Novel Thermal Management Strategy for Improved Inverter Reliability in Electric Vehicles

Featured Application Battery powered electric vehicles. Requirements for electric vehicle (EV) propulsion systems-i.e., power density, switching frequency and cost-are becoming more stringent, while high reliability also needs to be ensured to maximize a vehicle's life-cycle. Thus, the incorporation of a thermal management strategy is convenient, as most power inverter failure mechanisms are related to excessive semiconductor junction temperatures. This paper proposes a novel thermal management strategy which smartly varies the switching frequency to keep the semiconductors' junction temperatures low enough and consequently extend the EV life-cycle. Thanks to the proposal, the drivetrain can operate safely at maximum attainable performance limits. The proposal is validated through simulation in an advanced digital platform, considering a 75-kW in-wheel Interior Permanent Magnet Synchronous Machine (IPMSM) drive fed by an automotive Silicon Carbide (SiC) power converter.