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US 8,239,149 B2Granted
Method for determining the operating condition of a photovoltaic panel
AssigneeArray Power, Inc.
InventorsMika Nuotio, Kent Kernahan
Life of this patent
Estimating the term…
Abstract
Due to their exposure to extreme environments, it is expected that parts or all of a solar power system will experience degradation in performance. The degradation may be due to temporary environmental factors, such as cloud cover; damage or localized soiling; a general dirty condition; or ageing of the components. A method is disclosed wherein a remote system may detect degraded performance and determine the cause, thereby enabling a decision as to the appropriate corrective action to be taken, if any.
Claims44
A method for determining the operating condition of a solar panel, wherein the solar panel is controlled by an electronic module, comprising the steps of:
- measuring a temperature of the solar panel;
- determining the instant maximum power condition of the solar panel;
- selecting a condition of voltage and a condition of current that correspond to the instant maximum power point condition;
- controlling the solar panel to provide the selected condition of voltage and condition of current;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- and
- determining the cause of the variance from the model according to a rule,
- wherein the rule determines that a solar panel is shaded if the solar panel is not damaged and further that power production of the solar panel is dissimilar to other nearby solar panels in a solar panel system.
9 more elements
A method for determining the operating condition of a solar panel, wherein the solar panel is controlled by an electronic module, comprising the steps of:
- measuring a temperature of the solar panel;
- determining the instant maximum power condition of the solar panel;
- selecting a condition of voltage and a condition of current that correspond to the instant maximum power point condition;
- controlling the solar panel to provide the selected condition of voltage and condition of current;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel, wherein the previously determined values for series and shunt resistances are the values determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- determining the cause of the variance from the model according to a rule,
- wherein the previously determined series resistance is determined by the steps comprising:
- increasing the output current value (Is) of the solar panel;
- measuring the voltage output value (Vs) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vs−Vmp)/(Is−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition.
13 more elements
A method for determining the operating condition of a solar panel, wherein the solar panel is controlled by an electronic module, comprising the steps of:
- measuring a temperature of the solar panel;
- determining the instant maximum power condition of the solar panel;
- selecting a condition of voltage and a condition of current that correspond to the instant maximum power point condition;
- controlling the solar panel to provide the selected condition of voltage and condition of current;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel, wherein the previously determined values for series and shunt resistances are the values determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- determining the cause of the variance from the model according to a rule,
- wherein the previously determined shunt resistance is determined by the steps comprising:
- decreasing the output current value (Ish) of the solar panel;
- measuring the voltage output value (Vsh) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vsh−Vmp)/(Ish−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition.
13 more elements
An electronic module configured to determine the operating condition of a solar panel, comprising:
- a processor;
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- and
- determining a cause of the variance from the model according to a rule,
- wherein the rule determines that the solar panel is shaded if the solar panel is not damaged and further that power production of the solar panel is dissimilar to other nearby solar panels in a solar panel system.
13 more elements
An electronic module configured to determine the operating condition of a solar panel, comprising:
- a processor;
- a non-volatile memory coupled to the processor;
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel stored in the non-volatile memory that were determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- determining a cause of the variance from the model according to a rule;
- increasing the output current value (Is) of the solar panel;
- measuring the voltage output value (Vs) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vs−Vmp)/(Is−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition;
- and
- storing the calculated impedance in the memory for use in the model as previously determined series resistance in subsequent measuring cycles.
19 more elements
An electronic module configured to determine the operating condition of a solar panel, comprising:
- a processor;
- a non-volatile memory coupled to the processor;
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel stored in the non-volatile memory that were determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, taking the additional steps of:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- determining a cause of the variance from the model according to a rule;
- decreasing the output current value (Ish) of the solar panel;
- measuring the voltage output value (Vsh) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vsh−Vmp)/(Ish−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition;
- and
- storing the calculated impedance in the memory for use in the model as previously determined shunt resistance in subsequent measuring cycles.
19 more elements
A solar panel system, comprising:
- a solar panel;
- and
- an electronic module configured to determine the operating condition of the solar panel, comprising:
- a processor;
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, perform further operations comprising:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- and
- determining a cause of the variance from the model according to a rule,
- wherein the rule determines that a solar panel is shaded if the solar panel is not damaged and further that power production of the solar panel is dissimilar to other nearby solar panels in a solar panel system.
16 more elements
A solar panel system, comprising:
- a solar panel;
- and
- an electronic module configured to determine the operating condition of the solar panel, comprising:
- a processor;
- a non-volatile memory coupled to the processor
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel stored in the non-volatile memory that were determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, perform further operations comprising:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- and
- determining a cause of the variance from the model according to a rule;
- increasing the output current value (Is) of the solar panel;
- measuring the voltage output value (Vs) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vs−Vmp)/(Is−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition;
- and
- storing the calculated impedance in the non-volatile memory for use in the model as previously determined series resistance in subsequent measuring cycles.
23 more elements
A solar panel system, comprising:
- a solar panel;
- and
- an electronic module configured to determine the operating condition of the solar panel, comprising:
- a processor;
- a non-volatile memory coupled to the processor
- a temperature sensing circuit coupled to the processor and configured for measuring the temperature of the solar panel;
- a voltage sensing circuit coupled to the processor;
- and
- a current sensing circuit coupled to the processor,
- wherein the processor is configured with processor-executable instructions to perform operations comprising:
- receiving a measured temperature of the solar panel;
- determining an instant maximum power condition of the solar panel;
- comparing the instant maximum power condition to a model based upon the temperature and previously determined values for series and shunt resistances of the solar panel stored in the non-volatile memory that were determined in a previous measuring cycle;
- and
- if the instant maximum power condition varies from the model by more than a predetermined value, perform further operations comprising:
- determining the instant series resistance of the solar panel;
- determining the instant shunt resistance of the solar panel;
- and
- determining a cause of the variance from the model according to a rule;
- decreasing the output current value (Ish) of the solar panel;
- measuring the voltage output value (Vsh) of the solar panel;
- calculating an impedance using the formula
- impedance=(Vsh−Vmp)/(Ish−Imp),
- wherein Vmp is the voltage value for the maximum power condition and Imp is the current value for the maximum power condition;
- and
- storing the calculated impedance in the non-volatile memory for use in the model as previously determined shunt resistance in subsequent measuring cycles.
23 more elements
Dependencies are inferred from the claim text.