Analysis and experimental verification of two types of three‐coil MCR‐WPT system with constant current and constant voltage characteristics

Abstract In order to achieve an optimized design of a three‐coil wireless power transfer (WPT) system with constant voltage (CV) and constant current (CC) output characteristics, meeting the power supply demands of rechargeable loads for CV/CC, this paper conducts an in‐depth research on the three‐coil magnetically coupled resonance (MCR) WPT system. A novel method for CV/CC output switching under the MCR‐WPT system is proposed. Firstly, a coupled inductance model is established, and the compensation parameter expressions of both single‐transmitter single‐receiver (STSR) three‐coil WPT system with relay coil and double‐transmitter single‐receiver (DTSR) three‐coil WPT system are derived. A compensation network parameter design method to achieve zero phase angle (ZPA) condition is proposed. This proposed three‐coil WPT system can achieve CV/CC output switching by a single alternating current (AC) switch. The transmission characteristics of these two MCR‐WPT systems are analyzed, and the transmission efficiency and lateral offset capability of the systems are compared. Experimental results demonstrate stable energy transfer of the system, validating the correctness and effectiveness of the proposed system's CV/CC output characteristics and parameter design methods. The results indicate that the proposed system can achieve stable CV/CC output.