Tdk Corporation

Ryo Miyazawa

Akihiro Ii

Kazunori Oshima

Masahide Ohnishi

Shinya Ofuji

Kenji Furukawa

Tsunehiro Saen

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 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 reception device includes: a power receiving coil coupled to a transmitting coil; a first rectifier circuit rectifies AC voltage supplied from the receiving coil and outputs to a load; a first capacitor connected between 11th and 12th output terminals respectively on high and low potential sides among output terminals in the first rectifier circuit and the first rectifier circuit and the load; a second rectifier circuit connected to the receiving coil parallel to the first and rectifies AC voltage supplied from the receiving coil; a second capacitor connected between 21st and 22nd output terminals respectively on the high and low potential sides among second rectifier circuit output terminals; a second voltage detecting circuit detects voltage between the 21st and 22nd output terminals; and a position detecting circuit detects the receiving coil position relative to the power transmitting coil by voltage detected by the second voltage detecting circuit.

Wireless power reception device and wireless power transmission system

A wireless power reception device detects a power receiving coil position relative to a power transmitting coil while curbing an increase in power loss. The wireless power reception device includes: a power receiving coil magnetically coupled to the power transmitting coil; a first rectification and smoothing circuit rectifying an AC voltage supplied from the power receiving coil and outputs the rectified AC voltage to a load; first and second capacitors respectively connected to first and second transmission lines; a first resistor having one terminal connected to the first capacitor and the other terminal is supplied with a predetermined reference potential; a second resistor having one terminal connected to the second capacitor and the other terminal is supplied with the reference potential; and a position detecting circuit detecting the power receiving coil position relative to the power transmitting coil on the basis of first and second junction point potentials.

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.

Growing community of inventors

Tokyo, Japan

Ryo Miyazawa