Lighting system with induction power supply

• US 10,284,021 B2
• Filed: 08/14/2018
• Issued: 05/07/2019
• Est. Priority Date: 08/14/2017
• Status: Active Grant

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Kisner, Roger A., Johnson, Christi R., Reed, Frederick K.
• Primary Examiner(s): Vu, Jimmy T
• Application Number:
  US16/103,324
• Publication Number:
  US 20190052125A1
• Time in Patent Office: 266 Days
• Field of Search: 315149-158, 315200 R, 315209 R, 315291, 315307, 315308
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/30 using light, e.g. lasers
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/37 Converter circuits
• CPC Class Codes: H05B 47/105 in response to determined parameters
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/16 by timing means
• CPC Class Codes: H05B 6/06 Control, e.g. of temperature, of power
• CPC Class Codes: H05B 6/10 Induction heating apparatus, other than furnaces, for specific applications
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A system for producing light is provided. The system comprises a sealed enclosure surrounding a porous graphite foam conductor which is exposed to an electromagnetic field generated by an oscillating circuit. When exposed, the foam conductor conducts induced electric current which heats the same to product light. The amount of light is controllable by changing the output of a drive circuit. The oscillating circuit comprises a first inductor and a first capacitor. The first inductor has a first terminal and a second terminal. The output of the drive circuit is controlled by turning a MOSFET OFF and ON. The MOSFET is turned ON when an integrated signal representative of a difference between a voltage proportional to the first terminal and a voltage proportional to the second terminal is between a first voltage threshold and a second voltage threshold and based on a timing signal.

Claims

1. A system for producing light comprising:

a sealed enclosure surrounding a porous graphite foam conductor;

an oscillating circuit comprising a first inductor and a first capacitor, the first inductor having a first terminal and a second terminal, the oscillating circuit configured to generate an electromagnetic field, the porous graphite foam conductor when exposed to the electromagnetic field conducting an induced electric current, the induced electric current heating the porous graphite foam conductor to produce light;

a drive circuit couplable to an AC power source and the oscillating circuit, the drive circuit configured to regulate an amount of light produced by the porous graphite foam conductor, the drive circuit comprising;

a full wave rectifier couplable to the AC power source configured to convert AC power from the AC power source into DC power; and

a MOSFET, the drain of the MOSFET being coupled to the second terminal, the source coupled to a ground and the gate being coupled to a gate drive circuit, the MOSFET being turned on when an integrated signal representative of a difference between a voltage proportional to the first terminal and a voltage proportional to the second terminal is between a first voltage threshold and a second voltage threshold and based on a timing signal.

2. The system of claim 1, further comprising a light sensor configured to detect the light produced by the porous graphite foam conductor or a temperature sensor configured to detect the temperature of the porous graphite foam conductor.

3. The system of claim 2, wherein at least one the first voltage threshold and the second voltage threshold are variable to increase or decrease the light produced based on the detected light by the light sensor or the temperature detected by the temperature sensor.

4. The system of claim 3, wherein the first voltage threshold and the second voltage threshold are respectively varied by adjusting a respective potentiometer.

5. The system of claim 2, wherein the timing signal is variable to increase or decrease the light produced based on the detected light by the light sensor or the temperature detected by the temperature sensor.

6. The system of claim 5, further comprising a 555 timing circuit configured to output the timing signal based on input to a trigger pin and a threshold pin, the input to the trigger pin and the threshold pin being variable using a potentiometer.

7. The system of claim 1, further comprising an insulator at least partially surrounding the sealed enclosure, wherein the insulator is disposed between the sealed enclosure and the first inductor.

8. The system of claim 7, wherein the insulator has a window and the light is emitted via the window.

9. The system of claim 8, further comprising a reflector disposed opposing the window where the light is emitted.

10. The system of claim 1, wherein the first inductor is a spiral coil, and wherein the system further comprises an insulator disposed between the porous graphite foam conductor and the spiral coil and a reflector disposed between the porous graphite foam conductor and the spiral coil, the reflector comprising a plurality of reflective portions separated by gaps.

11. The system of claim 1, wherein at least a portion of the light is emitted in the infrared spectrum.

12. The system of claim 1, wherein the drive circuit further comprises a decoupling device between the full wave rectifier and the oscillating circuit.

13. The system of claim 12, wherein the decoupling device is a diode coupled in series with a second inductor, where the second inductor is coupled to the first terminal.

14. The system of claim 13, further comprising a second capacitor having a first plate and a second plate, the first plate being coupled to the second inductor and the first terminal of the inductor and the second plate being coupled to the ground.

15. The system of claim 13, further comprising:

a first resistor coupled to a second resistor in series, the first resistor coupled to the first terminal, wherein the voltage proportional to the first terminal is a voltage between the first resistor and the second resistor; and

a third resistor coupled to a fourth resistor in series, the third resistor coupled to the second terminal, wherein the voltage proportional to the second terminal is a voltage between the third resistor and the fourth resistor.

16. The system of claim 15, wherein the first resistor has a different resistance than the third resistor.

17. The system of claim 1, wherein the electromagnetic field is controllable to a power less than 100 W.

18. The system of claim 1, further comprising an ambient light sensor configured to sense light in an environment where the system is deployed and wherein at least one of the first voltage threshold and the second voltage threshold are variable to increase or decrease the light produced based on the detected light by the ambient light sensor.

19. The system of claim 18, wherein the timing signal is variable to increase or decrease the light produced based on the detected light by the ambient light sensor.

20. The system of claim 1, wherein the sealed enclosure further comprises a noble gas.