Loosely coupled inductive wireless power transfer systems with class-E transmitter and multiple receivers

This paper presents a design procedure for dc-to-dc WPT systems with multiple receivers. For achieving high power-transfer efficiency, the class-E inverter and the class-E rectifiers are applied to the transmitter and the receivers, respectively. By using the numerical design algorithm, we can obtain the accurate component values for achieving the class-E ZVS/ZDS conditions and the impedance matching of the secondary side without system analyses. Additionally, the inductor designs are discussed from the magnetic-component design knowledge [13]. The WPT system with five receivers was designed and circuit experiments were carried out. The power-transfer efficiency was 84.4 % with 5.7 W output power in total.