Energy Efficiency in Inductive Wireless Charging Systems for Electric Vehicles

With the massive appearance of electric vehicles (EVs) around the globe, the demand for more handy ways of charging is increasing sharply, and wireless charging turns out to be one of the most promising solutions. However, the low energy efficiency is one of its crucial limits that impedes its massive application. This passage justifies the significance of improving the energy efficiency of inductive wireless power transfer (IWPT), and then summarize the factors which affect the energy efficiency and ways of improvement through analysis of past literature, reasoning and calculation. It is found that the main influencing factors of energy efficiency include the relative location of coils, the frequency of alternating current which is sent into the primary coil, the design of coils, and the degree of matching between system load and the impedance of secondary coil. Possible ways to improve energy efficiency include decreasing the difference in positions through the use of an automatic device, using alternating current with the appropriate frequency, modifying the design of primary coil, choosing the proper coil, matching of impedance, compensation, using an array of coils, and using a static charging system.