SiC + Si three‐phase 48 V electric vehicle battery charger employing current‐SVPWM controlled SWISS AC/DC and variable‐DC‐bus DC/DC converters

Abstract

Wide-bandgap (WBG) devices such as SiC and GaN switches are regarded as next-generation power semiconductors, due to their superior performance over conventional Si devices, for instance, a low switching loss and high thermal conductivity. Its bottleneck, however, is the high cost, which is critical for renewable energy and automotive industries. This study adopts SWISS AC/DC rectifier topology for the three-phase 380-480 VAC along with an isolated DC/DC converter, indicating such topology can maximise the advantages of Si (low conduction loss) and SiC (high switching loss), altogether thereby yielding the high performance and low cost. A novel space-vector pulse width modulation (SVPWM) was proposed to control such a current-source power factor correction, where only two SiC devices were adopted for the DC-bus voltage control. The closed-loop control of the grid current is realised for the unity power factor. Such topology further allows the DC-bus voltage to be varied with the output voltage, thereby minimising the system loss. A final prototype was built to charge a 48 V battery at 11 kW. Experimental results validated the effectiveness of such battery charger design.