**5. Conclusions**

In this paper, the optimal transfer efficiency of the WPT system under certain load resistance is achieved by optimizing the coil-turns number. Once the coupled coil-parameters are fixed, the load resistance to make the optimal efficiency can be adjusted and the output power can be increased by optimization design of the parameters of LCC compensation topology. The major contributions of this paper are as follows:


**Author Contributions:** F.W. conceived and designed the study, and this work was performed under the advice of and regular feedback from him. X.C. and Q.L. was responsible for the models, simulations and X.C. wrote the article. W.G. was responsible for the experiments and data analysis. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported by the Basic Research Program of Jiangsu Province (No. BK20180485), Jiangsu Provincial Key Laboratory of Smart Grid Technology and Equipment Project, and the Fundamental Research Funds for the Central Universities (No. 30919011241).

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
