Off-grid led street lighting system with multiple panel-storage matching

• US 20110084646A1
• Filed: 10/14/2010
• Published: 04/14/2011
• Est. Priority Date: 10/14/2009
• Status: Abandoned Application

• Current Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Original Assignee: National Semiconductor Corporation (Texas Instruments, Inc.)
• Inventors: Lisi, Gianpaolo, Djabbari, Ali
• Application Number:
  US12/925,110
• Publication Number:
  US 20110084646A1
• Time in Patent Office: Days
• US Class Current: 320/101
• CPC Class Codes: H02J 7/0071 with a programmable schedule
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A system includes multiple photovoltaic panels having a combined output profile that defines energy or power generated by the photovoltaic panels over time. Each photovoltaic panel is configured to generate a peak amount of energy or power at a different time. The system also includes a storage device having a charging profile and configured to be charged by the photovoltaic panels. The charging profile defines a maximum amount of energy or power sinkable by the storage device at a given time. The output profile and the charging profile are substantially matched such that a maximum level of the output profile is approximately equal to the maximum amount of energy or power sinkable by the storage device. The maximum level of the output profile could be substantially constant over time between first and second peak amounts of energy or power generated by different photovoltaic panels.

Claims

1. A system comprising:

multiple photovoltaic panels having a combined output profile that defines energy or power generated by the photovoltaic panels over time, each photovoltaic panel configured to generate a peak amount of energy or power at a different time; and

a storage device having a charging profile and configured to be charged by the photovoltaic panels, the charging profile defining a maximum amount of energy or power sinkable by the storage device at a given time;

wherein the output profile and the charging profile are substantially matched such that a maximum level of the output profile is approximately equal to the maximum amount of energy or power sinkable by the storage device.

2. The system of claim 1, wherein the maximum level of the output profile is substantially constant over time between a first peak amount of energy or power generated by one of the photovoltaic panels and a second peak amount of energy or power generated by another of the photovoltaic panels.

3. The system of claim 1, wherein the photovoltaic panels are angled with respect to one another in order to maximize a total amount of energy or power generated during a specified time period.

4. The system of claim 3, wherein one or more angles for the photovoltaic panels are based on a location of the photovoltaic panels.

5. The system of claim 1, further comprising:

a maximum power point tracking (MPPT) unit configured to perform maximum power point tracking for the multiple photovoltaic panels; and

a charge controller configured to control charging of the storage device by the photovoltaic panels.

6. The system of claim 1, further comprising:

a power converter configured to convert power received from the storage device; and

one or more light emitting diodes configured to generate light using the converted power.

7. The system of claim 1, wherein the storage device comprises a battery bank.

8. An apparatus comprising:

a maximum power point tracking (MPPT) unit configured to perform maximum power point tracking for multiple photovoltaic panels;

a storage device configured to be charged by the photovoltaic panels, the storage device having a charging profile defining a maximum amount of energy or power sinkable by the storage device at a given time; and

a charge controller configured to control charging of the storage device by the photovoltaic panels;

wherein the charging profile is substantially matched to an output profile of the photovoltaic panels that defines energy or power generated by the photovoltaic panels over time and that is based on multiple peak amounts of energy or power generated by different photovoltaic panels at different times, the charging profile substantially matched to the output profile such that a maximum level of the output profile is approximately equal to the maximum amount of energy or power sinkable by the storage device.

9. The apparatus of claim 8, wherein the maximum level of the output profile is substantially constant over time between a first peak amount of energy or power generated by one of the photovoltaic panels and a second peak amount of energy or power generated by another of the photovoltaic panels.

10. The apparatus of claim 8, further comprising:

a power converter configured to convert power received from the storage device.

11. The apparatus of claim 10, further comprising:

one or more light emitting diodes configured to generate light using the converted power.

12. The apparatus of claim 10, wherein the power converter comprises a direct current-to-direct current converter.

13. The apparatus of claim 8, wherein the charging profile is substantially matched to the output profile of the photovoltaic panels so that substantially all of the energy or power generated by the photovoltaic panels is stored in the storage device.

14. The apparatus of claim 8, wherein the storage device comprises a battery bank.

15. A method comprising:

performing maximum power point tracking for multiple photovoltaic panels, the photovoltaic panels having a combined output profile that defines energy or power generated by the photovoltaic panels over time, each photovoltaic panel generating a peak amount of energy or power at a different time; and

charging a storage device using the photovoltaic panels, the storage device having a charging profile defining a maximum amount of energy or power sinkable by the storage device at a given time;

wherein the output profile and the charging profile are substantially matched such that a maximum level of the output profile is approximately equal to the maximum amount of energy or power sinkable by the storage device.

16. The method of claim 15, further comprising:

generating light using one or more light emitting diodes that operate using power from the storage device.

17. The method of claim 15, wherein the maximum level of the output profile is substantially constant over time between a first peak amount of energy or power generated by one of the photovoltaic panels and a second peak amount of energy or power generated by another of the photovoltaic panels.

18. The method of claim 15, wherein the photovoltaic panels are angled with respect to one another in order to maximize a total amount of energy or power generated during a specified time period.

19. The method of claim 18, wherein one or more angles for the photovoltaic panels are based on a location of the photovoltaic panels.

20. The method of claim 15, further comprising:

performing maximum power point tracking for the multiple photovoltaic panels.