Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles

Kamal Eldin Idris Elnail, Xueliang Huang, Chen Xiao, Linlin Tan and Xu Haozhe
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Kamal Eldin Idris Elnail: School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China
Xueliang Huang: School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China
Chen Xiao: Shanghai Aerospace Control Technology Institute, Shanghai 2100096, China
Linlin Tan: School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China
Xu Haozhe: School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, China

Energies, 2018, vol. 11, issue 7, 1-17

Abstract: The electromagnetic field (EMF) in a wireless power transfer (WPT) system needs to couple inductively between the primary and the secondary coils through a large air gap, thus giving the system a loosely coupled characteristic. Therefore, magnetically permeable material must be employed to improve the coupling and reduce leakage magnetic flux. However, adding an iron core increases the weight and introduces core loss as a new factor. In this paper, a WPT system model using a lumped circuit model is introduced. Moreover, the relationship between the relative permeability and the coupling coefficient in addition to the core amount (core thickness) and core loss are discussed. Three cores structure named: pot, slotted, and shaped bars cores are investigated using finite element method (FEM) software. Inspired by the investigation results, a new core structure using optimum shaped bars is proposed, the EMF level for reducing core loss in high-power transfer systems and in order to mitigate the EMF exposure to humans is intensively evaluated. The proposed core succeeded in reducing EMF and core loss by about 44% and 30%, respectively. The FEM software and physical prototype were used to validate the proposed optimum core structure. Results showed that 3.5 kW power transferred through a 20 cm air gap with 96% system efficiency(coil–coil).

Keywords: electric vehicle (EV); wireless power transfer (WPT); electromagnetic field (EMF); core structure; core loss (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (6)

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