Electro-Thermal Co-design of a High-Density Power-Stage for a Reconfigurable-Battery-Assisted Electric-Vehicle Fast-Charger using Multi-Physics Co-simulation and Topology Optimization

This paper presents an electro-thermal co-design and co-simulation methodology for power-electronic applications. Previous works have used co-simulation approaches to adapt thermal designs to predefined electrical loads, or vice versa. In contrast, the presented work exploits the interdependence between the domains to develop a compact thermal-management solution that leverages power-electronic control to enhance heat extraction in the presence of heat sources with different material and thermal properties. This process is shown to provide great benefit in designs that combine different power-electronic devices with different materials and thermal properties on a compact shared heatsink. The proposed methodology is applied to the design of a multi-phase current-controlled Linear Regulator (LR) as part of a custom Battery-Assisted DC Fast-Charger (BA-DCFC) architecture for electric vehicles. A topologically optimized heatsink is developed for the two different power MOSFETs comprising the LR, which leverages electrically controlled thermal balancing. A co-simulation process combining domain-specific simulation tools to obtain high-fidelity results in both electrical and thermal realms is proposed, and demonstrated for the LR system. Through co-simulation, the optimal number of parallel phases for the LR is chosen, by accurately determining the waste-heat distribution across the LR MOSFETs with the optimized heatsink for different numbers of phases. Experimental results show that the heatsink design and thermal-balance control work together to reduce the average and differences in device junction temperatures by 15% and 83%, respectively.