Coil Parameter Analysis in Wireless Electric Vehicle Charging

The hassle of using plug-in charging for electric vehicles (EVs) such as connecting charger to the port of vehicles, risk of getting electrocuted during rain, dirty and oily charging cable etc. can be eliminated using wireless/induction power transfer (IPT). It can be made smart and automated. Hence, IPT can be considered the future of EV charging. However, the technology is just emerging and there are a lot of limitations at present. The major problems are less efficiency caused by coil misalignment and air gap, and the electro-magnetic field generated around the coils which possesses greater risk for human health. These can be improved by selecting the types of coils and shields which produce maximum magnetic flux between the coils whereas reduce the flux outside the coils. In this research, the strength of magnetic fields produced by various types of coils (circular, square and hexagonal) were simulated in Ansys Maxwell 3D to understand their features and to know which coil is the best for high power transfer efficiency. Similarly, the effects of using ferrite and aluminum shields for leakage reduction, by varying their thickness, were studied. Finally, the leakage flux values were simulated at very high currents to understand their behavior in such conditions.