A Class E2 Inverter-Rectifier-Based Bidirectional Wireless Power Transfer System

In this paper, the use of class $\mathrm{E}^{2}$ inverter-rectifier (hereon known as $\mathrm{E}^{2}$ converter) system with phase-shift control for bidirectional wireless power transfer applications, is discussed. The system comprises a class E inverter, an active class E rectifier, and a set of wireless transmitter-receiver coils with series-series compensation. The power flow control of the system is achieved via the control of the phase-shift ratio between the driving signal of the inverter and that of the rectifier. To ensure zero voltage switching (ZVS) operation of the converter and precise power flow control over the full load range, the system is designed to be load-independent such that the voltage waveforms of the converter are relatively similar (slight change) regardless of the applied load. The operating principle, time-domain model, and design consideration of the system are elaborated in the paper. Simulation and experimental results are provided as preliminary verification of the derived time-domain model and the features of the system: load-independent output/input voltage waveform of the class E inverter and active class E rectifier over the full load range, ZVS operation over the full load range, providence of bidirectional and sustainable power flow control and accurate output regulation.