Optimised Control Strategy for Transmission Efficiency of Wide Load Range WPT system

The wireless power transfer(WPT)system must operate across a wide power range to accommodate the varying demands of electric vehicle(EV)charging. However, conventional triple-phase-shift(TPS)control generates significant reactive power at light loads, resulting in reduced system efficiency. To overcome this limitation, a power regulation method based on different switching combinations is proposed. This paper first examines the control theory of TPS in a full-bridge topology. It then analyzes its application in a half-bridge topology and provides some theoretical comparison between two conditions. Based on this, various power range combinations are derived to achieve both load matching and soft switching, and a control strategy is further proposed to optimize system performance across a wide load range. Finally, an experimental platform was developed to validate the proposed method. Results demonstrate a 3% improvement in transmission efficiency at a power level of 300W (medium load) and a 9% improvement at 280W (light load).