ES1285699U - Dirt detection device. (Machine-translation by Google Translate, not legally binding) - Google Patents

Abstract

Dirt detection device, to detect a level of dirt on a photovoltaic panel, the device comprising: a photovoltaic panel adapted to generate an electrical output in response to light incident on the panel and as a function of the level of soiling of the photovoltaic panel; a pyranometer adapted 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 such that the photovoltaic panel and the pyranometer can receive substantially the same level of solar radiation than the other; calculation means adapted 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; measuring means adapted to measure the electrical output of the photovoltaic panel in the predetermined operating condition; comparison means adapted 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; and output means adapted to output a cleaning signal when the comparison value is greater than a cleaning threshold value. (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

Dirt detection device

field of invention

The present disclosure relates to a dirt detection apparatus.

State of the art

Solar photovoltaic (PV) installations in arid and desert areas are potentially affected by the frequent fouling caused by the precipitation of dust, sand and other suspended particles on the surface of the photovoltaic panels. The impact is further aggravated in humid weather, where the particles cumulatively stick to the surfaces of the photovoltaic panels forming a thick and substantially opaque layer of dirt. The situation turns out to be a serious problem that decreases the efficiency of the photovoltaic plant and, consequently, its profitability.

Therefore, PV plant operators can carry out regular PV panel cleaning events at a preset frequency, such as monthly or fortnightly. However, the actual need for cleanup events is likely to change, for example, based on changes in weather conditions. This can negatively affect the optimal performance of pre-scheduled cleaning events. For example, a cleaning event may occur or be scheduled when the panels do not need to be cleaned, or it may occur after the panel may actually need cleaning.

One way to address this issue is to detect the level of dirt on the photovoltaic panels. A cleaning event can then be arranged for when the panel needs to be cleaned, such as a dirt level reaching 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 such that it is exposed to dirty 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 PV module and the second PV module can then be compared to estimate the level of soiling.

However, 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 panel from dirt deposits which can be automatically or manually removed when a dirt measurement is to be performed. However, those arrangements can be expensive, mechanically complex, and prone to failure.

The examples of the present disclosure attempt to address or at least alleviate the aforementioned problems.

Summary of the invention

In a first aspect, there is provided a soil detection apparatus operable to detect the soil level of a photovoltaic panel, the apparatus comprising: a photovoltaic panel operable to generate 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 is related to an irradiation level of light incident on the pyranometer, the pyranometer being positioned with respect to the photovoltaic panel such that the photovoltaic panel and the pyranometer can receive substantially the same level of solar radiation than the other; calculating means operable to calculate a reference production value from the irradiation signal that is related 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 output of the photovoltaic panel in the predetermined operating condition with the reference output value to generate a comparison value; and producing means operable to produce a cleaning signal when the comparison value is greater than a cleaning threshold value.

In a second non-protected aspect, the description of a dirt detection method is provided to detect the 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: the generation, by the photovoltaic panel, of an electrical output in response to light incident on the panel and on function of the level of dirt on the photovoltaic panel; the 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 production value from the irradiation signal that is related to an ideal electrical output of the photovoltaic panel in a predetermined operating condition; the measurement of 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 outputting a cleaning signal when the comparison value is greater than a cleaning threshold value.

Other aspects and features are defined in the appended claims.

In the 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 measurement flexibility and reliability. In addition, 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 dirt detection to occur. For example, the need to clean the photovoltaic panel of the exemplary embodiments can be reduced because a predicted production that can correspond to what can be produced for a substantially clean photovoltaic panel can be predicted from the reference production value calculated from the irradiation as measured by the pyranometer.

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 clean signal is output. cleaning. For example, the cleaning signal may indicate that the photovoltaic panel, and thus other photovoltaic panels in a photovoltaic plant where the apparatus is located, may need cleaning. Therefore, for example, a cleaning event can be scheduled as appropriate depending on the level of dirt detected and therefore the efficiency of the 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 dirt measured at that location.

Description of the figures

Embodiments will now be described by way of example only with reference to the accompanying figures, in which like references refer to like parts, and in which:

Figure 1 is a schematic representation of an arrangement for measuring dirt by means of two photovoltaic panels.

Figure 2 is a schematic representation of a dirt detection apparatus according to embodiments.

Fig. 3 is a schematic circuit diagram of a dirt detecting apparatus according to exemplary embodiments.

Figure 4 is a schematic representation of the fouling of a crystalline silicon photovoltaic panel.

Figure 5 is a schematic representation of the fouling of a thin-film photovoltaic panel.

Fig. 6 is a schematic diagram of the pin layout of a microcontroller used in the dirt detection apparatus according to exemplary embodiments.

Figure 7 is a schematic representation of the apparatus for programming the microcontroller of the dirt detection apparatus according to embodiments.

Figure 8 is a schematic diagram of a voltage regulation circuit for providing electrical power to the microcontroller according to exemplary embodiments.

Fig. 9 is a schematic diagram of the arrangement of a voltage regulator used in the dirt detecting apparatus according to exemplary embodiments.

Fig. 10 is a schematic diagram of the connection arrangement of a pyranometer and a shunt resistor used in the dirt detecting apparatus according to exemplary embodiments.

Fig. 11 is a schematic diagram of an output signal path of the microcontroller used in the dirt detecting apparatus according to exemplary embodiments.

Fig. 12 is a schematic circuit diagram of the connection of the voltage regulation circuit to a light sensor used in the dirt detecting apparatus according to exemplary embodiments.

Detailed description of the invention

A dirt detection apparatus is disclosed. Various specific details are presented in the following description so that the exemplary embodiments may be better understood. However, it will be apparent to one skilled in the art that these specific details need not be used to develop the exemplary embodiments. On the contrary, the specific details known to those skilled in the art are omitted for clarity in the presentation of the examples.

Figure 1 is a schematic representation of an arrangement for measuring dirt by means of two photovoltaic panels. As mentioned above, a prior 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 such that it is exposed to dirty 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 its production. The output of the first photovoltaic module 10 and the second photovoltaic module 12 can then be compared to estimate the level of soiling. 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 which can be automatically or manually removed when a dirt measurement is to be performed. However, those arrangements can be expensive, mechanically complex, and prone to failure. Also, trying to keep a PV panel clean all the time in dry desert areas with a humid climate can be a difficult task.

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 electrical output in response to light incident on the panel 22 and in dependence on the level of soiling of the photovoltaic panel 22. In the examples, the photovoltaic panel 22 is a thin film photovoltaic panel. In examples, photovoltaic panel 22 is a thin film CdTe photovoltaic panel, model manufactured by First Solar. However, it is appreciated that other types of photovoltaic panel can be used such as a polycrystalline silicon panel.

In the examples, the apparatus also comprises a pyranometer 24 operable to generate an irradiance signal that is related to an irradiance level of light incident on the pyranometer 24. Pyranometers are typically used to measure solar irradiance. Typical pyranometers comprise a white metal casing, comprising a hemispherical glass dome under which a black metal absorber is placed so that it can be heated by solar radiation incident on the dome. The Typical thermopile pyranometers comprise a thermocouple and to generate a voltage the temperature difference between the absorber and the metal casing is measured. The voltage is generally proportional to the value of solar irradiation. In other words, for example, the pyranometer can work generally by measuring a difference in heat. Therefore, the pyranometer is less likely to require frequent cleaning, as may be the case when an irradiance detector comprising a photovoltaic reference cell is used.

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 may be used.

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 each other. For example, photovoltaic panel 22 and pyranometer 24 may have substantially the same angle and orientation as each other, and be positioned so that they do not occlude each other from solar radiation when soil detection apparatus 20 is deployed in a location. suitable.

In the examples, the apparatus 20 comprises a base and a support post 28 mounted on the base in order 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 examples, the support pole comprises a pole 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, 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.

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 to second end 30b. of the arm 30 so as to have 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 , circuit box 32 houses the circuitry for measuring the level of soiling 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 circuitry from the surrounding environment and help reduce the risk of malfunction. However, it will be appreciated that other suitable enclosures may be used to house the apparatus circuitry 20, 22.

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 circuitry 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 housing for the 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 may be used to house the circuitry of apparatus 20.

In the examples, the apparatus 20 comprises a battery housing 34 mounted on the base 26. In the examples, the battery housing 34 houses a battery for supplying power to the signal output circuitry of the apparatus 20. In the examples , the battery may also be used to provide power to the metering circuitry of apparatus 20. In the examples, battery housing 34 comprises a Snap-Top battery box model number HM318BKS, manufactured by NOCO®, although it will be appreciated that other suitable battery boxes can be used. In the examples, the battery case 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 may be used.

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 in 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 electricity generation, and the dirt detection apparatus 20, wherein the soil detection apparatus is positioned with respect 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.

In the examples, the apparatus 20 can also be used as a stand-alone unit, for example, to assess the suitability of a potential site for a photovoltaic plant.

Fig. 3 is a schematic circuit diagram of the dirt detecting apparatus 20 according to the exemplary embodiments. In the examples, the dirt detection apparatus 20 comprises a dirt detection circuit for measuring the dirt level of the photovoltaic panel 22.

In the examples, the dirt detection circuit may act as a calculation means operable 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 a comparison means operable to measure the electrical output of the photovoltaic panel in the predetermined operating condition. In the examples, the dirt detection circuits may act as comparison means operable to compare the measured electrical output of the photovoltaic panel in the predetermined operating condition with the reference output value to generate a comparison value. In the examples, the dirty detection circuitry may act as a production means operable to produce a cleaning signal when the comparison value is greater than a cleaning threshold value.

For example, soil detection apparatus can help provide a more reliable indication of soil level. In addition, for example, the need to regularly clean the dirt detection apparatus or the need for complex apparatus to help keep a reference photovoltaic panel in a clean state can be reduced, because the pyranometer can be less affected by dirt than a conventional pyranometer. photovoltaic panel because the irradiance measurement is based on a thermal measurement, for example.

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 an expected electrical output value for the photovoltaic panel in a substantially clean state. By comparing, for example, the measured electrical output of the photovoltaic panel 22 in the predetermined operating condition with the reference output value, an indication of the level of soiling of the photovoltaic panel 22, for example, based on the comparison value, can be obtained. 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 time period after which the photovoltaic panel needs to be cleaned. In the examples, the cleaning signal refers to a level of dirt on the photovoltaic panel 22. Thus, for example, the need to run preset cleaning events of inefficient frequency can also be reduced because the cleaning signal can be issued 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 determine if there is a malfunction of the photovoltaic plant. For example, if the PV plant output is below a malfunction threshold and the comparison value is less than the clean threshold value then a PV plant malfunction signal may be output.

In the examples, the floor 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 circuitry housing 32. However, it will be appreciated that other arrangements may be used to house one or more circuit components.

The operation of the dirt detection circuitry will be described in more detail below.

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 (O/P) pins 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, single pole 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 level of fouling 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.

In the examples, the voltage regulator 40, switch 56, and light sensor 44 are operatively connected to the microcontroller 36 so as to provide electrical power to the microcontroller 36. In the examples, the microcontroller 36 comprises an internal memory, although You will appreciate that an external memory can be used. In the examples, the PV is operatively connected to the input (I/P) pins of microcontroller 36 through shunt resistor 38 and first relay 48 in order to be in electrical communication with microcontroller 36. In the examples, the photovoltaic panel 22 is operatively connected to the battery 46 through the charge controller 42 and the first relay 48 to be able to charge the battery 46, for example, when the detection of dirt is not to be performed. In the examples, the pyranometer 24 is operatively coupled to the input (I/P) pins of the microcontroller 36 through the first relay 48 so as to be in electrical communication with the microcontroller 36. In the examples, the first relay 48 It is a double pole, bipolar relay. As mentioned above, the operation of the components of the dirt detection circuit will be described in more detail below.

Figure 4 is a schematic representation of fouling on a crystalline silicon photovoltaic panel, and Figure 5 is a schematic representation of fouling on a thin film photovoltaic panel. In particular, Figure 4 schematically shows a crystalline silicon photovoltaic panel 58 comprising a plurality of cells crystalline silicon photovoltaics (such as photovoltaic cells 60a, 60b, 60c and 60d). Figure 4 schematically shows a patch of dirt 62 occluding two cells. For example, it is possible for dirt or shadows to block an entire area of one or more of the PV cells on PV panel 58, such as dirt patch 62. This may mean that any cells that are connected in series with those occluded by the dirt patch 62 can be invalidated. For example, those cells may generate little or no electrical current and may be considered fully or partially out of service depending on how dirty they are. Therefore, using the crystalline silicon photovoltaic panel as a reference to detect the level of dirt may give inaccurate results.

Fig. 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 with 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 full 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 as the dirt patch 62 has with respect to crystalline silicon panel 58. In the example of Figure 5, the dirt patch 64 has substantially the same shape and size as the patch of dirt 62 illustrated in Figure 4. However, as the cells of the photovoltaic panel 22 of the examples extend along substantially the entire length of the panel from one side to the other , the risk of an entire area of a single or multiple cells being occluded by a dirt patch, such as dirt patch 64, can be reduced. Therefore, the use of a thin-film PV panel can help improve reliability and reliability. the accuracy of the dirt measurements.

Fig. 6 is a schematic diagram of the pin layout of a microcontroller used in the dirt detection apparatus according to the examples of the disclosure. In particular, Fig. 6 shows a pin layout of the microcontroller 36. In the examples, the microcontroller 36 comprises an Atmega32 40 Pin PDIP model 8-bit microcontroller, produced by Atmel Corporation. However, it will be appreciated that other microcontrollers may be used.

Pins 33 to 40 refer to the 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 pin 10 VDC. XTAL1 pin 13 and XTAL2 pin 12 can be used in connection with an internal inverting oscillator amplifier, for example, for connection to an external oscilloscope for testing if required, or to act as an external clock signal, for example . AREF pin 32 can be used as an 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 (in/out), for example, to provide one or more output signals and/or to program the microcontroller 36.

Figure 7 is a schematic representation of the apparatus for programming the microcontroller 36 of the soil 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). of 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 may be supplied from interface board 68 to microcontroller 36 via pin 10 VDC and pin 11 GND. In the examples, a program written in a suitable programming language may be uploaded from computer 66 to microcontroller 36 via interface board 68 so that the microcontroller may help provide the functionality of the apparatus as described herein. 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 programming the microcontroller could be used. In the examples, the dirt detection circuit comprises an interface port which can be connected to the interface board via a suitable connector mounted on the housing 32. Therefore, in the examples, the operating conditions of the detection apparatus can be modified or adapted as required, 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 dirt detection apparatus. This can help provide a more flexible measurement system for fouling detection.

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 according to the disclosed examples. In particular, in the examples the voltage regulator 40 comprises a voltage regulator circuit as illustrated in Figure 8.

In the examples, the voltage regulator circuit comprises a voltage regulator IC 70, a battery 72, a first capacitor 74, and a second capacitor 76. In the examples, the voltage regulation IC 70 is a voltage regulator IC. positive voltage IC (IC) model number LM7805 manufactured by STMicroelectronics (RTM), with a pin layout as illustrated schematically in the example in Figure 9. In the examples, the battery is a 9-volt battery, for example, a battery PP3, 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 voltage regulator ICs 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 microcontroller 36 via pin 10 VDC and pin 11 GND of microcontroller 36 to be capable of providing a 5V supply.

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 in Figure 10 shows the shunt resistor 38, the pyranometer 24, and a portion of the microcontroller pinout (to aid 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 via pin 31 GND and pin 40 RA0 (ADC0). . More generally, in the examples, the output voltage of pyranometer 24 can be thought of as an irradiance signal that refers to an irradiance level of light incident on pyranometer 24.

In the examples, the shunt resistor 38 is operatively connected to the microcontroller 36 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 via GND pin 31 and PA1 (ADC1) pin 39 in order to measure the voltage across shunt resistor 38. In the examples, shunt resistor 38 comprises a CADDOCK model SR10 shunt resistor Electronics, with a rated power of 1W and a resistance of 0.008W, and with a maximum operating current of 11A. It also works with virtually no derating of the rated load up to a temperature of 70 degrees Celsius, which may make it more suitable for use in arid and desert areas. In the examples, the maximum short-circuit current of the PV panel 22 (for example, model FS-41 15-3) is 1.83 A. Therefore, for example, the electrical output of the PV panel 22, as the short-circuit current of photovoltaic panel 22, can be measured using shunt resistor 38 and calculated by Ohm's law from the voltage input to the second analog-to-digital converter ADC of microcontroller 36. However, it will be appreciated that other options can be used. shunt resistors and photovoltaic panels and measure the electrical output of the photovoltaic panel 22 in other suitable ways, such as by means of an ammeter or a voltmeter.

More generally in the examples, the dirt detection apparatus comprises the shunt resistor 38 arranged to be connectable between the output terminals of the photovoltaic panel 22, in which the measurement means (such as the microcontroller 36) are operable to measure the short circuit current per connection through the shunt resistor 38. In other words, in the examples, the default operating condition is a short circuit current of the photovoltaic panel 22. In other examples, the default operating condition is a position in 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 more complex circuitry to establish the default operating condition. In the examples, the short-circuit current of the photovoltaic panel 22 is substantially proportional to solar irradiation, and variations in solar cell temperature are generally insignificant. For example, in the case of photovoltaic panel 22 (FS-41 15-3), as used in the disclosed examples, the short circuit current may vary by 0.04%/°C compared to the short circuit current under standard test conditions at 25°C. By comparison, a maximum power output of the FS41 13-3 PV panel of examples may change by 0.28%/°C compared to standard test conditions at 25°C. In general, other PV panels and modules have a similar temperature trend dependent on short-circuit current and peak power. Therefore, for example, short-circuit current measurement can provide a more accurate indication of the level of contamination, as well as help simplify the circuitry required to detect the level of contamination.

In the examples, the measured short circuit current of the PV panel 22 that is related to a level of dirt on the panel 22 is compared to an expected short circuit current of the PV 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, from 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 another signal related to a level of soiling can be output, as will be described in more detail below.

Fig. 11 is a schematic diagram of an output signal path of the microcontroller used in the dirt detecting apparatus according to disclosed examples. In the example shown in Figure 11, microcontroller PBO (XCK/TO) pin 1 and GND pin 11 are operable to output a first logic signal, for example, depending on a logic level of 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 may be used. In the examples, pins 1 and 11 of microcontroller 36 may be operatively connected to second relay 50a to allow 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 clean threshold value.

In the examples, microcontroller PB1 pin 2 (T1) and GND pin 11 are operable to output a second logic signal, eg, in dependence on a logic level of 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 logic signals can be used. adequate. In the examples, pins 2 and 11 of microcontroller 36 may be operatively 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 required soon. In the examples, the warning signal is operable to be output when the comparison value is between a warning threshold value and the cleaning threshold value. In the examples, the warning threshold value is less than the clean threshold value. In other examples, the warning signal may be omitted and the third relay 52 is not used.

In the examples, microcontroller PB2 pin 3 (AIN0/INT2) and GND pin 11 are operable to output a third logic signal, eg, in dependence on a logic level of 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 may be used. In the examples, pins 3 and 11 of microcontroller 36 may 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 clean threshold value. In the examples, the third output signal 54a is an idle 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 issued when the comparison value is less than the cleaning threshold value and also less than the warning threshold value. Thus, for example, the latent signal may allow a PV plant operator to determine that a cleaning event does not need to be scheduled and thus may help improve the efficiency of scheduling cleaning events.

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 microcontroller pins could be used. It will also be appreciated that the idle signal, the clean signal and the warning signal may be generated in other suitable ways. Also, in the examples, one or more of the first output signal 50a, the second output signal 52a, and the third output signal 54a may 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 loudspeaker or piezoelectric buzzer via current path 57 with battery 46.

Fig. 12 is a schematic connection diagram of the voltage regulation circuit to the light sensor 44 used in the dirt detecting apparatus 20 according to disclosed examples. As already mentioned, in the examples the soil detection apparatus comprises a light sensor 44. In the examples, the light sensor 44 is operable to detect an illumination level of 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 lighting level may be such that fouling detection is performed during the day, for example.

In the examples, the dirt detection circuit 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 an ST series switch manufactured by Carling Technologies. However, it will be appreciated that any suitable type of switch may be used. In the examples, switch 56 allows manual activation or deactivation of the soil detection measurement. In the examples, as illustrated in Figure 12, the voltage regulator 40 may be in electrical connection to the microcontroller 36 (for example, to the 10 VDC pin and the 30 AVCC pin) through the light sensor 44 and the switch. 56 in order to provide power to the microcontroller 36. However, other suitable connection arrangements could be used in order to provide power to the microcontroller 36.

As already mentioned, in the examples, the battery 46 is arranged to be able to provide power to the apparatus. In the examples, the photovoltaic panel 22 may be in electrical connection with the battery 46 in order 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 in order 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 rate of charge from the photovoltaic panel 22 to the battery 46. In the examples, the charge controller The charge controller 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 dirt detection circuit is operable to perform dirt detection in dependence on a dirty detection control signal, for example, generated by the microcontroller. In the examples, power to microcontroller 36 may be supplied from battery 46, for example, using a suitable voltage regulation circuit. However, in other examples, the microcontroller can be powered from any other suitable power source, such as a 9V battery or regulated mains power. However, the use of one or more batteries may allow the apparatus 20 to operate in remote locations without external support infrastructure.

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 level of soiling 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.

As already mentioned, in the examples, the fouling detection circuit comprises a first relay 48 that 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 Double Pole (DPDT) Relay as a 5V, 8-Pin Relay, Model Number JW2SN-DC5V manufactured by Panasonic. However, it will be appreciated that other types of relays may 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 normally open terminal, and a first normally closed terminal, wherein current can flow between the first common terminal and the first open terminal or the first open terminal. normally closed, 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, where current can flow between the second common terminal and the second open terminal or the second open terminal. normally closed, depending on whether the coil is energized (current flowing through the coil). In other words, for example, the first relay 48 may function as a bipolar type double pole relay.

In the examples, the microcontroller 36 is operatively connected to the coil so as to energize the coil so as to switch the first relay 48. In the examples, the dirt detection control signal comprises a relay control signal. In the examples, the coil terminals are operatively connected to GND pin 11 and PB3 pin 4 (AIN1/OCO) so that the coil can be energized by the control signal from the relay, such as a relay output signal. 5V from the microcontroller 36, for example, to enable the dirt detection apparatus to perform dirt detection or control the dirt detection measurement.

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 issued by 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, such 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 relay control signal from microcontroller 36. In the examples, the first normally closed terminal is connected electrically. operative to the charge controller 42, so that the battery 46 can be charged when the coil is not energized, for example, when the 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 control signal from the relay.

In other examples, pyranometer 24 and shunt resistor 38 could be operatively connected to the normally closed terminal of relay 48, and charge controller 42 connected to a normally open terminal so that battery 46 can be charged when the coil is energized. However, it will be appreciated that other connection arrangements may be used.

In other examples, connection to charge controller 42 may be omitted and other arrangements used to charge battery 46. In addition, it will be appreciated that battery 46 could be omitted with appropriate modifications to the output signals of microcontroller 36, such as output signals 50a, 52a, and 54a.

In the examples, the apparatus 20 is operable to assess the impact of fouling on the output 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 output of the plant more accurately and thus can help power grid management, power distribution and profit forecasting.

It will be appreciated that where a photovoltaic panel or panels are mentioned, one or more photovoltaic modules may be used instead of or in combination with one or more photovoltaic panels. It will also be appreciated that a photovoltaic panel(s) 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 suitable physical configuration, such as having a substantially flat light-receiving surface, or a curved light-receiving surface, for example.

The exemplary apparatus of the disclosure may allow for 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 the reference photovoltaic panel (such as photovoltaic panel 22), with microcontroller 36 programmed as appropriate. In other words, for example, the apparatus of the disclosure can help provide a more flexible and easily adaptable way of determining the level of soiling on a photovoltaic panel.

Although various examples have been described herein, they are provided by way of example only and many variations and modifications of such examples will be apparent to the skilled person and fall within the spirit and scope of the present invention, which is defined in the appended claims and their equivalents.

Claims (13)

1 Dirt detection device, to detect a level of dirt on a photovoltaic panel, the device comprising: a photovoltaic panel adapted to generate an electrical output in response to light incident on the panel and as a function of the level of soiling of the photovoltaic panel; a pyranometer adapted 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 such that the photovoltaic panel and the pyranometer can receive substantially the same level of solar radiation than the other; calculation means adapted 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; measuring means adapted to measure the electrical output of the photovoltaic panel in the predetermined operating condition; comparison means adapted 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 output means adapted to output a cleaning signal when the comparison value is greater than a cleaning threshold value. 2. - Dirt detection apparatus according to claim 1, wherein the output means are adapted to produce a latent signal when the comparison value is less than or equal to the cleaning threshold value. 3. - Dirt detection apparatus according to claim 1 or claim 2, wherein the output means are adapted to emit a warning signal when the comparison value is between a warning threshold value and the threshold value cleaning. 4. - Dirt detection device according to any one of the preceding claims, in which the predetermined operating condition is a photovoltaic panel short-circuit current. 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 adapted to measure the short-circuit current per connection through the shunt resistor. 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, in which the photovoltaic panel can be in electrical connection with the battery to be able to charge the battery. 7. - Dirt detection apparatus according to any one of the preceding claims, comprising a light sensor adapted to detect an illumination level of the light incident on the light sensor, wherein the apparatus is adapted to perform the detection of the level of dirt when the level of illumination is greater than a threshold level of illumination. 8. - Dirt detection apparatus according to claim 7 when it depends on claim 6, in which the photovoltaic panel is adapted to charge the battery when dirt detection is not performed. Dirt detection apparatus according to any one of the preceding claims, wherein the apparatus is adapted to measure the electrical output of the photovoltaic panel at predetermined time intervals to detect a level of dirt on the photovoltaic panel. 10. Dirt detection device according to any one of the preceding claims, wherein the device is adapted to measure the electrical output of the photovoltaic panel for a predetermined duration. 11. - Dirt detection apparatus according to any one of the preceding claims, wherein the photovoltaic panel comprises a plurality of thin-film photovoltaic cells. 12. - Dirt detection apparatus according to any one of the preceding claims, wherein: the apparatus is adapted to generate a classification signal as a function of the comparison value; Y the classification signal is related to an expected output of one or more photovoltaic panels having substantially the same level of dirt as the photovoltaic panel of the apparatus. 13. - Photovoltaic plant, comprising a plurality of photovoltaic panels for generating electricity, the photovoltaic plant comprising a dirt detection device according to any one of the preceding claims, in which the dirt detection device is placed with respect to one or more photovoltaic panels of the photovoltaic plant in such a way that it receives substantially the same dirt as one or more photovoltaic panels of the photovoltaic plant.