An Optimal Design of Contactless Power Transfer System Applied for Electric Vehicles Using Electromagnetic Resonant Coupling Junlong Duan (&) and Weiji Wang Department of Engineering and Design, University of Sussex, Brighton BN1 9QT, UK {J.Duan,W.J.Wang}@sussex.ac.uk Abstract. Over the past decades, contactless power transfer (CPT) has been acquiring considerable attentions for investigations on wireless power trans- mitting (WPT) based electric vehicles (EV) charging solutions. This paper describes a geometrically improved CPT system using innovative H-shape ferrite core prototype and electromagnetically analytical methods. In order to address the key issues such as system power transfer rating levels, maximization of system ef ficiency and charging distance of two coils, the CPT prototype in this paper focuses on operating frequencies, coupling distances and electromagnetic performances. This H-shape CPT prototype has been modelled in 3D finite element method (FEM) environment, resulting in a maximum coil transmitting ef ficiency of 63%, an optimal system ef ficiency of over 40% and a maximum RMS real power of 20.39 kW on the load end, with an air gap of 30 mm. Moreover, the H-shape system with 20-mm air gap could be measured to output an RMS real power of 31.95 kW on the load of the CPT system, achieving a maximum coil transmitting ef ficiency and overall system ef ficiency of over 77% and 47%, respectively. Furthermore, from the perspective of electromagnetics, the proposed CPT coupling design in this paper tends to appear advantages on electromagnetic field performance by analyzing the generated parameters of flux linkage, flux line distributions, magnetic flux density and so on. In addition, the limitations and future works on the CPT technologies for EV have been dis- cussed in this research paper. Keywords: Contactless Power Transfer (CPT) Á Inductive coupling Á Wireless Power Transmitting (WPT) Á Maxwell equations Á Finite Element Method (FEM) Á Ferrite cores Á Electromagnetics Á Electric Vehicles (EV) Charging Ef ficiency 1 Introduction The fundamental concepts and principles of inductive energy transmitting have been proposed and developed by Nikola Tesla, Michael Faraday and Henry Poynting in the 19 th century. Based on Maxwell’s equations and formulations in 1862 and Poytning theorem in 1884 [1], Nikola Tesla highlighted the wireless power transfer (WPT) techniques by which modern contactless power transfer (CPT) technologies and © Springer Nature Switzerland AG 2020 K. Arai et al. (Eds.): FTC 2019, AISC 1069, pp. 919–933, 2020. https://doi.org/10.1007/978-3-030-32520-6_66