Wireless power transmitter and power transmission method thereof

• US 10,181,756 B2
• Filed: 04/20/2016
• Issued: 01/15/2019
• Est. Priority Date: 11/02/2011
• Status: Expired due to Fees

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Bae, Su Ho, Lee, Ki Min
• Primary Examiner(s): Amaya, Carlos
• Assistant Examiner(s): Evans, James
• Application Number:
  US15/133,670
• Publication Number:
  US 20160233724A1
• Time in Patent Office: 1,000 Days
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/502 the energy repeater being integrated together with the emitter or the receiver
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/263 Multiple coils at either side
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

Disclosed are a wireless power transmitter and a power transmission method thereof. The wireless power transmitter includes a plurality of transmission resonance units, a detection power applying unit applying detection power to the transmission resonance units to detect a location of the wireless power receiver, and a current measuring unit measuring current generating from an inner part of the wireless power transmitter based on the applied detection power. The wireless power transmitter transmits the power through at least one transmitting resonance unit corresponding to the location of the wireless power receiver based on the measured current.

Claims

1. A wireless power transmitter for wirelessly transmitting power to a wireless power receiver, the wireless power transmitter comprising:

a plurality of transmission resonance coils, each having a resonance frequency identical to that of the wireless power receiver;

a power supply unit;

a detection power applying unit;

a measuring unit;

a switch unit connected to the plurality of transmission resonance coils; and

a controller configured;

to control the detection power applying unit and the switch unit to sequentially supply a detection power having a first frequency to each of the plurality of transmission resonance coils, the first frequency being identical to the resonance frequency of each of the transmission resonance coils,

to control the measuring unit to measure a value of a current of each of the transmission resonance coils,

to compare the measured current value of each of the transmission resonance coils to a threshold current value,

to determine whether a location of at least one transmission resonance coil of the plurality of transmission resonance coils corresponds to a location of the wireless power receiver based on whether the measured current values of the transmission resonance coils are equal to or greater than the threshold current value, and

to control the power supply unit and the switch unit to supply a charging power having a second frequency to the determined at least one transmission resonance coil for charging of the wireless power receiver, the second frequency being a mutual-change resonance frequency changed from a resonance frequency due to a mutual inductance component between the respective transmission resonance coil and the wireless power receiver, the at least one transmission resonance coil being determined according to whether the measured current values are equal to or greater than the threshold current value,

wherein each of the plurality of transmission resonance coils comprises a variable capacitor for changing the resonance frequency of the transmission resonance coils,

wherein the threshold value is a minimum current value required to detect the wireless power receiver location,

wherein the plurality of transmission resonance coils is disposed on a pad in which the plurality of transmission resonance coils is divided and arranged in regions having an equal area, and

wherein the switch unit is disposed outside the pad.

2. The wireless power transmitter of claim 1, wherein the second frequency is different from the first frequency and the at least one of the plurality of transmission resonance coils having a location corresponding to a location of the wireless power receiver transmits the charging power having the second frequency to the wireless power receiver.

3. The wireless power transmitter of claim 2, wherein the second frequency is related to a frequency for receiving of the wireless power receiver.

4. The wireless power transmitter of claim 1, wherein the threshold current value is a previously determined current value.

5. The wireless power transmitter of claim 1, wherein the plurality of transmission resonance coils are spatially arranged across the pad.

6. The wireless power transmitter of claim 5, wherein the plurality of transmission resonance coils are arranged in a form of a lattice or a matrix.

7. A method of a wireless power transmitter for wirelessly transmitting power to a wireless power receiver to detect and charge the wireless power receiver, comprising:

sequentially applying a detection power having a first frequency to each of a plurality of transmission resonance coils, each of the plurality of transmission resonance coils having a resonance frequency identical to that of the wireless power receiver, and the first frequency being identical to the resonance frequency of each of the transmission resonance coils;

measuring a value of a current of each of the transmission resonance coils;

comparing the measured current value of each of the transmission resonance coils to a threshold current value; and

determining whether a location of at least one transmission resonance coil of the plurality of transmission resonance coils corresponds to a location of the wireless power receiver, based on whether the measured current values of the transmission resonance coils are equal to or greater than the threshold current value; and

supplying a charging power having a second frequency to the determined at least one transmission resonance coil for charging of the wireless power receiver, the second frequency being a mutual-change resonance frequency changed from a resonance frequency due to a mutual inductance component between the respective transmission resonance coil and the wireless power receiver, the at least one transmission resonance coil being determined according to whether the measured current values are equal to or greater than the threshold current value,

wherein each of the plurality of transmission resonance coils comprises a variable capacitor for changing a resonance frequency of the transmission resonance coils,

wherein a power having the second frequency for charging of the wireless power receiver is applied,

wherein an impedance variance is generated by the wireless power receiver,

wherein the second frequency is applied to the at least one of the plurality of transmission resonance coils having a location corresponding to the location of the wireless power receiver after the first frequency is applied, and

wherein the plurality of transmission resonance coils is disposed on a pad in which the plurality of transmission resonance coils is divided and arranged in regions having an equal area.

8. The method of claim 7, wherein the second frequency is related to a frequency for receiving of the wireless power receiver.

9. The method of claim 7, wherein the threshold current value is a minimum current value required to detect the wireless power receiver location.

10. The method of claim 7, further comprising repeatedly measuring the current value based on the impedance variance of each of the plurality of transmission resonance coils.