High power capacitive power transfer for electric vehicle charging applications

This paper focuses on high power capacitive power transfer (CPT) for electric vehicle charging applications. The CPT system can achieve several kW power transfer through an air-gap distance of 150 mm with the dc-dc efficiency higher than 90%. Four pieces of metal plates are used as the capacitive coupler to build up electric fields and transfer power. A double-sided LCLC compensation circuit topology is proposed for the coupler to boost the voltage on the plates. The plates can be arranged vertically, instead of horizontally, to maintain the system power at rotatory misalignment conditions. The CPT system can also be combined with the inductive power transfer (IPT) system, in which the capacitors between the plates resonate with the inductors of the coils. Three prototypes have been constructed to validate the high power CPT system, which demonstrate that the CPT technology is suitable for electric vehicle charging applications.