SYSTEM AND METHOD OF DETERMINING AN ENERGY HARVESTING CAPABILITY OF A LOCATION

• US 20110264293A1
• Filed: 04/27/2010
• Published: 10/27/2011
• Est. Priority Date: 04/27/2010
• Status: Abandoned Application

• Current Assignee: EnOcean GmbH
• Original Assignee: EnOcean GmbH
• Inventors: Burke, David M., Forrest, Earl David
• Application Number:
  US12/767,877
• Publication Number:
  US 20110264293A1
• Time in Patent Office: Days
• US Class Current: 700/295
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/35 with light sensitive cells

Abstract

A method of determining an energy harvesting capability of a location harvests energy at a location using an energy harvester and charges an energy storage device using the harvested energy. The energy storage device is discharged into a test circuit to provide a notification. The steps of charging the energy storage device and discharging the energy storage device are selectively repeated such that the notification is provided at a rate proportional to an amount of energy being harvested at the location.

Claims

1. A method of determining an energy harvesting capability of a location, comprising:

harvesting energy at a location using an energy harvester;

charging an energy storage device using the harvested energy;

discharging the energy storage device into a test circuit to provide a notification; and

selectively repeating said steps of charging the energy storage device and discharging the energy storage device such that the notification is provided at a rate proportional to an amount of energy being harvested at the location.

2. The method of claim 1, including:

comparing the notification rate to a desired notification rate, the desired notification rate indicating an amount of energy being harvested that is sufficient to power a selected load; and

moving the energy harvester to another location and in response to the notification rate being less than a desired notification rate.

3. The method of claim 1, including:

comparing the notification rate to a desired notification rate, the desired notification rate indicating an amount of energy being harvested that is sufficient to power a selected load; and

disconnecting the energy storage device from the test circuit and connecting the energy harvester to the load in response to the notification rate being greater than or equal to a desired notification rate.

4. The method of claim 1, wherein said step of harvesting energy at a location using an energy harvester includes using at least one photovoltaic cell to harvest solar energy, and wherein the energy storage device includes at least one capacitor.

5. The method of claim 1, wherein said step of discharging the energy storage device to provide a notification includes:

connecting the energy storage device to a plurality of resistors configured to exhibit a hysteresis effect voltage threshold; and

connecting the energy storage device and the plurality of resistors to a comparator; and

turning ON the comparator output to pass current through a notification device to provide the notification in response to a charge of the energy storage device exceeding the hysteresis effect voltage threshold.

6. The method of claim 5, wherein the notification device includes at least one light-emitting diode.

7. A circuit for determining an energy harvesting capability of a location, comprising:

an energy harvester operable to harvest energy from environmental conditions at a location; and

a notification device operable to provide a notification at a rate proportional to an amount of energy being harvested by the energy harvester at the location.

8. The circuit of claim 7, including:

an energy storage device connected to the energy harvester and operable to be charged by the energy harvester;

a plurality of resistors connected to the energy storage device and configured to exhibit a hysteresis effect voltage threshold; and

a comparator operable to turn ON to provide current to the notification device in response to a charge of the energy storage device exceeding the hysteresis effect voltage threshold.

9. The circuit of claim 8, including:

a load, wherein the energy harvester is connected to the energy storage device in a first, test mode, and wherein the energy harvester is disconnected from the energy storage device and is connected to the load in a second, operational mode in response to the notification rate being greater than or equal to a desired notification rate.

10. The circuit of claim 7, wherein the energy harvester includes at least one photovoltaic cell operable to harvest solar energy.

11. A method of determining an energy harvesting capability of a location, comprising:

connecting an energy harvester to a first energy storage device in a test mode, a system load not being powered in the test mode;

charging the first energy storage device using energy harvested by the energy harvester at a location;

comparing a charge of the first energy storage device to a desired charge;

providing a notification to indicate the result of the comparison; and

disconnecting the first energy storage device from the energy harvester and connecting the energy harvester to a second energy storage device in an operational mode in response to the capacitor charge being greater than or equal to a desired charge, wherein the second energy storage device has a greater energy storage capacity than the first storage device, and wherein in the operational mode the system load is powered by the energy harvester via the second energy storage device.

12. The method of claim 11, including:

A) relocating the energy harvester to another location in response to the notification indicating that capacitor charge rate is less than the desired charge;

B) repeating said steps of charging the first energy storage device using energy harvested by the energy harvester and comparing a charge of the first energy storage device to a desired charge; and

C) selectively repeating steps (A)-(B) until the notification indicates that the capacitor charge is greater than or equal to the desired charge.

13. The method of claim 11, wherein said providing a notification to indicate the result of the comparison includes:

illuminating at least one first light-emitting diode having a first color in response to the capacitor charge being greater than or equal to the desired charge; and

illuminating at least one second light-emitting diode having a second color different from the first color in response to the capacitor charge being less than the desired charge.

14. The method of claim 11, wherein said providing a notification to indicate the result of the comparison includes:

providing a notification at a rate proportional to an amount of energy being harvested at the location.

15. The method of claim 11, wherein said step of charging the first energy storage device using energy harvested by the energy harvester at a location includes using at least one photovoltaic cell to harvest solar energy.

16. A circuit for determining an energy harvesting capability of a location, comprising:

an energy harvester operable to harvest energy from environmental conditions;

a first energy storage device being charged by the energy storage device in a test mode;

a second energy storage device being charged by the energy storage device in an operational mode, the second energy storage device having an energy storage capacity that is greater than an energy storage capacity of the first energy storage device;

at least one notification device operable to provide a notification if a charge of the first energy storage device is greater than or equal to a desired charge;

a system load being powered by the energy harvester via the second energy storage device in the operational mode, and not being powered in the test mode; and

a switch operable to change between the test mode and the operational mode by connecting or disconnecting the energy storage devices from the energy harvester.

17. The circuit of claim 16, including:

at least one comparator; and

at least one plurality of resistors configured to exhibit a hysteresis effect, wherein the at least one comparator and the at least one plurality of resistors compare the charge of the first energy storage device to the desired charge, and turn ON a comparator output to command the at least one notification device to provide the notification in response to the capacitor charge being greater than or equal to the desired charge.

18. The circuit of claim 16, wherein each of the first and second energy storage devices includes at least one capacitor.

19. The circuit of claim 16, wherein the notification device includes at least one light-emitting diode operable to provide a first notification if a charge of the first energy storage device is less than a desired charge, and operable to provide a second notification if a charge of the first energy storage device is greater than or equal to the desired charge.

20. The circuit of claim 16, including a microcontroller operable to control the notification device, wherein the microcontroller is operable to command the notification device to provide a first notification if a charge of the first energy storage device is sufficient to power only the microcontroller, and wherein the microcontroller is operable to command the notification device to provide a second notification if a charge of the first energy storage device is sufficient to power both the microcontroller and the system load.