High-Efficiency Operation of Wireless In-Wheel Motor at Low Load Using Intermittent Synchronous Rectification with Improved Transient Stability

The authors' research group invented a Wireless In-Wheel Motor (W-IWM) in order to overcome the low reliability of In-wheel motor's power and signal wires. This system uses Wireless Power Transfer (WPT) via magnetic resonant coupling. In order to control the WPT systems with variable power load such as motor, it is required to achieve high efficiency and transfer power corresponding to the load at any time are required. We have developed W-IWM‘s control methods to transfer desired power with high efficiency. However, the efficiency in the low power output range still has room for improvement. In this paper, novel control method using the intermittent synchronous rectification is proposed. This method improves the efficiency of the W-IWM system in low power output range by improved transient current. Experiments and simulations verify the effectiveness of the proposed method.