Automated Alignment With Respect to a Moving Inductive Wireless Charger

Abstract

Wireless charging is an attractive technology that often promises increased mobility for electrical devices. However, commonly available wireless charging systems are generally intolerant to misalignment between the charger and the receiving device due to the need for inductive coupling between the two, defeating the promise of mobility. Many techniques have been studied to address this issue, including improved electrical circuits, novel charger coil designs, and the use of sensors for detecting misalignment. In this article, a new arrangement of sensing coils is used to detect lateral misalignment between a moving wireless charger and a mobile robot. Data from the sensing coils are used in a dual-loop control of the robot. The inner loop controls the robot velocities and consists of a linear quadratic regulator with integral action. The outer loop provides reference velocities to the inner loop based on the readings of the sensing coils. Using this method, an experimental mobile robot maintains alignment within 2 cm with respect to a 5-W wireless charger that moves up to 0.145 m/s. This automated alignment method is a low-cost solution that enables mobile systems, such as autonomous vehicles, to wirelessly charge while the charger is moving.