Design methodology of the power receiver with high efficiency and constant output voltage for megahertz wireless power transfer

Megahertz (MHz) wireless power transfer (WPT) has been widely studied due to its lighter and more compact system and higher spatial freedom. This paper proposes a design methodology of the power receiver with high efficiency and constant output voltage in MHz WPT systems. The power receiver consists of four parts, the receiving coil, the Class E rectifier, the buck converter and the DC load. Firstly, the inductance, equivalent series resistance (ESR) and the coupling coefficients are formulated based on the physical model of the coupling coils. The Class E rectifier and the buck converter are also derived and analyzed. Secondly, the receiving coil and the Class E rectifier are designed and optimized simultaneously to maximize the efficiency while the buck converter is designed to works in a self-regulation mode to provide the constant output voltage. The system parameters design is formulated as an optimization problem and solved using the Genetic Algorithm (GA). Finally, simulation tool Advanced Design System (ADS) is used to verify the proposed design methodology.