Design Considerations of GaN Transistor Based Capacitive Wireless Power Transfer System

Abstract

The paper discusses and evaluates design of capacitive wireless power transfer (WPT) system. The capacitive WPT can replace a conventional inductive WPT for example in applications where metallic objects are placed close to receiver or transceiver. Main limitation for wider application of the capacitive WPT is due to small coupling capacitance between two surfaces in limited space. Therefore, to utilize capacitive WPT system the switching frequency should be as high as possible. Challenges associated with design of capacitive WPT system operating in MHz range are discussed in this paper. In the paper it is described WPT system that consists of two copper plates to transfer power from the primary side to the secondary side. Some calculation considerations of resonant network is given in the paper. The high switching of inverter transistors requires high performance transistors with optimized driver circuit. The design of GaN transistor based inverter and driver circuit is discussed and experimental results are shown.