A Robust Wireless Power Transfer System With Self-Alignment Capability and Controllable Output Current for Automatic-Guided Vehicles

In this article, a robust wireless power transfer system is proposed with self-alignment capability and controllable output current characteristics for static charging of automatic-guided vehicles (AGVs). A reconfigurable circuitry is designed to work initially in an inductor–capacitor–capacitor-series compensation mode for achieving magnetic field self-alignment, then switched to the LCC – LCC configuration for wireless charging. Apart from the passive components used for wireless power transfer, no additional components, such as cameras, sensors, or dedicated sensing coils, are needed for self-alignment. The induced voltage of a series-tuned Q-coil on the load side is used for the AGV to automatically adjust its position. The vehicle will be self-aligned when the induced voltage becomes null, then the system is switched to a controllable constant current charging mode. A prototype is built, which demonstrates that the output charging current is controllable and can be kept constant against load variations. The experimental results show the proposed system can realize an 89.1% dc–dc power transfer efficiency at an output current of 30 A and an output voltage of 48 V.