Liquid level control method, air conditioning system and nonvolatile computer readable storage medium

Abstract

The invention discloses a liquid level control method, an air conditioning system and a nonvolatile computer readable storage medium. The method is applied to the air conditioning system, the air conditioning system comprises an evaporator, a compressor and an electronic expansion valve, and the method comprises the steps that the target exhaust superheat degree is determined according to operation parameters of the compressor; and based on the target exhaust superheat degree and the current exhaust superheat degree, the opening degree of an electronic expansion valve is adjusted, so that the adjusted actual exhaust superheat degree of the compressor is matched with the target exhaust superheat degree, and the opening degree of the electronic expansion valve corresponds to the liquid level of the evaporator. Therefore, the air conditioning system can control the liquid level of the evaporator and ensure that the liquid level of the evaporator is within the preset liquid level interval, so that the reliability of the compressor is improved, the reliability of the air conditioning system is improved, meanwhile, the heat exchange pipe of the evaporator can be fully utilized, and the heat exchange efficiency of the evaporator is improved. Therefore, the performance and the reliability of the air conditioning system can be considered at the same time.

Description

Technical Field

[0001] The present application relates to the technical field of air-conditioning systems, and more specifically, to a liquid level control method, an air-conditioning system, and a non-volatile computer-readable storage medium. Background Art

[0002] With the development of air-conditioning systems, there are more and more types of evaporators. For example, evaporators are gradually upgraded from dry type to flooded type and falling film type evaporators, thereby improving the energy efficiency of the whole product. For flooded evaporators, the liquid level of the refrigerant in the evaporator will affect the efficiency and reliability of the system. If the liquid level is too high, the compressor will easily inhale more liquid refrigerant, resulting in reduced reliability, while if the liquid level is too low, the heat exchange efficiency will decrease, resulting in lower performance of the air-conditioning system. Therefore, how to ensure that the liquid level of the evaporator is kept within a reasonable range so that the air-conditioning system can take into account both performance and reliability has become an urgent problem to be solved. Summary of the invention

[0003] Embodiments of the present application provide a liquid level control method, an air conditioning system, and a non-volatile computer-readable storage medium.

[0004] The liquid level control method of the embodiment of the present application is applied to an air-conditioning system, which includes an evaporator, a compressor and an electronic expansion valve. The method includes: determining a target exhaust superheat according to the operating parameters of the compressor; adjusting the opening of the electronic expansion valve based on the target exhaust superheat and the current exhaust superheat, so that the actual exhaust superheat of the compressor after adjustment matches the target exhaust superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

[0005] The air conditioning system of the embodiment of the present application includes a processor, a memory and a computer program, wherein the computer program is stored in the memory and executed by the processor, and the computer program includes instructions for executing a liquid level control method. The liquid level control method is applied to an air conditioning system, the air conditioning system includes an evaporator, a compressor and an electronic expansion valve, and the method includes: determining a target exhaust gas superheat according to the operating parameters of the compressor; adjusting the opening of the electronic expansion valve based on the target exhaust gas superheat and the current exhaust gas superheat so that the adjusted actual exhaust gas superheat of the compressor matches the target exhaust gas superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

[0006] The non-volatile computer-readable storage medium of the embodiment of the present application includes a computer program, and when the computer program is executed by a processor, the processor executes a liquid level control method. The liquid level control method is applied to an air conditioning system, and the air conditioning system includes an evaporator, a compressor, and an electronic expansion valve. The method includes: determining a target exhaust gas superheat according to the operating parameters of the compressor; adjusting the opening of the electronic expansion valve based on the target exhaust gas superheat and the current exhaust gas superheat so that the actual exhaust gas superheat of the compressor after adjustment matches the target exhaust gas superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

[0007] The liquid level control method, air conditioning system and non-volatile computer-readable storage medium of the embodiment of the present application determine the target exhaust superheat that meets the current working conditions according to the operating parameters of the compressor. When the current exhaust superheat of the compressor matches the target exhaust superheat, the liquid level of the evaporator is within a reasonable range. The opening of the electronic expansion valve corresponds to the liquid level of the evaporator. The larger the opening of the electronic expansion valve, the higher the liquid level of the evaporator. Therefore, the air conditioning system can adjust the opening of the electronic expansion valve based on the current exhaust superheat and the target exhaust superheat to adjust the liquid level of the evaporator so that the actual exhaust superheat of the adjusted compressor matches the target exhaust superheat. It can be understood that when the current exhaust superheat matches the target exhaust superheat, the liquid level of the evaporator is within a reasonable range. In this way, the air-conditioning system can control the liquid level of the evaporator, ensuring that when the liquid level of the evaporator is too high or too low, the opening of the electronic expansion valve can be adjusted in time to make the liquid level of the evaporator return to the preset liquid level range, so as to ensure that the compressor will not inhale a large amount of liquid refrigerant for a long time, thereby improving the reliability of the compressor and thus the reliability of the air-conditioning system. At the same time, it can also ensure that the heat exchange tubes of the evaporator are fully utilized, thereby improving the heat exchange efficiency of the evaporator and thus improving the performance of the air-conditioning system. In this way, the air-conditioning system can take into account both performance and reliability.

[0008] Additional aspects and advantages of the embodiments of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the embodiments of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0010] Figure 1 It is a schematic diagram of an application scenario of a liquid level control method in certain embodiments of the present application;

[0011] Figure 2 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0012] Figure 3 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0013] Figure 4 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0014] Figure 5 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0015] Figure 6 is a schematic diagram of a scenario of a liquid level control method according to certain embodiments of the present application;

[0016] Figure 7 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0017] Figure 8 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0018] Fig. 9 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0019] Fig.10 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0020] Fig.11 is a flow chart of a liquid level control method according to certain embodiments of the present application;

[0021] Fig.12 is a schematic diagram of a module of a liquid level control device according to certain embodiments of the present application;

[0022] Fig.13 is a schematic diagram of the structure of an air conditioning system according to certain embodiments of the present application;

[0023] Fig.14 It is a schematic diagram of the connection status of a non-volatile computer-readable storage medium and a processor in certain embodiments of the present application. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions from beginning to end. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of the present application, and cannot be understood as limiting the embodiments of the present application.

[0025] The following first introduces an application scenario of the technical solution of this application. Figure 1As shown, the control method provided by the present application can be applied to the air conditioning system 100. At the same time, the air conditioning system 100 achieves comfortable adjustment of the indoor environment by accurately controlling the circulation and distribution of the refrigerant. Among them, the refrigerant, commonly known as refrigerant, is a working fluid used in the air conditioning system to transfer heat energy and produce a refrigeration effect.

[0026] The air conditioning system 100 may include an evaporator 20, a compressor 30, an electronic expansion valve 40 and a condenser 50. The two ends of the evaporator 20 are connected to the compressor 30 and the electronic expansion valve 40 respectively, and the electronic expansion valve 40 is arranged between the condenser 50 and the evaporator 20. The compressor 30 is a core component of the air conditioning system 100. After the low-temperature and low-pressure refrigerant is compressed and heated, it becomes a high-temperature and high-pressure gas to achieve the cooling or heating function. The refrigerant output by the compressor 30 flows into the condenser 50. The condenser 50 converts the high-temperature and high-pressure refrigerant into a low-temperature and low-pressure state, and releases heat to the surrounding environment. The refrigerant output by the condenser 50 flows into the evaporator 20 through the electronic expansion valve 40. The electronic expansion valve 40 can be used to control the flow of the refrigerant flowing from the condenser 50 to the evaporator 20, so that the liquid level of the evaporator 20 can be controlled by the electronic expansion valve 40. The evaporator 20 uses the characteristic that the liquid low-temperature refrigerant is easy to evaporate under low pressure to absorb the heat of the cooled medium, thereby achieving the purpose of cooling. Finally, the refrigerant output from the evaporator 20 flows into the compressor 30 .

[0027] Among them, the evaporator 20 can be a full-liquid evaporator, the evaporator runs water in the heat exchange tube of the evaporator 20, and the refrigerant evaporates outside the heat exchange tube, which can be understood as the heat exchange tube is immersed in the refrigerant. When the liquid level of the refrigerant in the evaporator 20 is too high or too low, it will affect the heat exchange efficiency and reliability of the evaporator 20. When the liquid level of the evaporator 20 is too high, the compressor 30 is easy to inhale liquid refrigerant, which makes it very easy for the compressor 30 to be wet compressed, resulting in damage to the compressor 30. When the liquid level of the evaporator 20 is too low, a large number of heat exchange pipes inside the evaporator 20 are exposed outside the refrigerant, which reduces the effective utilization rate of the heat exchange area of ​​the evaporator 20, resulting in a decrease in the heat exchange efficiency of the evaporator 20, thereby causing a decrease in the performance of the air-conditioning system 100.

[0028] As energy-saving products are constantly being innovated and energy efficiency requirements are constantly upgraded, efficient air-conditioning systems must first gradually develop and improve efficient heat exchange and efficient components. For example, in the case of central air-conditioning products, taking the current central air-conditioning products as chillers, the evaporator is gradually upgraded from dry to full liquid and falling film evaporators, thereby improving the energy efficiency of the entire product.

[0029] At present, the control methods for full-liquid or falling-film evaporators provided by equipment manufacturers include exhaust superheat control method, small temperature difference control method and liquid level meter control method. However, the reliability and performance of the air-conditioning systems using these control methods cannot be taken into account at the same time, so that they sacrifice performance while ensuring reliability, and lack consideration for system safety while ensuring performance.

[0030] Specifically, when the air conditioning system uses the exhaust superheat to control the liquid level of the evaporator, the air conditioning system controls the opening of the electronic expansion valve according to the exhaust superheat and the exhaust superheat target value, but the target value at this time is a fixed value, and the corresponding exhaust superheat is different when the evaporator liquid level is within a reasonable range under different working conditions. Therefore, the fixed exhaust superheat target value cannot be adapted to a variety of working conditions, so that under different working conditions, after controlling the opening of the electronic expansion valve according to the same exhaust superheat target value, it is difficult to ensure that the liquid level of the evaporator under each working condition is within a reasonable range, thereby failing to ensure the performance and reliability of the air conditioning system.

[0031] When the air-conditioning system adopts a small temperature difference for control, although it can ensure good heat exchange efficiency, under some working conditions, the changes in the exhaust superheat of the compressor and the water temperature setting value will lead to the risk of wet compression of the compressor, and long-term operation will cause the compressor to burn out.

[0032] For the liquid level meter control method, the air conditioning system controls the electronic expansion valve according to the liquid level sensor detection value and the target value. However, as the air conditioning system operates at different water temperatures, the refrigerant "porosity" inside the evaporator is different. When the water temperature setting value is set too high, the high water temperature increases the heat exchange of the refrigerant, the refrigerant boils violently, and the compressor is prone to wet compression, resulting in compressor damage. In addition, the use of the liquid level meter will also increase the cost of the air conditioning system and reduce the cost performance of the air conditioning system.

[0033] In order to solve the above technical problems, the embodiment of the present application provides a liquid level control method, which will be described in detail below:

[0034] See also Figure 2 The embodiment of the present application provides a liquid level control method, which is applied to an air conditioning system. The air conditioning system includes an evaporator, a compressor and an electronic expansion valve. The liquid level control method includes:

[0035] Step 01: Determine the target exhaust superheat according to the operating parameters of the compressor;

[0036] Specifically, the current exhaust superheat of the compressor can be used to reflect the current liquid level of the evaporator. When the current liquid level of the evaporator is low, the refrigerant is easily in an overheated state, resulting in a high exhaust superheat of the compressor. Therefore, the air conditioning system can judge the liquid level of the evaporator based on the exhaust superheat of the compressor, so as to control the liquid level of the evaporator accordingly.

[0037] Under different working conditions, when the liquid level of the evaporator is within a reasonable range, the exhaust superheat of the compressor may be different. The air conditioning system can determine the reasonable range of the liquid level according to the structure of the evaporator, that is, determine the preset liquid level interval. Then, the current working condition can be determined according to the current operating parameters of the compressor to determine the corresponding exhaust superheat when the liquid level of the evaporator is within the preset liquid level interval under the current working condition, thereby obtaining the target exhaust superheat. For example, the mapping relationship between the operating parameters of the compressor and the target exhaust superheat under different working conditions can be pre-set, and then the target exhaust superheat corresponding to the current operating parameters of the compressor can be determined according to the mapping relationship. It can be understood that the accuracy of the target exhaust superheat obtained at this time is higher.

[0038] Step 02: Based on the target exhaust superheat and the current exhaust superheat, adjust the opening of the electronic expansion valve so that the actual exhaust superheat of the adjusted compressor matches the target exhaust superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

[0039] Specifically, the air conditioning system can control the liquid level of the evaporator by controlling the opening of the electronic expansion valve. The larger the opening of the electronic expansion valve, the greater the flow of the refrigerant flowing into the evaporator, and the higher the liquid level of the evaporator. After determining the target exhaust superheat, the air conditioning system can determine the opening of the electronic expansion valve based on the current exhaust superheat and the target exhaust superheat, and control the electronic expansion valve according to the determined opening to adjust the liquid level of the evaporator, so that the liquid level of the evaporator gradually reaches the preset liquid level range, and then the actual exhaust superheat after the liquid level adjustment matches the target exhaust superheat.

[0040] For example, the air conditioning system can determine whether the current exhaust superheat is too high or too low based on the current exhaust superheat and the target exhaust superheat, so as to determine whether the current liquid level is too high or too low, so as to adjust the opening of the electronic expansion valve. In the case where the current exhaust superheat is too high, the air conditioning system can determine that the current liquid level is too low, and the opening of the electronic expansion valve can be increased. In the case where the current exhaust superheat is too low, the air conditioning system can determine that the current liquid level is too high, and the opening of the electronic expansion valve can be reduced. In the case where the current superheat is moderate, the air conditioning system can determine that the current liquid level is in the preset liquid level range, and the opening of the electronic expansion valve can be maintained unchanged.

[0041] After such adjustment, the air-conditioning system can make the actual exhaust superheat match the target exhaust superheat, and since the target exhaust superheat matches the preset liquid level range under the current operating conditions, the adjusted evaporator liquid level can be within the preset liquid level range, so that the air-conditioning system can avoid the problem of low reliability caused by the evaporator liquid level being too high, and can also avoid the problem of low heat exchange efficiency caused by the evaporator liquid level being too low, thereby allowing the air-conditioning system to take into account both reliability and performance.

[0042] The liquid level control method of the embodiment of the present application determines the target exhaust superheat that meets the current working conditions according to the operating parameters of the compressor. When the current exhaust superheat of the compressor matches the target exhaust superheat, the liquid level of the evaporator is within a reasonable range. The opening of the electronic expansion valve corresponds to the liquid level of the evaporator. The larger the opening of the electronic expansion valve, the higher the liquid level of the evaporator. Therefore, the air-conditioning system can adjust the opening of the electronic expansion valve based on the current exhaust superheat and the target exhaust superheat to adjust the liquid level of the evaporator so that the actual exhaust superheat of the adjusted compressor matches the target exhaust superheat. It can be understood that when the actual exhaust superheat matches the target exhaust superheat, the liquid level of the evaporator is within a reasonable range. In this way, the air-conditioning system can control the liquid level of the evaporator, ensuring that when the liquid level of the evaporator is too high or too low, the opening of the electronic expansion valve can be adjusted in time to make the liquid level of the evaporator return to the preset liquid level range, so as to ensure that the compressor will not inhale a large amount of liquid refrigerant for a long time, thereby improving the reliability of the compressor and thus the reliability of the air-conditioning system. At the same time, it can also ensure that the heat exchange tubes of the evaporator are fully utilized, thereby improving the heat exchange efficiency of the evaporator and thus improving the performance of the air-conditioning system. In this way, the air-conditioning system can take into account both performance and reliability.

[0043] At the same time, the present application can achieve the effect of liquid level control without the need for an additional liquid level meter, so that compared with the solution using a liquid level meter, the present application can reduce the manufacturing cost of the air-conditioning system while taking into account performance and reliability.

[0044] See also Figure 3 In some embodiments, step 01: determining a target exhaust gas superheat according to operating parameters of the compressor, comprises:

[0045] Step 011: obtaining the operating parameters of the compressor and the current exhaust superheat when the liquid level of the evaporator is in a preset liquid level area under multiple different working conditions, so as to form multiple sets of fitting data, each set of fitting data including the operating parameters and the current exhaust superheat corresponding to the same working condition;

[0046] Step 012: determining a mapping function between target exhaust superheat and operating parameters according to multiple sets of fitting data;

[0047] Step 013: Determine the target exhaust gas superheat according to the mapping function and the operating parameters of the compressor.

[0048] Specifically, the air conditioning system can pre-set the mapping relationship between the operating parameters of the compressor and the target exhaust superheat under different working conditions. The air conditioning system first obtains the operating parameters of the compressor and the current exhaust superheat when the liquid level of the evaporator is in a preset liquid level range under multiple different working conditions. The operating parameters and current exhaust superheat corresponding to each working condition constitute a set of fitting data. It can be understood that multiple sets of fitting data can be generated at this time.

[0049] Then the air conditioning system is fitted according to multiple sets of fitting data to obtain a mapping function between the target exhaust superheat and the operating parameters. For example, the operating parameters of the compressor include the suction saturation temperature TE, the exhaust saturation temperature TC and the load Q of the compressor. At this time, the air conditioning system can obtain the following mapping function according to the suction saturation temperature, exhaust saturation temperature, load and current exhaust superheat under multiple working conditions:

[0050] DSH_tar=(a1*TE^2+b1*TE+c1)*(a2*TC^2+b2*TC+c2)+(a3*Q^2+b3*Q+c3) (1)

[0051] Among them, DSH_tar is the target exhaust superheat, a1, a2, a3, b1, b2, b3, c1, c2 and c3 are all fitting coefficients, which are not limited here.

[0052] The air conditioning system can then determine the target exhaust superheat according to the mapping function and the operating parameters of the compressor. For example, the air conditioning system can bring the current suction saturation temperature, exhaust saturation temperature and load of the compressor into the above formula (1) to obtain a target exhaust superheat that matches the current operating conditions.

[0053] In this way, the air-conditioning system can determine the accurate mapping relationship between the operating parameters of the compressor and the target exhaust superheat under different working conditions based on multiple sets of fitting data, so that the air-conditioning system can determine the target exhaust superheat that matches the current working conditions based on the current operating parameters of the compressor, thereby ensuring that after the subsequent air-conditioning system adjusts the opening of the electronic expansion valve according to the target exhaust superheat, the liquid level of the evaporator can reach the preset liquid level range, thereby ensuring that the air-conditioning system can take into account both reliability and performance.

[0054] See also Figure 4 In some embodiments, the operating parameters of the compressor include suction saturation temperature, exhaust saturation temperature and current load, and the liquid level control method includes:

[0055] Step 03: Determine the target evaporation pressure based on the outlet water temperature of the evaporator before the compressor is started;

[0056] Step 01: Determine the target exhaust superheat according to the operating parameters of the compressor, including:

[0057] Step 014: Determine the target exhaust superheat according to the suction saturation temperature, the exhaust saturation temperature and the current load;

[0058] Step 02: Based on the target exhaust superheat and the current exhaust superheat, adjust the opening of the electronic expansion valve, including:

[0059] Step 021: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat;

[0060] Step 022: Adjust the opening of the electronic expansion valve according to the target evaporation pressure.

[0061] Specifically, the evaporation pressure of the evaporator can reflect the liquid level of the evaporator. The greater the evaporation pressure, the higher the liquid level of the evaporator. Therefore, the air conditioning system can control the opening of the electronic expansion valve according to the target evaporation pressure of the evaporator to control the liquid level of the evaporator.

[0062] Since the load and outlet water temperature of the compressor affect the boiling of the refrigerant, the air conditioning system can calculate the initial target evaporation pressure of the evaporator before the compressor is started according to the outlet water temperature of the evaporator before the compressor is started, so as to ensure that the liquid level of the evaporator is in the preset liquid level range when the compressor is started, thereby avoiding the phenomenon of liquid carrying when the compressor is started. For example, the air conditioning system can set a temperature sensor at the outlet of the evaporator to obtain the outlet water temperature LWT, and then determine the initial target evaporation pressure according to the outlet water temperature. At this time, the mapping function between the outlet water temperature and the target evaporation pressure can be obtained by fitting according to multiple sets of related data. For example, the air conditioning system can fit according to multiple sets of outlet water temperatures and current evaporation pressures when the liquid level of the evaporator is in the preset liquid level range, and obtain the mapping relationship between the outlet water pressure and the initial target evaporation pressure, so that the initial target evaporation pressure meets the current working conditions, so that after the opening of the electronic expansion valve is controlled according to the target evaporation pressure, the liquid level of the evaporator can be in the preset liquid level range, thereby ensuring that the phenomenon of liquid carrying does not occur when the compressor is started.

[0063] For example, the mapping relationship obtained by fitting is as follows:

[0064] SP_INI=-a*LWT^2+b*LWT+c (2)

[0065] Among them, SP_INI is the initial target evaporation pressure, that is, a, b, and c in the formula are coefficients obtained by fitting, and are not limited here.

[0066] In this way, the air-conditioning system can determine the initial target evaporation pressure according to the outlet water temperature, so that the air-conditioning system is suitable for application scenarios with low outlet water temperature in comfort occasions, and can also be suitable for application scenarios with high water temperature in data centers, making the air-conditioning system have a wide range of applications and strong applicability.

[0067] After the compressor is started, the air conditioning system can obtain the current suction saturation temperature, exhaust saturation temperature and current load of the compressor, wherein the suction saturation temperature can be calculated based on the suction port pressure of the compressor, the exhaust saturation temperature can be calculated based on the discharge port pressure of the compressor, and the current load can be determined based on the suction saturation pressure, the exhaust saturation temperature and the operating current of the compressor. Then the air conditioning system can determine the target exhaust superheat according to the suction saturation temperature, the exhaust saturation temperature and the current load to ensure that the target exhaust superheat is adapted to the current working condition, for example, the target exhaust superheat is determined using the above formula (1).

[0068] Next, the air conditioning system adjusts the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat to ensure that the target evaporation pressure is adapted to the current operating conditions, wherein the current exhaust superheat can be determined according to the current exhaust temperature and the exhaust saturation temperature.

[0069] For example, when the exhaust superheat is too high according to the target exhaust superheat, the air conditioning system can determine that the current liquid level of the evaporator is low, and the target evaporation pressure set at this time is low, so the target evaporation pressure needs to be increased. When the exhaust superheat is too low according to the target exhaust superheat, the air conditioning system can determine that the current liquid level of the evaporator is high, and the target evaporation pressure set at this time is high, so the target evaporation pressure needs to be reduced. When the exhaust superheat is moderate according to the target exhaust superheat, the air conditioning system can determine that the current liquid level of the evaporator is in the preset liquid level range, and the target evaporation pressure set at this time is appropriate, so there is no need to adjust the target evaporation pressure, or the adjustment value can be determined to be 0.

[0070] Finally, the air-conditioning system can control the opening of the electronic expansion valve according to the target evaporating pressure, so that the actual evaporating pressure of the adjusted evaporator is adapted to the target evaporating pressure, and the adjusted actual exhaust superheat is matched with the target exhaust superheat. Therefore, after adjusting the opening of the electronic expansion valve, the liquid level of the evaporator can reach the preset liquid level range, and the performance of the evaporator can be optimized, thereby ensuring that the air-conditioning system can take into account both reliability and performance.

[0071] See also Figure 5 In some embodiments, step 021: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat, comprises:

[0072] Step 0211: determining a target superheat range according to the current exhaust superheat;

[0073] Step 0212: determining a first correction value according to the target superheat range and the current exhaust superheat;

[0074] Step 0213: Adjust the target evaporation pressure according to the first correction value and the current target evaporation pressure.

[0075] Specifically, the air conditioning system can determine the target superheat interval according to the target exhaust superheat, for example, the target exhaust superheat is set as the minimum value of the target superheat interval, and the sum of the target exhaust superheat and the preset value is set as the maximum value of the target superheat interval, such as the target superheat interval is [DSH_tar, DSH_tar+1]. The target superheat interval corresponds to the preset liquid level interval. When the current exhaust superheat is in the target superheat interval, the liquid level of the evaporator is in the preset liquid level interval.

[0076] The air conditioning system may then determine a first correction value according to the target superheat range and the current exhaust gas superheat, so as to adjust the target evaporation pressure according to the first correction value and the current target evaporation pressure.

[0077] When the current exhaust gas superheat is greater than the maximum value of the target superheat interval, the air conditioning system can determine that the current exhaust gas superheat is too large and the liquid level of the evaporator is too low, then it is necessary to increase the target evaporation pressure to increase the opening of the electronic expansion valve, thereby increasing the liquid level of the evaporator. Therefore, the first correction value is a positive value at this time.

[0078] In some embodiments, the specific value of the first correction value can be determined according to the difference between the current exhaust superheat and the maximum value of the target superheat interval. In this case, multiple difference intervals can be set for the case where the current exhaust superheat is greater than the maximum value of the target superheat interval, and different difference intervals correspond to different specific values ​​of the first correction value. For example, please combine Figure 6 , DSH is the current exhaust superheat, the target superheat interval is [DSH_tar, DSH_tar+1], and SP_tar is the target evaporation pressure. When the difference between the current exhaust superheat and the maximum value of the target superheat interval is in the difference interval [0, 1], that is, DHS_tar+2≥DSH>DHS_tar+1, the first correction value is +1. When the difference between the current exhaust superheat and the maximum value of the target superheat interval is in the difference interval [1, 2], that is, DHS_tar+3≥DSH>DHS_tar+2, the first correction value is +2. When the difference between the current exhaust superheat and the maximum value of the target superheat interval is in the difference interval [2, +∞], that is, DSH>DHS_tar+3, the first correction value is +3. Of course, the air conditioning system can also preset a mapping function between the difference between the current exhaust superheat and the maximum value of the target superheat interval and the first correction value, and determine the first correction value according to the mapping function.

[0079] When the current exhaust gas superheat is less than the minimum value of the target superheat interval, the air conditioning system can determine that the current exhaust gas superheat is too low and the liquid level of the evaporator is too high, then it is necessary to reduce the target evaporation pressure to reduce the opening of the electronic expansion valve, thereby reducing the liquid level of the evaporator. Therefore, the first correction value is a negative value at this time.

[0080] In some embodiments, the specific value of the first correction value can be determined according to the difference between the current exhaust superheat and the minimum value of the target superheat interval. In this case, multiple difference intervals can be set for the case where the current exhaust superheat is less than the minimum value of the target superheat interval, and different difference intervals correspond to different specific values ​​of the first correction value. For example Figure 6 When the difference between the current exhaust superheat and the minimum value of the target superheat interval is in the difference interval [0, 1], that is, DHS_tar-1≤DSH<DHS_tar, the first correction value is -1; when the difference between the current exhaust superheat and the minimum value of the target superheat interval is in the difference interval [1, 2], that is, DHS_tar-2≤DSH<DHS_tar-1, the first correction value is -2; when the difference between the current exhaust superheat and the minimum value of the target superheat interval is in the difference interval [2, +∞], DSH<DHS_tar-2, the first correction value is -3. Of course, the air conditioning system can also preset a mapping function between the difference between the current exhaust superheat and the minimum value of the target superheat interval and the first correction value, and determine the first correction value according to the mapping function.

[0081] When the current exhaust superheat is within the target superheat range, the air conditioning system can determine that the current exhaust superheat is moderate and the liquid level of the evaporator is within the preset liquid level range. In this case, there is no need to adjust the target evaporation pressure and the first correction value is 0.

[0082] After determining the first correction value, the air conditioning system may adjust the target evaporation pressure according to the first correction value and the current target evaporation pressure, for example, taking the sum of the first correction value and the current target evaporation pressure as the adjusted target evaporation pressure.

[0083] In this way, the air-conditioning system can accurately determine the first correction value according to the target superheat range and the current exhaust superheat, so that after the air-conditioning system controls the opening of the electronic expansion valve according to the adjusted target evaporation pressure, the liquid level of the evaporator can reach the preset liquid level range, thereby ensuring that the air-conditioning system can take into account both reliability and performance.

[0084] Of course, the air conditioning system may not determine the target superheat range, and directly determine the first correction value based on the relationship between the current exhaust superheat and the target exhaust superheat. When the current exhaust superheat is equal to the target exhaust superheat, the first correction value is 0, when the current exhaust superheat is greater than the target exhaust superheat, the first correction value is a positive value, and when the current exhaust superheat is less than the target exhaust superheat, the first correction value is a negative value. The specific value of the first correction value can be determined based on the difference between the current exhaust superheat and the target exhaust superheat. In this way, the air conditioning system can also accurately obtain the corresponding first correction value based on the current exhaust superheat and the target exhaust superheat, so that the target evaporation pressure is adjusted according to the first correction value. After the air conditioning system controls the opening of the electronic expansion valve according to the target evaporation pressure, the liquid level of the evaporator reaches the preset liquid level range.

[0085] See also Figure 7 In some embodiments, step 0213: adjusting the target evaporation pressure according to the first correction value and the current target evaporation pressure includes:

[0086] Step 02131: When the sum of the first correction value and the current target evaporation pressure is greater than the maximum value of the preset pressure interval, the target evaporation pressure is adjusted to the maximum value of the preset pressure interval;

[0087] Step 02132: When the sum of the first correction value and the current target evaporation pressure is less than the minimum value of the preset pressure interval, the target evaporation pressure is adjusted to the minimum value of the preset pressure interval;

[0088] Step 02133: When the sum of the first correction value and the current target evaporation pressure is within the preset pressure range, the target evaporation pressure is adjusted to the sum of the first correction value and the current target evaporation pressure.

[0089] Specifically, the air conditioning system can set a preset pressure interval according to the design characteristics of the evaporator, and the target evaporation pressure is adjusted within the preset pressure interval. When the target evaporation pressure is within the preset pressure interval, the evaporator can be ensured to operate normally. The air conditioning system adjusts the target evaporation pressure according to the sum of the first correction value and the current target evaporation pressure.

[0090] In the case where the sum of the first correction value and the current target evaporation pressure is greater than the maximum value of the preset pressure interval, the air conditioning system may determine that the sum of the first correction value and the current target evaporation pressure exceeds the preset pressure interval. At this time, if the sum of the first correction value and the current target evaporation pressure is used as the adjusted target evaporation pressure and the opening of the electronic expansion valve is adjusted, the evaporator may not operate normally. Therefore, at this time, the air conditioning system adjusts the target evaporation pressure to the maximum value of the preset pressure interval to ensure that the target evaporation pressure does not exceed the preset pressure interval.

[0091] In the case where the sum of the first correction value and the current target evaporation pressure is less than the minimum value of the preset pressure interval, the air conditioning system may determine that the sum of the first correction value and the current target evaporation pressure exceeds the preset pressure interval. At this time, if the sum of the first correction value and the current target evaporation pressure is used as the adjusted target evaporation pressure and the opening of the electronic expansion valve is adjusted, the evaporator may not operate normally. Therefore, at this time, the air conditioning system adjusts the target evaporation pressure to the minimum value of the preset pressure interval to ensure that the target evaporation pressure does not exceed the preset pressure interval.

[0092] When the sum of the first correction value and the current target evaporation pressure is within the preset pressure range, the target evaporation pressure can be adjusted directly according to the sum of the first correction value and the current target evaporation pressure, that is, the target evaporation pressure is adjusted to the sum of the first correction value and the current target evaporation pressure.

[0093] In this way, the air conditioning system can adjust the target evaporation pressure within the preset pressure range to ensure that the target evaporation pressure does not exceed the preset pressure range, thereby ensuring that the evaporator can operate normally. At the same time, the target evaporation pressure can also be adjusted in real time according to the first correction value to ensure that after the opening of the electronic expansion valve is adjusted according to the adjusted target evaporation pressure, the liquid level of the evaporator is within the preset liquid level range.

[0094] See also Figure 8 In some embodiments, step 021: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat, comprises:

[0095] Step 0214: When the duration of the current exhaust gas superheat being outside the target superheat interval is greater than a first preset duration, the target evaporation pressure is adjusted according to the current exhaust gas superheat and the target exhaust gas superheat.

[0096] Specifically, the first preset time duration is the maximum duration that the current exhaust gas superheat is outside the target superheat range when the performance and reliability of the air-conditioning system are within a reasonable range. For example, the first preset time duration is 30 seconds or 1 minute. If the duration exceeds the first preset time duration, the performance and reliability of the air-conditioning system will be greatly affected.

[0097] The air conditioning system can time during operation to record the duration of time that the current exhaust gas superheat is outside the target superheat interval. When the duration of time that the current exhaust gas superheat is outside the target superheat interval is greater than a first preset duration, the air conditioning system can determine that the performance and reliability of the air conditioning system will be affected. In this case, the target evaporation pressure needs to be adjusted according to the current exhaust gas superheat and the target exhaust gas superheat, and the liquid level of the evaporator needs to be adjusted in time to improve the performance and reliability of the air conditioning system.

[0098] When the duration during which the current exhaust superheat is outside the target superheat interval is less than the first preset duration, it can be considered that the performance and reliability of the air-conditioning system are still within a reasonable range. Therefore, the air-conditioning system does not need to adjust the liquid level of the evaporator. At this time, there is no need to adjust the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat.

[0099] In this way, the air-conditioning system will only adjust the target evaporating pressure when the current exhaust superheat is outside the range of the target superheat interval for a period longer than the first preset time period, so as to ensure that the air-conditioning system will not adjust the target evaporating pressure too frequently, thereby ensuring the smooth operation of the evaporator; on the other hand, it can ensure that when the current exhaust superheat is outside the range of the target superheat interval for a period longer than the first preset time period, the air-conditioning system can timely adjust the target evaporating pressure and timely adjust the liquid level of the evaporator, thereby ensuring that the performance and reliability of the air-conditioning system are high.

[0100] See also Fig. 9 In some embodiments, the liquid level control method further comprises:

[0101] Step 04: Determine the current load of the compressor according to the suction saturation temperature, exhaust saturation temperature and operating current of the compressor;

[0102] Step 021: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat, further comprising:

[0103] Step 0215: Determine a second correction value according to the current load;

[0104] Step 0216: Adjust the target evaporation pressure according to the second correction value, the current exhaust superheat and the target exhaust superheat.

[0105] Specifically, when the load of the compressor is different, the suction volume of the compressor is different, and the impact on the evaporation of the refrigerant is also different. For example, the higher the load of the compressor, the greater the suction volume, and the more violently the refrigerant in the evaporator boils. At this time, the liquid level of the evaporator can be lowered to prevent the compressor from sucking in more liquid refrigerant when the refrigerant boils violently. For another example, the suction volume of the compressor is reduced under low load, and the boiling inside the evaporator is relatively weakened, which may cause the heat exchange tubes inside the evaporator to be exposed to the refrigerant, thereby reducing the effective utilization rate of the heat exchange area of ​​the evaporator, which will cause the evaporation temperature to drop by 0.2℃~0.5℃.

[0106] Therefore, the air conditioning system can determine the current load of the compressor according to the suction saturation temperature, exhaust saturation temperature and operating current of the compressor, wherein the operating current of the compressor can be obtained according to the current detected by the compressor mutual inductor. The mapping relationship between the suction saturation temperature, exhaust saturation temperature, operating current and compressor can also be fitted in advance, so that the current load of the compressor can be accurately determined according to the mapping relationship later.

[0107] Then, the second correction value may be determined according to the current load, for example, according to the following formula:

[0108] SP(Q)=A*(100-Q) (3)

[0109] Wherein, Q is the current load, SP(Q) is the second correction value, the formula is a formula obtained by fitting in advance, and A is the coefficient obtained by fitting.

[0110] Then the air conditioning system can adjust the target evaporation pressure according to the second correction value, the current exhaust gas superheat and the target exhaust gas superheat. For example, the air conditioning system can determine the first correction value according to the current exhaust gas superheat and the target exhaust gas superheat, and at this time, the sum of the first correction value, the second correction value and the current target evaporation pressure can be used as the adjusted target evaporation pressure.

[0111] In this way, the air-conditioning system adds the factor of the compressor load when determining the target evaporating pressure, so that the target evaporating pressure also matches the current load of the compressor, thereby ensuring that under different compressor loads, the liquid level of the evaporator can be located in the preset liquid level range, thereby facilitating improving the reliability and performance of the air-conditioning system.

[0112] See also Fig.10 In some embodiments, the liquid level control method further comprises:

[0113] Step 05: Determine the saturation temperature of the electronic expansion valve according to the valve inlet pressure of the electronic expansion valve, so as to determine the current degree of subcooling according to the saturation temperature;

[0114] Step 021: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat, further comprising:

[0115] Step 0217: determining a third correction value according to the current supercooling degree and a preset supercooling degree threshold;

[0116] Step 0218: Adjust the target evaporation pressure according to the third correction value, the current exhaust superheat and the target exhaust superheat.

[0117] Specifically, if the refrigerant before the electronic expansion valve has no supercooling, it will affect the heat exchange efficiency of the air conditioning system. When the air conditioning system is under partial load, the supercooling is small. Due to the existence of pipeline resistance, the air conditioning system is very likely to have the phenomenon of electronic expansion valve flashing, which will not only cause unstable control of the air conditioning system, but also greatly affect the performance of the air conditioning system. If the electronic expansion valve flashes, the efficiency of the air conditioning system will be affected by at least 3%.

[0118] For example, refrigerants without subcooling include gas refrigerants and liquid refrigerants. At this time, the refrigerant will have a gas cross-talk phenomenon when passing through the electronic expansion valve, so that when the refrigerant enters the evaporator, it may contain more bubbles or gas, which will reduce the effective evaporation amount of the refrigerant in the evaporator, thereby reducing the cooling efficiency of the system. Therefore, the air conditioning system can correct the target evaporation pressure according to the subcooling degree.

[0119] First, a preset supercooling threshold is set according to the supercooling of the refrigerant corresponding to the electronic expansion valve when the cross-flow phenomenon does not occur. Then, the air conditioning system can obtain the pre-valve pressure of the electronic expansion valve to determine the saturation temperature of the electronic expansion valve according to the pre-valve pressure of the electronic expansion valve, and obtain the pre-valve temperature of the electronic expansion valve according to the temperature sensor. The difference between the saturation temperature of the electronic expansion valve and the pre-valve temperature is the current supercooling. Then, the air conditioning system can determine the third correction value according to the current supercooling and the preset supercooling threshold.

[0120] For example, when the current supercooling degree is greater than or equal to the preset supercooling degree threshold, the air conditioning system can confirm that the third correction value is 0. When the current supercooling degree is less than the preset supercooling degree threshold, the third correction value can be a preset fixed value, such as -0.2, which can be determined according to the influence of the liquid level of the evaporator on the supercooling degree. Alternatively, the air conditioning system can also obtain the mapping relationship between the difference between the current supercooling degree threshold and the preset supercooling degree threshold and the third correction value through pre-fitting, and determine the third correction value according to the mapping relationship and the difference between the current supercooling degree threshold and the preset supercooling degree threshold.

[0121] After obtaining the third correction value, the air conditioning system can adjust the target evaporation pressure according to the third correction value, the current exhaust superheat and the target exhaust superheat. For example, the air conditioning system can determine the first correction value according to the current exhaust superheat and the target exhaust superheat, and at this time, the sum of the first correction value, the third correction value and the current target evaporation pressure can be used as the adjusted target evaporation pressure.

[0122] In this way, the factor of subcooling is added when determining the target evaporating pressure, so that the target evaporating pressure also matches the subcooling, thereby ensuring that after the air-conditioning system controls the liquid level of the evaporator according to the target evaporating pressure, the refrigerant has a certain degree of subcooling, thereby facilitating improving the heat exchange efficiency of the air-conditioning system, and then facilitating improving the performance of the air-conditioning system.

[0123] Of course, when adjusting the target evaporation pressure, the air conditioning system can simultaneously consider the exhaust gas superheat, subcooling and actual load of the compressor, that is, the first correction value, the second correction value, the third correction value and the current target evaporation pressure are used as the adjusted target evaporation pressure. In this way, after the air conditioning system adjusts the opening of the electronic expansion valve according to the adjusted target evaporation pressure, the current exhaust gas superheat, minimum subcooling and actual load of the compressor of the air conditioning system can be within a safe range, so as to improve the heat exchange efficiency and reliability of the evaporator of the air conditioning system under any working conditions.

[0124] See also Fig.11 In some embodiments, step 0217: determining a third correction value according to the current supercooling degree and a preset supercooling degree threshold value includes:

[0125] Step 02171: When the duration that the current supercooling degree is less than the preset supercooling degree threshold value is greater than a second preset duration, a third correction value is determined according to the current supercooling degree and the preset supercooling degree threshold value.

[0126] Specifically, the second preset time is the maximum duration of the duration that the current supercooling degree is less than the preset supercooling degree threshold value when the heat exchange efficiency of the air-conditioning system is within a reasonable range, for example, the second preset time is 30s, 60s or 90s. If the duration exceeds the second preset time, the heat exchange efficiency of the air-conditioning system will be greatly affected.

[0127] The air conditioning system can time during operation to record the duration of the current supercooling degree being less than the preset supercooling degree threshold. When the duration of the current supercooling degree being less than the preset supercooling degree threshold is greater than the second preset duration, the air conditioning system can determine that the heat exchange efficiency will be affected at this time, and then it is necessary to determine the third correction value according to the current supercooling degree and the preset supercooling degree threshold, so as to timely adjust the liquid level of the evaporator, increase the supercooling degree of the refrigerant, and thus improve the heat exchange efficiency of the air conditioning system.

[0128] When the duration that the current supercooling degree is less than the preset supercooling degree threshold is less than the second preset duration, the air-conditioning system may consider that the heat exchange efficiency at this time is still within a reasonable range, and therefore the liquid level of the evaporator may not be adjusted, and the third correction value is 0 at this time.

[0129] In this way, the air-conditioning system will only adjust the target evaporating pressure when the current supercooling degree is less than the preset supercooling threshold value for a period longer than a second preset period. On the one hand, it ensures that the air-conditioning system will not adjust the target evaporating pressure too frequently, thereby ensuring the smooth operation of the evaporator. On the other hand, it ensures that when the current supercooling degree is less than the preset supercooling threshold value for a period shorter than the second preset period, the air-conditioning system can timely adjust the target evaporating pressure and the liquid level of the evaporator to increase the supercooling degree of the refrigerant, thereby ensuring the heat exchange efficiency of the air-conditioning system.

[0130] See also Fig.12 In order to better implement the liquid level control method of the embodiment of the present application, the embodiment of the present application also provides a liquid level control device 10. The liquid level control device 10 may include a first determination module 11 and an adjustment module 12. The first determination module 11 is used to determine the target exhaust gas superheat according to the operating parameters of the compressor. The adjustment module 12 is used to adjust the opening of the electronic expansion valve based on the target exhaust gas superheat and the current exhaust gas superheat, so that the actual exhaust gas superheat of the adjusted compressor matches the target exhaust gas superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

[0131] The first determination module 11 is specifically used to obtain the operating parameters of the compressor and the current exhaust superheat when the liquid level of the evaporator is in a preset liquid level area under multiple different operating conditions, so as to form multiple sets of fitting data, each set of fitting data includes the operating parameters and the current exhaust superheat corresponding to the same operating conditions; determine the mapping function between the target exhaust superheat and the operating parameters according to the multiple sets of fitting data; determine the target exhaust superheat according to the mapping function and the operating parameters of the compressor.

[0132] The liquid level control device 10 further includes a second determination module 13, which is used to determine the target evaporation pressure according to the outlet water temperature of the evaporator before the compressor is started. The first determination module 11 is specifically used to determine the target exhaust superheat according to the suction saturation temperature, the exhaust saturation temperature and the current load. The adjustment module 12 is specifically used to adjust the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat; and adjust the opening of the electronic expansion valve according to the target evaporation pressure.

[0133] The adjustment module 12 is specifically used to determine a target superheat interval according to the current exhaust superheat; determine a first correction value according to the target superheat interval and the current exhaust superheat; and adjust the target evaporation pressure according to the first correction value and the current target evaporation pressure.

[0134] The adjustment module 12 is specifically used to adjust the target evaporation pressure to the maximum value of the preset pressure interval when the sum of the first correction value and the current target evaporation pressure is greater than the maximum value of the preset pressure interval; to adjust the target evaporation pressure to the minimum value of the preset pressure interval when the sum of the first correction value and the current target evaporation pressure is less than the minimum value of the preset pressure interval; and to adjust the target evaporation pressure to the sum of the first correction value and the current target evaporation pressure when the sum of the first correction value and the current target evaporation pressure is within the range of the preset pressure interval.

[0135] The adjustment module 12 is specifically configured to adjust the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat when the duration of the current exhaust superheat being outside the target superheat interval is greater than a first preset duration.

[0136] The liquid level control device 10 further includes a third determination module 14, which is used to determine the current load of the compressor according to the suction saturation temperature, exhaust saturation temperature and operating current of the compressor. The adjustment module 12 is specifically used to determine the second correction value according to the current load; and adjust the target evaporation pressure according to the second correction value, the current exhaust superheat and the target exhaust superheat.

[0137] The liquid level control device 10 further includes a fourth determination module 15, which is used to determine the saturation temperature of the electronic expansion valve according to the valve inlet pressure of the electronic expansion valve, so as to determine the current supercooling degree according to the saturation temperature. The adjustment module 12 is used to determine a third correction value according to the current supercooling degree and a preset supercooling degree threshold value; and adjust the target evaporation pressure according to the third correction value, the current exhaust gas superheat degree and the target exhaust gas superheat degree.

[0138] The adjustment module 12 is specifically configured to determine a third correction value according to the current supercooling degree and the preset supercooling degree threshold value when the duration that the current supercooling degree is less than the preset supercooling degree threshold value is greater than a second preset duration.

[0139] The liquid level control device 10 is described above from the perspective of functional modules in conjunction with the accompanying drawings. The functional modules can be implemented in hardware form, can be implemented in software form, or can be implemented in combination with hardware and software modules. Specifically, the steps of the method embodiments in the embodiments of the present application can be completed by hardware integrated logic circuits in the processor and / or software form instructions. The steps of the method disclosed in the embodiments of the present application can be directly embodied as a hardware coding processor, or can be executed by a combination of hardware and software modules in the coding processor. Optionally, the software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps in the above method embodiments in combination with its hardware.

[0140] See also Fig.13 The air conditioning system 100 of the embodiment of the present application includes a processor 60, a memory 70 and a computer program, wherein the computer program is stored in the memory 70 and executed by the processor 60, and the computer program includes instructions for executing the liquid level control method of any of the above-mentioned embodiments.

[0141] See also Fig.14 The embodiment of the present application also provides a computer-readable storage medium 300 on which a computer program 310 is stored. When the computer program 310 is executed by a processor 320, the steps of the liquid level control method of any of the above-mentioned embodiments are implemented. For the sake of brevity, they are not repeated here.

[0142] In the description of this specification, the descriptions with reference to the terms "certain embodiments", "in an example", "exemplarily", etc., mean that the specific features, structures, materials or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0143] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code that includes one or more executable instructions for implementing the steps of a specific logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0144] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A liquid level control method, characterized in that: Applied to an air conditioning system, the air conditioning system includes an evaporator, a compressor and an electronic expansion valve, and the method includes: determining a target exhaust gas superheat according to operating parameters of the compressor; Based on the target exhaust superheat and the current exhaust superheat, the opening of the electronic expansion valve is adjusted so that the adjusted actual exhaust superheat of the compressor matches the target exhaust superheat, and the opening of the electronic expansion valve corresponds to the liquid level of the evaporator.

2. The liquid level control method according to claim 1, characterized in that: Determining the target exhaust gas superheat according to the operating parameters of the compressor includes: Acquire the operating parameters and current exhaust gas superheat of the compressor when the liquid level of the evaporator is in a preset liquid level area under multiple different working conditions to form multiple sets of fitting data, each set of fitting data includes the operating parameters and current exhaust gas superheat corresponding to the same working condition; Determining a mapping function between the target exhaust superheat and the operating parameters according to a plurality of sets of fitting data; The target exhaust gas superheat is determined according to the mapping function and the operating parameters of the compressor.

3. The liquid level control method according to claim 1, characterized in that: The operating parameters of the compressor include suction saturation temperature, exhaust saturation temperature and current load. The method further includes: determining a target evaporation pressure according to the outlet water temperature of the evaporator before starting the compressor; Determining a target exhaust gas superheat according to the operating parameters of the compressor includes: determining a target exhaust superheat according to the intake saturation temperature, the exhaust saturation temperature and the current load; The adjusting the opening of the electronic expansion valve based on the target exhaust gas superheat and the current exhaust gas superheat comprises: adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat; The opening degree of the electronic expansion valve is adjusted according to the target evaporation pressure.

4. The liquid level control method according to claim 3, characterized in that: The adjusting the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat comprises: Determine the target superheat range based on the current exhaust superheat; determining a first correction value according to the target superheat range and the current exhaust superheat; The target evaporation pressure is adjusted according to the first correction value and the current target evaporation pressure.

5. The liquid level control method according to claim 3, characterized in that: The adjusting the target evaporation pressure according to the current exhaust superheat and the target exhaust superheat comprises: When the duration of the current exhaust superheat being outside the target superheat interval is greater than a first preset duration, the target evaporation pressure is adjusted according to the current exhaust superheat and the target exhaust superheat.

6. The liquid level control method according to claim 3, characterized in that: Also includes: determining a current load of the compressor according to the suction saturation temperature, the exhaust saturation temperature and the operating current of the compressor; The adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat also includes: determining a second correction value according to the current load; The target evaporation pressure is adjusted according to the second correction value, the current exhaust superheat and the target exhaust superheat.

7. The liquid level control method according to claim 3, characterized in that: Also includes: Determining the saturation temperature of the electronic expansion valve according to the valve inlet pressure of the electronic expansion valve, so as to determine the current degree of subcooling according to the saturation temperature; The adjusting the target evaporation pressure according to the current exhaust gas superheat and the target exhaust gas superheat also includes: determining a third correction value according to the current supercooling degree and a preset supercooling degree threshold; The target evaporation pressure is adjusted according to the third correction value, the current exhaust superheat and the target exhaust superheat.

8. The liquid level control method according to claim 7, characterized in that: The determining of the third correction value according to the current supercooling degree and a preset supercooling degree threshold value comprises: In a case where the duration for which the current degree of supercooling is less than the preset degree of supercooling threshold is greater than a second preset duration, a third correction value is determined according to the current degree of supercooling and the preset degree of supercooling threshold.

9. An air conditioning system, characterized in that: include: Processor, memory; and A computer program, wherein the computer program is stored in the memory and executed by the processor, and the computer program includes instructions for executing the liquid level control method according to any one of claims 1 to 8.

10. A non-volatile computer-readable storage medium containing a computer program, wherein when the computer program is executed by a processor, the processor executes the liquid level control method according to any one of claims 1 to 8.

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