Single Phase Five-Level Common-Ground Grid-Connected Inverter with Reduced DC link Capacitance

Abstract

This study introduces an innovative single-phase grid-connected five-level inverter design that features minimized DC link capacitor requirements while enhancing the overall power capacity of the inverter. The reduction in size of DC link capacitance is achieved by using a combination of charge pump circuits and switched capacitors. Existing common ground multilevel inverters suffer from capacitor voltage decay and imbalance, which also limits the power rating of the inverters and increases the size of DC link capacitance. The proposed topology can continuously charge the DC link capacitors, which prevents voltage decay across the capacitors, and the switched capacitor cell avoids the voltage imbalance. The proposed topology significantly reduces the size of DC link capacitors and increases the rated power capacity for common ground five-level configuration. The comprehensive analysis of the proposed topology with recent common ground multilevel topologies is presented. A simulation-based analysis is conducted to assess its performance under dynamic conditions, such as variations in load.