Robust Communicationless Control Strategy to Synchronize In-Motion Secondary to the Primary

Dynamic wireless power transfer (DWPT) systems for electric vehicles can benefit significantly from the use of secondary active rectifiers by adding useful features such as bi-directional power flow, output power regulation, active control of the reflected impedance, and simplified vehicle detection. This has introduced the need for robust and reliable controls to mitigate some of the key dynamic challenges. A control scheme is proposed in this paper that uses zero crossing detection (ZCD) of free resonant current to synchronize the in motion secondary inverter to the primary inverter. The presented approach is capable to compensate for the detuning of the WPT system through rectifier impedance regulation which also results in efficiency optimization. A discrete time phase locked loop (PLL) synchronization controller comprising of a stabilizing PI compensator is designed and analyzed. The design is validated through simulations and experimental results from a 10 kW prototype system are presented.