Abstract: A power supply system includes: a power transmission circuit provided on the ground side; a high frequency generation circuit that supplies high-frequency electric power to the power transmission circuit; a measurement unit that measures a physical quantity corresponding to the degree of coupling between the power transmission circuit and a power reception circuit provided in a vehicle; and a control unit. When the degree of coupling is determined, based on the measured physical quantity, to be lower than a predetermined degree, the control unit sets the impedance of the power transmission circuit to a first impedance and thereby sets the power transmission circuit to a non-resonant state. In contrast, when the degree of coupling is determined to be not lower than the predetermined degree, the control unit sets the impedance of the power transmission circuit to a second impedance and thereby sets the power transmission circuit to a resonant state.

Abstract: A coil assembly for wireless electrical power transmission includes a plurality of external connecting terminals, a power feeding coil, a resonant capacitor electrically connecting with the power feeding coil, and busbars each of which electrically connects between the external connecting terminals.

Abstract: A primary-side resonant circuit of a power transmission apparatus has an impedance varying element that increases, when supply of electric power is stopped, an input impedance of the primary-side resonant circuit so as to have predetermined standby current flowing through a primary-side coil. A power reception apparatus includes a magnetic flux amplifier circuit configured to amplify magnetic flux generated by the standby current flowing through the primary-side coil of the primary-side resonant circuit. The power transmission apparatus further includes a primary-side detection circuit configured to detect a change in the voltage of the primary-side coil, a change in electric current flowing through the primary-side coil or a change in a magnetic field in the vicinity of the primary-side coil; each of the changes is caused by the magnetic flux amplified by the magnetic flux amplifier circuit.

Abstract: A wireless power transmission system is provided which wirelessly transfer electric power from a power transmitter to a power receiver. The wireless power transmission system works to set a capacitance of a primary capacitor of a primary resonant circuit to undergo resonance with a self-inductance of a primary coil at an angular frequency that is an operating frequency. A tertiary capacitor of a tertiary resonant circuit has a capacitance set to undergo resonance with a self-inductance of a tertiary coil. A secondary capacitor of a secondary resonant circuit has a capacitance set to reduce a reactive component of ac power arising from self-inductances and mutual inductances of the primary coil, the secondary coil, and the tertiary coil.

Abstract: A dynamic wireless power transfer system performs, through a plurality of primary coils installed along a traveling direction of a road and a secondary coil mounted in a vehicle, power transfer to the vehicle while the vehicle is traveling. The secondary coil is an M-phase coil including M coils, M denoting an integer which is two or higher. The M coils each include a coil end extending along a front-rear direction of the vehicle and a main coil portion extending along a width direction of the vehicle, the M coils each being configured such that a magnetic resistance of a magnetic path where a magnetic flux of the coil end passes is higher than a magnetic resistance of a magnetic path where a magnetic flux of the main coil portion passes.

Abstract: A contactless power supply system is provided for supplying electric power to a vehicle in a contactless manner during traveling of the vehicle. The contactless power supply system includes a plurality of primary coils installed along a traveling direction in a road and a secondary coil mounted to the vehicle. Each of the primary coils is a single-phase coil with the secondary coil being a multi-phase coil, or is a multi-phase coil with the secondary coil being a single-phase coil.