Comparison and Selection of Topology for Three Phase PV Inverters based on Power GaN Devices

Enhancement-mode Gallium nitride (GaN) power semiconductor devices have recently been explored for various applications, considering their superior performance compared to conventional Si-based devices. However, when compared to Si and Silicon Carbide (SiC) devices, GaN is limited to the current carrying capability and the limited drain to source voltage (650 V). This paper presents a methodology to perform the power converter topology selection for use in grid-connected photovoltaic (PV) inverters using GaN power semiconductors at a much higher power class (> 100 kVA) and switching frequency (> 100 kHz), which has not yet been explored in literature. The selection of topology is performed based on a novel methodology that considers both technical and economic parameters. The proposed methodology is demonstrated for a PV inverter rated at 150 kVA, with a dc link input voltage of 1000 V, operating at 140 kHz switching frequency.