LOW POWER CONVERSION AND MANAGEMENT OF ENERGY HARVESTING APPLICATIONS

• US 20110254514A1
• Filed: 03/25/2011
• Published: 10/20/2011
• Est. Priority Date: 04/05/2010
• Status: Active Grant

• Current Assignee: Amped Components, LLC
• Original Assignee: Luna Innovations, Inc.
• Inventors: FLEMING, Jerry W.
• Granted Patent: US 9,276,463 B2
• Time in Patent Office: Days
• US Class Current: 320/166
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: H02M 3/07 using capacitors charged and discharged alternately by semiconductor devices with control electrode , e.g. charge pumps
• CPC Class Codes: H02M 3/158 including plural semiconductor devices as final control devices for a single load
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

A method and apparatus for low voltage conversion and energy storage uses a charge pump array including a first set of capacitors in parallel with a second set of capacitors and switches for selectively coupling the first and second set of capacitors to a variable input DC voltage. A data processor programmably controls one or more of the switches to couple the first and second set of capacitors to the variable input DC voltage for a variable first time period during which the input DC voltage charges the first and second set of capacitors to a DC voltage level. An energy storage device is switchably coupled to an output of the charge pump array. The data processor programmably controls one or more of the switches to couple the charge pump array output to the energy storage device for a variable second time period during which a voltage stored across each of the capacitors during the first time period is combined to produce a higher voltage significantly higher than the input DC voltage, the higher voltage being provided to the energy storage device.

Claims

1. Apparatus for low voltage conversion and energy storage, comprising:

a charge pump array including a first set of capacitors in parallel with a second set of capacitors and switches for selectively coupling the first and second set of capacitors to a variable input DC voltage;

a data processor configured to programmably control one or more of the switches to couple the first and second set of capacitors to the variable input DC voltage for a variable first time period during which the input DC voltage charges the first and second set of capacitors to a DC voltage level;

an energy storage device switchably coupled to an output of the charge pump array,

wherein the data processor is configured to programmably control one or more of the switches to couple the charge pump array output to the energy storage device for a variable second time period during which a voltage stored across each of the capacitors during the first time period is combined to produce a higher voltage significantly higher than the input DC voltage, the higher voltage being provided to the energy storage device.

2. The apparatus in claim 1, wherein the higher voltage is at least twice as large as the input DC voltage.

3. The apparatus in claim 1, wherein the variable input DC voltage is provided by a low voltage generator, and wherein the data processor is configured to match an impedance of at least the charge pump array to an impedance of the low voltage generator.

4. The apparatus in claim 3, wherein the data processor is configured to detect a current impedance of the low voltage generator and vary the first and second variable time periods based on the detected current impedance of the low voltage generator so as to match the impedance of at least the charge pump array to the detected current impedance of the low voltage generator.

5. The apparatus in claim 4, wherein the data processor is configured to vary the first and second variable time periods by toggling switch control signals used to control switches in the charge pump array.

6. The apparatus in claim 1, wherein the first and second groups of capacitors each includes multiple capacitors connected in series.

7. The apparatus in claim 1 coupled to a load which draws on energy from the energy storage device.

8. The apparatus in claim 1, further comprising energy storage device circuitry configured to protect the energy storage device from electrical faults.

9. The apparatus in claim 1 coupled to an energy harvesting device for generating the variable input DC voltage, wherein the energy harvesting device produces energy inconsistently.

10. The apparatus in claim 9, wherein the energy harvesting device includes any one of the following:

a thermoelectric generator, a photovoltaic device, a mechanical vibration harvesting device, and a radio frequency harvesting device.

11. The apparatus in claim 1, further comprising step down switch circuitry coupled to the energy storage device for providing a stepped-down voltage to the data processor.

12. The apparatus in claim 1, wherein the data processor is programmed to operate in multiple modes including a normal mode and a low power mode, and wherein the data processor is configured to enter the low power mode when the variable input DC voltage is less than a predetermined minimum level.

13. The apparatus in claim 12, wherein the data processor is programmed to operate in a brownout mode, and wherein the data processor is configured to enter the brownout mode when the variable input DC voltage is less than a previously stored value of the variable input DC voltage.

14. The apparatus in claim 1, wherein the data processor is programmed to control a timing and/or duration of the first and second variable time periods.

15. The apparatus claim 1, wherein conversion of the input DC voltage to the higher output voltage is achieved using the apparatus with an efficiency of 90% or higher.

16. The apparatus in claim 1, wherein the input voltage is on the order of 20 millivolts and the current is on the order of tenths of amps, and wherein the output voltage is on the order of tenths of volts to over one volt.

17. A method for low voltage conversion and energy storage using a charge pump array including a first set of capacitors in parallel with a second set of capacitors and switches for selectively coupling the first and second set of capacitors to a variable input DC voltage, the method comprising:

a controller controlling one or more of the switches to couple the first and second set of capacitors to the variable input DC voltage for a variable first time period during which the input DC voltage charges the first and second set of capacitors to a DC voltage level, and

the controller controlling one or more of the switches to couple the charge pump array output to an energy storage device switchably coupled to an output of the charge pump array for a variable second time period during which a voltage stored across each of the capacitors during the first time period is combined to produce a higher voltage significantly higher than the input DC voltage, the higher voltage being provided to the energy storage device.

18. The method in claim 17, wherein the variable input DC voltage is provided by a low voltage generator, and wherein the method further comprises matching an impedance of at least the charge pump array to an impedance of the low voltage generator.

19. The method in claim 18, further comprising detecting a current impedance of the low voltage generator and varying the first and second variable time periods based on the detected current impedance of the low voltage generator so as to match the impedance of at least the charge pump array to the detected current impedance of the low voltage generator.

20. The method in claim 17, further comprising controlling a timing and/or duration of the first and second variable time periods.