Multi-level inverter with a full-bridge clamp circuit for a single-phase three-wire grid

A multi-level inverter with a full-bridge clamp circuit is proposed for single-phase three-wire (1P3W) utility connected applications such as PV systems. The proposed inverter consists of two n-level inverters and a full-bridge clamp circuit. The proposed inverter requires only 12 controllable switches to obtain a five-level output voltage even though conventional multi-level converters with the grounded neutral point of the DC-bus require 16 switches. The control strategy for the proposed circuit is also discussed in this paper. The proposed circuit was confirmed to satisfy the FRT (Fault Ride Through) requirements. Finally, in the event of a load unbalance during self-sustained operation, the experimental results confirmed that the grid voltage maintained a balanced state.