Photovoltaic panel automatic cleaning device and partition intelligent cleaning control method

Abstract

An automatic cleaning device for photovoltaic panels and a partitioned intelligent cleaning control method, comprising a track mechanism, a walking trolley, a water spraying mechanism, a main beam, a plurality of spray head units and a lifting mechanism, the main beam is fixed on the walking trolley and spans the width direction of the photovoltaic panel; a plurality of spray head units are arranged at intervals along the length direction of the main beam, each spray head unit is connected with the main beam through the lifting mechanism, and each spray head unit is integrated with a pressure sensor and a flow sensor; the water supply mechanism comprises a cleaning liquid tank, a clean water tank, a water pump, a switching valve and a proportional regulating valve, the inlet of the switching valve is communicated with the outlet of the water pump, and the two outlets of the switching valve are respectively communicated with the cleaning liquid tank and the clean water tank; the inlet of the proportional regulating valve is communicated with the outlet of the water pump, and the outlet of the proportional regulating valve is communicated with the spray head unit; the dust accumulation degree detection mechanism is used for scanning the reflectivity or light transmittance of different areas of the photovoltaic panel surface during walking; and the control system is electrically connected.

Description

Technical Field

[0001] This invention relates to an automatic photovoltaic panel cleaning device and a zoned intelligent cleaning control method, belonging to the field of photovoltaic panel cleaning technology. Background Technology

[0002] Chinese patent CN112737498B discloses an intelligent cleaning system for rooftop photovoltaic modules, including a rack and pinion track, a traveling gear, a sponge cleaning sleeve, water pipes, and a controller. The controller is electrically connected to a grid-connected inverter to read power generation data. The system calculates the cleaning benefit E by multiplying it by the electricity price J and subtracting the cleaning cost C to obtain the benefit B. Cleaning is initiated when B is greater than or equal to a set value B0, while excluding rainy, snowy, or dusty weather conditions to avoid misjudgment. This solution achieves automated cleaning, but it still relies solely on the overall power generation efficiency data provided by the inverter to determine the degree of dust accumulation. It cannot know the dust distribution in different areas of the photovoltaic panel surface, leading to cleaning decisions that can only be made for the entire module, either fully cleaned or not cleaned at all, failing to distinguish between areas with severe and mild dust accumulation, resulting in waste of water and electricity. Furthermore, the cleaning mechanism is a fixed-width integral structure, unable to adjust the cleaning range or intensity according to the actual dust distribution, and the cleaning effect and efficiency need further improvement. Summary of the Invention

[0003] To address the aforementioned problems in the existing technology, this invention provides an automatic photovoltaic panel cleaning device and a zoned intelligent cleaning control method, which achieves the effect of selectively choosing the cleaning area and cleaning intensity based on the actual dust accumulation and economic indicators.

[0004] The technical solution of the present invention is as follows: An automatic photovoltaic panel cleaning device includes a track mechanism comprising two parallel tracks arranged on both sides of the photovoltaic panel; a traveling trolley movably mounted on the tracks; a water spraying mechanism including a main beam, multiple nozzle units, and a lifting mechanism, the main beam being fixed to the traveling trolley and spanning the width of the photovoltaic panel; multiple nozzle units arranged at intervals along the length of the main beam, each nozzle unit being connected to the main beam via the lifting mechanism, and each nozzle unit integrating a pressure sensor and a flow sensor; a water supply mechanism including a cleaning liquid tank, a clean water tank, a water pump, a switching valve, and a proportional regulating valve, the inlet of the switching valve being connected to the outlet of the water pump, and the two outlets of the switching valve being connected to the cleaning liquid tank and the clean water tank, respectively; the inlet of the proportional regulating valve being connected to the outlet of the water pump, and the outlet of the proportional regulating valve being connected to the nozzle units; a dust accumulation detection mechanism for scanning the reflectivity or transmittance of different areas on the surface of the photovoltaic panel during travel; and an electrical connection to a control system.

[0005] The dust accumulation detection mechanism includes one or more optical sensors mounted on the traveling trolley; the control system includes a controller, which is communicatively connected to the photovoltaic inverter to obtain the overall power generation efficiency of the photovoltaic panel; the controller is also electrically connected to the optical sensors, the pressure sensor, the flow sensor, and the proportional control valve; the controller is used to control the movement of the lifting mechanism, the proportional control valve, and the traveling trolley based on the data from the optical sensors, the pressure sensor, the flow sensor, and the photovoltaic inverter.

[0006] The lifting mechanism is an electric push rod, the housing of which is fixed to the main beam, and the telescopic rod end of which is fixedly connected to the nozzle unit. The electric push rod has a built-in displacement sensor for feeding back the real-time height position of the nozzle unit to the controller.

[0007] The optical sensor is a linear CCD camera, and the scanning lines of the linear CCD camera are perpendicular to the traveling direction of the trolley, which is used to continuously acquire images of the photovoltaic panel surface when the trolley moves; the trolley is also equipped with a compressed air nozzle, which faces the lens of the linear CCD camera, and is used to remove dust from the lens surface during the scanning process.

[0008] The traveling trolley includes at least one drive wheel and at least one driven wheel. The drive wheel is driven by a stepper motor via a synchronous belt drive. The stepper motor is electrically connected to the controller. Each end of the traveling trolley is provided with a scraper blade, the lower edge of which contacts the upper surface of the track. The scraper blade is connected to the traveling trolley via an elastic hinge, allowing the scraper blade to flip upwards to avoid encountering a track joint.

[0009] The track has an I-shaped cross-section, the wheels of the trolley are grooved wheels, and the rims of the grooved wheels are engaged with the upper flanges of the I-shaped track. The lower flange of the track has multiple mounting holes for fixing to the photovoltaic panel bracket with bolts.

[0010] A method for intelligent zoned cleaning control of photovoltaic panels includes the following steps: S1: During the movement of the trolley along the track, the optical sensor scans the surface of the photovoltaic panel to obtain reflectivity or transmittance data of different areas of the photovoltaic panel surface, and divides the photovoltaic panel surface into several partitions, each partition corresponding to one or more nozzle units; S2: Calculate the dust accumulation score for each zone based on the reflectance or transmittance data of each zone. ;in, For partition numbering, The standard reflectance of the photovoltaic panel surface under clean conditions. For the first Average reflectance measured in each zone; A higher value indicates more severe dust accumulation; S3: Obtain the overall power generation efficiency of the photovoltaic panels fed back by the photovoltaic inverter. And combined with the dust accumulation score of each zone Estimate the expected increase in power generation efficiency that each zone can recover after cleaning. ,in, This represents the highest historical power generation efficiency for this zone under clean conditions. For the first The irradiance weighting coefficient of each partition is calculated based on the location of the partition in the photovoltaic array and the solar altitude angle and azimuth angle on that day; S4: Get the current electricity price Water price And the energy consumption cost per unit time for a single cleaning. Calculate the cleaning cost for each partition. ,in, This represents the water consumption per unit time for the sprinkler unit corresponding to this zone. This represents the power consumption per unit time of the nozzle unit and lifting mechanism corresponding to this zone. The cost of equipment depreciation is allocated per unit of time. This is the expected cleaning time for this partition; S5: Calculate the cleaning efficiency of each partition. ,in This refers to the rated power of the photovoltaic panels corresponding to this zone; S6: For each partition, determine... Is it greater than or equal to the preset benefit threshold? If so, mark the partition as the partition to be cleaned; S7: Based on the location distribution of all zones to be cleaned, generate cleaning paths and nozzle unit operating parameters, including: controlling the nozzle unit corresponding to the zone to be cleaned to descend to a preset height via the lifting mechanism; controlling the proportional regulating valve to increase the outlet water pressure and flow rate of the nozzle unit; and controlling the nozzle units corresponding to zones not to be cleaned to remain at a high position or be turned off. S8: Control the traveling trolley to move along the track, and simultaneously perform cleaning operations according to the generated working parameters; S9: After cleaning, the photovoltaic panel surface is scanned again using the optical sensor to obtain the reflectivity or transmittance data after cleaning, the actual cleaning effect of each zone is calculated, and this data is stored in the historical database for updating the subsequent step S3. The estimation model.

[0011] Among them, the irradiation weighting coefficient in step S3 The calculation method includes the following sub-steps: S3.1: Calculate the solar altitude angle according to the current date and time using the following formula. and solar azimuth : , ,in, The solar declination angle, This refers to the latitude of the location where the photovoltaic panels will be installed. Solar hour angle; S3.2: Based on the solar altitude angle Sun azimuth Given the orientation and tilt angle of the photovoltaic panels, calculate the angle of incidence of sunlight on the plane containing the i-th partition. ; S3.3: Calculate the theoretical irradiance of the i-th partition using the following formula. ,in, Normal direct irradiance; S3.4: Calculate the irradiation weighting coefficient according to the following formula. , where n is the total number of partitions.

[0012] Among them, the preset benefit threshold mentioned in step S6 This is a dynamic threshold, whose value is determined based on the current electricity price J and the probability of precipitation in the 24-hour weather forecast. Calculate using the following formula: ,in, Basic benefit threshold, This is the risk adjustment factor.

[0013] The present invention has the following beneficial effects: This invention utilizes optical sensors mounted on a mobile trolley to scan the surface of photovoltaic panels and acquire dust distribution data. This is combined with nozzle units spaced along the main beam, each with its own independent lifting mechanism, and a closed-loop control circuit comprised of pressure sensors, flow sensors, and proportional control valves integrated within each nozzle unit. Furthermore, a controller calculates the cleaning efficiency of each zone and compares it with dynamic thresholds. This achieves a complete, refined cleaning process, from dust detection and zoning decisions to differentiated execution. It enables targeted selection of cleaning areas and intensities based on actual dust accumulation and economic indicators, reducing unnecessary water and electricity consumption while ensuring power generation efficiency recovery.

[0014] This invention reduces residual moisture and watermarks by installing a squeegee and an air knife on a traveling trolley, and then scraping and drying the surface of the cleaned photovoltaic panel behind the nozzle unit. This reduces the impact of watermarks on power generation efficiency.

[0015] This invention achieves stable guidance of the trolley on the track and automatic cleaning of the track surface by using an I-shaped track combined with grooved wheels and installing scraper blades with elastic hinges at both ends of the trolley. This reduces the risk of the trolley getting stuck and derailing. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention. The reference numerals in the figure are as follows: 1. Photovoltaic panel; 2. Track; 3. Traveling trolley; 4. Main beam; 5. Nozzle unit; 6. Electric push rod; 7. Cleaning fluid tank; 8. Clean water tank; 9. Water pump; 10. Optical sensor; 12. Compressed air blow nozzle; 31. Drive wheel; 32. Driven wheel; 34. Scraper; 35. Flexible hinge; 36. Squeegee. Detailed Implementation

[0017] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0018] Please see Figure 1 The invention provides a technical solution: Example 1: The automatic photovoltaic panel cleaning device in this embodiment mainly includes a track mechanism, a traveling trolley 3, a water spraying mechanism, a water supply mechanism, a dust accumulation detection mechanism, and a control system.

[0019] The track mechanism consists of two parallel tracks 2, which are installed on both sides of the photovoltaic panel 1. The cross-section of the track 2 is I-shaped. The wheels of the traveling trolley 3 are grooved wheels, and the rims of the grooved wheels are engaged with the upper flanges of the I-shaped track 2. This kind of cooperation can effectively prevent the traveling trolley 3 from lateral deviation or derailment during travel.

[0020] The lower flange of track 2 has multiple mounting holes, which are fixedly connected to the photovoltaic panel bracket by bolts. During installation, the length and position of track 2 can be adjusted according to the actual site conditions.

[0021] The traveling trolley 3 is mounted on the track 2 and can move back and forth along the track 2. The chassis of the traveling trolley 3 is equipped with a drive wheel 31 and at least one driven wheel 32. The drive wheel 31 is driven by a stepper motor through a synchronous belt drive. The stepper motor is a waterproof motor with an IP65 protection rating to adapt to the outdoor humid and dusty working environment. The motor housing is equipped with heat dissipation fins, which can dissipate heat naturally during long-term continuous operation without the need for an additional fan.

[0022] The stepper motor is electrically connected to the controller, which controls the stepper motor's speed and angle by sending pulse signals, thereby achieving precise positioning and uniform speed movement of the traveling trolley 3. A scraper 34 is located at each of the front and rear ends of the traveling trolley 3. The lower edge of the scraper 34 contacts the upper surface of the track 2, used to scrape away dust and debris accumulated on the track surface during movement, preventing these debris from affecting the wheels' grip and the stability of the movement. The scraper 34 is connected to the traveling trolley 3 via an elastic hinge 35. When the scraper 34 encounters a protrusion or gap at the joint of the track 2, the elastic hinge 35 allows the scraper 34 to rotate upwards at a certain angle to avoid the obstacle. After passing the obstacle, the scraper 34 automatically returns to its original position under the action of the elastic hinge 35, continuing to maintain contact with the upper surface of the track 2.

[0023] The water spraying mechanism is installed on the traveling trolley 3 and mainly includes a main beam 4, multiple nozzle units 5 and corresponding lifting mechanisms.

[0024] The main beam 4 is fixed on the traveling trolley 3 and spans the width of the photovoltaic panel 1. Its length is slightly greater than the width of the photovoltaic panel 1 to ensure that the nozzle unit 5 can cover the entire light-receiving surface of the photovoltaic panel 1.

[0025] Multiple nozzle units 5 are arranged at equal intervals along the length of the main beam 4, and each nozzle unit 5 is connected to the main beam 4 through an independent lifting mechanism.

[0026] In this embodiment, the lifting mechanism adopts an electric push rod 6. The housing of the electric push rod 6 is fixed on the main beam 4, and the end of its telescopic rod is fixedly connected to the nozzle unit 5. The electric push rod 6 has a built-in displacement sensor, which can provide real-time feedback to the controller on the current height position of the nozzle unit 5, thereby realizing precise adjustment of the distance between the nozzle unit 5 and the surface of the photovoltaic panel 1.

[0027] The nozzle unit 5 itself can use a common fan-shaped atomizing nozzle or a high-pressure columnar nozzle, and the specific type can be selected and replaced according to the actual cleaning needs and the on-site water quality. Each nozzle unit 5 integrates a pressure sensor and a flow sensor, which are used to monitor the water pressure and flow rate of the nozzle unit 5 in real time and feed the data back to the controller so that the controller can dynamically adjust the water parameters according to the actual working conditions.

[0028] The water supply system includes a cleaning fluid tank 7, a clean water tank 8, a water pump 9, a switching valve, and a proportional regulating valve. Both the cleaning fluid tank 7 and the clean water tank 8 are fixedly mounted on the traveling trolley 3 and move with it, avoiding the tangling and wear problems caused by dragging long-distance hoses, and also simplifying the pipeline layout. The water pump 9 is also mounted on the traveling trolley 3, and its inlet can be selectively connected to either the cleaning fluid tank 7 or the clean water tank 8 via the switching valve. The switching valve is a two-position three-way solenoid valve, and its on / off state is controlled by the controller. The inlet of the proportional regulating valve is connected to the outlet of the water pump 9, and the outlet of the proportional regulating valve is connected to each nozzle unit 5. The proportional regulating valve is used to adjust its valve core opening according to the signal output by the controller, thereby changing the water pressure and flow rate flowing to the nozzle unit 5.

[0029] By combining the switching valve and the proportional regulating valve, the water supply mechanism can achieve a two-stage cleaning process: first, spraying cleaning solution to soak and soften the dirt, and then switching to high-pressure rinsing with clean water. In each stage, the water pressure and flow rate can be adjusted differently according to the degree of ash accumulation in different areas.

[0030] The dust accumulation detection mechanism is used to scan the reflectivity or transmittance of different areas on the surface of the photovoltaic panel 1 during the walking process, so as to determine the severity of dust accumulation in each area.

[0031] In this embodiment, the dust accumulation detection mechanism includes one or more optical sensors 10 mounted on the traveling trolley 3. The optical sensors 10 can be photoelectric sensors or spectral sensors, and their detection signals are transmitted to the controller for processing and analysis. The control system includes a controller that is communicatively connected to the photovoltaic inverter to acquire the overall power generation efficiency data of the photovoltaic panel 1. The controller is also electrically connected to the optical sensors 10, pressure sensors, flow sensors, and proportional control valves, respectively, to comprehensively determine the dust accumulation level and cleaning requirements of each zone based on the data collected by these sensors and the power generation efficiency data fed back by the photovoltaic inverter, and accordingly control the lifting mechanism, proportional control valve, and the movement of the traveling trolley 3. The entire device is powered by a battery mounted on the traveling trolley 3, with its charging input terminal connected to the DC output terminal of the photovoltaic panel 1. The battery is charged using the power generated by the photovoltaic panel 1, achieving energy self-sufficiency without the need for an external power source.

[0032] Specifically, the optical sensor 10 is a linear CCD camera. The scanning lines of the linear CCD camera are perpendicular to the direction of travel of the trolley 3, and are used to continuously acquire images of the surface of the photovoltaic panel 1 when the trolley 3 moves. The trolley 3 is also equipped with a compressed air nozzle 12, which faces the lens of the linear CCD camera and is used to remove dust from the lens surface during the scanning process.

[0033] A method for intelligent zoned cleaning control of photovoltaic panels includes the following steps: S1: As the trolley 3 moves along the track 2, the surface of the photovoltaic panel 1 is scanned by the optical sensor 10 mounted on the trolley 3 to obtain reflectivity or transmittance data of different areas on the surface of the photovoltaic panel 1. The scanning line of the optical sensor 10 is perpendicular to the traveling direction of the trolley 3, enabling continuous acquisition of image information of the surface of the photovoltaic panel 1 while the trolley 3 moves at a constant speed. After the acquired image data is transmitted to the controller, the controller divides the surface of the photovoltaic panel 1 into several grid-like partitions along the length and width directions, with each partition corresponding to one or more nozzle units 5.

[0034] The purpose of dividing the data into zones is to refine the dust accumulation status of the entire photovoltaic panel 1 to a local scale, so as to avoid masking the problem of severe dust accumulation in some areas due to the averaging of the overall data. S2: Calculate the dust accumulation score for each zone based on the reflectance or transmittance data of each zone. ;in, For partition numbering, This is the standard reflectance of photovoltaic panel 1 under clean surface conditions. This value can be obtained by calibrating the clean photovoltaic panel during the initial installation and commissioning of the device. For the first Average reflectance measured in each zone; A higher value indicates more severe dust accumulation; when A reflectance close to 0% indicates that the area is basically clean, while a reflectance close to 100% indicates that the area is completely covered by dust. The reason for using reflectance difference normalization to calculate the dust accumulation score is that the change in reflectance can directly reflect the degree of shading on the surface of photovoltaic panel 1, and there is a good linear correlation between reflectance and the decrease in power generation efficiency. This law has been verified in a large number of documents and engineering practices.

[0035] S3: The controller obtains the overall power generation efficiency of photovoltaic panel 1 from the photovoltaic inverter via the communication interface. And combined with the dust accumulation score of each zone Estimate the expected increase in power generation efficiency that each zone can recover after cleaning. ,in, This is the highest historical power generation efficiency of the zone under clean conditions. This value can be extracted from historical operating data, and is usually selected as the peak power generation efficiency of the zone within one week after the most recent cleaning. For the first The irradiance weighting coefficient of each partition is calculated based on the location of the partition in the photovoltaic array and the solar altitude angle and azimuth angle on that day; The reason for introducing the irradiance weighting coefficient is that the light intensity received by different areas of the photovoltaic panel 1 at the same time is not the same. For example, areas near the edge may be shaded by adjacent modules during the morning and evening due to the lower solar altitude angle, while the irradiance conditions in the central area are usually better than those in the edge areas. If this difference is not considered and a uniform weight is used directly to estimate the cleaning benefit, the cleaning value of the edge areas will be overestimated, leading to decision bias. The specific calculation method of the irradiance weighting coefficient will be detailed below.

[0036] S4: While completing the revenue estimation, the controller also needs to calculate the cleaning cost for each zone. Obtain the current electricity price. Water price And the energy consumption cost per unit time for a single cleaning. Calculate the cleaning cost for each partition. ,in, The unit time water consumption of the sprinkler unit (5) corresponding to the zone is determined by the opening degree of the proportional control valve and the model of the sprinkler unit 5. The power consumption per unit time of the nozzle unit 5 and lifting mechanism corresponding to this zone is calculated from the rated power of the stepper motor and electric push rod 6. The depreciation cost per unit time is calculated from the total investment and design service life of the equipment. The expected cleaning time for this zone is determined by the area of ​​the zone and the coverage width of the sprinkler unit 5; water price Information can be obtained from the tiered water pricing published by the local water authority; electricity prices... Considering that peak-valley time-of-use pricing is commonly implemented for industrial and commercial electricity consumption, the controller can determine the current time period based on the real-time clock and call up the corresponding electricity price value; The cleaning cost is broken down into three components: water consumption, electricity consumption, and equipment depreciation. The cost of each zone varies depending on the operating parameters of its nozzle unit 5. The purpose of this is to make the cost accounting as close as possible to the actual situation and avoid the error caused by using fixed costs to replace dynamic costs.

[0037] S5: Calculate the cleaning efficiency of each partition. ,in This refers to the rated power of photovoltaic panel 1 corresponding to this partition; This refers to the net benefit gained from cleaning the area, which is the electricity revenue generated from increased power generation after cleaning, minus the water and electricity costs and equipment depreciation incurred during the cleaning process. If A positive value indicates that cleaning that partition is economically worthwhile; if... A negative value indicates that the cost of cleaning the partition exceeds the benefits, and cleaning should be postponed or abandoned in this case.

[0038] S6: For each partition, determine... Is it greater than or equal to the preset benefit threshold? If so, mark the partition as the partition to be cleaned; It will not be cleaned in this cleaning operation. The benefit threshold B0 mentioned here is not a fixed constant, but a dynamically adjusted value.

[0039] The calculation formula is: ,in The basic benefit threshold is equal to the average total cost of a single cleaning divided by the number of zones, and can be obtained through statistical analysis of trial operation data during the initial stage of equipment commissioning. This represents the probability of precipitation in the weather forecast for the next 24 hours, with a value ranging from 0 to 1. The risk adjustment coefficient is initially set to 1.0 and will be dynamically adjusted based on the accuracy of weather forecasts over the past 30 days. The purpose of introducing precipitation probability is to avoid cleaning just before rain. Rainwater has a cleaning effect, but cleaning the solar panels before rainfall would quickly bring dust back onto the panels, diluting the cleaning effect and wasting resources. By incorporating precipitation probability into the threshold calculation, the benefit threshold automatically increases when the forecast indicates a high probability of rain within the next 24 hours, making the system more inclined to postpone cleaning and thus avoiding unnecessary expenditures.

[0040] S7: After determining the location of all zones to be cleaned, the controller generates the cleaning path and nozzle unit operating parameters based on the distribution of these zones. Specifically, for each zone to be cleaned, the controller controls the corresponding nozzle unit 5 to descend to a preset height via the electric push rod 6, bringing the nozzle closer to the photovoltaic panel surface to increase the rinsing pressure. At the same time, the controller controls the proportional regulating valve to increase the outlet water pressure and flow rate of the nozzle unit 5. For zones not to be cleaned, the controller controls its corresponding nozzle unit 5 to remain at a high position or directly closes the inlet solenoid valve of the nozzle unit, preventing it from participating in this cleaning process. S8: The controller controls the traveling trolley 3 to move along the track 2 at a set speed, and at the same time performs the cleaning operation according to the working parameters generated above. The moving speed of the traveling trolley 3 is coordinated with the water pressure and flow rate of the nozzle unit 5 to ensure that each area to be cleaned can get enough rinsing time. S9: After cleaning, the controller controls the trolley 3 to move along track 2 again, while simultaneously re-scanning the surface of the photovoltaic panel 1 using optical sensor 10 to obtain reflectivity or transmittance data after cleaning. This data is then compared with the data before cleaning to calculate the actual cleaning effect for each zone. The actual cleaning effect can be represented by the change in dust accumulation score before and after cleaning, or by the actual increase in power generation efficiency after cleaning. This data is stored in the controller's historical database for subsequent analysis of step S3. The estimation model is updated. As the number of cleaning cycles increases and historical data accumulates in the database, the estimation model becomes more accurate, leading to more rational system decisions.

[0041] Irradiation weighting coefficient in step S3 The calculation method includes the following sub-steps: S3.1: Calculate the solar altitude angle according to the current date and time using the following formula. and solar azimuth The solar altitude angle is the angle between the sun's rays and the horizon, while the solar azimuth angle is the angle between the projection of the sun's rays onto the horizon and the due south direction. , ,in, It is the solar declination angle (which can be looked up in a table based on the date or calculated using an approximate formula). This refers to the latitude of the location where the photovoltaic panels will be installed. It is the solar hour angle (calculated from the time difference between the current time and noon); S3.2: Based on the solar altitude angle Sun azimuth Given the orientation and tilt angle of photovoltaic panel 1, calculate the angle of incidence of sunlight with the plane containing the i-th partition. The incident angle is the angle between the sunlight and the normal to the surface of the photovoltaic panel 1. When the sunlight is perpendicular to the surface of the photovoltaic panel 1, the incident angle is 0°. At this time, the irradiance received by the photovoltaic panel is the maximum. The calculation of the incident angle requires the use of coordinate transformation methods in vector geometry. Specifically, the solar direction vector is transformed into the local coordinate system of the photovoltaic panel surface, and then the angle between the vector and the surface normal vector is calculated. S3.3: Calculate the theoretical irradiance of the i-th partition using the following formula. ,in, This is the normal direct irradiance, which is the irradiance when the sun's rays are perpendicular to the ground. This value can be measured in real time by the local weather station or irradiance sensor. It reflects the degree of attenuation of irradiance when sunlight is incident at an angle. =0° =1, = ;when =90° =0, =0.

[0042] S3.4: Calculate the irradiation weighting coefficient according to the following formula. Where n is the total number of partitions; where the denominator is the sum of the theoretical irradiance of all partitions, and after normalization, the sum of the irradiance weight coefficients of all partitions is 1; used to calculate the ... The proportion of the theoretical irradiance received by each partition at the current moment to the total theoretical irradiance of the entire photovoltaic panel is given. The stronger the irradiance of the partition, the greater its weight, and the more power generation can be restored after cleaning.

[0043] It should be noted that the above calculation of the irradiance weighting coefficient only considers direct irradiance and does not take into account the effects of diffuse and reflected irradiance. In practical applications, if the air quality at the photovoltaic panel installation site is poor or there is a lot of cloud cover, the proportion of diffuse irradiance to total irradiance will increase significantly. In this case, using only direct irradiance to calculate the weighting coefficient will produce a certain error. For this situation, the formula for calculating theoretical irradiance can be adjusted in step S3.3 to... ,in, This is the diffuse irradiance component, the value of which can be estimated from local meteorological data or empirical models. This adjustment can be flexibly selected according to the needs of the actual application scenario, and will not be elaborated here.

[0044] Example 2: This second embodiment differs only in steps S5 and S6 of the first embodiment; the remaining apparatus and steps are the same as in the first embodiment. Specifically: S5: Calculate the cleaning efficiency of each partition. ,in The rated power of photovoltaic panel 1 corresponding to this partition; for each partition, determine... Is it greater than or equal to the preset benefit threshold? If so, mark the partition as the initial partition to be cleaned. Then, based on the impact of the dirty water generated during the initial cleaning of all the downstream zones on the downstream zones, the ash accumulation score of each downstream zone contaminated by the dirty water is corrected to obtain the corrected ash accumulation score. and based on Recalculate the expected increase in power generation efficiency for this region. and cleaning benefits Meanwhile, for each initial cleaning zone... Based on the degree of pollution it causes to each downstream zone, calculate the total loss caused by its pollution to each downstream zone. and from its initial benefits After deducting from the middle, the cleaning benefit after correction for the upstream partition is obtained. ; In step S5, the ash accumulation score of each downstream zone contaminated by the dirty water generated during the initial cleaning of all the zones to be cleaned is corrected based on the pollution impact on the downstream zones, and the total loss from upstream zone contamination to downstream zones is calculated. Specifically, it includes the following sub-steps: S5.1: Obtain the tilt angle of the photovoltaic panel Surface roughness coefficient and the center-to-center spacing of each zone along the inclined direction For each initial section to be cleaned Based on the water impact velocity of its nozzle unit The tilt angle of the photovoltaic panel Surface roughness coefficient Calculate the maximum flow distance of the dirty water generated during cleaning along the inclined direction on the surface of photovoltaic panel 1. ,in It is the acceleration due to gravity; S5.2: For each partition Identify all partitions located upstream of this partition that have been marked as initially to be cleaned. If partition The center and the initial cleaning zone The distance from the center along the inclined direction Then determine the partition. It will be affected by the initial cleaning of the partition. The impact of dirty water generated during cleaning, and the calculation of zones according to the following rules. Due to the initial cleaning of the partition The resulting change in ash accumulation score ; like Then partition Defined as a flushing transition zone, this area is primarily in a flowing state, where pollutants are less likely to settle. ,in The scouring coefficient; like Then partition Defined as a sedimentation zone, this area allows pollutants to settle and decompose in polluted water. ,in The deposition coefficient; in, It is the flow attenuation coefficient, and its function is to classify the behavior pattern of dirty water as it flows through different areas; The value is usually between 0.6 and 0.8. The specific value needs to be determined through experiments or on-site data, and is related to factors such as the surface material of the photovoltaic panel, tilt angle, and viscosity of dirty water.

[0045] S5.3: For each partition The changes in ash accumulation scores caused by all upstream preliminary cleaning zones are summed to obtain the overall ash accumulation score change. Calculate the corrected ash accumulation score Then Substitute the values ​​and calculate to obtain the corrected expected power generation efficiency increment. And calculate the corrected cleaning benefits. ; S5.4: For each initial cleaning zone Calculate the total losses caused by pollution in each downstream zone. ,in For the upstream preliminary cleaning zone The set of downstream zones contaminated with dirty water, where T is the time interval between the current cleaning and the next planned cleaning; and the initial benefits from the upstream zone. After deducting from the middle, the cleaning benefit after correction for the upstream partition is obtained. .

[0046] S6: For each partition, if the partition is the initial partition to be cleaned. Then the corrected cleaning efficiency will be used. Compared with the preset benefit threshold If a comparison is made, If the zone is contaminated, then mark it as the final zone to be cleaned; if the zone is a downstream zone contaminated by dirty water, then use the corrected cleaning efficiency. Compared with the preset benefit threshold If a comparison is made, If a zone is found to be contaminated with dirty water, it will be marked as the final zone to be cleaned; other zones that are not contaminated with dirty water and whose initial benefits do not meet the standards will not be marked as the final zones to be cleaned.

[0047] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. An automatic cleaning device for photovoltaic panels, characterized in that, include: The track mechanism includes two parallel tracks (2) set on both sides of the photovoltaic panel (1); a trolley (3) movably mounted on the tracks (2); and a water spraying mechanism including a main beam (4), multiple nozzle units (5), and a lifting mechanism. The main beam (4) is fixed on the trolley (3) and spans the width of the photovoltaic panel (1). Multiple nozzle units (5) are arranged at intervals along the length of the main beam (4). Each nozzle unit (5) is connected to the main beam (4) through the lifting mechanism. Each nozzle unit (5) integrates a pressure sensor and a flow meter. A quantity sensor; a water supply mechanism, including a cleaning fluid tank (7), a clean water tank (8), a water pump (9), a switching valve, and a proportional regulating valve, wherein the inlet of the switching valve is connected to the outlet of the water pump (9), and the two outlets of the switching valve are connected to the cleaning fluid tank (7) and the clean water tank (8) respectively; the inlet of the proportional regulating valve is connected to the outlet of the water pump (9), and the outlet of the proportional regulating valve is connected to the nozzle unit (5); a dust accumulation detection mechanism, used to scan the reflectivity or transmittance of different areas on the surface of the photovoltaic panel (1) during walking; and electrically connected to the control system.

2. The automatic photovoltaic panel cleaning device as described in claim 1, characterized in that: The dust accumulation detection mechanism includes one or more optical sensors (10) installed on the traveling trolley (3); the control system includes a controller, which is communicatively connected to the photovoltaic inverter and is used to obtain the overall power generation efficiency of the photovoltaic panel (1); the controller is also electrically connected to the optical sensor (10), the pressure sensor, the flow sensor and the proportional regulating valve; the controller is used to control the operation of the lifting mechanism, the proportional regulating valve and the traveling trolley (3) according to the data of the optical sensor (10), the pressure sensor, the flow sensor and the photovoltaic inverter.

3. The automatic photovoltaic panel cleaning device as described in claim 2, characterized in that: The lifting mechanism is an electric push rod (6), the housing of which is fixed to the main beam (4), and the end of the telescopic rod of which is fixedly connected to the nozzle unit (5); the electric push rod (6) has a built-in displacement sensor for feeding back the real-time height position of the nozzle unit to the controller.

4. The automatic photovoltaic panel cleaning device as described in claim 2, characterized in that: The optical sensor (10) is a linear CCD camera. The scanning lines of the linear CCD camera are perpendicular to the traveling direction of the trolley (3) and are used to continuously acquire images of the surface of the photovoltaic panel (1) when the trolley (3) moves. The trolley (3) is also equipped with a compressed air nozzle (12) which faces the lens of the linear CCD camera and is used to remove dust from the lens surface during the scanning process.

5. The automatic photovoltaic panel cleaning device as described in claim 1, characterized in that: The trolley (3) includes at least one drive wheel (31) and at least one driven wheel (32). The drive wheel (31) is driven by a stepper motor through a synchronous belt drive. The stepper motor is electrically connected to the controller. Each end of the trolley (3) is provided with a scraper (34). The lower edge of the scraper (34) contacts the upper surface of the track (2). The scraper (34) is connected to the trolley (3) through an elastic hinge (35), so that the scraper (34) can flip upward to avoid the joint of the track (2).

6. The automatic photovoltaic panel cleaning device as described in claim 1, characterized in that: The track (2) has an I-shaped cross section, and the wheels of the traveling trolley (3) are grooved wheels. The rims of the grooved wheels are engaged with the upper flanges of the I-shaped track (2). The lower flange of the track (2) is provided with multiple mounting holes for fixing to the photovoltaic panel bracket with bolts.

7. The automatic photovoltaic panel cleaning device as described in claim 1, characterized in that: The trolley (3) is also equipped with a wiper (36) and an air knife. The wiper (36) and the air knife are both located behind the nozzle unit (5). The wiper (36) is made of rubber and its lower edge is in elastic contact with the surface of the photovoltaic panel (1) to remove the residual water film on the surface of the photovoltaic panel (1). The air outlet of the air knife faces the surface of the photovoltaic panel (1) to blow dry the water droplets remaining after wiping. The air knife is connected to a compressed air source, and the compressed air source is electrically connected to the controller.

8. A method for intelligent zoned cleaning control of photovoltaic panels, applied to the automatic cleaning device for photovoltaic panels according to any one of claims 1-7, characterized in that, Includes the following steps: S1: During the movement of the trolley (3) along the track (2), the optical sensor (10) scans the surface of the photovoltaic panel (1) to obtain the reflectivity or transmittance data of different areas of the photovoltaic panel (1) surface, and divides the surface of the photovoltaic panel (1) into several partitions, each partition corresponding to one or more nozzle units (5). S2: Calculate the dust accumulation score for each zone based on the reflectance or transmittance data of each zone; the dust accumulation score indicates the current severity of dust accumulation in that zone, and the higher the dust accumulation score, the more severe the dust accumulation. S3: Obtain the overall power generation efficiency of the photovoltaic panel (1) fed back by the photovoltaic inverter, and estimate the expected power generation efficiency increment that can be recovered by each partition after cleaning, in combination with the dust accumulation score of each partition. The expected power generation efficiency increment is related to the dust accumulation score of the partition, the highest historical power generation efficiency of the partition in the clean state, and the irradiation weight coefficient of the partition. S4: Obtain the current electricity price, water price, and energy consumption cost per unit time for a single cleaning, and calculate the cleaning cost for each zone. The cleaning cost is related to the water consumption per unit time, power consumption per unit time, equipment depreciation amortization cost, and expected cleaning time of the corresponding nozzle unit for that zone. S5: Calculate the initial cleaning benefit for each zone, where the initial cleaning benefit is the expected increase in power generation efficiency that can be recovered after cleaning the zone multiplied by the rated power of the photovoltaic panel corresponding to the zone, multiplied by the current electricity price, and then minus the cleaning cost of the zone. Compare the initial cleaning benefit of each zone with a preset benefit threshold. If the initial cleaning benefit is greater than or equal to the benefit threshold, mark the zone as a preliminary zone to be cleaned. Then, based on the pollution impact of the dirty water generated during the cleaning of all preliminary zones to be cleaned on downstream zones along the tilt direction of the photovoltaic panel surface, correct the ash accumulation score of each downstream zone polluted by dirty water to obtain a corrected ash accumulation score. Based on the corrected ash accumulation score, recalculate the expected increase in power generation efficiency and the cleaning benefit of the downstream zone. At the same time, for each preliminary zone to be cleaned, calculate the total loss caused by its pollution to downstream zones based on the degree of pollution it causes to each downstream zone, and deduct it from its initial benefit to obtain the corrected cleaning benefit of the upstream zone. S6: For each partition, if the partition is a preliminary partition to be cleaned, the corrected cleaning benefit is compared with the benefit threshold. If the corrected cleaning benefit is greater than or equal to the benefit threshold, the partition is marked as the final partition to be cleaned. If the zone is a downstream zone contaminated by dirty water, the corrected cleaning benefit is compared with the benefit threshold. If the corrected cleaning benefit is greater than or equal to the benefit threshold, the zone is marked as the final zone to be cleaned. The remaining partitions will not be included in the final partitions to be cleaned; S7: Based on the location distribution of all the areas to be cleaned, generate the cleaning path and nozzle unit working parameters, including: controlling the nozzle unit (5) corresponding to the area to be cleaned to descend to the preset height through the lifting mechanism, controlling the proportional regulating valve to increase the outlet water pressure and flow rate of the nozzle unit (5); controlling the nozzle unit (5) corresponding to the non-area to be cleaned to remain at a high position or be closed; S8: Control the walking trolley (3) to move along the track (2) and perform cleaning operations according to the generated working parameters; S9: After cleaning, the surface of the photovoltaic panel (1) is scanned again by the optical sensor (10) to obtain the reflectivity or transmittance data after cleaning, calculate the actual cleaning effect of each zone, and store the data in the historical database to update the estimation model of the expected increase in power generation efficiency.

9. The photovoltaic panel zoned intelligent cleaning control method as described in claim 8, characterized in that, Irradiation weighting coefficient in step S3 The calculation method includes the following sub-steps: S3.1: Calculate the solar altitude angle and solar azimuth angle based on the current date and time; S3.2: Based on the solar altitude angle, solar azimuth angle, and the orientation and tilt angle of the photovoltaic panel (1), calculate the relationship between the sunlight and the first solar radiation. The angle of incidence on the plane containing each partition; S3.3: Calculate the first... based on the incident angle. Theoretical irradiance of each zone; S3.4: The first The irradiance weighting coefficient is obtained by dividing the theoretical irradiance of each partition by the sum of the theoretical irradiances of all partitions.

10. The photovoltaic panel zoned intelligent cleaning control method as described in claim 8, characterized in that, Step S5, which involves correcting the ash accumulation score of each downstream zone contaminated by the contaminated water based on the impact of the dirty water generated during the initial cleaning of all the downstream zones, and calculating the total loss of upstream zone contamination downstream, specifically includes the following sub-steps: S5.1: Obtain the tilt angle, surface roughness coefficient, and center-to-center distance of each partition along the tilt direction of the photovoltaic panel. For each partition to be initially cleaned, calculate the maximum flow distance of the dirty water generated during cleaning along the tilt direction on the surface of the photovoltaic panel based on the water impact velocity of its nozzle unit and the tilt angle and surface roughness coefficient of the photovoltaic panel. S5.2: For each zone, identify all zones upstream of that zone that have been marked as initially to be cleaned. If the distance between the center of that zone and the center of the upstream initially to be cleaned zone along the inclined direction is less than or equal to the maximum flow distance, then it is determined that the zone will be affected by the dirty water generated by the cleaning of the upstream initially to be cleaned zone, and the change in ash accumulation score of that zone due to the upstream initially to be cleaned zone is calculated according to the following rules: If the distance is less than the maximum flow distance multiplied by a preset flow attenuation coefficient, the zone is defined as a flushing transition zone. In this zone, dirty water is mainly in a flowing state, and pollutants are not easy to deposit. The change in its ash accumulation score is negative, indicating that the ash accumulation score is slightly reduced. If the distance is greater than or equal to the maximum flow distance multiplied by the flow attenuation coefficient, the zone is defined as a sedimentation accumulation zone. In this zone, the flow rate of dirty water slows down and pollutants settle. The change in its ash accumulation score is positive and proportional to the difference between the ash accumulation score of the upstream zone to be cleaned and the ash accumulation score of the zone itself, indicating a significant increase in the ash accumulation score. S5.3: For each zone, sum up the changes in ash accumulation scores caused by all upstream zones to be initially cleaned to obtain a comprehensive change in ash accumulation score. Add the comprehensive change in ash accumulation score to the original ash accumulation score of the zone to obtain a corrected ash accumulation score. Then replace the original ash accumulation score with the corrected ash accumulation score and recalculate the expected power generation efficiency increment and cleaning benefits of the zone. S5.4: For each initial cleaning zone, record the set of downstream zones affected by its dirty water, calculate the total loss caused by the pollution of each downstream zone, the total loss being the sum of the power generation loss corresponding to the change in ash accumulation score caused by the upstream zone in each downstream zone; and subtract it from the initial benefit of the upstream zone to obtain the corrected cleaning benefit of the upstream zone.

Images