Magnetic field distribution in a WPT system for electric vehicle charging

Rui Feng, Nina Roscoe, Layth Qaseer, Mariusz Bojarski, Jaegue Shin, Dariusz Czoarkowski, Francisco De Leon, Stephen Finney, Qijun Deng

Research output: Chapter in Book/Report/Conference proceedingConference contribution book

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The objective of this paper is to discuss major factors that affect the magnetic field distribution of a wireless power transfer (WPT) system for electric vehicle (EV) charging. Both analytical and simulation approaches with a 3D finite element method (FEM) are employed to analyze the flux distribution in the system and its surroundings. The purpose of the work is to provide design guidelines for an efficient WPT system that conforms to international standards on safety and radiated EMI. To verify the obtained results, a full-scale prototype is built and tested up to 20kW power level. On the sending side, the system contains a PFC rectifier followed by a multiphase series resonant inverter connected to a transmitting coil. The receiving side is comprised of a magnetically coupled receiving coil tuned with a series-connected capacitor and a rectifier with a resistive load to emulate a battery. The coils are of a rectangular shape with 70 cm outer dimension, wound with 7 turns of litz wire, shielded with a layer of ferrite, and supported with aluminium plates. The receiving coil is attached to a steel plate that emulates a car chassis. The operating frequency of the system is 85 kHz. The calculations, simulations, and measurements are performed at various power levels and variable gap between coils (from 100mm to 300 mm). Furthermore, the effect of the coil misalignment on the magnetic field is analyzed and discussed based on two different misalignment situations. The theoretical and simulation results of this paper are in a good agreement with experimental measurements which validates the presented methodology.
Original languageEnglish
Title of host publicationProgress In Electromagnetics Research Symposium 2016
Place of Publication[Piscataway, NJ]
Number of pages1
ISBN (Print)978-1-5090-6094-8
Publication statusPublished - 8 Aug 2016
EventProgress In Electromagnetics Research Symposium (PIERS) 2016 - Shanghai International Convention Center, Shanghai, China
Duration: 8 Aug 201611 Aug 2016
Conference number: 37th


ConferenceProgress In Electromagnetics Research Symposium (PIERS) 2016
Abbreviated titlePIERS 2016
Internet address


  • WPT
  • wireless power transfer
  • electric vehicle
  • magnetic field

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