Improved Stress Distribution in Railway Traction Converters Using New High Power Half-Bridge Modules

Abstract:
New High Power Half-Bridge Modules have recently been introduced in railway traction converters. They are designed to minimize stray inductance and get full benefits of modern fast switching power Si IGBT and SiC MOSFET. These new standard modules available in different voltage classes offer to the user advantage of scalability and improved power ratio. Electrical and thermo-mechanical stress distribution in the converter is also important as it can impact strongly reliability and lifetime which are key requirements for railway traction applications. Thanks to advanced multi-domain simulations based on Reduced Order Model (ROM) technique and measurements, non uniformity of current and temperature stress between chips is analyzed in case of a realistic mission profile. Electrical and thermal stress distribution is improved compared to state-of-the art converters. A very good current distribution between paralleled chips is reported (# 3 %), a reduction of temperature difference between paralleled chips (typically reduced by half) is estimated with a direct impact on lifetime.