Frequency conversion air conditioner control method and system with low temperature refrigeration function

Abstract

The present invention discloses a control method and system for a variable frequency air conditioner with a low-temperature refrigeration function, the method comprising: controlling the variable frequency air conditioner to switch between a normal temperature refrigeration mode and a low-temperature refrigeration mode according to the ambient temperature; in the low-temperature refrigeration mode, comprising a first adjustment method and a second adjustment method; the first adjustment method comprising: gradually lowering the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature; increasing the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature; the second adjustment method comprising: when the system high pressure is lower than the current pressure operating range of the compressor, on the basis of the current target evaporation temperature, lowering the target evaporation temperature, and at the same time, maintaining the current speed of the fan unchanged; through the above method, the refrigeration function of the variable frequency air conditioner in a low-temperature environment can be realized, and at the same time, the low-temperature refrigeration mode can be entered without stopping during operation, and the working stability is high, which can effectively reduce the indoor ambient temperature fluctuation.

Description

Technical Field

[0001] The present invention relates to the technical field of air-conditioning refrigeration regulation and control, and in particular to a variable frequency air-conditioning control method and system with a low-temperature refrigeration function. Background Art

[0002] Low temperature air conditioning system is an air conditioning system with a temperature range of -15℃~15℃, relative humidity of 40%~70%, and certain air conditioning accuracy requirements. Many process manufacturing processes or storage of goods require a low temperature air conditioning environment, which is different from conventional comfort or process air conditioning, and also different from general cold storage.

[0003] When the air conditioner is running in cooling mode under low ambient temperature (the national standard stipulates that the ambient temperature for conventional air conditioning cooling is 20℃~35℃, and temperatures below this are considered low-temperature cooling), the condensing pressure will drop significantly, and the refrigerant pressure passing through the throttling element will also drop. This is because the pressure drop ratio of the general throttling element is fixed, or adjusted in a small range, so the refrigerant pressure in the evaporator will also drop accordingly, and the evaporation temperature will drop. It can be seen that the regulation and control of the air conditioner for low-temperature cooling is significantly different from the normal temperature cooling mode (also called high-temperature cooling).

[0004] At present, air conditioners generally use the following solutions to achieve low-temperature refrigeration function:

[0005] 1. Use the outdoor ambient temperature sensor to determine whether the ambient temperature has entered the low-temperature cooling mode. When the system enters the cooling mode, calculate the system subcooling degree and adjust the outdoor unit fan gear according to the subcooling degree. This requires that the coupling control of the system subcooling degree, ambient temperature and fan gear is very accurate. Therefore, during use, the control accuracy is often not ideal, resulting in poor working stability of the air conditioner in the low-temperature cooling mode and large indoor temperature fluctuations;

[0006] 2. Use an outdoor condenser to add a heat insulation device. By stopping the fan, use the heat insulation device to use part of the system heat to insulate the gas-liquid separator and the system to maintain stable operation of the system. This method has a high equipment cost.

[0007] 3. Use multiple four-way valves and multiple independent condensers, switch the area of ​​the condenser through valves, control the condensation effect of the refrigerant in the condenser, and achieve stable operation of the machine in a low-temperature environment. This method will also significantly increase the cost of equipment. Summary of the invention

[0008] The object of the present invention is to provide a variable frequency air conditioner control method and system with a low temperature refrigeration function, which can effectively ensure the working stability of the air conditioner in a low temperature refrigeration mode and save equipment costs.

[0009] In order to achieve the above object, the present invention discloses a variable frequency air conditioner control method with low temperature refrigeration function, which comprises:

[0010] Acquiring the ambient temperature of the environment where the compressor is located outdoors, and controlling the variable frequency air conditioner to switch between a normal temperature cooling mode and a low temperature cooling mode according to the ambient temperature;

[0011] In the low-temperature refrigeration mode, the operating state of the compressor is regulated and controlled by a first regulating method, and the operating state of the fan in the outdoor unit is regulated and controlled by a second regulating method;

[0012] The first adjustment method comprises:

[0013] gradually lowering the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature;

[0014] increasing the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature;

[0015] The second adjustment method comprises:

[0016] When the fan is in a loaded state or a deloaded state, obtaining a current system high pressure at the exhaust port of the compressor;

[0017] When the system high pressure is lower than the currently allowed pressure operating range of the compressor, the target evaporation temperature is lowered based on the current target evaporation temperature, and at the same time, the current speed of the fan is maintained unchanged.

[0018] Preferably, the second adjustment method for lowering the target evaporation temperature includes:

[0019] When the system high pressure is lower than the pressure operation range, the target evaporation temperature is adjusted downward at preset time intervals until the number of downward adjustments reaches a preset value or the target evaporation temperature reaches a minimum limit value;

[0020] When the system high pressure is within the pressure operating range of the compressor, the target evaporating temperature is increased at preset time intervals until the target evaporating temperature is adjusted back to an initial value when the variable frequency air conditioner enters the low temperature cooling mode.

[0021] Preferably, in the low-temperature refrigeration mode, the working state of the electronic expansion valve located in the indoor unit of the variable frequency air conditioner is further adjusted by a third adjustment method, and the third adjustment method includes:

[0022] Controlling the opening of the electronic expansion valve to be halved to obtain the initial opening of the electronic expansion valve, and causing the electronic expansion valve to enter an initial stage of a preset time length;

[0023] In the initial stage, when the system low pressure of the compressor is lower than a preset value, the opening of the electronic expansion valve is increased based on the initial opening;

[0024] After the initial stage is over, the opening of the electronic expansion valve is adjusted in real time according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor.

[0025] Preferably, it is determined at a preset time interval whether the temperature at the outlet of the indoor unit coil is lower than a preset freezing point, and if so, the current opening of the electronic expansion valve is reduced.

[0026] The present invention also discloses a variable frequency air conditioning control system with a low temperature refrigeration function, which comprises:

[0027] A mode switching unit, which is used to control the variable frequency air conditioner to switch between a normal temperature cooling mode and a low temperature cooling mode according to the ambient temperature;

[0028] A first regulating unit and a second regulating unit provided in the low temperature refrigeration mode;

[0029] The first regulating unit is used to regulate and control the operating state of the compressor in the variable frequency air conditioner, and includes an evaporation temperature regulating module and a compressor regulating module;

[0030] The evaporation temperature adjustment module is used to gradually lower the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature;

[0031] The compressor adjustment module is used to increase the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature;

[0032] The second regulating unit is used to regulate and control the operating state of the fan located in the outdoor unit, and includes a high-voltage monitoring module and a fan regulating module;

[0033] The high pressure monitoring module is used to obtain the current system high pressure at the exhaust port of the compressor when the fan is in a loaded state or a unloaded state;

[0034] The fan adjustment module is used to lower the target evaporation temperature based on the current target evaporation temperature when the system high pressure is lower than the currently allowed pressure operating range of the compressor, while maintaining the current speed of the fan unchanged.

[0035] Preferably, the evaporation temperature adjustment module includes an upward adjustment module and a downward adjustment module;

[0036] The downward adjustment module is used to adjust the target evaporation temperature downward at a preset time interval when the system high pressure is lower than the pressure operation range, until the number of downward adjustments reaches a preset value or the target evaporation temperature reaches a minimum limit value;

[0037] The downward adjustment module is used to increase the target evaporating temperature at a preset time interval when the system high pressure is within the pressure operating range of the compressor, until the target evaporating temperature is adjusted back to the initial value when the variable frequency air conditioner enters the low-temperature cooling mode.

[0038] Preferably, in the low temperature mode, a third regulating unit for regulating the working state of the electronic expansion valve located in the indoor unit of the variable frequency air conditioner is further provided, and the third regulating unit includes an initial regulating module and a continuous regulating module;

[0039] The initial adjustment module is used to control the opening of the electronic expansion valve to be halved when the variable frequency air conditioner initially enters the low temperature mode, so as to obtain the initial opening of the electronic expansion valve, and to make the electronic expansion valve enter the initial stage of a preset time length, and in the initial stage, when the system low pressure of the compressor is lower than a preset value, the opening of the electronic expansion valve is expanded on the basis of the initial opening;

[0040] The continuous adjustment module is used to adjust the opening of the electronic expansion valve in real time according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor after the initial stage ends.

[0041] Preferably, the continuous adjustment module further determines whether the temperature at the outlet of the indoor unit coil is lower than a preset freezing point at a preset time interval, and if so, reduces the current opening of the electronic expansion valve.

[0042] The present invention also discloses another variable frequency air conditioning control system, which comprises:

[0043] one or more processors;

[0044] Memory;

[0045] and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the programs include instructions for executing the variable frequency air conditioning control method as described above.

[0046] The present invention also discloses a computer-readable storage medium, which includes a computer program. The computer program can be executed by a processor to implement the variable frequency air conditioner control method as described above.

[0047] Compared with the prior art, in the above technical scheme of the present invention, the variable frequency air conditioner determines whether to enter the low-temperature refrigeration mode by the ambient temperature of the environment where the compressor is located outdoors. When entering the low-temperature refrigeration mode, the operation of the compressor is adjusted and controlled by the first adjustment method, so that the compressor outputs refrigeration power in the low-temperature environment. In addition, the operation of the fan in the outdoor unit is adjusted and controlled by the second adjustment method, so as to avoid frequent adjustment of the compressor near the working point. It can be seen that through the above technical scheme, the refrigeration function of the variable frequency air conditioner in a low-temperature environment can be realized, and the low-temperature refrigeration mode can be entered without stopping during operation, and the working stability is high, which can effectively reduce the indoor environmental temperature fluctuation. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The figure is a flow chart of the variable frequency air conditioner control method in an embodiment of the present invention.

[0049] Figure 2 for Figure 1 Flow chart of the first adjustment method.

[0050] Figure 3 for Figure 1 Flow chart of the second adjustment method.

[0051] Figure 4 for Figure 2 Flow chart of the method for lowering the target evaporation temperature.

[0052] Figure 5 for Figure 1 Flowchart of the third adjustment method.

[0053] Figure 6 for Figure 1 The third adjustment method is further implemented in the flow chart. DETAILED DESCRIPTION

[0054] In order to explain the technical content, structural features, achieved objectives and effects of the present invention in detail, the following is a detailed description in conjunction with the implementation methods and the accompanying drawings.

[0055] This embodiment discloses a method for controlling a variable frequency air conditioner with a low temperature refrigeration function, so as to adjust and control a variable frequency air conditioner with a normal temperature refrigeration mode and a low temperature refrigeration mode, so that the variable frequency air conditioner can freely switch between the normal temperature refrigeration mode and the low temperature refrigeration mode.

[0056] like Figure 1 The variable frequency air conditioning control method in this embodiment includes the following steps:

[0057] S1: Obtaining the ambient temperature of the environment where the compressor is located outdoors through a temperature sensor;

[0058] S2: Control the variable frequency air conditioner to switch between the normal temperature cooling mode and the low temperature cooling mode according to the ambient temperature, that is, determine whether the ambient temperature is lower than a preset threshold (such as zero degrees), if yes, execute S3, if not, execute S4;

[0059] S3: Controlling the variable frequency air conditioner to enter a low temperature refrigeration mode, in which the operation state of the compressor is regulated and controlled by a first regulation method, and the operation state of the fan in the outdoor unit is regulated and controlled by a second regulation method;

[0060] S4: Control the inverter air conditioner to enter the normal temperature cooling mode.

[0061] In the above step S3, if Figure 2 , the first adjustment method includes:

[0062] S310: gradually lowering the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature;

[0063] S311: Increasing the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature. For a variable frequency compressor, the higher the operating frequency of the compressor, the lower the corresponding real-time evaporation temperature. Therefore, the current evaporation temperature is reduced by increasing the operating frequency of the compressor to make it close to the target evaporation temperature.

[0064] In the above step S3, if Figure 3 , the second adjustment method includes:

[0065] S320: When the fan is in a loaded state or a deloaded state, obtaining a current system high pressure at the exhaust port of the compressor, where the system high pressure refers to the exhaust pressure after oil separation in the compressor;

[0066] S321: When the system high pressure is lower than the currently allowed pressure operating range of the compressor, the target evaporation temperature is lowered based on the current target evaporation temperature, and at the same time, the current speed of the fan is maintained unchanged.

[0067] It should be noted that for the outdoor fan in the variable frequency air conditioner, corresponding to the system high pressure of the compressor at different stages, the fan has four working states, namely loading state, maintenance state, load reduction state and shutdown state. In the loading state, the fan increases the frequency until the maximum speed; in the maintenance state, the fan maintains the current speed unchanged; in the load reduction state, the fan decreases the frequency until the minimum speed; in the shutdown state, the fan stops rotating.

[0068] In the above step S321, the reason for maintaining the current speed of the fan unchanged is that when the compressor exceeds the rated operating range, the evaporation temperature reduction mechanism will be triggered, causing the compressor to be loaded. If the fan does not maintain the current speed, the high pressure change of the system will cause the fan to frequently increase and decrease load. Because the control has a certain inertia, too frequent adjustment will make the pressure change of the compressor system complicated, which is not conducive to orderly adjustment, and the compressor system will become extremely unstable.

[0069] Further, in the above step S310, if Figure 4 The second adjustment method for lowering the target evaporation temperature includes the following steps:

[0070] S3100: Determine whether the system high pressure is lower than the pressure operating range of the compressor. If not, execute step S3101; if yes, execute step S3102. It should be noted that for the compressor system of the variable frequency air conditioner, since it has high pressure protection, the system high pressure will not exceed the rated high pressure.

[0071] S3101: Raise the target evaporating temperature at preset time intervals, for example, by 2°C every 5 minutes, until the target evaporating temperature is adjusted back to the initial value when the variable frequency air conditioner enters the low-temperature cooling mode; for another example, if the current target evaporating temperature has been lowered four times, each time by 2°C, for a total of 8°C, then in this step, the maximum adjustment is 8°C, that is, the target evaporating temperature is adjusted back to the starting time of entering the low-temperature cooling mode;

[0072] S3102: Determine whether the time interval from the last downward adjustment of the target evaporation temperature reaches a preset value, if not, return to step S3100, if yes, execute step S3103;

[0073] S3103: Determine whether the number of downward adjustments reaches a preset value or whether the target evaporation temperature reaches a minimum limit value. If yes, return to step S3100; if no, execute step S3104;

[0074] S3104: Lower the current target evaporation temperature by a gradient (eg, 2°C).

[0075] In the process of adjusting the working frequency of the compressor, in order to further cooperate with the stable operation of the compressor, in the above step S3, the working state of the electronic expansion valve located in the indoor unit of the variable frequency air conditioner is also adjusted by the third adjustment method, such as Figure 5 , the third adjustment method includes:

[0076] S330: controlling the opening of the electronic expansion valve to be halved to obtain an initial opening of the electronic expansion valve, and causing the electronic expansion valve to enter an initial stage of a preset time length;

[0077] S331: Whether the initial stage time is over, if not, proceed to S332, if yes, proceed to S334;

[0078] S332: Determine whether the system low pressure of the compressor is lower than a preset value, if yes, proceed to S333, if no, return to S331;

[0079] S333: increasing the opening of the electronic expansion valve based on the initial opening;

[0080] S334: The opening of the electronic expansion valve is adjusted in real time according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor to ensure that the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor are within a normal range.

[0081] Furthermore, if Figure 6 , the third adjustment method comprises the following steps:

[0082] S335: Whether the preset interval time is reached, if yes, proceed to S336, if no, return to S335;

[0083] S336: Is the temperature at the outlet of the indoor unit coil lower than the preset freezing point? If yes, proceed to S337; if no, clear the interval time and return to S334;

[0084] S337: Reduce the current opening of the electronic expansion valve to avoid ice formation at the outlet of the indoor unit coil, and return to S334.

[0085] In summary, the control method of the present invention is that the variable frequency air conditioner determines whether to enter the low temperature refrigeration mode by the ambient temperature of the environment where the compressor is located outdoors. When entering the low temperature refrigeration mode, the operation of the compressor is regulated and controlled by the first adjustment method, so that the compressor outputs refrigeration power in a low temperature environment. In addition, the operation of the fan in the outdoor unit is regulated and controlled by the second adjustment method, and the operation of the electronic expansion valve located in the indoor unit is regulated and controlled by the third adjustment method, so as to avoid frequent adjustment of the compressor near the working point. The above control method can realize the refrigeration function of the variable frequency air conditioner in a low temperature environment, and its operating temperature range is between -15℃ and 15℃. At the same time, it can enter the low temperature refrigeration mode without stopping during operation, and has high working stability, which can effectively reduce the indoor environment temperature fluctuation. In addition, the control method in the embodiment of the present invention can be used for both a single-machine variable frequency air conditioning system and a multi-split variable frequency air conditioning system.

[0086] The present invention also discloses a variable frequency air conditioning control system, which comprises:

[0087] A mode switching unit, which is used to control the variable frequency air conditioner to switch between a normal temperature cooling mode and a low temperature cooling mode according to the ambient temperature;

[0088] A first regulating unit and a second regulating unit arranged in a low temperature refrigeration mode;

[0089] The first regulating unit is used to regulate and control the operating state of the compressor in the variable frequency air conditioner, including an evaporation temperature regulating module and a compressor regulating module;

[0090] The evaporation temperature adjustment module is used to gradually lower the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature;

[0091] A compressor adjustment module, used to increase the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature;

[0092] The second regulating unit is used to regulate and control the operating state of the fan in the outdoor unit, including a high-voltage monitoring module and a fan regulating module;

[0093] A high pressure monitoring module is used to obtain the current system high pressure at the compressor exhaust port when the fan is in a loaded state or a reduced load state;

[0094] The fan adjustment module is used to lower the target evaporation temperature based on the current target evaporation temperature when the system high pressure is lower than the current allowable pressure operating range of the compressor, while maintaining the current fan speed unchanged.

[0095] Further, the evaporation temperature adjustment module includes an upward adjustment module and a downward adjustment module;

[0096] A downward adjustment module is used to adjust the target evaporation temperature downward at a preset time interval when the system high pressure is lower than the pressure operation range, until the number of downward adjustments reaches a preset value or the target evaporation temperature reaches a minimum limit value;

[0097] The downward adjustment module is used to increase the target evaporating temperature at a preset time interval when the system high pressure is within the pressure operating range of the compressor, until the target evaporating temperature is adjusted back to the initial value when the variable frequency air conditioner enters the low-temperature cooling mode.

[0098] Furthermore, in the low temperature mode, a third regulating unit is provided for regulating the working state of the electronic expansion valve located in the indoor unit of the variable frequency air conditioner, and the third regulating unit includes an initial regulating module and a continuous regulating module;

[0099] An initial adjustment module is used to control the opening of the electronic expansion valve to be halved when the variable frequency air conditioner initially enters the low temperature mode, so as to obtain the initial opening of the electronic expansion valve, and to make the electronic expansion valve enter the initial stage of a preset time length, and in the initial stage, when the system low pressure of the compressor is lower than a preset value, the opening of the electronic expansion valve is expanded on the basis of the initial opening;

[0100] The continuous adjustment module is used to adjust the opening of the electronic expansion valve in real time after the initial stage according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor.

[0101] Furthermore, the continuous adjustment module also determines whether the temperature at the outlet of the indoor unit coil is lower than a preset freezing point at a preset time interval, and if so, reduces the current opening of the electronic expansion valve.

[0102] The present invention also discloses another variable frequency air conditioning control system, which includes one or more processors, a memory and one or more programs, wherein the one or more programs are stored in the memory and are configured to be executed by the one or more processors, and the program includes instructions for executing the variable frequency air conditioning control method as described above. The processor can adopt a general central processing unit (CPU), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, which are used to execute relevant programs to realize the functions required to be executed by the modules in the variable frequency air conditioning control system of the embodiment of the present application, or to execute the variable frequency air conditioning control method of the method embodiment of the present application.

[0103] The present invention also discloses a computer-readable storage medium, which includes a computer program, and the computer program can be executed by a processor to complete the variable frequency air conditioner control method as described above. The computer-readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium can be a read-only memory (ROM), or a random access memory (RAM), or a magnetic medium, such as a floppy disk, a hard disk, a tape, a magnetic disk, or an optical medium, such as a digital versatile disc (DVD), or a semiconductor medium, such as a solid state disk (SSD), etc.

[0104] The embodiment of the present application also discloses a computer program product or a computer program, which includes a computer instruction stored in a computer-readable storage medium. A processor of an electronic device reads the computer instruction from the computer-readable storage medium, and the processor executes the computer instruction, so that the electronic device executes the above variable frequency air conditioner control method.

[0105] The above disclosure is only the preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the scope of the patent application of the present invention are still within the scope covered by the present invention.

Claims

1. A method for controlling a variable frequency air conditioner with a low temperature refrigeration function, characterized in that: include: Acquiring the ambient temperature of the environment where the compressor is located outdoors, and controlling the variable frequency air conditioner to switch between a normal temperature cooling mode and a low temperature cooling mode according to the ambient temperature; In the low-temperature refrigeration mode, the operating state of the compressor is regulated and controlled by a first regulating method, and the operating state of the fan in the outdoor unit is regulated and controlled by a second regulating method; The first adjustment method comprises: gradually lowering the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature; increasing the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature; The second adjustment method comprises: When the fan is in a loaded state or a deloaded state, obtaining a current system high pressure at the exhaust port of the compressor; When the system high pressure is lower than the currently allowed pressure operating range of the compressor, the target evaporation temperature is lowered based on the current target evaporation temperature, and at the same time, the current speed of the fan is maintained unchanged.

2. The variable frequency air conditioner control method with low temperature refrigeration function according to claim 1, characterized in that: The method of lowering the target evaporation temperature by the second adjustment method includes: When the system high pressure is lower than the pressure operation range, the target evaporation temperature is lowered at preset time intervals until the number of lowering times reaches a preset value or the target evaporation temperature reaches a minimum limit value; When the system high pressure is within the pressure operating range of the compressor, the target evaporating temperature is increased at preset time intervals until the target evaporating temperature is adjusted back to the initial value when the variable frequency air conditioner enters the low temperature cooling mode.

3. The variable frequency air conditioner control method with low temperature refrigeration function according to claim 1, characterized in that: In the low-temperature refrigeration mode, the working state of the electronic expansion valve in the indoor unit of the variable frequency air conditioner is also adjusted by a third adjustment method, and the third adjustment method includes: Controlling the opening of the electronic expansion valve to be halved to obtain the initial opening of the electronic expansion valve, and causing the electronic expansion valve to enter an initial stage of a preset time length; In the initial stage, when the system low pressure of the compressor is lower than a preset value, the opening of the electronic expansion valve is increased based on the initial opening; After the initial stage is over, the opening of the electronic expansion valve is adjusted in real time according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor.

4. The variable frequency air conditioner control method with low temperature refrigeration function according to claim 3, characterized in that: It is determined at a preset time interval whether the temperature at the outlet of the indoor unit coil is lower than a preset freezing point. If so, the current opening of the electronic expansion valve is reduced.

5. A variable frequency air conditioning control system with low temperature refrigeration function, characterized in that: include: A mode switching unit, which is used to control the variable frequency air conditioner to switch between a normal temperature cooling mode and a low temperature cooling mode according to the ambient temperature; A first regulating unit and a second regulating unit provided in the low temperature refrigeration mode; The first regulating unit is used to regulate and control the operating state of the compressor in the variable frequency air conditioner, and includes an evaporation temperature regulating module and a compressor regulating module; The evaporation temperature adjustment module is used to gradually lower the target evaporation temperature in a gradient manner according to the real-time value of the ambient temperature; The compressor adjustment module is used to increase the operating frequency of the compressor according to the difference between the current evaporation temperature and the target evaporation temperature; The second regulating unit is used to regulate and control the operating state of the fan located in the outdoor unit, and includes a high-voltage monitoring module and a fan regulating module; The high pressure monitoring module is used to obtain the current system high pressure at the exhaust port of the compressor when the fan is in a loaded state or a unloaded state; The fan adjustment module is used to lower the target evaporation temperature based on the current target evaporation temperature when the system high pressure is lower than the currently allowed pressure operating range of the compressor, while maintaining the current speed of the fan unchanged.

6. The variable frequency air conditioning control system with low temperature refrigeration function according to claim 5, characterized in that: The evaporation temperature adjustment module includes an upward adjustment module and a downward adjustment module; The downward adjustment module is used to adjust the target evaporation temperature downward at a preset time interval when the system high pressure is lower than the pressure operation range, until the number of downward adjustments reaches a preset value or the target evaporation temperature reaches a minimum limit value; The downward adjustment module is used to increase the target evaporating temperature at a preset time interval when the system high pressure is within the pressure operating range of the compressor, until the target evaporating temperature is adjusted back to the initial value when the variable frequency air conditioner enters the low-temperature cooling mode.

7. The variable frequency air conditioning control system with low temperature refrigeration function according to claim 5, characterized in that: In the low-temperature refrigeration mode, a third regulating unit is further provided for regulating the working state of the electronic expansion valve located in the indoor unit of the variable frequency air conditioner, and the third regulating unit includes an initial regulating module and a continuous regulating module; The initial adjustment module is used to control the opening of the electronic expansion valve to be halved when the variable frequency air conditioner initially enters the low temperature mode, so as to obtain the initial opening of the electronic expansion valve, and to make the electronic expansion valve enter the initial stage of a preset time length, and in the initial stage, when the system low pressure of the compressor is lower than a preset value, the opening of the electronic expansion valve is expanded on the basis of the initial opening; The continuous adjustment module is used to adjust the opening of the electronic expansion valve in real time according to the superheat at the inlet and outlet of the indoor unit coil and the return air superheat of the compressor after the initial stage ends.

8. The variable frequency air conditioning control system with low temperature refrigeration function according to claim 7, characterized in that: The continuous adjustment module also determines whether the temperature at the outlet of the indoor unit coil is lower than a preset freezing point at a preset time interval, and if so, reduces the current opening of the electronic expansion valve.

9. A variable frequency air conditioning control system, characterized in that: include: one or more processors; Memory; and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for executing the variable frequency air conditioning control method as described in any one of claims 1 to 4.

10. A computer-readable storage medium, characterized in that: It includes a computer program, which can be executed by a processor to complete the variable frequency air conditioner control method as described in any one of claims 1 to 4.

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