Transferring Driving Pulses to Implement Dual-Side Phase-Shift Control of Wireless Power Transfer on Primary Side Using Driving Windings

Abstract

Although wireless power transfer (WPT) technology has many advantages, this wireless feature also brings issues. To regulate the output or to achieve synchronous rectification, the rectifier on the secondary side needs to be controlled. Also, for bidirectional power control, the phase difference between the ac voltages on the primary and secondary sides should also be regulated. The control of the rectifier on the secondary side requires phase synchronization with the primary side. Current solutions use the secondary current for frequency locking and phase synchronization. However, this method is dependent on the secondary current waveform, which can be discontinuous or distorted. Such waveforms can lead to issues. This paper proposes a dual-side phase-shift control using driving windings to transfer driving pulses without a secondary-side controller. The driving windings are decoupled from the power windings. By controlling the phase difference between the power and driving windings on the primary side, the phase difference between the power windings on both sides can be regulated, independent from power transfer. Circuit simulations in LTspice validate the effectiveness of the proposed method.