Apparatus and method for detecting foreign objects in wireless power transmission system
Aspects of the present invention relate to an apparatus and method for detecting foreign objects in a wireless power transmission system. This specification provides a wireless power reception apparatus for detecting foreign objects, including a power measurement unit for generating required power information indicative of required power for the wireless power reception apparatus, sending the required power information to a wireless power transmission apparatus, and measuring power induced from the wireless power transmission apparatus and a secondary coil for receiving the power induced from the wireless power transmission apparatus. In accordance with the present invention, foreign objects intervened between the wireless power transmission apparatus and the wireless power reception apparatus are recognized, and a user removes the foreign objects. Accordingly, damage to a device attributable to foreign objects can be prevented.
1. A wireless power reception apparatus for detecting foreign objects, comprising:
a secondary coil configured to receive a requested amount of wireless power from a primary coil in a wireless power transmission apparatus; and
a power measurement circuit configured to:
during a reception of wireless power from the wireless power transmission apparatus, measure a plurality of measured power values indicative of an amount of power received from the wireless power transmission apparatus, and
detect that a foreign object has been placed in proximity of either the secondary coil or the primary coil during reception of the wireless power based on the plurality of measured power values being different from the requested amount of wireless power by at least a threshold for at least two consecutive measured power values.
2. The wireless power reception apparatus of claim 1 , wherein the power measurement circuit is further configured to inform the wireless power transmission apparatus to stop or suspend transmission of wireless power based on a detection that the foreign object has been placed in proximity of either the secondary coil or the primary coil.
3. The wireless power reception apparatus of claim 1 , wherein the power measurement circuit is further configured to send an indication to the wireless power transmission apparatus based on a detection of the foreign object.
4. The wireless power reception apparatus of claim 1 , wherein the power measurement circuit is further configured to:
determine a plurality of reception power measurement results based on the plurality of measured power values compared to the requested amount of wireless power and the threshold, and
detect the foreign object when at least two consecutive reception power measurement results are associated with measured power values being different from the requested amount of wireless power by at least the threshold.
5. The wireless power reception apparatus of claim 4 , wherein the plurality of reception power measurement results is based on a determination of whether a difference between each measured power value and the requested amount of wireless power is greater than, equal to, or smaller than the threshold.
6. The wireless power reception apparatus of claim 1 , wherein the secondary coil is magnetically or resonantly coupled with the primary coil.
7. The wireless power reception apparatus of claim 1 , wherein the power measurement circuit is further configured to send a foreign object detection (FOD) declaration in response to detecting that the foreign object has been placed in proximity of either the secondary coil or the primary coil.
8. A method for detecting foreign objects in a wireless power system, comprising:
receiving, by a secondary coil of a wireless power reception apparatus, a requested amount of wireless power from a primary coil in a wireless power transmission apparatus;
during a reception of wireless power from the wireless power transmission apparatus, measuring a plurality of measured power values indicative of an amount of power received from the wireless power transmission apparatus; and
detecting that a foreign object has been placed in proximity of either the secondary coil or the primary coil during reception of the wireless power based on the plurality of measured power values being different from the requested amount of wireless power by at least a threshold for at least two consecutive measured power values.
9. The method of claim 8 , further comprising informing, by the wireless power reception apparatus, the wireless power transmission apparatus to stop or suspend transmission of wireless power based on a detection that the foreign object has been placed in proximity of either the secondary coil or the primary coil.
10. The method of claim 8 , further comprising sending, by the wireless power reception apparatus, an indication to the wireless power transmission apparatus based on a detection of the foreign object.
11. The method of claim 8 , further comprising:
determining a plurality of reception power measurement results based on the plurality of measured power values compared to the requested amount of wireless power and the threshold; and
detecting the foreign object when at least two consecutive reception power measurement results are associated with measured power values being different from the requested amount of wireless power by at least the threshold.
12. The method of claim 11 , wherein the plurality of reception power measurement results is based on a determination of whether a difference between each measured power value and the requested amount of wireless power is greater than, equal to, or smaller than the threshold.
13. The method of claim 8 , further comprising sending a foreign object detection (FOD) declaration in response to detecting that the foreign object has been placed in proximity of either the secondary coil or the primary coil.