High-frequency Self-Driven Synchronous Rectifier Controller for WPT Systems

Resonant inductive coupling wireless power transfer (RIC-WPT) is the promising wireless power supply method to mobile applications. It is well-known that the efficiency and the power transfer capability of RIC-WPT systems deeply depend on the quality factor of the receiver-side resonator, which tends to decline by the conduction loss at rectifying diodes. Therefore, the synchronous rectification is one of the effective solutions. However, the unique characteristics of RIC-WPT, that is the weak magnetic coupling between the transmitter-side and the receiver-side resonator, tend to make the introduction of the synchronous rectification difficult. In order to address this issue, this paper newly proposes a self-driven synchronous rectifier controller suitable for RIC-WPT. This synchronous rectifier controller consists of basic analog elements and gate drivers, and no additional power supply is necessary for driving itself. In addition, the controller doesn’t require any information from the transmitter-side resonator. Experiments successfully verified the operating principle as well as the efficiency improvement and clarified the usefulness of the synchronous rectifier with proposed controller for practical application of RIC-WPT.