System and method for monitoring photovoltaic power generation systems

• US 8,204,709 B2
• Filed: 01/17/2006
• Issued: 06/19/2012
• Est. Priority Date: 01/18/2005
• Status: Expired due to Fees

• Current Assignee: Solar Sentry Corp.
• Original Assignee: Solar Sentry Corp.
• Inventors: Presher, Gordon E. Jr., Warren, Carlton J.
• Primary Examiner(s): BHAT, ADITYA S
• Application Number:
  US11/333,005
• Publication Number:
  US 20060162772A1
• Time in Patent Office: 2,345 Days
• Field of Search: 702/182
• US Class Current: 702/88
• CPC Class Codes: H01L 31/02021 for solar cells electrical connection means, e.g. junction boxes, specially adapted for structural association with photovoltaic modules H02S40/34
• CPC Class Codes: H02J 7/35 with light sensitive cells
• CPC Class Codes: H02S 50/10 Testing of PV devices, e.g. of PV modules or single PV cells testing of semiconductor devices during manufacturing H01L22/00
• CPC Class Codes: Y02E 10/56 Power conversion systems, e.g. maximum power point trackers

Abstract

A system and method for monitoring photovoltaic power generation systems or arrays, both on a local (site) level and from a central location. The system includes panel and string combiner sentries or intelligent devices, in bidirectional communication with a master device on the site to facilitate installation and troubleshooting of faults in the array, including performance monitoring and diagnostic data collection.

Claims

1. A panel sentry in proximity, electrically connected to, and monitoring both a photovoltaic panel and an adjacent electrical device wherein the panel sentry and the photovoltaic panel, in combination, and the adjacent electrical device are within a series string of electrical devices, each having compatible interface and operating characteristics, said panel sentry comprising:

a source of power;

a first circuit for detecting a voltage of the photovoltaic panel and producing a first signal representing the voltage of the photovoltaic panel;

a second circuit for producing a second signal representing the voltage of the adjacent electrical device in the series string;

an electrical conductor serially connecting a power terminal of the photovoltaic panel directly to a power terminal of the opposite polarity of the adjacent electrical device in the series string;

a second electrical conductor, connected to provide a communication channel between the panel sentry and photovoltaic panel combination and the adjacent electrical device, said second conductor carrying a signal indicating a measured voltage of the adjacent electrical device;

a serial communication device for communicating information to the adjacent electrical device in the series string using at least said second electrical conductor; and

a transmitter for transmitting at least the first and second signals to at least one external device, said transmitter being powered by the source of power.

2. The panel sentry of claim 1, wherein the first circuit and the second circuit each include a voltage detector, detecting a voltage and producing, respectively, a first signal and a second signal, each representing the respective voltage.

3. The panel sentry of claim 2, further comprising a microcontroller connected to and powered by the source of power, and in bidirectional communication with an external device, the microcontroller being connected to the first and second voltage detectors and receiving the first and second signals therefrom and controlling the transmitter to transmit at least the first and second signals to the external device.

4. The panel sentry of claim 3, further comprising a memory storing at least a digital representation of the first signal.

5. The panel sentry of claim 4, further comprising memory storing a physical location for at least the first photovoltaic panel, including an electrical position within a string connected to a specific combiner.

6. The panel sentry of claim 3 further comprising an indicating device and a receiver for receiving at least one signal from at least one external device, and wherein the operation of the indicating device is responsive to the received signal.

7. The panel sentry of claim 1 further comprising at least one indicating device displaying real-time status for the panel.

8. The panel sentry of claim 1 wherein the source of power includes the photovoltaic panel.

9. The panel sentry of claim 1 wherein the source of power includes a battery.

10. The panel sentry of claim 1 wherein the adjacent electrical device includes a second photovoltaic panel and where the source of power includes the adjacent panel.

11. The panel sentry of claim 1 further comprising a wired connection between the microcontroller and the adjacent electrical device in the series string.

12. The panel sentry of claim 1 further comprising a wireless transceiver electrically connected to the microcontroller and in bi-directional communication with at least one external device.

13. The panel sentry of claim 1 wherein the source of power includes a capacitive storage device.

14. The panel sentry of claim 1 wherein the adjacent electrical device includes a second photovoltaic panel and where the source of power includes, in the alternative, the current panel and the adjacent electrical device.

15. A panel sentry in proximity, electrically connected to, and monitoring both a photovoltaic panel and an adjacent electrical device wherein the panel sentry and the photovoltaic panel, in combination, and the adjacent electrical device are within a series string of electrical devices, each having compatible interface and operating characteristics, said panel sentry comprising:

a source of power;

a first panel voltage detector detecting a first voltage produced by the first panel and producing a first signal representing the first voltage;

a second voltage detector detecting a second voltage produced by the adjacent electrical device and producing a second signal representing the voltage of the adjacent electrical device;

a bi-directional communication channel with an at least one external device;

a microcontroller, powered by the source of power, in bi-directional communication via said bi-directional communication channel with the external device, said microcontroller being electrically connected to the first panel voltage detector and the second voltage detector, and receiving the first signal from the first voltage detector and the second signal from the second voltage detector, and transmitting the first signal and the second signal to the external device; and

a memory storing a digital representation of the first signal and the second signal.

16. The panel sentry of claim 15 further comprising a junction box cover such that at least, the first panel voltage detector, the microcontroller and the memory are mounted in the junction box cover.

17. The panel sentry of claim 15 further comprising a second photovoltaic panel voltage detector, the second photovoltaic panel voltage detector detecting a second voltage produced by a second photovoltaic panel and producing a second signal representing the second voltage, the second detector electrically connected to the microcontroller, the memory storing a digital representation of the second signal.

18. The panel sentry of claim 17 further comprising a digital representation of information relative to the configuration of the second panel, stored in the memory.

19. The panel sentry of claim 17 such that, the second voltage detector comprises an analog to digital converter.

20. The panel sentry of claim 15 further comprising an indicating device.

21. The panel sentry of claim 15 wherein the source of power includes the photovoltaic panel.

22. The panel sentry of claim 15 wherein the source of power includes a battery.

23. The panel sentry of claim 15 wherein the source of power includes a second photovoltaic panel.

24. The panel sentry of claim 15 further comprising a wired connection between the microcontroller and the adjacent electrical device in the series string.

25. The panel sentry of claim 15 further comprising a wireless transceiver electrically connected to the microcontroller and in bi-directional communication with at least one external device.

26. The panel sentry of claim 15 further comprising a digital representation of information relative to the configuration of the panel sentry stored in the memory.

27. The panel sentry of claim 15 further comprising a digital representation of information relative to the configuration of the first panel, stored in the memory.

28. The panel sentry of claim 15 wherein the first voltage detector comprises an analog to digital converter.

29. The panel sentry of claim 15 further comprising a digital representation of an average voltage of the first panel during an update period, the average computed by the microcontroller, the average stored in the memory.

30. The panel sentry of claim 15, further comprising non-volatile memory storing a physical location for at least the first photovoltaic panel, including an electrical position within a string connected to a specific combiner.

31. The panel sentry of claim 15, wherein said panel sentry is attached to the photovoltaic panel.

32. A string sentry for monitoring at least one string of photovoltaic panels comprising:

a source of power;

a current detector detecting the total current produced by the string of photovoltaic panels and producing a signal representing the total current;

a microcontroller, powered by the source of power, in bi-directional communication with an external device and electrically connected to the current detector and electrically connected to the source of power, the microcontroller receiving the signal from the current detector and transmitting the signal to the external device, said microcontroller further receiving signals indicative of a voltage for at least a first photovoltaic panel and an adjacent photovoltaic panel, where said first and adjacent panels are within the string of photovoltaic panels; and

a memory storing a digital representation of the signal representing the current and representation of the voltage for the first photovoltaic panel and the adjacent photovoltaic panel.

33. The string sentry of claim 32 further comprising a wired connection between the microcontroller and the external device.

34. The string sentry of claim 32 further comprising a wireless transceiver electrically connected to the microcontroller and in bi-directional communication with an external device.

35. The string sentry of claim 32 further comprising a digital representation of information relative to the configuration of the string sentry stored in the memory.

36. The string sentry of claim 32 further comprising a digital representation of information relative to the configuration of a photovoltaic array stored in the memory.

37. The string sentry of claim 32 further comprising a digital representation of information relative to the configuration of a string combiner stored in the memory.

38. The string sentry of claim 32 wherein the current detector comprises an analog to digital converter.

39. The string sentry of claim 32 further comprising:

a string voltage detector, the string voltage detector detecting the voltage of a string of photovoltaic panels and producing a string signal representing the string voltage, the string voltage detector electrically connected to the microcontroller, the microcontroller receiving the string signal and transmitting a value representing the string signal to the external device, the memory storing a digital representation of the signal representing the string voltage.

40. The string sentry of claim 39 wherein the string voltage detector comprises an analog to digital converter.

41. The string sentry of claim 39 further comprising, a combined voltage detector, the combined voltage detector detecting the combined voltage of at least one string of photovoltaic panels and producing a combined signal representing the combined voltage, the combined voltage detector electrically connected to the microcontroller, the microcontroller receiving the combined signal and transmitting a value representing the combined signal to the external device, the memory storing a digital representation of the signal representing the combined voltage.

42. The string sentry of claim 32 further comprising:

a combined voltage detector, the combined voltage detector detecting the combined voltage of at least one string of photovoltaic panels and producing a combined signal representing the combined voltage, the combined voltage detector electrically connected to the microcontroller, the microcontroller receiving the combined signal and transmitting a value representing the combined signal to the external device, the memory storing a digital representation of the signal representing the combined voltage.

43. The string sentry of claim 42 wherein the combined voltage detector comprises an analog to digital converter.

44. The string sentry of claim 32 further comprising:

a string combiner having the current detector, the microcontroller and the memory installed therein.

45. The string sentry of claim 44 further comprising a digital representation of information relative to the configuration of the string combiner stored in the memory.

46. The string sentry of claim 32 wherein the source of power includes a string of photovoltaic panels.

47. The string sentry of claim 32 wherein the source of power includes a battery.

48. The string sentry of claim 32 further comprising a visual signaling device.

49. The string sentry of claim 32, wherein said microcontroller tests the voltage value for the adjacent panel against a threshold to determine if a panel fault exists.

50. The string sentry of claim 32, wherein said microcontroller tests the voltage value for the adjacent panel against a threshold to determine if a string fault exists.

51. The string sentry of claim 32, wherein said memory includes non-volatile memory.

52. A method for monitoring at least one string of photovoltaic panels comprising:

collecting, using a string sentry, an average value of a current from a string of photovoltaic panels;

storing, in the string sentry, the average value of the current of the string of photovoltaic panels;

transmitting the average value of the current from the string sentry to an external computer;

using a string voltage detector, separated by at least a fuse from the combined string voltage, to detect the voltage of the string of photovoltaic panels, and producing a string signal representing the string voltage,

storing a digital representation of the signal representing the string voltage in the string sentry; and

transmitting a value representing the string voltage signal to the external computer, the memory, wherein the external computer compares the received string voltage signal value against at least one other string voltage signal value to detect whether said fuse is open.

53. The method of claim 52 further comprising:

collecting, using the string sentry, average voltage information from a panel sentry;

storing, in the string sentry, the average voltage value from the panel sentry; and

transmitting the average voltage value from the string sentry to the external computer.

54. The method of claim 52 further comprising:

collecting, using the string sentry, a real-time voltage value from a panel sentry;

storing, in the string sentry, the real-time voltage value of the panel sentry; and

transmitting the real-time voltage value from the string sentry to the external computer.

55. The method of claim 54, further comprising using the average voltage from the panel sentry to determine if a panel sentry fault exists in the panel.

56. The method of claim 55, further comprising:

collecting, using the string sentry, an instantaneous voltage value for an adjacent panel (Vnxt) from a panel sentry;

storing, in the string sentry, the instantaneous voltage value for the adjacent panel; and

testing the instantaneous voltage value for the adjacent panel against a threshold to determine if a panel fault exists.

57. The method of claim 52 further comprising:

collecting, using the string sentry, configuration information from a panel sentry;

storing, in the string sentry, configuration information of the panel sentry; and

transmitting the configuration information from the string sentry to the external computer.

58. The method of claim 52 further comprising:

collecting, using a string sentry, string average voltage information from at least one string of photovoltaic panels;

storing, in a string sentry, the string instantaneous voltage value of at least one string of photovoltaic panels; and

transmitting the string instantaneous voltage value from a string sentry to the external computer.