Tdk Corporation

Masahide Ohnishi

Ryo Miyazawa

Takuya Murashige

Kazunori Oshima

Masayuki Kobayashi

Akira Gotani

Kazuki Kondo

Takeshi Kamono

Masayuki Sugasawa

Akihiro Ii

Tadao Senriuchi

Kota Arasaki

Tsunehiro Saen

Kazutaka Tamaki

Shoma Asai

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

Disclosed herein is a leakage detector provided in a device having a conversion circuit that converts a DC voltage and an AC voltage from one to the other and a grounded metal member. The leakage detector comprises: an average voltage detection circuit that detects the average voltage of voltages corresponding to a potential difference between a high-voltage-side terminal or a low-voltage-side terminal on the DC side of the conversion circuit and the metal member; and a leakage detection circuit that detects the presence/absence of a leakage based on the average voltage detected by the average voltage detection circuit.

Leakage detector, wireless power transmitting device, wireless power receiving device, and wireless power transmission system

The coil unit includes a planar coil, a magnetic body and a capacitor module, the capacitor module has a substrate, capacitor elements mounted on the substrate, and a first connecting terminal and a second connecting terminal provided outside an element region on which capacitor elements are mounted, the first connecting terminal is provided inside a winding section as viewed in a plan view, the second connecting terminal is provided outside the winding section as viewed in a plan view, a direction in which the first connecting terminal and the second connecting terminal are connected is perpendicular to a direction in which the conductor extends in the winding section of the planar coil, the coil unit in which the element region is provided in a range overlapping the winding section of the coil as viewed in a plan view is selected.

Coil unit, wireless power transmission device, wireless power receiving 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 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.

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

A wireless power receiving device, for wirelessly receiving electric power from a wireless power feeding device, includes: a power receiving side resonant circuit having a power receiving coil wirelessly receiving power from a power feeding side and a power receiving side resonant capacitor; a rectifier circuit in which the power received by the power receiving coil is rectified to be output to a load; a power receiving side voltage detecting portion for detecting the output voltage of the rectifier circuit; a short circuit having a switching element connected between an output portion of the power receiving side resonant circuit and an output portion of the rectifier circuit, and a rectifying element inserted between the output portion of the power receiving side resonant circuit and the switching element; and a controlling circuit which operates the switching element when a value of the output voltage exceeds a preset reference voltage value.

Wireless power receiving device and wireless power transmission device

To provide a wireless power receiving device, and a wireless power transmission device capable of improving the reliability of a protection circuit while preventing breakage of a circuit element upon occurrence of any abnormality, such as overvoltage or overcurrent. A wireless power receiving device includes a power receiving coil; a rectifier unit that performs full-wave rectification of the power received by the power receiving coil and supplies the power to a load; power-receiving-side detecting unit that detects an output voltage value or an output current value from the rectifier unit; and switching unit that short-circuits one of two current paths through the rectifier unit if the value detected by the power-receiving-side detecting unit exceeds a predetermined reference value.

Wireless power receiving device having a short-circuiting switch, and wireless power transmission device

The present invention provides a contactless power transmission circuit which is capable of narrowing a fluctuation extent of an output voltage output by a power receiving coil via a rectifier circuit. The contactless power transmission circuit controls a period of an alternating voltage output from a driving circuit based on a smaller one of either of a first command value and a second command value. Here, the first command value is one based on a difference between a detected value of the output voltage from the rectifier circuit and a target value. The second command value is one calculated based on a difference between a detected value of a transmission current flowing through the power transmitting coil and a target value.

Contactless power transmission circuit

A wireless power receiving device includes a voltage detection unit that detects an output voltage value of a rectifying unit, a power reduction unit that includes a switching element connected to a charging unit in parallel, and a control unit that controls operations of the switching element. In a case where the output voltage value detected by the voltage detection unit exceeds a first reference voltage value set in advance, the control unit controls and turns the switching element on by applying a voltage to the switching element, and controls the value of the voltage to be applied to the switching element so that the difference between the voltage value calculated on the basis of a current flowing in the switching element and a second reference voltage value set in advance decreases.

Growing community of inventors

Tokyo, Japan

Masahide Ohnishi