Analysis and Design of Wireless Power Transfer System with Asymmetrical Duty-Cycle Controlled Class-D ZVS Inverter

This paper presents a wireless power transfer system with the asymmetrical duty-cycle controlled class-D zero-voltage switching (ZVS) inverter and class-E rectifier along with its analytical expressions and the design procedure. In the asymmetrical duty-cycle control, the resonant current of the inverter contains harmonic components. In the analysis, harmonic components of resonant current are considered. Additionally, MOSFET anti-parallel diode effects are included in the analytical expressions for expressing the ZVS operation. As a result, the accurate steady-state waveforms can be obtained from the analytical expressions. This paper also shows the control strategy against load variations, which is one of the useful applications of the analytical expressions. The validity of the analytical expressions and the effectiveness of the proposed control strategy were confirmed by a quantitative comparison with experimental waveforms.