Wireless Power Transmitter, Wireless Power Repeater and Wireless Power Transmission Method

• US 20140252875A1
• Filed: 08/13/2012
• Published: 09/11/2014
• Est. Priority Date: 09/27/2011
• Status: Active Grant

• Current Assignee: LG Innotek Company Limited (LG Corporation)
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Lee, Jung Oh
• Granted Patent: US 10,205,351 B2
• Time in Patent Office: Days
• US Class Current: 307/104
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

Disclosed is a wireless power transmitter which wirelessly transmits power through a wireless power repeater to a wireless power receiver using resonance. The wireless power transmitter includes a power supply unit for outputting AC power having a predetermined frequency, a transmission coil for receiving the AC power to generate a time-variable magnetic field, and a transmission resonant coil unit for transmitting power received from the transmission coil coupled with the transmission resonant coil, wherein the wireless power transmitter determines a resonance frequency for a power transmission while controlling a frequency of the AC power output from the power supply unit and a resonance frequency of the transmission resonant coil unit.

Claims

1. A wireless power transmitter which wirelessly transmits power through a wireless power repeater to a wireless power receiver using resonance, the wireless power transmitter comprising:

a power supply unit for outputting AC power having a predetermined frequency;

a transmission coil for receiving the AC power to generate a time-variable magnetic field; and

a transmission resonant coil unit for transmitting power received from the transmission coil coupled with the transmission resonant coil,

wherein the wireless power transmitter determines a resonance frequency for a power transmission, controlling a frequency of the AC power output from the power supply unit and a resonance frequency of the transmission resonant coil unit.

2. The wireless power transmitter of claim 1, wherein the power supply unit outputs micro-power whose frequency is changed in a predetermined frequency interval at a predetermined time period.

3. The wireless power transmitter of claim 2, wherein the wireless power transmitter transmits the power through the wireless power repeater including a plurality of repeater resonant coils having resonance frequencies different from each other, and determines the resonance frequency for the power transmission based on the resonance frequencies of the repeater resonant coils matched to the resonance frequency of the wireless power receiver.

4. The wireless power transmitter of claim 3, further comprising:

a detecting unit for detecting an internal current value of the wireless power transmitter according to a micro-power transmission,

wherein the wireless power transmitter determines the resonance frequency based on the detected current value.

5. The wireless power transmitter of claim 4, wherein a frequency at which the detected current value is not greater than a reference current value is determined as the resonance frequency.

6. The wireless power transmitter of claim 3, wherein the wireless power receiver changes the resonance frequency at a time period the same as that of the wireless power transmitter.

7. The wireless power transmitter of claim 1, wherein the wireless power transmitter determines the resonance frequency while controlling frequencies the power supply unit and the transmission resonant coil unit such that the frequencies have a same value.

8. The wireless power transmitter of claim 2, wherein resonance frequencies of the wireless power transmitter and the wireless power receiver are set to have a same value for the predetermined time period.

9. The wireless power transmitter of claim 1, wherein the wireless power transmitter and the wireless power receiver fix self-resonance frequencies thereof based on the determined resonance frequency.

12. The wireless power transmitter of claim 4, wherein the detecting unit includes a detecting coil and a current detector.

13. The wireless power transmitter of claim 12,

wherein the detecting coil detects intensity of a magnetic field transmitted from the transmission resonant coil unit,

wherein the current detector converts a power generated by a magnetic field detected through the detecting coil into an electric current and detects a variation of an amount of current based on a converted electric current.

10. A wireless power repeater for relaying a power transmission between a wireless power transmitter and a wireless power receiver, the wireless power repeater comprising:

a plurality of repeater resonant coils having resonance frequencies different from each other,

wherein the wireless power repeater relays the power transmission through one of the repeater resonant coils corresponding to a resonance frequency of the wireless power transmitter and the wireless power receiver.

11. The wireless power repeater of claim 10, wherein the repeater resonant coils have frequencies which are set differently from each other in a predetermined frequency interval.

14. The wireless power repeater of claim 10, wherein each of the repeater resonant coils includes a shielding unit,

wherein the shielding unit surrounds an outer side of the repeater resonant coil and is disposed such that an upper side of the shielding unit is located at a position higher than an upper side of the repeater resonant coil.

15. A wireless power transmission method of a wireless power transmitter which wirelessly transmits power through a wireless power repeater to a wireless power receiver using resonance, the wireless power transmission method comprising:

transmitting micro-power having frequencies with a predetermined frequency interval to the wireless power repeater at a predetermined time period;

detecting an internal current value of the wireless power transmitter according to the transmitted micro-power; and

determining a resonance frequency for a power transmission based on the detected current value.

16. The wireless power transmission method of claim 15, wherein, in the determining of the resonance frequency, a frequency at which the detected current value is not greater than a reference current value is detected as the resonance frequency.

17. The wireless power transmission method of claim 15, further comprising:

fixing self-resonance frequencies of the wireless power transmitter to the determined resonance frequency.

18. The wireless power transmission method of claim 15, wherein the resonance frequency of the wireless power receiver is set to be equal to the resonance frequency of the wireless power transmitter for the predetermined time period.

19. The wireless power transmission method of claim 15, wherein the wireless power repeater includes a plurality of repeater resonant coils having resonance frequencies different from each other.

20. The wireless power transmission method of claim 15, further comprising:

transmitting the power to the wireless power receiver through one of the repeater resonant coils corresponding to the determined resonance frequency.