Wireless Power Transfer Link Efficiency

This work is an initial attempt to investigate the potential utilization of wireless charging technology in the use case of an electrically powered wheelchair. The concept of the wireless power transfer is a well-known technique currently revived by the consumer electronics industry. The potential of technology is broadly discussed, even though there are few quantitative benchmarks characterizing the key parameters. The main drawback of the wireless charging has been proven to be the inductive link between the main and the pickup coils resulting into poor efficiency. After examining several existing analytical models for wireless power transfer a model is proposed, simulating the coupling factor in dependency on various misalignment cases. Correspondingly, a practical implementation of a low power wireless power transmitter is introduced providing experimental reference data for the model validation. This work was designed to investigate and to provide reliable benchmarks for power transfer efficiency. The evaluated results determine factors influencing the inductive link efficiency as well as provide comparison data between the wired and corded chargers in a 24-hours use case.