Control method and control device of multi-connected air conditioner and air conditioner

Abstract

The application provides a control method and device of a multi-connected air conditioner and the air conditioner. The control method of the multi-connected air conditioner according to the first aspect of the application comprises the following steps: determining that the multi-connected air conditioner operates in a refrigeration mode, and acquiring the operating state of the outdoor unit; determining that at least one of the outdoor units is in a shutdown state, and performing over-refrigerant detection; and determining that the over-refrigerant detection meets a set condition and lasts for at least a first set time length, and adjusting the opening degree of the electronic expansion valve of the outdoor unit in the shutdown state. The control method, device and air conditioner of the multi-connected air conditioner provided by the application can avoid the situation of excessive refrigerant, thereby ensuring the refrigeration effect and operation safety of the unit.

Description

Technical Field

[0001] This invention relates to the field of electrical technology, and in particular to a control method, control device, and air conditioner for multi-split air conditioners. Background Technology

[0002] In related technologies, in order to ensure that multiple outdoor units can still meet the user's cooling needs when running simultaneously, multi-split air conditioners are usually charged with a large amount of refrigerant to ensure the normal operation of multiple indoor units. However, when some indoor units of a multi-split air conditioning system are in standby mode, there may be an excess of refrigerant, which will lead to the following problems: (1) The pressure in the air conditioning pipeline increases, increasing the load on internal components, affecting the reliable operation of the system, and weakening the heat exchange effect. (2) The unit exhaust superheat is insufficient, which leads to protection shutdown. (3) The speed at which the refrigerant completes the phase change in the pipeline becomes slower, and it presents a gas-liquid mixture state, which will cause a sharp abnormal noise when passing through valves and compressors. Summary of the Invention

[0003] This invention provides a control method, control device, and air conditioner for multi-split air conditioners, which addresses the deficiencies in the prior art and achieves the following technical effects: avoiding refrigerant excess, thereby ensuring the cooling effect and operational safety of the unit.

[0004] A control method for a multi-split air conditioner according to a first aspect embodiment of the present invention includes:

[0005] Determine the operating cooling mode of the multi-split air conditioner and obtain the operating status of the outdoor unit;

[0006] Determine that at least one of the outdoor units is in a stopped state and perform a refrigerant test;

[0007] If the refrigerant detection meets the set conditions and continues for at least a first set time, adjust the opening of the electronic expansion valve of the outdoor unit that is in the off state.

[0008] According to an embodiment of the present invention, the step of determining that the refrigerant detection meets the set conditions and adjusting the opening of the electronic expansion valve of the outdoor unit in the shutdown state specifically includes:

[0009] Once the refrigerant detection meets the set conditions, the electronic expansion valve of the outdoor unit, which is in a shutdown state, is opened and remains open for at least the second set duration.

[0010] According to one embodiment of the present invention, the subcoolant detection includes:

[0011] The heat exchange superheat of the indoor unit and the exhaust superheat of the outdoor unit in operation are obtained.

[0012] The setting conditions include:

[0013] At least half of the indoor units have a heat exchange superheat difference from the target heat exchange superheat that is less than or equal to the set superheat difference, and at least one of the outdoor units in operation has an exhaust superheat that is less than or equal to the target exhaust superheat.

[0014] According to one embodiment of the present invention, the subcoolant detection includes:

[0015] Obtain the opening degree of the electronic expansion valve of the indoor unit;

[0016] The setting conditions include:

[0017] At least half of the indoor units have electronic expansion valves with an opening degree less than or equal to the set indoor opening degree.

[0018] According to one embodiment of the present invention, the subcoolant detection includes:

[0019] Obtain the outdoor ambient temperature and the high-pressure saturation temperature of the outdoor unit;

[0020] The setting conditions include:

[0021] The outdoor ambient temperature is greater than or equal to the set outdoor temperature, and the high-pressure saturation temperature of at least one of the outdoor units is greater than or equal to the set saturation temperature.

[0022] According to an embodiment of the present invention, the step of controlling the electronic expansion valve of the outdoor unit in the shutdown state to open and remain open for at least a first set time specifically includes:

[0023] The electronic expansion valve of the outdoor unit, which is in a stopped state, performs a valve cycle opening operation, that is, it opens to a set outdoor opening degree at set intervals and closes to zero within the second set time period.

[0024] According to one embodiment of the present invention, during the process of the electronic expansion valve of the outdoor unit in the shutdown state performing the valve cycle opening operation, the control method of the multi-split air conditioner further includes:

[0025] Obtain the outdoor ambient temperature and the valve outlet temperature of the electronic expansion valve of the outdoor unit when it is in shutdown state;

[0026] The execution logic is generated based on the outdoor ambient temperature and the valve outlet temperature, and the execution logic is used to control whether the valve cyclic opening operation is performed.

[0027] According to an embodiment of the present invention, the step of generating execution logic based on the outdoor ambient temperature and the valve outlet temperature, and controlling whether or not the valve cyclic opening operation is executed according to the execution logic, specifically includes:

[0028] If the difference between the outdoor ambient temperature and the valve outlet temperature is greater than or equal to a set temperature difference, the valve cyclic opening operation continues.

[0029] The valve cycle operation ends when the difference between the outdoor ambient temperature and the valve outlet temperature is less than the set temperature difference.

[0030] According to one embodiment of the present invention, the control method for a multi-split air conditioner further includes:

[0031] Once all outdoor units are confirmed to be operational, exit the refrigerant detection.

[0032] A control device for a multi-split air conditioner according to a second aspect of the present invention includes:

[0033] The acquisition module is used to determine the operating cooling mode of the multi-split air conditioner and acquire the operating status of the outdoor unit;

[0034] The first execution module is used to determine that at least one of the outdoor units is in a shutdown state and to perform a refrigerant detection.

[0035] The second execution module is used to determine that the refrigerant detection meets the set conditions and lasts for at least a first set time, and adjust the opening of the electronic expansion valve of the outdoor unit in the shutdown state.

[0036] An air conditioner according to a third aspect of the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the control method for a multi-split air conditioner as described in the first aspect of the present invention.

[0037] This invention proposes a control method for multi-split air conditioners. When a partial outdoor unit is detected to be shut down in cooling mode, the method executes a refrigerant overload detection program to determine if there is refrigerant excess in the multi-split air conditioner. If the refrigerant overload detection results meet the requirements, the opening of the electronic expansion valve of the shut-down outdoor unit is adjusted, thereby regulating the refrigerant flow in the operating indoor units of the multi-split air conditioner. This prevents refrigerant overload and ensures the unit's cooling effect and operational safety. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1This is a flowchart illustrating the control method for a multi-split air conditioner provided by the present invention;

[0040] Figure 2 This is a schematic diagram of the control device for a multi-split air conditioner provided by the present invention;

[0041] Figure 3 This is one of the structural schematic diagrams of the multi-split air conditioner provided by the present invention;

[0042] Figure 4 This is the second structural schematic diagram of the multi-split air conditioner provided by the present invention;

[0043] Figure 5 This is a schematic diagram of the structure of the electronic device provided by the present invention.

[0044] Figure label:

[0045] 1. Compressor; 2. Gas-liquid separator; 3. Four-way reversing valve; 4. Outdoor fan; 5. Outdoor heat exchanger; 6. Outdoor unit electronic expansion valve; 7. Third temperature sensor; 8. Economizer; 9. Economizer electronic expansion valve; 10. Liquid pipe shut-off valve; 11. Gas pipe shut-off valve; 12. Refrigerant cooling valve; 13. Enthalpy-increasing valve; 14. Indoor unit electronic expansion valve; 15. First temperature sensor; 16. Indoor heat exchanger; 17. Second temperature sensor. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] The control method, control device, and air conditioner for multi-split air conditioners proposed in this invention are described below with reference to the accompanying drawings. Before providing a detailed description of the embodiments of this invention, the overall application scenario is first described. The control method, control device, electronic device, and computer-readable storage medium for multi-split air conditioners of this invention can be applied locally to the air conditioner, to cloud platforms in the Internet field, or to other types of cloud platforms in the Internet field, or to third-party devices. These third-party devices may include various types such as mobile phones, tablets, laptops, in-vehicle computers, and other smart terminals.

[0048] The following description uses a control method applicable to multi-split air conditioners as an example. It should be understood that the control method of this invention can also be applied to cloud platforms and third-party devices. It should also be noted that the control method for multi-split air conditioners proposed in this invention is targeted, meaning that this method is generally applicable to air conditioners performing cooling in low-temperature or high-temperature environments.

[0049] In the control method of the multi-split air conditioner of the present invention, the multi-split air conditioner includes at least two outdoor units and at least two indoor units. The outdoor units and indoor units are interconnected by piping. For the multi-split air conditioner, the outdoor side adopts air-cooled heat exchange and the indoor side adopts direct evaporation heat exchange.

[0050] like Figure 1 As shown, a control method for a multi-split air conditioner according to a first aspect embodiment of the present invention includes:

[0051] Step S1: Determine the operating cooling mode of the multi-split air conditioner and obtain the operating status of the outdoor unit;

[0052] Step S2: Determine that at least one of the outdoor units is in a shutdown state and perform a refrigerant detection.

[0053] Step S3: Determine that the refrigerant detection meets the set conditions and lasts for at least a first set time, and adjust the opening of the electronic expansion valve 6 of the outdoor unit that is in the shutdown state.

[0054] According to the control method of a multi-split air conditioner according to an embodiment of the present invention, wherein the multi-split air conditioner includes at least two indoor units and at least two outdoor units, the specific working process of the control method given by the present invention is as follows: First, after determining that the multi-split air conditioner is turned on and in operation, the current operating mode of the multi-split air conditioner is obtained. When it is determined that the multi-split air conditioner is currently in cooling mode, the controller then sequentially obtains the current operating status of each outdoor unit and determines whether each outdoor unit is in the on state or the off state.

[0055] When the controller determines that at least one outdoor unit is in a stopped state, the controller controls the multi-split air conditioner to perform a refrigerant detection program, that is, to detect whether there is excess refrigerant in the multi-split air conditioner. If the result of the refrigerant detection meets the preset conditions and continues for at least the first preset time, it proves that there is excess refrigerant in the multi-split air conditioner due to the shutdown of some outdoor units. At this time, the controller will adjust the opening of the electronic expansion valve 6 of the outdoor unit in the stopped state, thereby adjusting the refrigerant flow in the indoor unit that is running in the multi-split air conditioner, avoiding excess refrigerant, and thus ensuring the cooling effect and operational safety of the unit.

[0056] In related technologies, in order to ensure that multiple outdoor units can still meet the user's cooling needs when running simultaneously, multi-split air conditioners are usually charged with a large amount of refrigerant to ensure the normal operation of multiple indoor units. However, when some indoor units of a multi-split air conditioning system are in standby mode, there may be an excess of refrigerant, which will lead to the following problems: (1) The pressure in the air conditioning pipeline increases, increasing the load on internal components, affecting the reliable operation of the system, and weakening the heat exchange effect. (2) The unit exhaust superheat is insufficient, which leads to protection shutdown. (3) The speed at which the refrigerant completes the phase change in the pipeline becomes slower, and it presents a gas-liquid mixture state, which will cause a sharp abnormal noise when passing through valves and compressors.

[0057] To address the technical deficiencies in the aforementioned related technologies, this invention proposes a control method for multi-split air conditioners. This method, upon detecting that some outdoor units are in a stopped state during cooling mode, executes an over-refrigerant detection program to determine if there is an excess of refrigerant within the multi-split air conditioner. If the over-refrigerant detection result meets the conditions, the opening of the electronic expansion valve 6 of the stopped outdoor unit is adjusted, thereby regulating the refrigerant flow in the operating indoor units of the multi-split air conditioner, preventing refrigerant over-refrigerant, and thus ensuring the unit's cooling effect and operational safety.

[0058] In summary, by utilizing the control method of the multi-split air conditioner of the present invention, when some indoor units of a multi-split air conditioner system are in standby mode, the amount of refrigerant in the system can be monitored and adjusted in a timely manner. That is, by adjusting the amount of refrigerant in the system in real time, the efficiency and rationality of the multi-split system in operation can be achieved, and the cooling effect and operational safety of the unit can be guaranteed.

[0059] Furthermore, the control method of the present invention can overcome the technical problems existing in related technologies. That is, the control method of the present invention can avoid the pressure rise in the air conditioning pipeline, keep the load of the internal components stable, ensure the reliable operation of the system, and ensure the heat exchange effect; it can also ensure the exhaust superheat of the unit and avoid the state of protection shutdown; in addition, it can also avoid the noise problem caused by excessive refrigerant and reduce the operating load.

[0060] According to some embodiments of the present invention, the step of determining that the subcoolant detection meets the set conditions and continues for at least a first set time, and adjusting the opening of the electronic expansion valve 6 of the outdoor unit in the off state, specifically includes:

[0061] If the refrigerant detection meets the set conditions and continues for at least a first set time, the electronic expansion valve 6 of the outdoor unit in the shutdown state is controlled to open and continue for at least a second set time.

[0062] In this embodiment, when the controller determines that the result of the refrigerant detection program meets the set conditions and lasts for at least the first set duration, it proves that there is an excess of refrigerant in the current multi-split air conditioning system. Therefore, the controller will control the electronic expansion valve 6 of the outdoor unit in the shutdown state to open and last for at least the second set duration, so that the excess refrigerant in the system is diverted to the outdoor unit in the shutdown state, that is, the excess refrigerant in the system is removed from the refrigerant circulation, thereby ensuring the rationality of the refrigerant flow in the indoor unit in the running state.

[0063] According to some embodiments of the present invention, refrigerant overload detection may include detecting various operating parameters of the indoor unit and / or the outdoor unit, and determining whether the conditions for refrigerant overload are met by judging the detection results, thereby determining whether there is refrigerant overload in the system. Several specific embodiments of refrigerant overload detection given in this method will be described in detail below.

[0064] According to one embodiment of the present invention, the supercoolant detection includes: acquiring the heat exchange superheat of the indoor unit and the exhaust superheat of the outdoor unit in operation.

[0065] The set conditions include: the difference between the heat exchange superheat of at least half of the indoor units and the target heat exchange superheat is less than or equal to the set superheat difference, and the exhaust superheat of at least one of the outdoor units in operation is less than or equal to the target exhaust superheat.

[0066] Specifically, the controller obtains the heat exchange superheat of the indoor unit by acquiring the difference between the refrigerant inlet temperature and the refrigerant outlet temperature of the indoor heat exchanger. After obtaining the heat exchange superheat of the indoor unit and the exhaust superheat of the outdoor unit, the controller judges the above two parameters. When it is determined that the following conditions are met: the difference between the heat exchange superheat of at least half of the indoor units and the target heat exchange superheat is less than or equal to the set superheat difference, and the exhaust superheat of at least one of the outdoor units in operation is less than or equal to the target exhaust superheat, and the above conditions are determined to last for at least a second set time, it is proven that there is excess refrigerant in the multi-split air conditioning system. At this time, the controller will control the electronic expansion valve 6 of the outdoor unit in the shutdown state to open, so that the excess refrigerant in the system is diverted to the outdoor unit in the shutdown state, that is, the excess refrigerant in the system is removed from the refrigerant circulation, thereby ensuring the rationality of the refrigerant flow in the indoor unit in the operation state.

[0067] According to another embodiment of the present invention, the refrigerant detection includes: acquiring the opening degree of the electronic expansion valve 14 of the indoor unit. The setting condition includes: the opening degree of the electronic expansion valve 14 of at least half of the indoor units is less than or equal to a set indoor opening degree.

[0068] Specifically, after the controller obtains the opening degree of the electronic expansion valve 14 of the indoor unit, it judges the above parameters. When it is determined that the following conditions are met: the opening degree of the electronic expansion valve 14 of at least half of the indoor units is less than or equal to the set indoor opening degree, and the above conditions are determined to last for at least the second set time, it is proven that there is excess refrigerant in the multi-split air conditioning system. At this time, the controller will control the electronic expansion valve 6 of the outdoor unit that is in the shutdown state to open, so that the excess refrigerant in the system is diverted to the outdoor unit in the shutdown state, that is, the excess refrigerant in the system is removed from the refrigerant circulation, thereby ensuring the rationality of the refrigerant flow in the indoor unit that is in the running state.

[0069] According to another embodiment of the present invention, the refrigerant detection includes: acquiring the outdoor ambient temperature and the high-pressure saturation temperature of the outdoor unit. The setting conditions include: the outdoor ambient temperature is greater than or equal to a set outdoor temperature, and at least one of the high-pressure saturation temperatures of the outdoor unit is greater than or equal to a set saturation temperature.

[0070] Specifically, after the controller obtains the outdoor ambient temperature and the high-pressure saturation temperature of the outdoor unit, it judges the above parameters. When it is determined that the following conditions are met: the outdoor ambient temperature is greater than or equal to the set outdoor temperature, and the high-pressure saturation temperature of at least one of the outdoor units is greater than or equal to the set saturation temperature, and the above conditions are determined to last for at least a second set time, it is proven that there is excess refrigerant in the multi-split air conditioning system. At this time, the controller will control the electronic expansion valve 6 of the outdoor unit that is in the shutdown state to open, so that the excess refrigerant in the system is diverted to the outdoor unit in the shutdown state, that is, the excess refrigerant in the system is removed from the refrigerant circulation, thereby ensuring the rationality of the refrigerant flow in the indoor unit that is in the running state.

[0071] It should be explained that the "at least half of the indoor units" mentioned in the above embodiments refers to half or more of all indoor units. For example, if a multi-split air conditioner has four outdoor units, then two outdoor units, three outdoor units, and four outdoor units would satisfy the requirement of "at least half of the outdoor units".

[0072] According to some embodiments of the present invention, the step of controlling the electronic expansion valve 6 of the outdoor unit in the shutdown state to open and remain open for at least a first set time specifically includes:

[0073] The electronic expansion valve 6 of the outdoor unit, which is in a stopped state, performs a valve cycle opening operation. The valve cycle opening operation refers to opening the electronic expansion valve 6 to a set outdoor opening degree at set intervals and closing it to zero within the second set time period.

[0074] According to some embodiments of the present invention, during the process of the electronic expansion valve 6 of the outdoor unit in the shutdown state performing the valve cycle opening operation, the control method of the multi-split air conditioner further includes:

[0075] The outdoor ambient temperature and the valve outlet temperature of the electronic expansion valve 6 of the outdoor unit, which is in a shutdown state, are obtained.

[0076] The execution logic is generated based on the outdoor ambient temperature and the valve outlet temperature, and the execution logic is used to control whether the valve cyclic opening operation is performed.

[0077] Furthermore, the step of generating execution logic based on the valve outlet temperature and the outdoor ambient temperature, and controlling whether or not the valve cyclic opening operation is executed according to the execution logic, specifically includes:

[0078] If the difference between the valve outlet temperature and the outdoor ambient temperature is greater than or equal to a set temperature difference, the valve cyclic opening operation continues.

[0079] The valve cycle operation ends when the difference between the valve outlet temperature and the outdoor ambient temperature is less than the set temperature difference.

[0080] In this embodiment, if the difference between the valve outlet temperature and the outdoor ambient temperature is greater than or equal to the set temperature difference, it proves that the valve outlet temperature is higher than the outdoor ambient temperature. Therefore, the refrigerant in the refrigerant pipe of the outdoor unit in the shutdown state can dissipate heat by utilizing the temperature difference between it and the outdoor environment, so that when this part of the refrigerant re-enters the refrigerant circulation, it meets the temperature requirements. Therefore, the controller can control the valve circulation opening operation to continue to be executed, thereby diverting excess refrigerant without affecting the cooling effect.

[0081] If the difference between the valve outlet temperature and the outdoor ambient temperature is less than the set temperature difference, it proves that the difference between the valve outlet temperature and the outdoor ambient temperature is small. At this time, the refrigerant in the refrigerant pipe of the outdoor unit in the shutdown state cannot dissipate heat by utilizing the temperature difference between it and the outdoor environment, or its heat dissipation effect is poor. As a result, when this part of the refrigerant re-enters the refrigerant circulation, it cannot meet the temperature requirements. Therefore, the controller will immediately interrupt the valve circulation opening operation and continue to execute the cooling mode to avoid affecting the cooling effect of the air conditioner.

[0082] According to some embodiments of the present invention, the control method for multi-split air conditioners further includes:

[0083] Once all outdoor units are confirmed to be operational, exit the refrigerant detection.

[0084] It is understandable that if all outdoor units are in operation, there will no longer be a problem of excess refrigerant in the multi-split air conditioning system. Therefore, the controller will control the air conditioner to directly exit the refrigerant detection program.

[0085] The following describes a specific embodiment of the control method for a multi-split air conditioner according to the present invention.

[0086] In the cooling mode of a multi-split air conditioner, the refrigerant overload detection is ineffective when all outdoor units of the multi-split air conditioner are turned on and running; the refrigerant overload detection is effective when some outdoor units of the multi-split air conditioner are in a stopped state.

[0087] Under refrigerant detection, the controller will acquire the following parameters: the heat exchange superheat of the indoor unit, the exhaust superheat of the outdoor unit in operation, the opening degree of the electronic expansion valve 6 of the indoor unit, the outdoor ambient temperature, and the high-pressure saturation temperature of the outdoor unit.

[0088] After obtaining the above parameters, if the detection result meets at least one of the following three conditions, the refrigerant control degree will continue to be implemented. The three conditions are: (1) the difference between the heat exchange superheat of at least half of the indoor units and the target heat exchange superheat is less than or equal to -1°C, and the exhaust superheat of at least one of the outdoor units in operation is less than or equal to 10°C, and the above conditions last for at least 1 minute; (2) the opening degree of the electronic expansion valve 14 of at least half of the indoor units is less than or equal to 90 steps, and the above conditions last for at least 1 minute; (3) the outdoor ambient temperature is greater than or equal to 40°C, and the high pressure saturation temperature of at least one of the outdoor units is greater than or equal to 58°C, and the above conditions last for at least 1 minute.

[0089] When the test result meets at least one of the above three conditions, the electronic expansion valve 6 of the outdoor unit in the shutdown state opens to 100pls every fifteen minutes. During this period, the relationship between the temperature Te (i.e., the valve outlet temperature) of the outdoor electronic expansion valve 6 and the outdoor ambient temperature Tao is detected. After ten seconds, it closes to 0pls.

[0090] When Te-Tao ≥ 3℃, check if the unit meets any of the above-mentioned subcooling refrigerant detection conditions. If it does, reopen the outdoor electronic expansion valve for 6 to 100 pls and repeat the above cycle until the unit no longer meets any of the subcooling refrigerant detection conditions. If the unit does not meet any of the above-mentioned subcooling refrigerant detection conditions, maintain the current state and continue cooling. When Te-Tao < 3℃, the unit maintains the current state and continues cooling.

[0091] The control device for a multi-split air conditioner provided by the present invention is described below. The control device for a multi-split air conditioner described below can be referred to in correspondence with the control method for a multi-split air conditioner described above.

[0092] like Figure 2 As shown, the control device for a multi-split air conditioner according to a second aspect embodiment of the present invention includes:

[0093] The acquisition module 110 is used to determine the operating cooling mode of the multi-split air conditioner and acquire the operating status of the outdoor unit;

[0094] The first execution module 120 is used to determine that at least one of the outdoor units is in a shutdown state and to perform a refrigerant detection.

[0095] The second execution module 130 is used to determine that the refrigerant detection meets the set conditions and lasts for at least a first set time, and adjust the opening of the electronic expansion valve of the outdoor unit in the shutdown state.

[0096] like Figure 3 and Figure 4 As shown, a multi-split air conditioner according to a third aspect embodiment of the present invention includes at least two outdoor units, at least two indoor units, and a control device for the multi-split air conditioner described above.

[0097] like Figure 3 and Figure 4 As shown, according to some embodiments of the present invention, each indoor unit includes an indoor heat exchanger 16, an indoor unit electronic expansion valve 14, a first temperature sensor 15, and a second temperature sensor 17, wherein the indoor unit electronic expansion valve 14 and the first temperature sensor 15 are located at the refrigerant inlet of the indoor heat exchanger 16, and the second temperature sensor 17 is located at the refrigerant outlet of the indoor heat exchanger 16.

[0098] Each outdoor unit includes a compressor 1, a gas-liquid separator 2, a four-way reversing valve 3, an outdoor heat exchanger 5, an outdoor unit electronic expansion valve 6, a third temperature sensor 7, an economizer 8, an economizer electronic expansion valve 9, a liquid line shut-off valve 10, a refrigerant cooling valve 12, and an enthalpy-increasing valve 13, all connected via refrigerant piping. An outdoor fan 4 is also installed at the outdoor heat exchanger 5.

[0099] Figure 5 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 5As shown, the electronic device may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logical instructions in the memory 830 to execute a control method for a multi-split air conditioner. The method includes: determining the operating cooling mode of the multi-split air conditioner and obtaining the operating status of the outdoor unit; determining that at least one of the outdoor units is in a stopped state and performing refrigerant overload detection; determining that the refrigerant overload detection meets set conditions and lasts for at least a first set duration, and adjusting the opening degree of the electronic expansion valve 6 of the outdoor unit in the stopped state.

[0100] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0101] On the other hand, the present invention also provides a computer program product, the computer program product including a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a control method for a multi-split air conditioner. The method includes: determining the operating cooling mode of the multi-split air conditioner and obtaining the operating status of the outdoor unit; determining that at least one of the outdoor units is in a shutdown state and performing refrigerant detection; determining that the refrigerant detection meets set conditions and lasts for at least a first set duration, and adjusting the opening of the electronic expansion valve 6 of the outdoor unit in the shutdown state.

[0102] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements a control method for a multi-split air conditioner, the method comprising: determining the operating cooling mode of the multi-split air conditioner and obtaining the operating status of the outdoor unit; determining that at least one of the outdoor units is in a stopped state and performing refrigerant overload detection; determining that the refrigerant overload detection meets set conditions and lasts for at least a first set duration, and adjusting the opening degree of the electronic expansion valve 6 of the outdoor unit in the stopped state.

[0103] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0104] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method of a multi VRF air conditioner, characterized by, The method comprises the steps of: determining that the multi-split air conditioner is in a cooling mode, and obtaining the running state of an outdoor unit; determining that at least one of the outdoor units is in a shutdown state, and performing overcooling detection; determining that the overcooling detection meets a set condition and lasts for at least a first set time length, and adjusting the opening degree of an electronic expansion valve of the outdoor unit in the shutdown state; the overcooling detection comprises the steps of: obtaining the heat exchange superheat of an indoor unit and the exhaust gas superheat of the outdoor unit in the running state; the set condition comprises the steps of: the difference between the heat exchange superheat of at least half of the indoor units and a target heat exchange superheat is less than or equal to a set superheat difference, and the exhaust gas superheat of at least one of the outdoor units in the running state is less than or equal to a target exhaust gas superheat; or, the overcooling detection comprises the steps of: obtaining the opening degree of the electronic expansion valve of the indoor unit; the set condition comprises the steps of: the opening degree of the electronic expansion valve of at least half of the indoor units is less than or equal to a set indoor opening degree; or, the overcooling detection comprises the steps of: obtaining the outdoor environment temperature and the high-pressure pressure saturation temperature of the outdoor unit; the set condition comprises the steps of: the outdoor environment temperature is greater than or equal to a set outdoor temperature, and the high-pressure pressure saturation temperature of at least one of the outdoor units is greater than or equal to a set saturation temperature.

2. The control method of a multi VRF air conditioning according to claim 1, characterized in that, The step of determining that the overcooling detection meets a set condition and lasts for at least a first set time length, and adjusting the opening degree of the electronic expansion valve of the outdoor unit in the shutdown state, specifically comprises the steps of: determining that the overcooling detection meets a set condition and lasts for at least a first set time length, and controlling the electronic expansion valve of the outdoor unit in the shutdown state to be opened and last for at least a second set time length.

3. The control method of a multi VRF air conditioning according to claim 2, characterized in that, The step of controlling the electronic expansion valve of the outdoor unit in the shutdown state to be opened and last for at least a second set time length, specifically comprises the steps of: controlling the electronic expansion valve of the outdoor unit in the shutdown state to perform a valve cycle opening operation, that is, to be opened to a set outdoor opening degree every set interval time length and to be closed to zero within the second set time length.

4. The control method of a multi VRF air conditioning according to claim 3, characterized in that, In the process that the electronic expansion valve of the outdoor unit in the shutdown state performs the valve cycle opening operation, further comprising the steps of: obtaining the outdoor environment temperature and the valve outlet temperature of the electronic expansion valve of the outdoor unit in the shutdown state; generating an execution logic according to the outdoor environment temperature and the valve outlet temperature, and controlling whether to perform the valve cycle opening operation according to the execution logic.

5. The control method of a multi VRF air conditioning according to claim 4, characterized in that, The step of generating an execution logic according to the outdoor environment temperature and the valve outlet temperature, and controlling whether to perform the valve cycle opening operation according to the execution logic, specifically comprises the steps of: continuing to perform the valve cycle opening operation according to the difference between the outdoor environment temperature and the valve outlet temperature being greater than or equal to a set temperature difference value; ending the valve cycle opening operation according to the difference between the outdoor environment temperature and the valve outlet temperature being less than the set temperature difference value.

6. The control method of a multi VRF air conditioning according to claim 1 or 2, characterized in that, Further comprising the steps of: determining that all of the outdoor units are in the running state, and exiting the overcooling detection.

7. A control device of a multi VRF air conditioner, characterized by comprising: The control method applied to the multi-split air conditioner of any one of claims 1 to 6, comprising: an obtaining module configured to determine that the multi-split air conditioner is in a cooling mode, and obtain the running state of an outdoor unit; The first execution module is configured to determine that at least one of the outdoor units is in a shutdown state, and perform a supercooling medium detection. The second execution module is configured to determine that the supercooling medium detection meets a set condition and lasts for at least a first set time length, and adjust an opening degree of an electronic expansion valve of the outdoor unit in the shutdown state.

8. An air conditioner comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor implements the program to implement the control method of the multi-split air conditioner according to any one of claims 1 to 6.

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