High efficiency three level transformerless inverter based on SiC MOSFETs for PV applications

Transformerless inverters are widely employed in PV grid-tied inverter due to their capability of reducing power losses and enhancing the system efficiency. Several multilevel transformerless topologies are investigated to increase power quality and system efficiency. Wide bandgap power devices such as SiC MOSFETs can increase the system performance and reduce the total losses due to their superior features over Si switching devices. In this paper, a three level transformerless inverter based on H6 topology is proposed. The proposed topology is implemented with a silicon carbide (SiC) MOSFETs and a modulation approach is adopted to reduce the number of conducting switches. Simulation results show that total conduction and switching losses are reduced by about 50% and the efficiency of the system is increased by 3% at a high switching frequency of 100 kHz.