Measurement and Calculation Method of Wireless Power Transfer Coil Equivalent Series Resistance under the Vehicle

In order to design a highly efficient wireless power transfer (WPT) for plug-in hybrid vehicles (PHVs), a novel methodology is proposed to measure the efficiency of power transfer between transmitting and receiving coils and to calculate the equivalent series resistance (ESR) of coils under actual vehicle mounting. The proposed measurement method can accurately measure the ESR of coils at the rated current that cannot be measured by low-current general-purpose instruments such as LCR meters. The proposed calculation method can accurately calculate the ESR of WPT coils under the vehicle such as the steel body and the muffler. Experimental results under the vehicle verify the accuracy of their proposed methods.