Bidirectional High-Efficiency Converter Based on the Capacitive Wireless Power Transfer Technique for Electric Vehicle Charging and Energy Storage App

This article presents a transformer-less bidirectional converter, which is designed with dual resonant frequencies. It supports Electric Vehicle (EV) charging systems, via capacitive coupling wireless power transfer (CCWPT) technique. In addition, its bidirectional power transfer feature can be used to return energy to the stations of the power-wall systems. This converter smoothly operates in both voltage step-up and step-down operation modes, which provides soft switching conditions for all semiconductor switches. Capacitive coupling technique provides robust galvanic isolation between the primary and secondary sides circuits, while the transformer-less design improves its efficiency and reduces its volume and cost, significantly. The proposed converter supports both full-bridge and half-bridge configurations to adapt to diverse power transfer requirements. The cost-effective CCWPT setup enables multi-EV charging from a single station. A prototype of the given converter has been meticulously developed and experimentally validated, demonstrating excellent performance. The converter efficiently converts output power in a wide range from ۲۰۰ W to ۱۰۰۰ W, accommodates input voltage from ۳۰۰ to ۵۰۰ V, delivers a ۴۰۰ V output voltage, which is suitable for EV battery charging. It also achieves maximum efficiency value of ۹۶%, in practice.

Keywords:

Capacitive wireless power transfer , Electric vehicle charger , Resonant conversion , Step-up/down