Influence of Switching Strategy on Capacitor Current in a Two Level Converter

Abstract

DC-link capacitors are widely used in power electronic systems to supply instantaneous power imbalances and to filter harmonics arising from switching and voltage imbalances. However, these harmonics will shorten the life of the capacitors, making them a bottleneck for the system's reliability. This paper presents the impact of switching strategies and the converter configuration on the DC-link capacitor harmonics. It also presents the design and simulation of the Active Front End Converter (AFEC). Total Harmonic Distortion of capacitor current with  AFEC is compared to that of a normal rectifier. The AFE converter achieves near-unity power factor, minimal harmonic distortion, enabling efficient bidirectional power flow, particularly beneficial for electric vehicle charging infrastructure and renewable energy integration into the grid. The simulation results show that this configuration has less ripple current in DC-bus capacitors.