Wireless power transmitter and wireless power transfer method thereof in many-to-one communication

• US 9,306,401 B2
• Filed: 06/29/2012
• Issued: 04/05/2016
• Est. Priority Date: 06/29/2011
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Lee, Jaesung, Lee, Hyunbeom, Lee, Jun, Seo, Jeongkyo
• Primary Examiner(s): Fureman, Jared
• Assistant Examiner(s): Yeshaw, Esayas
• Application Number:
  US13/538,263
• Publication Number:
  US 20130057078A1
• Time in Patent Office: 1,376 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: H02J 2310/22 The load being a portable electronic device
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H02J 7/00036 Charger exchanging data with battery
• CPC Class Codes: H02J 7/00047 with provisions for charging different types of batteries
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/007192 in response to temperature
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

A wireless power transmitter for transmitting power in a wireless manner by forming a wireless power signal and a wireless power transfer method thereof are capable of optimizing transmission efficiency for a plurality of wireless power receivers, by deciding an optimal transmission parameter (especially, a frequency corresponding to the wireless power signal or a resonant frequency) for the plurality of wireless power receivers based on control errors received from the plurality of wireless power receivers, respectively, via respective time slots allocated to the plurality of wireless power receivers.

Claims

1. A wireless power transfer method for a wireless power transmitter which transfers power in a wireless manner by forming a wireless power signal, the method comprising:

detecting a plurality of wireless power receivers;

acquiring control errors corresponding to a first control error value and a second control error value from the detected plurality of wireless power receivers, respectively;

detecting transmission parameters corresponding to the plurality of wireless power receivers, respectively, based on the first control error value and the second control error value; and

transferring power in the wireless manner to each of the plurality of wireless power receivers by forming the wireless power signal based on the detected transmission parameters,

wherein the first control error value is received from a first wireless power receiver in a first time duration which is allocated to the first wireless power receiver and the second control error value is received from a second wireless power receiver in a second time duration which is allocated to the second wireless power receiver.

2. The method of claim 1, wherein the control error corresponding to each of the plurality of wireless power receivers is generated based on at least one of a value obtained by subtracting an actually received amount of power from a target amount of power corresponding to each of the plurality of wireless power receivers, a value obtained by subtracting an actually received receiving side voltage from a target receiving side voltage corresponding to each of the plurality of wireless power receivers, a value obtained by subtracting an actually received receiving side current from a target receiving side current corresponding to each of the plurality of wireless power receivers, a value obtained by subtracting transmission efficiency upon actually receiving power in a wireless manner from a target transmission efficiency corresponding to each of the plurality of wireless power receivers, and a value obtained by subtracting a transmission gain upon actually receiving power in a wireless manner from a target transmission gain corresponding to each of the plurality of wireless power receivers.

3. The method of claim 2, wherein the transmission efficiency is a ratio between transmission power of the wireless power transmitter and reception power corresponding to each of the plurality of wireless power receivers,

wherein the transmission gain is a ratio between a transmitting side voltage corresponding to the wireless power transmitter and a receiving side voltage corresponding to each of the plurality of wireless power receivers, and

wherein the reception power is detected based on a receiving side voltage and a receiving side current corresponding to each of the plurality of wireless power receivers.

4. The method of claim 1, wherein each of the plurality of wireless power receivers transmits a packet to the wireless power transmitter, the packet including a power control message,

wherein the control error is transmitted to the wireless power transmitter by being included in the packet, the packet including the power control message, and

wherein the packet including the power control message is generated by modulating the wireless power signal by each of the plurality of wireless power receivers.

5. The method of claim 1, wherein the transmission parameter is at least one of a frequency, an amplitude and a phase of the wireless power signal, and a time interval for transmission of the wireless power signal.

6. The method of claim 1, wherein the transmission parameter is a transmission frequency corresponding to each of the plurality of wireless power receivers,

wherein the transferring of the power in the wireless manner based on the detected transmission parameters comprises:

periodically changing the frequency of the wireless power signal to a transmission frequency corresponding to each of the plurality of wireless power receivers; and

transferring power in the wireless manner by forming the wireless power signal using the periodically changed transmission frequency.

7. The method of claim 1, wherein the transferring of the power in the wireless manner based on the detected transmission parameters comprises:

detecting an optimal transmission parameter corresponding to the plurality of wireless power receivers based on the detected transmission parameters; and

transferring power in the wireless manner to the plurality of wireless power receivers by forming the wireless power signal based on the optimal transmission parameter.

8. The method of claim 7, wherein the optimal transmission parameter is generated by processing the detected transmission parameters in a statistical manner.

9. The method of claim 8, wherein the statistical manner is a method based on at least one of an average, variance and standard deviation of the transmission parameters.

10. The method of claim 1, wherein the transmission parameter is a transmission frequency corresponding to each of the plurality of wireless power receivers,

wherein the transferring of the power in the wireless manner based on the detected transmission parameters comprises:

setting a weight for each of the plurality of wireless power receivers based on the control errors or the detected transmission parameters;

setting a transmission time interval for each of the plurality of wireless power receivers based on the weights; and

transferring power in the wireless manner by forming the wireless power signal having the transmission frequency corresponding to each of the plurality of wireless power transmitters for the set transmission time interval.

11. The method of claim 1, wherein the transmission parameters are detected based on a first weight and a second weight proportional to the first control error value and the second control error value.

12. The method of claim 1, wherein the transmission parameter is decided as a value that the control error of each of the plurality of wireless power receivers is less than a reference value.

13. The method of claim 1, wherein the transmission parameter is decided as a value that a control error value of a specific wireless power receiver of the plurality of wireless power receivers does not increase more than a specific value.

14. The method of claim 1, wherein the transmission parameter is decided based on at least one of whether or not a damage is caused on the plurality of wireless power receivers or whether or not the plurality of wireless power receivers are able to wirelessly receive power from the wireless power transmitter.

15. The method of claim 1, further comprising transmitting a control error transmission request to each of the plurality of wireless power receivers.

16. The method of claim 15, wherein the control error transmission request is transmitted when the control error is more than a reference value, when a new wireless power receiver is placed in a specific area, when the number of wireless power receivers existing in the specific area changes, when a position of at least one wireless power receiver existing in the specific area changes, and when there is a periodically received request or a request received from the wireless power receiver,

wherein the specific area is an area through which the wireless power signal passes or an area on which the wireless power receiver is sensed.

17. The method of claim 1, wherein each of the plurality of wireless power receivers transmits the control error to the wireless power transmitter via each time slot corresponding thereto,

wherein the time slot is formed by dividing a time section for transmission of the wireless power signal by a time axis so as to be allocated to each of the plurality of wireless power receivers.

18. The method of claim 17,

wherein the wireless power transmitter acquires a first control error value via a time slot corresponding to the first wireless power receiver, so as to detect a first transmission parameter corresponding to the first wireless power receiver,

wherein the wireless power transmitter acquires a second control error value via a time slot corresponding to the second wireless power receiver, so as to detect a second transmission parameter corresponding to the second wireless power receiver, and

wherein the wireless power transmitter transfers power in the wireless manner to the first and second wireless power receivers by forming the wireless power signal based on the first and second transmission parameters.

19. A wireless power transmitter comprising:

a power conversion unit configured to detect a plurality of wireless power receivers, receive a first control error value from a first wireless power receiver in a first time duration which is allocated to the first wireless power receiver and receive a second control error value from a second wireless power receiver in a second time duration which is allocated to the second wireless power receiver; and

a controller configured to acquire control errors corresponding to the first control error value and the second control error value from the detected plurality of wireless power receivers, respectively, detect transmission parameters corresponding to the plurality of wireless power receivers, respectively, based on the first control error value and the second control error value, and control the power conversion unit to transmit power in a wireless manner to each of the plurality of wireless power receivers by forming the wireless power signal based on the detected transmission parameters.

20. The transmitter of claim 19, wherein the controller sequentially acquires the control errors from the plurality of wireless power receivers, respectively, the control error corresponding to each of the plurality of wireless power receivers, and

wherein the controller detects the transmission parameters corresponding to the plurality of wireless power receivers, respectively, based on the sequentially acquired control errors, detects an optimal transmission parameter corresponding to the plurality of wireless power receivers based on the detected transmission parameters, and controls the power transmission unit to transmit power in a wireless manner to the plurality of wireless power receivers by forming the wireless power signal based on the optimal transmission parameter.

21. The transmitter of claim 20, wherein the optimal transmission parameter is decided as an average value of the transmission parameters corresponding to the plurality of wireless power receivers, respectively.

22. The transmitter of claim 20, wherein the control error is generated based on a value obtained by subtracting an actually received receiving side voltage from a target receiving side voltage corresponding to each the plurality of wireless power receivers,

wherein each of the plurality of wireless power receivers transmits a packet to the wireless power transmitter, the packet including information related to the control error, and

wherein the packet is generated by modulating the wireless power signal by each of the plurality of wireless power receivers.

23. The transmitter of claim 19, wherein the controller further detects transmission parameters based on a first weight and a second weight proportional to the first control error value and the second control error value.