Micro-channel controllable phase change cooling back plate under micro-positive pressure and cooling method

Abstract

The invention discloses a micro-channel controllable phase change cooling back plate under micro-positive pressure and discloses a cooling method, the micro-channel controllable phase change cooling back plate comprises a plurality of cooling plate bodies arranged in parallel, each cooling plate body is provided with a micro-channel, an inlet of each micro-channel is provided with an expansion valve, the cooling plate bodies are used for making contact with heating devices, and the cooling plate bodies correspond to the heating devices one to one; the cooling plate bodies, the microcontroller units and the first temperature sensors are arranged in a one-to-one correspondence mode, the first temperature sensors and the expansion valves are electrically connected with the microcontroller units, the first temperature sensors are used for collecting the real-time temperature of a heating device, and the first temperature sensors are used for collecting the real-time temperature of the heating device. The microcontroller unit is configured to receive a temperature signal fed back by the first temperature sensor, control the opening degree of the expansion valve and enable the opening degree of the expansion valve to be in positive correlation with the real-time temperature. And the flows of refrigerants introduced into the cooling plate bodies corresponding to the heating devices with different temperatures are different, so that each heating device is accurately cooled, and the energy consumption is reduced.

Description

Technical Field

[0001] This invention relates to the field of server heat dissipation technology, and in particular to a microchannel controllable phase change cooling backplate and cooling method under micro-positive pressure. Background Technology

[0002] With the development of cloud computing, big data, and artificial intelligence (AI), the computing density of servers supporting cloud computing, big data, and AI in data centers is growing exponentially. The power consumption and heat generation of various chips (CPU, GPU, NPU, etc.) in servers are also increasing dramatically, leading to a sharp increase in energy consumption for cooling these heat-generating components. Moreover, the heat generation of each heat-generating component is different, requiring different cooling efficiencies and power. Current air-cooling and liquid-cooling systems cannot dissipate heat from these components in a timely manner, resulting in energy waste and further increasing the energy consumption of the cooling system. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a microchannel controllable phase change cooling backplate and cooling method under micro-positive pressure, which can accurately and timely cool multiple heat-generating devices and reduce energy consumption.

[0004] According to a first aspect of the present invention, a microchannel controllable phase change cooling backplate under micro-positive pressure includes: a plurality of cooling plates arranged in parallel, each cooling plate having a microchannel, an expansion valve at the inlet of the microchannel, through which cooled refrigerant flows, the cooling plates being used to contact a heating device to transfer heat, and the cooling plates and the heating devices corresponding one-to-one; a plurality of microcontroller units and a plurality of first temperature sensors, the cooling plates, the microcontroller units, and the first temperature sensors being arranged one-to-one, the first temperature sensors and the expansion valves being electrically connected to the microcontroller units, the first temperature sensors being used to acquire the real-time temperature T of the heating device, and the microcontroller units being configured to receive the temperature signal fed back from the first temperature sensors and control the opening degree of the expansion valves, and to make the opening degree of the expansion valves positively correlated with the real-time temperature T.

[0005] At least the following beneficial effects are achieved: the higher the temperature of the heating element reported by the first temperature sensor, the larger the opening of the expansion valve adjusted by the microcontroller unit, resulting in a larger flow rate of refrigerant entering the microchannel and more efficient cooling of the heating element. Conversely, the lower the temperature of the heating element reported by the first temperature sensor, the smaller the opening of the expansion valve adjusted by the microcontroller unit, resulting in a smaller flow rate of refrigerant entering the microchannel and ensuring that the heating element is at its optimal operating temperature. Different heating elements, and heating elements operating under different conditions, generate different amounts of heat and have different temperatures. The flow rate of refrigerant entering the cooling plate of the microchannel controllable phase change cooling backplane under micro-positive pressure varies for each heating element, enabling precise cooling of each heating element. This significantly reduces the failure rate of heating elements, extends the lifespan of the heating elements and the entire server, and reduces the energy consumption of the cooling backplane, thus saving energy.

[0006] According to some embodiments of the present invention, a heat insulation layer is connected to one side of the cooling plate, and the microcontroller unit is disposed on the side of the heat insulation layer away from the cooling plate.

[0007] According to some embodiments of the present invention, a heat-conducting layer is provided between the cooling plate and the heating device, the heat-conducting layer being used to conduct the heat from the heating device to the cooling plate.

[0008] According to some embodiments of the present invention, the thermally conductive layer may be a liquid metal layer.

[0009] According to some embodiments of the present invention, the inlet of the microchannel is provided with a filter assembly, and the filter assembly and the corresponding expansion valve are arranged sequentially along the flow direction of the refrigerant.

[0010] According to some embodiments of the present invention, the inlet of the microchannel is provided with an inlet shut-off valve, the inlet shut-off valve, the filter assembly and the expansion valve are arranged along the flow direction of the refrigerant, and the outlet of the microchannel is provided with an outlet shut-off valve.

[0011] According to some embodiments of the present invention, the outlet of the microchannel is provided with an outlet pressure sensor, which is used to detect the pressure of the refrigerant at the outlet of the microchannel.

[0012] According to some embodiments of the present invention, the inlet of the microchannel is provided with an inlet pressure sensor, which is used to detect the pressure of the refrigerant at the inlet of the microchannel.

[0013] According to a second aspect of the present invention, a cooling method applied to the above-described microchannel controllable phase change cooling backplate under micro-positive pressure includes the following steps: The microchannel controllable phase change cooling backplate under micro-positive pressure includes multiple cooling plates, each of which has a microchannel. The inlet of each microchannel is equipped with an expansion valve, through which cooled refrigerant flows. The cooling plates are used to contact the heating devices to transfer heat. Each cooling plate corresponds to a heating device. The flow rate of the refrigerant in the microchannel can be controlled by adjusting the opening of the expansion valve. The refrigerant is used to cool the heating devices. The cooled refrigerant is introduced into the expansion valve. After flowing through the expansion valve, the cooled refrigerant changes from a liquid phase to a gas phase. The gas phase refrigerant then flows through the microchannel. The power consumption of each heating element is collected. When the relative power change rate of the heating element ΔP% / Δt ≥ 10% / s or ΔP% / Δt ≤ -10% / s, feedforward compensation is performed to adjust the opening of the expansion valve to counteract the temperature fluctuation caused by the sudden change in power of the heating element. The initial power is P0, and the power becomes P1 after time Δt. ΔP% = (P1 - P0) / P0 × 100%. The real-time temperature T of each heating element is collected to obtain the temperature change rate ΔT / Δt of each heating element. The opening of the expansion valve is adjusted by the real-time temperature T and the temperature change rate ΔT / Δt. The initial temperature is T1, and the temperature after time Δt is T2, where ΔT = T2 - T1. When T < Tmin, Tmin is the lower limit of the optimal operating temperature of the heating device, and the opening of the expansion valve is reduced to the minimum threshold. When Tmin≤T≤Tmax, and -0.5℃ / s≤ΔT / Δt≤0.5℃ / s, Tmax is the upper limit of the optimal operating temperature of the heating device, and the expansion valve is maintained at the current opening. When T > Tmax or ΔT / Δt > 0.5℃ / s, increase the opening of the expansion valve.

[0014] It has at least the following beneficial effects: This cooling method collects the power consumption of each of the heat-generating devices, adjusts the opening of the expansion valve in advance according to the power change of the heat-generating devices, adjusts the refrigerant flow of the microchannel in advance, adjusts the cooling effect of the cooling plate, adjusts the heat-generating devices to the optimal working temperature, ensures the working efficiency and life of the heat-generating devices, and can also reduce the energy consumption of the cooling back plate.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the structure of the cooling plate, expansion valve, microcontroller unit, and first temperature sensor according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an embodiment of the present invention; Icon labels: Heating element 10; Cooling plate 100, microchannel 110, outlet pressure sensor 111, inlet pressure sensor 112, filter assembly 113, inlet shut-off valve 114, outlet shut-off valve 115, heat insulation layer 120, heat conduction layer 130; Expansion valve 200; Microcontroller Unit 300; First temperature sensor 400; Compressor 500; Condenser 600; Liquid storage container 700; 800 server racks. Detailed Implementation

[0017] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0018] In the description of this invention, the use of "first" and "second" is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0019] In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0020] As mentioned above, the heat generated by the heat-generating components in the server rack varies, and the heat generated by the same heat-generating component will also vary under different operating conditions. Therefore, the cooling requirements of different heat-generating components are also different. Applying the same cooling to all heat-generating components will result in insufficient cooling capacity and wasted energy, further increasing the energy consumption of the cooling system.

[0021] Reference Figure 1 and Figure 2This invention discloses a microchannel controllable phase change cooling backplate under micro-positive pressure, comprising multiple cooling plates 100 arranged in parallel, multiple first temperature sensors 400, and multiple microcontroller units 300. Each cooling plate 100 is provided with a microchannel 110, and an expansion valve 200 is provided at the inlet of the microchannel 110. The expansion valve 200 and the microchannel 110 allow cooled refrigerant to flow through. The cooling plate 100 is used to contact a heating element 10 to transfer heat, and the cooling plate 100 and the heating element 10 correspond one-to-one. The cooling plate 100, the first temperature sensor 400, and the microcontroller unit 300 are connected in parallel. A one-to-one configuration is established, that is, a cooling plate 100, an expansion valve 200, a first temperature sensor 400 and a microcontroller unit 300 form a cooling group. Within a cooling group, a microcontroller unit 300 is electrically connected to a first temperature sensor 400 and an expansion valve 200. The first temperature sensor 400 is used to collect the real-time temperature T of the heating device 10. The microcontroller unit 300 is configured to receive the temperature signal fed back from the first temperature sensor 400 and control the opening degree of the expansion valve 200, and make the opening degree of the expansion valve 200 positively correlated with the real-time temperature T.

[0022] It is understandable that the heating element 10 has an optimal operating temperature. The heating element 10 operates most efficiently when at its optimal operating temperature, which reduces its failure rate and helps ensure its lifespan. The lower limit of the optimal operating temperature is Tmin, and the upper limit is Tmax. Different types of heating elements 10 have different Tmin and Tmax values, which can be obtained based on the specific heating element 10.

[0023] When the heating element 10 operates, it generates heat, which is then transferred to the cooling plate 100 and the first temperature sensor 400. The first temperature sensor 400 detects the real-time temperature T of the heating element 10 and feeds this temperature signal back to the microcontroller unit 300. The microcontroller unit 300 controls the opening of the expansion valve 200 based on the relationship between the real-time temperature T and the optimal operating temperature, ensuring that the opening of the expansion valve 200 is positively correlated with the real-time temperature T. Generally speaking, the higher the real-time temperature T, the larger the opening of the expansion valve 200. Expansion valve 200 provides cooled refrigerant, which enters microchannel 110 after passing through expansion valve 200. The refrigerant in microchannel 110 can absorb the heat from cooling plate 100. After absorbing heat, the refrigerant is discharged from microchannel 110. By continuously repeating the above process, the heating device 10 can be cooled. The opening degree of expansion valve 200 limits the flow rate of refrigerant entering microchannel 110. The greater the flow rate of refrigerant entering microchannel 110, the better the cooling effect of cooling plate 100 on heating device 10, and the faster the heating device 10 can cool down. The higher the temperature of the heating element 10 reported by the first temperature sensor 400, the larger the opening of the expansion valve 200 is adjusted by the microcontroller unit 300, resulting in a larger flow rate of refrigerant entering the microchannel 110 and more efficient cooling of the heating element 10. Conversely, the lower the temperature of the heating element 10 reported by the first temperature sensor 400, the smaller the opening of the expansion valve 200 is adjusted by the microcontroller unit 300, resulting in a smaller flow rate of refrigerant entering the microchannel 110 and ensuring that the heating element 10 is at its optimal operating temperature.

[0024] Different heat-generating devices 10 and different operating conditions result in different heat generation and temperatures. The flow rate of refrigerant introduced into the cooling plate 100 of the microchannel controllable phase change cooling backplane corresponding to the heat-generating device 10 is different, so as to achieve precise cooling for each heat-generating device 10. This can significantly reduce the failure rate of the heat-generating device 10, extend the service life of the heat-generating device 10 and the entire server, and reduce the energy consumption of the cooling backplane, thus saving energy.

[0025] Different regions of the microchannels 110 are distributed in different regions of the cooling plate 100, which helps to make the cooling effect more uniform in different regions of the cooling plate 100, avoids weak cooling areas in the cooling plate 100, and thus avoids weak cooling areas and unbalanced cooling in the heat-generating device 10. The diameter of the microchannels 110 can be 0.5-1mm.

[0026] This embodiment can use R134a, R410A, or other environmentally friendly phase change refrigerants. Through reasonable system pressure design, the refrigerant can boil within the required temperature range of -10℃ to 10℃ or higher (e.g., 30℃ to 50℃), thereby efficiently cooling the heating element 10. Different types or models of heating elements 10 have different optimal operating temperatures, which are not limited here. The microcontroller unit 300 is also called an MCU.

[0027] When the microchannel controllable phase change cooling backplate operates under micro-positive pressure, the power consumption of each heating device 10 can be collected. When the relative power change rate of the heating device 10 ΔP% / Δt ≥ 10% / s or ΔP% / Δt ≤ -10% / s, feedforward compensation is performed to adjust the opening of the expansion valve 200 to offset the temperature fluctuation caused by the power change of the heating device 10. The initial power is P0, and after time Δt, the power becomes P1, where ΔP% = (P1 - P0) / P0 × 100%. The real-time temperature T of each heating element 10 is collected to obtain the temperature change rate ΔT / Δt of each heating element 10. The opening of the expansion valve 200 is adjusted by the real-time temperature T and the temperature change rate ΔT / Δt. The initial temperature is T1, and the temperature after time Δt is T2, where ΔT = T2 - T1. When T < Tmin, Tmin is the lower limit of the optimal operating temperature of the heating device 10, and the opening of the expansion valve 200 is reduced to the minimum threshold. When Tmin≤T≤Tmax, and -0.5℃ / s≤ΔT / Δt≤0.5℃ / s, Tmax is the upper limit of the optimal operating temperature of the heating device 10, and the expansion valve 200 is maintained at the current opening. When T > Tmax or ΔT / Δt > 0.5℃ / s, increase the opening of expansion valve 200.

[0028] Understandably, Δt is 0.1-1s. The minimum threshold for the opening of expansion valve 200 is 5%-10%. The power of heating device 10 is obtained by collecting the current and voltage of heating device 10; the power is equal to the product of current and voltage. Cooled refrigerant is supplied to expansion valve 200, and the opening of expansion valve 200 is controlled according to the refrigerant superheat. The target refrigerant superheat is set to 5-7℃, and the refrigerant superheat is the difference between the temperature of the refrigerant at the outlet of microchannel 110 and the refrigerant saturation temperature.

[0029] The opening of the feedforward compensation adjustment expansion valve 200 can adjust the refrigerant flow of the microchannel 110 in advance, so that the cooling plate 100 can cool the heating device 10 more quickly, adjust the heating device 10 to the optimal working temperature, ensure the working efficiency and service life of the heating device 10, and accurately cool each heating device 10 in time, while also reducing the energy consumption of the cooling backplate.

[0030] Let the initial power be P0. After time Δt, the power becomes P1. ΔP% = (P1 - P0) / P0 × 100%. When the relative power change rate ΔP% / Δt is positive, it indicates that the power of the heating device 10 is increasing. When the relative power change rate ΔP% / Δt is negative, it indicates that the power of the heating device 10 is decreasing.

[0031] When ΔT / Δt is positive, it indicates that the heating device 10 is heating up; when ΔT / Δt is negative, it indicates that the heating device 10 is cooling down. Specifically, ΔT = T2 - T1, Δt = t2 - t1, t1 and T1 represent the initial time and temperature values ​​per unit time, respectively, and t2 and T2 represent the final time and temperature values ​​per unit time, respectively.

[0032] It is known that when the microchannel controllable phase change cooling backplane operates under micro-positive pressure, the refrigerant passes through the microchannel 110. If the temperature of the cooling plate 100 is too low, condensation will easily form on the surface of the cooling plate 100. This condensation will penetrate into various areas of the server, causing short circuits, accelerating the oxidation and corrosion of the cooling plate 100 and other server components, and reducing the thermal conductivity of the cooling plate 100 and other server components. This is especially true when the cooling plate 100 is made of copper, as the condensation will further accelerate its oxidation and corrosion.

[0033] When the microchannel controllable phase change cooling backplate is working under micro-positive pressure, it provides cooled refrigerant to the expansion valve 200. The opening degree of the corresponding expansion valve 200 is controlled according to the refrigerant superheat. The target refrigerant superheat is set to 5-7℃. The refrigerant superheat is the difference between the temperature of the refrigerant at the outlet of the microchannel 110 and the refrigerant saturation temperature.

[0034] In some of these embodiments, reference is made to Figure 2A cooling backplate is applied to a sealable server rack 800. The server rack 800 houses multiple heat-generating devices 10 and multiple cooling plates 100. The server rack 800 is filled with dry compressed air, and the pressure inside the server rack 800 is maintained at 0.1-1 kPa. The required heat-generating devices 10 are installed inside the server rack 800, with each heat-generating device 10 corresponding to a cooling plate 100. The heat-generating devices 10 press against the cooling plates 100. The server rack 800 is filled with dry compressed air, maintaining the pressure inside the server rack 800 at 0.1-1 kPa, thereby reducing the heat generated inside the server rack 800. Device 10, cooling plate 100, and other components operate in a dry environment with a pressure of 0.1-1 kPa. Under these conditions, the temperature of cooling plate 100 can be lowered without a significant risk of condensation on cooling plate 100, heat-generating device 10, and other components. This means that a coolant with a lower boiling point can be used for the cooling backplate, allowing for a lower temperature of the coolant entering the microchannel 110. This improves the cooling effect of cooling plate 100 while preventing condensation from damaging cooling plate 100, heat-generating device 10, and other server components, thus enhancing the cooling effect of cooling plate 100 on heat-generating device 10 and the entire server. The server rack 800 is maintained in a slightly positive pressure environment (0.1-1 kPa) to prevent condensation, ensuring that cooling plate 100, heat-generating device 10, and other components do not condense.

[0035] Specifically, the environment inside server rack 800 meets the ISO 8573.1.class-1.1.1 standard.

[0036] A compressed gas dryer can be used to provide dry compressed air to the server rack 800 and adjust the air pressure inside the server rack 800. The server rack 800 is equipped with an air inlet and an air outlet. The air inlet is used to connect to the compressed gas dryer. The air inlet and air outlet are equipped with an air inlet valve and an air outlet valve, respectively. When the air inlet valve is opened, the inner cavity of the server rack 800 can be connected to dry compressed air through the air inlet. When the air outlet valve is opened, the original air and the connected dry compressed air inside the server rack 800 can be discharged through the air outlet. At the same time, closing the air inlet valve and the air outlet valve can maintain the sealing of the server rack 800 and the stability of the air pressure inside the server rack 800.

[0037] Server rack 800 is equipped with a dew point meter to detect the dew point parameters and humidity inside the rack. Before the servers inside server rack 800 are powered on and before refrigerant enters the cooling plates 100, the humidity inside server rack 800 is measured using the dew point meter. If the humidity is higher than the standard value (which will cause condensation on the cooling plates 100), the inlet and outlet valves are opened to quickly fill server rack 800 with dry compressed air, expelling the existing air. Once the humidity inside server rack 800 reaches the standard value, the inlet and outlet valves are closed, stopping the supply of dry compressed air. The servers can then be powered on. During server operation, if the humidity again exceeds the standard value, the inlet and outlet valves can be opened again to supply fresh dry compressed air to the server rack 800 to bring the humidity back to the standard value. If the humidity exceeds the specified range, a humidity alarm will be issued. By dynamically adjusting the dew point and flow rate of the dry compressed air supplied to the server rack 800, the dew point temperature of the air at any location within the server rack 800 is ensured to always be lower than the lowest possible surface temperature at that location, and a stable micro-positive pressure environment (air pressure between 0.1 and 1 kPa) is provided for this purpose, meaning that the server rack 800 has a dew point replenishment function.

[0038] The server rack 800 is also equipped with a thermometer or a second temperature sensor. The thermometer or the second temperature sensor is used to detect the overall temperature inside the server rack 800. When the thermometer or the second temperature sensor detects that the temperature inside the server rack 800 is too high, the temperature inside the server rack 800 can be cooled by opening the air inlet valve and the air outlet valve to replace the air inside the server rack 800.

[0039] The server rack 800 can be sealed under positive and negative pressure dew point -40℃, and no condensation will occur on the cooling plate 100, heat-generating device 10 and other devices inside the server rack 800.

[0040] In some of these embodiments, reference is made to Figure 2The microchannel controllable phase change cooling backplate under micro-positive pressure is applied to the circulation loop, which includes a compressor 500, a condenser 600, and a liquid storage container 700. The compressor 500, condenser 600, liquid storage container 700, expansion valve 200 at the inlet of microchannel 110, and microchannel 110 are connected in sequence through pipes to form a circulation loop. Multiple microchannels 110 are arranged in parallel. The circulation loop is used to circulate refrigerant. In the manufacturing process of the microchannel controllable phase change cooling backplate under micro-positive pressure, the connection of the circulation loop is first completed, then the circulation loop is evacuated to a vacuum degree ≤10Pa, and finally the refrigerant is cooled to a set temperature (such as 15℃-20℃). Then the cooled refrigerant is injected into the circulation loop. When the microchannel controllable phase change cooling backplate operates under micro-positive pressure, driven by the compressor 500, the refrigerant has a high pressure and is in the liquid phase when it passes through the condenser 600. The refrigerant dissipates its heat into the air through the condenser 600. Then, after passing through the expansion valve 200, the refrigerant enters the microchannel 110. After entering the microchannel 110, the refrigerant has a lower pressure and returns to the gas phase. The refrigerant absorbs heat, thus absorbing the heat of the heating element 10 through the cooling plate 100, which means that the cooling plate 100 cools the heating element 10. Then, the gaseous refrigerant returns to the compressor 500, which drives the refrigerant again and pressurizes it to a higher pressure. The liquid storage container 700 acts as a buffer for the refrigerant.

[0041] Evacuate the circulation loop to a vacuum level of ≤10Pa to minimize the amount of gas in all microchannels 110 and the entire circulation loop, thereby preventing residual gas in the microchannels 110 and the entire circulation loop from affecting the refrigerant phase change efficiency and heat exchange effect.

[0042] Understandably, the greater the power and energy consumption of the compressor 500 and condenser 600, the greater the cooling capacity of the microchannel controllable phase change cooling backplate under micro-positive pressure, which is beneficial to improving the cooling effect on the heat-generating device 10. Since the cooling plate 100 can accurately cool each heat-generating device 10, the compressor 500 and condenser 600 can work at an appropriate power and energy consumption level, avoiding unnecessary work by the compressor 500 and condenser 600.

[0043] In some embodiments, a heat insulation layer 120 is connected to one side of the cooling plate 100, and the microcontroller unit 300 is disposed on the side of the heat insulation layer 120 away from the cooling plate 100. The heat insulation layer 120 can form a thermal insulation between the cooling plate 100 and the microcontroller unit 300, so as to prevent the cooling plate 100 from affecting the normal operation of the microcontroller unit 300.

[0044] Understandably, the heat insulation layer 120 is attached to one side of the cooling plate 100, the microcontroller unit 300 is attached to the heat insulation layer 120, and the first temperature sensor 400 and the expansion valve 200 are also located on the cooling plate 100. This allows the cooling plate 100, the heat insulation layer 120, the microcontroller unit 300, the first temperature sensor 400, and the expansion valve 200 to form a module. This facilitates the wiring between the microcontroller unit 300 and the first temperature sensor 400, as well as between the microcontroller unit 300 and the expansion valve 200. Each module works independently, making it easy to install and maintain individual modules.

[0045] In some embodiments, a heat-conducting layer 130 is provided between the cooling plate 100 and the heating device 10. The heat-conducting layer 130 is used to conduct the heat of the heating device 10 to the cooling plate 100. The heat-conducting layer 130 enables the heat of each area of ​​the heating device 10 to be transferred to each area of ​​the cooling plate 100 more quickly, thereby improving the heat conduction effect between the cooling plate 100 and the heating device 10.

[0046] The thermally conductive layer 130 can be a liquid metal layer or a coating made of other materials with high thermal conductivity. Liquid metal layers typically refer to coating materials with low-melting-point metal alloys, such as gallium-based alloys, as the main component. They possess high thermal conductivity, fluidity, and special physicochemical properties, and are widely used in electronic heat dissipation, industrial corrosion protection, and high-end decorative applications. The thermally conductive layer 130 can also be a thermally conductive silicone grease layer.

[0047] In some embodiments, the inlet of the microchannel 110 is provided with a filter assembly 113. The filter assembly 113 and the corresponding expansion valve 200 are arranged sequentially along the flow direction of the refrigerant. The refrigerant needs to pass through the filter assembly 113 before entering the expansion valve 200. The filter assembly 113 plays the role of filtering out impurities in the refrigerant, so as to prevent the expansion valve 200 and the microchannel 110 from being blocked by impurities in the refrigerant.

[0048] In this embodiment, the filtration accuracy of the filter component 113 is ≤5μm.

[0049] In some embodiments, the microchannel 110 is provided with an inlet shut-off valve 114 at its inlet. The inlet shut-off valve 114, the filter assembly 113, and the expansion valve 200 are arranged along the refrigerant flow direction. The microchannel 110 is provided with an outlet shut-off valve 115 at its outlet. The inlet shut-off valve 114 is used to open or close the inlet of the microchannel 110. When both the inlet shut-off valve 114 and the outlet shut-off valve 115 are opened, the refrigerant can pass through the inlet of the microchannel 110, the filter assembly 113, the expansion valve 200, and the microchannel 110 in sequence. When the inlet shut-off valve 114 is closed, the inlet of the microchannel 110 is closed. When both the inlet shut-off valve 114 and the outlet shut-off valve 115 are closed, all refrigerant and other substances cannot enter the filter assembly 113, the expansion valve 200, and the microchannel 110. After the cooling plate 100 is processed and the inlet shut-off valve 114, filter assembly 113, expansion valve 200, and outlet shut-off valve 115 are installed, protective gas can be injected into the microchannel 110. Then, the inlet shut-off valve 114 and outlet shut-off valve 115 are simultaneously closed, so that the protective gas is sealed within the expansion valve 200 and the microchannel 110. The protective gas protects the expansion valve 200 and the microchannel 110, slowing down their oxidation. The protective gas can be helium.

[0050] In some embodiments, the outlet of the microchannel 110 is equipped with an outlet pressure sensor 111. The outlet pressure sensor 111 is used to detect the pressure of the refrigerant at the outlet of the microchannel 110. By detecting the pressure of the refrigerant at the outlet of the microchannel 110, the refrigerant saturation temperature can be obtained. For example, the refrigerant saturation temperature can be found by looking up a refrigerant saturation temperature-pressure gauge.

[0051] Of course, a third temperature sensor can be installed at the outlet of the microchannel 110 to detect the temperature of the refrigerant at the outlet of the microchannel 110.

[0052] In some embodiments, the inlet of the microchannel 110 is provided with an inlet pressure sensor 112, which is used to detect the pressure of the refrigerant at the inlet of the microchannel 110. The value of the inlet pressure sensor 112 can be used to determine whether there is enough refrigerant flowing to the inlet of the microchannel 110, and the difference between the inlet pressure sensor 112 and the outlet pressure sensor 111 can be used to determine the blockage of the microchannel 110.

[0053] It is understood that both the outlet pressure sensor 111 and the inlet pressure sensor 112 are electrically connected to the microcontroller unit 300. The outlet pressure sensor 111 feeds back the pressure signal of the refrigerant at the outlet of the microchannel 110 to the microcontroller unit 300, and the inlet pressure sensor 112 feeds back the pressure signal of the refrigerant at the inlet of the microchannel 110 to the microcontroller unit 300.

[0054] When the microchannel controllable phase change cooling backplate is working under micro-positive pressure, it collects the power signal of the heating device 10. The microcontroller unit 300 adjusts the opening of the expansion valve 200 according to the power change of the heating device 10. When the power of the heating device 10 increases, the heat generated by the heating device 10 increases. At this time, the opening of the expansion valve 200 can be increased in advance.

[0055] The microcontroller unit 300 receives the real-time temperature T signal of the heating device 10 collected by the first temperature sensor 400, and also receives the pressure signal of the refrigerant at the outlet of the microchannel 110 detected by the outlet pressure sensor 111, and controls the opening of the expansion valve 200 with the target refrigerant superheat of 5-7℃.

[0056] It is known that when the load of the heating device 10 increases from 50% to 100%, the heat flux density increases sharply. If the refrigerant flow rate of the corresponding cooling plate 100 does not increase synchronously, the refrigerant in the microchannel 110 will change from "partial phase change" to "full phase change", causing vapor to occupy the entire microchannel 110, forming "air blockage" and causing heat dissipation interruption. Conversely, when the load drops sharply, the refrigerant that has not undergone phase change will accumulate in the microchannel 110, increasing the flow resistance of the refrigerant, and the consumption of the compressor 500 will increase by 20% to 25%.

[0057] The microchannel controllable phase change cooling backplate under micro-positive pressure also includes a host computer. The host computer can detect the power of multiple heating devices 10. Multiple microcontroller units 300 are electrically connected to the host computer. The host computer detects the power of multiple heating devices 10 and sends the power signal of the heating devices 10 to the microcontroller units 300, so that the microcontroller units 300 can perform feedforward adjustment of the opening of the expansion valve 200, and timely increase or decrease the refrigerant flow of the microchannel 110 to avoid "air blockage" and avoid increasing the flow resistance of the refrigerant.

[0058] The microcontroller unit 300 feeds back the real-time temperature of the heating element 10, the signals from each inlet pressure sensor 112 and each outlet pressure sensor 111 to the host computer. The host computer is electrically connected to the compressor 500 and the condenser 600.

[0059] The microcontroller unit 300 uploads the collected real-time temperature data, inlet refrigerant pressure data, and outlet refrigerant pressure data to the host computer. The host computer uses the real-time power signal of each heating element 10 (calculated by collecting the current and voltage signals of the heating element 10, where power equals the product of current and voltage) as a feedforward control quantity. When the relative power change rate ΔP% / Δt of the heating element 10 is detected to be ≥10% / s or ΔP% / Δt≤-10% / s (initial power is P0, and after time Δt, the power becomes P1, ΔP%=(P1-P0) / P0×100%, and the relative power change rate is positive, it indicates that the power of the heating element 10 is positive), the power of the heating element 10 is positive. When the power relative change rate is negative (indicating a decrease in the power of the heating element 10), the host computer sends a signal to the microcontroller unit 300, which then adjusts the opening of the expansion valve 200 in advance. This achieves the function of feedforward compensation adjustment of the opening of the corresponding expansion valve 200, thereby offsetting the temperature fluctuation caused by the sudden change in the power of the heating element 10, avoiding "air blockage", reducing the flow resistance of the refrigerant in the microchannel 110, ensuring the cooling effect of the cooling plate 100, and reducing the energy consumption of the compressor 500.

[0060] In this embodiment, refer to Figure 1 The microchannel 110 has an inlet pipe connected to its inlet. Along the refrigerant flow direction, the inlet pipe is sequentially equipped with an inlet pressure sensor 112, an inlet shut-off valve 114, a filter assembly 113, and an expansion valve 200. The microchannel 110 has an outlet pipe connected to its outlet. Along the refrigerant flow direction, the outlet pipe is sequentially equipped with an outlet shut-off valve 115 and an outlet pressure sensor 111. (Refer to...) Figure 2 The microchannel 110 is connected to an inlet pipe and an outlet pipe. The ends of all outlet pipes away from the cooling plate 100 are connected to the same main outlet pipe, thus realizing the parallel connection of the cooling plate 100.

[0061] The present invention also discloses a cooling method applied to any of the above-mentioned embodiments of microchannel controllable phase change cooling backplates under micro-positive pressure.

[0062] The cooling method is applied to a microchannel controllable phase change cooling backplate under micro-positive pressure, including multiple cooling plates 100, each cooling plate 100 having a microchannel 110. An expansion valve 200 is provided at the inlet of the microchannel 110, through which the cooled refrigerant flows. The cooling plate 100 is used to contact the heating device 10 to transfer heat. The cooling plate 100 and the heating device 10 are in one-to-one correspondence. The flow rate of the refrigerant in the microchannel 110 can be controlled by adjusting the opening of the expansion valve 200. The refrigerant is used to cool the heating device 10. Cooled refrigerant is introduced into expansion valve 200. After flowing through expansion valve 200, the cooled refrigerant changes from liquid phase to gas phase. The gas phase refrigerant flows through microchannel 110. The power consumption of each heating element 10 is collected. When the relative power change rate of the heating element 10 is ≥10% / s or ≤-10% / s, feedforward compensation is performed to adjust the opening of the expansion valve 200 to counteract the temperature fluctuation caused by the power change of the heating element 10. The initial power is P0, and the power becomes P1 after time Δt. ΔP% = (P1-P0) / P0 × 100%. The real-time temperature T of each heating element 10 is collected to obtain the temperature change rate ΔT / Δt of each heating element 10. The opening of the expansion valve 200 is adjusted by the real-time temperature T and the temperature change rate ΔT / Δt. The initial temperature is T1, and the temperature after time Δt is T2, where ΔT = T2 - T1. When T < Tmin, Tmin is the lower limit of the optimal operating temperature of the heating device 10, and the opening of the expansion valve 200 is reduced to the minimum threshold. When Tmin≤T≤Tmax, and -0.5℃ / s≤ΔT / Δt≤0.5℃ / s, Tmax is the upper limit of the optimal operating temperature of the heating device 10, and the expansion valve 200 is maintained at the current opening. When T > Tmax or ΔT / Δt > 0.5℃ / s, increase the opening of expansion valve 200.

[0063] Understandably, Δt is 0.1-1s. The minimum threshold for the opening of expansion valve 200 is 5%-10%. The power of heating device 10 is obtained by collecting the current and voltage of heating device 10; the power is equal to the product of current and voltage. Cooled refrigerant is supplied to expansion valve 200, and the opening of expansion valve 200 is controlled according to the refrigerant superheat. The target refrigerant superheat is set to 5-7℃, and the refrigerant superheat is the difference between the temperature of the refrigerant at the outlet of microchannel 110 and the refrigerant saturation temperature.

[0064] Let the initial power be P0. After time Δt, the power becomes P1. ΔP% = (P1 - P0) / P0 × 100%. When the relative power change rate ΔP% / Δt is positive, it indicates that the power of the heating device 10 is increasing. When the relative power change rate ΔP% / Δt is negative, it indicates that the power of the heating device 10 is decreasing.

[0065] When ΔT / Δt is positive, it indicates that the heating device 10 is heating up; when ΔT / Δt is negative, it indicates that the heating device 10 is cooling down. Specifically, ΔT = T2 - T1, Δt = t2 - t1, t1 and T1 represent the initial time and temperature values ​​per unit time, respectively, and t2 and T2 represent the final time and temperature values ​​per unit time, respectively.

[0066] When T < Tmin, regardless of the magnitude of the temperature change rate ΔT / Δt, it proves that the heating device 10 has not reached the lower limit of the optimal operating temperature. Therefore, there is no need to increase the refrigerant flow rate of the microchannel 110; simply maintaining the minimum refrigerant flow rate of the microchannel 110 is sufficient.

[0067] When Tmin≤T≤Tmax and the temperature change rate -0.5℃ / s≤ΔT / Δt≤0.5℃ / s, it proves that the temperature fluctuation range of the heating device 10 is small, which can maintain the expansion valve 200 at the current opening degree without frequent adjustment of the opening degree of the expansion valve 200, so that the heating device 10 is in the best stable working state.

[0068] When the temperature change rate ΔT / Δt > 0.5℃ / s, it indicates a sharp increase in the temperature of the heating element 10; conversely, when the temperature change rate ΔT / Δt ≤ -0.5℃ / s, it indicates a sharp decrease in the temperature of the heating element 10. When T > Tmax or ΔT / Δt > 0.5℃ / s, the opening of the expansion valve 200 needs to be increased to increase the refrigerant flow rate of the microchannel 110, thereby improving the cooling effect of the cooling plate 100 and providing timely cooling for the heating element 10.

[0069] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0070] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A microchannel controllable phase change cooling backplate under micro-positive pressure, characterized in that, include: Multiple cooling plates (100) are arranged in parallel. Each cooling plate (100) has a microchannel (110). An expansion valve (200) is provided at the inlet of the microchannel (110). The expansion valve (200) and the microchannel (110) allow the cooled refrigerant to flow through. The cooling plate (100) is used to contact the heating device (10) to transfer heat. The cooling plate (100) and the heating device (10) correspond one-to-one. Multiple microcontroller units (300) and multiple first temperature sensors (400) are provided, with the cooling plate (100), the microcontroller units (300) and the first temperature sensors (400) arranged in a one-to-one correspondence. The first temperature sensors (400) and the expansion valve (200) are both electrically connected to the microcontroller units (300). The first temperature sensors (400) are used to collect the real-time temperature T of the heating device (10). The microcontroller units (300) are configured to receive the temperature signal fed back from the first temperature sensors (400) and control the opening degree of the expansion valve (200), and make the opening degree of the expansion valve (200) positively correlated with the real-time temperature T.

2. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 1, characterized in that, A heat insulation layer (120) is connected to one side of the cooling plate (100), and the microcontroller unit (300) is disposed on the side of the heat insulation layer (120) away from the cooling plate (100).

3. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 1, characterized in that, A heat-conducting layer (130) is provided between the cooling plate (100) and the heating device (10), and the heat-conducting layer (130) is used to conduct the heat of the heating device (10) to the cooling plate (100).

4. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 3, characterized in that, The thermally conductive layer (130) may be a liquid metal layer.

5. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 1, characterized in that, The microchannel (110) is provided with a filter assembly (113) at its inlet, and the filter assembly (113) and the corresponding expansion valve (200) are arranged sequentially along the flow direction of the refrigerant.

6. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 5, characterized in that, The microchannel (110) is provided with an inlet shut-off valve (114) at its inlet. The inlet shut-off valve (114), the filter assembly (113), and the expansion valve (200) are arranged along the flow direction of the refrigerant. The microchannel (110) is provided with an outlet shut-off valve (115) at its outlet.

7. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 1, characterized in that, The outlet of the microchannel (110) is provided with an outlet pressure sensor (111), which is used to detect the pressure of the refrigerant at the outlet of the microchannel (110).

8. The microchannel controllable phase change cooling backplate under micro-positive pressure according to claim 1 or 7, characterized in that, The inlet of the microchannel (110) is provided with an inlet pressure sensor (112), which is used to detect the pressure of the refrigerant at the inlet of the microchannel (110).

9. A cooling method, characterized in that, The microchannel controllable phase change cooling backplate under micro-positive pressure according to any one of claims 1 to 8 comprises the following steps: The microchannel controllable phase change cooling backplate under micro-positive pressure includes multiple cooling plates (100), each of which has a microchannel (110). The inlet of the microchannel (110) is provided with an expansion valve (200). The expansion valve (200) and the microchannel (110) allow cooled refrigerant to flow through. The cooling plate (100) is used to contact the heating device (10) to transfer heat. The cooling plate (100) and the heating device (10) correspond one-to-one. The flow rate of the refrigerant in the microchannel (110) can be controlled by adjusting the opening of the expansion valve (200). The refrigerant is used to cool the heating device (10). The cooled refrigerant is introduced into the expansion valve (200). After flowing through the expansion valve (200), the cooled refrigerant changes from a liquid phase to a gas phase. The gas phase refrigerant flows through the microchannel (110). The power consumption of each of the heating devices (10) is collected. When the relative power change rate of the heating device (10) ΔP% / Δt ≥ 10% / s or ΔP% / Δt ≤ -10% / s, feedforward compensation is performed to adjust the opening of the expansion valve (200) to offset the temperature fluctuation caused by the power change of the heating device (10). The initial power is P0, and the power becomes P1 after time Δt. ΔP% = (P1 - P0) / P0 × 100%. The real-time temperature T of each of the heating devices (10) is collected to obtain the temperature change rate ΔT / Δt of each of the heating devices (10). The opening degree of the expansion valve (200) is adjusted by the real-time temperature T and the temperature change rate ΔT / Δt. The initial temperature is T1, and the temperature after time Δt is T2. ΔT = T2 - T1. When T < Tmin, Tmin is the lower limit of the optimal operating temperature of the heating device (10), and the opening of the expansion valve (200) is reduced to the minimum threshold. When Tmin≤T≤Tmax, and -0.5℃ / s≤ΔT / Δt≤0.5℃ / s, Tmax is the upper limit of the optimal operating temperature of the heating device (10), and the expansion valve (200) is maintained at the current opening. When T > Tmax or ΔT / Δt > 0.5℃ / s, increase the opening of the expansion valve (200).

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