Cascaded Boost-Class-E for rotary capacitive power transfer system

This paper presents a capacitive power transfer (CPT) system design for low-power rotary applications. The aim of a rotary CPT system is to be free of power cables so it can achieve 360 degrees of free rotation, while remaining simple and easy to clean. In this work, a class-E high-frequency inverter with second-order LC compensation is proposed to drive the rotary CPT system. An LC compensation circuit is applied on both stationary and rotating sides in order to maximise the power transfer by increasing the voltage across the coupling plates. By implementing the proposed technique, the Class-E LCCL rotary CPT system that is efficient and less sensitive to load variations can be achieved. A Boost converter is also proposed here to provide input impedance matching and tune the input power of the Class-E LCCL rotary CPT system. A 10W multiple plate rotary CPT prototype based on cascaded Boost- Class E LCCL is designed and implemented to demonstrate efficient wireless power transfer (WPT) across the rotating load. The results reveal >76% power transfer efficiency is successfully achieved at 1MHz operating frequency and with 7.67W output power.