Power Factor Improvement Control of Variable Active Capacitor System for Wireless Power Transfer

The wireless power transfer (WPT) is one of the charging methods for EVs, and research is underway to popularize it due to its high level of convenience. A problem with WPT is that the power transmission efficiency fluctuates depending on the positional relationship between the power transmission coils. An active capacitor system (ACS) that functions as a capacitor with virtually any capacitance through inverter control have been proposed. In this paper, an automatic control method for input power factor improvement by the ACS is proposed. The system operation and control method are presented and the proposed system is implemented through simulation and experiment to demonstrate its effectiveness.