Abstract: According to one embodiment, there is provided a magnetic coupling device including a first coil, a second coil, a third coil, a fourth coil, a first constant-potential node and a second constant-potential node. The second coil is electrically connected with one end of the first coil and wound in a direction opposite to a direction in which the first coil is wound. The third coil faces the first coil. The fourth coil faces the second coil. The first constant-potential node is electrically connected with one end of the third coil. The second constant-potential node is electrically connected with one end of the fourth coil.

Abstract: A transformer includes a first coil disposed on a first surface, a second coil disposed on the first surface so as to surround the first coil, a third coil disposed on a second surface that is vertically adjacent to the first surface with an insulating layer, and a fourth coil disposed on the second surface so as to surround at least a part of the third coil, and when a current is caused to flow through the first coil, the first coil generates magnetic fluxes that pass through the first coil in opposite directions, and when the current is caused to flow through the first coil, the magnetic fluxes generated by the first coil pass through the first coil in opposite directions, and when a current is caused to flow through the second coil, the second coil generates magnetic fluxes that pass through the second coil in a single direction.

Abstract: According to one embodiment, a wireless power transmission system includes: a power transmission device and a power reception device. The power transmission device includes an AC power generation circuit; first circuits connected to the AC power generation circuit; and power transmission resonators. The power reception device includes: power reception resonators, second circuits each connected to different one of the plurality of power reception resonators and a rectifier circuit. An absolute value of an open-circuit output reverse voltage gain in an F matrix of each of the plurality of first circuits is less than 1, and an absolute value of a short-circuit output reverse current gain in an F matrix of each of the plurality of second circuits is less than 1.

Abstract: According to one embodiment, there is provided a power transmitting device including: a power supply, a resonator, an adjuster and a controller. The power supply supplies AC power. The resonator includes a magnetic core and a coil wound around the magnetic core, the resonator wirelessly transmitting the AC power supplied from the power supply to a different resonator arranged to be opposed to the resonator. The adjuster relatively moves the coil and the magnetic core along a longitudinal direction of the coil. The controller controls the adjuster based on a value of current flowing in the resonator to adjust relative positions of the magnetic core and the coil.

Abstract: A device of one aspect of the present invention includes a receiver to receive a modulation signal that has been subjected to frequency shift keying division ratio. The receiver includes a first demodulator and a demodulation control signal generator. The demodulation control signal generator includes a first frequency divider, a frequency control signal generator, and an oscillator. The first frequency divider divides a frequency of one of the modulation signal and the demodulation control signal by a first or second reception division ratio. The frequency control signal generator generates a frequency control signal based on a frequency of the other of the modulation signal and the demodulation control signal, and a frequency of the one of the modulation signal and the demodulation control signal obtained by division by the first or second reception division ratio. The oscillator generates the demodulation control signal based on the frequency control signal.

Abstract: According to one embodiment, a drive device drives “N” number (N is an integer of “2” or greater) of inverters to generate AC power and transmit respective AC power to transmission coil units corresponding thereto and includes a switching signal generation circuit. The switching signal generation circuit generates switching signals to drive first to fourth switching elements of each inverter to complementarily drive the first switching element and the second switching element, and complementarily drive the third switching element and the fourth switching element so that a phase difference between an output current of an “M”th (“M” is an integer of 2 or greater and “N” or below) inverter and an output current of an “M?1”th inverter becomes or approach “360×L/N” degrees (“L” is an integer of “1” or greater and less than “N”) and supplies the switching signals to the first to fourth switching elements of the inverters.

Abstract: According to one embodiment, a wireless power transmission system includes: a power transmission device and a power reception device. The power transmission device includes an AC power generation circuit; first circuits connected to the AC power generation circuit; and power transmission resonators. The power reception device includes: power reception resonators, second circuits each connected to different one of the plurality of power reception resonators and a rectifier circuit. An absolute value of an open-circuit output reverse voltage gain in an F matrix of each of the plurality of first circuits is less than 1, and an absolute value of a short-circuit output reverse current gain in an F matrix of each of the plurality of second circuits is less than 1.

Abstract: According to one embodiment; a wireless power transmission system includes; an AC power source; a power transmission resonator; a power reception resonator; an AC/DC converter; a first circuit disposed between the AC power source and the power transmission resonator; and a second circuit disposed between the power reception resonator and the AC/DC converter. Parameter values of passive elements in the first and second circuits are set so that an absolute value of an inverse transfer function between an input voltage and an output voltage of a target system at a frequency of the AC voltage is equal to or less than a divided value of the AC voltage by a battery voltage while the AC voltage is increased from a first voltage value to a second voltage value, the target system comprising the first circuit, the power transmission resonator; the power reception resonator, the second circuit and the AC/DC converter.

Abstract: According to one embodiment, a voltage converting device includes a DC power source; an inverter generating AC power; an AC component detector configured to detect an AC component of current flowing through a first terminal or a second terminal of the inverter in the DC power source side; and a phase estimator configured to estimate a phase relation between a phase of voltage of the AC power and a phase of current of the AC power based on an amplitude of a specific frequency component contained in a first absolute value signal of the AC component. The AC power generated by the inverter is supplied to a loading device, and an impedance of the loading device at a fundamental of a driving frequency of the inverter is smaller than an impedance of the loading device at an odd-order harmonic of the driving frequency.

Abstract: A power transmitting apparatus including a power supply to generate AC power; a power transmitting inductor to transfer the AC power to a power receiving apparatus through magnetic coupling with a power receiving inductor in the power receiving apparatus; a mutual coupling adjusting unit to adjust a relative position between the power transmitting inductor and the power receiving inductor; and a control unit to control the mutual coupling adjusting unit based on a mutual coupling coefficient between the power transmitting inductor and the power receiving inductor. The control unit controls the mutual coupling adjusting unit so that the mutual coupling coefficient falls within a predetermined range and an upper limit of the predetermined range is a value less than a maximum of the mutual coupling coefficient between the power transmitting inductor and the power receiving inductor.

Abstract: A receiving apparatus includes a variable gain unit to change between a first gain and a smaller second gain, and to amplify a received signal to obtain an amplified signal; a comparator to compare a power of the amplified signal with a reference value; and a controller to set a gain to the first gain while in a standby state, to reset a gain to a third gain between the first and second gains if in a standby state the power of the received signal is larger than the reference value, and then to set a gain to the first gain and return to the standby state if the power is equal to or lower than the reference value, or if not, to a fourth gain between the first and third gains.

Abstract: There is provided a power transmitting apparatus including: a power supply, a power transmitting inductor, a mutual coupling adjusting unit and a control unit, in which the power supply supplies AC power, the power transmitting inductor transfers the AC power to a power receiving apparatus through magnetic coupling with a power receiving inductor in the power receiving apparatus, the mutual coupling adjusting unit adjusts a relative position between the power transmitting inductor and the power receiving inductor, and the control unit controls the mutual coupling adjusting unit, based on a mutual coupling coefficient between the power transmitting inductor and the power receiving inductor.

Abstract: According to one embodiment, a drive device drives “N” number (N is an integer of “2” or greater) of inverters to generate AC power and transmit respective AC power to transmission coil units corresponding thereto and includes a switching signal generation circuit. The switching signal generation circuit generates switching signals to drive first to fourth switching elements of each inverter to complementarily drive the first switching element and the second switching element, and complementarily drive the third switching element and the fourth switching element so that a phase difference between an output current of an “M”th (“M” is an integer of 2 or greater and “N” or below) inverter and an output current of an “M?1”th inverter becomes or approach “360×L/N” degrees (“L” is an integer of “1” or greater and less than “N”) and supplies the switching signals to the first to fourth switching elements of the inverters.

Abstract: A method of attaching a ring gear to a differential case includes: a first step for fitting the ring gear onto an outer peripheral side of the differential case; and a second step for outwardly deforming a caulk-fixed part of the differential case to prevent the ring gear from being dropped out from the differential case. In the second step, a jig having an inclined surface that can contact an inner peripheral surface of the caulk-fixed part of the differential case is pushed along a rotational axis direction of the differential case to outwardly deform the caulk-fixed part. The inclined surface of the jig and the inner peripheral surface of the caulk-fixed part are subjected to a surface treatment to increase a friction.

Abstract: There provided a power receiving device connectable with a first load circuit operating according to AC power from a power transmitting device in which the power receiver receives the AC power from the power transmitting device via magnetic coupling, the impedance adjuster is capable of converting at least one of voltage and current of the AC power received at the power receiver, the controller controls increase in output voltage of the power transmitting device, the AC power is supplied to the first load circuit via the impedance adjuster when the first load circuit is connected to the power receiving device, and the controller controls the impedance adjuster such that an input impedance of the impedance adjuster is lower than an input impedance of the first load circuit during at least a part of a time period where the output voltage of the power transmitting device is increased.

Abstract: According to one embodiment, there is provided a power transmitting device including: a power supply, a resonator, an adjuster and a controller. The power supply supplies AC power. The resonator includes a magnetic core and a coil wound around the magnetic core, the resonator wirelessly transmitting the AC power supplied from the power supply to a different resonator arranged to be opposed to the resonator. The adjuster relatively moves the coil and the magnetic core along a longitudinal direction of the coil. The controller controls the adjuster based on a value of current flowing in the resonator to adjust relative positions of the magnetic core and the coil.

Abstract: A foreign object detection device has a foreign object detector configured to detect a foreign object when a power receiver receives power from a power transmitter in a non-contact manner, the foreign object detector being arranged between the power receiver and the power transmitter, and a power control signal generator configured to generate a power control signal which controls the power transmitted from the power transmitter when the foreign object is detected by the foreign object detector

Abstract: According to one embodiment, there is provided a control apparatus for a first wireless power transmission apparatus and a second wireless power transmission apparatus. The first wireless power transmission apparatus includes a first inductor and an alternating-current signal source that supplies an alternating-current power to the first inductor. The second wireless power transmission apparatus includes a second inductor that receives the alternating-current power wirelessly from the first inductor. The position controller controls a phase relationship of current flowing in the first inductor and the second inductor such that attractive force or repulsive force is generated between the first and second inductors, and adjusts a relative position of the first inductor and the second inductor by use of the attractive force or the repulsive force.