A gas-liquid compatible photovoltaic cleaning and thermal management synergic system and a control method thereof

Abstract

The application discloses a kind of gas-liquid compatible photovoltaic cleaning and heat management collaborative system and its control method, belong to photovoltaic system technical field.The system includes fluid oscillator, gas supply unit, water supply unit, medium selection unit, heat management unit and control unit.The medium selection unit only allows gas or liquid single medium to enter the same fluid oscillator at the same time, realizes dry-wet alternate cleaning;The heat management unit adopts vertical layered two-phase change material structure, realizes long-acting temperature control and transient cooling cooperation.The control method matches daily cleaning, heavy pollution cleaning, transient strong cooling, low-temperature cleaning and other modes according to real-time parameters, and is closed-loop optimized.The application solves the problems of large water consumption of traditional photovoltaic cleaning, winter operation, insufficient transient response of heat management, realizes all-weather all-scene unattended operation and maintenance, significantly improves power generation efficiency and reduces operation and maintenance cost.

Description

Technical Field

[0001] This invention belongs to the field of photovoltaic system technology, specifically relating to a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system and its control method, which is applicable to the intelligent operation and maintenance and power generation efficiency improvement of various centralized and distributed photovoltaic power plants. Background Technology

[0002] With the advancement of my country's "dual-carbon" goals and the construction of a new energy system, the installed capacity of photovoltaic power generation has continued to grow rapidly, becoming a core component of my country's clean energy system. However, outdoor photovoltaic modules consistently face two major challenges that restrict power generation efficiency and service safety during long-term operation: First, the problem of dust accumulation on the surface of photovoltaic modules. Photovoltaic modules operating outdoors for extended periods are prone to accumulating pollutants such as atmospheric dust, bird droppings, and fallen leaves, directly reducing the light transmittance of the glass and causing a significant decrease in the output power of the photovoltaic modules. At the same time, uneven dust accumulation can lead to series mismatch, forming localized hot spot effects, which can accelerate module aging or even burn out cells and cause safety accidents. Second, the problem of controlling the operating temperature of photovoltaic modules. The photoelectric conversion efficiency of photovoltaic cells decreases significantly with increasing temperature. Under strong sunlight at midday outdoors, the surface temperature of the modules can easily exceed the high-efficiency operating range, causing a sharp drop in power generation efficiency. Furthermore, long-term operation at high temperatures will significantly shorten the lifespan of the modules.

[0003] Current technical solutions in the industry to address the above problems all have insurmountable flaws:

[0004] 1. Photovoltaic cleaning technology: Manual cleaning is labor-intensive, has high maintenance costs, low efficiency, and poses safety risks; fixed spray cleaning consumes a large amount of water, making it unsuitable for the arid photovoltaic concentrated areas in Northwest my country, and direct water washing easily causes dust, mud, and water stains to form, which in turn affects light transmittance; various photovoltaic cleaning robots require matching tracks and moving parts, resulting in high failure rates and maintenance costs in harsh outdoor environments, poor adaptability to complex terrains such as mountains and hills, and slippery conditions in low-temperature and snowy winter environments, making them unable to operate; pure high-pressure air blowing solutions can only remove loose dust and are completely ineffective against stubborn and adhered stains such as bird droppings and salt deposits; self-cleaning coatings suffer from rapid aging, short lifespan, high cost, and insufficient long-term outdoor stability.

[0005] 2. Limitations of existing fluid oscillation cleaning technology: Existing fluid oscillation cleaning solutions based on the Coanda effect are mostly designed for single water media and cannot be compatible with gaseous media. They are subject to water shortages in arid regions, the risk of water circuit freezing and cracking in winter, and the problem of scaling and clogging during long-term operation. Furthermore, they have not been optimized in conjunction with thermal management.

[0006] 3. Deficiencies in photovoltaic thermal management technology: Existing phase change thermal management solutions are mostly based on single materials and single cooling modes, which can only achieve long-term mild temperature control. They have a slow response speed to transient conditions such as extreme high temperatures at noon and sudden hot spots, and cannot quickly suppress the temperature rise. In addition, the thermal management system and the cleaning system are designed completely independently, and the synergistic optimization of energy utilization and timing control has not been achieved.

[0007] 4. Existing gas-liquid combined cleaning solutions are inadequate: Most gas-liquid combined cleaning solutions adopt a dual-nozzle, dual-independent system design, which is complex in structure, difficult to install and maintain, and costly. They have not achieved compatibility of a single oscillator with both gas and liquid media, nor have they formed a deep synergy with photovoltaic thermal management, and thus cannot achieve adaptable application in all climates and all scenarios.

[0008] In summary, the industry urgently needs an integrated and collaborative solution that can simultaneously address the core pain points of photovoltaic clean energy and thermal management, be compatible with both gas and liquid media, adapt to all climates and scenarios, and achieve low energy consumption and low cost. This is also the core technical problem that this invention aims to solve. Summary of the Invention

[0009] The purpose of this invention is to provide a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system and its control method to solve the problems of high water consumption for cleaning, poor scene adaptability, inability to operate in winter, and insufficient transient response of thermal management in the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] (i) Gas-liquid compatible photovoltaic cleaning and thermal management synergistic system

[0012] This system includes:

[0013] Fluid oscillator: Fixed to one side of the light-receiving surface of the photovoltaic module, its swept jet outlet covers the light-receiving surface of the photovoltaic module. Preferably, the fluid oscillator is a self-excited swept oscillator based on the Coanda effect, without moving parts, and can generate stable swept oscillations in both gas and liquid media.

[0014] Gas supply unit and water supply unit: respectively provide high-pressure gas and high-pressure liquid media.

[0015] Medium selection unit: Connected to the inlet of the air supply unit, water supply unit and fluid oscillator respectively, and configured to allow only a single medium to enter the fluid oscillator at any given time.

[0016] As one specific and non-limiting implementation, the media selection unit includes a three-way connector, a first check valve, and a second check valve. The inlet of the first check valve is connected to the gas supply unit, and the outlet is connected to the first branch pipe of the three-way connector, allowing gas to flow only from the gas supply unit to the three-way connector. The inlet of the second check valve is connected to the water supply unit, and the outlet is connected to the second branch pipe of the three-way connector, allowing liquid to flow only from the water supply unit to the three-way connector. Through the installation direction of the check valves, regardless of whether the gas supply unit and the water supply unit are operating simultaneously, any medium entering the three-way connector cannot flow backwards into the pipeline of another medium, thus forming a purely mechanical media isolation.

[0017] More preferably, the opening pressure of the first check valve can be set to be less than the opening pressure of the second check valve, so as to further avoid positive micro-leakage of the second check valve due to pressure fluctuations under low-pressure gas conditions. However, this pressure difference is not a necessary condition for achieving media isolation.

[0018] Thermal management unit: Adhesive to the backsheet side of the photovoltaic module, used to absorb heat from the module and stabilize its operating temperature. As a preferred structure, the thermal management unit includes at least two phase change material layers stacked along the heat flow direction of the backsheet. The first phase change material layer closer to the backsheet side has a higher phase change temperature, and the second phase change material layer farther from the backsheet side has a lower phase change temperature, achieving long-term mild temperature control and secondary heat absorption under extreme operating conditions, while also providing insulation at night.

[0019] Control unit: Connected to the gas supply unit, water supply unit, and thermal management unit respectively, it collects the operating parameters of the photovoltaic modules (such as power and temperature) and environmental parameters (such as sunlight and air temperature), and controls the coordinated operation of each unit based on the parameters.

[0020] (II) A gas-liquid compatible synergistic control method for photovoltaic cleaning and thermal management

[0021] This method is based on the above system and includes the following steps:

[0022] S1. Real-time data acquisition: Collects operating parameters and environmental parameters of photovoltaic modules.

[0023] S2. Working Mode Matching: Matches and triggers preset working modes based on collected parameters. The working modes include, but are not limited to, daily light-soil cleaning mode, heavy-soil cleaning mode, transient strong cooling mode, and low-temperature cleaning mode.

[0024] S3. Coordinated Control Execution: According to the matched working mode, the air supply unit, water supply unit, and thermal management unit are controlled to coordinately execute corresponding operations. For example: the daily light-pollution cleaning mode uses the "air sweep-water sweep-air sweep" sequence; the heavy-pollution cleaning mode uses alternating air and water circulation; the transient strong cooling mode only activates the air supply unit, using forced convection of air jets in conjunction with the thermal management unit for cooling; the low-temperature cleaning mode only activates the air supply unit for snow removal or dust removal.

[0025] S4. Effect Verification and Closed-Loop Optimization: After execution, verify the cleaning and temperature control effects, and optimize the triggering conditions or execution parameters of the working mode. Preferably, an adaptive learning algorithm is used to continuously optimize based on historical data.

[0026] This invention achieves significant benefits such as reduced cleaning water consumption, improved cleaning effect, all-season and all-scenario adaptability, and reduced system energy consumption through a single-oscillator gas-liquid compatible structure, pure mechanical gas-liquid isolation, layered two-phase thermal management, and multi-mode collaborative control. It has extremely strong engineering application value.

[0027] In summary, the present invention has the following beneficial effects:

[0028] 1. Significantly reduces water consumption for cleaning and expands geographical application boundaries. This invention utilizes a single oscillator structure compatible with both gas and liquid media, combined with a dry-wet alternating cleaning mode that first removes air sweeping followed by water sweeping. This allows for the removal of most loose dust from the component surface, with water sweeping only targeting stubborn stains, significantly reducing water consumption per cleaning cycle. Furthermore, the closed-loop water circulation module enables water resource recycling, effectively addressing the core pain point of traditional water washing solutions' poor applicability in arid and water-scarce regions.

[0029] 2. Improves cleaning effectiveness and system reliability, addressing a long-standing technical pain point in the industry. This invention utilizes a layered cleaning mode that alternates between wet and dry cleaning, fundamentally avoiding the problems of dust, mud, water stains, and scale buildup that easily occur with pure water washing. It also effectively removes stubborn, adherent stains such as bird droppings and salt deposits. The system's core cleaning actuator has no moving parts, resulting in a low failure rate during long-term outdoor operation. It also significantly reduces the frequency of water circuit operation, lowering the risk of pipe scaling and blockage, and extending the system's maintenance-free cycle.

[0030] 3. Construct a dual-phase synergistic thermal management system. Dual-phase change materials achieve long-term temperature control under normal operating conditions, high-frequency fluid purging makes up for the shortcomings of transient response, and the cleaning process simultaneously eliminates the hidden danger of hot spots, thus achieving dual efficiency enhancement of cleaning and temperature control.

[0031] 4. Achieving all-season and all-scenario adaptability, expanding the application scope of photovoltaic operation and maintenance systems. This invention allows for pure air sweeping operations in low-temperature winter environments, effectively avoiding the risk of waterway freezing and cracking, making it suitable for photovoltaic operation and maintenance scenarios in northern winters. The system adopts a fixed modular design, eliminating the need for supporting tracks and moving mechanisms, and can adapt to complex terrains such as mountains and hills. It can also meet the application needs of special scenarios such as high altitudes, coastal high-salt-fog environments, and flexible photovoltaic modules.

[0032] 5. Reduces system energy consumption and total lifecycle costs, demonstrating significant engineering application value. The system of this invention enables unattended adaptive operation, greatly reducing manual maintenance costs; its overall structure is simple, installation and maintenance are convenient, and it possesses excellent market prospects. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall system structure in an embodiment of the present invention. In the figure, 1 is a fluid oscillator, 2 is a photovoltaic module, 3 is a thermal management unit, 4 is a control unit, 5 is a gas supply unit, 6 is a first check valve, 7 is a water supply unit, 8 is a second check valve, and 9 is a three-way connector.

[0034] Figure 2 This is a structural diagram of the fluid oscillator 1 in an embodiment of the present invention. In the diagram, 11 is the inlet section, 12 is the inlet throat, 13 is the feedback channel, 14 is the outlet throat, 15 is the outlet expansion section, 16 is the oscillation cavity, and 17 is the flow channel baffle.

[0035] Figure 3 This is a schematic diagram of the internal medium flow state of the fluid oscillator 1 at a certain moment in an embodiment of the present invention;

[0036] Figure 4 This is a schematic diagram of the internal medium flow state of the fluid oscillator 1 at another moment in an embodiment of the present invention;

[0037] Figure 5 This is a flowchart of the control method in an embodiment of the present invention. Detailed Implementation

[0038] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] The core component of this invention includes a fluid oscillator, specifically a Coanda swept fluid oscillator. A Coanda swept fluid oscillator is a fluid device based on the Coanda effect (wall adhesion effect). It contains no moving parts and relies entirely on the fluid's own properties. Under stable inlet pressure conditions, it can generate a self-excited and self-sustaining periodic jet at the outlet, thus inherently possessing high reliability and robustness. It has one inlet, one outlet, two feedback channels, and one coupling cavity. The basic working principle is as follows: Under stable inlet pressure, the main jet enters the coupling cavity from the inlet. Due to the Coanda effect, the main jet randomly adheres to a certain sidewall. Due to the flow restriction effect of the outlet nozzle, some fluid enters the feedback channel and flows back to the control throat, subsequently filling the separation bubble in the coupling cavity. The enlargement of the separation bubble pushes the main jet towards the other sidewall and the feedback channel, repeating the cycle. This results in a periodic oscillating jet at the nozzle with a relatively constant jet velocity and a sweeping oscillation direction within a certain angle range.

[0040] like Figure 1 As shown, a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system includes a fluid oscillator 1, a photovoltaic module 2, a thermal management unit 3, a control unit 4, a gas supply unit 5, a first one-way valve 6, a water supply unit 7, a second one-way valve 8, and a three-way connector 9.

[0041] The main outlet of the three-way connector 9 is sealed and connected to the inlet of the fluid oscillator 1. The first branch pipe of the three-way connector 9 is connected to the outlet of the air supply unit 5, and the second branch pipe is connected to the outlet of the water supply unit 7. The first one-way valve 6 is located between the first branch pipe and the air supply unit 5, and the second one-way valve 8 is located between the second branch pipe and the water supply unit 7.

[0042] The fluid oscillator 1 is fixed to the top frame of the photovoltaic module 2, and the swept jet outlet covers the light-receiving surface of the photovoltaic module 2.

[0043] The photovoltaic module 2 has a light-receiving front facing the light-receiving side and a back heat dissipation surface opposite to the light-receiving front; the thermal management unit 3 is located on the non-light-receiving side of the photovoltaic module 2, and its heat exchange working surface matches the effective heat exchange area size of the back heat dissipation surface of the photovoltaic module 2, and is fixed in a gapless surface contact to form an integrated structure; the control unit 4 is connected to the gas supply unit 5, the water supply unit 7, and the thermal management unit 3 respectively.

[0044] After the gas or liquid medium enters the fluid oscillator 1, it forms a stable self-excited oscillation through the internal dual feedback flow channel, and outputs a high-frequency periodic reciprocating fan-shaped sweeping jet along the height direction of the photovoltaic module 2 from top to bottom and then from bottom to top, so as to cover and clean the light-receiving surface of the photovoltaic module 2.

[0045] like Figure 2The diagram shown is a structural diagram of the fluid oscillator 1, which includes an inlet section 11, an inlet throat 12, a feedback channel 13, an outlet throat 14, an outlet expansion section 15, an oscillation cavity 16, and a flow channel baffle 17. The internal flow channel is optimized for both gas and liquid media, and can form stable self-excited sweeping oscillations for both gas and water media within a certain working pressure range.

[0046] Please combine Figure 3 and Figure 4 The computational fluid dynamics simulation results illustrate the working principle of fluid oscillator 1. Figure 3 and Figure 4 The fluid velocity distribution characteristics within the fluid oscillator 1 at two different times are shown. Under stable inlet pressure, the main jet enters the oscillation chamber 16 from the inlet section 11. Due to the Coanda effect, the main jet randomly adheres to a certain side wall. Due to the flow restriction effect of the outlet throat 14, some fluid enters the feedback channel 13 and flows back to the inlet throat 12, subsequently filling the separation bubble in the oscillation chamber 16. The enlargement of the separation bubble pushes the main jet towards the other side wall and the feedback channel 13. This cycle repeats, thus forming a periodic oscillating jet at the outlet throat 14 with a basically constant jet velocity and a sweeping oscillation direction within a certain angle range. Finally, it flows out from the outlet expansion section 15.

[0047] Preferably, the first check valve 6 is a waterproof check valve, and the second check valve 8 is a gas-proof check valve.

[0048] Specifically, the air supply unit 5 includes an air compressor (not shown in the attached figure), an air storage tank (not shown in the attached figure), and a pressure regulating valve (not shown in the attached figure); the water supply unit 7 includes a closed-loop water circulation module (not shown in the attached figure), a centrifugal pump (not shown in the attached figure), and a filtration module (not shown in the attached figure). The closed-loop water circulation module includes a water collection tank at the bottom of the photovoltaic module 2 (not shown in the attached figure), a multi-stage filtration device (not shown in the attached figure), and a circulating water tank (not shown in the attached figure). The power supply for the air supply unit 5 and the water supply unit 7 can be any one or any combination of three methods: grid power supply, battery power supply, and direct photovoltaic drive.

[0049] like Figure 5 As shown, a gas-liquid compatible photovoltaic cleaning and thermal management synergistic control method is implemented in the following steps:

[0050] Step S1 mainly involves real-time data acquisition: The control unit 4 collects the output voltage, current, surface temperature, local temperature difference, ambient light intensity, ambient temperature, and relative humidity parameters of the photovoltaic module 2 in real time through various sensors at a preset sampling frequency; performs moving average filtering on the collected raw data to eliminate sampling noise; and calculates the output power and power retention rate of the photovoltaic module 2 in real time.

[0051] Step S2 mainly involves working mode matching: the control unit 4 matches and triggers the corresponding working mode according to the collected parameters. The working modes include daily light dirt cleaning mode, heavy dirt and stubborn stain cleaning mode, noon instantaneous strong cooling mode, and winter antifreeze cleaning mode.

[0052] Step S3 mainly involves the execution of collaborative control:

[0053] 1. Daily Light Stain Cleaning Mode: When the power retention rate of photovoltaic module 2 is detected to drop below the preset threshold and the ambient temperature is above 0℃, this mode is triggered: First, the air supply unit 5 is started, and a high-frequency sweeping air jet is output through the oscillator to perform a preset duration of air sweeping to remove loose floating dust on the surface of photovoltaic module 2; after the air sweeping is completed, the power of photovoltaic module 2 is collected again. If the power retention rate recovers to above the preset standard, the cleaning process ends; if it does not meet the standard, the centrifugal pump is started to perform a preset duration of water sweeping, and then the air sweeping is started again to dry the surface of photovoltaic module 2 to avoid water stains and scale.

[0054] 2. Heavy Stain and Stubborn Stains Cleaning Mode: When the power retention rate has not recovered to the preset standard after the daily mode is executed, or when the local temperature difference of photovoltaic module 2 is detected to exceed the preset hot spot warning threshold, this mode is triggered: the alternating cycle of "air sweeping - water sweeping" is used for a preset number of cycles, and finally the panel surface is dried by air sweeping to remove stubborn and adhered stains such as bird droppings and salt and alkali scale.

[0055] 3. Noon Transient Strong Cooling Mode: When the surface temperature of photovoltaic module 2 is detected to exceed the preset high temperature threshold and the ambient light intensity reaches the preset strong light standard, this mode is triggered: the water supply unit 7 is shut down and only the gas supply unit 5 is started. The oscillator outputs a normal temperature swept gas jet, which is executed for a preset duration and repeated at preset intervals to achieve rapid cooling of the surface of photovoltaic module 2. At the same time, the phase change thermal management unit works synchronously to maintain the module's operating temperature in the high-efficiency range.

[0056] 4. Winter antifreeze cleaning mode: When the ambient temperature is detected to be below 0℃, or when snow is detected to be covering the surface of the photovoltaic module 2, this mode is triggered: the water supply unit 7 is shut down throughout the process, and only the air supply unit 5 is started to perform air sweeping operation to remove the snow and dust on the surface, preventing the risk of pipe freezing and cracking or blockage in low temperature environment.

[0057] Step S4 mainly involves effect verification and closed-loop optimization: After each mode execution, the operating parameters of photovoltaic module 2 are collected to verify the cleaning and temperature control effects; through adaptive learning algorithms, based on historical operating data, environmental parameters and execution effects, the mode trigger threshold, execution time and number of cycles are continuously optimized to further reduce system operating energy consumption and improve photovoltaic module power generation efficiency.

[0058] To achieve closed-loop optimization in step S4, this system employs an adaptive learning algorithm based on performance feedback. The following explanation uses a preferred, non-limiting implementation as an example:

[0059] Define the optimization objective function J = E / P rec Where E is the total energy consumed in a single cleaning or temperature control operation, including the power consumption of the air compressor and water pump, and P rec This represents the power increment recovered by the photovoltaic module after the action (unit: kWh). The goal is to minimize J, i.e., to achieve the highest power generation gain with the lowest energy consumption.

[0060] The algorithm flow is as follows:

[0061] 1. Initialization: Set default trigger thresholds (e.g., power retention rate 92%), execution duration (e.g., air sweep 60s) and number of cycles for each working mode (daily light pollution, heavy pollution, strong cooling, low temperature).

[0062] 2. Data Recording: After each execution, record environmental parameters (temperature, light intensity, estimated dust accumulation), actual execution parameters, total energy consumed (E), and the power increment (P) recovered by the photovoltaic modules. rec .

[0063] 3. Threshold Update: An exponentially weighted moving average method is used to smoothly update the trigger threshold Th.

[0064] Th new =α‧Th current +(1-α)‧Th optimal

[0065] Among them Th optimal To find the threshold that minimizes J based on the most recent N historical data points, Th current It is the current trigger threshold, Th new It is the trigger threshold for the next update, and α is a smoothing factor, which can take values ​​between 0.6 and 0.8.

[0066] 4. Execution time optimization: For the gas sweep time t, a linear regression method can be used to analyze the relationship between t and power recovery rate in historical data, find the inflection point of marginal benefit decline, and set the time to the value corresponding to that inflection point.

[0067] 5. Convergence Determination: When the rate of change of J is less than a preset threshold after multiple consecutive adjustments, it is considered that the optimal strategy has been converged, and large-scale adjustments are stopped, with only fine-tuning performed. In one embodiment, the preset threshold is set to 1%.

[0068] The following is a further explanation with reference to specific embodiments.

[0069] Example 1

[0070] This embodiment mainly involves a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system. The system is adapted to a 1MW centralized ground-mounted photovoltaic power station in the Gobi Desert region of Northwest my country. The power station uses 550W monocrystalline silicon photovoltaic modules 2. The dimensions of a single module are 2278mm×1134mm. 20 modules are arranged in a string horizontally with an installation tilt angle of 38°. The application scenario is characterized by drought, frequent sandstorms, extreme winter temperatures of -18℃, and large diurnal temperature differences. It has stringent requirements for the system's water conservation, antifreeze properties, high reliability, and adaptability to all scenarios.

[0071] The specific system structure, connection relationships, and parameters of this embodiment are as follows:

[0072] 1. Core Execution Unit: A fluid oscillator 1 is used, with one oscillator corresponding to each photovoltaic module 2. The oscillator is made of 6061 aluminum alloy and is CNC machined in one piece, with overall dimensions of 2300mm×60mm×30mm. It is an integrated double-layer sealed structure with an overall sealing pressure resistance ≥1.0MPa. Its internal flow channel is optimized for gas-liquid dual media, with specific structural parameters as follows: the inlet section 11 adopts a tapered structure with a contraction angle of 15°; the inlet throat 12 is 4mm wide and 6mm high, with a width-to-height ratio of 1:1.5; the oscillation chamber 16 is 30mm long and 12mm wide; the dual feedback channels 13 are symmetrically arranged around the oscillation chamber 16, with a channel width of 3mm and a height of 4mm, with a width-to-height ratio of 1:1.33; the outlet throat 14 is 5mm wide and 7mm high, with a width-to-height ratio of 1:1.4; and the outlet expansion section 15 has an expansion angle of 30°, matching the jet sweep angle. Performance testing showed that this oscillator can form stable self-excited sweeping oscillations in both gas and water media under working pressures of 0.2~0.5MPa, with a sweeping frequency of 80~120Hz and an effective jet coverage length of 1200mm, which can completely cover the entire light-receiving surface of a single photovoltaic module 2 without any cleaning blind spots.

[0073] 2. Gas-liquid input and mechanical interlock unit: including a three-way connector 9, a first check valve 6, and a second check valve 8. The three-way connector 9 is made of 304 stainless steel, with a main pipe inner diameter of 10mm and two branch pipe inner diameters of 8mm. The main pipe outlet is sealed to the inlet of the fluid oscillator 1 via a flange (not shown in the attached diagram). The first branch pipe is connected to the outlet of the gas supply unit 5 via the first check valve 6, and the second branch pipe is connected to the outlet of the water supply unit 7 via the second check valve 8. The first check valve 6 is a waterproof brass check valve, whose sealing material and structure effectively prevent backflow of liquid, with an opening pressure of 0.1MPa and a sealing pressure resistance of 1.6MPa. The second check valve 8 is a gas-proof stainless steel check valve, whose sealing pair effectively prevents backflow of gas, with an opening pressure of 0.2MPa. The opening pressure difference between the two is 0.1MPa.

[0074] 3. Power Supply Unit: Includes air supply unit 5 and water supply unit 7. Air supply unit 5 uses a photovoltaic direct-drive air compressor (not shown in the attached diagram), with its power supply directly connected to the DC combiner box of photovoltaic module 2 (not shown in the attached diagram). It prioritizes the use of surplus photovoltaic power for driving, and its output pressure is adjustable from 0 to 0.8 MPa. It is equipped with a 1 m³ pressure storage tank (not shown in the attached diagram) and a 0.5-grade precision pressure regulating valve (not shown in the attached diagram), capable of stably supplying high-pressure gas of 0.2 to 0.5 MPa to all 20 oscillators in the string. Water supply unit 7 uses a photovoltaic direct-drive centrifugal pump (not shown in the attached diagram), with a rated head of 50 m and a rated flow rate of 2 m³ / h. It is equipped with a closed-loop water circulation module, including a continuous water collection tank (not shown in the attached diagram) located at the bottom of photovoltaic module 2, a filter device (not shown in the attached diagram), and a 5 m³ circulating water tank (not shown in the attached diagram). Clean return water is filtered and recycled to meet the long-term anti-clogging requirements of the oscillator flow channels.

[0075] 4. Thermal Management Unit 3: Utilizing a vertically layered, stacked dual-phase change material integrated structure, it is fixedly attached to the backsheet side of each photovoltaic module 2. Its overall dimensions match the effective heat exchange area of ​​the photovoltaic module 2, with no splicing gaps. The unit contains two independently sealed phase change containers. These containers are made of 0.5mm thick 6061 aluminum alloy stamped shells, internally vacuum-degassed and filled with the corresponding phase change material, then laser-welded for complete sealing. An internal graphite foam high thermal conductivity reinforcement is also included.

[0076] The phase change container on the side furthest from the backsheet of photovoltaic module 2 is filled with octadecane solid-liquid phase change material with a melting point of 16℃, a latent heat of phase change of 243kJ / kg, and a filling thickness of 10mm. The phase change container on the side closer to the backsheet of photovoltaic module 2 is filled with paraffin-based composite phase change material with a melting point of 36℃, a latent heat of phase change of 210kJ / kg, and a filling thickness of 15mm. A 1mm thick high thermal conductivity graphite sheet is used to fill and bond the phase change containers to the photovoltaic backsheet and between the two phase change containers, thereby reducing contact thermal resistance and ensuring continuous heat transfer. The unit is equipped with three PT100 platinum resistance temperature acquisition components, evenly distributed in the upper, middle, and lower areas of the module backsheet, with a temperature measurement accuracy of ±0.2℃, and connected to the control unit 4 in real time.

[0077] 5. Control Unit 4: It adopts a PLC controller (not shown in the attached figure), equipped with a 4G wireless communication module, a sampling frequency of 1Hz, and collects the output voltage, current, surface temperature and other operating parameters of the photovoltaic module 2 in real time. It has a built-in adaptive learning control algorithm and can output control commands to the gas supply unit 5, water supply unit 7 and thermal management unit 3 to realize unattended collaborative operation in all weather conditions.

[0078] In this embodiment, both the first one-way valve 6 and the second one-way valve 8 are installed in the direction from their respective power units toward the three-way connector 9. When only the high-pressure air supply unit 5 is activated, the high-pressure gas pushes open the first one-way valve 6 in the forward direction and enters the three-way connector 9 and the fluid oscillator 1. At this time, the gas in the three-way connector 9 acts in the reverse direction on the outlet end of the second one-way valve 8. Due to the one-way shut-off characteristic of the second one-way valve 8, the gas cannot enter the pipeline of the high-pressure water supply unit 7. Similarly, when only the high-pressure water supply unit 7 is activated, the high-pressure water pushes open the second one-way valve 8 in the forward direction, while the first one-way valve 6 shuts off in the reverse direction, preventing water from flowing back into the air supply pipeline. The control unit 4 also ensures at the software level that the air supply unit 5 and the water supply unit 7 will not be activated simultaneously, forming a double interlock.

[0079] In this embodiment, the opening pressure of the first check valve 6 (0.1 MPa) is less than the opening pressure of the second check valve 8 (0.2 MPa). This pressure difference is not a necessary condition for achieving media isolation, but as a preferred design, it can prevent residual water pressure that may exist in the water supply unit pipeline from pushing open the second check valve 8 in the positive direction when the air supply pressure is low (e.g., the air supply pressure is between the two opening pressures), thus avoiding micro-leakage of gas and liquid. The electronic interlock that prevents the air supply unit 5 and the water supply unit 7 from starting simultaneously already ensures basic safety, and the pressure difference provides additional mechanical protection.

[0080] Example 2

[0081] This embodiment mainly relates to the collaborative control method of a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system. It is based on the system implementation described in Embodiment 1. The application scenario is a 20kW distributed household photovoltaic power station in the North China Plain, which uses 40 540W monocrystalline silicon photovoltaic modules with an installation tilt angle of 35°. The application scenario is characterized by frequent sandstorms, and the surface of the modules is prone to the accumulation of loose floating dust, sticky bird droppings, and salt and alkali scale. The ambient temperature during the operation period is 5~35℃, with no risk of icing.

[0082] The specific implementation steps of this embodiment are as follows:

[0083] 1. Step S1 Real-time data acquisition: The control unit 4 collects the output voltage, current, surface temperature, local temperature difference, ambient light intensity, ambient temperature, and relative humidity parameters of the photovoltaic module 2 in real time at a sampling frequency of 1Hz; the sampling noise is eliminated by moving average filtering, and the actual output power and power retention rate of the photovoltaic module 2 are calculated in real time. The power retention rate is the ratio of the actual output power of the module to the clean state reference power, wherein the clean state reference power is the theoretical output power of the photovoltaic module after correction based on the real-time light intensity and ambient temperature.

[0084] 2. Step S2 Working Mode Matching: Initially, it is detected that the power retention rate of photovoltaic module 2 has dropped below 92%, and the ambient temperature is 22℃, which meets the triggering conditions of the daily light dirt cleaning mode, and the mode is triggered to execute. After the daily light dirt cleaning mode is executed, it is detected that the power retention rate of the module has only recovered to 95%, which has not reached the preset standard of 98%. At the same time, it is detected that the maximum local temperature difference of the module has reached 8℃, which exceeds the preset hot spot warning threshold of 5℃. Then, the heavy dirt and stubborn stain cleaning mode, namely the water and air alternating circulation cleaning mode, is triggered.

[0085] 3. Step S3: Cooperative control execution:

[0086] Routine light-duty cleaning mode execution: Step 1: Activate air supply unit 5, adjust output pressure to 0.3MPa, and output high-frequency sweeping air jets through fluid oscillator 1 for 60 seconds to remove more than 85% of loose dust from the component surface; after the air sweeping ends, allow it to stand for 30 seconds, and collect component power parameters. The power retention rate only recovers to 94%, which does not meet the preset standard, so the water sweeping process is immediately initiated. Step 2: Activate water supply unit 7, adjust output pressure to 0.35MPa, and perform water sweeping for 30 seconds to impact residual adhered stains through sweeping water jets. Step 3: Turn off water supply unit 7, and activate air supply unit 5 again to perform air sweeping for 90 seconds to thoroughly dry water stains on the component surface and prevent water stain residue from forming scale.

[0087] Heavy-duty and stubborn stain cleaning mode: The "air sweep - water sweep" alternating cycle is adopted, with 3 cycles. The working pressure of the air circuit is kept stable at 0.3MPa and the working pressure of the water circuit is kept stable at 0.35MPa. The stubborn and adhered stains are broken down by alternating air and liquid jet impact, avoiding the dust and mud problems caused by continuous water washing. After the cycle is completed, the water supply unit 7 is turned off, and the final air sweep is performed for 120 seconds to ensure that there are no water stains left on the surface of the components.

[0088] 4. Step S4 Effect Verification and Closed-Loop Optimization: After the mode is executed, let it stand for 60 seconds and collect the operating parameters of photovoltaic module 2. The module power retention rate is restored to 99.2%, and the local maximum temperature difference is reduced to less than 2℃, and the cleaning effect meets the standard. The control unit 4, through an adaptive learning algorithm, optimizes the trigger threshold of the daily light dirt cleaning mode to a power retention rate of less than 93% and the air sweeping time to 50 seconds based on the execution data, thereby reducing system energy consumption while ensuring the cleaning effect. The total water consumption of this cleaning cycle is reduced by 72% compared with the traditional fixed spray solution, and the water saving effect is significant.

[0089] Example 3

[0090] This embodiment mainly relates to a collaborative control method for a gas-liquid compatible photovoltaic cleaning and thermal management collaborative system. Based on the system implementation described in Embodiment 1, the application scenario is a 10MW centralized photovoltaic power station in the cold region of Northeast my country, where the lowest ambient temperature in winter is -25℃ and the extreme maximum temperature on the surface of the modules at noon in summer can reach 65℃. This embodiment completes the winter antifreeze cleaning and summer noon transient strong cooling work through a single gas medium mode. The water supply unit 7 is shut down throughout the process, and the fluid oscillator 1 is driven only by the gas supply unit 5.

[0091] Scenario A: Winter antifreeze cleaning single-gas mode

[0092] 1. Step S1 Real-time data acquisition: The control unit 4 collects ambient temperature, photovoltaic module 2 surface temperature, light intensity, module output power, and surface snow cover status parameters in real time at a sampling frequency of 1Hz.

[0093] 2. Step S2 Working Mode Matching: The ambient temperature is detected to be -8℃, the snow thickness on the component surface reaches 5mm, and the power retention rate drops to 85%, which meets the triggering conditions of the winter antifreeze cleaning mode. The mode is triggered to execute, and the water supply unit 7 and the water circuit shut-off valve (not shown in the attached figure) are locked throughout the process, and only single gas medium operation is used.

[0094] 3. Step S3 Coordinated Control Execution: Start the air supply unit 5, adjust the output pressure to 0.4MPa, output a high-frequency sweeping air jet through the fluid oscillator 1, and perform continuous air sweeping for 180s to remove large areas of snow on the component surface; for local areas with thicker snow accumulation, instantly increase the output pressure to 0.5MPa and perform fixed-point enhanced sweeping for 30s to thoroughly remove the bottom layer of compacted snow and dust; the water supply unit 7 is shut off throughout the operation to effectively avoid the risk of pipe freezing and blockage in low-temperature environments.

[0095] 4. Step S4 Effect Verification and Closed-Loop Optimization: After the operation was completed, the snow on the surface of photovoltaic module 2 was completely removed, the power retention rate was restored to 98.5%, and the cleaning effect met the standard. Based on the data from this low-temperature operation, control unit 4 optimized the snow thickness trigger threshold to 3mm and the conventional air sweeping working pressure to 0.35MPa, reducing the energy consumption of air compressor operation while ensuring the snow removal effect.

[0096] Scenario B: Noon transient rapid cooling single-gas mode

[0097] 1. Step S1 Real-time data acquisition: The control unit 4 collects the surface temperature of the photovoltaic module 2, ambient light intensity, and module output power parameters in real time at a sampling frequency of 2Hz.

[0098] 2. Step S2 Working Mode Matching: During the summer noon period of 12:30-13:30, the surface temperature of photovoltaic module 2 was detected to reach 58℃, exceeding the preset high temperature threshold of 55℃, and the ambient light intensity reached 1100W / m². 2 It meets the preset strong light standard, triggers the noon transient strong cooling mode, shuts down the water supply unit 7 throughout the process, and only uses a single gas medium to purge and cool.

[0099] 3. Step S3 Coordinated Control Execution: The water supply unit 7 is shut down, the air supply unit 5 is started, the output pressure is adjusted to 0.25MPa, and a normal temperature sweeping air jet is output through the fluid oscillator 1. The single purging time is 40s, and the process is repeated at 5min intervals to continuously suppress the sudden rise in module temperature. Simultaneously, the thermal management unit 3 is linked, and the 36℃ high-temperature phase change material near the backsheet is completely melted. Through the latent heat of phase change, it continuously absorbs the core heat of the module, locking the module temperature in the high-efficiency range. The outer 16℃ low-temperature phase change material assists in uniform heat conduction, avoiding the formation of local hot spots, while buffering the sudden temperature drop caused by the air sweep to avoid thermal shock to the module. The transient purging of the air jet and the long-term temperature control of the phase change material work together to stabilize the module operating temperature in the high-efficiency power generation range below 45℃.

[0100] 4. Step S4 Effect Verification and Closed-Loop Optimization: During the execution of this mode, the highest surface temperature of photovoltaic module 2 does not exceed 43℃, which is more than 15℃ lower than the temperature of the control group without temperature control measures, and the power generation efficiency of the module is improved by 6.8%. Based on historical high temperature operating data, control unit 4 optimizes the high temperature trigger threshold to 53℃, the single purging time to 30s, and the interval time to 4min, which further reduces the system's operating energy consumption while ensuring the temperature control effect.

[0101] Example 4

[0102] This embodiment mainly relates to a collaborative control method for a gas-liquid compatible photovoltaic cleaning and thermal management system, specifically involving the adaptive learning method in step S4. This embodiment uses the daily light-pollution cleaning mode from Embodiment 2 as an example, and the system recorded data from 15 consecutive cleaning operations. The initial trigger threshold was a power retention rate of 92%, with air sweeping for 60 seconds, water sweeping for 30 seconds, and drying for 90 seconds. After the first 5 executions, the average power generation gain per unit energy consumption, J, was 0.23 kWh / kWh. Based on historical data, the algorithm found that when the trigger threshold was lowered to 93%, although the execution frequency increased slightly, J decreased to 0.18 kWh / kWh because the components maintained a high power output for a long time, and the cleaning time could be shortened (air sweeping 50 seconds, water sweeping 25 seconds, drying 70 seconds). From the 6th execution onwards, the system automatically updated the threshold to 93%, and the duration was shortened proportionally. After the 12th execution, J stabilized at 0.17 kWh / kWh, and the algorithm determined convergence. Ultimately, the system saved 72% of water and 18% of electricity compared to the initial state.

[0103] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A gas-liquid compatible photovoltaic cleaning and thermal management synergistic system, characterized in that, include: At least one fluid oscillator (1) is fixed to one side of the light-receiving surface of the photovoltaic module (2), and its sweeping jet outlet covers the light-receiving surface of the photovoltaic module (2); Gas supply unit (5) and water supply unit (7); The medium selection unit is connected to the inlet of the gas supply unit (5), the water supply unit (7) and the fluid oscillator (1), respectively; the medium selection unit is configured to allow only a single medium in gas or liquid to enter the fluid oscillator (1) at any given time. A thermal management unit (3) is attached to the back panel side of the photovoltaic module (2); The control unit (4) is connected to the gas supply unit (5), the water supply unit (7) and the thermal management unit (3) respectively, and is used to collect the operating parameters and environmental parameters of the photovoltaic module (2), and control the coordinated operation of the gas supply unit (5), the water supply unit (7) and the thermal management unit (3) based on the parameters.

2. The system according to claim 1, characterized in that, The medium selection unit includes: The tee connector (9) has its main outlet connected to the inlet end of the fluid oscillator (1); The first one-way valve (6) has its inlet end connected to the gas supply unit (5) and its outlet end connected to the first branch pipe of the three-way connector (9), which is used to ensure that gas can only flow from the gas supply unit (5) to the three-way connector (9). The second one-way valve (8) has its inlet end connected to the water supply unit (7) and its outlet end connected to the second branch pipe of the three-way connector (9), which is used to ensure that liquid can only flow from the water supply unit (7) to the three-way connector (9).

3. The system according to claim 2, characterized in that, The opening pressure of the first check valve (6) is less than the opening pressure of the second check valve (8), and the difference between the two opening pressures is not less than 0.05MPa; the first check valve (6) is a waterproof check valve, and the second check valve (8) is an anti-gas-channeling check valve.

4. The system according to claim 1, characterized in that, The fluid oscillator (1) is a self-excited sweeping oscillator based on the Coanda effect. Its internal flow channel is designed with universality, and it can generate stable self-excited sweeping oscillations for both gas and liquid media within a preset working pressure range.

5. The system according to claim 1, characterized in that, The thermal management unit (3) includes at least two phase change material layers stacked along the heat flow direction of the backsheet of the photovoltaic module (2); wherein the phase change temperature of the first phase change material layer closer to the backsheet is higher than the phase change temperature of the second phase change material layer farther from the backsheet.

6. The system according to claim 5, characterized in that, The phase transition temperature of the first phase change material layer is 35℃~37℃, and the phase transition temperature of the second phase change material layer is 15℃~17℃; the phase change material layer is internally distributed with a high thermal conductivity reinforcement.

7. The system according to claim 1, characterized in that, The air supply unit (5) includes an air compressor; the water supply unit (7) includes a closed-loop water circulation module, which includes a water collection tank and a circulating water tank located at the bottom of the photovoltaic module (2).

8. A gas-liquid compatible photovoltaic cleaning and thermal management synergistic control method based on the system described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Real-time acquisition of operating parameters and environmental parameters of photovoltaic module (2); S2. Match and trigger the preset working mode based on the collected parameters; S3. According to the working mode, control the gas supply unit (5), water supply unit (7) and thermal management unit (3) to perform the corresponding operations in coordination; S4. After execution, verify the effect and optimize the triggering conditions or execution parameters of the working mode.

9. The method according to claim 8, characterized in that, The working mode includes at least one of the following: daily light dirt cleaning mode, heavy dirt cleaning mode, transient strong cooling mode, and low temperature cleaning mode; The daily light-dirt cleaning mode adopts a "air sweep-water sweep-air sweep" sequence logic; The heavy-duty cleaning mode adopts the logic of "alternating air sweeping and water sweeping"; The transient strong cooling mode only activates the gas supply unit (5) and uses forced convection of air jet in conjunction with the thermal management unit (3) to cool down; The low-temperature cleaning mode only activates the air supply unit (5) for snow removal or dust removal.

10. The method according to claim 8, characterized in that, In step S4, an adaptive learning algorithm is used to continuously optimize the trigger threshold, execution duration, or number of cycles of the working mode based on historical operating data and execution results. The adaptive learning algorithm includes at least the following steps: establishing an objective function with the goal of minimizing energy consumption under unit power generation gain, collecting the power recovery rate and actual energy consumption after each execution, and updating the trigger threshold using an exponentially weighted moving average method so that the threshold gradually converges to the optimal value.

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