Abstract
High-power inductive wireless power transfer (WPT) systems for electric vehicles are designed to meet specifications, such as stray field, power level, efficiency, misalignment tolerance, and ground clearance. These metrics are all heavily influenced by the coil geometry. This article proposes a coil design method based on the Fourier analysis method (FAM), which is an analytical method for directly designing coil geometries to meet stray field and power level requirements through an optimization of Fourier basis function coefficients. In this work, two 120 kW WPT proof-of-concept demonstrators with low stray field and high efficiency are built from FAM optimization results to validate the models and show the impact of the FAM design process. Experimental validation of the Generation 2 demonstrator at 120 kW output power resulted in a measured dc/dc efficiency of 97.2% at alignment with a 125 mm airgap. At the 120 kW test point, the stray fields 80 cm away from the center of the airgap between the coil assemblies were 3.4 μT(rms) on the X-axis and 3.5 μT(rms) on the Y-axis, much lower than the 27 μT(rms) ICNIRP limit.
| Original language | English |
|---|---|
| Pages (from-to) | 15295-15314 |
| Number of pages | 20 |
| Journal | IEEE Transactions on Power Electronics |
| Volume | 39 |
| Issue number | 11 |
| DOIs | |
| State | Published - 2024 |
Funding
This work was funded by Volkswagen Group Innovation in collaboration with the CURENT Engineering Research Center at the University of Tennessee, Knoxville and the Power Electronics and Electric Machinery Research Center at Oak Ridge National Laboratory. This work made use of the Engineering Research Center Shared Facilities supported by the Engineering Research Center Program of the National Science Foundation and DOE under NSF Award Number EEC-1041877 and the CURENT Industry Partnership Program. Any opinions, findings and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect those of the National Science Foundation. This manuscript has been co-authored by Oak Ridge National Laboratory, operated by UT Battelle, LLC, under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to the results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public access-plan).
Keywords
- Coil design
- Fourier analysis
- electric vehicles (EVs)
- inductive power transmission
- wireless power transfer (WPT)