POWER TRANSMISSION DEVICE AND WIRELESS POWER TRANSMISSION SYSTEM
First Claim
1. A power transmission device for transmitting power via electric field coupling to a power reception device having a pair of power reception electrodes, the power transmission device comprising:
- first and second power transmission electrodes that respectively oppose the pair of power reception electrodes with a gap therebetween, when the power reception device is positioned adjacent to the power transmission device;
a voltage detection circuit configured to monitor a voltage of one of the first and second power transmission electrode; and
a control circuit configured to determine an absolute value of a change per a time interval in the monitored voltage and to stop power transmission to the power reception device when the absolute value exceeds a predetermined threshold.
1 Assignment
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Accused Products
Abstract
A power transmission device applies a alternating-current voltage to an active electrode OPPOSING an active electrode of a power reception device with a gap therebetween, and to a passive electrode OPPOSING a passive electrode of the power reception device with a gap therebetween and transmits power via electric field coupling. The power transmission device includes a controller that monitors a voltage applied to the passive electrode. If a change in the voltage per unit time exceeds a threshold, the controller determines that a metal foreign object has become interposed between the active electrodes and a user has touched the metal foreign object, and stops the transmission of power to the power reception device. Thus, a power transmission device and a wireless power transmission system are provided that are capable of preventing with certainty a malfunction due to a foreign object when a foreign object has become interposed between electrodes.
6 Citations
20 Claims
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1. A power transmission device for transmitting power via electric field coupling to a power reception device having a pair of power reception electrodes, the power transmission device comprising:
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first and second power transmission electrodes that respectively oppose the pair of power reception electrodes with a gap therebetween, when the power reception device is positioned adjacent to the power transmission device; a voltage detection circuit configured to monitor a voltage of one of the first and second power transmission electrode; and a control circuit configured to determine an absolute value of a change per a time interval in the monitored voltage and to stop power transmission to the power reception device when the absolute value exceeds a predetermined threshold. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A wireless power transmission system comprising:
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a power reception device including a pair of power reception electrodes, and a voltage supply circuit configured to supply a voltage induced in the pair of power reception electrodes to a load; and a power transmission device including; first and second power transmission electrodes that respectively oppose the pair of power reception electrodes with a gap therebetween, when the power reception device is positioned adjacent to the power transmission device; a voltage detection circuit configured to monitor a voltage of one of the first and second power transmission electrode; and a control circuit configured to determine an absolute value of a change per a time interval in the monitored voltage and to stop power transmission to the power reception device when the absolute value exceeds a predetermined threshold. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method for transmitting power via electric field coupling from a power transmitting device having a pair of power transmitting electrodes to a power reception device having a pair of power reception electrodes, the method comprising:
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monitoring a voltage of one of the first and second power transmission electrode when the power reception device is positioned adjacent to the power transmission device; determining an absolute value of a change per a time interval in the monitored voltage; comparing the absolute value to a predetermined threshold; and stopping power transmission to the power reception device when the absolute value exceeds the predetermined threshold. - View Dependent Claims (17, 18, 19, 20)
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Specification