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1. (US20140266036) Apparatus and method for detecting foreign object in wireless power transmitting system
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Claims

1. A method of detecting a foreign object using at least one processor included in a wireless power receiving apparatus, the method comprising:
performing a first operation of foreign object detection prior to an initial charging;
performing a second operation of foreign object detection during charging if the foreign object is not detected by the first operation of foreign object detection prior to the initial charging; and
performing a third operation of foreign object detection by temperature sensor if the foreign object is not detected by the second operation of foreign object detection during charging,
wherein the first operation of foreign object detection prior to the initial charging comprises:
receiving a power signal at an operating point from a wireless power transmitting apparatus which performs digital ping in a ping phase;
generating a signal strength packet indicating strength of the power signal at the operating point and transmitting the signal strength packet to the wireless power transmitting apparatus;
generating an identification packet indicating a unique ID of the wireless power receiving apparatus and configuration information of the wireless power receiving apparatus, and transmitting the identification packet and the configuration information to the wireless power transmitting apparatus;
measuring a received power and setting an initial voltage;
checking whether the wireless power receiving apparatus is charging;
comparing a required power value with the received power, generating a power control packet based on the comparison result, and transmitting the generated power control packet to the wireless power transmitting apparatus, if the wireless power receiving apparatus is charging;
checking whether the initial voltage is in a hold state and a steady state value of the initial voltage is within a predetermined reference voltage range, if the wireless power receiving apparatus is not charging; and
generating a foreign object state packet, and transmitting the foreign object state packet to the wireless power transmitting apparatus, if the initial voltage is in a hold state and the steady state value of the initial voltage is within the predetermined reference voltage range.
2. The method of claim 1, wherein the second operation of foreign object detection during charging comprises:
receiving wireless power from the wireless power transmitting apparatus if the foreign object is not detected by the wireless power transmitting apparatus.
3. The method of claim 1, wherein the second operation of foreign object detection during charging comprises:
receiving a transmission power measurement report indicating a measured transmission power from the wireless power transmitting apparatus;
detecting a foreign object based on a difference value between the measured transmission power and a measured reception power; and
transmitting an amplitude shift keying (ASK) signal comprising the foreign object detection result to the wireless power transmitting apparatus.
4. The method of claim 3, wherein the transmission power measurement report is transmitted as a frequency shift keying (FSK) signal, and the measured transmission power is obtained by measuring power generated by a primary coil of the wireless power transmitting apparatus.
5. The method of claim 4, wherein the FSK signal is transmitted at least once during each predetermined period, the predetermined period being an interval during which a predetermined number of data signals are transmitted.
6. The method of claim 4, wherein the FSK signal indicates 0 or 1 by switching or selecting a variable frequency of a predetermined range which converts a required fixed power frequency.
7. The method of claim 3, wherein the ASK signal further comprises a required power information as information requiring generation of wireless power based on a magnetic induction scheme by the wireless power transmitting apparatus.
8. A method of detecting a foreign object using at least one processor included in a wireless power receiving apparatus, the method comprising:
performing a first operation of foreign object detection prior to an initial charging; and
performing a second operation of foreign object detection by a temperature sensor if the foreign object is not detected by the first operation of foreign object detection prior to the initial charging,
wherein the first operation of foreign object detection prior to the initial charging comprises:
receiving a power signal at an operating point from a wireless power transmitting apparatus which performs digital ping in a ping phase;
generating a signal strength packet indicating strength of the power signal at the operating point and transmitting the signal strength packet to the wireless power transmitting apparatus;
generating an identification packet indicating a unique ID of the wireless power receiving apparatus and configuration information of the wireless power receiving apparatus and transmitting the identification packet and the configuration information to the wireless power transmitting apparatus;
measuring a received power and setting an initial voltage;
checking whether the wireless power receiving apparatus is charging;
comparing a required power value with the received power, generating a power control packet based on the comparison result, and transmitting the generated power control packet to the wireless power transmitting apparatus, if the wireless power receiving apparatus is charging;
checking whether the initial voltage is in a hold state and a steady state value of the initial voltage is within a predetermined reference voltage range, if the wireless power receiving apparatus is not charging; and
generating a foreign object state packet, and transmitting the foreign object state packet to the wireless power transmitting apparatus, if the initial voltage is in a hold state and the steady state value of the initial voltage is within the predetermined reference voltage range.
9. A wireless power receiving apparatus comprising:
a secondary core block;
a rectifying unit connected to the secondary core block;
a control unit; and
a temperature sensor,
wherein the rectifying unit performs full-wave rectification on an alternating current (AC) waveform generated by the secondary core block and provides power to the control unit and an external load,
wherein the control unit measures an initial voltage of an output terminal connected to the external load, and performs a first operation of foreign object detection if the initial voltage is within a reference voltage range, and
wherein if a foreign object is not detected before charging starts by the first operation of foreign object detection, the control unit performs a second operation of foreign object detection during charging, and if the foreign object is not detected during the second operation of foreign object detection during charging, the control unit performs a third operation of foreign object detection by the temperature sensor,
wherein the control unit performs the second operation of foreign object detection during charging by controlling the wireless power receiving apparatus to receive a transmission power measurement report indicating a measured transmission power from a wireless power transmitting apparatus, to detect the foreign object based on a difference value between the measured transmission power and a measured reception power, and to transmit an amplitude shift keying (ASK) signal comprising the foreign object detection result to the wireless power transmitting apparatus.
10. The wireless power receiving apparatus of claim 9, wherein the transmission power measurement report is transmitted as a frequency shift keying (FSK) signal, and the measured transmission power is obtained by measuring power generated by a primary coil of the wireless power transmitting apparatus.
11. The wireless power receiving apparatus of claim 10, wherein the FSK signal is transmitted at least once during each predetermined period, the predetermined period being an interval during which a predetermined number of data signals are transmitted.
12. The wireless power receiving apparatus of claim 10, wherein the FSK signal indicates 0 or 1 by switching or selecting a variable frequency of a predetermined range which converts a required fixed power frequency.
13. The wireless power receiving apparatus of claim 9, wherein the ASK signal further comprises a required power information as information requiring generation of wireless power based on a magnetic induction scheme by the wireless power transmitting apparatus.