Abstract: A foreign matter detection device includes: a plurality of detection coils (43-1 to 43-n) between a transmission coil (12) of a power transmission device (2) and a reception coil (21) of a power reception device (3), through which power is transmitted in a contactless manner; a plurality of capacitors (44-1 to 44-n) forming, for each of the detection coils, a resonance circuit together with the detection coil; a power supply circuit (41) supplying AC power having a predetermined frequency to each detection coil; and a detection circuit (45) detecting a voltage output from each detection coil and detecting a foreign matter entering between the transmission coil (12) and the reception coil (21) according to the voltage detected. Then, each detection coil is arranged to overlap by a predetermined amount that allows electromagnetic coupling between adjacent two of the detection coils (43-1 to 43-n) to be ignored.

Abstract: A control circuit controls a power supply circuit to generate transmitting power having a frequency varying within a frequency range. The control circuit determines a stably transmitting frequency based on a detected output voltage of a power receiver apparatus, the stably transmitting frequency indicating a frequency of the transmitting power at which dependency of the output voltage on a load value of the power receiver apparatus is at least locally minimized within the frequency range. The control circuit determines a transmitting voltage based on the detected output voltage, the transmitting voltage indicating a voltage of the transmitting power at which the output voltage reaches a target voltage when generating transmitting power having the stably transmitting frequency. The control circuit controls the power supply circuit to generate transmitting power having the stably transmitting frequency and the transmitting voltage.

Abstract: A drive control apparatus is configured to drive and control a composite resonance circuit including LC resonant circuits including inductances L of power transmitting and receiving coils electromagnetically coupled to each other. The drive control apparatus includes: an inverter circuit configured to drive the composite resonance circuit by converting input DC power into AC power by switching the DC power at a predetermined operating frequency; an input current detector configured to detect an input current of the inverter circuit; and a frequency controller and driver configured to generate a drive signal of the inverter circuit while changing the operating frequency by using a predetermined extreme value search method to drive the inverter circuit, search for a resonance frequency of the composite resonance circuit based on the detected input current, and set the operating frequency based on the searched resonance frequency.

Abstract: A power transmitting apparatus included in a contactless power feeding apparatus includes a power supply circuit that supplies AC power having a predetermined drive frequency to a transmission coil for supplying power to a power receiving apparatus, a power receiving circuit that receives returning power transmitted from the power receiving apparatus, a control circuit that controls, according to a voltage of the returning power, the power supply circuit such that an output voltage of the power receiving apparatus is in a predetermined allowable range. Also, the power receiving apparatus includes a resonant circuit for receiving power via the transmission coil of the power transmitting apparatus, a rectifier circuit that rectifies power received via the resonant circuit, and a power transmitting circuit that transmits the returning power according to a voltage of power output from the rectifier circuit to the power transmitting apparatus.

Abstract: Provided is a resonance-type power conversion circuit and the like greatly reducing computation cost with a simple configuration. The resonance-type power conversion circuit according to the present invention comprises: a resonance circuit which includes a first LC resonance circuit and a switching element and which outputs an output voltage or an output current to a load; a detection circuit which detects output information being the output voltage or the output current: a computation control unit which searches, on the basis of the detected output information, for a local maximum point in a characteristic of the output information with respect to an operating frequency and which determines the operating frequency corresponding to the searched local maximum point; and a signal generation unit which generates a drive control signal having the determined operating frequency and which applies frequency control to the switching element on the basis of the drive control signal.

Abstract: A power reception device 3 includes: an estimation circuit 28 estimating a load resistance of an entire contactless power feed apparatus 1; and a reception-side communicator 27 transmitting an estimated value of the load resistance of the entire contactless power feed apparatus 1 to a power transmission device 2. The power transmission device 2 has a power supply circuit 11 supplying AC power to a transmission coil 12 supplying power to the power reception device 3. The power transmission device 2 further includes a control circuit 18 decreasing an input/output gain of a transmission-side DC-DC converter 31 included in the power supply circuit 11 by a predetermined amount when the estimated value of the load resistance is less than a predetermined allowed lower limit, and maintaining or increasing the input/output gain when the estimated value of the load resistance is equal to or greater than the predetermined allowed lower limit.

Abstract: A winding of a transmission coil included in a power transmission device of a contactless power feed apparatus and serving to transmit AC power to a power reception device contactlessly is formed of a wiring pattern provided on a substrate. The transmission coil is divided into partial coils arranged coaxially. Each of the partial coils is formed such that, among the partial coils, a number of turns of a winding included in a partial coil is larger as the partial coil is located more outwardly.

Abstract: A contactless power feed apparatus 1 has a relay circuit 4 relaying power transmitted from a power transmission device 2 to a power reception device 3 in a contactless manner. The power transmission device 2 has: a transmission coil 12 transmitting AC power to the relay circuit 4. The relay circuit 4 has: a first coil 31, electromagnetically coupled with the transmission coil 12 and receiving the AC power from the transmission coil 12; a second coil 32, transmitting the AC power to the power reception device 3; and a resonant capacitor 33, resonating with the AC power supplied to the transmission coil 12 together with the first and second coils 31, 32. The power reception device 3 has: a resonant circuit 20, having a reception coil 21 receiving AC power from the second coil 32 by being electromagnetically coupled with the second coil 32 of the relay circuit 4.

Abstract: A foreign matter detection device includes: a plurality of detection coils (43-1 to 43-n) between a transmission coil (12) of a power transmission device (2) and a reception coil (21) of a power reception device (3), through which power is transmitted in a contactless manner; a plurality of capacitors (44-1 to 44-n) forming, for each of the detection coils, a resonance circuit together with the detection coil; a power supply circuit (41) supplying AC power having a predetermined frequency to each detection coil; and a detection circuit (45) detecting a voltage output from each detection coil and detecting a foreign matter entering between the transmission coil (12) and the reception coil (21) according to the voltage detected. Then, each detection coil is arranged to overlap by a predetermined amount that allows electromagnetic coupling between adjacent two of the detection coils (43-1 to 43-n) to be ignored.

Abstract: A contactless power feed apparatus 1 has a relay circuit 4 relaying power transmitted from a power transmission device 2 to a power reception device 3 in a contactless manner. The power transmission device 2 has: a transmission coil 12 transmitting AC power to the relay circuit 4. The relay circuit 4 has: a first coil 31, electromagnetically coupled with the transmission coil 12 and receiving the AC power from the transmission coil 12; a second coil 32, transmitting the AC power to the power reception device 3; and a resonant capacitor 33, resonating with the AC power supplied to the transmission coil 12 together with the first and second coils 31, 32. The power reception device 3 has: a resonant circuit 20, having a reception coil 21 receiving AC power from the second coil 32 by being electromagnetically coupled with the second coil 32 of the relay circuit 4.

Abstract: A power reception device 3 includes: an estimation circuit 28 estimating a load resistance of an entire contactless power feed apparatus 1; and a reception-side communicator 27 transmitting an estimated value of the load resistance of the entire contactless power feed apparatus 1 to a power transmission device 2. The power transmission device 2 has a power supply circuit 11 supplying AC power to a transmission coil 12 supplying power to the power reception device 3. The power transmission device 2 further includes a control circuit 18 decreasing an input/output gain of a transmission-side DC-DC converter 31 included in the power supply circuit 11 by a predetermined amount when the estimated value of the load resistance is less than a predetermined allowed lower limit, and maintaining or increasing the input/output gain when the estimated value of the load resistance is equal to or greater than the predetermined allowed lower limit.

Abstract: A winding of a transmission coil included in a power transmission device of a contactless power feed apparatus and serving to transmit AC power to a power reception device contactlessly is formed of a wiring pattern provided on a substrate. The transmission coil is divided into partial coils arranged coaxially. Each of the partial coils is formed such that, among the partial coils, a number of turns of a winding included in a partial coil is larger as the partial coil is located more outwardly.

Abstract: In an insulated resonance circuit device, a first resonance circuit includes first and second LC resonance circuits electromagnetically coupled to each other and electrically insulated from each other, oscillates at a predetermined first resonance frequency based on an input AC voltage, and outputs an oscillation signal voltage. The second resonance circuit having a second resonance frequency substantially identical to the first resonance frequency resonates with the oscillation signal voltage to detect the oscillation signal voltage, and outputs the detected oscillation signal voltage. A control circuit compare the oscillation signal voltage from the second resonance circuit with a comparison signal voltage for obtaining a predetermined target output voltage and/or a predetermined target output current to generate and output gate signals for controlling a rectifier circuit.

Abstract: A power transmitting apparatus included in a contactless power feeding apparatus includes a power supply circuit that supplies AC power having a predetermined drive frequency to a transmission coil for supplying power to a power receiving apparatus, a power receiving circuit that receives returning power transmitted from the power receiving apparatus, a control circuit that controls, according to a voltage of the returning power, the power supply circuit such that an output voltage of the power receiving apparatus is in a predetermined allowable range. Also, the power receiving apparatus includes a resonant circuit for receiving power via the transmission coil of the power transmitting apparatus, a rectifier circuit that rectifies power received via the resonant circuit, and a power transmitting circuit that transmits the returning power according to a voltage of power output from the rectifier circuit to the power transmitting apparatus.

Abstract: A detection circuit detects at least one of a value of a current flowing through a power transmitting coil, and a value of a current or voltage generated by an auxiliary coil. A control circuit determines a transmitting frequency based on the value detected by the detection circuit, the transmitting frequency at least locally minimizing load dependence. The control circuit determines a voltage for the transmitting power at which an output voltage of a power receiver apparatus is equal to a predetermined target voltage when generating the transmitting power having the transmitting frequency determined, and controls the power supply circuit to generate the transmitting power having the transmitting frequency and voltage determined.

Abstract: A first detector detects a value of a current or voltage generated by an auxiliary coil. A second detector detects a value of a current flowing through a power transmitting coil. A coupling coefficient estimator estimates a first coupling coefficient between the power transmitting coil and a power receiving coil, based on the value of the current or voltage generated by the auxiliary coil, and estimates a second coupling coefficient between the power transmitting coil and the power receiving coil, based on the value of the current flowing through the power transmitting coil. A control circuit controls a power supply circuit to stop power transmission to a power receiver apparatus when a difference between the coupling coefficients is greater than a threshold.

Abstract: A control circuit controls a power supply circuit to generate transmitting power having a frequency varying within a frequency range. The control circuit determines a stably transmitting frequency based on a detected output voltage of a power receiver apparatus, the stably transmitting frequency indicating a frequency of the transmitting power at which dependency of the output voltage on a load value of the power receiver apparatus is at least locally minimized within the frequency range. The control circuit determines a transmitting voltage based on the detected output voltage, the transmitting voltage indicating a voltage of the transmitting power at which the output voltage reaches a target voltage when generating transmitting power having the stably transmitting frequency. The control circuit controls the power supply circuit to generate transmitting power having the stably transmitting frequency and the transmitting voltage.

Abstract: A resonance oscillator circuit is provided to include first and second oscillators. The first oscillator includes a first LC resonator circuit and an amplifier element, and oscillates by shifting a phase of an output voltage with a predetermined phase difference and feeding the output voltage back to the amplifier element. The second oscillator oscillates by generating a gate signal, which has a frequency identical to that of the output voltage, and drives the amplifier element, by shifting the phase of the output voltage with the phase difference and feeding the gate signal back to an input terminal of the amplifier element, by using the amplifier element as a switching element and using the first oscillator as a feedback circuit. The phase difference is a value substantially independent of an inductance of the first LC resonator circuit and a load, to which the output voltage is applied.

Abstract: A detection circuit detects at least one of a value of a current flowing through a power transmitting coil, and a value of a current or voltage generated by an auxiliary coil. A control circuit determines a transmitting frequency based on the value detected by the detection circuit, the transmitting frequency at least locally minimizing load dependence. The control circuit determines a voltage for the transmitting power at which an output voltage of a power receiver apparatus is equal to a predetermined target voltage when generating the transmitting power having the transmitting frequency determined, and controls the power supply circuit to generate the transmitting power having the transmitting frequency and voltage determined.

Abstract: A first detector detects a value of a current or voltage generated by an auxiliary coil. A second detector detects a value of a current flowing through a power transmitting coil. A coupling coefficient estimator estimates a first coupling coefficient between the power transmitting coil and a power receiving coil, based on the value of the current or voltage generated by the auxiliary coil, and estimates a second coupling coefficient between the power transmitting coil and the power receiving coil, based on the value of the current flowing through the power transmitting coil. A control circuit controls a power supply circuit to stop power transmission to a power receiver apparatus when a difference between the coupling coefficients is greater than a threshold.