Design of an 11 kW power factor correction and 10 kW ZVS DC/DC converter for a high-efficiency battery charger in electric vehicles

Usually a battery charger for the electric vehicle consists of a power factor correction (PFC) and a DC/DC converter, both of which require the high-efficiency operation. In this study, a three-phase 11 kW full-bridge PFC is designed to transform the grid voltage to 400 VDC and reach the grid-side power factor equal to 1. This circuit adopts the symmetric space vector pulse width modulation, which effectively decreases the electrical stress of switches compared with other algorithms. The generated 400 VDC directly drives a CoolMOS-based 10 kW full-bridge DC/DC converter, that utilises the zero-voltage-switching technique to maintain the high efficiency. Experimental results validate that (i) the PFC part could reach 97-98% efficiency from 5 to 10 kW and (ii) the efficiency of the DC/DC part could reach 97%at10 kW for 200-400 V output and 95.9% for 400-450 V output. Fast reverse recovery diodes and SiC Schottky diodes are also experimentally compared in this prototype.