Enhancing temperature uniformity in power modules used in a 4-in-1 power electronics converter

The rapid electrification of the automotive industry is driving stringent requirements for power electronic converters in terms of power density, compact packaging, weight reduction, and operational reliability. X-in-1 architectures address these demands by integrating multiple onboard power conversion functions into a unified platform. However, existing thermal-management studies largely focus on isolated power modules or simplified loading conditions and therefore do not fully capture the mode-dependent and spatially non-uniform semiconductor losses encountered in highly integrated multi-functional converters. This work investigates the thermal performance and design trade-offs of a 4-in-1 converter integrating the traction inverter, DC boost charger, on-board charger, and auxiliary power module. The objective is to quantify loss-driven temperature variation across SiC devices under various operating modes and to evaluate cooling strategies for mitigating this imbalance. Device-level losses associated with the three operating modes are incorporated into computational fluid dynamics models to predict the resulting junction-temperature distributions. Two cooling strategies, conventional cold-plate cooling and jet impingement cooling, are comparatively assessed in terms of thermal and hydraulic performance. The jet-impingement configuration is optimized using a multi-objective genetic algorithm subject to a maximum junction-temperature limit of 150 °C and a pressure-drop target of 10 kPa. Under traction conditions, the optimized jet-impingement configuration improves die-level temperature uniformity by 66.7% compared with the cold plate, with a corresponding 35.5% increase in pumping power. This reduction in die-to-die temperature gradient promotes more uniform thermo-mechanical loading across the module, thereby addressing a key reliability concern in high-power-density SiC converters. The contribution of this study is the incorporation of mode-specific semiconductor loss distributions into the thermal design of a dual-sided 4-in-1 converter, enabling cooling performance to be assessed based on die-level temperature uniformity.