Tdk Corporation

Akihiro Ii

Ryo Miyazawa

Kazunori Oshima

Ken Matsuura

Masahide Ohnishi

Yasuhiro Ozawa

An object detection apparatus includes a sensor module including a sensor, and a controller that controls the sensor and generates output information, based on a signal that the sensor outputs; and a detector that determines presence or absence of the object, based on the output information. The detector executes a reference object detection process of detecting a reference object existing at a predetermined position within the detection range, by comparing the output information and predetermined reference information, and, when the reference object is detected, executes a correction process of correcting at least one of the output information or a parameter for the sensor, based on the reference information and reference object information that is information indicative of the reference object in the output information.

Object detection apparatus, power transmission apparatus, and power transmission system

A power supply circuit supplies AC power to a power-transmitting coil. A power-transmitting coil unit includes the power-transmitting coil and transmits AC power to a power receiving device. The power-transmitting coil unit executes first power transmission and second power transmission in which AC power received by the power receiving device is less than the AC power in the first power transmission and executes the second power transmission before executing the first power transmission.

Power transmission device and power transmission system

Disclosed herein is a wireless power receiving device including a detection circuit that detects a circuit characteristic value of the power receiving circuit and a position detection circuit that detects a state of the relative position between the power receiving coil and the power transmitting coil. The position detection circuit determines that the power receiving coil exists near the periphery of a position suitable for receiving power when the circuit characteristic value exceeds a first threshold value set between the peak value of the second peak and a detection limit value of the detection circuit, and calculates transmittable power from the wireless power transmitting device based on the circuit characteristic value, when the circuit characteristic value detected by the detection circuit exceeds a second threshold value set between the peak value of the second peak and the peak value of the first peak.

Wireless power receiver and wireless power transmission system

A coil unit capable of inhibiting overheating in a magnetic body while the amount of the magnetic body used is reduced includes a magnetic body and a coil with an opening, the magnetic body overlaps the coil in a first direction and includes first, second, and third areas, the first area includes first and second faces, the second area includes third and fourth faces, the third area includes fifth and sixth faces, a first distance between the fifth face and the coil is shorter than a second distance between the second face and the coil and is longer than a third distance between the first face and the coil, a fourth distance between the third face and the coil is shorter than the first distance, and a fifth distance between the fourth face and the coil is longer than the third distance.

Coil unit, wireless power transmission device, wireless power receiving device, and wireless power transmission system

A wireless power transmitting device transmits power by wireless to a wireless power receiving device through magnetic coupling between a feeding coil and a receiving coil and includes: a feeding circuit including a power conversion circuit that converts DC power into AC power of a drive frequency and a feeding coil unit including the feeding coil that receives the AC power supplied from the power conversion circuit to generate an AC magnetic field; and a control circuit Stu that controls the amount of magnetic flux generated from the feeding coil. The control circuit Stu calculates a separation distance between the feeding and receiving coils in their opposing direction from the circuit characteristic value of the wireless power transmitting device in a state where the amount of magnetic flux generated from the feeding coil is controlled so as to be constant.

Wireless power transmitting device and wireless power transmission system

A wireless power receiver is provided with a power reception unit, a rectifier circuit including first to fourth diodes and first and second capacitors and converting AC power into DC, an anode of the first diode and a cathode of the second diode being connected to one output end of the power reception unit, an anode of the third diode and a cathode of the fourth diode being connected to the other output end thereof, and first and second capacitors being connected in parallel, respectively, to the third and fourth diodes, a protection circuit including a first switching element connected between the other output end of the power reception unit and an output end of the rectifier circuit, and a control circuit that controls the first switching element based on output voltage of the rectifier circuit and inter-terminal voltage of the first or second capacitor.

Wireless power receiver and wireless power transmission system using the same

A wireless power transmission system includes a power feeding device and a power receiving device, wherein the power feeding device includes: a power feeding coil which receives an electric power to generate an AC magnetic field; an inverter for supplying an alternating-current power under a predetermined driving frequency to the power feeding coil; a current detection circuit for detecting a peak value of an alternating current flowing in the power feeding coil; and a controller for controlling the alternating current flowing in the power feeding coil. The power receiving device includes: a power receiving coil for receiving electric power wirelessly via the AC magnetic field; a power receiving side resonance capacitor which configures a power receiving side LC resonance circuit together with the power receiving coil; and a rectifier for rectifying the electric power received by the power receiving coil.

Growing community of inventors

Tokyo, Japan

Akihiro Ii