Coil Current Synchronization Control Method for EV-DWPT System

In the switching state of the electric vehicle dynamic wireless power transfer (EV-DWPT) system with a short-individual structure, adjacent power units will supply power to the vehicle pickup side simultaneously. The phase difference between adjacent coil currents will reduce the total value and change the phase of the synthesized induced voltage on the pickup side, adding burden to the pickup side control. Providing a driving signal to all power units from DC source information bus can reduce the phase difference of adjacent coil currents. However, inevitable system parameter drift with changes in mutual inductance will make phase difference changes more severe. Therefore, this article proposes a coil current synchronization method that detects the phase difference between the coil current and the bus drive signal in real time, adjust the driving signal of a single power unit, and keeps the phase difference between the coil current and the bus signal drive at the expected value. A simulation model was built to simulate the mutual inductance and phase changes of the EV during normal driving, and the driving signal was controlled through a PI controller to control the coil phase. The simulation results show that this method can achieve synchronization of the current phases of each coil under parameter drift and mutual inductance changes.