Six degrees of freedom wide-range IPT for multiple IoT by DQ rotating magnetic field

Abstract

Direct and Quadrature (DQ) rotating magnetic field based transmitting (Tx) coils for wireless charging of multiple IoT, which are broadly distributed over three-dimensional (3D) spaces, are newly proposed in this paper. The proposed Tx coils provide a uniformly distributed DQ magnetic field environment so that numerous IoT such as RFID, electric shelf label (ESL), and various sensors can be freely charged. By virtue of the generated DQ magnetic field, six degrees of freedom (6-DoF), regardless of their 3-axes positions and directions within 3 m distance, is satisfied by the proposed Tx coils with a plane receiving coils, which is essential for the proposed wide range ubiquitous wireless power environment. Optimum distance between DQ lines of the proposed Tx coils is found by the proposed analysis for long distance wireless power delivery together with DQ magnetic field generation, and verified by simulation and experiment with DQ Class D inverter at 6.78 MHz of switching frequency, meeting the international standard of Air-Fuel Alliance.