Resonant Inductive Wireless Charging System for Light Electric Vehicles

Abstract

Abstract newlineWireless power transfer (WPT) is being explored as a future solution to minimize the newlineinconvenience in charging the Electric Vehicles (EVs). Studies report that the main newlineobstacles in WPT especially for stationary charging of EVs are: Selection of coil geometry newlinehaving tolerance to misalignment and distance variation; suitable compensation newlinetopology for improving efficiency and maximizing power transfer capability; a proper newlineshielding for the coil system to minimize the strength of electromagnetic field (EMF) newlinesurrounding the vehicle as per safety standards; developing a suitable charging strategy newlinewhich can reduce the charging time anxiety without any compromise on the health of newlinethe batteries. newlineAt first, different types of coil geometries available in the literature are studied. It has newlinebeen found that the circular coils are appropriate for stationary charging of EVs as newlinethey are having similar misalignment tolerance in all the direction on the same plane newlineand are cost effective from fabrication point of view. To understand the nature of the newlineinductive parameters of the circular coils with variation in geometrical parameters, study newlineof parametric variations like number of turns, turn distance, coil gap distance has been newlinecarried out through finite element method approach. This study has been extended with newlinedifferent types of ferrite cores like E, C, I type. The out comes are compared to select newlinecoil structure for charging the EVs. It was found that circular spiral coils with I type newlineferrite core is the best suitable structure. newlineThe transmitting and receiving circular spiral coils can be symmetrical or asymmetrical newlinein shape. Asymmetrical circular spiral coils with unequal outer diameter exhibits newlinebetter tolerance to misalignment with the limitation of smaller averaged coupling coefficient. newlineTo investigate the dependency of mutual inductance and variation in coupling newlinecoefficient on the dimension of asymmetrical circular spiral coil, analytical equations newlineix newlinex newlineare developed. Then the analysis of the tolerance to the misalignme