Resonance-based wireless power transfer system

• US 9,368,274 B2
• Filed: 03/16/2013
• Issued: 06/14/2016
• Est. Priority Date: 04/11/2012
• Status: Active Grant

• Current Assignee: Huazhong University of Science & Technology, University Of Pittsburgh (University of Pittsburgh of The Commonwealth System of Higher Education)
• Original Assignee: Huazhong University of Science & Technology, University Of Pittsburgh (University of Pittsburgh of The Commonwealth System of Higher Education)
• Inventors: Xu, Qi, Wang, Hao, Mao, Zhihong, Sun, Mingui, He, Jiping
• Primary Examiner(s): Tran, Thienvu
• Assistant Examiner(s): Sun, Pinping
• Application Number:
  US13/844,838
• Publication Number:
  US 20130293025A1
• Time in Patent Office: 1,186 Days
• US Class Current: 1/1
• CPC Class Codes: A01K 1/031 Cages for laboratory animals; Cages for measuring metabolism of animals
• CPC Class Codes: A01K 11/006 Automatic identification systems for animals, e.g. electronic devices, transponders for animals identification systems for access to feeding pens A01K1/0209; ear tags with electronic identification means A01K11/004
• 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 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment

Abstract

A wireless power transfer system including a driver coil array, a hexagonally-packed transmitter mat, a receiver coil, and a load coil for powering a medical implant. The magnetically coupled resonance between two isolated parts is established by an array of primary coils and a single small secondary coil to create a transcutaneous power link for implanted devices as moving targets. The primary isolated part includes a driver coil array magnetically coupled to a mat of hexagonally packed primary coils. Power is injected by the driver coils into the transmitter coils in the transmitter mat to maintain resonance in the presence of losses and power drawn by the receiver coil from the magnetic field. The implanted secondary isolated part includes a receiver coil magnetically coupled to a load coil. A rectification/filter system is connected to the load coil supplying DC power to the electronic circuits of the implant.

Claims

1. A resonance-based wireless power transfer system, comprising:

a) a load;

b) a drive coil array, said drive coil array comprising a number of driver coils, said driver coils injecting RF energy to maintain resonance in the presence of losses and power drawn by the load;

c) a transmitter coil array, said transmitter coil array comprising a number of transmitter coils magnetically coupled to said driver coil array, said transmitter coils having at least one resonant frequency and acting as an energy transmitter;

d) a receiver coil, said receiver coil having at least one resonant frequency, capturing magnetic field produced by said transmitter coil array, and acting as an energy receiver; and

e) a load coil, said load coil being magnetically coupled to said receiver coil for receiving RF energy;

wherein;

said transmitter coil array and said receiver coil have the same resonant frequency or frequencies, each pair of said driver coil and said transmitter coil forms a voltage step-up transformer to produce a strong resonance for wireless power delivery to said receiver coil within a body, and said load coil is operatively coupled to power said load;

said receiver coil is hollow and comprises two end covers and a side wall;

said two end covers are connected to each other via said side wall;

an inner cavity is formed inside said receiver coil by said two end covers and said side wall;

each of said two end covers is a planar spiral coil;

said side wall is a helical coil; and

said load coil is placed inside said inner cavity and is magnetically coupled to said receiver coil.

2. The system of claim 1, wherein

said transmitter coils are hexagonally packed to form a transmitter mat;

said transmitter coils are grouped into standard hexagonal cells;

each of said standard hexagonal cells comprises seven transmitter coils constructed by hexagonal PCBs (printed circuit board); and

said transmitter mat generates uniform magnetic field for free-access wireless electricity via magnetically resonant coupling between said transmitter mat and said receiver coil as a moving target.

3. The system of claim 2, wherein each of said standard hexagonal cells is individually driven.

4. The system of claim 2, wherein a target position tracking device is used to determine which of said standard hexagonal cells or which of said transmitter coils are to transmit power.

5. The system of claim 2, wherein a second plurality of planar spiral coils are constructed in a front side by said hexagonal PCBs, several conductor strips on a reverse side of each of said hexagonal PCBs are utilized to form distributed capacitances with respect to said second plurality of planar spiral coils on the front side.

6. The system of claim 5, wherein each of said conductor strips covers only two adjacent tracks of said second plurality of planar spiral coils, and each of said PCBs comprises a plurality of conductive strips to form distributed capacitances.

7. The system of claim 2, wherein said transmitter coil is a circular spiral.

8. The system of claim 2, wherein said transmitter coil is a square or rectangular spiral.

9. The system of claim 2, wherein said transmitter coil is a fan-shape spiral.

10. The system of claim 2, wherein conductor coils and/or conductive strips have a large surface area thereof plated with silver to provide for small electric resistance adapting to the skin effect of RF current.

11. The system of claim 1, wherein

said driver coil array comprises a number of hexagonal elements, each element consisting of seven loops;

said seven loops are all connected in parallel to a pair of open coaxial conductor rings which are further connected to the output of an RF power amplifier; and

a gap is made at each ring to avoid harmful loop current generated by an RF magnetic field.

12. The system of claim 11, wherein said elements are individually activated.

13. The system of claim 1, wherein the exterior of said receiver coil is coated or covered by a biocompatible material.

14. The system of claim 1, wherein said receiver coil is cylindrical in shape in order to comply with exterior dimensions of an associated (parent) device that is cylindrical or circular in shape.

15. The system of claim 1, wherein said receiver coil takes on a rectangular shape in order to correspond to associated devices of rectangular shape.

16. The system of claim 1, wherein said planar spiral coil is circular, rectangular, or hexagonal.