Enhancement Method of Weak Transmission Area for Omnidirectional Wireless Power Transfer System

Reducing the weak transmission area (WTA) of omnidirectional transmitter in wireless power transfer is a challenge. In this paper, we propose a method to enhance the WTA with nonorthogonal coils, and two types of transmitters are made, the 90° sandglass Tx and the 20° sandglass Tx. Specifically, a single power source is utilized to drive the current of Tx without phase and current control methodology. Power is transmitted to the receiver through magnetic resonant coupling in 50 mm. In addition, an equivalent circuit model of the sandglass Tx system is derived and mathematically analyzed. The magnetic induction density of the sandglass Tx system is evaluated via analysis and experiments. Finally, practical experimental results from the resonant coupling system confirm the theoretical analysis.