Multi-level inverter with H-bridge clamp circuit for single-phase three-wire grid connection suitable for Super-junction/SiC MOSFET

A multilevel inverter with H-bridge clamp circuit is proposed for single-phase three-wire (1P3W) utility connected applications such as PV system. The proposed inverter consists of two n-level inverters and a H-bridge clamp circuit. The proposed inverter features high compatibility with next generation semiconductors because the uses of a high voltage H-bridge clamp circuit at grid frequency switching. The proposed inverter requires only 12 controllable switches to obtain a 5-level output voltage. In conventional multi-level converters with grounded neutral point of the DC-bus, 16 switches are required. The control strategy is discussed in this paper. Moreover, a numerical parameter design method is considered and then verified by simulation. Finally, conduction loss of the clamp circuit is shown lower than that comparing with the conventional active neutral point clamped (ANPC) inverter using Super-junction MOSFET or SiC MOSFET.