CN111628721A - A decision-making method, monitoring system and cleaning system for dust cleaning of photovoltaic modules - Google Patents

Abstract

A photovoltaic module dust cleaning decision-making method, monitoring system and cleaning system. A first photovoltaic module and a second photovoltaic module are preset, and the two are placed in a photovoltaic power station under the same conditions, and the first photovoltaic module is automatically cleaned regularly, 1) Collecting data separately The current and voltage of the first photovoltaic module and the second photovoltaic module are calculated to obtain the accumulation degree of dust; 2) The power generation loss is calculated according to the accumulation degree, and the loss cost is further calculated; 3) If the loss cost is greater than the cleaning cost of the photovoltaic power station, enter the Step 4); if not, compare the accumulation degree with the preset grayscale threshold value, if it exceeds the grayscale accumulation threshold, send an alarm message, and return to step 1); 4) Obtain weather forecast data, according to the amount of precipitation Calculate the expected value of the future precipitation value, if the expected value is less than the preset rainwater threshold, send a cleaning instruction; if not, go back to step 1). The method of the invention judges whether cleaning is necessary according to the accurate data source, avoids human subjectivity, and judges the structure more accurately and efficiently.

Description

A decision-making method, monitoring system and cleaning system for dust cleaning of photovoltaic modules

technical field

The invention relates to the field of photovoltaic modules, in particular to a decision-making method, monitoring system and cleaning system for dust cleaning of photovoltaic modules.

Background technique

At present, the photovoltaic modules are installed on the roof. For the situation that the roof dust accumulates on the surface of the photovoltaic modules, only people can climb to the roof to observe the surface of the photovoltaic modules at a close distance. Cleaning is required.

Due to the accumulation of dust on the surface of photovoltaic modules, it is a continuous, slow and gradual process, which affects the power generation of photovoltaic modules.

In addition, the impact of dust on the surface of photovoltaic modules on the power generation will lead to the inability to maximize the power generation efficiency of photovoltaic modules, and the "hot spot effect" of photovoltaic modules will also be caused in the serious part of the dust accumulation, reducing the service life of the modules. There is no basis for decision-making when cleaning is required.

With the research on dust monitoring on the surface of photovoltaic modules and the judgment of cleaning decision-making timing, some inventions have set up two contrasting photovoltaic modules placed under the same conditions through innovative devices to measure the difference between the working voltage, working current and calculated power of the photovoltaic modules. When the working current or power of the uncleaned component and the current or power of the timely cleaned component reach a certain difference, an instruction or prompt message of the corresponding decision-making mechanism is triggered. The disadvantage is that in the design of the real-time cleaning device that guarantees the placement of photovoltaic modules under the same conditions, the method of cleaning the modules lacks a continuous and stable reliability guarantee. Because most of the solutions are designed to store water in a water tank, cycle the cleaning water, and require external power supply to the system. And there is no comprehensive economic consideration combined with the cleaning cost and cleaning cost of photovoltaic power plants in practical applications.

Some improved inventions have a calculation and comparison strategy combined with cleaning costs, but the disadvantage is that it does not take into account that it may rain one day in the future after just cleaning, and different amounts of rain will dissolve and wash away the surface of photovoltaic modules Different levels of dust, causing the cost of previous cleaning is actually an extra waste.

Another method is to clean the components according to the weather forecast that there will be no rain in the next 5 days, and the cumulative 20-day power generation loss is greater than 80% of the cleaning cost; The data recording and accumulation of rainfall and power increase, the construction of a polynomial mathematical model, and the complex calculation by solving the related linear equations, the precipitation forecast in the future will lead to the loss of power after rain. The final decision is whether to clean.

As mentioned above, in the case of rain on a certain day in the future (this certain day can only be within the last 2 or 3 days in the future, the precipitation value of the weather forecast is accurate, and the deterministic precipitation value can be used, otherwise the precipitation value X If the possible change is large, the possible change range of the corresponding calculated component power loss value f(X) is larger, and the meaning of comparison and reference is lost.) The coefficients in the relevant polynomial mathematical model are derived, subject to the rainfall in a certain period before The statistical reliability of the data of rainfall and power increase has a great influence. The statistical relationship between rainfall and power increase, and random interference will greatly reduce the reliability of this mathematical model. The predicted power loss value after rain may have a higher probability. big deviation. At the same time, the weather forecast can only be combined with the precipitation information in the short-term 2 or 3 days in the future, and the lack of relevant cleaning costs can be combined with the short-, medium- and long-term rainfall, which is unavoidable due to the theoretical principles and mathematical modeling of the invention. insufficient.

In addition, the traditional cleaning method is to manually dry wipe with a broom or mop, or manually drag a water pipe, spray water, and then cooperate with a mop and glass scraper to perform artificial wet cleaning. This method of cleaning the dust on the surface of photovoltaic modules is time-consuming and labor-intensive, and the labor cost of each cleaning is high; at the same time, there are safety hazards such as high-altitude falls and electric shocks for personnel roof cleaning. The new way to clean the dust on the surface of photovoltaic modules is also the operation and maintenance cleaning robot, which uses the roller brush of the operation and maintenance cleaning robot to remove the dust on the surface of the module. However, there is a high one-time investment. In the later operation and maintenance, batteries, brushes, etc. need to be replaced regularly, and accessories, fault maintenance, etc., are replaced at the same time. The operation and maintenance cost is high, which hinders the wider application.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to overcome the above-mentioned defects in the prior art, and propose a decision-making method, monitoring system and cleaning system for dust cleaning of photovoltaic modules, which is easy to implement by combining dust accumulation degree and weather forecast data for cleaning and judgment.

The present invention adopts following technical scheme:

A decision-making method for dust cleaning of photovoltaic components; a first photovoltaic component and a second photovoltaic component are preset, and the two are under the same conditions

It is placed in a photovoltaic power station, and the first photovoltaic module is cleaned regularly. The remaining steps are as follows:

1) Collect the current and voltage of the first photovoltaic module and the current and voltage of the second photovoltaic module respectively, and calculate the dust accumulation degree Dj;

2) Calculate the power generation loss Qs of the photovoltaic power station according to the dust accumulation degree Dj, and further calculate the loss cost Cs according to the power generation loss;

3) Compare the loss cost Cs with the cleaning cost Cc of the photovoltaic power station, if the loss cost Cs is greater than the cleaning cost Cc, go to step 4); if not, compare the accumulation degree Dj with the preset grayscale threshold value, If it exceeds the grayscale threshold, send an alarm message, if not, go back to step 1);

4) Obtain the weather forecast data, calculate the expected value Re of the future precipitation value according to the amount of precipitation, if the expected value Re is less than the preset rainfall threshold, send a cleaning instruction; if not, go back to step 1).

In step 1), the current is the short-circuit current, and the voltage is the maximum open-circuit voltage; the calculation formula of the dust accumulation degree Dj is as follows: Dj=((Voc1-Voc2)/Voc1+(Isc1-Isc2)/Isc1)/ 2×100%, where Voc1 and Isc1 are the maximum open-circuit voltage and short-circuit current of the first photovoltaic module, respectively, and Voc2 and Isc2 are the maximum open-circuit voltage and short-circuit current of the second photovoltaic module, respectively; in this step, the accumulation of dust can also be judged Whether the level Dj is less than the cleaning threshold, if so, issue a cleaning completion instruction.

In step 2), the total power generation loss is the theoretical power generation loss of the photovoltaic power station in the next 15 days Qs=P0×f×H0×15/365×Dj, H0 is the annual effective power generation hours at the location of the photovoltaic power station, P0 is the installed power of the photovoltaic power station, and f is the system efficiency of the photovoltaic power station.

In step 2), the loss cost Cs=Qs×p, and p is the comprehensive electricity price of the electricity generated by the photovoltaic power station.

In the step 4), the expected value Re=S×Maxs(Rs,Rm,Rh)+M×Maxm(Rs,Rm,Rh)+L×Maxl(Rs,Rm,Rh), where S, M , L are the short-term, medium-term and long-term precipitation probability in the future, Maxs() represents the maximum precipitation in the short-term value, Maxm() represents the maximum precipitation in the medium-term value, Maxl() represents the maximum precipitation in the long-term value, Rs , Rm, Rh are the light rain precipitation, moderate rain precipitation and heavy rain precipitation, respectively.

A photovoltaic assembly dust monitoring system; comprising a first photovoltaic assembly, a second photovoltaic assembly, a collection unit, a cleaning control circuit, a power storage unit, a first spray unit, a wiper unit, a communication unit and a monitoring platform; the first photovoltaic assembly The module and the second photovoltaic module are placed under the same conditions and are respectively connected with the power storage unit to charge it; the collection unit is connected with the first photovoltaic module and the second photovoltaic module to collect voltage and current; the spray unit and the wiper unit are installed on the first photovoltaic component; the cleaning control circuit is connected with the power storage unit, the spray unit and the wiper unit to control the timing to clean the first photovoltaic component; the communication unit is connected with the acquisition unit to send voltage and current; the monitoring platform communication unit collects Communication, according to the voltage and current, calculate the dust accumulation degree and loss cost, according to the dust accumulation degree to judge whether to send the cleaning command or alarm information, or according to the loss cost combined with the weather forecast data to determine whether to send the cleaning command.

The first photovoltaic assembly and the second photovoltaic assembly are connected in parallel, and further includes a first switch and a second switch, the first switch is used to switch the communication between the first photovoltaic assembly and the collection unit or the battery, the second The switch is used to switch the communication between the second photovoltaic component and the collection unit or the battery; or the first photovoltaic component and the second photovoltaic component are connected in series, and a switch is also provided, and the switch is connected to the first photovoltaic component and the second photovoltaic component. between two photovoltaic modules.

The first photovoltaic assembly and the second photovoltaic assembly are both polygonal, and the wiper unit is provided with two wipers and a motor connected to them. The two wipers are adapted to the first photovoltaic assembly, and the two wipers are respectively Pressed on the adjacent two sides of the first photovoltaic assembly, the motor drives the two wipers to scrape the surface of the first photovoltaic assembly, and there are blank areas on the adjacent two sides of the first photovoltaic assembly, and the two wipers The non-working states are respectively docked in the blank area.

It also includes a second spray unit. The second spray unit is arranged around the photovoltaic module and the second photovoltaic module, and receives a cleaning command or a cleaning completion command from the photovoltaic module monitoring system according to any one of claims 6 to 8. Turn on or off the spray to the photovoltaic module and the second photovoltaic module.

The second spray unit includes a spray pipe, a number of lifting nozzles and at least one intelligent control valve, the spray pipe is arranged on the periphery of a number of photovoltaic modules, the lifting nozzle is installed on the spray pipe, and the intelligent control valve is installed on the spray pipe. on the pipeline.

As can be seen from the above description of the present invention, compared with the prior art, the present invention has the following beneficial effects:

1. In the method and system of the present invention, a first photovoltaic assembly and a second photovoltaic assembly are set, and the two are placed in a photovoltaic power station under the same conditions, and the first photovoltaic assembly is automatically cleaned at regular intervals, and information such as current and voltage is collected. Combined with weather forecast data to determine whether cleaning is needed, based on accurate data sources to avoid human subjectivity, the judgment is more accurate and efficient.

2. With the method and system of the present invention, the obtained weather forecast related rainfall data is updated from time to time, and the basis for calculation and measurement is always standing at the current point in time, dynamically and closely combining the precipitation and rainfall in the next 15 days for analysis. Judgment; the quantitative calculation of the future precipitation value Re and the comparison of the rainfall threshold R0 are simple and easy to obtain. Compared with the existing technology, it can be considered in a longer term in combination with the weather conditions, and the corresponding component cleaning decisions will be more scientific and reasonable; Simple, practical and practical.

3. In the method and system of the present invention, the accumulation degree of dust is calculated according to the maximum open-circuit voltage and short-circuit current, which is used as the calculation basis for the loss cost, which is used as one of the judgment conditions for realizing cleaning, and the expected value of precipitation is used as another judgment condition. Combining the two judgment conditions to determine whether to clean or not, the judgment structure is more reliable and accurate.

4. In the method and system of the present invention, if the two judgment conditions of the loss cost and the expected value of precipitation are not met, it is judged whether to send an alarm message according to the degree of dust accumulation, so as to inform the user of the relevant degree of dust accumulation; degree to determine whether the cleaning of the second photovoltaic module is completed.

5. In the method and system of the present invention, the relevant information of the first photovoltaic module and the second photovoltaic module is collected by the collection unit, and the first spray unit and the wiper unit are controlled by the cleaning control circuit to periodically clean the first photovoltaic module, and the storage The electric unit is charged by the first photovoltaic assembly and the second photovoltaic assembly, and supplies power to the cleaning control circuit and other circuits, and the monitoring structure is simple, the components are few, the cost is low, and the realization is easy.

6. In the method and system of the present invention, a first switch and a second switch are arranged between the collection unit and the first photovoltaic component and the second photovoltaic component; or a switch is arranged so as to perform the collection operation or the charging operation. switch, the circuit is simple.

7. In the method and system of the present invention, a monitoring platform is set up to receive collected information, calculate the dust accumulation degree of dust, etc., form a database summary, and can visually present various graphs, histograms and other graphs. Relevant data and charts can be synchronously transmitted and displayed on the customer's mobile phone APP or on the customer's photovoltaic power plant operation and maintenance management system cloud platform.

8. In the cleaning system of the present invention, the cleaning system can receive the cleaning instruction from the monitoring system or after the cleaning is completed, automatically control the opening or closing of the cleaning, and use the cleaning pipeline and the lifting nozzle to make full use of the connection point of the cleaning water pipe that has been laid on the roof. , In the roof photovoltaic module area, reasonably arrange the sprinkler irrigation points; because the lifting nozzle can be automatically raised and lowered (no shadow blocking problem will be formed in the module area), the angle can be adjusted, and within the range of the range, a rain curtain can be formed to reasonably cover the surface of the module. Small and large water droplets dissolve dust deposits on the component surface.

9. The cleaning system of the present invention is also provided with a drainage device. Due to the surface tension of the water on the horizontal lower end frame of the solar cell, the water will enter the leading end of the capillary water absorption pipe, and be discharged through the upper transverse part, the middle part, and the lower transverse part. Or it can be discharged through the drainage outlet of the upper horizontal part and the middle part, which has high efficiency, no manual operation, and can adapt to the accumulated water of different rainfall. In addition, the gap between the inclined section of the middle part and the frame gradually increases from top to bottom, so that the water flows smoothly, and it is better to keep the drainage device and the side of the frame dry. Border width dimension.

10. The cleaning system of the present invention can solve the problem of low-cost cleaning of dust on the surface of photovoltaic modules; at the same time, because personnel climbing operations are reduced, the safety risks faced by personnel frequently going up and down the roof are reduced, and personnel, tools and equipment are directly reduced. Moving on the roof may cause damage and damage to the roof color steel tile, reducing the risk of electric shock for personnel in the roof photovoltaic power station; in addition, the sprayed water droplets effectively reduce the temperature of the surface of the module, which can make the photovoltaic effect of the photovoltaic module. The power generation efficiency of the photovoltaic module body is improved; the evaporation of water on the roof reduces the temperature of the roof color steel tile, and also directly reduces the room temperature inside the workshop.

Description of drawings

FIG. 1 is a connection diagram of a collection unit and a photovoltaic module of the present invention;

FIG. 2 is a schematic diagram of cleaning the first photovoltaic module;

Fig. 3 is the flow chart of the method of the present invention;

Fig. 4 is the main module diagram of the monitoring system of the present invention;

5 is a schematic diagram of the communication between the intelligent control valve of the cleaning system of the present invention and the monitoring background;

6 is a structural diagram of the second spray unit of the present invention;

Figure 7 is a structural diagram of a drainage device;

Fig. 8 is the structure diagram of the lifting nozzle of the present invention;

Fig. 9 is the working diagram of the lifting nozzle of the present invention;

FIG. 10 is a connection diagram of the collection unit and the photovoltaic module according to the present invention (Embodiment 2);

FIG. 11 is a connection diagram of the collection unit and the photovoltaic module according to the present invention (Embodiment 2);

in:

10, photovoltaic module, 11, first photovoltaic module, 12, second photovoltaic module, 13, frame, 14, solar cell, 20, collection unit, 21, first switch, 22, second switch, 23, switch, 24, resistor, 30, cleaning control circuit, 40, power storage unit, 50, first spray unit, 60, wiper unit, 61, wiper, 62, blank area, 80, communication unit, 90, monitoring platform, 100, drainage device, 110, upper transverse part, 120, middle part, 130, lower transverse part, 160, second spray unit, 161, spray pipe, 162, lift sprinkler, 163, housing, 164, Lifting head, 165, intelligent control valve.

Detailed ways

The present invention will be further described below through specific embodiments.

Referring to FIG. 3 , a decision-making method for dust cleaning of photovoltaic modules, a first photovoltaic module 11 and a second photovoltaic module 12 are preset, placed in a photovoltaic power station under the same conditions, and the first photovoltaic module 11 is cleaned regularly. Placement under the same conditions means that the angles and positions of the photovoltaic modules are the same. The remaining steps are as follows:

1) Collect the current and voltage of the first photovoltaic assembly 11 and the current and voltage of the second photovoltaic assembly 12 respectively, and calculate the dust accumulation degree Dj;

2) Calculate the power generation loss Qs of the photovoltaic power station according to the dust accumulation degree Dj, and further calculate the loss cost Cs according to the power generation loss;

3) Compare the loss cost Cs with the cleaning cost Cc of the photovoltaic power station, if the loss cost Cs is greater than the cleaning cost Cc, go to step 4); if not, compare the accumulation degree Dj with the preset grayscale threshold value, If it exceeds the grayscale threshold, send an alarm message, if not, go back to step 1);

4) Obtain the weather forecast data, calculate the expected value Re of the future precipitation value according to the amount of precipitation, if the expected value Re is less than the preset rainfall threshold value RO, send a cleaning instruction; if not, go to step 1).

In step 1), the current is the short-circuit current, and the voltage is the maximum open-circuit voltage; the calculation formula of the dust accumulation degree Dj is as follows: Dj=((Voc1-Voc2)/Voc1+(Isc1-Isc2)/Isc1)/2×100%, where Voc1 and Isc1 are respectively the maximum open-circuit voltage and short-circuit current of the first photovoltaic assembly 11 , and Voc2 and Isc2 are respectively the maximum open-circuit voltage and short-circuit current of the second photovoltaic assembly 12 . In this step, it can also be judged whether the dust accumulation degree Dj is smaller than the cleaning threshold, and if so, a cleaning completion instruction is issued, which means that the surface of the second photovoltaic module 12 has been cleaned.

In this step, the frequency of the data collection action can be consistent with the frequency of cleaning the first photovoltaic module 11 every day, which is performed after the first photovoltaic module 11 is cleaned, or can be set as required to increase the frequency of detection and collection, which is not limited. .

Further, in this step, the collected data is uploaded to the monitoring platform in the background for calculation processing, statistical analysis, and a database summary is formed, which can visually present various graphs, histograms and other graphs. Relevant data and charts can be synchronously transmitted and displayed on the customer's mobile phone APP or on the customer's photovoltaic power plant operation and maintenance management system cloud platform.

In the present invention, the existing grayscale formula can also be used to calculate the dust accumulation degree, which is not limited to this.

In step 2), the total power generation loss is the theoretical power generation loss of the photovoltaic power station in the next 15 days Qs = P0 × f × H0 × 15/365 × Dj, where H0 is the annual effective power generation hours at the location of the photovoltaic power station (for example: a certain area). The annual effective power generation hours is 1150 hours), P0 is the installed power of the photovoltaic power station, f is the system efficiency of the photovoltaic power station, and the value can be 80%. In practical applications, it is not limited to the theoretical power generation loss of 15 days, but can also be set to 10 days, 20 days, etc. according to the actual situation.

Further, according to the theoretical power generation loss Qs for the 15 days, calculate the corresponding loss cost Cs = Qs × p, p is the comprehensive electricity price of the electricity generated by the photovoltaic power station, and the comprehensive electricity price = the desulfurized coal electricity price that is sent to the national grid. × Internet access ratio + State grid retail electricity price of the user's self-generated and self-consumption portion × Self-generated self-consumption ratio.

In step 3), the historical data of the photovoltaic power station can be cleaned by manual cleaning or other methods in the past, and the cost Cc required for each cleaning can be obtained according to statistics. The loss cost Cs is compared with the previous cost Cc for each cleaning of the photovoltaic power station.

Among them, the dust accumulation threshold D0 can be preset as 3%, 5%, and 10%, which can be selected according to actual needs. Alarm information can be sent to the customer's display terminal.

In step 4), combined with the future local short, medium and long-term weather forecast information, the future local short, medium and long-term weather forecast information is used as another judgment condition for judging whether the photovoltaic modules need to be cleaned. The rainfall threshold R0 can be preset, for example, 10mm.

In practical applications, by connecting the weather forecast data of the China Meteorological Data Network and the local meteorological bureau, the update frequency of the live weather interface is once every hour, and the weather forecast interface is updated three times a day, so that a stable and reliable source of local weather data can be obtained. .

The present invention fully considers the possibility of short, medium and long-term local precipitation in the future, starts from the principle of weather forecast, makes full use of and combines the characteristics of weather forecast, and sets the probability ratio of relevant parameters. For example, the range of short-term, mid-term, and long-term values of weather forecasts is based on the "National Meteorological Department's length of weather forecast timeliness is usually divided into three types: short-term weather forecasts (2 to 3 days), medium-term weather forecasts ( 4 to 9 days), long-term weather forecast (10 to 15 days)”. The corresponding accuracy of the precipitation forecast for the next 2 to 3 days is the highest. The probability ratio is set to 90% based on the accuracy of the weather forecast. The probability of M is 60%, and the probability of L is 30%. ; and the forecast reliability of precipitation in weather forecasts for more than 15 days is already very low, so it is no longer included in the probability ratio of quantitative analysis. At the same time, it can also correspond to the calculation of the total power generation loss caused by the accumulation of dust in the photovoltaic power station in the next 15 days.

In the quantitative calculation and analysis of the rainfall values in the next 15 days, the mathematical model fitting is carried out for the rainfall values of heavy, moderate and light rain, so that it can be easily applied in practice. According to the definition of light rain, moderate rain, heavy rain and heavy rain in the relevant weather forecast of the National Meteorological Department, such as: light rain is the daily precipitation of 1mm to 10mm, moderate rain is the daily precipitation of 10.1mm to 25mm, heavy rain is the daily precipitation of 25.1 mm From mm to 50mm, in the modeling of this mathematical model, the median is taken for the specific values of heavy, medium and light rain, which is more convenient for statistical calculation of probability.

The dust on the surface of photovoltaic modules is washed by rainwater, not only the total amount of precipitation should be considered, but also the intensity of precipitation should be considered. In the case of the same total precipitation value, the effect of short-term heavy precipitation on the dissolution and scouring of dust on the surface of photovoltaic modules will be greatly improved. Therefore, we need to pay more attention to the maximum precipitation intensity in a period of time, which is to take the maximum value in the mathematical model. By optimizing the short, medium and long term, the maximum precipitation amount is taken within the respective probability intervals to consider the actual effect of the precipitation intensity on the dissolving and scouring of dust on the surface of the module, so that the decision analysis can be better approached in reality.

Expected value Re=S×Maxs(Rs,Rm,Rh)+M×Maxm(Rs,Rm,Rh)+L×Maxl(Rs,Rm,Rh), Maxs() represents the maximum precipitation in the short-term value, Maxm( ) represents the maximum precipitation in the medium-term value, Maxl() represents the largest precipitation in the long-term value, Rs, Rm, Rh are the light rain precipitation, the moderate rain precipitation and the heavy rain precipitation, respectively. For example: the maximum precipitation Maxs(Rs, Rm, Rh) for 2-3 days in the short term, if the second day is light rain and the third day is moderate rain, the maximum precipitation is 17.5mm; the maximum precipitation in the long-term value Maxl( Rs, Rm, Rh), assuming heavy rain from the tenth day to the 15th day, the maximum value is 37.5, and so on.

The rainfall threshold R0 is due to the use of the photovoltaic module frame with the module surface water guiding device, so that the R0 value can be greatly reduced. The specific value will vary depending on the slope of the photovoltaic modules actually installed on the roof and the installation method (horizontal, vertical) of the modules. Different, the threshold value R0 can be determined scientifically and rationally, without human subjective factors.

The relevant rainfall data of the weather forecast is updated from time to time, and the basis for calculation and measurement is always standing at the current time point, dynamically and closely combining the precipitation and rainfall in the next 15 days for analysis and judgment. The quantitative calculation of the future precipitation value Re and the comparison of the rainwater threshold R0 are simple and easy to obtain, which can be considered in the longer term in combination with the weather conditions, and the corresponding component cleaning decisions will also be more scientific and reasonable; simple and practical, in line with reality.

Referring to FIG. 4 , the present invention also proposes a photovoltaic component monitoring system, including a first photovoltaic component 11 , a second photovoltaic component 12 , a collection unit 20 , a cleaning control circuit 30 , a power storage unit 40 , a first spray unit 50 , a rain The scraping unit 60, the communication unit 80 and the monitoring platform 90; the first photovoltaic assembly 11 and the second photovoltaic assembly 12 are placed under the same conditions and are respectively connected to the power storage unit 40 to charge it; the collection unit 20 is connected to the first photovoltaic assembly 11 Connected with the second photovoltaic assembly 12 to collect voltage and current; the spray unit and the wiper unit 60 are installed on the first photovoltaic assembly 11; the cleaning control circuit 30 is connected to the power storage unit 40, the first spray unit 50 and the wiper The unit 60 is connected to control the timing of cleaning the first photovoltaic assembly 11; the communication unit 80 is connected to the collection unit 20 to send voltage and current; the monitoring platform 90 communicates with the communication unit 80, and calculates the degree of accumulation of dust and the cost of loss according to the voltage and current , according to the accumulation degree of dust to determine whether to send a cleaning command or alarm information, or to determine whether to send a cleaning command according to the loss cost combined with weather forecast data.

Referring to FIG. 2 , the first photovoltaic assembly 11 and the second photovoltaic assembly 12 are solar cell sheets of the same size and shape, and their installation positions and angles are kept the same for comparison. Under the condition that the monitored data is satisfied, the first photovoltaic module 11 and the second photovoltaic module 12 are connected in parallel to charge the power storage unit 40. The power storage unit 40 may have its own charge and discharge controller, and the charge and discharge controller controls the charge and discharge of the battery. , in order to ensure that the battery is not overcharged, not deeply discharged, and to ensure the service life of the battery.

The first spray unit 50 is disposed on the top or side of the first photovoltaic assembly 11 , and is used for spraying cleaning water to the first photovoltaic assembly 11 . It consists of pipes and water sprinklers (not shown in the figure), which can be connected to municipal water pipes or to cleaning systems with water already installed on the roof. The end of the pipeline of the first spray unit 50 is installed with at least one micro-spray water nozzle, and the water inlet end of the pipeline is installed with a solenoid valve, which is used to control the opening or closing of the pipeline. The solenoid valve is powered by the power storage unit 40 .

The wiper unit 60 includes two wipers 61 and a motor connected thereto, the two wipers 61 are adapted to the first photovoltaic assembly 11 , and the two wipers 61 are respectively installed on the top and the top of the first photovoltaic assembly 11 . On the side, the two wipers 61 are controlled by the motor to perform the cleaning action. The layout of the two wipers is not limited to this, and can also be installed on both sides of the first photovoltaic assembly 11 or on the bottom and sides, that is, the two wipers are respectively installed on adjacent sides of the first photovoltaic assembly 11. 61 are respectively pressed against the surface of the first photovoltaic module, and the motor drives the two wipers 61 to wipe the surface of the first photovoltaic module 11. Further, after the surface of the first photovoltaic module 11 is sprayed with water, the motor drives the two wipers 61 to form a 1/4 The fan-shaped area scrapes the first photovoltaic assembly 11 .

Further, the first photovoltaic assembly and the second photovoltaic assembly are square, but not limited to this, and may also be rectangular, pentagon or other according to different usage scenarios, that is, the first photovoltaic assembly and the second photovoltaic assembly. Components are polygons. There are blank areas 62 on the adjacent two sides of the first photovoltaic module 11; wherein, the reserved blank area 62 is used to park the wiper 61, so that the wiper unit will not block the lighting of the cells in the photovoltaic module when it is not working , that is, the two wipers 61 are respectively parked in the blank area 62 in a non-working state, and the width of the blank area 62 is larger than the width of the wiper blade 61 .

The cleaning control circuit 30 can use a controller with timing and delay functions to control the cleaning of the first photovoltaic module 11 according to a preset time interval, firstly controlling the first spray to act first, and then the two wiper units are divided into first, post action. The cleaning control circuit 30 can be a commercially available PM4H-A, which can set multi-range timing, and can realize the functions of timing and delay start.

The principle of regular cleaning is as follows:

The cleaning control circuit 30 controls the solenoid valve of the first spray unit 50 to open, and the water spray head micro-spraying at the end of the pipe sprays cleaning water to the first photovoltaic assembly 11 .

At the same time, one of the motors of the wiper unit 60 is controlled to work, and the corresponding wiper is attached to the surface glass of the first photovoltaic module 11 and wipes in a quarter-circle fan plane. After several times of scraping, the homing is stopped; then another motor is controlled to work, so that the corresponding wiper wiper partially scrapes the surface glass of the first photovoltaic module 11 several times.

The successive actions of the above two groups of wipers are cycled back and forth. After two to three cycles, the cleaning process is completed, and the cleaning control circuit 30 resets and waits for the next command to be activated again. For example: the time interval for reactivation is set to be between 7:00 and 19:00, every 30 minutes or 2 hours.

The acquisition unit 20 can use a DC voltage and current acquisition module to collect the maximum open circuit voltage and circuit current of the two groups of photovoltaic modules, for example, NX100D-T, which has 8 channels of independent AD synchronous sampling.

1, the present invention is further provided with a first switch 21 and a second switch 22, the first switch 21 is used to switch the communication between the first photovoltaic assembly 11 and the collection unit 20 or the power storage unit 40, the The second switch 22 is used to switch the communication between the second photovoltaic assembly 12 and the collection unit 20 or the power storage unit 40 . That is, for the first switch 21, when the signal is to be collected, the first switch 21 is controlled to turn on the circuit between the first photovoltaic module 11 and the collection unit 20, and when the power storage unit 40 is to be charged, the first switch 21 is controlled The changeover switch 21 turns on the circuit between the first photovoltaic assembly 11 and the power storage unit 40 . The second switch 22 operates in synchronization with the first switch 21 .

Specifically, the first switch 21 and the second switch 22 can be implemented by common switches such as a single-pole double-throw switch or an electromagnetic relay, or the first switch 21 and the second switch 22 can be implemented by a double-pole double-throw switch accomplish. The first switch 21 and the second switch 22 can be controlled by the acquisition unit 20, and the acquisition unit can simultaneously, synchronously, and real-time acquire characteristic data such as voltage and current of two or more sets of photovoltaic modules.

In the present invention, the communication unit 80 is used for sending the collected information, the dust accumulation degree Dj, etc. to the monitoring platform 90 or other terminal devices. The communication unit 80 can use one or more of a WIFI module, an RS485 module, a 433M module, an Ethernet module or an RTU data module to meet different data transmission requirements.

The monitoring platform 90 of the present invention is connected to data such as voltage and current, calculates the dust accumulation degree and loss cost according to the aforementioned decision-making method, and judges whether to send a cleaning completion instruction or alarm information according to the dust accumulation degree, or according to the loss cost combined with the weather forecast The data determines whether to send a cleaning command.

The monitoring platform 90 also includes the following functional modules:

The data storage module classifies and saves the received information such as current, voltage, and dust accumulation.

In the historical data query module, the user can call out the data of a certain month, a certain day or even a certain moment in the past to view it, or choose to only view the cleaning time of a certain day.

The curve analysis module summarizes all the data into the dust accumulation degree - the reduction rate of photovoltaic module power generation performance, and the change curve with the date (day, week, month), which is convenient for users to observe.

With the data export function, users can call up and display data to other terminals or platforms such as mobile APPs, or print them as needed.

The command linkage module cooperates with the use of the spray unit and the drainage device 100 on the roof of the photovoltaic power station. When it is judged that cleaning is required, the photovoltaic module cleaning system can be activated to automatically remove dust on the surface of the photovoltaic module.

The dust accumulation degree prompting module will issue a prompt message or an alarm message when the obtained dust accumulation length Dj exceeds the preset dust accumulation length threshold under the condition that the cleaning conditions are not met.

The programmable fine-tuning module can correct and adjust the parameters of the system according to the actual situation to better adapt to the actual application environment.

The system of the invention can realize the monitoring of the dust on the surface of the photovoltaic modules of the photovoltaic power station and the intelligent decision-making of the cleaning timing.

5 to 9, the present invention also provides a photovoltaic module cleaning system, based on the above photovoltaic module cleaning decision-making method or photovoltaic module monitoring system, it is further provided with several photovoltaic modules 10, and also includes a second spray unit and the like. The second spray unit is arranged around the photovoltaic assembly 10 and the second photovoltaic assembly, and is used to receive a cleaning command to control the opening of the spray to the photovoltaic assembly 10 and the second photovoltaic assembly 12, or to receive a cleaning command to control the closing of the photovoltaic assembly 10. and frequency spraying of the second photovoltaic module 12 .

Wherein, the second spray unit includes a spray pipe 161 , a plurality of lifting nozzles 162 and at least one intelligent control valve 165 , the spray pipe 161 is arranged on the outer periphery of a plurality of photovoltaic modules 10 , and the plurality of lifting nozzles 162 are installed on the spray pipe 161 , The intelligent control valve 165 is installed in the spray pipe 161, and can receive a cleaning command or a cleaning completion command. The intelligent control valve can adopt an intelligent solenoid valve, which is a solenoid valve integrated with a battery, a wireless communication module and a controller, for example: COCON IEV series intelligent solenoid valve.

Specifically, the plurality of photovoltaic assemblies 10 are installed on the roof of the photovoltaic power station, are evenly distributed obliquely, and can be divided into several rows, each row has several columns, and each column has a plurality of photovoltaic assemblies 10 . The spray pipe 161 is provided with a communicating main pipe and several branches, and an intelligent control valve 165 is arranged on the main pipe. Each row of photovoltaic modules corresponds to a branch, each branch is provided with several branches, the branches correspond to at least one column (preferably two columns) of photovoltaic modules, and each branch is provided with at least one elevating nozzle 162 .

Referring to FIGS. 9 and 10 , the elevating spray head 162 can adopt a conventional structure, including a casing 163 and a lifting head 164 . The lifting head 164 is installed in the casing 163 and can rise relative to the casing 163 under the action of water pressure And rotate, so as to achieve rotating spray.

Further, a drainage device 100 is also included, and the drainage device 100 is installed on the bottom side of the photovoltaic module 10 . The photovoltaic assembly 10 includes solar cells 14 and a frame 13 surrounding the solar cells 14 . The drainage device 100 includes an upper transverse portion 110, a middle portion 120 and a lower transverse portion 130 which are connected in sequence. The inner surface of the drainage device 100 is provided with a water groove, and the water groove extends from the front end of the upper transverse portion 110 to the lower transverse portion. At the end, there are multiple water troughs and are arranged side by side along the width direction of the drainage device. The drainage device 100 is buckled on the frame 13 of the photovoltaic module 10 , and the part of the water trough that is against the surface of the frame 13 is surrounded by the surface of the frame 13 . Capillary suction pipe. The structure of the drainage device 100 is not limited to this.

Due to the water surface tension of the horizontal lower end frame of the solar cell 14, water will enter the front end of the capillary water absorption pipe, and be discharged through the upper transverse portion 110, the middle portion 120, and the lower transverse portion 130, or through the upper transverse portion 110, the middle portion 120. The drainage outlet is discharged, the efficiency is high, and no manual operation is required, and it can adapt to the stagnant water of different rainfall.

In this system, one or more monitoring systems can be placed on different roofs and different areas of the same roof for monitoring, and corresponding intelligent control valves 165 can be set according to the actual operating environment of the photovoltaic power station. For example, the building of a factory faces the logistics freight yard, which is different from the dust pollution of other roofs; or a certain section of a workshop belongs to the grinding area, and the roof of this area may have a small amount of dust escaping to the roof. If the photovoltaic modules in the area are polluted, a monitoring device can be installed in the area, and the monitoring device corresponds to the intelligent solenoid valve to control the cleaning pipeline in this part of the area. Set up unified monitoring devices in other environmental areas, and install corresponding intelligent solenoid valves in pairs to control the cleaning pipelines in other areas. Multiple sets of intelligent solenoid valves are networked by number and paired with corresponding monitoring devices, which can realize the perfect combination of large-area monitoring and cleaning and local monitoring and cleaning. The working principle of the system is as follows: when the intelligent control valve 165 receives the cleaning command, the spray pipe 161 is opened, and the municipal tap water flows through the spray pipe 161 and is sent to the lifting nozzle 162, and the lifting head 164 of the lifting nozzle 162 rises and rotates to spray , forming a rain curtain, water flows to the surface of the cleaning photovoltaic module 10, that is, the surface of the second photovoltaic module 12, dissolves the dust on the surface of the photovoltaic module, and the water-cement mixture is smoothly discharged through the drainage device 100 to ensure the drying of the side of the frame 13. During the cleaning process, when The monitoring background monitors that the dust accumulation degree of the second photovoltaic module 12 is less than the cleaning threshold, which means that the surface of the second photovoltaic module 12 and other photovoltaic modules 10 of the photovoltaic power station represented by it has been cleaned, and then the cleaning completion command is sent to the intelligent control valve. 165. The intelligent control valve 165 controls the spray pipe 161 to close.

Embodiment 2

A decision-making method, monitoring system and cleaning system for dust cleaning of photovoltaic components, the main steps and structures of which are the same as those of the first embodiment, the difference is that the first photovoltaic component 11 is connected with the second photovoltaic component 12 in series. In the photovoltaic module monitoring system, a switch 23 is provided, which is connected between the first photovoltaic module 11 and the second photovoltaic module 12 . Referring to FIG. 10 , the first photovoltaic assembly 11 and the second photovoltaic assembly 12 are respectively connected with the collection unit 20 . One end of the power storage unit 40 is connected to one end of the first photovoltaic assembly 11 , the other end is connected to one end of the second photovoltaic assembly 12 , and the switch 23 is connected between the other end of the first photovoltaic assembly 11 and the other end of the second photovoltaic assembly 12 .

The switch 23 can be controlled by the acquisition unit 20. When the switch is turned off, the acquisition unit 20 can detect the open-circuit voltage and short-circuit current of the first photovoltaic assembly 11 and the second photovoltaic assembly 12. When the switch is turned on, the first photovoltaic The assembly 11 and the second photovoltaic assembly 12 charge the power storage unit 40 .

In this embodiment, referring to FIG. 11 , a resistor 24 can also be connected in series with the other ends of the first photovoltaic assembly 11 and the second photovoltaic assembly 12 respectively. When the switch is turned off, the collection unit 20 can detect the first photovoltaic assembly 11 and the operating voltage and operating current of the second photovoltaic assembly 12 . The working current and working voltage are replaced by the open-circuit voltage and the short-circuit current, respectively, and the calculation formula of the dust accumulation degree Dj remains unchanged, and the dust accumulation degree of the second photovoltaic module 12 can also be obtained.

The above are only specific embodiments of the present invention, but the design concept of the present invention is not limited to this, and any non-substantial modification of the present invention by using this concept should be regarded as an act of infringing the protection scope of the present invention.

Claims (10)

1. A photovoltaic module dust cleaning decision method is characterized by comprising the following steps: presetting a first photovoltaic module and a second photovoltaic module, placing the first photovoltaic module and the second photovoltaic module in a photovoltaic power station under the same condition, cleaning the first photovoltaic module at regular time, and carrying out the following steps:

1) respectively collecting the current and the voltage of the first photovoltaic module and the current and the voltage of the second photovoltaic module, and calculating to obtain the dust accumulation degree Dj;

2) calculating the power generation loss Qs of the photovoltaic power station according to the dust accumulation degree Dj, and further calculating the loss cost Cs according to the power generation loss;

3) comparing the loss cost Cs with the cleaning cost Cc of the photovoltaic power station, and if the loss cost Cs is greater than the cleaning cost Cc, entering the step 4); if not, comparing the accumulation degree Dj with a preset accumulated gray level threshold, if the accumulation degree Dj exceeds the accumulated gray level threshold, sending alarm information, and if not, returning to the step 1);

4) acquiring weather forecast data, calculating an expected value Re of a future rainfall value according to the rainfall, and sending a cleaning instruction if the expected value Re is smaller than a preset rainfall threshold; if not, returning to the step 1).

2. The method for making a decision on cleaning a photovoltaic module with dust according to claim 1, wherein: in the step 1), the current is a short-circuit current, and the voltage is a maximum open-circuit voltage; the dust accumulation degree Dj is calculated as follows: dj ═ ((Voc1-Voc2)/Voc1+ (Isc1-Isc2)/Isc1)/2 × 100%, where Voc1, Isc1 are the maximum open-circuit voltage and short-circuit current of the first photovoltaic module, respectively, and Voc2, Isc2 are the maximum open-circuit voltage and short-circuit current of the second photovoltaic module, respectively; in this step, it is also determined whether the dust accumulation degree Dj is smaller than a cleaning threshold, and if so, a cleaning completion instruction is issued.

3. The method for making a decision on cleaning a photovoltaic module with dust according to claim 1, wherein: in the step 2), the total power generation loss is theoretical power generation loss Qs of the photovoltaic power station for 15 days in the future, wherein the theoretical power generation loss Qs is P0 XfXH 0X 15/365 XDj, H0 is annual effective power generation hours of the photovoltaic power station, P0 is installed power of the photovoltaic power station, and f is system efficiency of the photovoltaic power station.

4. The method for making a decision on cleaning a photovoltaic module with dust according to claim 1, wherein: in the step 2), the loss cost Cs is Qs × p, and p is a comprehensive electricity price sold by the generated energy of the photovoltaic power station.

5. The method for making a decision on cleaning a photovoltaic module with dust according to claim 1, wherein: in the step 4), the expected value Re is sxmaxs (Rs, Rm, Rh) + mxmaxm (Rs, Rm, Rh) + lxmaxl (Rs, Rm, Rh), where S, M, L are the future short, medium, and long-term precipitation probabilities, respectively, Maxs () represents the maximum precipitation amount in the short-term value, Maxm () represents the maximum precipitation amount in the medium-term value, Maxl () represents the maximum precipitation amount in the long-term value, and Rs, Rm, Rh are the small, medium, and large precipitation amounts, respectively.

6. A photovoltaic module dust monitoring system which characterized in that: the device comprises a first photovoltaic assembly, a second photovoltaic assembly, a collecting unit, a cleaning control circuit, an electric power storage unit, a first spraying unit, a wiper unit, a communication unit and a monitoring platform; the first photovoltaic module and the second photovoltaic module are placed under the same condition and are respectively connected with the power storage unit to charge the power storage unit; the collecting unit is connected with the first photovoltaic module and the second photovoltaic module to collect voltage and current; the spraying unit and the rain scraping unit are arranged on the first photovoltaic module; the cleaning control circuit is connected with the power storage unit, the spraying unit and the wiper unit to control the cleaning of the first photovoltaic module at regular time; the communication unit is connected with the acquisition unit to send voltage and current; the monitoring platform communication unit collects communication, calculates the accumulation degree and loss cost of dust according to voltage and current, judges whether to send a cleaning finishing instruction or alarm information according to the accumulation degree of the dust, or judges whether to send a cleaning instruction according to the loss cost and weather forecast data.

7. The photovoltaic module dust monitoring system of claim 6, wherein: the photovoltaic system comprises a first photovoltaic assembly, a second photovoltaic assembly, a first change-over switch and a second change-over switch, wherein the first photovoltaic assembly is connected with the second photovoltaic assembly in parallel; or the first photovoltaic module and the second photovoltaic module are connected in series, and a change-over switch is further arranged and connected between the first photovoltaic module and the second photovoltaic module.

8. The photovoltaic module dust monitoring system of claim 6, wherein: first photovoltaic module, second photovoltaic module are the polygon, the windscreen wiper unit is equipped with two wipers and the motor of being connected with it, two wipers with first photovoltaic module mutual adaptation, this two wipers press respectively and paste in first photovoltaic module's adjacent both sides, motor drive two wipers first photovoltaic module surface of scraping, first photovoltaic module's adjacent both sides still are equipped with blank area, two wipers do not operating condition stop respectively in blank area.

9. The utility model provides a photovoltaic module dust cleaning system is equipped with a plurality of photovoltaic module, its characterized in that: the photovoltaic module monitoring system further comprises a second spraying unit, wherein the second spraying unit is arranged around the photovoltaic module and the second photovoltaic module and used for receiving a cleaning command or a cleaning completion command of the photovoltaic module monitoring system of any one of claims 6 to 8 to start or stop spraying the photovoltaic module and the second photovoltaic module.

10. The photovoltaic module dust cleaning system of claim 9, wherein: the second spray unit comprises a spray pipeline, a plurality of lifting spray heads and at least one intelligent control valve, the spray pipeline is arranged on the periphery of the photovoltaic modules, the lifting spray heads are installed on the spray pipeline, and the intelligent control valve is installed on the spray pipeline.

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