A Power-Enhanced Large-Space Wireless Charging System with Relay Energy Conversion Structure

Large-space wireless power transfer (WPT) technology can realize free space wireless power transmission while ensuring electromagnetic safety. However, the power transmission capability of the system is weakened by corresponding non-uniform weak magnetic field. To surmount these limitations, this paper proposes a novel power-enhanced large-space wireless charging system, which can achieve a wide spatial uniform magnetic field that can satisfy the safety requirements, and realize a stable output power of tens of watts across an extensive spatial domain through the relay energy conversion structure. The system design scheme and corresponding solution are introduced. The large-sized coils are compensated in segments to achieve uniform magnetic field. The compact relay energy conversion structure with both receiving and transmitting capabilities is analyzed. The energy of surrounding space is initially captured by the receiving coil in the relay structure and subsequently converted into higher frequency alternating current, seamlessly transferred to the transmitting coil in the relay structure, and ultimately transmitted to the receiving device. In this way, the transmission power can be improved through the two-stage energy conversion structure. The transmission characteristics of the system are derived and analyzed, confirming its effectiveness through simulation and experiment. The results demonstrate that the system can significantly enhance the transmission power capability under the electromagnetic safety standards. The experimental results show that within a space of about 25 m3, the system can be charged anywhere, and the charging power is about 18 W.