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Experimental Investigation and Optimal Air Gap Selection for Electric Vehicles Wireless Charging System

Moustapha Elwalaty(1), Mohamed Jemli(2), Hechmi Ben Azza(3*)

(1) Ecole Nationale Supérieure d'Ingénieurs de Tunis (ENSIT), Tunisia
(2) Ecole Nationale Supérieure d'Ingénieurs de Tunis (ENSIT), Tunisia
(3) Ecole Nationale Supérieure d'Ingénieurs de Tunis (ENSIT), Tunisia
(*) Corresponding author



The interest for Electricals Vehicles (EV) wireless charging system has been increasing due to its simplicity of operation, robustness, and safety. The focus of this paper is on the presentation of an equivalent electrical circuit of the inductively coupled power transfer (ICPT) system. This paper proposes a new method to obtain an easier calculation of the ICPT system output power. The present method is based on the Thevenin equivalent circuit. For improving the performance of ICPT system, a relationship between the mutual inductance, the resonance frequency and the equivalent load resistance has been demonstrated in detail. This formula has been used to select the optimal air gap among transmitter and receiver coils. A prototype of a wireless charging system has been built using two rectangular coils. The resonant frequency of the designed system with a 50×20 cm transmitter coil and a 20×10 cm receiver coil is 10 kHz, and the maximum efficiency of the system is 86% at optimal air gap. Finally, the experimental results of the proposed system are presented and analyzed.
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Wireless Power Transfer; Electrical Vehicle; Inductive Coupled Power Transfer; Thevenin Equivalent Circuit

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