Development of a power dense and environmentally robust traction power inverter for the second-generatio chevrolet VOLT extended-range EV

Abstract

By significantly re-engineering to reduce physical size and mass of the traction power inverter module (TPIM) for 2nd generation Chevrolet VOLT Extended-Range EV it is possible to mount the inverter to the transmission and meet all performance targets, maintain high reliability and environmental robustness. The Chevrolet VOLT is an electric vehicle with extended-range. It is capable of operation on battery power alone, and on hybrid/ engine power after depletion of the battery. 1st generation Chevrolet VOLTs (VOLT-1) were driven over half a billion miles in North America from October 2013 through September 2014, 74% of which were all-electric [1, 12]. For 2016, GM has developed the 2nd generation of the VOLT (VOLT-2) vehicle and “Voltec” propulsion system. This effort by GM and Delphi provides a significant cost benefit to the overall system by eliminating costly AC traction cables. Effort was taken to the electrical design of the power switch to achieve efficiency target and thermal challenges. A novel cooling approach enables high power density while maintaining a very high overall conversion efficiency. Design focus was applied to the mechanical design of this TPIM to provide extremely stiff frame required for reliability in the transmission environment and reduce integration cost.