A 3kW Single-Ended Wireless EV Charger with a Newly Developed SiC-VMOSFET

Abstract

In this paper, a high- power single-ended wireless EV charger with a development of new SiC-VMOSFET is described. In the first place, the circuit configuration of a wireless EV charging system operating on a single device is described. In the second place, loss evaluations of SiC-IEMOSFET (Implantation & Epitaxial MOSFET) and Si-IGBT in a wireless EV charger under international standard frequency operation are compared with each other. The operating frequency of the previous system was 25kHz to avoid audible noise, but the global standard decided the 85kHz band of standard operating frequency for wireless EV chargers. Indicated is that SiC-MOSFET is suitable for single-ended 85kHz band wireless EV chargers. In the third place, discussed is a high-power single-ended wireless EV charger with a newly developed SiC-VMOSFET (V-groove trench MOSFET). Transfer power of 3kW is required for a practical normal type EV charging although the previous developed charger has 1kW transfer power with a 1200V SiC-MOSFET. A high voltage devise of 1700V withstand voltage is necessary for a 3kW single-ended wireless EV charger. In general, since on-resistance of MOSFETs is proportional to the square of withstand voltage, very high conduction loss of high voltageMOSFET make the implementation difficult. Indicated is that a newly developed SiC-VMOSFET is the solution of this problem. Described are experimental results of power devise losses in a developed 3kW single-ended wireless power transfer converter. In the final place, in order to secure the reliability of power switching device, avalanche resistances are comparative evaluated between SiC-VMOSFETs and previous SiC-MOSFETs.