An Active Switched-Capacitor Half-Wave Receiver With High Efficiency and Reduced Components in WPT System

There is an increasing attention on wireless power transfer (WPT) technology in many applications. However, for WPT systems, the changing coils distance and variable load make the output power fluctuant. In this article, a switched-capacitor-based half-wave rectifier with active impedance matching ability is proposed in the WPT system to solve the issue. Different from typical half-wave rectifier, the conducting time of the diode in the proposed topology becomes adjustable, making the equivalent impedance controllable. Compared with the universal methods, where an additional dc-dc converter located at the end of the rectifier for power adjustment, fewer components are employed and soft-switching is achieved for the rectifier switch in the proposed topology, leading to lower cost, higher power density, and higher efficiency. In the theoretical analysis, the operation principle is given and the relationship between the diode conducting time and the equivalent load is obtained. A prototype was built to verify the performance of the proposed topology, the experiments agree with the calculation well.