A Novel Constant Voltage Three‐Coil Wireless Power Transfer System With Current Autonomous Distribution and Voltage Enhancement Capability

ABSTRACT As the development of electrical vehicles (EVs), apart from the transmission efficiency improvement, higher charging voltage is also needed to accelerate the charging speed. In this paper, a single‐transmitter and dual‐receiver wireless power transfer (WPT) topology is proposed to achieve load‐independent constant voltage output and input zero phase angle. The receiving coil is divided into two windings: one couples with the primary transmitting coil and the other winding, while the other minimizes its coupling with the primary transmitting coil. In addition, the two windings are connected to two bridge legs of the rectifier, respectively. Owing to the secondary connection structure, the charging voltage of the whole WPT system can be enhanced by at least double. Furthermore, the current of the two receivers can be distributed automatically with the variation of the equivalent load value. Owing to the shunt effect of the two receiving windings, the power loss within the receiving circuits can be greatly reduced. In addition, an integrated coupler is designed to avoid unwanted cross‐coupling. Finally, an experimental platform is built to verify the actual performance of the proposed three‐coil WPT system.