The efficiency of a wireless power transfer (WPT) system is highly dependent on the load resistance. However, the load resistance, such as the battery, is not constant during the charging process. Therefore, a crucial challenge for a WPT system is to keep high efficiency over wide load range. In this work, a hybrid load matching method for WPT systems is proposed to achieve high efficiency. The basic principle of this system is to use a hybrid load matching method, i.e., adding an L{L} – C{C} resonant matching network and choosing the rectifier operation modes (full-/half-bridge), to convert the load to an optimal range. Then, the system efficiency can be kept at the top regions of the efficiency curves. Finally, a prototype is built to validate the performance of the WPT system with the proposed approach. The experimental results show that the optimal load of the WPT system can be transformed from 30 to 60, 120, and 240 Ω\Omega , and the efficiency of the proposed system can be maintained above 89% from 10 Ω\Omega (527.8 W) to 600 Ω\Omega (8.64 W).

中文翻译：

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WPT 系统在宽负载范围内保持高效率的混合负载匹配方法


无线功率传输 (WPT) 系统的效率高度依赖于负载电阻。然而，负载电阻，例如电池，在充电过程中并不是恒定的。因此，WPT 系统面临的一个关键挑战是在宽负载范围内保持高效率。在这项工作中，提出了一种 WPT 系统的混合负载匹配方法以实现高效率。该系统的基本原理是采用混合负载匹配方法，即增加一个L{L} – C{C}谐振匹配网络并选择整流器工作模式（全桥/半桥）来转换负载到最佳范围。然后，系统效率可以保持在效率曲线的顶部区域。最后，建立了一个原型来验证所提出的方法的 WPT 系统的性能。实验结果表明，WPT系统的最佳负载可以从30Ω\Omega转变为60Ω\Omega、120和240Ω\Omega，并且所提出的系统的效率可以从10Ω\Omega（527.8W）保持在89%以上。至 600 Ω\Ω (8.64 W)。