Power Transfer Efficiency Analysis for Omnidirectional Wireless Power Transfer System Using Three-Phase-Shifted Drive

Abstract

In order to implement the omnidirectional wireless power transfer (WPT), a novel three-phase-shifted drive omnidirectional WPT system is proposed. This system is comprised of three independent phase-adjusted excitation sources, three orthogonal transmitting coils, and one planar receiving coil. Based on the mutual coupling theory, the power transfer efficiency is derived and the corresponding control mechanism for maximizing this efficiency is presented. This control mechanism only depends on the currents’ root-mean-square (RMS) values of the three transmitting coils and simple calculations after each location and/or posture change of the receiving coil, which provides the real-time possibility to design an omnidirectional WPT system comparing with the other omnidirectional systems. In aid of computer emulation technique, the efficiency characteristic versus the omnidirectional location and posture of the receiving coil is analyzed, and the analytical results verify the validity of the control mechanism. Lastly, a hardware prototype has been set up, and its omnidirectional power transmission capacity has been successfully verified. The experimental results show that the wireless power is omnidirectional and it can be effectively transmitted to a load even though its receiving coil moves and/or rotates in a 3-D energy region.

Modeling and Experimental Analysis of Three-Dimensional Cross Coil Structure for Misaligned Wireless Power Transfer System

“…The 3D crossed structure transmitter can generate circular rotating magnetic field, and the controller of system will choose the coil of transmitter to make the maximum mutual inductance between one or several coils in transmitter and receiver during the system working time. It is worth noting that the transmitter has a variety of ways to generate circular rotating magnetic field, such as phase-shift techniques [16,17]. As for phase-shift techniques, several power supplies load different phase currents in different transmitter coils, and the magnetic field directions can be controlled by adjusting the phase of the current.…”

Resonant Network Design Method to Reduce Influence of Mutual Inductance between Receivers in Multi-Output Omnidirectional Wireless Power Transfer Systems

“…Furthermore, an omnidirectional WPT system that can generate magnetic fields in all directions to overcome the shortcomings of the limited positional freedom of the receiver in the existing planar-type WPT system was presented in [12]. Traditional omnidirectional WPT system studies are mainly aimed at transferring power to a single receiver [13][14][15][16][17][18][19].…”

Free Angular-Positioning Wireless Power Transfer Using a Spherical Joint

“…Helical-type coils made of superconductors are presented to increase the quality factor of coils [21]. Moreover, omnidirectional WPT systems are given in [22,23], and the 3D structure for a three-phase WPT system is discussed in [24]. The three-phase WPT system has found its way to some practical applications [25].…”