Energy transmission apparatus and method

• US 9,866,065 B2
• Filed: 09/30/2011
• Issued: 01/09/2018
• Est. Priority Date: 09/30/2010
• Status: Active Grant

• 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): BARNIE, REXFORD N
• Assistant Examiner(s): Inge, Joseph
• Application Number:
  US13/876,969
• Publication Number:
  US 20130187478A1
• Time in Patent Office: 2,293 Days
• Field of Search: 307104
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/50 using additional energy repeaters between transmitting devices and receiving devices
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

An apparatus and method for wirelessly transmitting electromagnetic energy are provided. The apparatus includes a power source, a transmission unit, and a measurement unit. The power source supplies a power according to a certain frequency. The transmission unit receives the power to wirelessly transmit the received power through self resonance. The measurement unit measures a phase difference between a voltage and current of the transmission unit. The certain frequency is controlled according to the phase difference. Accordingly, the apparatus and method control only the frequency of the power supply when a resonance frequency is changed by the change of an ambient environment, thus enhancing energy transmission efficiency.

Claims

1. A wireless power transmission apparatus comprising:

a power source supplying a power having an AC voltage and a default frequency;

a transmission unit receiving the power from the power source and generating a magnetic field to transfer energy to a reception unit including a first reception unit and a second reception unit; and

a measurement unit measuring a phase difference between a voltage and a current inputted to a transmission coil included in the transmission unit;

wherein the default frequency corresponds to a resonant frequency of the transmission unit without the reception unit being located on an energy transfer path;

wherein the wireless power transmission apparatus determines whether the reception unit is located on the energy transfer path by determining a change of the resonant frequency of the transmission unit, wherein the reception unit is determined as being located on an energy path if the resonant frequency of the transmission unit is changed from the default frequency;

wherein the wireless power transmission apparatus adjusts the default frequency to the resonant frequency such that the phase difference between the voltage and the current of the transmission unit becomes zero when the phase difference is greater than zero or a predetermined phase difference threshold value;

wherein one end of the power source is connected to one end of the transmission coil, and the other end of the power source is connected to the other end of the transmission coil; and

wherein one end of the measurement unit connects the one end of the power source and the one end of the transmission coil, and the other end of the measurement unit connects the other end of the power source and the other end of the transmission coil.

2. The wireless power transmission apparatus according to claim 1,

wherein the transmission coil generates the magnetic field.

3. The wireless power transmission apparatus according to claim 1, wherein the transmission unit further comprises a transmission resonance coil which amplifies the magnetic field generated by the transmission coil by resonating the magnetic field.

4. The wireless power transmission apparatus according to claim 3, wherein in an entire system comprising an energy transmission apparatus and an energy consumption apparatus,

the certain frequency (ω

) is expressed as Equation below,

5. The wireless power transmission apparatus according to claim 1, wherein the energy is transmitted by a non-radiative scheme.

12. The wireless power transmission apparatus according to claim 1, wherein the predetermined phase difference threshold value is within a range from −

0.1 radian to +0.1 radian, the default frequency not being changed.

6. A method of transmitting electromagnetic energy, the method comprising:

generating a power having an AC voltage and a default frequency, by a power source, to transmit the power to a transmission unit, wherein the default frequency corresponds to a resonant frequency of the transmission unit without a reception unit being located on an energy transfer path;

measuring a phase difference between a voltage and a current inputted to a transmission coil included in the transmission unit;

determining whether the reception unit is located on the energy transfer path by determining a change of the resonant frequency of the transmission unit, wherein the reception unit is determined as being located on the energy transfer path if the resonant frequency of the transmission unit is changed from the default frequency; and

adjusting the default frequency to the resonant frequency such that the phase difference between the voltage and the current of the transmission unit becomes zero when the phase difference is greater than zero or a predetermined phase difference threshold value.

7. The method according to claim 6, wherein the transmission unit transfers energy to the second reception unit through the first reception unit.

8. The method according to claim 6, wherein the reception unit is determined as being located on the energy transfer path, when the resonant frequency is different from the default frequency.

9. The method according to claim 6,

wherein the transmission coil generates the magnetic field.

10. The method according to claim 6, wherein in an entire system comprising an energy transmission apparatus and the energy consumption apparatus,

the resonant frequency (ω

) is expressed as Equation below,

11. The method according to claim 6, wherein the energy is transmitted by a non-radiative scheme.

13. The method according to claim 6, wherein the predetermined phase difference threshold value is within a range from −

0.1 radian to +0.1 radian, the default frequency not being changed.