A wireless battery charging system that varies the magnetic field frequency to maintain a desired voltage-current phase relationship

摘要

An electrical charging system (12) configured to wirelessly charge an energy storage device (14), such as a battery (14). The charging system 12 includes an off-transducer 18 in electrical communication with an alternating current power source 48 and electromagnetically coupled to an on-vehicle transducer 20 connected to the energy storage device 14 do. The controller 53 changes the frequency of the electric power sourced by adjusting the variable frequency oscillator 71 in the power transmitter 16. [ The charging system 12 includes a phase detection circuit 72 that is configured to communicate with the controller 53 and the off-transducer 18 and to determine the phase difference between the alternating current and the alternating current supplied by the power source 48 ). The controller 53 is configured to adjust the variable frequency oscillator 71 based on the phase difference so that the frequency of the sourced electric power maintains a phase difference within a desired range.