Effects of multiple loads in a contactless, inductively coupled linear power transfer system

This paper describes an approach for a contactless, inductively coupled resonant energy supply system for multiple, independent endpoints. Typical contactless inductive energy supplies in industrial applications involve a combination of one primary inverter/coil and one secondary coil with a rectifier and a load. The work presented in this paper issues a one-to-many-approach instead, which can be used for creating a contactless automation network, having multiple secondary side loads driven by only one primary coil. The challenge is to run such a system in resonance, as every participant potentially affects the resonant frequency, and therefore the overall system efficiency. The effects of multiple participants on the resonant frequency are modeled, and the theoretical examinations are backed up by measurements run on a rail-based test system.