Wireless Fleet Charging System for Electric Bicycles

This paper proposes a double-coupled inductive system for multi-pickup systems, which is intended for wireless charging of a fleet of electric bicycles. An intermediary coupler is introduced between the primary and pickup where it operates as a switch. The intermediary coupler turns ON when the bicycle is present and turns OFF when the bicycle is absent to prevent magnetic fields from radiating into the environment. The switching method for the proposed intermediary coupler configuration provides quick turn ON and OFF without significant transient spikes. Sensitivity analysis of the proposed system was undertaken to analyze the reflected impedance at the primary due to variations in the tuning components. A practical system that is capable of producing up to 400 W at its output has been built. The proposed intermediary coupler and pickup has achieved an efficiency of 86% at 400-W output. The overall system efficiency including the power supply was 76%. With more branches of intermediary couplers and pickups drawing power from the primary power, the standing losses in the system are shared and the system efficiency improves.