Photovoltaic module-inverter dual-temperature control system and control method and air energy water heater

Abstract

The invention discloses a dual-temperature cooperative control system and method for a photovoltaic module and an inverter and an air energy water heater. The dual-temperature cooperative control system of the photovoltaic module and the inverter comprises an inverter and heat dissipation module composed of the inverter and a first phase change material heat exchange structure, a photovoltaic module and heat dissipation module composed of the photovoltaic module and a second phase change material heat exchange structure, and a control monitor. A cooling working medium sequentially flows through the first phase-change material heat exchange structure and the second phase-change material heat exchange structure for heat exchange, then enters the heat exchanger for heat exchange and cooling, and circularly exchanges heat; and the control monitor monitors the working temperatures of the inverter and the photovoltaic module and controls the flow of the cooling working medium, so that the inverter and the photovoltaic module work at a safe temperature. Two phase-change materials with different phase-change temperatures are adopted to perform heat exchange on the inverter and the photovoltaic module respectively, and after the same cooling working medium performs heat exchange on the two phase-change materials, the problem of thermal interference between the inverter and the photovoltaic module is solved, and the conversion efficiency and the stability of the system are improved.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power generation technology, and in particular to a dual-temperature coordinated control system and control method for photovoltaic modules and inverters in a photovoltaic thermal system (PVT), and an air source water heater including a photovoltaic thermal system. Background Technology

[0002] A photovoltaic (PV) power generation system is a system that directly converts solar energy into electrical energy. Please refer to [link / reference]. Figure 1 The system mainly includes photovoltaic (PV) modules, PV combiner boxes, inverters, array supports, and electrical equipment and system balancing. PV modules directly convert sunlight into direct current (DC); PV combiner boxes collect DC power; and inverters convert DC to alternating current (DC / AC), transforming DC into sinusoidal AC power that is synchronized with the grid frequency, phase, and amplitude. Array supports fix the PV modules at optimal angles to ensure stability, safety, and maximize solar radiation reception. Electrical equipment and system balancing are used for AC power distribution and grid connection, as well as for data and operational optimization of the monitoring system. Alternatively, energy storage batteries can be selected to store excess energy. This allows for discharge at night or on cloudy days, enabling self-consumption or serving as a backup power source, improving power supply reliability and economy.

[0003] The entire photovoltaic (PV) power generation system follows a clear path: "PV power generation → DC collection → Inverter conversion → Grid connection / self-consumption." Its intelligent core lies in the inverter's MPPT (Maximum Power Point Test) function, which, like an "eagle eye," tracks the maximum output power of the modules in real time under current sunlight and temperature, ensuring the system always generates power at peak efficiency. PV power generation systems can operate grid-connected, most commonly with the generated energy prioritized for self-consumption, surplus sold to the grid, and drawn from the grid when insufficient. This is the mainstream choice for homes and power plants. They can also operate off-grid, i.e., independently, but must be equipped with energy storage batteries for remote areas without grid coverage, communication base stations, etc. A PV power generation system is a highly efficient, modular, and intelligent clean energy solution. From a few watts of solar streetlights to hundreds of megawatts of ground-mounted power plants, the core principle remains the same; only the scale and configuration differ.

[0004] With the advancement of science and technology, single photovoltaic power generation systems have evolved into systems that combine photovoltaic power generation and solar collectors—Photovoltaic Thermal (PVT) systems. (Please refer to...) Figure 2Photovoltaic thermal systems convert solar radiation into both heat and electricity, significantly improving the overall efficiency of solar energy utilization and reducing system costs. Essentially, a photovoltaic (PV) thermal system is a "photovoltaic + solar thermal" dual-function device. It includes photovoltaic modules (PV cells) that directly convert sunlight into direct current (DC); a collector that absorbs waste heat generated during PV cell power generation and unused solar thermal energy. This heat-absorbing unit is located on the back of the PV cells; a cooling medium and circulation system that flows through the collector to absorb heat. The cooling medium is typically water or antifreeze, acting as a heat carrier to carry away and utilize the heat energy; an insulation layer and outer shell to reduce heat loss to the environment; an insulation unit to ensure effective heat collection; heat storage and utilization terminals, such as hot water tanks, radiators, and underfloor heating coils; a heat utilization unit that stores and uses heat; and auxiliary systems, including pumps, controllers, piping, and an inverter control and conversion unit that converts DC to AC to ensure automatic and efficient system operation. A photovoltaic thermal system is both a power generation panel and a heat collection panel.

[0005] When sunlight shines on the photovoltaic modules, the photovoltaic layer immediately begins generating electricity. Simultaneously, the heat from solar radiation and waste heat generated during photovoltaic power generation are absorbed by the heat collection layer beneath the modules. A circulation pump is activated, and a cooling medium (such as water or antifreeze) flows through channels within the heat collection layer, carrying away the heat. The direct current (DC) electricity generated by the photovoltaic cells is converted to alternating current (AC) by an inverter, which can then be used for household purposes or fed into the grid. Meanwhile, the heated medium flows into a hot water storage tank, providing hot water for domestic washing, heating, and other uses. The cooling process significantly reduces the operating temperature of the photovoltaic cells. For every 1°C decrease in the temperature of the photovoltaic cells, their power generation efficiency typically increases by approximately 0.3%-0.5%. The photovoltaic thermal system is a highly efficient integrated solar energy utilization solution.

[0006] However, in existing technologies, excessively high photovoltaic (PV) module temperatures lead to a decrease in power generation efficiency; specifically, for every 1°C increase in temperature, efficiency decreases by 0.3%-0.5%. As the core equipment of a PV system, the inverter's operating temperature directly affects the operating temperature of the PV modules. Due to the mismatch in the operating temperature ranges of the PV modules and inverters, thermal interference occurs between the devices, severely impacting the conversion efficiency and stability of the PV modules. To overcome this thermal interference defect between PV modules and inverters, existing technologies typically employ: 1. Installing PV modules on outdoor supports and installing the inverter in a cool, well-ventilated location to avoid thermal interference; 2. Using heat dissipation devices, such as passive cooling, where the inverter's casing uses high thermal conductivity materials and structures (e.g., aluminum alloy finned heat sinks) to dissipate heat through natural convection with the air. Active cooling methods also exist, where, in high-temperature environments (such as desert areas), the inverter is equipped with intelligent fans that automatically start and stop based on temperature, or liquid cooling systems are used, which are already being tested in large-scale projects. While traditional temperature control methods for photovoltaic modules and inverters, such as air cooling and water cooling, have some effectiveness, they suffer from high energy consumption and complex maintenance. Furthermore, photovoltaic module temperature control and inverter temperature control are independently configured, and their operating temperature ranges differ. If airflow or water is directly used as the cooling medium to sequentially exchange heat with the inverter and photovoltaic modules, the use of the same cooling medium for both devices makes it impossible to precisely control their different operating temperatures. This results in unresolved thermal interference between the devices, ultimately reducing the conversion efficiency and stability of the photovoltaic modules.

[0007] Therefore, overcoming the mismatch in the operating temperature ranges of existing photovoltaic modules and inverter modules, which leads to thermal interference between the devices and reduces the conversion efficiency and stability of photovoltaic modules, is an urgent problem to be solved in this field. Summary of the Invention

[0008] This invention addresses the technical problem of mismatched operating temperature ranges between photovoltaic (PV) modules and inverters, leading to thermal interference and reduced conversion efficiency and stability of PV modules. It provides a dual-temperature coordinated control system and method for PV modules and inverters in a PV thermal system, including an air-source heat pump water heater. This invention achieves dual-temperature coordinated control of PV modules and inverters based on two phase change materials with different phase change temperatures. This allows the PV modules and inverters to operate collaboratively within their optimal temperature ranges, resulting in high system efficiency and low cost.

[0009] This invention provides a dual-temperature coordinated control system for photovoltaic modules and inverters, characterized in that it includes an inverter and a heat dissipation module composed of an inverter and a first phase change material heat exchange structure, a photovoltaic module and a heat dissipation module composed of a photovoltaic module and a second phase change material heat exchange structure, and a control monitor; the cooling medium first flows through the first phase change material heat exchange structure for heat exchange, then flows through the second phase change material heat exchange structure for heat exchange, and then enters the heat exchanger for heat exchange and cooling, and circulates for heat exchange; the control monitor monitors the operating temperature of the inverter and the photovoltaic module and controls the flow rate of the cooling medium, so that the inverter and the photovoltaic module operate at a safe temperature.

[0010] Preferably, it also includes a circulating pump located between the inverter, the heat dissipation module, and the heat exchanger; temperature sensors located on the inverter and the photovoltaic module respectively; the cooling working fluid exchanging heat with external circulating water in the heat exchanger for cooling; and the control monitor being electrically connected to the temperature sensors and the circulating pump.

[0011] By employing two phase change materials with different phase change temperatures for heat exchange and cooling of the inverter and photovoltaic modules respectively, the system cleverly meets the unique requirements that the temperature control of the photovoltaic modules and the inverter are independently set and that their operating temperature ranges are different. When the same cooling medium is used to exchange heat between the two devices with different phase change temperatures, the inverter and photovoltaic modules can be automatically and precisely controlled to operate efficiently at different temperatures. Therefore, it effectively overcomes the shortcomings of existing technologies that cannot simultaneously meet the independent temperature control requirements of the inverter and photovoltaic modules, solves the thermal interference problem caused by temperature conflicts between the two devices, and avoids mutual influence. This improves the conversion efficiency and stability of the photovoltaic modules. The power system is directly obtained from the photovoltaic modules, eliminating the need for additional power. System operating efficiency is improved, and costs are reduced.

[0012] Preferably, the first phase change material heat exchange structure is isolated from the inverter through a heat-conducting layer, and the second phase change material heat exchange structure is isolated from the photovoltaic module through a heat-conducting layer.

[0013] Preferably, the first phase change material heat exchange structure includes a first phase change material layer and a cooling working medium channel disposed around the first phase change material layer; the second phase change material heat exchange structure includes a second phase change material layer and a cooling working medium channel disposed around the second phase change material layer.

[0014] A thermally conductive layer is used to isolate the phase change material from the heat-generating device, and a pipe for the flow of cooling fluid is set around the phase change material. The heat from the heat-generating device can be conducted to the phase change material through the thermally conductive layer, and the cooling fluid flows and exchanges heat through the pipes around the phase change material, but does not come into direct contact with the heat-generating device. This allows for safe and efficient heat transfer and cooling.

[0015] Preferably, the phase change material is one of organic phase change materials, inorganic phase change materials, or composite phase change materials.

[0016] Preferably, the phase change material is a composite phase change material; the phase change temperature of the first phase change material is 45±2℃, and the phase change temperature of the second phase change material is 48±2℃.

[0017] Mature phase change materials are selected, with priority given to composite phase change materials, which facilitates the modulation of suitable phase change temperatures and is suitable for electronic products.

[0018] Preferably, the thermally conductive layer is prepared from one of thermally conductive silicone, extruded polystyrene, polyurethane foam, or aerogel felt.

[0019] The selected heat-conducting material is readily available and can facilitate safe and efficient heat exchange.

[0020] The control method for the dual-temperature coordinated control system of photovoltaic modules and inverters provided by the present invention includes the following control steps:

[0021] Step 1: Set the default flow rate of the circulating pump, start the system, and monitor the temperature of the inverter and the photovoltaic module at predetermined intervals;

[0022] Step 2: Determine whether the temperature of the inverter and the photovoltaic module are within their respective safe temperature ranges; and prioritize the inverter and photovoltaic module that exceed the safe temperature range by the most to adjust the flow rate of the circulation pump; if the temperature of the inverter and the photovoltaic module are both within their respective safe temperature ranges, maintain the flow rate of the circulation pump.

[0023] Step 3: When the flow rate is increased, and the temperature of the inverter and the photovoltaic module are both detected to be within the safe temperature range twice in a row, reduce the adjustment range of the circulation pump flow rate; when the flow rate is increased, and the temperature of the inverter or the photovoltaic module is detected to be higher than the upper limit of the safe temperature range twice in a row, handle it as an abnormal state.

[0024] Step 4: When the temperature of the inverter or the temperature of the photovoltaic module are higher than the specified temperature and remain higher for a specified time, handle the abnormal state as described above, adjust the circulation pump to the maximum flow rate, reduce the power generation of the photovoltaic module to 70% of the rated power, and trigger an alarm for "heat dissipation overload".

[0025] The control method of this invention can be precisely matched with the dual-temperature coordinated control system for photovoltaic modules and inverters proposed in this invention. By automatically and in real-time monitoring the operating temperatures of the photovoltaic modules and inverters through a control monitor, and adjusting the flow rate of the circulating pump to ensure timely heat exchange and cooling of both, the system operates within its respective safe temperature range. This avoids thermal interference problems caused by temperature conflicts between the inverter and photovoltaic modules, thereby improving the conversion efficiency and stability of the photovoltaic modules. Furthermore, an abnormal state handling and alarm mechanism is included to ensure the safe and reliable operation of the system.

[0026] Preferably, the default flow rate is 50% of the rated flow rate; the scheduled time is 4-6 seconds.

[0027] Preferably, the safe temperature range of the inverter is 44.5℃~45.5℃; and the safe temperature range of the photovoltaic module is 47.5℃~48.5℃.

[0028] Preferably, the flow rate of the circulating pump is adjusted to 5% to 10% of the rated flow rate.

[0029] Preferably, the inverter is limited to a temperature of 48.0°C; the photovoltaic module is limited to a temperature of 50.0°C; and the time limit is 1 minute.

[0030] Based on research and exploration, this invention also sets specific default flow rates of the cooling medium at system startup, real-time temperature monitoring intervals, safe temperature ranges for the inverter and photovoltaic modules, adjustment ranges for the circulating pump flow rate, and limit temperatures and time limits for the inverter and photovoltaic modules when the system malfunctions. By controlling specific process parameters, precise and reliable automatic control can be ensured, thereby achieving the objectives of this invention.

[0031] The present invention also provides an air source water heater, which includes a dual-temperature coordinated control system for the photovoltaic module and the inverter described in the present invention.

[0032] The inverter and photovoltaic module of this invention first undergo phase change heat exchange using phase change materials (PCMs) with different phase change temperatures, and then the PCMs are cooled by a cooling medium, which simultaneously absorbs and reuses the heat. The phase change temperature of the first PCM that exchanges heat with the inverter is 45±2℃, and the phase change temperature of the second PCM that exchanges heat with the photovoltaic module is 48±2℃. This differentiated design of the phase change temperatures of the first and second PCMs effectively maintains the inverter's operating temperature at approximately 45℃ and the photovoltaic module's operating temperature at approximately 48℃, achieving coordinated temperature control for both the photovoltaic and inverter devices. By using two different PCMs with varying phase change temperatures for heat exchange and cooling of the inverter and photovoltaic module respectively, the invention cleverly satisfies the unique requirements of independent temperature control settings for the photovoltaic module and the inverter, and their different operating temperature ranges. When the same cooling medium is used to exchange heat with the different PCMs of the two devices, precise control of the inverter and photovoltaic module to operate efficiently at different safe temperatures is achieved. Therefore, it effectively overcomes the shortcomings of existing technologies that cannot simultaneously meet the independent temperature control requirements of inverters and photovoltaic modules, solves the thermal interference problem caused by temperature conflicts between the two devices, and avoids mutual influence. This improves the conversion efficiency and stability of the photovoltaic modules. The power system obtains its power directly from the photovoltaic modules, eliminating the need for additional power sources. The system boasts high operating efficiency and low cost. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the composition of a photovoltaic power generation system;

[0034] Figure 2 This is a schematic diagram of a photovoltaic thermal system;

[0035] Figure 3 This is a schematic diagram of the dual-temperature coordinated control system for the photovoltaic module and inverter of the present invention;

[0036] Figure 4 This is a flowchart illustrating the dual-temperature coordinated control method for photovoltaic modules and inverters of the present invention.

[0037] Figure label:

[0038] 1-Photovoltaic module and heat dissipation module, 2-Pipeline, 3-Inverter and heat dissipation module, 4-Electrical equipment, 5-Heat exchanger, 6-Circulating pump, 7-Water pump, 8-Water tank. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the invention and do not constitute a limitation thereof.

[0040] like Figure 3 As shown, this invention provides an embodiment of a dual-temperature coordinated control system for a photovoltaic module and an inverter, comprising an inverter and heat dissipation module 3, a photovoltaic module and heat dissipation module 1, and an electrical device 4, all electrically connected. It also includes a pipe 2 that sequentially connects the inverter and heat dissipation module 3, the photovoltaic module and heat dissipation module 1, a heat exchanger 5, and a circulating pump 6; a water tank 8 and a water pump 7 are connected in a ring to the heat exchanger 5 via a water pipe. The cooling medium and water exchange heat in the heat exchanger 5, and the hot water returned to the water tank 8 after heat exchange is reused. Temperature sensors are respectively installed on the inverter heat dissipation module 3 and the photovoltaic module and heat dissipation module 1. The control monitor maintains an electrical connection with the temperature sensors, the circulating pump 6, the water pump 7, and the inverter and heat dissipation module 3 and the photovoltaic module and heat dissipation module 1.

[0041] In this embodiment, as Figure 3 As shown, the inverter and heat dissipation module 3 consists of an inverter and a first phase change material heat exchange structure, which is isolated from the inverter by a heat-conducting layer. The first phase change material heat exchange structure includes a first phase change material layer and a cooling medium channel disposed around the first phase change material layer. The photovoltaic module and heat dissipation module 1 consists of a photovoltaic module and a second phase change material heat exchange structure, which is isolated from the photovoltaic module by a heat-conducting layer. The second phase change material heat exchange structure includes a second phase change material layer and a cooling medium channel disposed around the second phase change material layer. The cooling medium disposed in the pipe 2, driven by the circulating pump 6, first exchanges heat with the first phase change material in the inverter and heat dissipation module 3 to raise its temperature, then exchanges heat with the second phase change material in the photovoltaic module and heat dissipation module 1 to raise its temperature, and then enters the heat exchanger 5 to exchange heat with the external circulating water to lower its temperature, thus circulating heat exchange in sequence. The controller monitors the operating temperature of the inverter and photovoltaic modules, and controls the flow rate of the cooling medium through the circulating pump 6, so that the inverter and photovoltaic modules operate at a safe temperature.

[0042] In this embodiment, the cooling medium is antifreeze, but water can also be used. The thermally conductive layer is made of thermally conductive silicone, but extruded polystyrene, polyurethane foam, or aerogel felt can also be used. The phase change material (PCM) can be selected according to application requirements (such as building insulation, electronic heat dissipation, clothing, etc.) and phase change temperature range. Common types include: commonly used, stable, and non-corrosive organic phase change materials, such as paraffin wax, fatty acids, and polyols; low-cost but potentially phase-separation or corrosive inorganic phase change materials, such as hydrated salts and molten salts; and composite phase change materials, such as paraffin / expanded graphite composites, which can improve the performance of single phase change materials and are often used for electronic heat dissipation. Composite phase change materials can be produced by determining the target temperature and mixing multiple phase change materials with similar phase change temperatures in a certain proportion to achieve the desired phase change temperature. For example, if a material needs to undergo a phase change at 25°C, it can be prepared by mixing paraffin C15 (approximately 30°C) with a small amount of a low-melting-point material (such as decane, melting point 17°C), thus lowering the target temperature of the mixture to 25°C. In typical engineering applications, the phase change temperature of phase change materials is usually controlled within ±2°C of the target temperature to avoid failure. The phase change material of this invention is a composite phase change material; the phase change temperature of the first phase change material is modulated to 45±2°C, and the phase change temperature of the second phase change material is modulated to 48±2°C.

[0043] By employing two phase change materials with different phase change temperatures for heat exchange and cooling of the inverter and photovoltaic modules respectively, this method cleverly meets the unique requirements that the temperature control of the photovoltaic modules and the inverter are independently set and that their operating temperature ranges are different. When the same cooling medium is used to exchange and cool the two devices with different phase change temperatures, the inverter and photovoltaic modules can be automatically and precisely controlled to operate efficiently at different safe temperatures. Therefore, it effectively overcomes the shortcomings of existing technologies that cannot simultaneously meet the independent temperature control requirements of the inverter and photovoltaic modules, solves the thermal interference problem of temperature conflict between the inverter and photovoltaic modules, avoids mutual influence, and thus improves the conversion efficiency and stability of the photovoltaic modules.

[0044] Please refer to Figure 4 The control method for the dual-temperature coordinated control system of photovoltaic modules and inverters provided by the present invention includes the following steps:

[0045] Step 1: With 50% of the rated flow rate as the default flow rate of the circulation pump, the system starts up, and the controller monitors the inverter temperature T_inv and the photovoltaic module temperature T_pvt in real time every 5 seconds via temperature sensors. Monitoring can be performed every 4-6 seconds as needed.

[0046] Please combine Figure 3Driven by the circulating pump 6, the antifreeze in pipe 2 first exchanges heat with the first phase change material in the inverter and heat dissipation module 3, raising its temperature. Specifically, the inverter generates heat during operation → this heat is conducted through thermally conductive silicone to the heat exchange structure of the first phase change material, where the heat absorption temperature rises to 45℃ → causing a solid-to-liquid phase change in the first phase change material → the antifreeze, cooled to 40℃ from the external heat exchanger 5, flows through the cooling medium channel surrounding the first phase change material (without contacting the inverter), absorbing the heat released by the liquid-to-solid phase change of the first phase change material → the antifreeze temperature rises to 45℃, while the first phase change material cools down to below 45℃. The antifreeze carries away heat, causing the inverter and heat dissipation module 3 to cool down, maintaining an operating temperature of approximately 45℃. The 45℃ antifreeze then enters the photovoltaic module and heat dissipation module 1 for heat exchange and absorption.

[0047] The waste heat generated during photovoltaic module power generation is conducted through thermally conductive silicone to the second phase change material heat exchange structure, where the second phase change material layer absorbs heat and its temperature rises to 48°C, causing a solid-liquid phase change. Antifreeze from the inverter and heat dissipation module 3 flows through the cooling medium channel outside the second phase change material to exchange heat with it (without contacting the photovoltaic module), absorbing the heat released by the second phase change material. The antifreeze temperature rises from 45°C to 48°C, while the second phase change material undergoes a liquid-solid phase change, releasing heat and cooling down to below 48°C. The antifreeze carries away heat, cooling the photovoltaic module and heat dissipation module 1, maintaining the operating temperature at approximately 48°C. The antifreeze, now at 48°C, flows out and enters the heat exchanger 5 to exchange heat with external circulating water, cooling down to 40°C, and then repeats the cycle.

[0048] like Figure 3 As shown, the antifreeze circulation path of the present invention is as follows: the antifreeze at 40°C in pipe 2 first flows through the first heat exchange structure in the inverter and heat dissipation module 3, causing the first phase change material therein to undergo a liquid-solid phase change and release heat, while the antifreeze absorbs heat and its temperature rises to 45°C → then flows through the second phase change material heat exchange structure in the photovoltaic module and temperature control module 1, causing the second phase change material therein to undergo a liquid-solid phase change and release heat, while the antifreeze absorbs heat again and its temperature rises to 48°C → the antifreeze enters the heat exchanger 5 and cools to 40°C → then circulates for heat exchange again.

[0049] Step 2: Based on the detected temperature, control the detector to determine whether the temperature of the inverter and the photovoltaic module are within their respective safe temperature ranges; and adjust the flow rate of the circulation pump with priority given to the inverter and photovoltaic module that exceed the safe temperature range by a relatively large amount.

[0050] The phase change state of the first phase change material can usually be determined based on the inverter temperature T_inv, and the phase change state of the second phase change material can be determined based on the photovoltaic module temperature T_pvt. That is, the phase change state of the phase change material can be indirectly determined by T_pvt / or T_inv. For example, when the inverter temperature T_inv≈45℃ is detected, it can be considered that the first phase change material is undergoing a phase change.

[0051] In this invention, the safe temperature range of the inverter is 44.5℃~45.5℃; the safe temperature range of the photovoltaic module is 47.5℃~48.5℃. Based on these safe temperature ranges, it is independently determined whether the inverter temperature T_inv and the photovoltaic module temperature T_pvt exceed the specified limits.

[0052] Inverter: If T_inv > 45.5℃ → overheating; if T_inv < 44.5℃ → undercooling;

[0053] Photovoltaic modules: If T_pvt > 48.5℃ → overheating; if T_pvt < 47.5℃ → undercooling.

[0054] When both the inverter temperature (T_inv) and the photovoltaic module temperature (T_pvt) exceed their respective upper limits of safe temperature range, the flow rate of the circulation pump is adjusted with priority given to the inverter or photovoltaic module that exceeds the safe temperature range by a relatively larger margin. For example, if T_inv = 47℃ and T_pvt = 49℃, meaning the inverter exceeds the upper limit of its safe temperature range by 1.5℃, while the photovoltaic module temperature only exceeds it by 0.5℃, then the antifreeze flow rate is increased with the inverter's over-limit temperature of 47℃ as the target, resulting in a decrease in both the inverter and photovoltaic module temperatures.

[0055] Basic methods for adjusting the antifreeze flow rate of circulation pump 6:

[0056] Increase flow rate: Increase the flow rate of circulation pump 6 by 10%, which is 10% of the default flow rate → This can simultaneously enhance the heat dissipation of photovoltaic modules and inverters; Decrease flow rate: Decrease the flow rate of circulation pump 6 by 10%, which is 10% of the default flow rate → This can simultaneously weaken the heat dissipation of photovoltaic modules and inverters.

[0057] If the temperature of the inverter and the temperature of the photovoltaic module are both within their respective safe temperature ranges, the flow rate of the circulating pump 6 will remain constant.

[0058] Step 3: After increasing the flow rate, and after two consecutive tests confirming that the inverter temperature T_inv and the photovoltaic module temperature T_pvt are both within their respective safe temperature ranges, reduce the flow rate of the circulation pump 6. That is, the adjustment range can be reduced from the original 10% increase to 5%.

[0059] If the flow rate is increased and the temperature of the inverter and / or the photovoltaic module is detected to be higher than the upper limit of the safe temperature range twice in a row, it will be treated as an abnormal state.

[0060] Step 4: When the inverter temperature exceeds the limit of 48.0℃ or / and the photovoltaic module temperature exceeds the limit of 50.0℃, and this condition persists for a limit of 1 minute, handle the abnormal state as described above. That is, adjust the circulation pump 6 to its maximum flow rate, reduce the photovoltaic module's power generation to 70% of its rated power, and trigger an alarm for "heat dissipation overload".

[0061] The control method of this invention can be precisely matched with the dual-temperature coordinated control system for photovoltaic modules and inverters proposed in this invention. By automatically and in real-time monitoring the operating temperatures of the photovoltaic modules and inverters through a control monitor, and adjusting the flow rate of the circulating pump to ensure timely heat exchange and cooling of both, the system operates within its respective safe temperature range. This avoids thermal interference problems caused by temperature conflicts between the inverter and photovoltaic modules, thereby improving the conversion efficiency and stability of the photovoltaic modules. Furthermore, an abnormal state handling and alarm mechanism is included to ensure the safe and reliable operation of the system.

[0062] The present invention also provides an air source water heater, which includes a dual-temperature coordinated control system for the photovoltaic module and the inverter described in the present invention.

[0063] It should be noted that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the invention. Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the technical features and steps set forth in these embodiments do not limit the scope of protection of this invention.

[0064] Techniques, methods, and apparatus known to those skilled in the art are not discussed in detail herein, but where appropriate, such techniques, methods, and apparatus should be considered part of this specification. Any specific values ​​in this specification should be interpreted as merely exemplary and not as limiting the invention.

[0065] For ease of description, the terms used in this specification to describe position, such as "above," "to the left," and "in front," are only used to describe the spatial relationship between a component and other components in the embodiments shown in the figures. The relative position will change when the component is placed in different locations; therefore, the positional relationships in the embodiments shown in the figures should not be construed as limiting the present invention. Furthermore, it should be noted that the use of terms such as "first" and "second" in this specification is merely for distinguishing similar components and does not imply a sequential order; therefore, it should not be construed as limiting the scope of protection of this invention.

[0066] The above description is merely a specific embodiment of the present invention. It should be noted that any modifications, equivalent substitutions, and variations made within the spirit and framework of the present invention should be included within the protection scope of the present invention.

Claims

1. A dual-temperature coordinated control system for photovoltaic modules and inverters, characterized in that, The device includes an inverter and a heat dissipation module consisting of an inverter and a first phase change material heat exchange structure, a photovoltaic module and a heat dissipation module consisting of a photovoltaic module and a second phase change material heat exchange structure, and a control monitor. The cooling medium first flows through the first phase change material heat exchange structure for heat exchange, then flows through the second phase change material heat exchange structure for heat exchange, and then enters the heat exchanger for heat exchange and cooling, and circulates for heat exchange. The control monitor monitors the operating temperature of the inverter and the photovoltaic module and controls the flow rate of the cooling medium so that the inverter and the photovoltaic module operate at a safe temperature.

2. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 1, characterized in that, It also includes a circulating pump located between the inverter, the heat dissipation module, and the heat exchanger; temperature sensors located on the inverter and the photovoltaic module respectively; the cooling working fluid exchanging heat with external circulating water in the heat exchanger for cooling; and the control monitor being electrically connected to the temperature sensors and the circulating pump.

3. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 1, characterized in that, The first phase change material heat exchange structure is isolated from the inverter through a heat-conducting layer; the second phase change material heat exchange structure is isolated from the photovoltaic module through a heat-conducting layer.

4. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 1, characterized in that, The first phase change material heat exchange structure includes a first phase change material and a cooling working medium channel disposed around the first phase change material; the second phase change material heat exchange structure includes a second phase change material and a cooling working medium channel disposed around the second phase change material.

5. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 4, characterized in that, The phase change material used is one of organic phase change materials, inorganic phase change materials, or composite phase change materials.

6. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 5, characterized in that, The phase change material is a composite phase change material; the phase change temperature of the first phase change material is 45±2 ℃, and the phase change temperature of the second phase change material is 48±2 ℃.

7. The dual-temperature coordinated control system for photovoltaic modules and inverters as described in claim 3, characterized in that, The thermally conductive layer is prepared from one of thermally conductive silicone, extruded polystyrene, polyurethane foam, or aerogel felt.

8. A control method for a dual-temperature coordinated control system for a photovoltaic module and an inverter as described in any one of claims 1 to 7, comprising the following control steps: Step 1: Set the default flow rate of the circulation pump, start the system, and monitor the temperature of the inverter and the photovoltaic module at predetermined intervals; Step 2: Determine whether the temperature of the inverter and the photovoltaic module are within their respective safe temperature ranges; and prioritize the inverter and photovoltaic module that are more likely to exceed their safe temperature ranges by adjusting the flow rate of the circulation pump; if the temperature of the inverter and the photovoltaic module are both within their respective safe temperature ranges, maintain the current flow rate of the circulation pump. Step 3: When the flow rate is increased, and the temperature of the inverter and the photovoltaic module are both within the safe temperature range for two consecutive tests, reduce the adjustment range of the circulation pump flow rate; when the flow rate is increased, and the temperature of the inverter and / or the photovoltaic module is higher than the upper limit of their respective safe temperature range for two consecutive tests, treat it as an abnormal state. Step 4: When the temperature of the inverter and / or the temperature of the photovoltaic module are higher than their respective limit temperatures for a limited time, the abnormal state is handled as described above. The circulation pump is adjusted to the maximum flow rate, the power generation of the photovoltaic module is reduced to 70% of the rated power, and an alarm for "heat dissipation overload" is triggered.

9. The control method as described in claim 8, characterized in that, The default flow rate is 50% of the rated flow rate; the scheduled time is 4-6 seconds.

10. The control method as described in claim 8, characterized in that, The inverter has a safe temperature range of 44.5℃ to 45.5℃; the photovoltaic module has a safe temperature range of 47.5℃ to 48.5℃.

11. The control method as described in claim 8, characterized in that, The flow rate of the circulating pump is adjusted to 5% to 10% of the rated flow rate.

12. The control method as described in claim 8, characterized in that, The inverter is limited to a temperature of 48.0°C; the photovoltaic module is limited to a temperature of 50.0°C; and the time limit is 1 minute.

13. An air source heat pump water heater, characterized in that, Includes a dual-temperature coordinated control system for photovoltaic modules and inverters as described in any one of claims 1 to 7.

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