of non-linear loads. This work presents an asymmetric cascaded H-bridge multilevel inverter for active power filter applications. In this topology, three H-bridges per phase are cascaded in series, with voltage sources in the ratio of 16:4:1. This voltage asymmetry results in a high-resolution output voltage, making it a promising converter for these applications. This topology has the potential to compensate low power factor and high harmonic load currents which makes it suitable for medium voltage and high-power applications. The reference current for compensation is calculated using the instantaneous p-q theory. The high-resolution output results in excellent performance in tracking the compensating current reference. A three-phase uncontrolled rectifier has been utilized as a non-linear load to introduce distortion in the grid current. Simulation results obtained from the MATLAB/Simulink environment demonstrate that the proposed topology has significant potential for active power filtering in medium-voltage and high-power applications.