System and method for autonomous adaptive cleaning of PV panels based on high level control signals

Patent metadata

Field	Value
Publication number	US-9584064-B2
Application number	US-201213648369-A
Country	US
Kind code	B2
Filing date	Oct 10, 2012
Priority date	Oct 10, 2012
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

A solar energy system and method of cleaning photovoltaic panels is provided. Measurements relating to weather at a photovoltaic panel are received by the system. Measurements relating to output current and voltage at the photovoltaic panel are received by the system. Expected power of the photovoltaic panel is determined based on the measurements relating to weather. Actual power of the photovoltaic panel is determined based on the measurements relating to output current and voltage. In response to determining that the actual power is not within a predetermined range of the expected power (e.g. at least one photovoltaic panel is dirty), a cleaning of the photovoltaic panel is initiated.

First claim

The invention claimed is:

1. A method of cleaning photovoltaic panels in a solar energy system, the method comprising:
receiving pyranometer measurements relating to weather conditions at a photovoltaic panel;
receiving measurements relating to output current and voltage at the photovoltaic panel;
determining expected power of the photovoltaic panel based on the measurements relating to weather conditions;
determining actual power of the photovoltaic panel based on the measurements relating to output current and voltage;
in response to determining that the actual power is not within a predetermined range of the expected power, initiating a cleaning of the photovoltaic panel; and
updating a data log with a location of the cleaning, a time stamp of the cleaning and a number of cleaning cycles, wherein if the number of cleaning cycles exceeds a threshold limit comprising a number of cleaning cycles within a time period, updating the data log to recommend a manual inspection of the photovoltaic panel.

2. The method of cleaning photovoltaic panels in a solar energy system of claim 1 , wherein if the threshold limit has been reached, disabling future cleanings of the photovoltaic panel.

3. The method of cleaning photovoltaic panels in a solar energy system of claim 1 , wherein the measurements relating to weather conditions comprise measurements relating to at least one of irradiance, temperature, wind speed, shading, and clouding.

4. The method of cleaning photovoltaic panels in a solar energy system of claim 1 , further comprising:
prior to the step of initiating a cleaning of the photovoltaic panel: waiting a period of time after the step of determining actual power of the photovoltaic panel;
receiving second measurements relating to weather conditions at the photovoltaic panel after waiting the period of time;
receiving second measurements relating to output current and voltage at the photovoltaic panel after waiting the period of time;
determining second expected power of the photovoltaic panel based on the second measurements relating to weather conditions;
determining second actual power of the photovoltaic panel based on the second measurements relating to the output current and voltage; and
determining that the second actual power is not within the predetermined range of the second expected power.

5. The method of cleaning photovoltaic panels in a solar energy system of claim 1 , wherein the photovoltaic panel comprises a string of photovoltaic panels.

6. A system comprising:
sensors configured to measure weather related conditions, and output current and voltage of a photovoltaic panel, the sensors comprising a pyranometer;
a supervisory controller configured to:
generate a control signal to initiate a cleaning of the photovoltaic panel, the control signal generated based at least on an expected power of the photovoltaic panel based on the measurements relating to weather and an actual power of the photovoltaic panel based on the measurements relating to output current and voltage;
update a data log with a location of the cleaning, a time stamp of the cleaning and a number of cleaning cycles, wherein if the number of cleaning cycles exceeds a threshold limit comprising a number of cleaning cycles within a time period, updating the data log to recommend a manual inspection of the photovoltaic panel; and

a photovoltaic cleaning assembly disposed on an array of photovoltaic panels, the photovoltaic cleaning assembly configured to clean the photovoltaic panel in response to receiving the control signal from the supervisory controller.

7. The system of claim 6 , wherein the supervisory controller is further configured to determine whether the actual power is within a predetermined range of the expected power.

8. The system of claim 6 , wherein the photovoltaic cleaning assembly further comprises a brush assembly comprising at least one of a rotating brush, bristles, nozzles, actuators, a motor and a squeegee.

9. The system of claim 6 , wherein the measurements related conditions comprise measurements relating to at least one of irradiance, temperature, wind speed, shading, and clouding.

10. The system of claim 6 , wherein the photovoltaic panel comprises a string of photovoltaic panels.

11. The system of claim 6 , wherein the sensors comprise at least one of an anemometer, a current sensor, a voltage sensor and a temperature sensor.

12. A non-transitory computer readable medium storing computer program instructions, which when executed on a processor cause the processor to perform a method comprising:
receiving pyranometer measurements relating to weather conditions at a photovoltaic panel;
receiving measurements relating to output current and voltage at the photovoltaic panel;
determining expected power of the photovoltaic panel based on the measurements relating to weather; determining actual power of the photovoltaic panel based on the measurements relating to output current and voltage;
in response to determining that the actual power is not within a predetermined range of the expected power, initiating a cleaning of the photovoltaic panel; and
updating a data log with a location of the cleaning, a time stamp of the cleaning and a number of cleaning cycles, wherein if the number of cleaning cycles exceeds a threshold limit comprising a number of cleaning cycles within a time period, updating the data log to recommend a manual inspection of the photovoltaic panel.

13. The non-transitory computer readable medium of claim 12 , wherein if the threshold limit has been reached, disabling future cleanings of the photovoltaic panel.

14. The non-transitory computer readable medium of claim 12 , wherein the measurements relating to weather conditions comprise measurements relating to at least one of irradiance, temperature, wind speed, shading, and clouding.

15. The non-transitory computer readable medium of claim 12 , further comprising:
prior to the step of initiating a cleaning of the photovoltaic panel:
waiting a period of time after the step of determining actual power of the photovoltaic panel;
receiving second measurements relating to weather conditions at the photovoltaic panel after waiting the period of time;
receiving second measurements relating to output current and voltage at the photovoltaic panel after waiting the period of time;
determining second expected power of the photovoltaic panel based on the second measurements relating to weather conditions;
determining second actual power of the photovoltaic panel based on the second measurements relating to the output current and voltage; and
determining that the second actual power is not within the predetermined range of the second expected power.

16. The non-transitory computer readable medium of claim 12 , wherein the photovoltaic panel comprises a string of photovoltaic panels.

Assignees

• Siemens Ag

Inventors

• Suresh Sindhu
• Weber Anthony
• Patre Parag

Classifications

• F24J2/461

  Mechanical Engineering · mapped topic

• A46B13/02

  power-driven {carriers} · CPC title

• H02S40/10 Primary

  Cleaning arrangements · CPC title

• Y02E10/50

  Photovoltaic [PV] energy · CPC title

• F24S40/20

  Cleaning; Removing snow · CPC title