Research on Coil Switching Strategy Based on the Multi-Transmitter WPT System

This paper presents a coil positioning method by introducing auxiliary windings based on the multi-transmitter wireless power transfer (WPT) system. The switching of the transmitter coil reduces the variation range of the coupling coefficient, and the detuning design of the compensation network reduces the output voltage fluctuation. The position of the receiving coil is determined by the induced voltage of the auxiliary winding and the current variations of transmitting coils. The single-stage scheme based on primary-side control can improve transfer efficiency and reduce the size of the receiver. Finally, experimental validation is performed using a 100 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathrm{W} / 20 \mathrm{V}$</tex> prototype, achieving a peak efficiency of 93.32%, with the output voltage regulation remaining within 3.5%. The power density of the receiver is <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$6.68 \mathrm{W} / \text{cm}^{3}$</tex>, with a height of 8.45 mm.