Design of Long‐Distance Magnetic Coupling Resonant Wireless Power Transfer System Based on a Reconfigurable Relay Coil With a Variable Inductor

The low‐power magnetic coupling resonant wireless power transfer (MCRWPT) system, which is widely used in household appliances, experiences significant performance degradation over long transmission distances. To address this problem, a reconfigurable relay coil with a variable inductor is introduced to optimize the MCRWPT system, and a maximum power point tracking (MPPT) control strategy is used to enhance its real‐time anti‐offset performance. By adding a relay coil but not introducing the control strategy, the system's maximum transfer efficiency is enhanced from 14.95% to 58.04%, and the output power is increased from 0.3 to 8.57 W when a transmission distance is 300 mm (three times of the coil's radius) and the relay coil is located 155 mm away from the transmitting coil. When adding the reconfigurable relay coil and introducing the control strategy, the system's maximum transfer efficiency is enhanced to 61.65%, and the output power is increased to 11.34 W. The research results indicate that the proposed MCRWPT system and control strategy can effectively improve the system's transfer efficiency, output power, and anti‐offset ability under different working situations. The designed MCRWPT system can promote industrial upgrading and transformation related to wireless power transmission technology.