Wireless Power Charger Based on Class E Amplifier with the Maximum Power Point Load Consideration

Abstract

The construction of an electromagnetic coupling power transfer system is introduced in this paper. Considering the characteristics of the battery charger, a novel parameter design method based on the load of the maximum power transfer point is proposed. Then, the compensator, resonant circuits, and some key parameters of the electromagnetic coupler are discussed in detail by constructing a mutual inductance model to carry out impedance calculation and analysis. Coupling coefficient influenced by different magnetic circuits and coil distribution were analyzed by building a finite element model and an equivalent magnetic circuit. Moreover, impedance matching and compensation network parameters were theoretically calculated and simulated. Finally, a wireless power charger based on an open-loop class E amplifier with the maximum power point load consideration was manufactured. Simulation and experiments were done to verify the analyses, and the capability of 4.2 W power delivery at a distance of 10 mm and a peak system efficiency exceeding 72% were demonstrated.

Keywords

• class E amplifier
• electromagnetic coupling
• finite element analysis
• impedance matching