An electromagnetically-coupled state detection circuit including a detection unit that measures a primary side Q value of a circuit containing a primary side coil electromagnetically coupled with a secondary side coil and power transmission efficiency to the secondary side coil, corrects the power transmission efficiency based on the Q value of the primary side coil, and detects a state of electromagnetic coupling with the secondary side coil based on an obtained corrected value of the power transmission efficiency.

A power transfer unit configured to transfer power using magnetic fields, and a foreign object remover configured to remove a foreign object in the vicinity of a power transfer path when the power is transferred.

A power supply device of the present invention includes a power transmission unit (15) configured to wirelessly supply power to the power receiving unit (9). The power transmission unit (15) includes: a ground-side coil (13); and a housing (21) set on a ground (19) and configured to house the ground-side coil (13). The housing (21) includes: a coil section (25) in which to dispose the ground-side coil (13); and a first projection (29) disposed closer to a vehicle entry side than the ground-side coil (13) is, and projecting upward from a surface of the coil section (25).

The present disclosure described herein relates to wireless power transfer systems and methods that efficiently and safely transfer power to electronic devices. In an aspect of the disclosure, a method for wirelessly transmitting power is provided. The method includes during a first time period, transmitting power at a first power level from a wireless power transmitter to the wireless power receiver. The method further includes determining a frequency for transmitting power at a second power level based on a ratio of a current level of the wireless power receiver to a current level of a wireless power transmitter at the first power level. The method further includes during a second time period, transmitting power at the second power level and at the frequency, the first power level lower than the second power level.

A wireless power-supplying system of the present invention includes a ground-based power-supplying device having a power-supplying coil and a vehicle having a power-receiving coil, and performs power supply from the power-supplying coil to the power-receiving coil in a wireless power supply manner. Further, this wireless power-supplying system includes a foreign matter intrusion prevention unit formed of a flexible material transparent to a magnetic field and having flexibility, and provided on the power-supplying coil to fill a space between the power-supplying coil and the power-receiving coil.

According to an embodiment of present invention, a wireless power transmitter for a vehicle that transfers power to a wireless power comprising: a resonance circuit comprising a coil assembly and/or a capacitor, wherein the coil assembly comprises first and second bottom coils placed adjacent to each other in a line and each consisting of a single layer of 11 turns and a top coil stacked on the first and second bottom coils and consisting of a single layer of 12 turns; a frequency full bridge driver driving each of coils included in the coil assembly individually, and a placement detection unit detecting a placement of the wireless power receiver.

A wireless electric vehicle charging system comprises base-side equipment for generating a magnetic field and vehicle-side equipment for receiving energy via the magnetic field to supply power to a vehicle-driving battery. Monitoring circuitry monitors one or more of voltage, current, or phase associated with the base-side equipment and halts generation of the magnetic field in response to a change in the voltage, current, or phase associated with the operation of the base-side equipment that indicates a fault condition at the vehicle-side equipment, which may include a loss of power or disconnection of a battery. Based on detection of the change, the monitoring circuitry can halt generation of the magnetic field to prevent damage at the vehicle-side equipment.

A wireless electric vehicle charging system comprises base-side equipment for generating a magnetic field and vehicle-side equipment for receiving energy via the magnetic field to supply power to a vehicle-driving battery. Monitoring circuitry monitors one or more of voltage, current, or phase associated with the base-side equipment and halts generation of the magnetic field in response to a change in the voltage, current, or phase associated with the operation of the base-side equipment that indicates a fault condition at the vehicle-side equipment, which may include a loss of power or disconnection of a battery. Based on detection of the change, the monitoring circuitry can halt generation of the magnetic field to prevent damage at the vehicle-side equipment.

A power reception device includes a first case having an accommodation portion formed therein, a core disposed in the first case, a second coil disposed in the first case and provided on the core, a first electrical device disposed in the first case and connected to the second coil, a first insulation member disposed between an inner surface of the first case and the second coil, and between the inner surface of the first case and the first electrical device, and a cooling device that causes a flow of a coolant to cool the second coil and the first electrical device, the second coil and the first electrical device being attached to the inner surface of the first case with the first insulation member interposed therebetween, the first electrical device being disposed upstream in a flow direction of the coolant from the second coil.

A coil unit provided on a ground side, including a coil, at least one sensor for detecting an object existing above or around the coil unit, a housing for accommodating the coil and the at least one sensor, wherein, the housing is provided with a dividing plate and at least one pillar for maintaining the internal space of the space for sensor, the dividing plate divides the space into a space for coil and a space for sensor located vertically above the space for coil, the space for coil is for accommodating the coil and the space for sensor is for accommodating the at least one sensor, and the at least one sensor is disposed on the dividing plate without contacting with an upper inner surface portion of the housing in the space for sensor.