The Conservative Electric Field Produced by SAE J2954 Wireless Power Transfer Systems

Wireless power transfer (WPT) systems have been standardized in the SAE J2954 standard. SAE-compliant WPT systems are inductive or magnetic-field WPT systems. As such, an intense magnetic field surrounding the system would be anticipated. Moreover, this magnetic field could couple to the chassis and body of the associated electric vehicle (EV) and excite natural or characteristic modes in the EV which then could radiate more efficiently than the WPT system alone. However, it has been recently shown that for the so-called circular coupler it is the near electric field coupling to the EV that excites the most significant natural modes of the EV. More specifically, it is the conservative component of the electric field. Here, the conservative electric field of the circular coupler is examined in detail including coupling to the EV and the attendant radiation.