Microcontroller assisted wireless energy transmission

Abstract

The design and implementation of a way to transmit electromagnetic energy using electromagnetic waves is presented in this paper. Preliminary studies were conducted at low frequency and proved the fact that low frequency alternative electrical energy can be transmitted by using magnetically coupled coils that are placed at a close distance to each other, with high energy efficiency when the alignment, parallelism, and the gap between coils is set properly. Simulation and theoretical studies regarding the physical quantity involved in energy transfer, were conducted. The experiments were conducted using laboratory equipment, microwave generating circuits and directional antennas. Experimental data obtained are presented in graphs, while considering magnetic field. Because this subject is very important for wireless charging and the distance considered during the experiments is in the order of tens of centimetres, we propose the development of our idea for industrial applications. In the end, this paper proposes an optimisation model for wireless energy transmission between two devices, considering the case where the coupling is not constant between the two coils that form the transformer, by tuning the impedance of the electronic circuit from the secondary coil. The hypothesis for optimising the efficiency of the energy transfer in open transformers with variable coupling factor is verified in this paper using several simulations performed in LTSpice. The simulations show that the mutual inductance of some coils, which influences the efficiency of electromagnetic transmission, and the impedance and frequency characteristics of the secondary circuit are closely related. The entire optimisation process is performed using a PID regulator using an eight-bit microcontroller.