Resonant, contactless radio frequency power coupling

• US 8,212,414 B2
• Filed: 05/29/2009
• Issued: 07/03/2012
• Est. Priority Date: 07/10/2008
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Howard, Robert James, Rapp, John W., Soonachan, Stanley
• Primary Examiner(s): KAPLAN, HAL IRA
• Application Number:
  US12/474,376
• Publication Number:
  US 20100007214A1
• Time in Patent Office: 1,131 Days
• Field of Search: 307/104
• US Class Current: 307/104
• CPC Class Codes: B60L 2200/32 Waterborne vessels
• CPC Class Codes: B60L 53/122 Circuits or methods for driving the primary coil, e.g. supplying electric power to the coil
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 Information or communication technologies improving the operation of electric vehicles

Abstract

A resonant, contactless, RF power coupling suitable for high power-density applications and for use in an ocean environment is disclosed. In the illustrative embodiment, the power coupling includes a transmit coupling and a receive coupling, each of which include a resonant element. A high-powered RF generator is coupled to the transmit coupling and a rectifier circuit is coupled to the output coupling. Each of the resonant elements is disposed in its own electrically-conductive canister and advantageously potted in an appropriate insulating dielectric. Each canister has an open end to facilitate inductive coupling between the two resonant elements. In order to exclude seawater from the interface between the canisters, a seal of compliant material is disposed therebetween.

Claims

1. A contactless RF power coupling system comprising:

a transmit coupling, wherein the transmit coupling includes a first canister that is electrically conductive and at least partially open at an end thereof, and a first resonant circuit having a first resonant frequency;

a receive coupling, wherein the receive coupling includes a second canister that is electrically conductive and at least partially open at an end thereof, and a second resonant circuit having a second resonant frequency; and

an RF source that provides the RF signal to the transmit couplings, the RF source comprising;

a direct current power supply;

a plurality of switches, wherein each of the plurality of switches comprises a first contact and a second contact, and wherein each of the plurality of first contacts and the power supply are electrically connected at a first node, and wherein each of the plurality of second contacts and the first resonant circuit are electrically connected at a second node; and

a controller, wherein the controller controls the state of each of the plurality of switches;

wherein the transmit coupling receives an RF signal having a first frequency and a second frequency that is a harmonic frequency of the first frequency, and wherein the transmit coupling passes each of the first frequency and second frequency to the receive coupling when the transmit coupling and receive coupling are inductively coupled.

2. The RF power coupling system of claim 1 wherein the first resonant frequency and the second resonant frequency are equal.

3. The RF power coupling system of claim 1 wherein at least one of the first resonant frequency and second resonant frequency is tunable.

4. The RF power coupling system of claim 1 further comprising a seal, wherein the first canister has a first end that is open and the second canister has a second end that is open, and wherein the first canister couples with the second canister such that the first end and second end are opposed, and wherein the seal is interposed between the first end and second end, and further wherein the seal:

(a) comprises a compliant material; and

(b) is shaped to force fluid out of the first canister and the second canister.

5. The RF power coupling system of claim 4 wherein the seal has a shape that is relatively wider near a midpoint thereof and relatively narrower near an end thereof.

6. The RF power coupling system of claim 4 wherein the seal has the shape of a biconvex lens.

7. A method for contactless coupling of RF power to a storage system, wherein the method comprises:

providing an RF signal to a first coupling, wherein the first coupling comprises a first resonant circuit having a first resonant frequency, and wherein the RF signal comprises a first frequency and a second frequency that is a harmonic frequency of the first frequency;

locating a second coupling at a first distance from the first coupling, wherein the second coupling comprises a second resonant circuit having a second resonant frequency, and wherein the first distance enables inductive coupling of the RF signal between the first coupling and the second coupling;

forming a seal between the first coupling and the second coupling, wherein the seal is formed by compressing a compliant member between the first coupling and the second coupling, wherein the compliant member has a shape that is relatively wider near a midpoint thereof and relatively narrower near an end thereof, and wherein the compression of the compliant member forces fluid out of at least one of the first coupling and the second coupling; and

coupling the RF signal between the first coupling and the second coupling, wherein the coupled RF signal contains each of the first frequency and the second frequency.

8. The method of claim 7 further comprising conveying electrical energy based on the RF signal from the second coupling to a storage system.

9. The method of claim 7 further comprising generating the RF signal, wherein the RF signal is generated by operations comprising:

providing a direct current electrical signal to a switch bank having an input and an output, wherein the switch bank comprises a plurality of switches that are electrically connected in parallel, and wherein the output and the first coupling are electrically connected; and

controlling the position of each of the switches.

10. The method of claim 7 further comprising controlling at least one of the first resonant frequency and the second resonant frequency.

11. The method of claim 7 further comprising monitoring an impedance of the first coupling.

12. A contactless, RF power coupling system comprising:

a transmit coupling, wherein the transmit coupling includes;

(a) a first canister that is electrically conductive and at least partially open at an end thereof; and

(b) a first resonant circuit disposed in the first canister;

a receive coupling, wherein the receive coupling includes;

(a) a second canister that is electrically conductive and at least partially open at an end thereof; and

(b) a second resonant circuit disposed in the second canister, wherein, the first and second canister are disposed with respect to one another so that the partially open end of each of the first and second canisters are in opposed relation; and

an RF source, wherein the RF source and the transmit coupling are electrically connected, and wherein the RF source provides an RF signal that comprises a first frequency and a second frequency that is a harmonic frequency of the first frequency;

wherein the transmit coupling passes each of the first frequency and second frequency to the receive coupling when the transmit coupling and receive coupling are inductively coupled.

13. The RF power coupling system of claim 12 wherein the second frequency is an odd harmonic of the first frequency.

14. The RF power coupling system of claim 12 further comprising a seal, wherein the seal is interposed between the opposed partially open ends of the first and second canister, and further wherein the seal:

(a) comprises a compliant material; and

(b) is shaped to force water out of the first canister and the second canister.

15. The RF power coupling of claim 14 wherein the seal forms a watertight seal for each of the transmit coupling and receive coupling when compressed between the transmit coupling and the receive coupling.

16. The RF power coupling of claim 14 wherein the seal has the shape of a biconvex lens.

17. The RF power coupling of claim 12 wherein the first resonant circuit comprises a helical resonator.

18. The RF power coupling of claim 12 wherein the transmit coupling and receive coupling are detachably mountable to one another, and wherein when the transmit coupling and receive coupling are mounted to one another:

(a) the transmit coupling and receive coupling are disposed with respect to one another so that the RF signal is coupled between the first resonant circuit and the second resonant circuit; and

(b) the first resonant circuit and the second resonant circuit are separated by less than 6 inches.

19. A power transfer system comprising:

a first coupling, wherein the first coupling includes a first resonant circuit having a first resonant frequency;

a second coupling, wherein the second coupling includes a second resonant circuit having a second resonant frequency;

a first storage system, wherein the first storage system stores electrical energy that is based on a first signal received from the second coupling; and

a seal, wherein the seal is interposed between a first canister of the first coupling and a second canister of the second coupling, and wherein the seal comprises a compliant material and is shaped to force water out of the first canister and the second canister;

wherein the first coupling receives a first RF signal having a first frequency and a second frequency that is a harmonic frequency of the first frequency, and wherein the first coupling passes each of the first frequency and second frequency to the second coupling when the first coupling and second coupling are inductively coupled; and

wherein the first storage system stores electrical energy that is based on the first signal, and further wherein the first signal is based on the first RF signal.

20. The power transfer system of claim 19 further comprising:

an RF generator; and

a third coupling that has a third resonant circuit having a third resonant frequency;

wherein the RF generator generates a second RF signal having a third frequency, and wherein the second coupling passes the third frequency to the third coupling when the second coupling and third coupling are inductively coupled.

21. The power transfer system of claim 20 further comprising a vehicle, wherein the vehicle comprises the second coupling, the first storage system, and the third coupling.

22. The power transfer system of claim 20 wherein the second RF signal further comprises a fourth frequency that is a harmonic of the third frequency, and wherein the second coupling passes the fourth frequency to the third coupling when the second coupling and third coupling are inductively coupled.

23. The power transfer system of claim 22 wherein the fourth frequency is an odd harmonic of the third frequency.

24. The power transfer system of claim 19 wherein the seal forms a substantially watertight seal for each of the third coupling and fourth coupling when compressed between the third coupling and the fourth coupling.

25. A power transfer system comprising:

a first coupling, wherein the first coupling includes a first resonant circuit having a first resonant frequency;

a second coupling, wherein the second coupling includes a second resonant circuit having a second resonant frequency;

a first storage system;

an RF generator; and

a switch, wherein the switch has a first position and a second position, and wherein the second coupling and the storage system are electrically connected when the switch is in the first position, and wherein the second coupling and the RF generator are electrically connected when the switch is in the second position

wherein the first coupling passes each of a first frequency and a second frequency of a first RF signal to the second coupling when the first coupling and second coupling are inductively coupled and the switch is in the first position, and wherein the second frequency is a harmonic of the first frequency; and

wherein the second coupling passes each of a third frequency and a fourth frequency of a second RF signal to the first coupling when the first coupling and second coupling are inductively coupled and the switch is in the second position, and wherein the fourth frequency is a harmonic of the third frequency.

26. The power transfer system of claim 25 further comprising an impedance detector, wherein the switch has a third position, and wherein the second coupling and the impedance detector are electrically connected with the switch is in the third position.

27. A power transfer system comprising:

a first coupling, wherein the first coupling includes a first resonant circuit having a first resonant frequency;

a second coupling, wherein the second coupling includes a second resonant circuit having a second resonant frequency;

a third coupling, wherein the third coupling includes a third resonant circuit having a third resonant frequency;

a fourth coupling, wherein the fourth coupling includes a fourth resonant circuit having a fourth resonant frequency;

a rectifier; and

an RF generator;

wherein the first coupling passes each of a first frequency and a second frequency of a first RF signal to the second coupling when the first coupling and second coupling are inductively coupled;

wherein the rectifier receives the first RF signal from the second coupling and converts the first RF signal into a first DC signal;

wherein the RF generator receives the first DC signal and converts it into a second RF signal; and

wherein the third coupling receives the second RF signal from the RF generator.