Design and Assessment of an Interoperable Wireless Power Transfer System Using an Impedance-Based Method

With the recently published standard, wireless charging systems for electric vehicles (EVs) are at the stage of preparing for mass market production. In order to have success, safe, and efficient wireless power transfer (WPT) public charging needs to be ensured and therefore interoperability is a key element in the design of such systems. In this article, a design methodology based on impedance planes is presented, which enables consideration of many interoperability aspects at an early stage in the design and has a high degree of flexibility. Four impedance interfaces are presented and operational boundaries and system requirements are added at each interface to establish capability ranges, which can be transferred to any other interface and used to define and assess the design space. Furthermore, this article shows how magnetic field leakage limitations can be considered in the design process. Experimental verification of the simulations is then undertaken and an example presented of how the primary electronics for a public charging use case scenario could be assessed or designed.