Patent ID: 8829730
Filing Date: 2014-09-09
Classification: H02J,H04B

Abstract:
1. A wireless power feeder comprising: a power transmission side resonance unit that constitutes a part of a resonance circuit constituted by connecting a first capacitor, a second capacitor, a first coil, and a load and includes one of two electrodes constituting the first capacitor and one of two electrodes constituting the second capacitor; a first switch that controls supply of current to the power transmission side resonance unit in a first direction; a second switch that controls supply of current to the power transmission side resonance unit in a second direction; a power transmission control circuit that alternately turns the first and second switches conductive to make the first capacitor, second capacitor, and the first coil included in the resonance circuit resonate so as to allow the first and second capacitors to each feed AC power from the one electrode to the other electrode; a second coil that generates inductive current; and a phase detection circuit that detects a phase difference between voltage and current phases of the AC power, wherein a path of current flowing in the first and second switches and a path of current flowing in the transmission side resonance unit are separated by a coupling transformer, and AC current is supplied to the transmission side resonance unit via the coupling transformer, the second coil is wound around a core and generates the inductive current using a magnetic field which is generated when the AC current supplied to the transmission side resonance unit via the coupling transformer passes through the core, the phase detection circuit detects the current phase of the AC power based on the phase of the inductive current flowing in the second coil, the first and second capacitors are each constituted by opposite circular electrodes, one of the first and second capacitors is constituted by opposite disc-shaped electrodes, and the other capacitor is constituted by opposite annular-shaped electrodes.