Abstract
The mass and volume of wireless power transfer (WPT) systems for charging electric vehicles are directly related to the rated power of the system. The difficulties of high-power wireless charging are exacerbated by the need to meet the same practical constraints associated with vehicle integration as lower power systems. Therefore, more advanced techniques are necessary to improve power density and specific power of wireless charging systems for high-power applications. This article presents theory and analysis of three-phase inductive WPT systems with bipolar phase windings. Magnetic coupler topologies and the theoretical and practical aspects of series three-phase resonant compensation networks are discussed. The systems under consideration are designed to utilize rotating magnetic fields to achieve a power transfer characteristic that is temporally smoother than single-phase systems. Other benefits associated with rotating magnetic field based WPT, including reduced ferrite mass, filter component requirements, and electromagnetic field emissions, are discussed. Experimental results of a prototype system are presented in both aligned and misaligned configurations. The system is demonstrated transferring 50 kW with 95% dc-to-dc efficiency over a 150-mm airgap in the aligned case. On a per-pad basis, the magnetic couplers achieve a power density of 195 kW/m^2 and a specific power of 3.65 kW/kg. This article is accompanied by a video of the rotating magnetic field produced by a simulated three-phase WPT system.
| Original language | English |
|---|---|
| Article number | 8863954 |
| Pages (from-to) | 4500-4517 |
| Number of pages | 18 |
| Journal | IEEE Transactions on Power Electronics |
| Volume | 35 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2020 |
Funding
Technology Laboratory (NETL), and the National Renewable Energy Laboratory (NREL) for their contributions to this work: Randy Wiles (ORNL) for mechanical design of the inverter and rectifier assemblies; Larry Seiber (ORNL) for construction of the inverter and rectifier; Jonathan Wilkins (ORNL) for design and construction of the coil aligment system and capacitor configurations; Laurie Varma (ORNL) for technical editing support; Andrew Meintz (NREL) for reviewing an early draft of this manuscript; Burak Ozpineci and David Smith (both of ORNL) for their managerial support and technical guidance; and Lee Slezak (DOE) and Jason Conley (NETL) for funding this work and project guidance. This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). This research used resources available at the Power Electronics and Electric Machinery Research Facility, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory (ORNL). The authors would like to thank the following people from ORNL, DOE, the National Energy
| Funders | Funder number |
|---|---|
| Andrew Meintz | |
| US Department of Energy | |
| U.S. Department of Energy | |
| Oak Ridge National Laboratory | |
| National Renewable Energy Laboratory |
Keywords
- Electric vehicles (EVs)
- inductive charging
- resonance
- three-phase electric power
- tuned circuits
- wireless charging
- wireless power transfer (WPT)
