A comparison of selected silicon and silicon-carbide switching devices for PV microinverter applications

Manufacturers of photovoltaic (PV) microinverters are seeking cost reductions with the goal of reaching grid parity. Wide bandgap semiconductor devices, such as silicon carbide (SiC) JFETs and MOSFETs, have technical advantages over silicon (Si) counterparts, in particular within the 200V~1200V range. Wide bandgap devices can operate at higher switching frequencies for comparable system efficiencies enabling reductions in component sizes leading to reduced system volume and cost. It is anticipated that SiC device costs and other wide bandgap devices will be competitive with Si devices in three to five years as manufacturers recoup R&D investments and reduce manufacturing costs. Thus, the main objective of this paper is to compare the performances of selected Si MOSFET, SiC JFET and SiC MOSFET for the utility interface of a dual-stage PV microinverter capable of injecting reactive power into the grid. The comparison is based on gate driver requirements, switching waveforms, thermal management needs, and efficiency.