Misalignment effect on efficiency of wireless power transfer for electric vehicles

In order to consistently provide efficient EV wireless charging, changes in efficiency caused by coil misalignment should be investigated. This body of work uses a vector network analyzer to record the power transmission coefficients then calculate the efficiency and coupling factors. An automated 3-axis platform was built for coil motion control. The test result shows that the efficiency can remain at 90% as long as the misalignment ratio is within 0.5 and the air gap ratio is from 0 to 0.25.