INTRODUCTION General Motors (GM) was the first in modern days to offer complete electrification when it's Battery Electric Vehicle (BEV) EV1 was introduced in 1996 [ 3]. Subsequently GM is enhancing level of electrification [ 2] by introducing hybrid electric vehicle (HEV), plug-in HEV (PHEV), Extended Range EV (EREV) 1st Generation VOLT [ 5,8] and most recently 2nd Generation VOLT. Optimal design of TPIM power electronics is one of the enablers to achieve aggressive fuel-economy, performance, reliability, cost and mass targets for these electrified vehicles. EREV , first introduced by GM [5], has full functionality as an EV , better electrification than PHEV and blended operation of gas and electricity as necessary. EREV electric drive system contains two PM motors that are commuted by two traction inverters, PIM-A (power inverter-A), PIM-B (power inverter-B) and an oil pump motor run by a third inverter. All these three inverters are contained in one package named TPIM situated between electric motors and battery.A comprehensive analysis, design and validation plan was tailored to the 2nd Generation VOLT TPIM. Worst-case analyses were performed and confirmed with a comprehensive early design demonstration. Thermal measurements were made to understand the effectiveness of cooling design and to map peak temperatures and gradients predicted analytically. In addition, design failure modes and effects analysis were used to refine the design. This paper focuses on system architecture, power electronics component design optimization, efficiency, size, cost, performance and safety of 2nd Generation VOLT TPIM. Mechanical interfaces, assembly features and environmental robustness of the TPIM are also presented in this paper. Section-II describes propulsion, electric drive and HV system requirements overview. Section-III presents power electronics design optimization, power stage selection criteria, TPIM performance, thermal robustness and efficiency metrics. Mechanical orientation, stiffness/ vibration robustness features of TPIM and transmission assembly features, coolant interface are discussed in Section-IV . Section-V compares features between 1st Generation VOLT and 2nd Generation VOLT TPIMs. System and TPIM level test results are included in Section-V . Figure 1 shows 2nd Generation VOLT HV components vehicle layout.Power Dense and Robust Traction Power Inverter for the Second-Generation Chevrolet Volt Extended-Range EV Mohammad Anwar General Motors Corporation Monty Hayes Delphi Electronics & Safety Anthony Tata, Mehrdad Teimorzadeh, and Thomas Achatz General Motors Corporation ABSTRACT The Chevrolet V olt is an electric vehicle with extended-range that is capable of operation on battery power alone, and on engine power after depletion of the battery charge. First generation Chevrolet V olts 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 second-generation of the V olt vehicle and “V oltec” propulsion system. By significantly re-engineering the traction power inverter module (TPIM) for the second-generation Chevrolet V olt extended-range electric vehicle (EREV), we were able to meet all performance targets while maintaining extremely high reliability and environmental robustness. The power switch was re-designed to achieve efficiency targets and meet thermal challenges. A novel cooling approach enables high power density while maintaining a very high overall conversion efficiency. CITATION: Anwar, M., Hayes, M., Tata, A., Teimorzadeh, M. et al., "Power Dense and Robust Traction Power Inverter for the Second- Generation Chevrolet V olt Extended-Range EV ," SAE Int. J. Alt. Power. 4(1):2015, doi:10.4271/2015-01-1201.2015-01-1201 Published 04/14/2015 Copyright © 2015 SAE International doi:10.4271/2015-01-1201 saealtpow.saejournals.orgFigure 1. 2nd Generation VOLT H