Refrigeration regulation and control method of air conditioning system and air conditioner

Abstract

The invention relates to the technical field of refrigeration equipment, in particular to a refrigeration regulation and control method of an air conditioning system and an air conditioner, and aims to solve the problem that when an existing air conditioner refrigerates, the heat exchange capacity of an air conditioner external unit in the environment becomes poor along with rising of the outer environment temperature, and then the refrigeration effect is affected. In order to achieve the purpose, the refrigeration regulation and control method comprises the steps that the external environment temperature Tao and the exhaust superheat degree of the air conditioning system are obtained; the actual supercooling degree A1 of the air conditioning system and the target supercooling degree A0 corresponding to the external environment temperature are obtained; comparing the target supercooling degree A0 with the actual supercooling degree A1; and selectively controlling the opening degree of the auxiliary electronic expansion valve based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1. Different target supercooling degrees are set according to different external environment temperatures, the actual supercooling degree is compared with the target supercooling degrees, and the opening degree of the auxiliary electronic expansion valve is controlled according to the comparison result, so that the air conditioning system achieves better supercooling, and the refrigeration effect is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration equipment, and in particular provides a refrigeration control method of an air-conditioning system and an air conditioner. Background Art

[0002] The refrigeration principle of the air-conditioning unit is that the compressor compresses the gaseous refrigerant into a high-temperature and high-pressure gas and sends it to the condenser for cooling. After cooling, it becomes a medium-temperature and high-pressure liquid refrigerant, and then enters the drying bottle for filtration and dehumidification. The medium-temperature liquid refrigerant is throttled and decompressed by the expansion valve to become a low-temperature and low-pressure gas-liquid mixture. After absorbing heat from the air, it evaporates into a gas, and then returns to the compressor to continue compression, and continues the refrigeration cycle.

[0003] When the air conditioner is cooling, as the external ring temperature increases, the heat exchange capacity of the air conditioner outdoor unit in this environment becomes worse, which in turn affects the cooling effect.

[0004] Therefore, the present invention needs to provide a new refrigeration control method of an air-conditioning system and an air conditioner to solve the above technical problems. Summary of the invention

[0005] The present invention aims to solve the above technical problem, that is, to solve the problem that when the existing air conditioner is refrigerating, as the external ring temperature increases, the heat exchange capacity of the air conditioner outdoor unit in this environment becomes poor, thereby affecting the refrigeration effect.

[0006] To this end, in a first aspect, the present invention provides a refrigeration control method for an air-conditioning system, the air-conditioning system comprising an outdoor unit, a secondary electronic expansion valve installed in the outdoor unit, and a target supercooling degree set according to different external ambient temperatures pre-stored in the air-conditioning system, the refrigeration control method comprising:

[0007] Obtain the external environment temperature Tao and exhaust superheat of the air conditioning system;

[0008] When the external environment temperature Tao is greater than a first preset temperature and the exhaust gas superheat is greater than a second preset temperature, obtaining an actual supercooling degree A1 of the air conditioning system and a target supercooling degree A0 corresponding to the external environment temperature;

[0009] Compare the target subcooling degree A0 with the actual subcooling degree A1;

[0010] Based on the comparison result between the target subcooling degree A0 and the actual subcooling degree A1, the opening degree of the sub-electronic expansion valve is selectively controlled.

[0011] When adopting the above technical solution, the present invention sets different target subcooling degrees according to different external ambient temperatures, compares the actual subcooling degree with the target subcooling degree, and controls the opening of the auxiliary electronic expansion valve according to the comparison result, so that the air-conditioning system can achieve better supercooling purpose, thereby improving the refrigeration effect of the air-conditioning system.

[0012] In a specific implementation of the refrigeration control method of the air-conditioning system, the step of "obtaining the external environment temperature Tao and the exhaust gas superheat of the air-conditioning system" further includes:

[0013] After the air conditioning system has been running for a first preset time, the external environment temperature Tao and the exhaust gas superheat of the air conditioning system are obtained.

[0014] When the above technical solution is adopted, obtaining the external environment temperature Tao and the exhaust gas superheat after the air-conditioning system has been running for a first preset time helps to obtain stable and accurate data.

[0015] In a specific implementation of the refrigeration control method of the air-conditioning system, the step of "selectively controlling the opening of the auxiliary electronic expansion valve based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1" specifically includes:

[0016] If the actual subcooling degree A1 is greater than the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to close until the opening of the auxiliary electronic expansion valve reaches the minimum opening value or the actual subcooling degree A1 is equal to the target subcooling degree A0; and / or

[0017] If the actual subcooling degree A1 is equal to the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to maintain the original opening; and / or

[0018] If the actual subcooling degree A1 is less than the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to open the valve until the opening degree of the auxiliary electronic expansion valve reaches the maximum opening value or the exhaust superheat degree is less than or equal to the third preset temperature or the actual subcooling degree A1 is equal to the target subcooling degree A0.

[0019] When the above technical solution is adopted, the actual supercooling degree A1 is greater than the target supercooling degree A0, which means that the actual supercooling degree enables the air-conditioning system to generate enough cold capacity for cooling. At this time, in order to reduce the operating cost, the auxiliary electronic expansion valve is closed to reduce the refrigerant flow rate, thereby reducing the heat exchange; the actual supercooling degree A1 is less than the target supercooling degree A0, which means that the actual supercooling degree makes it impossible for the air-conditioning system to generate enough cold capacity for cooling. At this time, the auxiliary electronic expansion valve is opened to increase the refrigerant flow rate, thereby increasing the heat exchange amount, reducing the liquid temperature in the capillary tube, and improving the cooling effect.

[0020] In the specific implementation of the refrigeration control method of the air-conditioning system, the operation of "pre-storing the target subcooling degree set according to different external ambient temperatures in the air-conditioning system" is specifically:

[0021] The following relationship between the target supercooling degree A0 and the external environment temperature Tao is pre-stored in the air conditioning system:

[0022] Tao=A0×k+b

[0023] Among them, k and b are coefficients, the value range of k is 0.5~0.7, and the value range of b is 14~17.

[0024] When the above technical solution is adopted, the target subcooling degree is obtained according to the external ambient temperature through the above relationship, the obtained target subcooling degree is compared with the actual subcooling degree, and the opening of the auxiliary electronic expansion valve is controlled according to the comparison result to meet the required refrigeration effect.

[0025] In a specific implementation of the refrigeration control method for the above air-conditioning system, when the auxiliary electronic expansion valve is opened or closed, the opening degree of the auxiliary electronic expansion valve increases or decreases successively according to a preset pulse value, and two adjacent times are separated by a first preset interval time.

[0026] When adopting the above technical solution, each time the auxiliary electronic expansion valve increases or decreases a preset pulse value, it remains unchanged within the first preset interval time, and changes again after the first preset interval time, thereby providing sufficient time for heat exchange of the liquid (refrigerant) in the capillary tube, thereby avoiding the frequent adjustment problem caused by the auxiliary electronic expansion valve continuing to open due to the mistaken assumption that the opening of the auxiliary electronic expansion valve does not meet the subcooling requirement due to insufficient heat exchange time.

[0027] In a specific implementation of the refrigeration control method of the air-conditioning system, the step of "if the actual supercooling degree A1 is greater than the target supercooling degree A0, controlling the auxiliary electronic expansion valve to close the valve" further includes:

[0028] If the actual supercooling degree A1 is greater than the target supercooling degree A0 and the duration is greater than the third preset time, the auxiliary electronic expansion valve is controlled to perform a valve closing operation.

[0029] When the above technical solution is adopted, the closing operation of the auxiliary electronic expansion valve is controlled after the actual subcooling degree A1 is greater than the target subcooling degree A0 and maintained for the third preset time, so as to avoid erroneous operation of closing the valve due to the instability of the actual subcooling degree A1 and the target subcooling degree A0.

[0030] In a specific implementation of the refrigeration control method of the air-conditioning system, the step of "if the actual supercooling degree A1 is less than the target supercooling degree A0, controlling the auxiliary electronic expansion valve to open the valve" further includes:

[0031] If the actual supercooling degree A1 is less than the target supercooling degree A0 and the duration is greater than a fourth preset time, the auxiliary electronic expansion valve is controlled to perform a valve opening operation.

[0032] When the above technical solution is adopted, the closing operation of the auxiliary electronic expansion valve is controlled after the actual subcooling degree A1 is less than the target subcooling degree A0 and maintained for the fourth preset time, so as to avoid erroneous operation of closing the valve due to the instability of the actual subcooling degree A1 and the target subcooling degree A0.

[0033] In a specific implementation of the refrigeration control method of the air-conditioning system, the step of "stopping until the exhaust gas superheat is less than or equal to the third preset temperature" further includes:

[0034] The process stops when the exhaust gas superheat degree is less than or equal to the third preset temperature and the duration is greater than the fifth preset time.

[0035] In a specific implementation of the refrigeration control method of the above-mentioned air-conditioning system, the air-conditioning system also includes an indoor unit, and the outdoor unit includes a compressor, a main electronic expansion valve, a capillary tube, an auxiliary refrigeration tube and a condenser, one end of the capillary tube is connected to the condenser, and the other end of the capillary tube is connected to the indoor unit, the main electronic expansion valve is installed on the capillary tube, one end of the auxiliary refrigeration tube is connected to the capillary tube after passing through the main electronic expansion valve, and the other end of the auxiliary refrigeration tube is connected to a gas-liquid separator, a secondary electronic expansion valve is installed on the auxiliary refrigeration tube, the gas-liquid separator is connected to the compressor, and heat exchange is performed between the auxiliary refrigeration tube and the capillary tube through a heat exchanger.

[0036] In a second aspect, the present invention further provides an air conditioner, comprising a controller, wherein the controller is configured to be able to execute the refrigeration control method of the air-conditioning system described in any one of the above technical solutions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings, in which:

[0038] Figure 1 It is a flow chart of the main steps of the refrigeration control method of the air-conditioning system provided by the present invention;

[0039] Figure 2 It is a detailed step flow chart of the refrigeration control method of the air-conditioning system provided by the present invention;

[0040] Figure 3 It is a schematic diagram of the outdoor unit of the air conditioning system.

[0041] List of reference numerals:

[0042] 1. Compressor; 2. Gas-liquid separator; 3. Main electronic expansion valve; 4. Heat exchanger; 5. Temperature sensor; 6. Auxiliary electronic expansion valve; 7. Condenser; 8. Auxiliary refrigeration pipe; 9. Capillary tube. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not used to limit the scope of protection of the present invention. Those skilled in the art can make adjustments to them as needed to adapt to specific application scenarios.

[0044] It should be noted that in the description of the present invention, the terms "upper", "lower", "inner", "outer", etc. indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of description, and do not indicate or imply that the relevant devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, ordinal numbers "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0045] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] When the existing air conditioner is cooling, as the external ring temperature increases, the heat exchange capacity of the air conditioner outdoor unit in this environment becomes poor, thereby affecting the cooling effect.

[0047] In order to solve the above technical problems, the present invention provides an air-conditioning system, which also includes an outdoor unit and an indoor unit. The outdoor unit includes a condenser 7, a heat exchanger 4, a capillary 9, a gas-liquid separator 2, a main electronic expansion valve 3 and an auxiliary refrigeration pipe 8. One end of the capillary 9 is connected to the condenser 7 of the outdoor unit, and the other end of the capillary 9 is connected to the indoor unit. The refrigerant of the outdoor unit is transported to the indoor unit through the capillary 9. The main electronic expansion valve 3 is installed on the capillary 9. One end of the auxiliary refrigeration pipe 8 is connected to the capillary 9 after passing through the main electronic expansion valve 3. The other end of the auxiliary refrigeration pipe 8 is connected to the gas-liquid separator 2. The gas-liquid separator 2 is connected to the compressor 1. The auxiliary electronic expansion valve 6 is installed on the auxiliary refrigeration pipe 8. The auxiliary refrigeration pipe 8 diverts the liquid (refrigerant) in the capillary tube 9. Part of the liquid enters the gas-liquid separator 2 through the auxiliary refrigeration pipe 8, and the other part of the liquid flows in the capillary tube 9 and is transported to the indoor unit. The auxiliary refrigeration pipe 8 and the capillary tube 9 are heat exchanged through the heat exchanger 4 to cool the capillary tube 9. The heat exchanger 4 can be a plate heat exchanger 4. The temperature of the liquid in the capillary tube 9 is detected by a temperature sensor 5. The temperature sensor 5 is installed at the position of the capillary tube 9 after heat exchange by the heat exchanger 4. The auxiliary electronic expansion valve 6 is installed at the position of the auxiliary refrigeration pipe 8 that has not passed through the heat exchanger 4 for heat exchange.

[0048] See first Figure 1 The present invention provides a refrigeration control method for an air-conditioning system, wherein the air-conditioning system pre-stores a target supercooling degree set according to different external ambient temperatures, and the refrigeration control method comprises:

[0049] S1, obtaining the external environment temperature Tao and exhaust gas superheat of the air conditioning system;

[0050] S2, when the external environment temperature Tao is greater than the first preset temperature and the exhaust gas superheat is greater than the second preset temperature, obtaining the actual supercooling degree A1 of the air conditioning system and the target supercooling degree A0 corresponding to the external environment temperature;

[0051] S3, comparing the target undercooling degree A0 with the actual undercooling degree A1;

[0052] S4, selectively controlling the opening of the auxiliary electronic expansion valve based on the comparison result between the target subcooling degree A0 and the actual subcooling degree A1;

[0053] Among them, the actual subcooling degree A1 is the difference between the saturation temperature corresponding to the high pressure and the temperature of the liquid (refrigerant) in the capillary tube;

[0054] Exhaust superheat is the difference between the compressor exhaust temperature and the saturation temperature corresponding to the high pressure.

[0055] It should be noted that, regarding the order of obtaining the external ambient temperature Tao and the exhaust superheat, both can be obtained at the same time, or the external ambient temperature Tao can be obtained first and then the exhaust superheat, or the exhaust superheat can be obtained first and then the external ambient temperature. Without departing from the basic principles of the present invention, those skilled in the art can adjust the execution order as needed; similarly, the order of obtaining the actual subcooling degree A1 and the target subcooling degree A0 can also be executed simultaneously, or one of them can be executed first and then the other.

[0056] In addition, it should be noted that the specific values ​​of the first preset temperature and the second preset temperature are not specifically limited in this application, and are flexibly designed according to the use requirements without deviating from the basic principles of the present invention. For example, the value of the first preset temperature is 20°C, and the value of the second preset temperature is 20°C.

[0057] In one embodiment, the operation of "pre-storing a target degree of subcooling set according to different external ambient temperatures in the air conditioning system" is specifically:

[0058] The following relationship between the target subcooling degree A0 and the external environment temperature Tao is pre-stored in the air conditioning system:

[0059] Tao=A0×k+b

[0060] Among them, k and b are coefficients, the value range of k is 0.5~0.7, and the value range of b is 14~17.

[0061] In the above embodiment, the target subcooling degree is obtained according to the external ambient temperature through the above relationship, the obtained target subcooling degree is compared with the actual subcooling degree, and the opening degree of the auxiliary electronic expansion valve is controlled according to the comparison result to meet the required refrigeration effect.

[0062] For example, the value of k may be, but is not limited to, 0.55, 0.6, or 0.65, and the value of b may be, but is not limited to, 14.5, 15, or 16. Taking the value of k as 0.6 and the value of b as 17 as an example, the target supercooling value is illustrated. If the external ambient temperature is 20°C, the target supercooling degree is 5°C, and if the external ambient temperature is 35°C, the target supercooling degree is 30°C.

[0063] In one embodiment, the step S1 of "obtaining the external environment temperature Tao and the exhaust gas superheat of the air conditioning system" further includes:

[0064] After the air conditioning system has been running for a first preset time, the external environment temperature Tao and the exhaust gas superheat of the air conditioning system are obtained.

[0065] In the above embodiment, obtaining the external environment temperature Tao and the exhaust gas superheat after the air conditioning system has been running for the first preset time is helpful to obtain the stability and accuracy of the data.

[0066] In one embodiment, the step S4 of “selectively controlling the opening of the auxiliary electronic expansion valve based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1” specifically includes:

[0067] S41, if the actual subcooling degree A1 is greater than the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to close the valve until the opening of the auxiliary electronic expansion valve reaches the minimum opening value or the actual subcooling degree A1 is equal to the target subcooling degree A0;

[0068] In the above steps, the actual subcooling degree A1 is greater than the target subcooling degree A0, indicating that the temperature of the liquid in the capillary tube is low, so that the air conditioning system can generate enough cooling capacity for refrigeration. At this time, in order to reduce the operating cost, the auxiliary electronic expansion valve is closed to reduce the refrigerant flow, thereby reducing the heat exchange between the heat exchanger and the liquid in the capillary tube, while also ensuring the refrigeration effect;

[0069] S42, if the actual subcooling degree A1 is equal to the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to maintain the original opening;

[0070] S43, if the actual supercooling degree A1 is less than the target supercooling degree A0, the auxiliary electronic expansion valve is controlled to open the valve until the opening degree of the auxiliary electronic expansion valve reaches the maximum opening value or the exhaust gas superheat degree is less than or equal to the third preset temperature or the actual supercooling degree A1 is equal to the target supercooling degree A0. The third preset temperature is less than the second preset temperature.

[0071] It should be noted that the specific value of the third preset temperature is not specifically limited in this application, and can be flexibly designed according to the use requirements without deviating from the basic principles of the present invention. For example, the value of the third preset temperature is 18°C.

[0072] In the above steps, the actual supercooling degree A1 is less than the target supercooling degree A0, indicating that the actual supercooling degree is not enough for the air-conditioning system to generate enough cold capacity for refrigeration. At this time, the auxiliary electronic expansion valve is opened to increase the refrigerant flow rate, thereby increasing the heat exchange rate between the heat exchanger and the liquid in the capillary tube, reducing the temperature of the liquid in the capillary tube, thereby improving the refrigeration effect.

[0073] In one embodiment, the step of “stopping until the exhaust gas superheat is less than or equal to a third preset temperature” further includes:

[0074] The process stops when the exhaust gas superheat degree is less than or equal to the third preset temperature and the duration is greater than the fifth preset time.

[0075] In the above embodiment, if the exhaust superheat is less than or equal to the third preset temperature, it is necessary to judge the duration. Only when the duration is greater than the fifth preset time will the valve opening operation of the auxiliary electronic expansion valve be controlled to stop. This has good stability and avoids frequent adjustments of the auxiliary electronic expansion valve due to misjudgment, which helps to extend the service life of the auxiliary electronic expansion valve.

[0076] In one embodiment, when the auxiliary electronic expansion valve performs a valve opening or valve closing operation, the opening degree of the auxiliary electronic expansion valve increases or decreases gradually according to a preset pulse value, and a first preset interval time is separated between two adjacent times.

[0077] In the above embodiment, each time the auxiliary electronic expansion valve increases or decreases the preset pulse value, it remains unchanged within the first preset interval time, and changes again after the first preset interval time, thereby providing sufficient time for heat exchange of the liquid (refrigerant) in the capillary tube, thereby avoiding the frequent adjustment problem caused by continuing to open the valve due to the auxiliary electronic expansion valve being mistakenly believed to not meet the supercooling requirement due to insufficient heat exchange time, which helps to extend the service life of the auxiliary electronic expansion valve.

[0078] In one embodiment, the step of “if the actual subcooling degree A1 is greater than the target subcooling degree A0, controlling the auxiliary electronic expansion valve to close the valve” further includes:

[0079] If the actual supercooling degree A1 is greater than the target supercooling degree A0 and the duration is greater than the third preset time, the auxiliary electronic expansion valve is controlled to perform a valve closing operation.

[0080] In the above embodiment, the closing operation of the auxiliary electronic expansion valve is controlled after the actual subcooling degree A1 is greater than the target subcooling degree A0 and maintained for the third preset time, so as to avoid erroneous closing operation caused by the instability of the actual subcooling degree A1 and the target subcooling degree A0.

[0081] In one embodiment, the step of “if the actual subcooling degree A1 is less than the target subcooling degree A0, controlling the auxiliary electronic expansion valve to perform a valve opening operation” further includes:

[0082] If the actual subcooling degree A1 is less than the target subcooling degree A0 and the duration is greater than a fourth preset time, the auxiliary electronic expansion valve is controlled to perform a valve opening operation.

[0083] In the above embodiment, the closing operation of the auxiliary electronic expansion valve is controlled after the actual subcooling degree A1 is less than the target subcooling degree A0 and maintained for the fourth preset time, so as to avoid erroneous closing operation caused by the instability of the actual subcooling degree A1 and the target subcooling degree A0.

[0084] In one embodiment, the step of “obtaining the external environment temperature Tao and the exhaust gas superheat of the air conditioning system” specifically includes:

[0085] The external environment temperature Tao and the exhaust gas superheat of the air conditioning system are obtained according to the second preset interval time.

[0086] In addition, it should be noted that the present invention does not specifically limit the specific values ​​of the first preset time, the second preset time, the third preset time, the fourth preset time, the fifth preset time, the first preset interval time and the second preset interval time. Without deviating from the basic principles of the present invention, the design can be flexibly based on actual usage requirements.

[0087] In a second aspect, the present invention further provides an air conditioner, comprising a controller, wherein the controller is configured to be able to execute the refrigeration control method of the air-conditioning system of any one of the above technical solutions.

[0088] In the above-mentioned various embodiments and various extended implementations, the present invention sets different target subcooling degrees according to different external ambient temperatures, compares the actual subcooling degrees with the target subcooling degrees, and controls the opening degree of the auxiliary electronic expansion valve according to the comparison results, so that the air-conditioning system can achieve better supercooling purposes, thereby improving the refrigeration effect of the air-conditioning system.

[0089] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A refrigeration control method for an air conditioning system, characterized in that: The air conditioning system includes an outdoor unit, a secondary electronic expansion valve is installed in the outdoor unit, a target supercooling degree set according to different external ambient temperatures is pre-stored in the air conditioning system, and the refrigeration control method includes: Obtain the external environment temperature Tao and exhaust superheat of the air conditioning system; When the external environment temperature Tao is greater than a first preset temperature and the exhaust gas superheat is greater than a second preset temperature, obtaining an actual supercooling degree A1 of the air conditioning system and a target supercooling degree A0 corresponding to the external environment temperature; Compare the target subcooling degree A0 with the actual subcooling degree A1; Based on the comparison result between the target subcooling degree A0 and the actual subcooling degree A1, the opening degree of the sub-electronic expansion valve is selectively controlled.

2. The refrigeration control method of the air conditioning system according to claim 1, characterized in that: The step of "obtaining the external environment temperature Tao and exhaust gas superheat of the air conditioning system" further includes: After the air conditioning system has been running for a first preset time, the external environment temperature Tao and the exhaust gas superheat of the air conditioning system are obtained.

3. The refrigeration control method of the air conditioning system according to claim 1, characterized in that: The step of "selectively controlling the opening of the auxiliary electronic expansion valve based on the comparison result of the target supercooling degree A0 and the actual supercooling degree A1" specifically includes: If the actual subcooling degree A1 is greater than the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to close until the opening of the auxiliary electronic expansion valve reaches the minimum opening value or the actual subcooling degree A1 is equal to the target subcooling degree A0; and / or If the actual subcooling degree A1 is equal to the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to maintain the original opening; and / or If the actual subcooling degree A1 is less than the target subcooling degree A0, the auxiliary electronic expansion valve is controlled to open the valve until the opening degree of the auxiliary electronic expansion valve reaches the maximum opening value or the exhaust superheat degree is less than or equal to the third preset temperature or the actual subcooling degree A1 is equal to the target subcooling degree A0.

4. The refrigeration control method of the air conditioning system according to claim 1, characterized in that: The operation of "the target subcooling degree set according to different external ambient temperatures is pre-stored in the air conditioning system" is specifically: The following relationship between the target supercooling degree A0 and the external environment temperature Tao is pre-stored in the air conditioning system: Tao=A0×k+b Among them, k and b are coefficients, the value range of k is 0.5~0.7, and the value range of b is 14~17.

5. The refrigeration control method of the air conditioning system according to claim 3, characterized in that: When the auxiliary electronic expansion valve performs a valve opening or valve closing operation, the opening degree of the auxiliary electronic expansion valve increases or decreases gradually according to a preset pulse value, and a first preset interval time is separated between two adjacent times.

6. The refrigeration control method of the air conditioning system according to claim 3, characterized in that: The step of "if the actual subcooling degree A1 is greater than the target subcooling degree A0, controlling the auxiliary electronic expansion valve to perform a valve closing operation" further includes: If the actual supercooling degree A1 is greater than the target supercooling degree A0 and the duration is greater than the third preset time, the auxiliary electronic expansion valve is controlled to perform a valve closing operation.

7. The refrigeration control method of the air conditioning system according to claim 3, characterized in that: The step of "if the actual subcooling degree A1 is less than the target subcooling degree A0, controlling the auxiliary electronic expansion valve to perform a valve opening operation" further includes: If the actual supercooling degree A1 is less than the target supercooling degree A0 and the duration is greater than a fourth preset time, the auxiliary electronic expansion valve is controlled to perform a valve opening operation.

8. The refrigeration control method of the air conditioning system according to claim 3, characterized in that: The step of "stopping until the exhaust gas superheat is less than or equal to the third preset temperature" further includes: The process stops when the exhaust gas superheat degree is less than or equal to the third preset temperature and the duration is greater than the fifth preset time.

9. The refrigeration control method of an air-conditioning system according to any one of claims 1 to 8, characterized in that: The air-conditioning system also includes an indoor unit, and the outdoor unit includes a compressor, a main electronic expansion valve, a capillary tube, an auxiliary refrigeration tube and a condenser, one end of the capillary tube is connected to the condenser, and the other end of the capillary tube is connected to the indoor unit, the main electronic expansion valve is installed on the capillary tube, one end of the auxiliary refrigeration tube is connected to the capillary tube after passing through the main electronic expansion valve, and the other end of the auxiliary refrigeration tube is connected to a gas-liquid separator, a secondary electronic expansion valve is installed on the auxiliary refrigeration tube, the gas-liquid separator is connected to the compressor, and heat exchange is performed between the auxiliary refrigeration tube and the capillary tube through a heat exchanger.

10. An air conditioner, comprising a controller, characterized in that: The controller is configured to be able to execute the refrigeration control method of the air-conditioning system according to any one of claims 1 to 9.

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