An Integrated Charger of Wireless Power Transfer, Onboard Charger, and Auxiliary Power Module for Electric Vehicles

The rapidly developing electric vehicles (EVs) calls for improvement in the charging system for the high-voltage (HV) and low-voltage (LV) batteries in EVs. In the conventional EV charger, wireless power transfer (WPT), onboard charger (OBC), and auxiliary power module (APM) are three separate structures. This article proposes an integrated charger for WPT, OBC, and APM by sharing power conversion stages with the advantages of cost effectiveness and high-power density. The transformer of OBC can be seen as two strongly coupled coils, and the secondary-side coil can be loosely coupled with the transmitting coil of the WPT system, serving as a receiving coil. A transformer can be employed on the receiving side to integrate the APM with WPT. In this way, the receiving coil, the compensation network, and the power electronics converter can be shared. The integrated structure can work in three modes. In the first mode (wireless charging mode) and the second mode (conductive charging mode), the utility delivers power to the HV and LV batteries simultaneously. In the third mode (HV-LV mode), the LV battery is charged by the HV battery through APM. An experimental prototype is implemented to validate the proposal.