Method and device for adjusting electronic expansion valve in multi-connected unit, and multi-connected unit

Abstract

The application relates to a method and device for adjusting an electronic expansion valve in a multi-connected unit, and the multi-connected unit, wherein the method comprises the following steps: collecting a high-pressure value of a compressor exhaust port and an exhaust temperature of the compressor in the multi-connected unit; determining a first difference value between the high-pressure value and a first preset threshold value; determining an exhaust superheat degree based on the exhaust temperature and the high-pressure value, and determining a second difference value between the exhaust superheat degree and a second preset threshold value; determining a first proximity level between the high-pressure value and a first preset protection value based on the first difference value, and determining a second proximity level between the exhaust superheat degree and a second preset protection value based on the second difference value; comparing the first proximity level with the second proximity level, and determining whether to adjust the opening degree of the first electronic expansion valve based on a comparison result, so as to balance the high-pressure of the multi-connected unit and the exhaust superheat degree. Through the multi-connected unit in the application, the electronic expansion valve can be cooperatively controlled by two parameters, so that the multi-connected unit has an energy-saving effect.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a method and device for adjusting the electronic expansion valve in a multi-split air conditioner, and the multi-split air conditioner itself. Background Technology

[0002] During the heating operation of a multi-split air conditioning system, especially in transitional seasons (such as autumn and winter), most indoor units are shut down, while a few remain operational. In this situation, an improperly set electronic expansion valve (EXV) opening on the shut-down indoor unit will directly affect the system's high-pressure and compressor discharge superheat. If the EXV opening is too small, the system high pressure may approach the protection threshold, triggering high-pressure protection; conversely, if the EXV opening is too large, the system discharge superheat may be too low, triggering low-temperature discharge protection. These issues can lead to frequent system shutdowns, impacting operational stability and energy efficiency.

[0003] Currently, existing technologies for controlling electronic expansion valves typically employ fixed EXV opening degrees or single threshold judgment logic for adjustment, lacking a dynamic response mechanism for the real-time operating status of the system, and making it difficult to simultaneously meet the dual protection requirements of high pressure and exhaust superheat. Summary of the Invention

[0004] This application provides a method and device for adjusting the electronic expansion valve in a multi-split air conditioning system, and the multi-split air conditioning system, to solve the problem that the existing technology uses a fixed EXV opening degree or a single threshold judgment logic to adjust the electronic expansion valve during the heating operation of the multi-split air conditioning system, which makes it difficult to meet the dual protection requirements of high pressure and exhaust superheat.

[0005] In a first aspect, this application provides a method for adjusting an electronic expansion valve in a multi-split air conditioning system, comprising: acquiring a high-pressure value at the compressor exhaust port and a compressor exhaust temperature in the multi-split air conditioning system; determining a first difference between the high-pressure value and a first preset threshold; determining exhaust superheat based on the exhaust temperature and the high-pressure value, and determining a second difference between the exhaust superheat and a second preset threshold; determining a first proximity level between the high-pressure value and a first preset protection value based on the first difference, and determining a second proximity level between the exhaust superheat and the second preset protection value based on the second difference; comparing the first proximity level and the second proximity level, and determining, based on the comparison result, whether to adjust the opening of a first electronic expansion valve to balance the high-pressure and exhaust superheat of the multi-split air conditioning system, wherein the first electronic expansion valve is the first electronic expansion valve of the indoor unit in the multi-split air conditioning system in a stopped state.

[0006] Optionally, determining whether to adjust the opening of the first electronic expansion valve based on the comparison result includes: obtaining the absolute value between the first proximity level and the second proximity level, and determining an initial adjustment range for adjusting the opening of the first electronic expansion valve based on the absolute value; adjusting the initial adjustment range based on the target parameters of the indoor units in each shutdown state to determine a final adjustment range; wherein the target parameters include the equivalent length of the pipeline from the indoor unit to the outdoor unit; and adjusting the opening of the first electronic expansion valve of the indoor units in each shutdown state based on the final adjustment range.

[0007] Optionally, the initial adjustment range is adjusted based on the target parameters of the indoor units in each shutdown state to determine the final adjustment range, including: obtaining the equivalent length of the pipeline from the indoor unit to the outdoor unit in each shutdown state, and determining the weight of the indoor unit in each shutdown state based on the equivalent length of the pipeline, wherein the longer the equivalent length of the pipeline, the greater the weight; and determining the final adjustment range by multiplying the weight by the initial adjustment range.

[0008] Optionally, determining a first proximity level between the high-pressure value and the first preset protection value based on the first difference includes: determining the first proximity level based on the first difference and a first mapping table, wherein the first mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the high-pressure value and the first preset protection value; determining a second proximity level between the exhaust superheat and the second preset protection value based on the second difference includes: determining the second proximity level based on the second difference and a second mapping table, wherein the second mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the exhaust superheat and the second preset protection value.

[0009] Optionally, the method further includes: adjusting the mapping relationship between the first mapping table and the second mapping table in real time based on the outdoor ambient temperature, wherein the lower the outdoor ambient temperature, the smaller the range of the difference.

[0010] Optionally, determining whether to adjust the opening of the first electronic expansion valve based on the comparison result includes: increasing the opening of the first electronic expansion valve when the first proximity level is greater than the second proximity level; decreasing the opening of the first electronic expansion valve when the first proximity level is less than the second proximity level; and maintaining the current opening of the first electronic expansion valve when the first proximity level is equal to the second proximity level.

[0011] Optionally, the method further includes: when the first proximity level is greater than the second proximity level, and the difference between the first proximity level and the second proximity level exceeds a preset threshold, while increasing the opening of the first electronic expansion valve, simultaneously increasing the opening of the second electronic expansion valve of the indoor unit that is in operation.

[0012] Secondly, this application provides an adjustment device for an electronic expansion valve in a multi-split air conditioner, comprising: a data acquisition module for acquiring the high-pressure value of the compressor exhaust port and the compressor exhaust temperature in the multi-split air conditioner; a first processing module for determining a first difference between the high-pressure value and a first preset threshold; a second processing module for determining exhaust superheat based on the exhaust temperature and the high-pressure value, and determining a second difference between the exhaust superheat and a second preset threshold; a third processing module for determining a first proximity level between the high-pressure value and a first preset protection value based on the first difference, and determining a second proximity level between the exhaust superheat and the second preset protection value based on the second difference; and a fourth processing module for comparing the first proximity level and the second proximity level, and determining, based on the comparison result, whether to adjust the opening of the first electronic expansion valve to balance the high-pressure and exhaust superheat of the multi-split air conditioner, wherein the first electronic expansion valve is the first electronic expansion valve of the indoor unit in the multi-split air conditioner in a stopped state.

[0013] Thirdly, this application provides a multi-unit air conditioner, comprising: at least one communication interface; at least one bus connected to the at least one communication interface; at least one processor connected to the at least one bus; and at least one memory connected to the at least one bus, wherein the processor is configured to perform a method for using an electronic expansion valve in a multi-unit air conditioner as described in the first aspect of this application.

[0014] Fourthly, this application also provides a computer storage medium storing computer-executable instructions for performing the method of using an electronic expansion valve in a multi-split air conditioner as described in the first aspect of this application.

[0015] Compared with the prior art, the technical solution provided in this application has the following advantages: The method provided in this application first collects the high-pressure value of the compressor exhaust port and the compressor exhaust temperature in the multi-split air conditioner. Then, it determines the first difference between the high-pressure value and a first preset threshold, and determines the exhaust superheat based on the exhaust temperature and high-pressure value. It then determines the second difference between the exhaust superheat and a second preset threshold. Based on the first difference, it determines the first proximity level between the high-pressure value and a first preset protection value, and based on the second difference, it determines the second proximity level between the exhaust superheat and the second preset protection value. Finally, it compares the first proximity level and the second proximity level, and determines whether to adjust the opening of the first electronic expansion valve based on the comparison result to balance the high-pressure and exhaust superheat of the multi-split air conditioner. It can be seen that in this application embodiment, the high-pressure and exhaust superheat are coordinated and adjusted. Compared to relying solely on high-pressure adjustment, which tends to increase the EXV to reduce high pressure, if the exhaust superheat is already low, further increasing the EXV will lead to a further decrease in exhaust superheat, making it easier to trigger the exhaust low-temperature protection. Conversely, relying solely on exhaust superheat adjustment can lead to a reduction in the EXV (exhaust pressure) to increase superheat, potentially causing a rapid rise in high pressure and triggering high-pressure protection. However, by simultaneously monitoring both parameters (high pressure and exhaust superheat), it's possible to identify which parameter is more dangerous (closer to the protection value) and find a dynamic balance between high pressure and exhaust superheat. Specifically, the higher the parameter level, the more preferentially the corresponding electronic expansion valve adjustment method is used, preventing the other parameter from becoming uncontrollable in order to adjust one. In other words, by adjusting the electronic expansion valve through dual-parameter collaborative control in this embodiment, proactive intervention can be performed before the system triggers protection, improving system stability and energy efficiency. Attached Figure Description

[0016] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0019] Figure 1 A flowchart illustrating a method for adjusting an electronic expansion valve in a multi-split air conditioning system, as provided in this application embodiment; Figure 2 A flowchart of the self-adjusting control method for the electronic expansion valve of the multi-unit thermal shutdown indoor unit provided in this application embodiment; Figure 3 A flowchart of the adjustment device for the electronic expansion valve in a multi-split air conditioner provided in this application embodiment; Figure 4 This is a schematic diagram of the structure of a multi-split air conditioner provided in an embodiment of this application. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0022] To address the problem that existing technologies using fixed EXV openings or single threshold logic to adjust the electronic expansion valve during multi-split air conditioning systems make it difficult to simultaneously meet the dual protection requirements of high pressure and exhaust superheat, this application provides a method for adjusting the electronic expansion valve in multi-split air conditioning systems, such as... Figure 1 As shown, the steps of this method include: Step 101: Collect the high pressure value at the compressor discharge port and the compressor discharge temperature in the multi-split unit; In this embodiment, high pressure refers to the pressure at the compressor discharge port, which is the pressure on the condenser side of the refrigeration system. In heating mode, it reflects the actual pressure value on the high-pressure side of the system. High pressure is the basis for determining whether a multi-split air conditioning system may trigger high-pressure protection. If the high pressure is too high, it indicates that the condenser pressure is too high, which may cause the system to enter a high-pressure protection state, thereby shutting down to protect the compressor. Therefore, by monitoring the high pressure, it is possible to determine in advance whether the opening of the electronic expansion valve (EXV) of the shut-down indoor unit needs to be adjusted to reduce the system pressure and avoid triggering the protection.

[0023] Step 102, determine the first difference between the high-pressure pressure value and the first preset threshold value; Step 103, determine the superheat degree of the exhaust gas based on the exhaust gas temperature and the high-pressure pressure value, and determine the second difference between the superheat degree of the exhaust gas and the second preset threshold value; In the embodiment of the present application, the superheat degree of the exhaust gas refers to the difference between the compressor exhaust gas temperature and the saturation temperature corresponding to the high-pressure pressure, that is: the superheat degree of the exhaust gas = T 排气 -T 饱和（对应高压压力） . It should be noted that in the heating model of the multi-connected unit, the higher the high-pressure pressure value, the higher the corresponding saturation temperature, that is, the two are positively correlated in this case. Therefore, the corresponding saturation temperature can be determined through the high-pressure pressure value, and then the corresponding superheat degree of the exhaust gas can be determined according to the exhaust gas temperature and the saturation temperature. In a specific example, the corresponding saturation temperature can be determined by looking up the saturation temperature-pressure correspondence table through the high-pressure pressure value.

[0024] Step 104, determine the first proximity level between the high-pressure pressure value and the first preset protection value based on the first difference, and determine the second proximity level between the superheat degree of the exhaust gas and the second preset protection value based on the second difference; The first difference and the second difference in the embodiment of the present application represent the proximity degree between the high pressure and the superheat degree of the exhaust gas and the corresponding protection values (the first preset protection value and the second preset protection value). The smaller the difference (the first difference and the second difference), the closer it is to the protection value, that is, the greater the proximity degree. That is to say, the smaller the difference, the higher the corresponding proximity level.

[0025] Step 105, compare the first proximity level and the second proximity level, and determine whether to adjust the opening degree of the first electronic expansion valve based on the comparison result to balance the high-pressure pressure and the superheat degree of the exhaust gas of the multi-connected unit, wherein the first electronic expansion valve is the first electronic expansion valve of the indoor unit in the shutdown state of the multi-connected unit.

[0026] It can be seen from this that in the embodiment of the present application, the high-pressure pressure and the superheat degree of the exhaust gas are jointly used to judge the current dangerous tendency of the system: if the high pressure is closer to the protection value (Dh > Dp), it means that the system has a high-pressure risk and the EXV should be opened wider to reduce the high pressure; if the superheat degree of the exhaust gas is closer to the protection value (Dh < Dp), it means that the system has a low-temperature risk and the EXV should be closed smaller to increase the superheat degree of the exhaust gas; if the proximity degrees of the two are the same, the current EXV opening degree is maintained.

[0027] Through steps 101 to 105 above, the high-pressure value of the compressor exhaust port and the compressor exhaust temperature in the multi-split air conditioner are first collected. Then, the first difference between the high-pressure value and the first preset threshold is determined, and the exhaust superheat is determined based on the exhaust temperature and the high-pressure value. The second difference between the exhaust superheat and the second preset threshold is then determined. Based on the first difference, the first proximity level between the high-pressure value and the first preset protection value is determined, and based on the second difference, the second proximity level between the exhaust superheat and the second preset protection value is determined. Finally, the first proximity level and the second proximity level are compared, and based on the comparison result, it is determined whether to adjust the opening of the first electronic expansion valve to balance the high-pressure and exhaust superheat of the multi-split air conditioner. It can be seen that in this embodiment, the high-pressure and exhaust superheat are coordinated and regulated. Compared to relying solely on high-pressure regulation, which tends to increase the EXV to reduce high pressure, this approach is more effective. However, if the exhaust superheat is already low, further increasing the EXV will lead to a further decrease in exhaust superheat, making it easier to trigger the exhaust low-temperature protection. Conversely, relying solely on exhaust superheat adjustment can lead to a reduction in the EXV (exhaust pressure) to increase superheat, potentially causing a rapid rise in high pressure and triggering high-pressure protection. However, by simultaneously monitoring both parameters (high pressure and exhaust superheat), it's possible to identify which parameter is more dangerous (closer to the protection value) and find a dynamic balance between high pressure and exhaust superheat. Specifically, the higher the parameter level, the more preferentially the corresponding electronic expansion valve adjustment method is used, preventing the other parameter from becoming uncontrollable in order to adjust one. In other words, by adjusting the electronic expansion valve through dual-parameter collaborative control in this embodiment, proactive intervention can be performed before the system triggers protection, improving system stability and energy efficiency.

[0028] In an optional embodiment of this application, the method of determining whether to adjust the opening of the first electronic expansion valve based on the comparison result in step 105 above may further include: Step 11: If the first proximity level is greater than the second proximity level, increase the opening of the first electronic expansion valve. Step 12: If the first proximity level is less than the second proximity level, reduce the opening of the first electronic expansion valve. Step 13: If the first proximity level is equal to the second proximity level, maintain the current opening of the first electronic expansion valve.

[0029] As shown in steps 11 to 13 above, if the high pressure is closer to the protection value, it indicates a high pressure risk in the system, and the EXV should be increased to reduce the high pressure; if the exhaust superheat is closer to the protection value, it indicates a low temperature risk in the system, and the EXV should be decreased to increase the exhaust superheat; if both are equally close, the current EXV opening should be maintained. This dual-parameter coordinated adjustment method can proactively intervene before the system triggers protection, improving the stability and energy efficiency of system operation. Furthermore, in certain special circumstances, compensation adjustments can be made in conjunction with the operating indoor unit. Specifically, when the system determines that the high-pressure risk is extremely high (e.g., the first proximity level is much higher than the second proximity level, and the EXV of the shut-down indoor unit is already at Fmax but still cannot effectively reduce the pressure), the operating indoor unit can be activated for auxiliary adjustment. This involves appropriately increasing the EXV of the running indoor unit to reduce refrigerant flow resistance and further lower the system high pressure. Based on this, the method in the embodiments of this application may also include: Step 106: When the first proximity level is greater than the second proximity level and the difference between the first proximity level and the second proximity level exceeds a preset threshold, the opening of the first electronic expansion valve is increased while the opening of the second electronic expansion valve of the indoor unit that is in operation is also increased.

[0030] In an optional embodiment of this application, to make the adjustment of the electronic expansion valve more precise, the initial adjustment range can be determined by combining the absolute value between the first proximity level and the second proximity level. Then, the initial adjustment range can be adjusted again by combining the equivalent length of the pipeline from the stopped indoor unit to the outdoor unit to determine the final adjustment range. The electronic expansion valve can then be precisely adjusted using the final adjustment range. Therefore, the method of determining whether to adjust the opening of the first electronic expansion valve based on the comparison result in step 105 above can further include: Step 21: Obtain the absolute value between the first proximity level and the second proximity level, and determine the initial adjustment range of the opening of the first electronic expansion valve based on the absolute value; Step 22: Adjust the initial adjustment range based on the target parameters of the indoor unit in each shutdown state to determine the final adjustment range; wherein, the target parameters include the equivalent length of the pipeline from the indoor unit to the outdoor unit; Step 23: Adjust the opening degree of the first electronic expansion valve of each indoor unit in the shutdown state based on the final adjustment range.

[0031] In this specific example, the relationship between proximity level and difference can be obtained through a preset table, as shown in Table 1.

[0032] Table 1

[0033] Where Dh represents the first proximity level, ΔH represents the first difference, Dp represents the second proximity level, and ΔP represents the second difference. It should be noted that Dh and Dp represent the degree of proximity between the high pressure / exhaust superheat and the preset protection value. The smaller the difference ΔH / ΔP between the high pressure / exhaust superheat and the preset protection value, the closer it is to the protection value, and the greater the degree of proximity. In the specific example, Dh and Dp are obtained by looking up the difference ΔH / ΔP between the high pressure / exhaust superheat and the preset protection value according to the corresponding table. For example, if the difference ΔH is between 0 and 0.5 MPa, then Dh = n. The value of n can be set according to actual needs.

[0034] As can be seen from steps 21 to 23 above, the opening of the first electronic expansion valve is coarsely adjusted by the absolute value between the first and second proximity levels. A large absolute value indicates extremely high risk on one side, requiring a large and rapid correction. A small absolute value indicates the system is in a relatively balanced but slightly skewed state, requiring less correction. This tiered adjustment strategy makes the control action more refined, ensuring both response speed and avoiding system oscillations caused by over-adjustment. Then, the opening of the first electronic expansion valve is finely adjusted by considering the equivalent length of the pipeline from the indoor unit to the outdoor unit in each stopped state. This means treating all stopped indoor units as a whole and uniformly adjusting their opening. Then, considering the different contributions or sensitivities of the pipeline length caused by the installation location of the stopped indoor units to system high pressure and superheat, differentiated adjustments are made to make the system pressure regulation more balanced.

[0035] Specifically, the initial adjustment range can be obtained through a preset table, which contains a preset relationship between absolute values ​​and the initial adjustment range, as shown in Table 2.

[0036] Table 2

[0037] Where Cn-1 pls represents the specific initial adjustment range, and pls represents the actual position or percentage of opening of the solenoid valve spool, thereby precisely controlling the flow rate, pressure, or direction of the fluid. As shown in the table above, if the proximity level difference is 0, the adjustment range is 0, i.e., maintaining the current opening degree; while proximity level differences of 1 to n-1 correspond to EXV adjustment ranges of C1 to Cn-1 pls, with larger differences resulting in larger EXV opening adjustment ranges.

[0038] The method of adjusting the initial adjustment range based on the target parameters of the indoor unit in each shutdown state to determine the final adjustment range, as mentioned in step 22 above, may further include: Step 31: Obtain the equivalent length of the pipe from the indoor unit to the outdoor unit in each shutdown state, and determine the weight of the indoor unit in each shutdown state based on the equivalent length of the pipe. The longer the equivalent length of the pipe, the greater the weight. Step 32: The product of the weight and the initial adjustment range is determined as the final adjustment range.

[0039] In specific examples, the equivalent pipe length from the indoor unit to the outdoor unit in each shutdown state can be obtained in several ways. One approach is that during system installation and commissioning, installers can calculate the equivalent length according to preset conversion rules based on the actual pipe layout, including straight pipe length, number of bends, and lifting height, and write it into the control system's memory. Another approach is that multi-split systems can automatically identify the equivalent length using the communication function between the indoor and outdoor units: after the unit is powered on, the equivalent length is estimated by detecting the attenuation or round-trip time of the communication signal, or based on the preset relationship between the indoor unit address and the pipe topology. Furthermore, preset equivalent length values ​​can be retrieved from a database by combining information such as the indoor unit's capacity and model. Regardless of the method used, the obtained equivalent pipe length will be used for subsequent weight calculations to address the problem of delayed adjustment response of remote indoor units in long or complex piping systems, resulting in more balanced system pressure regulation.

[0040] Therefore, since the longer the indoor unit's piping, the less sensitive its EXV opening changes are to the system's high pressure, a larger number of adjustment steps are needed. Specifically, a standard equivalent piping length can be preset. This means that if the equivalent piping length from the currently shut-down indoor unit to the outdoor unit is the same as this standard equivalent piping length, the adjustment coefficient determined by the equivalent piping length is 1. In other words, the initial adjustment range at this time is the final adjustment range. If the equivalent piping length from the currently shut-down indoor unit to the outdoor unit is greater than this standard equivalent piping length, the weight determined by the equivalent piping length is greater than 1, and the final adjustment range at this time is the product of this weight greater than 1 and the initial adjustment range. Conversely, if the equivalent piping length from the currently shut-down indoor unit to the outdoor unit is less than this standard equivalent piping length, the weight determined by the equivalent piping length is less than 1, and the final adjustment range at this time is the product of this weight less than 1 and the initial adjustment range. The specific weight can be determined by the ratio of the actual equivalent length of the pipeline to the equivalent length of the standard pipeline.

[0041] The above methods can solve the problem of delayed adjustment response of remote indoor units in long piping or complex piping systems, making the system pressure regulation more balanced.

[0042] In an optional embodiment of this application, the method of determining the first proximity level between the high-pressure value and the first preset protection value based on the first difference mentioned in 104 above may further include: determining the first proximity level based on the first difference and a first mapping table, wherein the first mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the high-pressure value and the first preset protection value. The method of determining the second proximity level between exhaust superheat and the second preset protection value based on the second difference mentioned in step 104 above can further include: determining the second proximity level based on the second difference and the second mapping table, wherein the second mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between exhaust superheat and the second preset protection value.

[0043] In a specific example, as shown in Table 1 above, after determining the difference value, the corresponding proximity level can be determined by looking up the table.

[0044] It should be noted that outdoor ambient temperature has a significant impact on the system's operating characteristics. In low-temperature environments, the slope of the refrigerant saturation pressure versus temperature curve is steeper, and the high-pressure is more sensitive to temperature changes; simultaneously, the compressor discharge superheat changes more drastically. This means that in low-temperature environments, even small pressure or temperature fluctuations can cause the system to approach its protection value, thus requiring more precise control. Using the same difference range division as when the ambient temperature is higher may result in insufficient control resolution, failing to promptly detect dangerous trends. Therefore, this application adjusts the mapping table in real time based on the outdoor ambient temperature: when the outdoor ambient temperature decreases, the difference range is correspondingly narrowed, i.e., the resolution of the proximity level is improved, enabling a more accurate assessment of the proximity of the high pressure and discharge superheat to the protection value at low temperatures, thereby allowing for more accurate electronic expansion valve adjustment and avoiding protection triggering due to control lag. In other words, in this embodiment, the mapping relationship in the first and second mapping tables can also be adjusted in real time based on the outdoor ambient temperature, where a lower outdoor ambient temperature corresponds to a smaller difference range.

[0045] The following detailed description, in conjunction with specific embodiments of this application, provides a self-regulating control method for the electronic expansion valve of a multi-unit thermal shutdown indoor unit. Figure 2 As shown, the steps of this method include: Step 201: Preset the high-pressure protection value Hb and the exhaust superheat protection value Pb; The control system presets a high-pressure protection value Hb and an exhaust superheat protection value Pb. When the high pressure is greater than or equal to Hb, the system will trigger high-pressure protection. When the indoor unit detects exhaust superheat less than or equal to Pb for t minutes consecutively, the system will trigger exhaust low-temperature protection.

[0046] Step 202: Real-time acquisition of high pressure value H0 and compressor exhaust temperature value T0, and calculation of exhaust superheat P0=T0-H0; Step 203, let ΔH = Hb - H0 and ΔP = P0 - Pb; Step 204: Determine the proximity level Dh and Dp between the high pressure or exhaust superheat and the protection value based on the differences ΔH and ΔP. During unit operation, the high-pressure value H0 and the compressor exhaust temperature T0 are collected in real time. The exhaust superheat P0 = T0 - H0 is calculated, and the differences between it and the preset protection value are calculated as ΔH = Hb - H0 and ΔP = P0 - Pb. Based on the differences ΔH and ΔP, the proximity level Dh and Dp between the high-pressure or exhaust superheat and the preset protection value are determined. The smaller the difference, the larger the proximity level, indicating that it is closer to the protection value.

[0047] Step 205: If Dh > Dp, it means that the proximity level between the high pressure value and the protection value is greater than that between the exhaust superheat value and the protection value. In this case, it is determined that the high pressure is closer to the protection limit. At this time, the opening of the shutdown indoor unit EXV should be increased to reduce the system high pressure. Step 206: If Dh < Dp, it means that the proximity level between the high pressure value and the protection value is less than the proximity level between the exhaust superheat and the protection value. Therefore, it is determined that the exhaust superheat is closer to the protection limit. At this time, the opening of the shutdown indoor unit EXV should be reduced to increase the system exhaust superheat. Step 207: If Dh = Dp, it means that the proximity level between the high pressure value and the protection value is equal to the proximity level between the exhaust superheat and the protection value. Then maintain the current EXV opening of the shut-down indoor unit. Step 208: Based on the absolute value of the difference between the high pressure and the exhaust superheat level (▕Dh- Dp▕), adjust the EXV opening range accordingly. Step 209, set the minimum opening degree F of the indoor unit EXV to be stopped. min and maximum opening F max When the indoor unit is stopped, the EXV opening should not exceed this adjustment range to prevent over-adjustment. Step 210: When the system triggers protection due to excessively high pressure or excessively low exhaust temperature, the control system records the opening value of the indoor unit EXV at this time and uses this value as a reference to automatically adjust and correct it during the next startup, so as to realize the adaptive adjustment function.

[0048] As can be seen, in this embodiment, a dual-parameter detection mechanism for high pressure and exhaust superheat is introduced during the hot operation of the multi-unit system. Furthermore, based on the difference in the degree to which the high pressure and exhaust superheat approach the protection value, the EXV opening of the indoor unit is dynamically adjusted. The EXV opening adjustment range adopts a graded adjustment strategy, that is, different EXV opening adjustment ranges are executed according to the absolute value of the difference between the proximity levels of the high pressure and exhaust superheat. In other words, by dynamically adjusting the EXV opening of the indoor unit based on the degree to which the high pressure and exhaust superheat approach the preset protection value detected by the system in real time, the system can achieve a balance between high pressure and exhaust superheat, avoiding triggering the protection mechanism. By setting a threshold for the EXV opening adjustment range, new operational instability problems are prevented due to excessive adjustment range. By memorizing and correcting the EXV opening after protection is triggered, the system has adaptive adjustment capabilities for the next startup, thereby achieving a more intelligent and stable control effect.

[0049] Corresponding to the above Figure 1 This application also provides an adjustment device for the electronic expansion valve in a multi-split air conditioning system, such as... Figure 3 As shown, the device includes: The data acquisition module 302 is used to acquire the high pressure value at the compressor discharge port and the compressor discharge temperature in the multi-split air conditioner. The first processing module 304 is used to determine a first difference between the high pressure value and a first preset threshold. The second processing module 306 is used to determine the exhaust superheat based on the exhaust temperature and high pressure value, and to determine a second difference between the exhaust superheat and a second preset threshold. The third processing module 308 is used to determine a first proximity level between the high pressure value and the first preset protection value based on the first difference, and to determine a second proximity level between the exhaust superheat and the second preset protection value based on the second difference. The fourth processing module 310 is used to compare the first proximity level with the second proximity level, and determine whether to adjust the opening of the first electronic expansion valve based on the comparison result in order to balance the high pressure and exhaust superheat of the multi-split unit. The first electronic expansion valve is the first electronic expansion valve of the indoor unit in the multi-split unit that is in the off state.

[0050] In an optional embodiment of this application, the fourth processing module includes: a first processing unit, configured to obtain the absolute value between the first proximity level and the second proximity level, and determine an initial adjustment range for adjusting the opening of the first electronic expansion valve based on the absolute value; a second processing unit, configured to adjust the initial adjustment range based on the target parameters of the indoor units in each shutdown state to determine the final adjustment range; wherein the target parameters include the equivalent length of the pipeline from the indoor unit to the outdoor unit; and a third processing unit, configured to adjust the opening of the first electronic expansion valve of the indoor units in each shutdown state based on the final adjustment range.

[0051] In an optional embodiment of this application, the second processing unit in this application includes: an acquisition subunit, used to acquire the equivalent length of the pipe from the indoor unit to the outdoor unit in each shutdown state, and determine the weight of each indoor unit in each shutdown state based on the equivalent length of the pipe, wherein the longer the equivalent length of the pipe, the greater the corresponding weight; and a determination subunit, used to determine the final adjustment range by multiplying the weight by the initial adjustment range.

[0052] In an optional embodiment of this application, the third processing module includes: a fourth processing unit, configured to determine a first proximity level based on a first difference and a first mapping table, wherein the first mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the high pressure value and the first preset protection value; and a fifth processing unit, configured to determine a second proximity level based on a second difference and a second mapping table, wherein the second mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the exhaust superheat and the second preset protection value.

[0053] In an optional embodiment of this application, the apparatus in this application may further include: a fifth processing module, used to adjust the mapping relationship in the first mapping table and the second mapping table in real time based on the outdoor ambient temperature, wherein the lower the outdoor ambient temperature, the smaller the range of the difference.

[0054] In an optional embodiment of this application, the fourth processing module may include: a sixth processing unit, configured to increase the opening of the first electronic expansion valve when the first proximity level is greater than the second proximity level; a seventh processing unit, configured to decrease the opening of the first electronic expansion valve when the first proximity level is less than the second proximity level; and an eighth processing unit, configured to maintain the current opening of the first electronic expansion valve when the first proximity level is equal to the second proximity level.

[0055] In an optional embodiment of this application, the device in this application may further include: a sixth processing module, configured to, when the first proximity level is greater than the second proximity level and the difference between the first proximity level and the second proximity level exceeds a preset threshold, simultaneously increase the opening of the first electronic expansion valve and the opening of the second electronic expansion valve of the indoor unit that is currently in operation.

[0056] like Figure 4 As shown in the figure, this application embodiment provides a multi-split air conditioner, which includes a control device. The control device includes a processor 411, a communication interface 412, a memory 413, and a communication bus 414. The processor 411, the communication interface 412, and the memory 413 communicate with each other through the communication bus 414. Memory 413 is used to store computer programs; In one embodiment of this application, when the processor 411 executes the program stored in the memory 413, it implements the adjustment method of the electronic expansion valve in the multi-unit air conditioner provided in any of the aforementioned method embodiments. Its function is similar and will not be described again here.

[0057] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the adjustment method for the electronic expansion valve in a multi-split air conditioner as provided in any of the foregoing method embodiments.

[0058] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0059] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0060] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0061] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for adjusting the electronic expansion valve in a multi-split air conditioning system, characterized in that, include: Collect the high-pressure value at the compressor discharge port and the compressor discharge temperature in the multi-split air conditioner; Determine the first difference between the high-pressure value and the first preset threshold; The exhaust superheat is determined based on the exhaust temperature and the high pressure value, and a second difference between the exhaust superheat and a second preset threshold value is determined. Based on the first difference, a first proximity level is determined between the high-pressure value and the first preset protection value, and based on the second difference, a second proximity level is determined between the exhaust superheat and the second preset protection value. The first proximity level is compared with the second proximity level, and based on the comparison result, it is determined whether to adjust the opening of the first electronic expansion valve to balance the high pressure and exhaust superheat of the multi-split system. The first electronic expansion valve is the first electronic expansion valve of the indoor unit of the multi-split system that is in the off state.

2. The method according to claim 1, characterized in that, Determining whether to adjust the opening of the first electronic expansion valve based on the comparison results includes: Obtain the absolute value between the first proximity level and the second proximity level, and determine the initial adjustment range for adjusting the opening of the first electronic expansion valve based on the absolute value; The initial adjustment range is adjusted based on the target parameters of the indoor unit in each shutdown state to determine the final adjustment range; wherein, the target parameters include the equivalent length of the pipeline from the indoor unit to the outdoor unit; The opening degree of the first electronic expansion valve of each indoor unit in each shutdown state is adjusted based on the final adjustment range.

3. The method according to claim 2, characterized in that, The initial adjustment range is determined based on the target parameters of the indoor unit in each shutdown state to establish the final adjustment range, including: Obtain the equivalent length of the pipe from the indoor unit to the outdoor unit in each shutdown state, and determine the weight of the indoor unit in each shutdown state based on the equivalent length of the pipe, wherein the longer the equivalent length of the pipe, the greater the weight. The final adjustment range is determined by multiplying the weight by the initial adjustment range.

4. The method according to claim 1, characterized in that, Determining a first proximity level between a high-pressure value and a first preset protection value based on the first difference includes: determining the first proximity level based on the first difference and a first mapping table, wherein the first mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between the high-pressure value and the first preset protection value. Determining a second proximity level between exhaust superheat and a second preset protection value based on the second difference includes: determining the second proximity level based on the second difference and a second mapping table, wherein the second mapping table represents the mapping relationship between the difference range and the proximity level, and the larger the difference, the smaller the proximity level; the proximity level represents the degree of proximity between exhaust superheat and the second preset protection value.

5. The method according to claim 4, characterized in that, The method further includes: The mapping relationship between the first mapping table and the second mapping table is adjusted in real time based on the outdoor ambient temperature, wherein the lower the outdoor ambient temperature, the smaller the range of the difference.

6. The method according to claim 1, characterized in that, Determining whether to adjust the opening of the first electronic expansion valve based on the comparison results includes: When the first proximity level is greater than the second proximity level, increase the opening of the first electronic expansion valve; If the first proximity level is lower than the second proximity level, reduce the opening of the first electronic expansion valve; When the first proximity level is equal to the second proximity level, maintain the current opening of the first electronic expansion valve.

7. The method according to claim 6, characterized in that, The method further includes: When the first proximity level is greater than the second proximity level, and the difference between the first proximity level and the second proximity level exceeds a preset threshold, the opening of the first electronic expansion valve is increased, and the opening of the second electronic expansion valve of the indoor unit that is currently in operation is also increased.

8. An adjustment device for an electronic expansion valve in a multi-split air conditioner, characterized in that, include: The data acquisition module is used to collect the high-pressure value at the compressor discharge port and the compressor discharge temperature in the multi-split air conditioner. The first processing module is used to determine a first difference between the high pressure value and a first preset threshold. The second processing module is used to determine the exhaust superheat based on the exhaust temperature and the high pressure value, and to determine a second difference between the exhaust superheat and a second preset threshold. The third processing module is used to determine a first proximity level between the high pressure value and the first preset protection value based on the first difference, and to determine a second proximity level between the exhaust superheat and the second preset protection value based on the second difference. The fourth processing module is used to compare the first proximity level with the second proximity level, and determine whether to adjust the opening of the first electronic expansion valve based on the comparison result, so as to balance the high pressure and exhaust superheat of the multi-split unit, wherein the first electronic expansion valve is the first electronic expansion valve of the indoor unit in the multi-split unit that is in the off state.

9. A multi-split air conditioner, characterized in that, The multi-split air conditioner includes a control device, which includes a processor, a communication interface, a memory, and a communication bus. The processor, communication interface, and memory communicate with each other via the communication bus. The memory stores a computer program. The processor executes the computer program to implement the adjustment method of the electronic expansion valve in any one of claims 1-7.

10. A storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for adjusting the electronic expansion valve in the multi-split air conditioner according to any one of claims 1-7.

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