WIRELESS POWER TRANSFER METHOD, APPARATUS AND SYSTEM

• US 20160308397A1
• Filed: 02/06/2015
• Published: 10/20/2016
• Est. Priority Date: 02/07/2014
• Status: Active Grant

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: JUNG, Byungsang, LEE, Hyunbeom, LEE, Seonghun, PARK, Yongcheol
• Granted Patent: US 10,256,666 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 7/007182 in response to battery voltage
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

The present disclosure relates to a wireless power reception method, a wireless power reception apparatus, and a wireless charging system in a wireless power transmission and reception field, and the wireless power reception apparatus may include a power receiving unit configured to change a magnetic flux to a current to receive power in a wireless manner, and a power controller connected to the power receiving unit to change a resonant frequency to control power received from the power receiving unit, wherein the power controller includes a first capacitor, a second capacitor connected to the first capacitor in parallel, a first switch connected to the second capacitor in series to flow a current in a first direction, a second switch configured to flow a current in a second direction opposite to the first direction, and a switch controller configured to control the first and the second switch.

Claims

1. A wireless power receiver for receiving power in a wireless manner, the wireless power receiver comprising:

a power receiving unit configured to change a magnetic flux to a current to receive power in a wireless manner; and

a power controller connected to the power receiving unit to determine a resonant frequency to control power received from the power receiving unit,

wherein the power controller comprises;

a first capacitor;

a variable capacitor unit comprising a first switch and a second switch connected to a second capacitor in series, and connected to the first capacitor in parallel; and

a switch controller connected to the first and the second switch to control the first and the second switch, and

the switch controller controls the first and the second switch to allow an equivalent capacitor value corresponding to the variable capacitor unit and the first capacitor to have a capacitor value corresponding to the determined resonant frequency.

2. The wireless power receiver of claim 1, wherein the switch controller adjusts an effective duty of the first and the second switch to have a capacitor value corresponding to a preset resonant frequency.

3. The wireless power receiver of claim 2, wherein an equivalent capacitor value calculated using the first and the second capacitor increases based on the effective duty of the first and the second switch being lengthened, and

the equivalent capacitor value decreases based on the effective duty of the first and the second switch being shortened.

4. The wireless power receiver of claim 2, wherein the switch controller closes the first switch during at least part of a section in which a voltage of the first capacitor increases, and closes the second switch during at least part of a section in which a voltage of the first capacitor decreases.

5. The wireless power receiver of claim 4, wherein an effective duty of the first and the second switch comprises a time point at which a voltage value of the first capacitor becomes zero.

6. The wireless power receiver of claim 1, wherein a time point at which either one of the first and the second switch is closed is a time point at which an absolute value of the voltage of the first capacitor has a larger value than that of the voltage of the second capacitor.

7. The wireless power receiver of claim 6, wherein the switch controller closes the first and the second switch at a time point prior to a time point indicating the effective duty of the first and the second switch.

8. A control method of a wireless power receiver configured to receive power in a wireless manner, and comprising a first capacitor, a second capacitor connected to the first capacitor in parallel, a first switch and a second switch, the method comprising:

receiving wireless power having a specific operating frequency through a power receiving unit from a wireless power transmitter;

calculating a resonant frequency to receive at least part of the received power through a power controller;

detecting a capacitor value corresponding to the resonant frequency to allow the wireless power receiver to have the resonant frequency;

detecting an effective duty value of a first switch and a second switch connected to the second capacitor in series to allow an equivalent capacitor value calculated using the first capacitor and the second capacitor to have the detected capacitor value; and

controlling the first and the second switch based on the effective duty value.

9. The method of claim 8, wherein said controlling the first and the second switch controls the first and the second switch to open the first and the second switch prior to a time section occupied by the effective duty.

10. A wireless power transmitter for transmitting power in a wireless manner, the wireless power transmitter comprising:

a power transmission unit having a plurality of coils configured to change a current to a magnetic flux to transmit power in a wireless manner, a plurality of sub-half bridges connected to the plurality of coils, respectively, and a main half bridge connected to all the plurality of sub-half bridges; and

a power transmission controller configured to control at least one coil to transmit power to a wireless power receiver using at least one of the plurality of coils,

wherein the power transmission controller performs a phase shifted full bridge control using at least one sub-half bridge connected to the at least one coil and the main half bridge.

11. The wireless power transmitter of claim 10, wherein the power transmission controller controls power through a phase difference of voltage applied to the sub-half bridge based on a reference voltage applied to the main half bridge.

12. The wireless power transmitter of claim 11, wherein the power transmission controller transmits maximum power to the wireless power receiver when a voltage applied to the main half bridge and a voltage applied to the sub-half bridge have a phase difference of 180 degrees.

13. The wireless power transmitter of claim 11, wherein a voltage applied to the sub-half bridge is determined by an amount of power transmitted from a coil connected to the sub-half bridge.

14. The wireless power transmitter of claim 10, wherein the power transmission controller controls voltages applied to a plurality of sub-half bridges connected to the at least one coil to have different voltages.

15. The wireless power transmitter of claim 10, wherein the power transmission controller controls a sub-half bridge to allow a voltage applied to the sub-half bridge connected to a coil that does not transmit power among the plurality of coils to have the same phase as a reference voltage applied to the main half bridge.