Novel Output Regulation Method for Three-Phase Three-Level Wireless EV Charging System
Yuxin Liu, Chunhua Liu, Xingran Gao, Yang Xiao
Abstract
Three-phase wireless power transfer (WPT) systems have compact coil structures, canceled triplen harmonics, and less dc -link current ripple, which are suitable for wireless electric vehicle (EV) charging systems. Most three-phase WPT systems are based on two-level inverters. Alternately, three-level (TL) inverters have the potential to further promote the performance of EV chargers by reducing the electromagnetic interference (EMI) and the voltage stress of power switches. However, the unbalance of the neutral point (NP) voltage is a problem for traditional TL inverters. This article proposes a TL three-phase WPT system for EV wireless charging, which is based on a T-type neutral point clamp (TNPC) inverter. The modeling, coil structure, and switching pattern of the proposed system are analyzed in detail. Furthermore, a novel output regulation method based on vector control is proposed for the WPT system. Also, a NP voltage balance strategy is proposed to enhance the reliability of the TL inverter. Both simulations and an experimental prototype based on SIC- MOSFET are given to verify the effectiveness of the proposed three-phase WPT system and control method.