Patent ID: 10998772

Abstract:
An electric power transmitting device includes a radio frequency power circuit that converts a direct current power supply to radio frequency electric power having a switching frequency, a transmitting coil connected to the radio frequency power circuit and magnetically coupled to a receiving coil in an electric power receiving device, and a transmitting resonance capacitor that is connected to the transmitting coil and that forms a resonant circuit together with the transmitting coil. The transmitting coil has flexibility to allow a coil opening to be closed, and capacitance of the transmitting resonance capacitor is determined so that while the transmitting coil is opened, resonance of the resonant circuit occurs at a resonant frequency, which matches the switching frequency, and while the transmitting coil is substantially closed, the resonance of the resonant circuit does not occur at the switching frequency, which deviates from a resonant frequency of the resonant circuit.