Maximum efficiency point tracking by input control for a wireless power transfer system with a switching voltage regulator

In wireless power transfer (WPT) systems, changes in the receiver position and load resistance affect the output voltage and power efficiency. A receiver-side switching voltage regulator is useful for output voltage regulation, but it cannot be utilized with a DC-DC converter dedicated to conventional maximum efficiency point tracking (MEPT). As an MEPT method compatible with a switching voltage regulator and basically without feedback information, we propose MEPT by input control to make the switching voltage regulator undertake the role of the DC-DC converter of a conventional MEPT. To enable the proposed MEPT, we propose two additional essential technologies. One is a system design to remove the instability caused by a switching voltage regulator at the maximum efficiency point. The other is the activation timing of a switching voltage regulator to reach a stable point. Measurements using a 0-Ω power source and a K-inverter validate the proposed methods.