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

Abstract

The application relates to the technical field of air conditioners, and provides a control method and a control device of a multi-connected air conditioner and the multi-connected air conditioner. The control method of the multi-connected air conditioner comprises the following steps: obtaining the working state and the operation mode of multiple indoor units; determining whether at least one of the multiple indoor units is in a shutdown state, and if so, performing over-coolant detection; determining whether the over-coolant detection meets a set condition and lasts for at least a first set time length, and if so, running a corresponding over-coolant control program according to the operation mode of the multiple indoor units. When over-coolant exists in the system, the operation mode of the multiple indoor units is used to determine the corresponding over-coolant control program, the coolant amount in the system is adjusted in time, the operation efficiency of the air conditioner is improved, the load of internal elements such as a compressor is reduced, and the noise of the system is reduced. When the operation modes of the indoor units are different, the control of the coolant amount is more complex, corresponding over-coolant control programs are adopted according to different operation modes of the multiple indoor units, and the programs are more targeted.

Description

Technical Field

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

[0002] Multi-split air conditioning refers to an air conditioning system in which one or more outdoor units are connected to two or more indoor units via piping. Multi-split air conditioning systems use a three-pipe refrigerant circulation system, where the refrigerant common pipe consists of a high-pressure pipe, a low-pressure pipe, and a liquid refrigerant pipe. This allows the indoor units to adjust their cooling or heating requirements in real time, resulting in high comfort and energy efficiency. In related technologies, to ensure that user needs are met even when multiple outdoor units are operating simultaneously, multi-split air conditioning systems are typically charged with a larger amount of refrigerant. However, when some indoor units are off or in standby mode, refrigerant excess may occur, leading to reduced air conditioning efficiency, increased load on internal components, and sharp abnormal noises. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes a control method for multi-split air conditioners. When some indoor units are shut down, a refrigerant overload detection and control program can be executed to adjust the refrigerant quantity in the system, maintain the stability of the refrigerant quantity in the system, thereby improving the operating efficiency of the air conditioner, reducing the load on internal components such as the compressor, and reducing system noise.

[0004] The present invention also provides a control device for a multi-split air conditioner.

[0005] The present invention also provides a multi-split air conditioner.

[0006] According to a first aspect embodiment of the present invention, a control method for a multi-split air conditioner is provided, wherein the multi-split air conditioner includes multiple indoor units, and the control method for the multi-split air conditioner includes:

[0007] Obtain the working status and operating mode of multiple indoor units;

[0008] If at least one of the indoor units is determined to be in a stopped state, a refrigerant detection is performed.

[0009] If the refrigerant detection meets the set conditions and continues for at least a first set duration, then the corresponding refrigerant control program is run according to the operating modes of the multiple indoor units.

[0010] According to an embodiment of the present invention, the step of running the corresponding refrigerant control program according to the operating modes of the plurality of indoor units specifically includes:

[0011] If it is determined that all the indoor units are running in cooling mode, then the multi-split air conditioner is controlled to run the first refrigerant control program to adjust the amount of refrigerant in the system through the electronic expansion valve of the indoor unit in the off state;

[0012] If it is determined that some of the multiple indoor units operate in cooling mode and others in heating mode, then the multi-split air conditioner is controlled to run a second refrigerant control program to adjust the amount of refrigerant in the system through the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the off state.

[0013] According to an embodiment of the present invention, the step of controlling the multi-split air conditioner to operate the first refrigerant control program specifically includes:

[0014] The high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state are both closed. The electronic expansion valve of the indoor unit in the shutdown state is controlled to open to a set opening degree at a second set time interval, and then completely close after a third set time interval.

[0015] According to one embodiment of the present invention, the step of controlling the multi-split air conditioner to operate the first refrigerant control program further includes:

[0016] During the period when the electronic expansion valve of the indoor unit is in the shutdown state is opened to a set opening degree, the first temperature at the inlet of the evaporator of the current indoor unit and the indoor unit ambient temperature are obtained.

[0017] If the difference between the first temperature and the indoor unit ambient temperature is greater than or equal to the first set temperature, then the multi-split air conditioner is controlled to perform refrigerant detection and subsequent steps.

[0018] If the difference between the first temperature and the indoor unit ambient temperature is less than the first set temperature, then the multi-split air conditioner is controlled to maintain its current operating state.

[0019] According to an embodiment of the present invention, the step of controlling the operation of the second refrigerant control program in the multi-split air conditioner specifically includes:

[0020] The electronic expansion valve of the indoor unit in the shutdown state, as well as the high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state, are all kept closed. The high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state is opened for a fifth set time interval every fourth set time interval.

[0021] According to one embodiment of the present invention, the step of controlling the multi-split air conditioner to operate the second refrigerant control program further includes:

[0022] During the period when the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit is open while the indoor unit is in a shutdown state, the second temperature at the outlet of the evaporator of the current indoor unit and the indoor unit ambient temperature are obtained.

[0023] If the difference between the second temperature and the indoor unit ambient temperature is greater than or equal to the second set temperature, then the multi-split air conditioner is controlled to perform refrigerant detection and subsequent steps.

[0024] If the difference between the second temperature and the indoor unit ambient temperature is less than the second set temperature, the multi-split air conditioner is controlled to maintain its current operating state.

[0025] According to one embodiment of the present invention, the subcoolant detection includes:

[0026] The heat exchange temperature difference of each of the indoor units in operation, and the exhaust superheat of the outdoor unit are obtained.

[0027] The setting conditions include:

[0028] At least half of the indoor units in operation have a heat exchange temperature difference less than or equal to the target superheat temperature, and the exhaust superheat of the outdoor unit is less than or equal to the target exhaust superheat.

[0029] According to one embodiment of the present invention, the subcoolant detection includes:

[0030] Obtain the opening degree of the electronic expansion valve of each of the indoor units in operation;

[0031] The setting conditions include:

[0032] At least half of the indoor units in operation have electronic expansion valves with an opening degree less than or equal to the set subcooling opening degree.

[0033] According to one embodiment of the present invention, the subcoolant detection includes:

[0034] Obtain the outdoor ambient temperature and the high-pressure saturation temperature of the outdoor unit;

[0035] The setting conditions include:

[0036] The outdoor ambient temperature is greater than or equal to the set outdoor temperature, and the high-pressure saturation temperature of the outdoor unit is greater than or equal to the set saturation temperature.

[0037] A control device for a multi-split air conditioner according to a second aspect embodiment of the present invention includes:

[0038] The acquisition module is used to acquire the working status and operating mode of multiple indoor units;

[0039] The first execution module is used to determine if at least one of the multiple indoor units is in a shutdown state, and then perform a refrigerant detection.

[0040] 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 then runs the corresponding refrigerant control program according to the operating modes of the multiple indoor units.

[0041] A multi-split 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, characterized in that the processor executes the program to implement a control method for the multi-split air conditioner according to a first aspect of the present invention.

[0042] The above-described one or more technical solutions of this invention have at least one of the following technical effects:

[0043] According to a first aspect embodiment of the present invention, a control method for a multi-split air conditioner includes multiple indoor units. The control method includes: acquiring the operating status and operating mode of the multiple indoor units; determining that at least one of the multiple indoor units is in a shutdown state, then performing refrigerant overload detection; determining that the refrigerant overload detection meets set conditions and lasts for at least a first set duration, then running a corresponding refrigerant overload control program according to the operating mode of the multiple indoor units. When some indoor units of the multi-split air conditioner are in a shutdown state, there may be an excess of refrigerant in the refrigerant circulation system. Timely refrigerant overload detection is performed. If the refrigerant overload detection meets set conditions and lasts for at least a first set duration, it indicates that there is excess refrigerant in the system. The corresponding refrigerant overload control program is determined through the operating modes of the multiple indoor units, and the refrigerant quantity in the system is adjusted in a timely manner to maintain the stability of the refrigerant quantity in the system, thereby improving the operating efficiency of the air conditioner, reducing the load on internal components such as the compressor, and reducing system noise. It should be noted that multiple indoor units of a multi-split air conditioner may have different operating modes. When the indoor units operate in different modes, the control of refrigerant quantity in the system becomes more complex. Therefore, when multiple indoor units operate in different modes, it is more targeted to adopt corresponding refrigerant control programs, which results in a more stable refrigerant quantity in the system. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1This is one of the flowcharts for the control method of a multi-split air conditioner provided in an embodiment of the present invention;

[0046] Figure 2 This is the second flowchart of the control method for a multi-split air conditioner provided in an embodiment of the present invention;

[0047] Figure 3 This is a schematic diagram of the structure of a multi-split air conditioner provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the reversing valve box of a multi-split air conditioner provided in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the control device for a multi-split air conditioner provided in an embodiment of the present invention.

[0050] Figure label:

[0051] 1. Compressor; 2. Oil separator; 3. High-pressure sensor; 4. Four-way valve; 5. Condenser; 6. Electronic expansion valve of the first outdoor unit; 7. Electronic expansion valve of the second outdoor unit; 8. Subcooling electronic expansion valve; 9. Subcooler; 10. Liquid line shut-off valve; 11. High-pressure gas line shut-off valve; 12. Low-pressure gas line shut-off valve; 13. Low-pressure sensor; 14. Injection solenoid valve; 15. Gas-liquid separator; 16. Enthalpy-increasing solenoid valve; 17. Reversing valve box; 18. Indoor unit electronic expansion valve; 19. TC1 temperature sensor; 20. Evaporator; 21. TC2 temperature sensor; 22. High-pressure gas line shut-off valve; 23. Low-pressure gas line shut-off valve;

[0052] 200. Acquisition module; 210. First execution module; 220. Second execution module. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of the invention clearer, the technical solutions of the invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0054] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0055] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0056] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0057] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0058] In related technologies, in order to ensure that the user's needs can still be met when multiple outdoor units are running at the same time, multi-split air conditioning systems are usually charged with a large amount of refrigerant. However, when some indoor units are in a shutdown or standby state, there may be an excess of refrigerant, which can lead to problems such as reduced air conditioning operating efficiency, high load on internal components, and sharp abnormal noises.

[0059] This invention provides a multi-split air conditioner; please refer to [link / reference]. Figures 3 to 4 A multi-split air conditioner includes an outdoor unit and multiple indoor units. The outdoor unit has liquid pipes, high-pressure gas pipes and low-pressure gas pipes. Multiple indoor units are connected in parallel. Each indoor unit is connected to the liquid pipe, high-pressure gas pipe and low-pressure gas pipe through a reversing valve box 17.

[0060] Each indoor unit includes an indoor unit electronic expansion valve 18 and an evaporator 20 connected via refrigerant piping. A TC1 temperature sensor is installed at the inlet of the evaporator 20 to detect the first temperature, and a TC2 temperature sensor is installed at the outlet of the evaporator 20 to detect the second temperature. The heat exchange temperature difference can be calculated based on the first and second temperatures.

[0061] The reversing valve box 17 includes a box body, a low-pressure gas pipe connection pipe and a high-pressure gas pipe connection pipe. A low-pressure gas pipe shut-off valve 12 is installed on the low-pressure gas pipe connection pipe, and a high-pressure gas pipe shut-off valve 11 is installed on the high-pressure gas pipe connection pipe. The low-pressure gas pipe connection pipe and the high-pressure gas pipe connection pipe are connected to the outlet of the evaporator 20.

[0062] Please see Figure 3 The outdoor unit includes a compressor 1, an oil separator 2, a high-pressure sensor 3, a four-way valve 4, a condenser 5, a first outdoor unit electronic expansion valve 6, a second outdoor unit electronic expansion valve 7, a subcooling electronic expansion valve 8, a subcooler 9, a liquid pipe shut-off valve 10, and a gas-liquid separator 15, all connected via refrigerant piping. Additionally, a liquid pipe shut-off valve 10 is installed on the liquid pipe, a high-pressure gas pipe shut-off valve 11 is installed on the high-pressure gas pipe, and a low-pressure gas pipe shut-off valve 12 is installed on the low-pressure gas pipe. A low-pressure sensor 13 and an injection solenoid valve 14 are installed on the piping between the four-way valve 4 and the gas-liquid separator 15. An enthalpy-increasing solenoid valve 16 is installed on the piping between the subcooler 9 and the compressor 1, and the injection solenoid valve 14 is connected to the piping between the subcooler 9 and the compressor 1.

[0063] It should be noted that the number of outdoor units is not limited to one, and the electronic components of the outdoor units can be increased or decreased according to actual needs. The multi-split air conditioner provided in this embodiment of the invention can run corresponding refrigerant control programs when multiple indoor units are operating in the same or different modes, resulting in better targeted control of the refrigerant quantity within the system and a more stable refrigerant quantity within the system.

[0064] The control method for a multi-split air conditioner according to the first aspect embodiment of the present invention is described in the following text. Figures 1 to 5 ,include:

[0065] S100: Obtain the working status and operating mode of multiple indoor units.

[0066] S200: If at least one of the multiple indoor units is found to be in a stopped state, then a refrigerant detection is performed.

[0067] S300: If the refrigerant detection meets the set conditions and continues for at least the first set duration, then the corresponding refrigerant control program will be run according to the operating modes of multiple indoor units.

[0068] In step S100, the multi-split air conditioner includes multiple indoor units. Different indoor units may be in different operating states. For example, 10 indoor units may be installed in 10 different rooms. If no one is in the first group of rooms, the indoor units in that group can be turned off. If the temperature in the second group of rooms has stabilized, the indoor units in that group can be in standby mode. If the temperature in the third group of rooms is too high, the indoor units need to operate in cooling mode. If the temperature in the fourth group of rooms is too low, the indoor units need to operate in heating mode. Of course, the indoor units in the third and fourth groups of rooms can operate in either cooling or heating mode simultaneously. It should be noted that when some indoor units are off, there may be refrigerant overload in the system. In this case, the refrigerant level in the system needs to be adjusted promptly to maintain stable system operation. However, multiple indoor units in operation may be in the same operating mode or different operating modes. In this case, the refrigerant level in the system cannot be adjusted according to a simple additive or decreasing relationship.

[0069] In step S200, if at least one of the multiple indoor units is determined to be in a stopped state (i.e., in a shutdown or standby state), the refrigerant system of the multi-split air conditioner may have an excess of refrigerant, leading to reduced air conditioning efficiency, high load on internal components, and sharp abnormal noises. Therefore, under this condition, a refrigerant overload detection operation should be performed promptly. It should be noted that refrigerant overload exhibits various external manifestations, appearing at multiple components of the system. Therefore, one or more of these external manifestations can be detected to confirm refrigerant overload. The appearance of any one of these external manifestations indicates the presence of refrigerant overload, thus requiring timely refrigerant control.

[0070] In step S300, it is determined that the refrigerant detection meets the preset conditions and continues for at least a first set time, such as more than 1 minute. At this time, the air conditioner may experience problems such as reduced operating efficiency, high load on internal components, and sharp abnormal noises. Therefore, it is necessary to run the refrigerant control program in a timely manner. The multi-split air conditioner provided in this embodiment of the invention may have multiple indoor units with different operating modes. When the indoor unit operating modes are different, the refrigerant quantity control in the system is more complex. Therefore, adopting corresponding refrigerant control programs for different operating modes of multiple indoor units is more targeted and the refrigerant quantity in the system is more stable.

[0071] According to one embodiment of the present invention, the step of running a corresponding refrigerant control program based on the operating modes of multiple indoor units specifically includes:

[0072] S310. If it is determined that multiple indoor units are running in cooling mode, the multi-split air conditioner is controlled to run the first refrigerant control program to adjust the amount of refrigerant in the system through the electronic expansion valve of the indoor unit that is in the off state.

[0073] S320: If it is determined that some of the multiple indoor units are operating in cooling mode and others in heating mode, then the multi-split air conditioner is controlled to run a second refrigerant control program to adjust the amount of refrigerant in the system through the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the off state.

[0074] In step S310, multiple indoor units are running in cooling mode. The excess refrigerant caused by the shut-down indoor unit can be adjusted by the electronic expansion valve of the shut-down indoor unit, for example, by opening a certain degree at intervals to keep the refrigerant in the system in a balanced state.

[0075] In step S320, some of the multiple indoor units operate in cooling mode and others operate in heating mode. At this time, the refrigerant situation in the system is different from that when all indoor units are operating in cooling mode. It is difficult to adjust the refrigerant by the electronic expansion valve of the indoor unit that is in the off state. Therefore, the amount of refrigerant in the system is adjusted by the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit that is in the off state.

[0076] In steps S310 and S320, for different operating conditions of multiple indoor units, the multi-split air conditioner adopts a corresponding refrigerant control program, which can make the amount of refrigerant in the system more in line with actual needs.

[0077] According to an embodiment of the present invention, the step of controlling the multi-split air conditioner to operate the first refrigerant control program specifically includes:

[0078] S311. Control the high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state to be in the closed state, and control the electronic expansion valve of the indoor unit in the shutdown state to open to the set opening degree at a second set time interval, and to completely close after a third set time interval.

[0079] In step S311, both the high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the off state are closed. At this time, the piping of the indoor unit in the standby state does not participate in the exchange of refrigerant in the system. The electronic expansion valve of the indoor unit in the off state is controlled to open to a set opening degree at a second set time interval and then completely close after a third set time interval. For example, the electronic expansion valve of the indoor unit is opened to 100pls every 15 minutes and then closed after 10 seconds. In this way, the refrigerant piping of the indoor unit in the standby state can be used as a container to balance the refrigerant quantity and refrigerant pressure, and the refrigerant quantity in the system can be periodically adjusted to avoid the refrigerant over-extension phenomenon in the system.

[0080] According to one embodiment of the present invention, the step of controlling the operation of the first refrigerant control program in a multi-split air conditioner further includes:

[0081] S312. During the period when the electronic expansion valve of the indoor unit in the shutdown state is opened to the set opening degree, the first temperature at the inlet of the indoor unit and the ambient temperature of the indoor unit are obtained.

[0082] S313. If the difference between the first temperature and the indoor unit ambient temperature is greater than or equal to the first set temperature, then control the multi-split air conditioner to perform refrigerant detection and subsequent steps.

[0083] S314. If the difference between the first temperature and the indoor unit ambient temperature is less than the first set temperature, then control the multi-split air conditioner to maintain the current operating state.

[0084] Steps S312 to S314 form a new cycle after step S310. During the period when the electronic expansion valve of the indoor unit in the shutdown state is opened to the set opening degree, the first temperature at the inlet of the current indoor unit and the indoor unit ambient temperature are obtained. For example, when the difference between the first temperature and the indoor unit ambient temperature is greater than or equal to 3°C, the refrigerant detection in step 200 and the contents of step S300 are re-executed. When the difference between the first temperature and the indoor unit ambient temperature is less than 3°C, the multi-split air conditioner is controlled to maintain the current operating state.

[0085] Therefore, steps S312 to S314 can form a dynamic cycle process, thereby enabling the multi-split air conditioner to maintain refrigerant balance throughout the entire operation.

[0086] According to an embodiment of the present invention, the steps of controlling the operation of the second refrigerant control program in a multi-split air conditioner specifically include:

[0087] S321. Control the electronic expansion valve of the indoor unit in the shutdown state, as well as the high-pressure gas pipe shut-off valve and low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state, to be closed, and control the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state to open for a fifth set time interval every fourth set time interval.

[0088] In step S321, the electronic expansion valve controlling the indoor unit in the off state, as well as the high-pressure gas pipe shut-off valve and low-pressure gas pipe shut-off valve of the reversing valve box connected to the off-state indoor unit, are all closed. At this time, the piping of the indoor unit in standby state does not participate in the exchange of refrigerant in the system. By periodically opening the high-pressure gas pipe shut-off valve of the reversing valve box, the amount and pressure of refrigerant in the system can be adjusted to avoid over-refrigerant.

[0089] According to one embodiment of the present invention, the step of controlling the operation of the second refrigerant control program in a multi-split air conditioner further includes:

[0090] S322. During the period when the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit is open while the indoor unit is in a stopped state, obtain the second temperature at the outlet of the current indoor unit and the ambient temperature of the indoor unit.

[0091] S323. If the difference between the second temperature and the indoor unit ambient temperature is greater than or equal to the second set temperature, then control the multi-split air conditioner to perform refrigerant detection and subsequent steps.

[0092] S324. If the difference between the second temperature and the indoor unit ambient temperature is less than the second set temperature, then control the multi-split air conditioner to maintain the current operating state.

[0093] Steps S322 to S324 form a new cycle after step S320. During the period when the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state is open, the second temperature at the outlet of the current indoor unit and the indoor unit ambient temperature are obtained. For example, when the difference between the second temperature and the indoor unit ambient temperature is greater than or equal to 3°C, the refrigerant detection in step 200 and the contents of step S300 are re-executed. When the difference between the second temperature and the indoor unit ambient temperature is less than 3°C, the multi-split air conditioner is controlled to maintain the current operating state.

[0094] Therefore, steps S322 to S324 can form a dynamic cycle process, thereby enabling the multi-split air conditioner to maintain refrigerant balance throughout the entire operation.

[0095] During the operation of a multi-split air conditioner, if at least one of the indoor units is in a stopped state (i.e., off or in standby), the refrigerant system may have an excess of refrigerant. This can lead to reduced operating efficiency, increased load on internal components, and sharp, abnormal noises. Therefore, it is crucial to perform a refrigerant overload detection procedure under these conditions. It should be noted that refrigerant overload exhibits various external symptoms, manifesting at multiple components within the system. Therefore, detecting one or more of these symptoms can confirm the overload. The appearance of any one of these symptoms indicates refrigerant overload, requiring immediate refrigerant control.

[0096] In this embodiment of the invention, the supercoolant detection includes the following situations:

[0097] In one embodiment, supercoolant detection includes:

[0098] S2011. Obtain the heat exchange temperature difference of each indoor unit in operation, and the exhaust superheat of the outdoor unit;

[0099] The conditions to be set include:

[0100] S2012, At least half of the indoor units in operation have a heat exchange temperature difference less than or equal to the target superheat temperature, and the exhaust superheat of the outdoor unit is less than or equal to the target exhaust superheat.

[0101] In step S2011, the heat exchange temperature difference of the indoor unit refers to the temperature difference between the second temperature at the outlet of the evaporator 20 and the first temperature at the inlet of the evaporator 20, wherein the superheat temperature is set to -1℃ and the target exhaust superheat is 10℃.

[0102] In another embodiment, the supercoolant detection includes:

[0103] S2021. Obtain the opening degree of the electronic expansion valve of each indoor unit that is in operation.

[0104] The setting conditions include:

[0105] S2021. At least half of the indoor units in operation have electronic expansion valves with an opening degree less than or equal to the set subcooling opening degree.

[0106] In step S2021, the opening degree of the electronic expansion valve 18 of each indoor unit in operation is obtained, wherein the subcooling opening degree is set to 90pls.

[0107] In another embodiment, the supercoolant detection includes:

[0108] S2031. Obtain the outdoor ambient temperature and the high-pressure saturation temperature of the outdoor unit.

[0109] The conditions to be set include:

[0110] S2032, the outdoor ambient temperature is greater than or equal to the set outdoor temperature, and the high pressure saturation temperature of the outdoor unit is greater than or equal to the set saturation temperature.

[0111] In step S2032, the outdoor temperature can be set to 40°C and the saturation temperature can be set to 58°C.

[0112] The control device for a multi-split air conditioner according to a second aspect embodiment of the present invention is described in the following reference. Figure 5 ,include:

[0113] The acquisition module 200 is used to acquire the working status and operating mode of multiple indoor units.

[0114] The first execution module 210 is used to determine if at least one of the multiple indoor units is in a stopped state, and then perform a refrigerant detection.

[0115] The second execution module 220 is used to determine that the refrigerant detection meets the set conditions and lasts for at least a first set time, and then runs the corresponding refrigerant control program according to the operating mode of multiple indoor units.

[0116] It should be noted that steps S100, S200, and S300, as well as other steps, are merely for ease of description and do not constitute a temporal limitation on the steps in the control method for multi-split air conditioners. Furthermore, some content is described in detail in the control method for multi-split air conditioners provided in the first aspect embodiment, and all content in the control method for multi-split air conditioners is also applicable to the control device for multi-split air conditioners provided in the second aspect embodiment. Therefore, to avoid repetition, the control device for multi-split air conditioners provided in the second aspect embodiment is not described in detail. Similarly, the content in the above two aspects embodiments can be used to explain the content of all subsequent aspects embodiments; therefore, repeated content will not be described in the following embodiments. The technical effects of the control device for multi-split air conditioners provided according to the embodiments of the present invention correspond to the technical effects of the above-described control method for multi-split air conditioners, and will not be repeated here.

[0117] A multi-split 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, characterized in that the processor executes the program to implement a control method for the multi-split air conditioner according to a first aspect of the present invention.

[0118] When a multi-split air conditioner is running: It acquires the operating status and mode of multiple indoor units; if at least one of the indoor units is in a stopped state, it performs a refrigerant overload detection; if the refrigerant overload detection meets set conditions and lasts for at least a first set duration, it runs the corresponding refrigerant overload control program according to the operating mode of the multiple indoor units. When some indoor units of a multi-split air conditioner are in a stopped state, there may be excessive refrigerant in the refrigerant circulation system. Therefore, a refrigerant overload detection is performed promptly. If the refrigerant overload detection meets set conditions and lasts for at least a first set duration, it indicates that there is excessive refrigerant in the system. The corresponding refrigerant overload control program is determined through the operating modes of the multiple indoor units to adjust the refrigerant level in the system in a timely manner, maintain the stability of the refrigerant level in the system, thereby improving the operating efficiency of the air conditioner, reducing the load on internal components such as the compressor, and reducing system noise. It should be noted that the multiple indoor units of the multi-split air conditioner provided in this embodiment of the invention may have different operating modes. When the indoor units operate in different modes, the control of the refrigerant quantity in the system becomes more complex. Therefore, adopting corresponding refrigerant control programs for different operating modes of multiple indoor units is more targeted and the refrigerant quantity in the system is more stable.

[0119] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a multi-split air conditioner, characterized in that, The multi-split air conditioner includes multiple indoor units, and the control method for the multi-split air conditioner includes: Obtain the working status and operating mode of multiple indoor units; If at least one of the indoor units is determined to be in a stopped state, a refrigerant detection is performed. If it is determined that the refrigerant detection meets the set conditions and lasts for at least a first set time, then the corresponding refrigerant control program is run according to the operating modes of the multiple indoor units. The supercoolant detection includes: The heat exchange temperature difference of each of the indoor units in operation, and the exhaust superheat of the outdoor unit are obtained. The setting conditions include: At least half of the indoor units in operation have a heat exchange temperature difference less than or equal to the target superheat temperature, and the exhaust superheat of the outdoor unit is less than or equal to the target exhaust superheat. or, The supercoolant detection includes: Obtain the opening degree of the electronic expansion valve of each of the indoor units in operation; The setting conditions include: At least half of the indoor units in operation have electronic expansion valves with an opening degree less than or equal to the set subcooling opening degree; or, The supercoolant detection includes: Obtain 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 the set outdoor temperature, and the high-pressure saturation temperature of the outdoor unit is greater than or equal to the set saturation temperature.

2. The control method for a multi-split air conditioner according to claim 1, characterized in that, The step of running the corresponding refrigerant control program according to the operating modes of the multiple indoor units specifically includes: If it is determined that all the indoor units are running in cooling mode, then the multi-split air conditioner is controlled to run the first refrigerant control program to adjust the amount of refrigerant in the system through the electronic expansion valve of the indoor unit in the off state; If it is determined that some of the multiple indoor units operate in cooling mode and others in heating mode, then the multi-split air conditioner is controlled to run a second refrigerant control program to adjust the amount of refrigerant in the system through the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the off state.

3. The control method for a multi-split air conditioner according to claim 2, characterized in that, The steps of controlling the multi-split air conditioner to operate the first refrigerant control program specifically include: The high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state are both closed. The electronic expansion valve of the indoor unit in the shutdown state is controlled to open to a set opening degree at a second set time interval, and then completely close after a third set time interval.

4. The control method for a multi-split air conditioner according to claim 3, characterized in that, The step of controlling the multi-split air conditioner to operate the first refrigerant control program further includes: During the period when the electronic expansion valve of the indoor unit is in the shutdown state is opened to a set opening degree, the first temperature at the inlet of the evaporator of the current indoor unit and the indoor unit ambient temperature are obtained. If the difference between the first temperature and the indoor unit ambient temperature is greater than or equal to the first set temperature, then the multi-split air conditioner is controlled to perform refrigerant detection and subsequent steps. If the difference between the first temperature and the indoor unit ambient temperature is less than the first set temperature, then the multi-split air conditioner is controlled to maintain its current operating state.

5. The control method for a multi-split air conditioner according to claim 2, characterized in that, The steps of controlling the operation of the second refrigerant control program in the multi-split air conditioner specifically include: The electronic expansion valve of the indoor unit in the shutdown state, as well as the high-pressure gas pipe shut-off valve and the low-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state, are all kept closed. The high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit in the shutdown state is opened for a fifth set time interval every fourth set time interval.

6. The control method for a multi-split air conditioner according to claim 5, characterized in that, The step of controlling the operation of the second refrigerant control program in the multi-split air conditioner further includes: During the period when the high-pressure gas pipe shut-off valve of the reversing valve box connected to the indoor unit is open while the indoor unit is in a shutdown state, the second temperature at the outlet of the evaporator of the current indoor unit and the indoor unit ambient temperature are obtained. If the difference between the second temperature and the indoor unit ambient temperature is greater than or equal to the second set temperature, then the multi-split air conditioner is controlled to perform refrigerant detection and subsequent steps. If the difference between the second temperature and the indoor unit ambient temperature is less than the second set temperature, the multi-split air conditioner is controlled to maintain its current operating state.

7. A control device for a multi-split air conditioner, characterized in that, include: The acquisition module is used to acquire the working status and operating mode of multiple indoor units; The first execution module is used to determine if at least one of the multiple indoor units is in a shutdown state, and then perform a refrigerant detection. 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 then runs the corresponding refrigerant control program according to the operating modes of the multiple indoor units. The supercoolant detection includes: The heat exchange temperature difference of each of the indoor units in operation, and the exhaust superheat of the outdoor unit are obtained. The setting conditions include: At least half of the indoor units in operation have a heat exchange temperature difference less than or equal to the target superheat temperature, and the exhaust superheat of the outdoor unit is less than or equal to the target exhaust superheat. or, The supercoolant detection includes: Obtain the opening degree of the electronic expansion valve of each of the indoor units in operation; The setting conditions include: At least half of the indoor units in operation have electronic expansion valves with an opening degree less than or equal to the set subcooling opening degree; or, The supercoolant detection includes: Obtain 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 the set outdoor temperature, and the high-pressure saturation temperature of the outdoor unit is greater than or equal to the set saturation temperature.

8. A multi-split air conditioner, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the control method for a multi-split air conditioner as described in any one of claims 1 to 6.

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