Spherical Flux Concentration Transmitter for Omnidirectional Wireless Power Transfer with Improved Power Transmission Distance

In this paper, we propose a spherical flux concentration structure for omnidirectional wireless power transfer. Omnidirectional wireless power transfer technology is a method that can transmit power to a transmitter located in arbitrary position in a two-dimensional or three-dimensional space. However, in order to improve power transfer distance in wireless power transfer system, the diameter of the coil or the number of windings must increase, thereby increasing the size of the transmitter. The transmitter structure proposed in this paper adds a ferrite core inside the transmitter coil so that the magnetic flux generated by the transmitter is directed in the position of the receiver. As a result, the flux linkage increases and the mutual inductance increases. By implementing the omnidirectional wireless power transfer system using the proposed structure, the power transfer distance can be improved by 65% compared to the existing system without increasing the size of the transmitter. Simulation shows that the proposed spherical flux concentration structure increases the mutual inductance when applied to omnidirectional wireless power transmission system.