Two-phase Wireless Power Transfer System Using Bipolar Windings for Rotating Magnetic Fields

In this work the research is focused on the application of wireless power transfer (WPT) systems with rotating magnetic fields for charging battery-electric vehicles. Various converter topologies found in the literature were analyzed, resulting in the proposal of a single-phase AC-DC converter topology with a two-phase resonant stage. These topologies were developed with the aim of enabling the implementation of low-power WPT systems with rotating magnetic fields. Additionally, a study was conducted on different coil topologies to accommodate the rotating behavior of the magnetic field, culminating in the proposal of two two-phase coils. To obtain results, a comprehensive mathematical study was conducted, including modeling through finite element simulation software. In this process, the rotating behavior of the magnetic field between the coils was observed due to the 90° phase shift in their waveforms while at the same time leading to constant power on the in- and output of the transfer system.