Data acquisition apparatus and methodology for self-diagnosing of AC modules
First Claim
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1. A power generating system comprising:
- a first array of two or more solar cell modules, each module comprising an inverter and a photovoltaic (PV) laminate, said PV laminate including a plurality of electrically interconnected solar cells for generating a DC power output, and said inverter electrically connected to said PV laminate for converting said DC power output to an AC power output;
an AC power bus extending between said modules and connected to said inverter of each module for collecting the AC power output of said first array of modules; and
a junction box electrically connected to said AC power bus;
wherein said inverter is configured to;
sense selected parameters from the group consisting of DC voltage, DC current, AC voltage, AC current, cumulative energy, inverter temperature, PV laminate temperature, and solar cell temperature;
digitize said sensed parameters, andtransmit sensed parameters data over said AC power bus to said junction box; and
wherein said junction box is configured to;
receive and store sensed parameters data transmitted by said inverters over said AC power bus;
analyze said stored parameters data on a module basis and an array basis and store the results of the analysis; and
transmit said digitized sensed parameters data and/or the results of said analysis to a remote receiver.
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Abstract
Method and apparatus for monitoring, measuring and recording the operating values of each of a plurality of inter-connected AC PV modules and performing a diagnostic analysis, including comparing the those operating values to each other and to operating values recorded at an earlier time to determine laminate degradation and the performance-attenuating effect of temperature, soiling, shading, and snow cover on the modules.
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Citations
35 Claims
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1. A power generating system comprising:
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a first array of two or more solar cell modules, each module comprising an inverter and a photovoltaic (PV) laminate, said PV laminate including a plurality of electrically interconnected solar cells for generating a DC power output, and said inverter electrically connected to said PV laminate for converting said DC power output to an AC power output; an AC power bus extending between said modules and connected to said inverter of each module for collecting the AC power output of said first array of modules; and a junction box electrically connected to said AC power bus; wherein said inverter is configured to; sense selected parameters from the group consisting of DC voltage, DC current, AC voltage, AC current, cumulative energy, inverter temperature, PV laminate temperature, and solar cell temperature; digitize said sensed parameters, and transmit sensed parameters data over said AC power bus to said junction box; and wherein said junction box is configured to; receive and store sensed parameters data transmitted by said inverters over said AC power bus; analyze said stored parameters data on a module basis and an array basis and store the results of the analysis; and transmit said digitized sensed parameters data and/or the results of said analysis to a remote receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A method for acquiring operating and environmental data from an array of photovoltaic (PV) modules, each module including a power output section and a dedicated inverter connected to the power output section, said method comprising:
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(a) operating each inverter to convert a DC output of the module to which it is dedicated to an AC output, measuring the current and voltage values of said DC and AC outputs, the inverter temperature, and the temperature of a PV laminate component of the module, converting the measured values and temperatures to digital data, and storing said digital data in said inverter; (b) providing said AC output from each inverter to a common AC power output bus for delivery to a load; (c) transmitting said stored digital data from said inverter to a computer controlled datalogger over said common AC power bus aided by an AC filter designed to eliminate interference of said digital data by AC grid noise; (d) selectively evaluating, by the datalogger, the stored digital data from each inverter to determine inverter DC faults, AC faults, and internal faults and storing the results of the evaluation; and (e) selectively evaluating, by the datalogger, the stored digital data from each module to determine module faults resulting from one or more of the following;
snow accumulation, shading of module, soiling of module front face, high module temperature, and non-uniform orientation of modules in the array, and storing the results of the evaluation. - View Dependent Claims (20, 21)
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22. A photovoltaic power generating apparatus comprising:
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a plurality of PV modules clustered together in an array, each of said modules comprising; a PV laminate that converts solar energy to a DC power output; an inverter electrically connected to the PV laminate and structured to convert the DC power output of said connected PV laminate to an AC power output, and an AC power bus connected to said inverters for combining the AC power outputs of said inverters; wherein each inverter comprises; a microprocessor for controlling operation of said inverter and for converting current values of the DC power output and the AC power output to power output data of each inverter in digital form; a memory device for storing said power output data, inverter temperature data representing a temperature of each inverter, and laminate temperature data representing a temperature of the PV laminate to which each inverter is connected; and a transmitting device for transmitting said power output data, said inverter temperature data, and said laminate temperature data over said power bus; and a datalogger configured to; receive the transmitted data via said power bus; store the transmitted data; compare the transmitted data to data received at an earlier time; determine inverter and module faults on the basis of the comparison; store the results of the comparison; and transmit the data and the stored results to a separate data collection device. - View Dependent Claims (23)
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24. A method for acquiring operating and environmental data from a cluster of PV modules where each module is configured to generate a DC power output in response to received solar radiation, said method comprising the following steps:
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(a) converting the DC power output of each PV module individually to an AC power output using a separate dedicated inverter for each PV module; (b) collecting the AC power output of all of the modules in said cluster via a common AC power bus; (c) for each PV module, measuring a voltage, an electric current, and energy values of the DC and AC power outputs, a current temperature of the PV module, and a current temperature of its dedicated inverter; (d) storing the measured values and said temperatures for each PV module in the form of digital format data at the site of said PV module; (e) transmitting said digital format data from the PV modules of said cluster to a cluster data collection point; (f) storing said digital format data from all of said PV modules at said cluster data collection point; (g) at said cluster data collection point, evaluating said digital format data to determine faults occurring in step (a); (h) at said cluster data collection point, comparing said digital format data from each PV module with the digital format data of the other PV modules in the cluster, and comparing said digital format data with like digital format data derived from said PV modules at a previous time to evaluate individual and relative performance of the modules in the cluster to determine event-caused performance faults; and (i) recording all of said faults. - View Dependent Claims (25, 26, 27, 28, 29)
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30. A method for acquiring operating and environmental data from a cluster of n AC PV modules, where n is a number greater than 1 and each module is configured to generate a DC power output in response to received solar radiation and includes a dedicated inverter for converting said DC power output to an AC power output, said method comprising the following steps:
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(a) converting the DC power output of each PV module to an AC power output using the dedicated inverter for said each AC PV module; (b) for each AC PV module, measuring a voltage, an electric current, and energy values of said DC and AC power outputs, a current temperature of said each AC PV module, and a current temperature of its dedicated inverter; (c) storing said values and said temperatures for each AC PV module in the form of digital format data at the site of said AC PV module; (d) evaluating said digital format data of all of said n AC PV modules on a module by module basis to determine faults occurring in step (a); (e) comparing said digital format data of said AC PV modules to determine those AC PV modules that fail to meet a predetermined power output level; (f) comparing said digital format data of those AC PV modules that fail to meet said predetermined power output level with like digital format data derived from those AC PV modules at a previous time to determine and characterize event-caused performance faults; and (g) recording data indicative of all of said faults in memory. - View Dependent Claims (31, 32, 33, 34, 35)
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Specification