Efficiency Evaluation on a CoolMos Switching and IGBT Conducting Multilevel Inverter

This paper deals with a three-level inverter topology in the 3kW range as an alternative to commonly used three-level topologies. The topology is attractive for having low switching losses due to the utilization of CoolMos switching devices while keeping conduction losses low due to the utilization of IGBTs. A proper time delay between the CoolMos and IGBT devices increases the efficiency by 0.2 %. Maximum efficiencies of 97.7% are achieved and less than 0.2%efficiency degradation is possible with doubled switching frequency. The case temperatures of the switching devices are below 60 °C at full power.