MODELLING AND COMPARATIVE ANALYSIS OF INDUCTIVELY COUPLED CIRCULAR AND SQUARE LOOP WIRELESS POWER TRANSFER AT UHF BAND FOR AUTOMOBILE CHARGING

Abstract

Electric cars are now in high demand in every part of the world in order to minimise fossil fuel usage, which in turn will reduce environmental pollution with a view to achieving a green environment. Wireless Power Transmission (WPT) is now becoming a technology that is highly sought globally. Wireless Power Transmission is an approved and achieving technology, uncovering its applications in various fields. Power is transferred from a source to an electrical load without the need for interconnection. In this research, inductively square and circular loop wireless power transfer was simulated, modelled and analysed for charging cars (Electric Vehicles). The effects of orientation and alignment, as well as coupling losses, of transmitting and receiving loops were observed. Square and circular loop sizes and orientation were determined. Simulation was accomplished using the electromagnetic system COMSOL Multiphysics 5.5 at a frequency domain of 1.8MHz. Results obtained from the simulation showed a strong coupling at 0 degrees and a heat coupling around the receiving antenna at an angle of 90 degrees for the square loop, while the circular loop displayed perfect coupling at all angles, with average electromagnetic wave energy/power flow for both circular and square ranges from 3.4433 to 12.308Wm2 and directivity of 6.7502 and 1.3018dB, respectively, which makes the circular loop more acceptable for electrical vehicle charging. The radiating coupling power at different varying angles depends on their reflection coefficient (S-parameters), which explain how much power is reflected and how the variation in the position and orientation of the loops affects the mutual coupling. These results indicate that a square loop is good for direct charging while a circular loop is absolutely perfect for both direct and indirect charging.