Investigation of the zero-current switched class E converters for automotive wireless power transfer inductive charging applications

The zero-current switched class E converters are investigated for automotive wireless power transfer inductive charging applications. In comparison to the class D converters, typically used for this application, the class E converters have only one active switch on the primary-side of the inductive energy transfer coils and the resonant tank current magnitude is independent from the magnitude of the current in this active switch. The paper presents full details of the Class E² converter analyses including converters with series and parallel resonant circuits and compares the two topologies. A full-size prototype converter has been built and tested to confirm theoretical predictions. The converter performance is investigated, when operated with the required variation of the magnetic coupling, battery-voltage and output power level determined by the automotive charging application.