At present, magnetically coupled resonant (MCR) wireless power transfer (WPT) has been widely used in many practical applications. However, the traditional symmetrical coils structure has limited the development of WPT technology, such as the mining and medical field, where the coils structure is always asymmetrical because of their special environment requirements. In the study a novel method was presented for the analysis of the frequency characteristics of the MCR-WPT system with asymmetric coils structure. The concept of the quality factor ratio of the coils with asymmetrical coils structure was proposed, and then the mathematical relationship between the quality factor ratio and the output power was deduced. In addition, the effects of the quality factor ratio, generalized coupling factor, generalized mismatching factor and frequency splitting factor on the output power and transmission efficiency were studied respectively. The simulation results not only demonstrate the regular pattern between the frequency splitting, the quality factor ratio and the frequency splitting factor, but also validate the condition of the output power achieving the local maximum value. Besides, the results show the relationship between the coupling factor and the transmission efficiency. Finally, an experimental platform was built to verify the theoretical analysis. And the conclusions of the study not only provide theoretical and practical basis for the future study in WPT technology but also can provide beneficial references for the design of WPT system in particular applications. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

中文翻译：

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非对称线圈结构的MCR-WPT系统频率特性分析

目前，磁耦合谐振（MCR）无线电力传输（WPT）已广泛应用于许多实际应用中。然而，传统的对称线圈结构限制了WPT技术的发展，如采矿和医疗领域，由于其特殊的环境要求，线圈结构总是不对称的。在这项研究中，提出了一种分析具有非对称线圈结构的 MCR-WPT 系统频率特性的新方法。提出了非对称线圈结构线圈品质因数比的概念，进而推导出品质因数比与输出功率之间的数学关系。此外，品质因数比、广义耦合因数、分别研究了广义失配因子和分频因子对输出功率和传输效率的影响。仿真结果不仅证明了分频、品质因数比和分频因数之间的规律性，而且验证了输出功率达到局部最大值的条件。此外，结果显示了耦合因子与传输效率之间的关系。最后搭建实验平台对理论分析进行验证。研究结论不仅为今后WPT技术的研究提供了理论和实践依据，也可为特定应用中WPT系统的设计提供有益的参考。© 2021 日本电气工程师学会。