Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles
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 t...
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doaj-3feb5a2a401542d981856a7dccc6f1532020-11-24T21:43:44ZengMDPI AGEnergies1996-10732018-07-01117173410.3390/en11071734en11071734Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric VehiclesKamal Eldin Idris Elnail0Xueliang Huang1Chen Xiao2Linlin Tan3Xu Haozhe4School of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, ChinaSchool of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, ChinaShanghai Aerospace Control Technology Institute, Shanghai 2100096, ChinaSchool of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, ChinaSchool of Electrical Engineering, Southeast University, No. 2 Sipailou, Nanjing 210096, ChinaThe 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).http://www.mdpi.com/1996-1073/11/7/1734electric vehicle (EV)wireless power transfer (WPT)electromagnetic field (EMF)core structurecore loss |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Kamal Eldin Idris Elnail Xueliang Huang Chen Xiao Linlin Tan Xu Haozhe |
spellingShingle |
Kamal Eldin Idris Elnail Xueliang Huang Chen Xiao Linlin Tan Xu Haozhe Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles Energies electric vehicle (EV) wireless power transfer (WPT) electromagnetic field (EMF) core structure core loss |
author_facet |
Kamal Eldin Idris Elnail Xueliang Huang Chen Xiao Linlin Tan Xu Haozhe |
author_sort |
Kamal Eldin Idris Elnail |
title |
Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles |
title_short |
Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles |
title_full |
Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles |
title_fullStr |
Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles |
title_full_unstemmed |
Core Structure and Electromagnetic Field Evaluation in WPT Systems for Charging Electric Vehicles |
title_sort |
core structure and electromagnetic field evaluation in wpt systems for charging electric vehicles |
publisher |
MDPI AG |
series |
Energies |
issn |
1996-1073 |
publishDate |
2018-07-01 |
description |
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). |
topic |
electric vehicle (EV) wireless power transfer (WPT) electromagnetic field (EMF) core structure core loss |
url |
http://www.mdpi.com/1996-1073/11/7/1734 |
work_keys_str_mv |
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