Soiling detection apparatus and method

专利摘要:
A soiling detection apparatus (20) operable to detect a soiling level of a photovoltaic panel (22). The apparatus comprising a photovoltaic panel (22) operable to generate an electrical output in response to light being incident on the panel and in dependence upon a soiling level of the photovoltaic panel. The apparatus comprises a pyranometer (24) operable to generate an irradiance signal which relates to an irradiance level of light incident on the pyranometer (24). The pyranometer (24) is positioned with respect to the photovoltaic panel (22) such that the photovoltaic panel (22) and the pyranometer (24) can receive substantially the same solar radiation level as each other. The apparatus comprises calculating means operable to calculate a reference output value from the irradiance signal which relates to an ideal electrical output of the photovoltaic panel (22) at a predetermined operating condition. The apparatus further comprises measuring means operable to measure the electrical output of the photovoltaic panel (22) at the predetermined operating condition, and comparing means operable to compare the measured electrical output of the photovoltaic panel (22) at the predetermined operating condition with the reference output value so as to generate a comparison value. The apparatus comprises outputting means operable to output a cleaning signal when the comparison value is greater than a cleaning threshold value.
公开号:ES2787726A2
申请号:ES202090033
申请日:2018-04-09
公开日:2020-10-16
发明作者:Ammar Mohammed Munir Sulayman Alsabounchi
申请人:Dubai Electricity & Water Authority；
IPC主号:

专利说明:

[0002] Dirt detection apparatus and method
[0004] Field of the invention
[0006] The present disclosure relates to a soil detection apparatus and method.
[0008] State of the art
[0010] Solar photovoltaic (PV) installations in arid and desert areas are potentially affected by frequent fouling caused by the precipitation of dust, sand and other suspended particles on the surface of photovoltaic panels. The impact is further aggravated in humid weather, where particles cumulatively stick to the surfaces of photovoltaic panels forming a thick and substantially opaque layer of dirt. The situation turns out to be a serious problem that reduces the efficiency of the photovoltaic plant and, consequently, its profitability.
[0012] For this reason, the operators of the photovoltaic plants can carry out regular cleaning events of the photovoltaic panels with a pre-established frequency, such as monthly or biweekly. However, the actual need for cleaning events is likely to change, for example based on changes in weather conditions. This can adversely affect the optimal performance of pre-programmed cleaning events. For example, a cleaning event can occur or be scheduled when the panels do not need to be cleaned, or it can occur after the panel may actually need cleaning.
[0014] One way to approach this question is to detect the level of dirt on the photovoltaic panels. Then a cleaning event can be organized for when the panel needs to be cleaned, such as a dirt level that reaches a certain dirt threshold. One arrangement to detect the level of dirt is to install two photovoltaic modules. A first photovoltaic module comprising a first photovoltaic panel is positioned so that it is exposed to dirt conditions substantially the same as those experienced by a photovoltaic plant, such as one comprising a plurality of photovoltaic modules. A second photovoltaic module comprising a second photovoltaic panel that is substantially analogous to the first photovoltaic module is positioned so that it receives substantially the same solar radiation as the first module. photovoltaic. The second photovoltaic module is intended to be kept in a clean state so that dirt does not substantially affect its production. The output of the first photovoltaic module and the second photovoltaic module can then be compared to estimate the level of fouling.
[0016] However, to keep the second PV module clean, it may be necessary to perform regular and frequent cleaning. Alternatively, some arrangements use a cover to protect the surface of the second photovoltaic panel from dirt deposits that can be removed automatically or manually when a dirt measurement is to be made. However, those arrangements can be expensive, mechanically complex, and prone to failure.
[0018] The examples in the present disclosure attempt to address or at least alleviate the aforementioned problems.
[0020] Summary of the invention
[0022] In a first aspect, there is provided a dirt detection apparatus operable to detect the dirt level of a photovoltaic panel, the apparatus comprises: a photovoltaic panel operable to generate an electrical output in response to light incident on the panel and on dependence on the level of dirt on the photovoltaic panel; a pyranometer operable to generate an irradiation signal that relates to a level of irradiation of the light incident on the pyranometer, the pyranometer being positioned relative to the photovoltaic panel such that the photovoltaic panel and the pyranometer can receive substantially the same level solar radiation than the other; calculating means operable to calculate a reference production value from the irradiation signal that relates to an ideal electrical production of the photovoltaic panel in a predetermined operating condition; operable measuring means for measuring the electrical production of the photovoltaic panel in the predetermined operating condition; comparison means operable to compare the measured electrical production of the photovoltaic panel in the predetermined operating condition with the reference production value in order to generate a comparison value; and production means operable to produce a cleaning signal when the comparison value is greater than a cleaning threshold value.
[0023] In a second aspect a dirt detection method is provided for detecting the dirt level of a photovoltaic panel using a dirt detection apparatus comprising a photovoltaic panel and a pyranometer positioned relative to the photovoltaic panel so that the photovoltaic panel and the pyranometer can receive substantially the same level of solar radiation as the other, the method comprising: the generation, by the photovoltaic panel, of an electrical production in response to the light that falls on the panel and depending on the level of dirt on the panel photovoltaic; the generation, by the pyranometer, of an irradiation signal that is related to a level of irradiation of the light incident on the pyranometer; calculating a reference production value from the irradiation signal that is related to an ideal electrical output of the photovoltaic panel in a predetermined operating condition; measuring the electrical production of the photovoltaic panel in the predetermined operating condition; comparing the measured electrical production of the photovoltaic panel in the predetermined operating condition with the reference production value in order to generate a comparison value; and emitting a cleaning signal when the comparison value is greater than a cleaning threshold value.
[0025] Other features and features are defined in the appended claims.
[0027] In the exemplary embodiments, a photovoltaic panel and a pyranometer can be used to detect a level of dirt. Using a photovoltaic panel, for example, can reduce costs and improve flexibility and reliability of measurement. Furthermore, the exemplary embodiments can help reduce the need for cleaning or the requirement to use a mechanism to keep a reference photovoltaic panel clean in order for fouling detection to occur. For example, the need to clean the photovoltaic panel of the exemplary embodiments can be reduced because an expected production that may correspond to that which can occur for a substantially clean photovoltaic panel can be predicted from the reference production value calculated from the irradiation as measured by the pyranometer.
[0029] For example, by comparing the measured electrical production of the photovoltaic panel with the reference production value based on the irradiation signal generated by the pyranometer, an indication of the level of dirt can be obtained. If, for example, the comparison value is greater than the cleaning threshold value, then the cleaning signal is output. For example, the cleaning signal may indicate that the photovoltaic panel, and therefore both other photovoltaic panels in a photovoltaic plant where the device is located may need cleaning. Therefore, for example, a cleaning event can be programmed as appropriate depending on the level of dirt detected and therefore the efficiency of cleaning events can be improved, while the need for cleaning a reference photovoltaic panel can be reduced or eliminated. Furthermore, the exemplary embodiments may allow the suitability of a location for a proposed photovoltaic plant to be more easily determined, for example, based on the level of soil measured at that location.
[0031] Description of the figures
[0033] Exemplary embodiments will now be described only with reference to the attached figures, in which like references refer to like parts, and in which:
[0035] Figure 1 is a schematic representation of an arrangement for measuring dirt using two photovoltaic panels.
[0037] Figure 2 is a schematic representation of a dirt detection apparatus according to exemplary embodiments.
[0039] Figure 3 is a schematic circuit diagram of a dirt detection apparatus according to exemplary embodiments.
[0041] Figure 4 is a schematic representation of dirt from a crystalline silicon photovoltaic panel.
[0043] Figure 5 is a schematic representation of dirt on a thin-film photovoltaic panel.
[0045] Figure 6 is a schematic diagram of the pin arrangement of a microcontroller used in the dirt detection apparatus according to exemplary embodiments.
[0046] Figure 7 is a schematic representation of the apparatus for programming the microcontroller of the dirt detection apparatus according to exemplary embodiments.
[0048] Figure 8 is a schematic diagram of a voltage regulation circuit for providing electrical power to the microcontroller according to exemplary embodiments.
[0050] Figure 9 is a schematic diagram of the arrangement of a voltage regulator used in the dirt detection apparatus according to exemplary embodiments.
[0052] Figure 10 is a schematic diagram of the arrangement of the connections of a pyranometer and a shunt resistor used in the dirt detection apparatus according to exemplary embodiments.
[0054] Figure 11 is a schematic diagram of a path of an output signal of the microcontroller used in the dirt detection apparatus according to exemplary embodiments.
[0056] Figure 12 is a schematic circuit diagram of the connection of the voltage regulation circuit to a light sensor used in the dirt detection apparatus according to exemplary embodiments.
[0058] Fig. 13 is a flow chart of a method for detecting the dirt level of a photovoltaic panel using a dirt detecting apparatus according to exemplary embodiments.
[0060] Figures 14A and 14B are a flow chart of a method for detecting the dirt level of a photovoltaic panel by measuring the voltage across the shunt resistor according to exemplary embodiments.
[0062] Detailed description of the invention
[0064] A dirt detecting apparatus and a dirt detecting method are disclosed. Various specific details are presented in the following description so that the exemplary embodiments are well understood. However, it will be apparent to a person skilled in the art that these specific details need not be used to develop the examples. of realization. On the contrary, the specific details known to the person skilled in the art are omitted for the sake of clarity in the presentation of the examples.
[0066] Figure 1 is a schematic representation of an arrangement for measuring dirt using two photovoltaic panels. As mentioned above, a pre-arrangement for detecting fouling may use two photovoltaic panels to detect a level of fouling. The above arrangement comprises a first photovoltaic module 10 and a second photovoltaic module 12. The first photovoltaic module 10 comprises a first photovoltaic panel and the second photovoltaic module 12 comprises a second photovoltaic panel. The first photovoltaic panel is positioned so that it is exposed to soiling conditions substantially the same as those experienced by a photovoltaic plant, such as one comprising a plurality of photovoltaic modules. The second photovoltaic module 12 is substantially analogous to the first photovoltaic module 10 and is positioned so that it receives substantially the same solar radiation as the first photovoltaic module 10. The second photovoltaic module 12 is intended to be kept in a clean state so that dirt does not substantially affect your production. The output of the first photovoltaic module 10 and the second photovoltaic module 12 can then be compared to estimate the level of fouling. However, as mentioned above, to keep the second PV module clean, regular and frequent cleaning may be necessary. Alternatively, some arrangements use a cover to protect the surface of the second photovoltaic module from dirt deposits that can be removed automatically or manually when a dirt measurement is to be made. However, those arrangements can be expensive, mechanically complex, and prone to failure. Also, trying to keep a photovoltaic panel clean all the time in arid desert areas with humid climates can be a difficult task.
[0068] Figure 2 is a schematic representation of a dirt detection apparatus 20 according to exemplary embodiments. In the examples, the dirt detection apparatus 20 operable to detect the dirt level of a photovoltaic panel. In the examples, the apparatus comprises a photovoltaic panel 22 operable to generate an electrical output in response to the light incident on the panel 22 and depending on the level of dirt on the photovoltaic panel 22. In the examples, the photovoltaic panel 22 is a thin film photovoltaic panel. In examples, the photovoltaic panel 22 is a thin-film CdTe photovoltaic panel, a model manufactured by First Solar. However, You appreciate that other types of photovoltaic panel such as a polycrystalline silicon panel can be used.
[0070] In the examples, the apparatus also comprises a pyranometer 24 operable to generate an irradiation signal that is related to an irradiation level of light incident on the pyranometer 24. Pyranometers are commonly used to measure solar irradiance. Typical pyranometers comprise a white metal casing, comprising a glass hemispherical dome under which a black metal absorber is placed so that it can be heated by incident solar radiation on the dome. Typical thermopile pyranometers comprise a thermocouple and to generate a voltage the temperature difference between the absorber and the metal housing is measured. The voltage is generally proportional to the value of the solar irradiation. In other words, for example, the pyranometer can generally work by measuring a heat difference. Therefore, the pyranometer is less likely to need frequent cleaning, as may be the case when an irradiance detector comprising a photovoltaic reference cell is used.
[0072] In the examples, the pyranometer 24 comprises a model CMP10 pyranometer produced by KIPP & ZONEN with a typical output voltage in the range 0-1 V. More generally, in the examples, the pyranometer comprises a thermopile pyranometer. However, it will be appreciated that other suitable pyranometers could be used.
[0074] In the examples, pyranometer 24 is positioned relative to photovoltaic panel 22, such that photovoltaic panel 22 and pyranometer 24 can receive substantially the same level of solar radiation as the other. For example, the photovoltaic panel 22 and the pyranometer 24 may have substantially the same angle and orientation as each other, and be positioned so that they do not mutually occlude the solar radiation when the dirt detection apparatus 20 is deployed in one place. suitable.
[0076] In the examples, the apparatus 20 comprises a base and a support post 28 mounted on the base to be able to support the photovoltaic panel 22 and the pyranometer 24. In the examples, the photovoltaic panel 22 is mounted on the support post 28. In the examples For examples, the support post comprises a post manufactured by Xiamen Sunforson Power Co., Ltd, model number SFS-P-60. In the examples, the photovoltaic panel 22 is mounted on the pole 28 using a photovoltaic bracket, for example, the one manufactured by Xiamen Sunforson Power Co., Ltd, model number SFS-MD-01. However, it will be appreciated that other suitable support posts and photovoltaic supports may be used.
[0078] For example, apparatus 20 comprises an arm 30 that is mounted to support post 28 at a first end 30a of arm 30 so as to extend away from support post 30. In the examples, pyranometer 24 is mounted at a second end 30b of the arm 30 so that it has substantially the same angle and orientation as the photovoltaic panel. In the examples, the apparatus 20 comprises a circuit box 32 mounted on the support post 28 between the base 26 and the photovoltaic panel 22. In the examples , the circuit box 32 houses the circuitry for measuring the soil level of the photovoltaic panel 22, as will be described in more detail below. In the examples, the circuit box 32 comprises a box manufactured by Zhejiang B&J Electrical Co., Ltd. model number 2520/150, and has an IP66 environmental protection level. In the examples, the circuit box 32 has at least an environmental protection level of IP54 in order to protect the circuits from the surrounding environment and help reduce the risk of malfunction. However, it will be appreciated that other suitable boxes may be used to house the circuit of apparatus 20. 22.
[0080] In the examples, the apparatus 20 comprises a circuit housing 32 mounted on the support post 28 between the base 26 and the photovoltaic panel 22. In the examples, the circuit housing 32 houses the circuits for measuring the level of dirt. of the photovoltaic panel 22, as will be described in more detail below. In the examples, the housing for circuit 32 comprises a housing manufactured by Zhejiang B&J Electrical Co., Ltd. model number 2520/150, and has an IP66 environmental protection level. In the examples, the enclosure for circuit 32 has at least an environmental protection level of IP54 in order to protect the circuits from the surrounding environment and help reduce the risk of malfunction. However, it will be appreciated that other suitable housings can be used to house the circuitry of apparatus 20.
[0082] In the examples, the apparatus 20 comprises a battery case 34 mounted to the base 26. In the examples, the battery case 34 houses a battery for supplying power to the output signal circuits of the apparatus 20. In the examples , the battery may also be used to provide power to the measurement circuits of the apparatus 20. In the examples, the battery housing 34 comprises a Snap-Top battery box model number HM318BKS, manufactured by NOCO®, although it will be appreciated that may use other suitable battery boxes. In the examples, the battery housing 34 comprises a deep cycle valve regulated lead acid (VRLA) battery, such as a 12V-26Ah, model DC12-26 manufactured by RITAR. However, it will be appreciated that other batteries can be used.
[0084] In the examples, the apparatus 20 may be placed in a photovoltaic plant comprising a plurality of photovoltaic panels to generate electricity so that it receives substantially the same dirt as one or more photovoltaic panels of the photovoltaic plant. In other words, in the examples, the photovoltaic plant comprises the apparatus 20. In other words, more generally in the examples, the photovoltaic plant comprises a plurality of photovoltaic panels for generating electricity, and the dirt detection apparatus 20, wherein the floor detection apparatus is positioned relative to one or more photovoltaic panels of the photovoltaic plant so that it receives substantially the same dirt as one or more photovoltaic panels of the photovoltaic plant. In this way, the apparatus 20 can help indicate whether the photovoltaic panels of the photovoltaic plant need to be cleaned.
[0086] In the examples, the apparatus 20 can also be used as a stand-alone unit, for example, to assess the suitability of a possible site for a photovoltaic plant.
[0088] Fig. 3 is a schematic circuit diagram of the dirt detection apparatus 20 according to the exemplary embodiments. In the examples, the dirt detection apparatus 20 comprises a dirt detection circuit for measuring the level of dirt on the photovoltaic panel 22.
[0090] In the examples, the dirt detection circuit may act as an operable calculation means to calculate an ideal production value of the photovoltaic panel in a predetermined operating condition. In the examples, the dirt detection circuit may act as an operable comparison means to measure the electrical production of the photovoltaic panel in the predetermined operating condition. In the examples, the dirt detection circuits may act as operable comparison means to compare the measured electrical production of the photovoltaic panel in the predetermined operating condition with the reference production value to generate a comparison value. In the examples, the dirt detection circuit can act as production means operable to produce a cleaning signal when the comparison value is greater than a cleaning threshold value.
[0092] For example, the soil detecting apparatus and the disclosed method can help provide a more reliable indication of the soil level. Furthermore, for example, the need for regular cleaning of the dirt detection apparatus or the need for complex apparatus that help to keep a reference photovoltaic panel in a clean state can be reduced, because the pyranometer may be less affected by dirt than a photovoltaic panel because the irradiance measurement is based on a thermal measurement, for example.
[0094] Thus, for example, the reference output value calculated from the irradiation signal may be related to an ideal operating condition of the photovoltaic panel 22, such as whether the panel is clean. In other words, for example, the reference output value is related to a predicted electrical output value for the photovoltaic panel in a substantially clean state. By comparing, for example, the measured electrical production of the photovoltaic panel 22 in the predetermined operating condition with the reference output value, an indication of the dirt level of the photovoltaic panel 22 can be obtained, for example, based on the comparison value. If, for example, the comparison value is greater than a cleaning threshold value, then the apparatus can output a cleaning signal. In the examples, the cleaning signal indicates that the photovoltaic panel needs to be cleaned, although it could indicate other conditions, such as the estimated future period of time after which the photovoltaic panel needs to be cleaned. In the examples, the cleaning signal refers to a dirt level of the photovoltaic panel 22. Therefore, for example, the need to execute preset cleaning events of inefficient frequency can also be reduced because the cleaning signal can be output when the comparison value is greater than the cleaning threshold value. Furthermore, for example, the photovoltaic panel 22 may not need to be cleaned unless the photovoltaic panels of the photovoltaic plant are cleaned. The apparatus 20 can, for example, also help to determine if there is a malfunction of the photovoltaic plant. For example, if the output of the photovoltaic plant is below a malfunction threshold and the comparison value is less than the value of the cleaning threshold then a malfunction signal of the photovoltaic plant may be output.
[0095] In the examples, the ground detection circuit comprises the photovoltaic panel 22, the pyranometer 24, a microcontroller 36, a shunt resistor 38, a voltage regulator 40, a charge controller 42, a light sensor 44, a battery 46, a first relay 48, a second relay 50, a third relay 52, a fourth relay 54, and a switch 56. In the examples, the microcontroller 36, the shunt resistor 38, the voltage regulator 40, the charge controller 42, first relay 48, second relay 50, third relay 52, fourth relay 54, and switch 56 are housed within circuit housing 32. However, it will be appreciated that other arrangements may be used to accommodate one or more more circuit components.
[0097] The operation of the dirt detection circuits will be described in more detail later.
[0099] In the examples, the first relay 48, the second relay 50, the third relay 52, and the fourth relay 54 are operatively connected to the output pins (O / P) of the microcontroller 36 in order to be in electrical communication with the microcontroller. 36. In the examples, the second relay 50, the third relay 52, and the fourth relay 54 are single pole, unipolar relays. However, it will be appreciated that other types of relays may be used as appropriate. In the examples, the second relay 50, the third relay 52, and the fourth relay 54 are used to provide a plurality of output signals that relate to a fouling level of the photovoltaic panel 22. In the examples, the output signals comprise a first output signal 50a, a second output signal 52a, and a third output signal 54a respectively through a current path 57 of the battery 46.
[0101] In the examples, voltage regulator 40, switch 56, and light sensor 44 are operatively connected to microcontroller 36 to be able to provide electrical power to microcontroller 36. In examples, microcontroller 36 comprises internal memory, although You will appreciate that an external memory can be used. In the examples, the photovoltaic is operatively connected to the input pins (I / P) of the microcontroller 36 through the shunt resistor 38 and the first relay 48 in order to be in electrical communication with the microcontroller 36. In the examples, photovoltaic panel 22 is operatively connected to battery 46 via charge controller 42 and first relay 48 to be able to charge battery 46, for example, when dirt detection is not to be performed. In the examples, the pyranometer 24 is coupled operatively to the input pins (I / P) of the microcontroller 36 through the first relay 48 to be able to be in electrical communication with the microcontroller 36. In the examples, the first relay 48 is a double pole, bipolar relay. As mentioned above, the operation of the dirt detection circuit components will be described in more detail later.
[0103] Figure 4 is a schematic representation of soil on a crystalline silicon photovoltaic panel, and Figure 5 is a schematic representation of soil on a thin-film photovoltaic panel. In particular, Figure 4 schematically shows a crystalline silicon photovoltaic panel 58 comprising a plurality of crystalline silicon photovoltaic cells (such as photovoltaic cells 60a, 60b, 60c and 60d). Figure 4 schematically shows a dirt patch 62 that occludes two cells. For example, dirt or shadows may block an entire area of one or more of the photovoltaic cells in the photovoltaic panel 58, such as the dirt patch 62. This can mean that any cell that is connected in series with those occluded by dirt patch 62 can be overridden. For example, these cells can generate little or no electrical current and can be considered totally or partially out of service depending on the level of dirt. Therefore, using the crystalline silicon photovoltaic panel as a reference to detect the level of dirt can give inaccurate results.
[0105] Figure 5 schematically shows an example of the photovoltaic panel 22. As mentioned above, in the examples, the photovoltaic panel 22 comprises a thin-film photovoltaic panel. Compared to crystalline silicon photovoltaic panels, thin-film photovoltaic panels usually comprise a plurality of photovoltaic cells (such as photovoltaic cells 63a, 63b, 63c, 63d), each of which is formed as a narrow strip, for example, extending the entire length of the panel from one side to the other. In other words, more generally in the examples, the photovoltaic panel 22 comprises a plurality of thin-film photovoltaic cells. In figure 5 a dirt patch 64 is shown schematically in a substantially identical position with respect to panel 22 that dirt patch 62 has with respect to crystalline silicon panel 58. In the example of figure 5, the dirt patch 64 is substantially the same shape and size as the dirt patch 62 illustrated in Figure 4. However, as the cells of the photovoltaic panel 22 of the examples extend substantially along the entire length of the panel from side to side , the risk of an entire area of one or more cells becoming occluded by a dirt patch, such as dirt patch 64. Therefore, the use of a thin-film photovoltaic panel can help improve the reliability and accuracy of dirt measurements.
[0107] Figure 6 is a schematic diagram of the pin arrangement of a microcontroller used in the dirt detection apparatus according to the examples of the disclosure. In particular, Figure 6 shows a pin arrangement of the microcontroller 36. In the examples, the microcontroller 36 comprises an 8-bit microcontroller model Atmega32 40 Pin PDIP, produced by Atmel Corporation. However, it will be appreciated that other microcontrollers can be used. Pins 33 to 40 refer to analog to digital converters. Pin 10 VDC, pin 11 GND and pin 31 GND can be used to provide power to the microcontroller, for example from a 5 volt power supply. AVCC pin 30 can also be connected to a power source such as a 5V power supply and must be electrically connected to DC 10V pin. XTAL1 pin 13 and XTAL2 pin 12 can be used with respect to an internal inverting oscillator amplifier, for example, for connection to an external oscilloscope for testing if necessary, or to act as an external clock signal, for example . AREF pin 32 can be used as the analog reference pin for ADC pins 33 to 40, and RESET pin 9 can allow the microcontroller to reset. Pins 1 - 7 (PB0-PB7), pins 22-29 (PC0-PC7) and pins 14-21 (PD0-PD7) can act as 8-bit bidirectional I / O ports (input / output), for example, to provide one or more output signals and / or to program the microcontroller 36.
[0109] Figure 7 is a schematic representation of the apparatus for programming the microcontroller 36 of the dirt detection apparatus 20 according to the disclosed examples. In the examples, the apparatus for programming the microcontroller 36 comprises a general-purpose computer 66, an interface board 68, and the microcontroller 36 (a portion of the pinout diagram of Figure 6 for the microcontroller 36 is illustrated in the example figure 7 to facilitate understanding of the drawing). In the examples, pins 6-11 of microcontroller 36 are operatively connected to interface board 68 via suitable cable and connectors. Power can be supplied from interface board 68 to microcontroller 36 through pin 10 VDC and pin 11 GND. In the examples, a program written in a suitable programming language can be uploaded from computer 66 to microcontroller 36 through interface board 68 so that the microcontroller can help provide the functionality of the apparatus as described in this document. In the examples, the programming language is C, although it will be appreciated that other suitable programming languages could be used and other apparatus for microcontroller programming could be used. In the examples, the dirt detection circuit comprises an interface port that can be connected to the interface board via a suitable connector mounted in the housing 32. Therefore, in the examples, the operating conditions of the detection apparatus Soiling can be modified or adapted as needed, for example if different time scales or measurement durations are required. In general, in the examples, the microcontroller is externally programmable to control the functionality of the soil detection apparatus. This can help provide a more flexible measurement system for soil detection.
[0111] In the examples, power is provided to the microcontroller 36 from the voltage regulator 40. Figure 8 is a schematic diagram of a voltage regulation circuit for providing electrical power to the microcontroller in accordance with the disclosed examples. In particular, in the examples the voltage regulator 40 comprises a voltage regulator circuit as illustrated in Figure 8.
[0113] In the examples, the voltage regulator circuit comprises a voltage regulator integrated circuit 70, a battery 72, a first capacitor 74 and a second capacitor 76. In the examples, the voltage regulator integrated circuit 70 is a regulator integrated circuit positive voltage (IC) model number LM7805 manufactured by STMicroelectronics (RTM), with a pin arrangement as schematically illustrated in the example in Figure 9. In the examples, the battery is a 9-volt battery, for example, a PP3 battery, the first capacitor 74 is a 10pF electrolytic capacitor, and the second capacitor is a 0.10pF electrolytic capacitor connected as shown in Figure 8. However, it will be appreciated that other IC voltage regulators can be used, suitable capacitors and batteries. In other examples, the battery may be battery 46 with suitable voltage regulation, as appropriate. In the examples, the voltage regulator circuit is operatively connected to the microcontroller 36 through pin 10 VDC and pin 11 GND of microcontroller 36 to be able to provide a 5V supply.
[0114] Fig. 10 is a schematic diagram of the connection arrangement of a pyranometer and a shunt resistor used in the dirt detection apparatus according to the disclosed examples. In particular, the example of FIG. 10 shows the shunt resistor 38, the pyranometer 24, and a portion of the microcontroller pin arrangement (to facilitate understanding of the drawing). In the examples, in order to measure an output voltage of the pyranometer 24, the pyranometer 24 is operatively connected to a first analog-to-digital converter (ADC) of the microcontroller 36 through pin 31 GND and pin 40 RA0 (ADC0) . More generally, in the examples, the output voltage of the pyranometer 24 can be considered as an irradiation signal that refers to a level of irradiation of light incident on the pyranometer 24.
[0116] In the examples, the shunt resistor 38 is operatively connected to the microcontroller 36 in order to be in electrical communication with the microcontroller 36. In the examples, the shunt resistor is operatively connected to a second analog-to-digital converter (ADC ) of the microcontroller 36 through pin 31 GND and pin 39 PA1 (ADC1) to be able to measure the voltage across the shunt resistor 38. In the examples, shunt resistor 38 comprises a CADDOCK model SR10 shunt resistor Electronics, with a nominal power of 1 W and a resistance of 0.008 W, and with a maximum operating current of 11 A. It also works with practically no reduction of the nominal load up to a temperature of 70 degrees Celsius, which can make it more suitable for use in arid and desert areas. In the examples, the maximum short-circuit current of the photovoltaic panel 22 (for example, the FS-41 15-3 model) is 1.83 A. Therefore, for example, the electrical output of the photovoltaic panel 22, such as the Short circuit current of the photovoltaic panel 22, can be measured using shunt resistance 38 and calculated by Ohm's law from the voltage input to the second analog-to-digital converter ADC of the microcontroller 36. However, it will be appreciated that other shunt resistors and photovoltaic panels and measure the electrical output of photovoltaic panel 22 in other suitable ways, such as using an ammeter or voltmeter.
[0118] More generally in the examples, the dirt detection apparatus comprises shunt resistor 38 arranged to be connectable between the output terminals of the photovoltaic panel 22, wherein the measuring means (such as the microcontroller 36) is operable to measure the short-circuit current per connection through shunt resistor 38. In other words, in the examples, the predetermined operating condition is a short-circuit current of the photovoltaic panel 22. In others For examples, the predetermined operating condition is a position on the current voltage curve of the photovoltaic panel 22 where the photovoltaic panel 22 is operable to produce maximum power. However, this may vary with the operating temperature of the photovoltaic panel 22 and may require a more complex circuit to establish the predetermined operating condition. In the examples, the short circuit current of the photovoltaic panel 22 is substantially proportional to the solar irradiation, and the variations in the temperature of the solar cell are generally negligible. For example, in the case of photovoltaic panel 22 (FS-41 15-3), as used in the disclosed examples, the short-circuit current can vary by 0.04% / ° C compared to the short-circuit current under standard test conditions at 25 ° C. In comparison, a maximum power output of the PV FS41 13-3 panel in the examples may change by 0.28% / ° C compared to standard test conditions at 25 ° C. In general, other photovoltaic panels and modules have a similar temperature trend dependent on the short-circuit current and the maximum power. Thus, for example, measuring the short-circuit current can provide a more accurate indication of the level of dirt, as well as help to simplify the circuitry required to detect the level of dirt.
[0120] In the examples, the measured short circuit current of the photovoltaic panel 22 that is related to a level of contamination of the panel 22 is compared to an expected short circuit current of the photovoltaic panel 22 calculated from the output of the pyranometer 24 based on the signal of irradiation. More generally, as mentioned above, in the examples, the fouling detection apparatus is operable to compare the measured electrical output of the photovoltaic panel in the predetermined operating condition, such as the short-circuit current of the photovoltaic panel 22, with the reference output value, eg, of the pyranometer 24, in order to generate a comparison value. In the examples, the comparison value can be used to determine whether a cleaning signal or other signal related to a soil level can be output, as will be described in more detail below.
[0122] Fig. 11 is a schematic diagram of a microcontroller output signal path used in the dirt detection apparatus according to disclosed examples. In the example shown in Figure 11, the PBO (XCK / TO) pin 1 and the GND pin 11 of the microcontroller are operable to output a first logic signal, for example, depending on a logic level of the microcontroller 36 based on the comparison value. In the examples, the first logic signal is 0V or 5V although it will be appreciated that other suitable logic signals can be used. In the examples, pins 1 and 11 of microcontroller 36 may be operatively connected to second relay 50a to allow the first output signal 50a to be generated. In the examples, the first output signal 50a is operable to be output when the comparison value is greater than the cleaning threshold value.
[0124] In the examples, pin 2 PB1 (T1) and pin 11 GND of the microcontroller are operable to output a second logic signal, for example, dependent on a logic level of the microcontroller 36 based on the comparison value. In the examples, the second logic signal is 0V or 5V although it will be appreciated that other suitable logic signals can be used. In the examples, pins 2 and 11 of microcontroller 36 can be operably connected to third relay 52 to allow second output signal 52a to be generated. In the examples, the second output signal 52a is a warning signal indicating that, for example, a cleanup event may be needed soon. In the examples, the warning signal is operable to be emitted when the comparison value is between a warning threshold value and the cleaning threshold value. In the examples, the warning threshold value is lower than the cleaning threshold value. In other examples, the warning signal can be omitted and the third relay 52 is not used.
[0126] In the examples, pin 3 PB2 (AIN0 / INT2) and pin 11 GND of the microcontroller are operable to output a third logic signal, for example, dependent on a logic level of the microcontroller 36 based on the comparison value. In the examples, the third logic signal is 0V or 5V although it will be appreciated that other suitable logic signals can be used. In the examples, pins 3 and 11 of microcontroller 36 can be operatively connected to fourth relay 54 to allow third output signal 54a to be generated. In the examples, the third output signal 54a is operable to be output when the comparison value is less than or equal to the cleaning threshold value. In the examples, the third output signal 54a is an inactive signal, for example, to indicate that the photovoltaic panel does not need cleaning. In the examples where a warning signal is applied, the third output signal 54a is output when the comparison value is lower than the cleaning threshold value and also lower than the warning threshold value. Thus, for example, the latent signal can allow a PV plant operator to determine that a cleaning event does not need to be scheduled and can therefore help improve the efficiency of cleaning event scheduling.
[0127] Although pins 1, 2, 3, and 11 have been described with reference to the first, second, and third output signals 50a, 52a, and 54a respectively, it will be appreciated that other suitable pins of the microcontroller could be used. It will also be appreciated that the inactivity signal, the cleaning signal, and the warning signal may be generated in other suitable ways. Furthermore, in the examples, one or more of the first output signal 50a, the second output signal 52a, and the third output signal 54a can be used to form a current path between the battery and a signal element such as a lamp or an audio output element such as a speaker or piezoelectric buzzer through current path 57 with battery 46.
[0129] Figure 12 is a schematic connection diagram of the voltage regulating circuit to the light sensor 44 used in the dirt detection apparatus 20 according to disclosed examples. As already mentioned, in the examples the dirt detection apparatus comprises a light sensor 44. In the examples, the light sensor 44 is operable to detect an illumination level of the light incident on the light sensor 44 In examples, the apparatus 20 is operable to perform fouling level detection when the illumination level is greater than a threshold illumination level. In the examples, the light sensor 44 comprises the light sensor switch, model AS-20 manufactured by Atoplee. In the examples, the threshold illumination level can be such that fouling detection is performed during the day, for example.
[0131] In the examples, the dirt detection circuitry comprises switch 56. In the examples, switch 56 is operatively connected between voltage regulator 40 and light sensor 44, although it will be appreciated that other wiring configurations are possible. . In the examples, switch 56 is operable to provide a manual override so that a soil detection cycle can be performed at the instigation of a user. In the example, switch 56 comprises a switch such as a ST series switch manufactured by Carling Technologies. However, it will be appreciated that any suitable type of switch can be used. In the examples, switch 56 allows manual activation or deactivation of the dirt detection measurement. In the examples, as illustrated in Figure 12, the voltage regulator 40 may be in electrical connection with the microcontroller 36 (for example, to pin 10 VDC and pin 30 AVCC) through light sensor 44 and switch 56 to be able to provide power to the microcontroller 36. However, other suitable connection arrangements could be used to be able to provide power to the microcontroller 36.
[0132] As already mentioned, in the examples, the battery 46 is arranged to be able to supply power to the apparatus. In the examples, the photovoltaic panel 22 may be in electrical connection with the battery 46 to be able to charge the battery 46. In the examples, the photovoltaic panel 22 is in electrical connection with the battery 46 through the charge controller 42 to be able to charge. battery 46. In the examples, the charge controller 42 is operable to control a charge setting of the battery 46, for example, by controlling a charge rate from the photovoltaic panel 22 to the battery 46. In the examples, the charge controller The load is a 12V-3A model Star03 manufactured by Lumiax, although it will be appreciated that other types of charge controller can be used. In the examples, the soil detection circuit is operable to perform soil detection in dependence on a soil detection control signal, for example, generated by the microcontroller. In the examples, power can be supplied to the microcontroller 36 from the battery 46, for example, using a suitable voltage regulation circuit. However, in other examples, the microcontroller can be powered by any other suitable power source, such as a 9V battery or a regulated electrical network. However, the use of one or more batteries can allow the apparatus 20 to operate in remote locations without an external support infrastructure.
[0134] In the examples, the photovoltaic panel 22 is operable to charge the battery 46 when dirt detection is not performed. In the examples, a soil detection cycle is performed at substantially regular intervals, as described in more detail below. In other words, more generally in the examples, the apparatus 20 is operable to measure the electrical output of the photovoltaic panel at predetermined time intervals to detect a soil level of the photovoltaic panel 22. In the examples, the apparatus 20 is operable to measure the electrical production of the photovoltaic panel 22 for a predetermined duration.
[0136] As already mentioned, in the examples, the fouling detection circuit comprises a first relay 48 which is operatively connected to the pyranometer 24, the microcontroller 36, the photovoltaic panel 22 and the charge controller 42. In the examples, the first Relay 48 is a double pole bipolar relay (DPDT) as a 5V, 8 pin relay, model number JW2SN-DC5V manufactured by Panasonic. However, it will be appreciated that other types of relays can be used. In the examples, the first relay 48 comprises a coil comprised of a pair of coil terminals, a first set of relay contacts, and a second set of relay contacts. In the examples, the first set of relay contacts comprises a first common terminal, a first terminal normally open and a first normally closed terminal, in which current can flow between the first common terminal and the first open terminal or the first normally closed terminal, depending on whether the coil is energized (current flows through the coil). In the examples, the second set of relay contacts comprises a second common terminal, a second normally open terminal, and a second normally closed terminal, in which current can flow between the second common terminal and the second open terminal or the second terminal. normally closed, depending on whether the coil is on (current flowing through the coil). In other words, for example, the first relay 48 can function as a double pole relay of the bipolar type.
[0138] In the examples, the microcontroller 36 is operatively connected to the coil so that the coil can be activated and thus the first relay 48 can be switched. In the examples, the dirt detection control signal comprises a relay control signal. In the examples, the coil terminals are operatively connected to pin 11 GND and pin 4 PB3 (AIN1 / OCO) so that the coil can be energized by the relay control signal, as an output signal from 5V of the microcontroller 36, for example, to enable the dirt detection apparatus to perform the dirt detection or control the dirt detection measurement.
[0140] In the examples, the first common terminal is electrically connected to an electrical terminal of the photovoltaic panel 22, and the shunt resistor 38 is electrically connected to the first normally open terminal, so that current can flow through the shunt resistor 38. when the coil is energized, for example, in response to the relay control signal from the microcontroller. In the examples, the pyranometer 24 is operatively connected to pins 40 and 31 of the microcontroller 36, as indicated in the example of Figure 10, through the second common terminal and the second normally open terminal, so that the Pyranometer 24 may be in electrical connection with microcontroller 36 when the coil of first relay 48 is energized, for example, in response to the control signal from microcontroller relay 36. In the examples, the first normally closed terminal is connected in a operational to the charge controller 42, so that the battery 46 can be charged when the coil is not energized, for example, when dirt detection is not performed. In the examples, the second normally closed terminal is not connected. In other words, in the examples, the dirt detection circuit is operable to perform dirt detection based on the relay control signal.
[0141] In other examples, the pyranometer 24 and shunt resistor 38 could be operatively connected to the normally closed terminal of the relay 48, and the charge controller 42 connected to a normally open terminal so that the battery 46 can be charged when the coil is energized. However, it will be appreciated that other connection arrangements may be used.
[0143] In other examples, the connection to the charge controller 42 may be omitted and other arrangements used to charge the battery 46. Furthermore, it will be appreciated that the battery 46 could be omitted with appropriate modifications to the output signals of the microcontroller 36, such as output signals 50a, 52a and 54a.
[0145] Next, examples of methods of operation of the soil detection apparatus will be described with reference to Figures 13, 14A and 14B. Fig. 13 is a flow chart of a method for detecting the dirt level of a photovoltaic panel using a dirt detecting apparatus according to the examples of the disclosure. In the examples, a dirt detection method is performed to detect the dirt level of a photovoltaic panel using the floor detection apparatus 20. As already mentioned, in the examples, the dirt detection comprises the photovoltaic panel 22 and pyranometer 24 which is positioned relative to photovoltaic panel 22 so that photovoltaic panel 22 and pyranometer 24 can receive substantially the same level of solar radiation as the other.
[0147] In a step s100, the photovoltaic panel 22 generates an electrical output in response to the light incident on the panel and as a function of the level of dirt on the photovoltaic panel 22. In the examples, the electrical production is a photovoltaic current that can be measured , for example, by shunt resistor 38. However, in other examples, the electrical output could be the power generated by the photovoltaic panel, for example, determined from a measured output voltage and the measured output current using the equation power = voltage x current. However, it will be appreciated that other techniques may be used to measure the current, voltage, power of other forms of electrical output from the photovoltaic panel 22.
[0149] In a step s102, the pyranometer 24 generates an irradiation signal that is related to a level of irradiation of light incident on the pyranometer 24. For example, the signal of Irradiation may be related to a level of solar radiation incident on the pyranometer 24.
[0151] In a step s104, a reference output value is calculated from the irradiation signal, for example, by the microcontroller 36, although other techniques could be used. In the examples, the reference output value refers to an ideal electrical output of the photovoltaic panel 22 in a predetermined operating condition. In the examples, the predetermined operating condition is a short circuit current of the photovoltaic panel 22. In the examples, the ideal electrical output is a short circuit current of the photovoltaic panel 22 that would be expected to obtain for the photovoltaic panel 22 when it is in a substantially clean state (eg, substantially free of dirt). However, it will be appreciated that other predetermined operating conditions could be used, such as a bias position of the photovoltaic panel 22 in which the maximum power can be obtained from the photovoltaic panel. As mentioned above, using short circuit current as the predetermined operating condition can help reduce circuit complexity and reduce the temperature dependence of the reference output value.
[0153] In a step s106, the electrical output of the photovoltaic panel 22 in the predetermined operating condition is measured, for example, by an ADC of the microcontroller 36 measuring the voltage across the shunt resistor 38. However, it will be appreciated that they could be used other techniques to measure the electrical output of the photovoltaic panel in the predetermined operating condition, for example, if the maximum power is to be measured.
[0155] In a step s108, the measured electrical production of the photovoltaic panel 22 in the predetermined operating condition is compared with the reference output value in order to generate a comparison value. In the examples, the microcontroller 36 is operable to compare the measured electrical output with the reference output value to generate the comparison value. However, it will be appreciated that other suitable arrangements may be used, such as a comparison circuit.
[0157] In a step s110, it is determined whether the comparison value is greater than a cleaning threshold value. In the examples, the microcontroller 36 is operable to determine whether the comparison value is greater than the cleaning threshold value, although it will be appreciated that Other techniques and circuits or apparatus could be used. In the examples, the cleaning threshold value can be established by programming the microcontroller appropriately, for example, using the apparatus described above with reference to Figure 7.
[0159] If the comparison value is larger than the cleaning threshold value, then the cleaning output signal is output in a step s112, for example, the corresponding output signal 50a. In other words, for example, the cleaning signal is output when the comparison value is greater than a cleaning threshold value. For example, the cleaning signal may indicate that the panel needs to be cleaned. However, if the comparison value is less than the cleaning comparison value, or less than or equal to the comparison, then, in a step s114, a latent signal is output, corresponding for example to the output signal 54a. As mentioned above, in some examples, a warning signal may also be output when appropriate, as described in more detail below with reference to Figures 14A and 14B.
[0161] Figures 14A and 14B are a flow chart of a method for detecting a soil level of the photovoltaic panel 22 by measuring the voltage across the shunt resistor 38 according to disclosed examples. The flow charts of Figures 14A and 14B should be considered together as part of the same process flow chart for measuring a soil level of the photovoltaic panel 22 of the disclosed examples. However, two drawing sheets have been used to illustrate the flow chart for ease of understanding, clarity and space. In Figures 14A and 14B, the circled letters A, B, and C indicate where the flowchart meets between pages with similar letters that are joined as a flow. For example, circle A of Figure 14B joins circle A of Figure 14A. In the example of Figures 14A and 14B the method is performed under the control of the microprocessor 36, although it will be appreciated that other ways of applying the method may be used.
[0163] In a step s200, it is determined whether an auto light switch sensor is on. In the examples, the auto light switch sensor comprises the light sensor 44. For example, if the light level incident on the light sensor 44 is greater than the illumination threshold, it is determined that the auto switch sensor light is on. For example, the threshold illumination level may correspond to a minimum illumination level typically found during the day at the location where the apparatus 20 is located. In other words, for example, the Dirt detection can be arranged to take place during the day and not at night.
[0165] If, for example, the auto light switch sensor is determined to be off, for example, because the light incident on the light sensor 44 is less than the threshold illumination level, then a waiting period is initiated at a step s202. After the waiting period is over, the procedure goes to step s200. In the examples, whether the method step s202 goes to step s200 depends on the state of switch 56. For example, step s202 can go to step s200 if switch 56 is closed. However, if switch 56 is open, for example, then processing stops and method step S202 does not go to step s200, for example, due to manual override of the dirt detection measurement by an operator. who uses the switch. In other examples, switch 56 may be used to override the auto light switch sensor so that steps s200 and s202 are not performed. This can occur if an operator wishes to manually override when a dirt detection measurement occurs so that it can be performed when bypassing the light sensor 44, for example.
[0167] In the examples, the timeout period can correspond to a predetermined time period, such as 10 minutes, 20 minutes, 30 minutes, and the like, although any time period can be used. In other examples, the waiting period is less than 10 seconds, so that a dirt detection measurement can be timely performed when the illumination threshold level is exceeded, for example.
[0169] If, for example, it is determined that the automatic light switching sensor is turned on in step s200, then in step s204, a first parameter T1 is set. In the examples T1 is an integer in the range 1 <T1 <30, where T1 is measured in minutes (for example, T1 = 1 ® 30 min.). T1 is initially set to T1 = 1 but can subsequently be increased iteratively by making T1 = T1 ', where the value of T1' is then defined in an incremental step (step s238) as described below.
[0171] In a step s206, a second temporal parameter T2 is set. In the examples, T2 is an integer in the range 10 <T2 <60, where T2 is measured in seconds (for example, T2 = 10 ® 60 sec.). T2 is initially set at T2 = 10 but can be increased subsequently iteratively making T2 = T2 ', where the value of T2' is then defined in an incremental step (step s232) as described below.
[0173] In a step s208, a third time parameter T3 is set. In the examples, T3 is an integer in the range 1 <T2 <10 where T3 is measured in seconds (for example, T3 = 1 ® 10 sec.). T3 is initially set to T3 = 1 but can subsequently be incremented iteratively by making T3 = T3 ', where the value of T3' is then defined in an incremental step (step s226) as described below.
[0175] One or more of the steps s204, s206 and s208 can be performed in the order in which they are described, or two or more of these steps can be performed in parallel. Furthermore, it will be appreciated that one or more of T1, T1 ', T2, T2', T3, and T3 'could be any other number (eg, an integer, real, complex, rational, or irrational), and that they could be used other ranges for their values. It will also be appreciated that initialization values other than those mentioned above could be set.
[0177] In a step s210, an analog voltage from shunt resistor 38 is measured to generate a first analog signal, for example, by inputting a first analog-to-digital converter (ADC) of microcontroller 36. In other words, for example, An analog voltage across shunt resistor 38 can be measured to determine a current through shunt resistor 38.
[0179] In a step s212, the first analog signal is converted to a first digital signal by the first ADC of the microcontroller 36.
[0181] In a step s214, the microcontroller 36 can multiply the first digital signal by a shunt resistance factor to calculate a short-circuit current value (a) of the photovoltaic panel 22, for example, which refers to a dirt level of the panel photovoltaic. For example, the value of the short-circuit current can be calculated from the voltage measured across the shunt resistor 38 using Ohm's law. In the examples, the resistance of resistor 38 is 0.008 ohms, although other suitable values could be used.
[0183] In a step s216, an analog voltage from pyranometer 24 is measured to generate a second analog signal, for example, by inputting a second converter analog-to-digital (ADC) of microcontroller 36. In other words, for example, an analog voltage generated by pyranometer 24 can be measured to determine an irradiation level of pyranometer 24.
[0185] In a step s218, the second analog signal is converted to a second digital signal by the second ADC of the microcontroller 36.
[0187] In a step s220, the microcontroller 36 can multiply the second digital signal by a pyranometer factor to calculate a solar irradiance value of the light incident on the pyranometer 24. In other examples, the microcontroller 36 can determine the solar irradiation value at through a look-up table (LUT) stored in the microcontroller 36 or in the external memory that, for example, relates the irradiation value with the output voltage of the pyranometer. However, it will be appreciated that other suitable techniques may be used to determine the level of irradiation from the output of pyranometer 24.
[0189] In a step s222, an expected short-circuit current (b) associated with the photovoltaic panel 22 in a clean state is calculated by the microcontroller 36 from the irradiance value obtained from the pyranometer 24. In the examples, the short-circuit current of the photovoltaic panel 22 It is substantially proportional to the irradiation of the light that strikes the photovoltaic panel. Therefore, the irradiation value obtained from the pyranometer 24 can allow an indication of what the measured short-circuit current would be for the photovoltaic panel 22 in a clean state. However, other techniques can be used to obtain the expected short-circuit current b) for a clean panel, such as by means of a lookup table or other known relationship.
[0191] In the examples, steps S210, s212, and s214 are performed in parallel with steps s216, s218, s220, and s222. However, it will be appreciated that other orders of performance may be used between steps, such as a combination of sequential and parallel or sequential performance.
[0193] In a step s224, the microcontroller determined whether the value of T3 = 10 seconds. If not, then in a step s226, the value of T3 is increased by 1 to generate an increased value T3 '= T3 1. In the examples, the value of the short-circuit current (a) and the expected short-circuit current (b) measured in step s210 to s222 are stored in the memory of the microcontroller 36 in step s224 to generate a plurality of values stored current. Processing then proceeds from step s226 to step s208. In other words, more generally, in the examples, the measurement of the short-circuit current (a) of the photovoltaic panel 22 and the expected short-circuit current (b), as obtained from the pyranometer 24, occurs at a first default frequency. In the example of Figures 14A and 14B, the first predetermined frequency is such that the measurement of the short circuit current (a) of the photovoltaic panel 22 and the expected short circuit current (b) occurs every 1 second, although it will be appreciated that other time periods could be used.
[0195] If T3 = 10 seconds, then processing proceeds to step s228. In step s228, the microcontroller 36 calculates an average of the measured short-circuit current values (a) and the expected short-circuit current values (b) from the plurality of current values stored in memory in step s224. to generate an average value of measured short circuit current {a} and an average value of expected short circuit current {b}. In other words, more generally, in the examples, the calculation of the measured short-circuit current average values and the expected short-circuit current average values occurs at a second predetermined frequency. In the example of Figures 14A and 14B, the second predetermined frequency is such that the calculation of the mean values {a} and {b} occurs every 10 seconds, although it will be appreciated that other time periods could be used.
[0197] In a step s230, the microcontroller determines whether the value of T2 = 60 seconds. If not, then in a step s232, the value of T2 is increased by 10 to generate an increased value T2 '= T2 10. In the examples, the mean value of the short-circuit current {a} and the expected mean value of the short circuit current {b} calculated in step s228 are stored in the memory of the microcontroller 36 in step s230 to generate a plurality of stored average values. Processing then proceeds from step s232 to step s206.
[0199] If T2 = 60 seconds, then processing proceeds to step s234. At step s234 the microcontroller 36 calculates the respective amp-hour (AH) values from the plurality of stored average values for {a} and {b} based on the elapsed time and the stored average values. The microcontroller then adds the respective amp-hour values to generate the summed amp-hour (AH) values [a] and [b]. In other words, more generally, in the examples, the calculation and sum of the summed amp-hour values occurs at a third predetermined frequency. In the example of Figures 14A and 14B, the third predetermined frequency is such that the calculation and summation of the summed amp-hour values [a] and [b] occurs every 60 seconds (every minute), although it will be appreciated that other time periods could be used.
[0201] In a step s236, the microcontroller determines whether the value of T1 = 60 minutes. If not, then in a step s238, the value of T1 is increased by 1 to generate an increased value TT = T 1. In the examples, the summed amp-hour values [a] and [b] calculated in step s234 are stored in the memory of the microcontroller 36 in step s236 to generate a plurality of stored amp-hour values. Processing then proceeds from step s238 to step s204. The use of ampere-hour calculations and / or averaging can help reduce the likelihood of a false signal being emitted, for example due to the instantaneous measurement of short-circuit current exceeding a threshold.
[0203] If T1 = 30 minutes, then processing proceeds to step s240. In step s240 the microcontroller 36 sums the ampere hour values stored in memory in step s236 to generate the summed total ampere hours (AH) [a '] and [b']. In other words, more generally, in the examples, the summation of the stored amp-hour values occurs after a predetermined period of soil measurement time. In the example of Figures 14A and 14B the predetermined soil measurement time period is 30 minutes, although it will be appreciated that other time periods could be used. In other words, in the examples, a complete soil detection cycle takes substantially 30 minutes to complete.
[0205] In a step s242, the ratio [b '] / [a'] is calculated by the microcontroller 36. In the examples, the ratio [b '] / [a'] can be considered as a comparison value as mentioned above with reference to Figure 13 and to the description above.
[0207] In a step s244, the microcontroller 36 determines whether the ratio [b '] / [a'] is between a first threshold and a second threshold. In words, for example, the microcontroller determines whether the first threshold <[b '] / [a'] <second threshold. In the examples, the first threshold corresponds to the alert threshold mentioned above, and the second threshold corresponds to the cleaning threshold mentioned above.
[0208] If the ratio [b '] / [a'] is between the first threshold (warning threshold) and the second threshold (cleaning threshold), then in a step s246, the warning signal is emitted and the others stop exit signs. However, in other examples, the step of stopping other output signals in step s246 may be omitted.
[0210] If the ratio [b '] / [a'] is not between the first and the second threshold, then in a step s248, the microcontroller determines if the ratio [b '] / [a'] is greater than the second threshold ( cleaning threshold).
[0212] If the ratio [b '] / [a'] is greater than the second threshold (cleaning threshold), then in a step s250 the cleaning signal is output and other signals are stopped. However, in other examples, the step of stopping other output signals at s250 can be skipped.
[0214] If the ratio [b '] / [a'] is not greater than the second threshold (cleaning threshold), then in a step s252 the inactive signal is output.
[0216] In a step s254, the signal that was issued in step s246, s250 or s252 is kept active (continues to be broadcast). In other words, for example, processing may proceed from step s246 to step s254, from step s250 to step s254, and from step s252 to step s254. This can allow a plant operator to easily view the dirt status of the PV panel, even if the dirt detection cycle is not currently running. In the examples, the soil detection procedure (soil detection cycle) can be performed in a predetermined soil cycle measurement range. Using the default fouling cycle measurement interval can help save energy because soil detection is not continuous. In addition, the memory requirements of the microprocessor can be reduced, which can help reduce costs. In the examples, the fouling cycle measurement interval is 2 hours, although it will be appreciated that other time intervals could be used. After the fouling cycle measurement interval has elapsed, processing proceeds to step s200.
[0218] It will be appreciated that while the steps of Figures 13, 14A, and 14B have been described in a substantially sequential manner, they do not need to be performed in that order and may be performed in another order. It will also be appreciated that one or more of the steps could be performed sequentially and / or parallel to each other, or some steps may be omitted, such as steps s234, s236, s238 and s204. It will be appreciated that the time periods relevant to the method described in Figures 14A and 14B, such as the predetermined first, second and third frequencies, the predetermined soil measurement time period, and the fouling cycle measurement interval may be varied or set. , for example, by programming the microcontroller 36. For example, the fouling cycle measurement interval may vary by season. Furthermore, if, for example, the weather is forecast to be cloudy, it may be preferable to measure the soil level over a shorter period, for example, as determined by the fouling cycle measurement time period, in order to Try to ensure a more consistent measurement during the measurement period.
[0220] Furthermore, it will be appreciated that the first threshold (alert threshold) and the second threshold (cleaning threshold) may vary depending on the performance requirements.
[0222] In the examples, the apparatus 20 comprises a communication module operable to allow the microcontroller 36 to communicate with an external network or an apparatus such as the control network of a photovoltaic plant through a suitable communication interface such as wifi, ethernet, wireless cellular network and the like. In the examples, the microcontroller is operable to be programmable, for example, through the communication module, to set one or more of the first threshold, the second threshold, the timing of the dirt detection measurements, and the increment steps. and the ranges of T1, T2 and T3. This may, for example, allow apparatus 20 to be remotely programmed according to the operating conditions at its location. Furthermore, in the examples, the apparatus 20 is operable to emit one or more of the output signals, such as the inactivity signal, the warning signal, and the cleaning signal through the communication module to a remote location such as the room. control of a photovoltaic plant. Thus, apparatus 20 can, for example, be remotely operated if desired.
[0224] In the examples, the apparatus is operable to generate a ranking signal based on the comparison value. In the examples, the rating signal relates to an expected production of one or more other photovoltaic panels having substantially the same level of dirt as the photovoltaic panel of the apparatus. In the examples, the microcontroller 36 is operable to produce the qualification signal, for example, through the communication module. For example, if the dirt detection apparatus 20 is positioned so that it can receive substantially the same level of dirt as one or more photovoltaic panels of a photovoltaic plane, the classification signal can be used by a photovoltaic plant operator to determine the expected electrical production of the photovoltaic plant.
[0226] For example, the ratio [b '] / [a'] calculated as mentioned above in step s242 can be used to indicate or predict an expected electrical output of a second photovoltaic panel (or a plurality of other photovoltaic panels) that has substantially the same level of dirt as the photovoltaic panel 22, so that the expected performance level of the second panel or of the plurality of panels is proportional to the ratio [b '] / [a'] compared to the expected performance of the second photovoltaic panel (or of the plurality of panels) when there is practically no dirt. In other words, in the examples, the apparatus 20 is operable to evaluate the impact of fouling on the production of the photovoltaic panels based on the comparison value and the measured short-circuit current. This can help the operator of a photovoltaic plant to predict the power production of the plant more accurately and thus can aid in power grid management, power distribution, and profit prediction.
[0228] It will be appreciated that when a photovoltaic panel or panels is mentioned, one or more photovoltaic modules may be used in place of or in combination with one or more photovoltaic panels. It will also be appreciated that a photovoltaic panel or panels may comprise one or more photovoltaic modules, as appropriate. It will also be appreciated that the exemplary photovoltaic panel (s) of the disclosure could have any appropriate physical configuration, such as having a substantially flat light-receiving surface, or a curved light-receiving surface, for example.
[0230] The apparatus and method of the examples of the disclosure can allow easy integration with existing photovoltaic plants, as well as being able to be used as a stand-alone unit, for example, to determine if a site is suitable for a photovoltaic plant. In addition, different types of photovoltaic panels can be used as a reference photovoltaic panel (such as photovoltaic panel 22), with microcontroller 36 programmed as appropriate. In other words, for example, the apparatus and method of the disclosure can help provide a more flexible and easily adaptable way of determining the soil level of a photovoltaic panel.
[0231] Although various examples have been described herein, these are provided by way of example only and many variations and modifications of such examples will be apparent to the skilled person and will be within the spirit and scope of the present invention, which is defined in the appended claims and their equivalents.

权利要求:
Claims (14)
[1]
1 Dirt detection apparatus, operable to detect a level of dirt from a photovoltaic panel, the apparatus comprising:
a photovoltaic panel operable to generate an electrical output in response to light incident on the panel and as a function of the level of dirt on the photovoltaic panel;
a pyranometer operable to generate an irradiation signal that is related to an irradiation level of the light incident on the pyranometer, the pyranometer being positioned with respect to the photovoltaic panel so that the photovoltaic panel and the pyranometer can receive substantially the same level solar radiation than the other;
a calculation means operable to calculate a reference output value of the irradiation signal that is related to an ideal electrical output of the photovoltaic panel in a predetermined operating condition;
a measuring means operable to measure the electrical output of the photovoltaic panel in the predetermined operating condition;
a comparison means operable to compare the measured electrical output of the photovoltaic panel in the predetermined operating condition with the reference output value in order to generate a comparison value; Y
an output means operable to output a cleaning signal when the comparison value is greater than a cleaning threshold value.
[2]
2. Dirt detection apparatus according to claim 1, wherein the output means are operable to produce a latent signal when the comparison value is less than or equal to the cleaning threshold value.
[3]
3. Dirt detection apparatus according to claim 1 or claim 2, wherein the output means are operable to emit a warning signal when the comparison value is between a warning threshold value and the threshold value. cleaning.
[4]
4. Dirt detection apparatus according to any one of the preceding claims, wherein the predetermined operating condition is a short-circuit current of the photovoltaic panel.
[5]
5. Dirt detection apparatus, according to claim 4, comprising a shunt resistor arranged to be connected between the output terminals of the photovoltaic panel, in which the measurement means are operable to measure the short-circuit current per connection across the shunt resistor.
[6]
6. Dirt detection apparatus, according to any one of the preceding claims, comprising a battery arranged to be able to provide power to the apparatus, wherein the photovoltaic panel can be in electrical connection with the battery to be able to charge the battery.
[7]
7. - Dirt detection apparatus according to any one of the preceding claims, comprising a light sensor operable to detect an illumination level of the incident light on the light sensor, in which the apparatus is operable to perform the detection of the level of dirt when the level of illumination is greater than a threshold level of illumination.
[8]
8. - Dirt detection device according to claim 7 when it depends on claim 6, in which the photovoltaic panel is operable to charge the battery when dirt detection is not performed.
[9]
9. - Dirt detection apparatus according to any one of the preceding claims, wherein the apparatus is operable to measure the electrical output of the photovoltaic panel at predetermined time intervals to detect a level of dirt from the photovoltaic panel.
[10]
10. Dirt detection apparatus according to any one of the preceding claims, wherein the apparatus is operable to measure the electrical output of the photovoltaic panel for a predetermined duration.
[11]
11. - Dirt detection apparatus according to any one of the preceding claims, in which the photovoltaic panel comprises a plurality of thin-film photovoltaic cells.
[12]
12.
[13]
13. - Photovoltaic plant, comprising a plurality of photovoltaic panels for the generation of electricity, the photovoltaic plant comprising a dirt detection device according to any one of the preceding claims, wherein the dirt detection device is placed with respect to to one or more photovoltaic panels of the photovoltaic plant so that it receives substantially the same dirt as one or more photovoltaic panels of the photovoltaic plant.
[14]
14. - Dirt detection method to detect a level of dirt on a photovoltaic panel using a dirt detection device comprising a photovoltaic panel and a pyranometer positioned with respect to the photovoltaic panel so that the photovoltaic panel and the pyranometer can receive substantially the same level of solar radiation as the other, the method comprising:
generation, by the photovoltaic panel, of an electrical output in response to the light incident on the panel and as a function of the level of dirt on the photovoltaic panel;
generation, by the pyranometer, of an irradiation signal that is related to an irradiation level of the light incident on the pyranometer;
calculating a reference output value from the irradiation signal that is related to an ideal electrical output of the photovoltaic panel in a predetermined operating condition;
measuring the electrical output of the photovoltaic panel in a predetermined operating condition;
comparison of the measured electrical output of the photovoltaic panel in the predetermined operating condition with the reference output value to generate a comparison value; and issuing a cleaning signal when the comparison value is greater than a cleaning threshold value.

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同族专利:

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公开号 | 公开日

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JP2021517801A|2021-07-26|

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JOP20200200A1|2019-08-19|

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CN111869100A|2020-10-30|

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ES2787726R1|2020-10-20|

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WO2019158982A1|2019-08-22|

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AU2018408878A1|2020-07-23|

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US20200395892A1|2020-12-17|

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CA3087952A1|2019-08-22|

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法律状态:
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2021-11-25| PA2A| Conversion into utility model|Effective date: 20211119 |

优先权:

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申请号 | 申请日 | 专利标题

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AE60026318|2018-02-19|

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PCT/IB2018/052444|WO2019158982A1|2018-02-19|2018-04-09|Soiling detection apparatus and method|

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