A Multirelay Magnetic Coupling Wireless Power Transfer System With Hybrid Output Characteristics

A multirelay magnetic coupling wireless power transfer (WPT) system with hybrid output characteristics has been proposed in this article. There are two modules. Each module is formed by a relay coil and a load coil, and in series with a compensation capacitor. The coupling between different modules is strengthened by ferrites. The WPT system is modeled and analyzed based on the quadratic eigenvalue problem (QEP). The variation of eigenvalues with load resistance is analyzed, and the operating frequency of hybrid output characteristics can be directly obtained. As long as the WPT system works at the operating frequency of hybrid output characteristics, one module has the constant voltage (CV) output characteristic, and the other module has the constant current (CC) output characteristic. No high-order compensation network or additional control is required. The output characteristics are compared in terms of frequency sensitivity and the attenuation of system output with the load variation. An experimental prototype is built. The experimental results validate the correctness and feasibility of the theoretical analysis and the proposed methodology.