A Wireless Charging Station for Multipurpose Electronic Systems

Abstract

This article discusses an experiment within wireless charging, a technology that has been available for more than a hundred years, namely, since the inception of the Tesla transformer; currently, one of the main application fields lies within small-size electronics to recharge electric vehicles (EV). Our concept of a wireless charging station (WCS) exploits the inductive power transmission (IPT) of electrical energy; the actual device principally consists of a dock and a charger. The experimental setup comprises a transmission coil operating at frequencies up to 108 kHz; a circular spiral coil on the receiving and transmitting sides; a rectifier with a step-down converter; and controllers. In terms of defining the main parameters, we compute the wireless power transfer (WPT) efficiency and simulate the magnetic field of the coils, using CST EM studio to execute the latter procedure. The behavior of the field is shown for different coil positions. As regards the functional processes, we can stress that the wireless modules communicate in the ISM band, employing GFSK modulation, and that they monitor the voltage and current in the charger, thus helping to detect improper positioning of the coils. Generally, the applied methodology and its practical embodiments may also facilitate accurate landing of unmanned aerial vehicles (UAV), substituting the landing scenario where a camera and quick response (QR) code detection are needed. Precise UAV guidance towards the station, however, requires the global position system (GPS). A minor problem emerges in relation to the energy transfer: an electromagnetic field (EMF) is generated between the coils, and this field has to be eliminated due to electromagnetic interference (EMI). Such a spurious effect may affect the guidance and information systems, possibly causing major errors in the electronics. The station is designed to recharge low voltage and low power devices, including those operating on separated extra low voltage (SELV).