Enhanced Performance of On-board EV Battery Charger with Universal Power Supply

Abstract

This paper is intended to provide enhanced features of onboard EV battery chargers in terms of improved power quality feature, reduced voltage stress, reduced filter size, high efficiency and fast dynamic response for universal input voltage range (85–265 V). The proposed configuration comprises of three-level quadratic converter suitable to provide high voltage gain. The detailed operation, analysis and control scheme of the proposed converter rated for 3.2 kW, 400 V are studied under simulation and hardware in a loop environment. The on-board charger performances are assessed by charging a 40 Ah lithium ion EV battery under different charging modes. The state of charge of battery decides converter operating mode i.e. constant current and constant voltage mode to charge the battery. Enhancement in the onboard charger is observed in both operating modes tested for wide variation in supply voltages. The results reveal that the operation of converter depicts unity power factor operation, improvement in supply current harmonics and controlling output voltage/current. Under both operating modes, the proposed charger draws sinusoidal supply current from ac mains and its THD is reduced to specified limit prescribed by IEC-61000-3-2. Furthermore, the charger performance is also investigated for EV battery charging operation at wide input voltage variations and found satisfactory.