Efficiency improvement of 2- and 3-level inverters for distributed photovoltaic application using hybrid devices

In this paper, efficiency comparison of 2- and 3-level inverters based on a 50 kW grid-connected solar inverter is presented. A 3-level Inverter with combination of SiC MOSFET and Si IGBT is proposed. An improved switching pattern is employed to realize the zero-voltage switching (ZVS) operation for Si IGBTs. Therefore, optimal efficiency can be achieved by taking advantage of both Si-IGBT and SiC MOSFET. It shows that utilizing hybrid switches in T-type 3-level grid-connected inverters can achieve the highest efficiency. A 4 kW 3-level single phase inverter is built to verify the analysis.