Radial-Flux Rotational Wireless Power Transfer System With Rotor State Identification

A radial-flux rotational wireless power transfer (RF-R-WPT) system with rotor state identification function has been proposed to provide power to the devices mounted on a rotating shaft in this article. It can not only transmit electric power from the stationary side to the rotating side but also monitor the rotor state at the same time, improving the stability, security, and service life of the traditional brushes and slip rings. First, the topology and operation principle of the RF-R-WPT system have been proposed. Second, the radial-flux coupler has been designed and optimized. Third, the rotor state identification algorithm has been proposed. Fourth, the voltage and current variation of the primary side and the secondary side of the S--S compensation topology and LCC-S compensation topology have been studied separately, while the coupling degree of the coupler changes. A mutual inductance identification model has been proposed. Fifth, a prototype has been built and tested. From the experimental results, it is verified that the system can realize the power transmission of 13.5 W with a comprehensive efficiency of 74.1% and measure the rotor speed stably to determine its state at the same time.