Practical Design and Evaluation of a High-Efficiency 30-kVA Grid-Connected PV Inverter with Hybrid Switch Structure

Photovoltaic (PV) grid-connected inverter exposes strong challenges to its efficiency, power density and reliability. This paper presents the system-level design and test of a 30 kVA grid-connected inverter. The designed inverter achieved peak efficiency of 99.3% and a specific power of 2 kW/L by using a hybrid switch based three-level (3-L) T-type neutral point clamped (TNPC) topology. The hardware prototype presents excellent dynamic current sharing and thermal distribution during the continuous test at rated voltage and power.