A GaN/Si Hybrid T-Type Three-Level Configuration for Electric Vehicle Traction Inverter

The inverter partial load performance is extremely important for the weighted average efficiency and vehicle mileage as during 95% of the driving time, the traction inverter for an electric vehicle is operating under < 30% full load. A GaN/Si hybrid T - Type Three-level configuration is proposed to enhance the light load efficiency. Due to the zero-reverse recovery of GaN HEMTs and the halved voltage stress across the device, the switching energy of IGBT is significantly reduced. The GaN neutral clamping leg will be disabled at full load to avoid employing full current-rating GaN HEMTs for BOM cost reduction. A GaN/Si hybrid T -type three-level phase-leg is prototyped to validate the design concept. Compared with conventional two-level configuration, the switching-on loss of IGBT in hybrid T-type configuration is reduced by about 92 %, and the switching-off loss is reduced by about 83% in the whole operating range. The system weighted-average efficiency analysis for a 150kW, 800V traction inverter is also presented.