Wireless Power Transfer System for Mobile Robots via Magnetic Resonant Coupling with Automated Impedance Matching

Abstract

Wireless power transfer via magnetic resonant coupling can be used to supply power to a mobile robot within a few meters of a transmitter coil. However, when the robot moves or its power consumption fluctuates, its input impedance varies and causes power reflection. Therefore, we propose the use of multiple identical driver coils on the transmitter side in order to match the input impedance. The input impedance is matched and power reflection is eliminated by switching driver coils, i.e., regulating the coupling coefficient between the driver and the transmitter. During experiments, the transmitting efficiency showed good agreement with the calculated value, and the input impedance was well-matched under assumed range of varying distances and load resistances. Therefore, the proposed system was expected to solve the power reflection issues in mobile robots automatically.