Tdk Corporation

Kazuki Kondo

Akira Gotani

Kazunori Oshima

Narutoshi Fukuzawa

Masahide Ohnishi

A foreign object detection device includes a plurality of coils () each including a first conductive pattern mounted on one surface of a detection coil substrate () to be excited and thus generate a vibration signal, a detector () to detect the existence of a foreign object on the basis of the vibration signal, a first connecting line () to connect one terminals (T) of the individual coils () to the detector (), and a second connecting line () to connect the other terminals (T) of the individual coils () to the detector (). The first connecting line () and the second connecting line () extend in substantially identical paths in at least segments mounted on the detection coil substrate ().

Foreign object detection device, power transmission device, power reception device, and power transmission system

A foreign object detection device includes a detection coil unit including a detection coil substrate () and a plurality of coils (), which are mounted on a surface of the detection coil substrate () and each include a conductive pattern turned around the Z axis, and a detector () connected to the coils () to detect the existence of a foreign object on the basis of a vibration signal output when each of the coils () is excited. The coils () each define an opening. The detection coil substrate () has a through hole () extending through the detection coil substrate (), and a component space for accommodating a switch () or a wiring pattern (), within each of the openings of the coils () as seen in the Z-axis direction.

Foreign substance detection device, electricity transmission device, electricity reception device, and electric power transmission system

A power transmission device wirelessly transmits electric power to a power reception device. A power transmission coil is configured by winding a conductive wire. A foreign object detection device detects a foreign object. Sensor coils are placed to cover the power transmission coil. A detector executes determination processing of determining existence of the foreign object on each of the sensor coils, based on a comparison result between a comparison target value based on output voltage output from one sensor coil of the sensor coils and a threshold value set to the one sensor coil. The detector executes threshold value change processing of changing the threshold value set to the one sensor coil on each of the sensor coils, based on induced voltage induced in the one sensor coil by magnetic flux generated by the power transmission coil.

Power transmission device and electric power transmission system

A metallic foreign object detector is used in a wireless power transmission system that transmits power by wireless from a feeding coil to a receiving coil and includes an antenna coil, a capacitor that forms a resonance circuit together with the antenna coil, a vibration detection circuit configured to detect generation of a vibration signal in the resonance circuit, and a determination circuit that detects the presence/absence of a metallic foreign object according to the vibration signal. The vibration detection circuit is configured to output a detection state signal indicating the detection state of generation of the vibration signal. The determination circuit is configured to execute an operation of detecting the presence/absence of a metallic foreign object according to the detection state signal.

Metallic foreign object detector, wireless power transmitting device, wireless power receiving device, and wireless power transmission system

An object of the present invention is to suppress deterioration in detection accuracy during power feeding in the detection of the metallic foreign object using the antenna coil. A metallic foreign object detector includes: an antenna coil; a capacitor that constitutes a resonance circuit RC together with the antenna coil; a power supply that applies voltage to the resonance circuit to generate a vibration signal in the resonance circuit; a determination circuit that determines the presence/absence of a metallic foreign object based on the waveform of the vibration signal; a resonance capacitor switch inserted into the resonance circuit; and a control circuit that controls the open/close state of the resonance capacitor switch. The control circuit brings the resonance capacitor switch into a closed state responding to the power supply starting application of voltage to the resonance circuit.

An object of the present invention is to improve the accuracy of detection of the metallic foreign object. A metallic foreign object detector includes a sensor part having at least one antenna coil that receives a magnetic field or current to generate a vibration signal, an integration circuit that acquires the integral value of a waveform of a signal corresponding to the vibration signal, and a determination circuit that determines the presence/absence of a metallic foreign object approaching the antenna coil based on the integral value and a criterion integral value which is the integral value obtained in the absence of the approaching metallic foreign object. The integral value and the criterion integral value are obtained by integrating the waveform having the same wavenumber.

An object of the present invention is to reduce the possibility of failure in the detection of metallic foreign object. A metallic foreign object detector includes a sensor part having at least one antenna coil that receives a magnetic field or current to generate a vibration signal a vibration time length measurement circuit that measures a vibration time length indicating the length of time required for the vibration of the vibration signal output from the sensor part corresponding to a predetermined wavenumber larger than 1, and a determination circuit that determines the presence/absence of a metallic foreign object approaching the antenna coil based on the vibration time length and a criterion vibration time length which is the vibration time length obtained in the absence of the approaching metallic foreign object.

Wireless power transmitting device, wireless power receiving device, and wireless power transmission system

A metallic foreign object detector, used in a wireless power transmission system that transmits power using an alternating magnetic field, includes antenna coils that generate a vibration signal by receiving a magnetic field or current, one or more capacitors that constitute a resonance circuit together with each of the antenna coils, and a detection part that detects a metallic foreign object by sequentially using the antenna coils. The detection part has detection modes that detect the presence/absence of the metallic foreign object based on changes in mutually different characteristics of the resonance circuit. The detection part selects one mode from the detection modes in accordance with at least one of the power feeding state of the wireless power transmission system and the position of each of the plurality of antenna coils and performs the detection of the metallic foreign object in the selected detection mode.

An object of the present invention is to improve detection accuracy of a metallic foreign object between a feeding coil and a receiving coil during wireless power feeding. A wireless power transmitting device is a device that performs power transmission by wireless using an alternating magnetic field vibrating at a predetermined power transmission frequency and includes a feeding coil, an antenna coil, a capacitor that constitutes a resonance circuit RC together with the antenna coil, a noise detection part that detects noise vibrating at a frequency higher than the power transmission frequency, and a foreign object detection partthat detects the presence/absence of a metallic foreign object based on a change in voltage or current generated in the resonance circuit RC and a noise detection result from the noise detection part.

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Tokyo, Japan

Kazuki Kondo