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EP-4742492-A2 - APPARATUS AND METHOD FOR PERFORMING POWER CALIBRATION IN WIRELESS POWER TRANSMISSION SYSTEM

EP4742492A2EP 4742492 A2EP4742492 A2EP 4742492A2EP-4742492-A2

Abstract

The present invention relates to an apparatus and a method for performing power calibration in a wireless power transmission system. The present specification provides a wireless power transmission apparatus comprising: a power conversion unit configured to transmit, in a power transfer phase, wireless power generated on the basis of magnetic coupling to a wireless power receiving device; and a communication/control unit configured to perform an initial calibration for a power parameter prior to the power transfer phase, receive a first received power packet from the wireless power receiving device indicating the power received by the wireless power receiving device during the power transfer phase, and detect foreign matter by using the received power and a first power loss determined on the basis of the initial calibration. It is possible to adaptively respond to a newly changed wireless charging environment to calibrate transmission power and reception power, and it is possible to detect foreign matter more precisely by detecting a power loss on the basis of the calibrated transmission and reception power.

Inventors

  • PARK, YONGCHEOL
  • PARK, JOONHO
  • YOOK, Gyunghwan

Assignees

  • LG Electronics Inc.

Dates

Publication Date
20260513
Application Date
20190108

Claims (9)

  1. A wireless power transmitter (100), comprising: a power conversion unit (110) configured to transmit wireless power to a wireless power receiver in a power transfer phase; and a communication/control unit (120) configured to: receive, from the wireless power receiver (200) in the power transfer phase, a first received power packet informing about a first received power value for power calibration, wherein a mode value of the first received power packet is 1, wherein the first received power value is a received power value under a light load condition and is close to a minimum expected output power, receive, from the wireless power receiver (200) in the power transfer phase, a second received power packet informing about a second received power value for power calibration, wherein a mode value of the second received power packet is 2, wherein the second received power value is a received power value under a connected load condition and is close to a maximum expected output power, receive, from the wireless power receiver (200) in the power transfer phase, a third received power packet informing about a third received power value for power calibration, wherein a mode value of the third received power packet is 2, construct an extended calibration curve based on multiple calibration data points related to the first received power value, the second received power value and the third received power value, after receiving the third received power packet having the mode value which is 2, and wherein, for an ACK in response to the third received power packet, the wireless power transmitter (100) is configured to wait for a power level to stabilize and the wireless power transmitter (100) is configured to transmit the ACK in response to the third received power packet after the power level is stabilized.
  2. The wireless power transmitter (100) of claim 1, wherein the third received power value is greater than the second received power value.
  3. The wireless power transmitter (100) of claim 1 or 2, wherein the wireless power transmitter (100) is configured to receive the third received power packet from the wireless power receiver with a time interval based on the wireless power transmitter (100) transmitting at least one NAK.
  4. The wireless power transmitter (100) of any one of claims 1 to 3, wherein the communication/control unit (120) is configured to transmit a bit pattern requesting an initiation of re-ping to the wireless power receiver (200) based on a change in the wireless power.
  5. The wireless power transmitter (100) of claim 4, wherein the communication/control unit (120) is configured to receive a re-ping initiation packet from the wireless power receiver (200) in response to the bit pattern.
  6. The wireless power transmitter (100) of claim 5, wherein the re-ping initiation packet includes an end power transfer, EPT, packet for initiating the re-ping.
  7. The wireless power transmitter (100) of claim 5 or 6, wherein the communication/control unit (120) is configured to: enter a re-ping phase based on the re-ping initiation packet, and perform calibration again in the re-ping phase.
  8. A method performed by a wireless power transmitter (100), the method comprising: receiving, from a wireless power receiver (200) in a power transfer phase, a first received power packet informing about a first received power value for power calibration, wherein a mode value of the first received power packet is 1, wherein the first received power value is a received power value under a light load condition and is close to a minimum expected output power; receiving, from the wireless power receiver (200) in the power transfer phase, a second received power packet informing about a second received power value for power calibration, wherein a mode value of the second received power packet is 2, wherein the second received power value is a received power value under a connected load condition and is close to a maximum expected output power; receiving, from the wireless power receiver (200) in the power transfer phase, a third received power packet informing about a third received power value for power calibration, wherein a mode value of the third received power packet is 2; and constructing an extended calibration curve based on multiple calibration data points related to the first received power value, the second received power value and the third received power value, after receiving the third received power packet having the mode value which is 2, wherein, for an ACK in response to the third received power packet, the wireless power transmitter (100) is configured to wait for a power level to stabilize and the wireless power transmitter (100) is configured to transmit the ACK in response to the third received power packet after the power level is stabilized.
  9. The method of claim 8, wherein the wireless power transmitter (100) further carries out the step of claims 2 to 7.

Description

[Technical Field] The present disclosure relates to wireless charging, and more particularly, to an apparatus and method for performing power calibration in a wireless power transfer system. [Background Art] The wireless power transfer (or transmission) technology corresponds to a technology that can wirelessly transfer (or transmit) power between a power source and an electronic device. For example, by allowing the battery of a wireless device, such as a smartphone or a tablet PC, and so on, to be recharged by simply loading the wireless device on a wireless charging pad, the wireless power transfer technique may provide more outstanding mobility, convenience, and safety as compared to the conventional wired charging environment, which uses a wired charging connector. Apart from the wireless charging of wireless devices, the wireless power transfer technique is raising attention as a replacement for the conventional wired power transfer environment in diverse fields, such as electric vehicles, Bluetooth earphones, 3D glasses, diverse wearable devices, household (or home) electric appliances, furniture, underground facilities, buildings, medical equipment, robots, leisure, and so on. The wireless power transfer (or transmission) method is also referred to as a contactless power transfer method, or a no point of contact power transfer method, or a wireless charging method. A wireless power transmission system may be configured of a wireless power transmitter supplying electric energy by using a wireless power transfer method, and a wireless power receiver receiving the electric energy being supplied by the wireless power transmitter and supplying the receiving electric energy to a receiver, such as a battery cell, and so on. The wireless power transfer technique includes diverse methods, such as a method of transferring power by using magnetic coupling, a method of transferring power by using radio frequency (RF), a method of transferring power by using microwaves, and a method of transferring power by using ultrasound (or ultrasonic waves). The method that is based on magnetic coupling is categorized as a magnetic induction method and a magnetic resonance method. The magnetic induction method corresponds to a method transmitting power by using electric currents that are induced to the coil of the receiver by a magnetic field, which is generated from a coil battery cell of the transmitter, in accordance with an electromagnetic coupling between a transmitting coil and a receiving coil. The magnetic resonance method is similar to the magnetic induction method in that is uses a magnetic field. However, the magnetic resonance method is different from the magnetic induction method in that energy is transmitted due to a concentration of magnetic fields on both a transmitting end and a receiving end, which is caused by the generated resonance. A wireless power transmitter and a wireless power receiver include various circuit components provided therein and are constituted as independent devices from each other, but since the wireless power transfer is performed by magnetically coupling between the wireless power transmitter and the wireless power receiver, the wireless power transmitter and the wireless power receiver constitute one wireless power transfer system. However, an error may occur between the transmitted power and received power due to a change in the magnetic coupling according to the actual use environment (signal size, frequency, and duty cycle applied to the wireless power transfer system, distance/position alignment between Tx and the Rx, and the like) of Tx and Rx as well as unique physical characteristics of the wireless power transfer system. The error may be an obstacle to a sophisticated detection of foreign object. Therefore, there is a need for a method of calibrating transmitted power and received power by reflecting the unique characteristics of the wireless power transfer system and the change in the actual use environment, and performing more sophisticated FOD based on the calibrated transmitted power and received power. [Disclosure] [Technical Problem] The technical problem of the present disclosure is to provide an apparatus and method for performing power calibration in a wireless power transfer system. Another technical problem of the present disclosure is to provide an apparatus and method for adaptively performing power calibration in response to a change in load and performing a detection of foreign object. Still another technical problem of the present disclosure is to provide an apparatus and method for adaptively performing power calibration in response to a change in magnetic coupling between a wireless power transmitter and a wireless power receiver, and performing a detection of foreign objects. [Technical Solution] According to an aspect of the present disclosure, there is provided a wireless power transmitter including a power conversion unit configured to transmit wireless