Control methods, control devices, and multi-split air conditioners

Abstract

This invention relates to the field of air conditioner technology, providing a control method, control device, and multi-split air conditioner. The multi-split air conditioner includes a refrigerant circulation loop consisting of a compressor, an outdoor heat exchanger, a first electronic expansion valve, and an indoor heat exchanger connected by refrigerant piping. A gas-liquid separator is installed on the refrigerant piping between the compressor's suction port and the indoor heat exchanger. One end of a branch line connects to the refrigerant piping between the indoor heat exchanger and the gas-liquid separator, and the other end connects to the refrigerant piping between the outdoor heat exchanger and the first electronic expansion valve. A second electronic expansion valve is installed on the branch line. A liquid line pressure sensor is installed on the refrigerant piping between the outdoor heat exchanger and the first electronic expansion valve to detect the liquid line pressure. By diverting a portion of the high-pressure refrigerant in the liquid line into the gas-liquid separator through the branch line, the liquid line pressure is reduced, preventing overpressure of the refrigerant in the liquid line under high external temperatures and improving the safety of the liquid line.

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] With the widespread use of air conditioners, multi-split air conditioning systems are commonly used for temperature control in factories, shopping malls, and commercial office buildings. These systems allow for centralized temperature control of a large work area, offering convenience. However, in practice, multi-split air conditioners often have indoor units installed higher than the outdoor units. When the system is turned off, some of the refrigerant in the multiple indoor units and long piping flows back to the outdoor unit, while the remainder is stored in the liquid line. When the ambient temperature rises, this can cause the refrigerant stored in the liquid line to vaporize, leading to a rapid increase in pressure. This pressure may exceed the maximum design pressure of the liquid line, causing it to rupture and severely compromising the safety and stability of the air conditioner. 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 multi-split air conditioner, in which a branch is provided on the liquid pipe between the outdoor heat exchanger and the indoor heat exchanger. The other end of the branch is connected to a gas-liquid separator. Under certain liquid pipe pressure conditions, a portion of the refrigerant in the liquid pipe can be introduced into the gas-liquid separator, preventing the refrigerant in the liquid pipe from becoming overpressured in the high-temperature environment, thus improving the safety of the liquid pipe and the multi-split air conditioner.

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

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

[0006] The present invention also provides a multi-split air conditioner.

[0007] According to a first aspect embodiment of the present invention, a multi-split air conditioner includes:

[0008] A refrigerant circulation loop consisting of at least a compressor, an outdoor heat exchanger, a first electronic expansion valve, and an indoor heat exchanger connected by refrigerant piping;

[0009] A gas-liquid separator is installed on the refrigerant pipeline between the compressor's suction port and the indoor heat exchanger;

[0010] A branch line is provided, one end of which is connected to the inlet of the gas-liquid separator, and the other end is connected to the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve. A second electronic expansion valve is provided on the branch line.

[0011] A liquid line pressure sensor is installed on the refrigerant line between the outdoor heat exchanger and the first electronic expansion valve to detect the liquid line pressure.

[0012] The controller is electrically connected to the first electronic expansion valve, the second electronic expansion valve, and the liquid line pressure sensor. The controller is configured to adjust the opening of the second electronic expansion valve to a target opening based on the liquid line pressure when a shutdown signal is received.

[0013] According to one embodiment of the present invention, it further includes:

[0014] A plate heat exchanger includes a first heat exchange inlet, a first heat exchange outlet, a second heat exchange inlet, and a second heat exchange outlet. The first heat exchange inlet is connected to the outdoor heat exchanger, the first heat exchange outlet is connected to the first electronic expansion valve, the second heat exchange inlet is connected to the first heat exchange outlet, the second heat exchange outlet is connected to the inlet of the gas-liquid separator, and the second electronic expansion valve is disposed on the refrigerant pipeline between the first heat exchange outlet and the second heat exchange inlet.

[0015] According to one embodiment of the present invention, a bypass branch is provided between the intake port and the exhaust port of the compressor, and a solenoid valve is provided on the bypass branch, the solenoid valve being electrically connected to the controller.

[0016] A control method for a multi-split air conditioner according to a second aspect embodiment of the present invention includes:

[0017] Upon receiving a shutdown signal, the liquid pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve is acquired, and the real-time pressure status of the liquid pipeline is determined based on the liquid pressure and a predetermined state relationship; wherein, the real-time pressure status includes an overpressure state and a low pressure state.

[0018] When the real-time pressure state is the overpressure state, a first target opening degree is determined according to the liquid pipe pressure and the first adjustment relationship, and a signal is issued to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

[0019] According to one embodiment of the present invention, the step of determining the real-time pressure state of the liquid pipe based on the liquid pipe pressure and a predetermined state relationship further includes:

[0020] When the real-time pressure state is the low-pressure state, a second target opening degree is determined according to the liquid pipe pressure and the second adjustment relationship, and a signal is issued to adjust the opening degree of the second electronic expansion valve to the second target opening degree; wherein, the second target opening degree is less than the current opening degree of the second electronic expansion valve.

[0021] According to an embodiment of the present invention, the step of determining the first target opening degree based on the liquid pipe pressure and the first adjustment relationship specifically includes:

[0022] Obtain the adjustment coefficient and adjustment function corresponding to the first adjustment relationship, and determine the difference between the liquid pipe pressure and the preset liquid pipe pressure;

[0023] The first target opening degree is determined based on the difference, the adjustment coefficient, and the adjustment function.

[0024] According to an embodiment of the present invention, when the real-time pressure state is the overpressure state, the control method further includes:

[0025] Determine the relationship between the liquid pipe pressure and the predetermined pressure threshold;

[0026] When the pressure in the liquid pipe is greater than or equal to the predetermined pressure threshold, a signal is sent to control the solenoid valve to open.

[0027] According to one embodiment of the present invention, when a power-off signal is received, the control method further includes:

[0028] Obtain the power-on status of the multi-split air conditioner;

[0029] When the multi-split air conditioner is in a power-off state, it sends a signal to adjust the opening of the second electronic expansion valve to the normally open position.

[0030] A control device for a multi-split air conditioner according to a third aspect embodiment of the present invention includes:

[0031] The acquisition module is used to acquire the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve when a shutdown signal is received, and to determine the real-time pressure status of the liquid pipe based on the liquid pipe pressure and a predetermined state relationship; wherein, the real-time pressure status includes an overpressure state and a low pressure state.

[0032] The signal transmitting module is used to determine a first target opening degree based on the liquid pipe pressure and a first adjustment relationship when the real-time pressure state is the overpressure state, and to send a signal to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

[0033] A multi-split air conditioner according to a fourth 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 steps of the control method for a multi-split air conditioner according to a second aspect of the present invention.

[0034] The above-described one or more technical solutions of this invention have at least one of the following technical effects:

[0035] The multi-split air conditioner provided according to an embodiment of the present invention includes a compressor, an outdoor heat exchanger, a first electronic expansion valve, an indoor heat exchanger, a gas-liquid separator, and a branch circuit. The compressor, outdoor heat exchanger, first electronic expansion valve, and indoor heat exchanger are connected to form a refrigerant circulation loop through refrigerant pipelines. The gas-liquid separator is disposed on the refrigerant pipeline between the compressor's suction port and the indoor heat exchanger. One end of the branch circuit is connected to the inlet of the gas-liquid separator, and the other end is connected to the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve. A second electronic expansion valve is disposed on the branch circuit. A liquid line pressure sensor is disposed on the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve for detecting liquid line pressure. A controller is electrically connected to the first electronic expansion valve, the second electronic expansion valve, and the liquid line pressure sensor. The controller is configured to adjust the opening degree of the second electronic expansion valve to a target opening degree according to the liquid line pressure when a shutdown signal is received. When the real-time pressure in the liquid pipe is in an overpressure state, a first target opening degree is determined based on the liquid pipe pressure and the first adjustment relationship, and a signal is sent to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve. By introducing a portion of the high-pressure refrigerant in the liquid pipe into the gas-liquid separator through a branch, the refrigerant storage space is increased, the pressure of the refrigerant in the liquid pipe is reduced, and the overpressure state of the refrigerant in the liquid pipe is prevented in the high-temperature environment, thereby improving the safety of the liquid pipe and the multi-split air conditioner. Attached Figure Description

[0036] 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.

[0037] Figure 1 This is a schematic structural diagram of a multi-split air conditioner provided in an embodiment of the present invention;

[0038] Figure 2 A flowchart of a control method for a multi-split air conditioner provided in an embodiment of the present invention;

[0039] Figure 3 A schematic structural diagram of the control device for a multi-split air conditioner provided in an embodiment of the present invention;

[0040] Figure 4 This is a schematic structural diagram of the electronic equipment of a multi-split air conditioner provided in an embodiment of the present invention.

[0041] Figure label:

[0042] 11. Compressor; 12. Outdoor heat exchanger; 14. Indoor heat exchanger; 15. Gas-liquid separator; 16. Flow branch; 17. Second electronic expansion valve; 18. Liquid line pressure sensor; 19. Plate heat exchanger; 20. Bypass branch; 21. Solenoid valve;

[0043] 301. Acquisition module; 302. Signal transmission module. Detailed Implementation

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] In related technologies, during the actual installation and use of multi-split air conditioners, the indoor units are often installed higher than the outdoor units. When the multi-split air conditioner is turned off, some of the refrigerant in the multiple indoor units and long piping flows back to the outdoor unit, while the rest flows back and is stored in the liquid line. When the ambient temperature rises, the refrigerant stored in the liquid line will vaporize, causing the pressure inside the liquid line to rise rapidly. This pressure may exceed the maximum design pressure of the liquid line, leading to its rupture, which seriously affects the safety and stability of the air conditioner.

[0050] Please refer to the multi-split air conditioner provided according to the first aspect embodiment of the present invention. Figure 1 It includes a compressor 11, an outdoor heat exchanger 12, a first electronic expansion valve, an indoor heat exchanger 14, a gas-liquid separator 15, a branch line 16, a liquid pipe pressure sensor 18, and a controller, etc.

[0051] The compressor 11, outdoor heat exchanger 12, first electronic expansion valve and indoor heat exchanger 14 are connected by refrigerant pipeline to form a refrigerant circulation loop. The refrigerant circulation loop may also be equipped with a four-way valve, liquid pipe shut-off valve, gas pipe shut-off valve and multiple sensors.

[0052] In the multi-split air conditioner provided in this embodiment of the invention, multiple indoor units are connected in parallel. Each indoor unit includes an indoor heat exchanger 14 and an indoor unit expansion valve. The indoor unit expansion valve can serve as the first electronic expansion valve in the refrigerant circulation loop. Figure 1 Not shown in the image, each indoor unit can be controlled independently.

[0053] A gas-liquid separator 15 is installed on the refrigerant pipeline between the suction port of the compressor 11 and the indoor heat exchanger 14. The gas-liquid separator 15 has a space for storing liquid refrigerant. During normal operation, the gas-liquid separator 15 filters the refrigerant before the suction port of the compressor 11, retaining the liquid refrigerant in the gas-liquid separator 15 and allowing the gaseous refrigerant to enter the suction port of the compressor 11. This prevents liquid slugging in the compressor 11 and improves the safety of the compressor 11.

[0054] In this embodiment of the invention, the multi-split air conditioner further includes a branch line 16. One end of the branch line 16 is connected to the inlet of the gas-liquid separator 15, and the other end is connected to the refrigerant pipeline between the outdoor heat exchanger 12 and the first electronic expansion valve. A second electronic expansion valve 17 is installed on the branch line 16. Adjusting the opening of the second electronic expansion valve 17 allows some refrigerant to flow into the gas-liquid separator 15 along the branch line 16. A liquid line pressure sensor 18 is installed on the refrigerant pipeline between the outdoor heat exchanger 12 and the first electronic expansion valve to detect the liquid line pressure.

[0055] The controller is electrically connected to the first electronic expansion valve 17, the second electronic expansion valve 17, and the liquid line pressure sensor 18. The controller is configured to adjust the opening of the second electronic expansion valve 17 to a target opening based on the liquid line pressure when a shutdown signal is received. For details regarding adjusting the opening of the second electronic expansion valve 17 to the target opening based on the liquid line pressure upon receiving a shutdown signal, please refer to the description of the control method for a multi-split air conditioner in the second aspect embodiment of the present invention.

[0056] In the multi-split air conditioner provided in this embodiment of the invention, when the real-time pressure state in the liquid pipe is overpressured, a first target opening degree is determined based on the liquid pipe pressure and a first adjustment relationship, and a signal is issued to adjust the opening degree of the second electronic expansion valve 17 to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve 17. By introducing a portion of the high-pressure refrigerant in the liquid pipe into the gas-liquid separator 15 through the diversion branch 16, the refrigerant storage space is increased, the pressure of the refrigerant in the liquid pipe is reduced, and overpressure is avoided in the liquid pipe under high external temperatures, thus improving the safety of the liquid pipe and the multi-split air conditioner.

[0057] In some embodiments, the multi-split air conditioner includes a plate heat exchanger 19, which includes a first heat exchange inlet, a first heat exchange outlet, a second heat exchange inlet, and a second heat exchange outlet. The first heat exchange inlet is connected to the outdoor heat exchanger 12 via a refrigerant pipeline, the first heat exchange outlet is connected to a first electronic expansion valve via a refrigerant pipeline, the second heat exchange inlet is connected to the first heat exchange outlet via a refrigerant pipeline, and the second heat exchange outlet is connected to the inlet of the gas-liquid separator 15 via a refrigerant pipeline. The second electronic expansion valve 17 is disposed on the refrigerant pipeline between the first heat exchange outlet and the second heat exchange inlet.

[0058] Please see Figure 1In the multi-split air conditioner provided in this embodiment of the invention, the branch circuit 16 is an enthalpy-increasing branch. When the multi-split air conditioner is working normally, opening the second electronic expansion valve 17 allows a portion of the refrigerant to evaporate and absorb heat in the plate heat exchanger 19. This keeps the refrigerant flowing to the indoor heat exchanger 14 in a subcooled state. The evaporated refrigerant absorbs heat and then enters the compressor 11, improving the heat exchange efficiency of the indoor heat exchanger 14 and increasing the cooling and heating power of the compressor 11. When the multi-split air conditioner is turned off, the enthalpy-increasing branch (branch circuit 16) is open, allowing a portion of the refrigerant in the liquid pipe between the outdoor heat exchanger 12 and the indoor heat exchanger 14 to be introduced into the gas-liquid separator 15. This fully utilizes the storage space within the gas-liquid separator 15, thereby preventing overpressure of the refrigerant in the liquid pipe under high external temperatures and improving the safety of the liquid pipe.

[0059] When the multi-split air conditioner is turned off, the liquid pipe is depressurized through the enthalpy-increasing branch and the refrigerant is temporarily stored through the gas-liquid separator 15. The enthalpy-increasing branch and the gas-liquid separator 15 are existing structures of multi-split air conditioners. The liquid pipe depressurization and refrigerant collection can be achieved without setting up an additional refrigerant collection device, which reduces the operating cost of multi-split air conditioners.

[0060] In some embodiments, a bypass branch 20 is provided between the intake port and the exhaust port of the compressor 11, and a solenoid valve 21 is provided on the bypass branch 20. The solenoid valve 21 is electrically connected to the controller.

[0061] Please see Figure 1 A bypass branch 20 is provided between the suction port and the discharge port of the compressor 11, and a solenoid valve 21 is installed on the bypass branch 20. When the multi-split air conditioner is turned off, if opening the second electronic expansion valve 17 is still insufficient to relieve pressure in the liquid line, then opening the solenoid valve 21 can be considered. Figure 1 It can be seen that after opening solenoid valve 21, the refrigerant pipeline between outdoor heat exchanger 12 and compressor 11 discharge port, the bypass branch 20, and the refrigerant pipeline between bypass branch 20 and gas-liquid separator 15 can all become potential refrigerant storage locations. Therefore, the refrigerant pressure in the liquid pipeline can be further reduced, improving the safety of the liquid pipeline. The controller is electrically connected to solenoid valve 21 and is configured to open solenoid valve 21 when the liquid pipeline pressure meets a predetermined pressure threshold. The liquid pipeline pressure required for solenoid valve 21 to open is greater than the liquid pipeline pressure when the second solenoid valve 21 adjusts its opening.

[0062] In some embodiments, the refrigerant circulation loop further includes a liquid line shut-off valve and a gas line shut-off valve, both of which are electrically connected to the controller. When the multi-split air conditioner is turned off, the liquid line shut-off valve and the gas line shut-off valve can be controlled to be in the closed state, sealing a portion of the refrigerant inside the indoor heat exchanger 14, preventing all the refrigerant from flowing to the liquid line and the outdoor heat exchanger 12, thereby reducing the liquid line pressure.

[0063] For the control method of a multi-split air conditioner provided according to the second aspect embodiment of the present invention, please refer to [link to relevant documentation]. Figure 2 ,include:

[0064] S200: Upon receiving a shutdown signal, acquire the liquid pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve, and determine the real-time pressure status of the liquid pipeline based on the liquid pressure and a predetermined state relationship; wherein, the real-time pressure status includes overpressure status and low pressure status.

[0065] Understandably, in response to a shutdown signal, a multi-split air conditioner does not immediately cut off power. Instead, it uses stored energy or mains power to adjust each component to its initial state or prepare it for the next startup. Liquid line pressure is acquired via a liquid line pressure sensor, and the real-time pressure state is determined based on this pressure and a predetermined state relationship. This predetermined relationship includes pressure thresholds, the correspondence between pressure zones and pressure states, etc. For example, if the liquid line pressure is greater than or equal to the pressure threshold, the real-time pressure state is considered overpressure.

[0066] S220. When the real-time pressure is in an overpressure state, a first target opening degree is determined based on the liquid pipe pressure and the first adjustment relationship, and a signal is sent to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

[0067] It is understandable that when the real-time pressure is overpressured, the liquid pipe is in an unsafe state. The ambient temperature is high, and different pipe fittings may crack due to differences in their coefficients of thermal expansion and contraction. The liquid pipe may also burst under overpressure, leading to safety accidents. In this embodiment of the invention, when the real-time pressure is overpressured, a first target opening is determined based on the liquid pipe pressure and a first adjustment relationship. Then, the second electronic expansion valve is adjusted to the first target opening. The first target opening is greater than the current opening of the second electronic expansion valve, allowing some of the refrigerant in the liquid pipe to gradually flow into the gas-liquid separator. Simultaneously, if the liquid pipe pressure is high, the opening adjustment range of the second electronic expansion valve is also larger to achieve rapid adjustment of the liquid pipe pressure, quickly reducing the refrigerant pressure in the liquid pipe and ensuring the immediacy of liquid pipe pressure adjustment.

[0068] In some embodiments, the step of determining the first target opening degree based on the liquid line pressure and the first adjustment relationship specifically includes:

[0069] Obtain the adjustment coefficient and adjustment function corresponding to the first adjustment relationship, and determine the difference between the liquid pipe pressure and the preset liquid pipe pressure.

[0070] The first target opening degree is determined based on the difference, adjustment coefficient, and adjustment function.

[0071] It is understandable that the first target opening determined based on the liquid pipe pressure and the first adjustment relationship has a positive correlation. For example, if the liquid pipe pressure is high, the opening adjustment range of the second electronic expansion valve will also be large, so as to achieve rapid adjustment of the liquid pipe pressure, reduce the refrigerant pressure in the liquid pipe as soon as possible, and thus ensure the immediacy of the liquid pipe pressure adjustment.

[0072] For example, when the liquid pipe pressure is greater than (p) bar, the operating opening of the second electronic expansion valve increases from (c) pls to (u) pls, and the first adjustment relationship conforms to the target formula: lev=(c) pls+Δp*a.

[0073] In some embodiments, p is 20, c is 80, and u is 410, satisfying a linear adjustment relationship, thereby ensuring the proportionality of the liquid pipe pressure regulation.

[0074] In some embodiments, the step of determining the real-time pressure state of the liquid line based on the liquid line pressure and a predetermined state relationship further includes:

[0075] S240. When the real-time pressure is low, determine the second target opening degree based on the liquid pipe pressure and the second regulation relationship, and issue a signal to adjust the opening degree of the second electronic expansion valve to the second target opening degree; wherein, the second target opening degree is less than the current opening degree of the second electronic expansion valve.

[0076] Understandably, when the real-time pressure is low, the opening of the second expansion valve can be adjusted to the second target opening. This will maintain the stability of the liquid line pressure and prepare for the next startup.

[0077] In some embodiments, when the real-time pressure state is an overpressure state, the control method for a multi-split air conditioner further includes:

[0078] Determine the relationship between the liquid line pressure and the predetermined pressure threshold.

[0079] When the pressure in the liquid line is greater than or equal to a predetermined pressure threshold, a signal is sent to open the solenoid valve.

[0080] Please see Figure 1 A bypass branch is installed between the compressor's suction and discharge ports, and a solenoid valve is installed on this bypass branch. When the multi-split air conditioner is turned off, if opening the second electronic expansion valve is still insufficient to relieve pressure in the liquid line, then opening the solenoid valve can be considered. Figure 1It can be seen that after the solenoid valve is opened, the refrigerant lines between the outdoor heat exchanger and the compressor discharge port, the bypass branch, and the refrigerant lines between the bypass branch and the gas-liquid separator can all become potential refrigerant storage locations. Therefore, the refrigerant pressure in the liquid line can be further reduced, improving the safety of the liquid line. The controller is electrically connected to the solenoid valve and is configured to open the solenoid valve when the liquid line pressure meets a predetermined pressure threshold. The liquid line pressure required for the solenoid valve to open is greater than the liquid line pressure when the second solenoid valve adjusts its opening.

[0081] In some embodiments, the control method for a multi-split air conditioner upon receiving a shutdown signal further includes:

[0082] S210, Obtain the power-on status of the multi-split air conditioner;

[0083] S250: When the multi-split air conditioner is in a power-off state, it sends a signal to adjust the opening of the second electronic expansion valve to the normally open position.

[0084] Understandably, when the power supply system suddenly fails, the multi-split air conditioner will also generate a shutdown signal and use the energy stored in the battery module to complete the shutdown action. Upon receiving the shutdown signal, the power-on status of the multi-split air conditioner can be checked first. Here, power-on status refers to the electrical connection status between the multi-split air conditioner and the external circuit. If the multi-split air conditioner is in a normal power-on state, steps S200, S220, and S240 are completed; if the multi-split air conditioner is in a power-off state, step S250 is completed, preparing for subsequent startup.

[0085] The control device for a multi-split air conditioner according to a third aspect embodiment of the present invention is described in the following reference. Figure 3 ,include:

[0086] The acquisition module 301 is used to acquire the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve when a shutdown signal is received, and to determine the real-time pressure status of the liquid pipe according to the liquid pipe pressure and a predetermined state relationship; wherein, the real-time pressure status includes overpressure status and low pressure status.

[0087] The signal transmitting module 302 is used to determine a first target opening degree based on the liquid pipe pressure and the first adjustment relationship when the real-time pressure state is overpressure state, and to send a signal to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

[0088] It should be noted that steps S200 to S220 and other steps are for ease of description only and do not constitute a time sequence limitation for the steps in the control method of a multi-split air conditioner. Furthermore, some content is described in detail in the control method of a multi-split air conditioner provided in the second aspect embodiment, and all content in the control method of a multi-split air conditioner can also be applied to the control device of a multi-split air conditioner provided in the third aspect embodiment. Therefore, to avoid repetition, the control device of a multi-split air conditioner provided in the third 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 of a multi-split air conditioner provided according to the embodiments of the present invention correspond to the technical effects of the above-described control method of a multi-split air conditioner, and will not be described again here.

[0089] A multi-split air conditioner according to a fourth 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 steps of the control method for a multi-split air conditioner according to a second aspect of the present invention.

[0090] Figure 4 A schematic diagram illustrating the physical structure of an electronic device for a multi-split air conditioner is provided. This electronic device may include a processor 810, a communication interface 820, a memory 830, and a communication bus 840. The processor 810, communication interface 820, and memory 830 communicate with each other via the communication bus 840. The processor 810 can call logical instructions stored in the memory 830 to execute a control method for the multi-split air conditioner. This method includes: upon receiving a shutdown signal, acquiring the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve, and determining the real-time pressure state of the liquid pipe based on the liquid pipe pressure and a predetermined state relationship; wherein the real-time pressure state includes an overpressure state and a low pressure state; when the real-time pressure state is an overpressure state, determining a first target opening degree based on the liquid pipe pressure and a first adjustment relationship, and issuing a signal to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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 multi-split air conditioner, characterized in that, include: A refrigerant circulation loop consisting of at least a compressor, an outdoor heat exchanger, a first electronic expansion valve, and an indoor heat exchanger connected by refrigerant piping; A gas-liquid separator is installed on the refrigerant pipeline between the compressor's suction port and the indoor heat exchanger; A branch line is provided, one end of which is connected to the inlet of the gas-liquid separator, and the other end is connected to the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve. A second electronic expansion valve is provided on the branch line. A liquid line pressure sensor is installed on the refrigerant line between the outdoor heat exchanger and the first electronic expansion valve to detect the liquid line pressure. A controller is electrically connected to the first electronic expansion valve, the second electronic expansion valve, and the liquid line pressure sensor. The controller is configured to adjust the opening of the second electronic expansion valve to a target opening based on the liquid line pressure when a shutdown signal is received. It also includes: a plate heat exchanger, the plate heat exchanger including a first heat exchange inlet, a first heat exchange outlet, a second heat exchange inlet and a second heat exchange outlet, the first heat exchange inlet being connected to the outdoor heat exchanger, the first heat exchange outlet being connected to the first electronic expansion valve, the second heat exchange inlet being connected to the first heat exchange outlet, the second heat exchange outlet being connected to the inlet of the gas-liquid separator, and the second electronic expansion valve being disposed on the refrigerant pipeline between the first heat exchange outlet and the second heat exchange inlet.

2. The multi-split air conditioner according to claim 1, characterized in that, A bypass branch is provided between the air intake and exhaust ports of the compressor, and a solenoid valve is provided on the bypass branch. The solenoid valve is electrically connected to the controller.

3. A control method for a multi-split air conditioner as described in claim 1 or 2, characterized in that, include: Upon receiving a shutdown signal, the liquid pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve is acquired, and the real-time pressure status of the liquid pipeline is determined based on the liquid pressure and a predetermined state relationship; wherein, the real-time pressure status includes an overpressure state and a low pressure state. When the real-time pressure state is the overpressure state, a first target opening degree is determined according to the liquid pipe pressure and the first adjustment relationship, and a signal is issued to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

4. The control method for a multi-split air conditioner according to claim 3, characterized in that, The step of determining the real-time pressure state of the liquid pipe based on the liquid pipe pressure and the predetermined state relationship further includes: When the real-time pressure state is the low-pressure state, a second target opening degree is determined according to the liquid pipe pressure and the second adjustment relationship, and a signal is issued to adjust the opening degree of the second electronic expansion valve to the second target opening degree; wherein, the second target opening degree is less than the current opening degree of the second electronic expansion valve.

5. The control method for a multi-split air conditioner according to claim 3, characterized in that, The step of determining the first target opening degree based on the liquid pipe pressure and the first adjustment relationship specifically includes: Obtain the adjustment coefficient and adjustment function corresponding to the first adjustment relationship, and determine the difference between the liquid pipe pressure and the preset liquid pipe pressure; The first target opening degree is determined based on the difference, the adjustment coefficient, and the adjustment function.

6. The control method for a multi-split air conditioner according to claim 3, characterized in that, A bypass branch is provided between the air intake and exhaust ports of the compressor, and a solenoid valve is provided on the bypass branch. The solenoid valve is electrically connected to the controller. When the real-time pressure state is the overpressure state, the control method further includes: Determine the relationship between the liquid pipe pressure and the predetermined pressure threshold; When the pressure in the liquid pipe is greater than or equal to the predetermined pressure threshold, a signal is sent to control the solenoid valve to open.

7. The control method for a multi-split air conditioner according to claim 3, characterized in that, Upon receiving a power-off signal, the control method further includes: Obtain the power-on status of the multi-split air conditioner; When the multi-split air conditioner is in a power-off state, it sends a signal to adjust the opening of the second electronic expansion valve to the normally open position.

8. A control device for a multi-split air conditioner, characterized in that, The multi-split air conditioner as described in claim 1 or 2 includes: The acquisition module is used to acquire the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve when a shutdown signal is received, and to determine the real-time pressure status of the liquid pipe based on the liquid pipe pressure and a predetermined state relationship; wherein, the real-time pressure status includes an overpressure state and a low pressure state. The signal transmitting module is used to determine a first target opening degree based on the liquid pipe pressure and the first adjustment relationship when the real-time pressure state is the overpressure state, and to send a signal to adjust the opening degree of the second electronic expansion valve to the first target opening degree; wherein, the first target opening degree is greater than the current opening degree of the second electronic expansion valve.

9. 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 steps of the control method for a multi-split air conditioner as described in any one of claims 3 to 7.

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