Design of a high efficiency 22 kW wireless power transfer system for EVs fast contactless charging stations

The technology of wireless charging, also referred to as wireless power transfer (WPT) or inductive power transfer (IPT), has been successfully applied at the low power level, such as applications in the medical field or in small devices such as smart phones Along with the fast growing interest in electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs), wireless charging is becoming a new way of charging batteries. In this paper, the design of a WPT system for electrical bus fast wireless charging stations will be presented. The system is composed by a two stage switching power supply, i.e. a multiphase soft-switching buck converter controlling the output power and a high-frequency resonant full-bridge converter connected to a series-series compensation topology. The input DC voltage is around 700 V and the maximum output power is 22 kW. An analytical description of the system is reported, as well as simulations and experimental results based on a TMS320F28335 DSP are presented to confirm the effectiveness of the proposed system.