Wireless power transmission device

Patent metadata

Field	Value
Publication number	US-2017194816-A1
Application number	US-201515314361-A
Country	US
Kind code	A1
Filing date	May 26, 2015
Priority date	May 29, 2014
Publication date	Jul 6, 2017
Grant date	—

Abstract

A comparator circuit compares a value of current detected by a current detector with a threshold. A first signal is output if the value is determined as to be equal to or more than the threshold. A second signal is output if the value is less than the threshold. Then, a logical operation is executed based on a signal output from the comparator circuit and the signal (oscillation signal, pause signal) output from a signal oscillator. When the power-shut off condition is met; i.e., the signal from the comparator circuit is the second signal and the signal from the signal oscillator is the pause signal, a turn-off control signal which turns off power supply to the power-supplying module is output to the oscillation output device, and a turn-on control signal which turns on the power supply to the power-supplying module is output to the oscillation output device otherwise.

First claim

1 . A wireless power transmission apparatus in which a transmission characteristic with respect to a power-source frequency of power, in a power-supplying resonator of a power-supplying module and a power-receiving resonator of a power-receiving module exhibits two peak bands, and
a relation between a transmission input impedance to a non-transmission input impedance satisfies a condition of the non-transmission input impedance>the transmission input impedance, while the power-source frequency is set to a frequency band corresponding to a peak band on a higher side out of the two peak bands of the transmission characteristic, the transmission input impedance being input impedance while wireless power transmission is taking place between the power-supplying module and the power-receiving module, and the non-transmission input impedance being an input impedance during a non-transmission period in which no wireless power transmission is taking place, said wireless power transmission apparatus comprising: an oscillation output device capable of switching on and off of power supply to the power-supplying module; a current detector configured to detect a value of current input from the oscillation output device to the power-supplying module; a comparator circuit configured to compare a value of current detected by the current detector with a threshold, output a first signal when the value of current detected by the current detector equals or surpasses the threshold, and output a second signal when the value of current detected by the current detector is smaller than the threshold, the threshold being set between a value of current input to the power-supplying module while wireless power supply is taking place between the power-supplying module and the power-receiving module and a value of current input to the power-supplying module while no wireless power transmission is taking place between the power-supplying module and the power-receiving module; a signal oscillator configured to execute an intermittent operation in which an alternate output of oscillation signal and a pause signal is repeated at a predetermined cycle; and a logic circuit configured to execute a logical operation based on a signal from the comparator circuit and a signal from the signal oscillator, wherein the logic circuit outputs a turn-off signal to the oscillation output device when the result of the logical operation meets a power-shut off condition such that the signal from the comparator circuit is the second signal and the signal from the signal oscillator is the pause signal, the turn-off control signal being a signal which turns off power supply of the oscillation output device to the power-supplying module, and wherein the logic circuit outputs a turn-on control signal when the result of the logical operation does not meet the power-shut off condition, the turn-on control signal being a signal which turns on power supply of the oscillation output device to the power-supplying module.

2 . The wireless power transmission apparatus according to claim 1 , wherein,
where the power-source frequency is set at a frequency band corresponding to the peak band on the high frequency side out of the two peak bands of the transmission characteristic, the transmission input impedance, the abnormality input impedance, and a standby input impedance of the power-supplying module satisfy the relations of: the standby input impedance>transmission input impedance; the abnormality input impedance>transmission input impedance, the transmission input impedance being the input impedance of the wireless power transmission apparatus while the power-supplying resonator and the power-receiving resonator are positioned to face each other and the abnormality input impedance the input impedance of the wireless power transmission apparatus while a metal foreign matter is disposed nearby the power-supplying resonator; wherein a threshold is set between a transmission input current value and a standby input current value when the abnormality input impedance≧the standby input impedance, the transmission input current value being a value of an input current while the wireless power transmission is taking place between the power-supplying module and the power-receiving module and the standby input current value being a value of an input current while no wireless power transmission is taking place between the power-supplying module and the power-receiving module, and the power-supplying module is in the standby state for power transmission; and wherein a threshold is set between the transmission input current value and an abnormality input current value when the standby input impedance>the abnormality input impedance, the transmission input current value being a value of an input current while the wireless power transmission is taking place between the power-supplying module and the power-receiving module and an abnormality input current value being a value of an input current while a metal foreign matter is disposed nearby the power-supplying resonator of the power-supplying module.

Assignees

• Nitto Denko Corp

Inventors

• Tsuda Hisashi
• Hatanaka Takezo
• Vu Nam Tung

Classifications

• H02J7/61

  against overcharge · CPC title

• H02J50/12 Primary

  of the resonant type · CPC title

• H02J7/025

  Electricity · mapped topic

• H02J50/80

  involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices · CPC title

• H02J7/045

  Electricity · mapped topic