Multi-Objective Design Optimization of EV Inverter for Efficiency, Volume, and Reliability

Electric vehicle (EV) traction inverters require an optimized balance between high efficiency, compact volume, and long-term reliability to ensure a seamlessly integrated design and robust performance across diverse driving scenarios. However, achieving this balance is challenging due to the complex interdependencies among mechanical, electrical, and thermal subsystems within the EV drivetrain. To address these challenges, this paper presents a multi-objective optimization study that evaluates the design trade-offs between efficiency, volume, and reliability. Leveraging a genetic algorithm (GA)-based approach, the proposed approach explores a wide design space and identifies Pareto-optimal solutions that balance these competing objectives. The optimization study considers key design parameters, including DC-link capacitance, battery voltage, operating frequency, junction temperature rise, ripple voltage, and the selection of semiconductor material (silicon, Si or silicon carbide, SiC). These factors directly influence inverter efficiency, power module reliability, and total volume, including heatsink and capacitor sizing. A high-fidelity and multi-domain EV simulation model has been developed to capture both transient and steady-state vehicle dynamics, while evaluating the inverter performance under varying driving conditions. Simulation results of the Pareto frontier demonstrate pronounced trends; optimizing higher efficiency often demands increased component volume for improved filtering and thermal management. Enhancing reliability requires limiting junction temperature rise, which favors conservative operating conditions and larger system size. On the other hand, minimizing volume imposes thermal and electrical constraints that degrade both efficiency and reliability. The results provide information regarding feasible sets of design parameter combinations, enabling the identification of optimal strategies for next-generation EV traction inverters that are compact, energyefficient, and reliable.