A Novel Interleaving Method for High Power Integrated Electric Vehicle Charger with Three-Phase Permanent Magnet Synchronous Motor

The voltage of electric vehicle (EV) batteries has shifted from the conventional 400 V class to the 800 V class, necessitating boost converters to enable charging 800 V class batteries with 400 V class chargers. To reduce the additional costs associated with these boost converters, integrated chargers utilizing a traction motor and inverter have been proposed. Interleaving strategies that employ three-phase windings or only two out of the three phases have been suggested to effectively suppress battery charging current ripple. However, these strategies face challenges such as increased magnetic losses due to interleaving and higher root-mean-square current per phase when conduction is restricted to two phases. These challenges result in temperature rises in permanent magnet synchronous motors, thereby limiting both output and the duration of fast charging. This paper proposes a new interleaving method that uses threephase windings while suppressing magnetic losses for high-power charging with permanent magnet synchronous motors. The effectiveness of this method is confirmed through finite element analysis and experimental results.