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

Abstract

The invention relates to the technical field of air conditioners, and provides a control method and device of a multi-split air conditioner and the multi-split air conditioner. The multi-split air conditioner comprises a refrigerant circulation loop formed by connecting a compressor, an outdoor heat exchanger, a first electronic expansion valve and an indoor heat exchanger through a refrigerant pipeline; the gas-liquid separator is arranged on a refrigerant pipeline between an air suction port of the compressor and the indoor heat exchanger; one end of the shunting branch is communicated with the refrigerant pipeline between the indoor heat exchanger and the gas-liquid separator, the other end of the shunting branch is communicated with the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve, and a second electronic expansion valve is arranged on the shunting branch; the liquid pipe pressure sensor is arranged on the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve and used for detecting liquid pipe pressure. Part of high-pressure refrigerant in the liquid pipe is introduced into the gas-liquid separator through the shunting branch, so that the pressure of the liquid pipe is reduced, the refrigerant in the liquid pipe is prevented from being in an overpressure state in an external high-temperature environment, and the safety of the liquid pipe is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioners, and in particular to a control method and a control device for a multi-split air conditioner. Background Art

[0002] With the popularization of air conditioners, multi-split air conditioners are usually used for temperature regulation in factories, shopping malls or commercial office buildings. Multi-split air conditioners can centrally control the temperature of a larger working area, which is more convenient to use. In the related art, during the actual installation and use of multi-split air conditioners, the indoor unit installation position is often higher than the outdoor unit installation position. When the multi-split air conditioner is turned off, part of the refrigerant in multiple indoor units and long pipes flows back to the outdoor unit side, and the other part flows back and is stored in the liquid pipe. When the external ambient temperature rises, the refrigerant stored in the liquid pipe will vaporize, causing the pressure in the liquid pipe to rise rapidly, which may exceed the maximum design pressure in the liquid pipe and cause the liquid pipe to burst, seriously affecting the safety and stability of the air conditioner. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention proposes a multi-split air conditioner, in which a shunt branch is provided on the liquid pipe between the outdoor heat exchanger and the indoor heat exchanger, and the other end of the shunt branch is connected to the gas-liquid separator. Under certain liquid pipe pressure conditions, part of the refrigerant in the liquid pipe can be passed into the gas-liquid separator to avoid the refrigerant in the liquid pipe from being in an overpressure state under an external high temperature environment, thereby improving the safety of the liquid pipe and the multi-split air conditioner.

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

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

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

[0007] According to a first aspect of the present invention, a multi-split air conditioner is provided, comprising:

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

[0009] A gas-liquid separator is arranged on the refrigerant pipeline between the air intake of the compressor and the indoor heat exchanger;

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

[0011] A liquid pipe pressure sensor is provided on the refrigerant pipe between the outdoor heat exchanger and the first electronic expansion valve, and is used to detect the liquid pipe pressure;

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

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

[0014] A plate heat exchanger, the plate heat exchanger comprising 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 arranged 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 air intake port and the air exhaust port of the compressor, a solenoid valve is provided on the bypass branch, and the solenoid valve is electrically connected to the controller.

[0016] According to a second aspect of the present invention, a method for controlling a multi-split air conditioner is provided, comprising:

[0017] When a shutdown signal is received, the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve is obtained, and the real-time pressure state of the liquid pipe is determined according to the liquid pipe pressure and a predetermined state relationship; wherein the real-time pressure state includes an overpressure state and an underpressure state;

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

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

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

[0023] The first target opening is determined according to 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] Determining a relationship between the liquid pipe pressure and a predetermined pressure threshold;

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

[0027] According to an embodiment of the present invention, when a shutdown signal is received, the control method further includes:

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

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

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

[0031] an acquisition module, configured to acquire the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve when receiving a shutdown signal, and determine the real-time pressure state of the liquid pipe according to the liquid pipe pressure and a predetermined state relationship; wherein the real-time pressure state includes an overpressure state and an underpressure state;

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

[0033] A multi-split air conditioner provided in accordance with an embodiment of a fourth aspect of the present invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, steps of a control method for a multi-split air conditioner provided in accordance with an embodiment of the second aspect of the present invention are implemented.

[0034] The above one or more technical solutions in the present invention have at least one of the following technical effects:

[0035] According to an embodiment of the present invention, a multi-split air conditioner includes a compressor, an outdoor heat exchanger, a first electronic expansion valve, an indoor heat exchanger, a gas-liquid separator and a shunt branch; the compressor, the outdoor heat exchanger, the first electronic expansion valve and the indoor heat exchanger are connected to form a refrigerant circulation loop through a refrigerant pipeline, and the gas-liquid separator is arranged on the refrigerant pipeline between the air intake of the compressor and the indoor heat exchanger; one end of the shunt branch 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, and a second electronic expansion valve is arranged on the shunt branch; a liquid pipe pressure sensor is arranged on the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve, and is used to detect the liquid pipe pressure; a controller is electrically connected to the first electronic expansion valve, the second electronic expansion valve and the liquid pipe pressure sensor, and the controller is configured to adjust the opening of the second electronic expansion valve to the target opening according to the liquid pipe pressure when a shutdown signal is received. When the real-time pressure state in the liquid pipe is an overpressure state, the first target opening is determined according to the liquid pipe pressure and the first adjustment relationship, and a signal is sent to adjust the opening of the second electronic expansion valve to the first target opening; wherein the first target opening is greater than the current opening of the second electronic expansion valve. Part of the high-pressure refrigerant in the liquid pipe is passed into the gas-liquid separator through the shunt branch, which increases the storage space of the refrigerant, reduces the pressure of the refrigerant in the liquid pipe, avoids the refrigerant in the liquid pipe from being in an overpressure state under high temperature conditions, and improves the safety of the liquid pipe and the multi-split air conditioner. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

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

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

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

[0041] Reference numerals:

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

[0043] 301, acquisition module; 302, signal sending module. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the invention clearer, the technical solution in the invention will be clearly described below in conjunction with the drawings in the invention. Obviously, the described embodiments are part of the embodiments of the invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without creative work 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", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and 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 devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0046] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0047] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0048] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0049] In the related art, during the actual installation and use of multi-split air conditioners, the indoor unit installation position is often higher than the outdoor unit installation position. When the multi-split air conditioner is turned off, part of the refrigerant in the multiple indoor units and long pipes flows back to the outdoor unit side, and the other part flows back and is stored in the liquid pipe. When the external ambient temperature rises, the refrigerant stored in the liquid pipe will vaporize, causing the pressure in the liquid pipe to rise rapidly, which may exceed the maximum design pressure in the liquid pipe and cause the liquid pipe to burst, seriously affecting the safety and stability of the air conditioner.

[0050] According to the multi-split air conditioner provided by the first embodiment of the present invention, please refer to Figure 1 , including a compressor 11, an outdoor heat exchanger 12, a first electronic expansion valve, an indoor heat exchanger 14, a gas-liquid separator 15, a shunt branch 16, a liquid pipe pressure sensor 18 and a controller.

[0051] Among them, the compressor 11, the outdoor heat exchanger 12, the first electronic expansion valve and the indoor heat exchanger 14 are connected through a refrigerant pipeline to form a refrigerant circulation loop. The refrigerant circulation loop can also be provided with a four-way valve, a liquid pipe stop valve, a gas pipe stop valve and multiple sensors.

[0052] In the multi-split air conditioner provided in the embodiment of the present invention, a plurality of indoor units are arranged in parallel, and each indoor unit includes an indoor heat exchanger 14 and an indoor expansion valve, and the indoor expansion valve can be used as a first electronic expansion valve of a refrigerant circulation loop. Figure 1 Not shown, each indoor unit can be controlled independently.

[0053] A gas-liquid separator 15 is provided on the refrigerant pipeline between the air intake of the compressor 11 and the indoor heat exchanger 14, and a space for storing liquid refrigerant is provided in the gas-liquid separator 15. During normal operation, the gas-liquid separator 15 can filter the refrigerant before the air intake of the compressor 11, retain the liquid refrigerant in the gas-liquid separator 15, and pass the gaseous refrigerant into the air intake of the compressor 11, thereby avoiding liquid hammer in the compressor 11 and improving the safety of the compressor 11.

[0054] In the embodiment of the present invention, the multi-split air conditioner further includes a shunt branch 16, one end of which 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, and a second electronic expansion valve 17 is provided on the shunt branch 16. By adjusting the opening of the second electronic expansion valve 17, part of the refrigerant can flow into the gas-liquid separator 15 along the shunt branch 16. The liquid pipe pressure sensor 18 is provided on the refrigerant pipeline between the outdoor heat exchanger 12 and the first electronic expansion valve, and is used to detect the liquid pipe pressure.

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

[0056] In the multi-split air conditioner provided by the embodiment of the present invention, when the real-time pressure state in the liquid pipe is in an overpressure state, the first target opening is determined according to the liquid pipe pressure and the first adjustment relationship, and a signal is sent to adjust the opening of the second electronic expansion valve 17 to the first target opening; wherein the first target opening is greater than the current opening of the second electronic expansion valve 17. Part of the high-pressure refrigerant in the liquid pipe is passed into the gas-liquid separator 15 through the shunt branch 16, which increases the storage space of the refrigerant, reduces the pressure of the refrigerant in the liquid pipe, avoids the refrigerant in the liquid pipe from being in an overpressure state under an external high temperature environment, and improves 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 through a refrigerant pipeline, the first heat exchange outlet is connected to the first electronic expansion valve through a refrigerant pipeline, the second heat exchange inlet is connected to the first heat exchange outlet through a refrigerant pipeline, the second heat exchange outlet is connected to the inlet of the gas-liquid separator 15 through a refrigerant pipeline, and the second electronic expansion valve 17 is arranged on the refrigerant pipeline between the first heat exchange outlet and the second heat exchange inlet.

[0058] See also Figure 1In the multi-split air conditioner provided in the embodiment of the present invention, the shunt branch 16 is an enthalpy-increasing branch. When the multi-split air conditioner is operating normally, opening the second electronic expansion valve 17 can make a part of the refrigerant evaporate and absorb heat in the plate heat exchanger 19, and can make the refrigerant flowing to the indoor heat exchanger 14 in a supercooled state. This part of the evaporated refrigerant enters the compressor 11 after absorbing heat, which can improve the heat exchange efficiency of the indoor heat exchanger 14 and improve the cooling and heating power of the compressor 11. When the multi-split air conditioner is turned off, when the enthalpy-increasing branch (shunt branch 16) is opened, part of the refrigerant in the liquid pipe between the outdoor heat exchanger 12 and the indoor heat exchanger 14 can be passed into the gas-liquid separator 15, making full use of the storage space in the gas-liquid separator 15, thereby avoiding overpressure of the refrigerant in the liquid pipe under high temperature environment, and improving the safety of the liquid pipe.

[0059] When the multi-split air conditioner is shut down, the liquid pipe is depressurized through the enthalpy increase branch and the refrigerant is temporarily stored in the gas-liquid separator 15. The enthalpy increase branch and the gas-liquid separator 15 are both existing structures of the multi-split air conditioner. Liquid pipe depressurization and refrigerant collection can be achieved without setting up an additional refrigerant collection device, thereby reducing the use cost of the multi-split air conditioner.

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

[0061] See also Figure 1 A bypass branch 20 is provided between the air inlet and the air outlet of the compressor 11, and a solenoid valve 21 is provided on the bypass branch 20. When the multi-split air conditioner is turned off, if opening the second electronic expansion valve 17 still cannot satisfy the pressure relief of the liquid pipe, the solenoid valve 21 may be opened. Figure 1 It can be seen that after the solenoid valve 21 is opened, the refrigerant pipeline between the outdoor heat exchanger 12 and the exhaust port of the compressor 11, the bypass branch 20, and the refrigerant pipeline between the bypass branch 20 and the gas-liquid separator 15 can all become potential refrigerant storage locations, thereby further reducing the refrigerant pressure in the liquid pipe and improving the safety of the liquid pipe. The controller is electrically connected to the solenoid valve 21, and the controller is configured to open the solenoid valve 21 based on the liquid pipe pressure meeting a predetermined pressure threshold, and the liquid pipe pressure required when the solenoid valve 21 is opened is greater than the liquid pipe pressure when the second solenoid valve 21 adjusts the opening.

[0062] In some embodiments, the refrigerant circulation loop further includes a liquid pipe stop valve and a gas pipe stop valve, and the liquid pipe stop valve and the gas pipe stop valve are electrically connected to the controller. When the multi-split air conditioner is turned off, the liquid pipe stop valve and the gas pipe stop valve can be controlled to be in a closed state, so that part of the refrigerant is sealed in the indoor heat exchanger 14, so as to prevent all the refrigerant from flowing to the liquid pipe and the outdoor heat exchanger 12, thereby reducing the liquid pipe pressure.

[0063] According to the control method of the multi-split air conditioner provided by the second embodiment of the present invention, please refer to Figure 2 ,include:

[0064] S200. When a shutdown signal is received, the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve is obtained, and the real-time pressure state of the liquid pipe is determined according to the relationship between the liquid pipe pressure and a predetermined state; wherein the real-time pressure state includes an overpressure state and an underpressure state.

[0065] It is understandable that in response to the shutdown signal, the multi-split air conditioner is not powered off immediately, but the components are adjusted to the initial state or the state ready for the next start-up through the electric energy stored in the storage component or the mains electric energy. The liquid pipe pressure is obtained through the liquid pipe pressure sensor, and the real-time pressure state of the liquid pipe is determined according to the liquid pipe pressure and the predetermined state relationship, wherein the predetermined state relationship includes the pressure threshold, the corresponding relationship between the pressure area and the pressure state, etc. For example, if the liquid pipe pressure is greater than or equal to the pressure threshold, the real-time pressure state is an overpressure state.

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

[0067] It is understandable that when the real-time pressure state is an overpressure state, the liquid pipe is in an unsafe state, the external environment temperature is high, and cracks may appear in different pipe connectors due to different thermal expansion and contraction coefficients. The liquid pipe may also burst under overpressure, which may lead to safety accidents. In an embodiment of the present invention, when the real-time pressure state is an overpressure state, the first target opening is determined according to the liquid pipe pressure and the first adjustment relationship, and 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, so that part of the refrigerant in the liquid pipe can gradually flow into the gas-liquid separator. At the same time, if the liquid pipe pressure is large, the opening adjustment range of the second electronic expansion valve is also large, so as to achieve rapid adjustment of the liquid pipe pressure and reduce the refrigerant pressure in the liquid pipe as soon as possible, thereby ensuring the immediacy of the liquid pipe pressure adjustment.

[0068] In some embodiments, the step of determining the first target opening degree according to the liquid pipe pressure and the first adjustment relationship specifically includes:

[0069] An adjustment coefficient and an adjustment function corresponding to the first adjustment relationship are obtained, and a difference between the liquid pipe pressure and a preset liquid pipe pressure is determined.

[0070] The first target opening is determined according to the difference, the adjustment coefficient and the adjustment function.

[0071] It can be understood that the first target opening determined according to the liquid pipe pressure and the first regulation relationship has a positive correlation. For example, if the liquid pipe pressure is larger, the opening adjustment range of the second electronic expansion valve is also larger, so as to achieve rapid regulation of the liquid pipe pressure and reduce the refrigerant pressure in the liquid pipe as quickly as possible, thereby ensuring the immediacy of the liquid pipe pressure regulation.

[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 regulation relationship meets 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 regulation 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 pipe according to the liquid pipe pressure and a predetermined state relationship further includes:

[0075] S240. When the real-time pressure state is a low pressure state, a second target opening is determined according to the liquid pipe pressure and the second adjustment relationship, and a signal is sent to adjust the opening of the second electronic expansion valve to the second target opening; wherein the second target opening is smaller than the current opening of the second electronic expansion valve.

[0076] It is understandable that when the real-time pressure state is a low-pressure state, the opening of the second expansion valve can be adjusted to the second target opening, at which time the liquid pipe pressure can be kept stable to prepare for the next startup.

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

[0078] The relationship between the liquid pipe pressure and a predetermined pressure threshold is determined.

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

[0080] See also Figure 1 A bypass branch is provided between the air intake and the exhaust port of the compressor, and a solenoid valve is provided on the bypass branch. When the multi-split air conditioner is turned off, if opening the second electronic expansion valve still cannot relieve the pressure in the liquid pipe, the solenoid valve can be opened. Figure 1It can be seen that after the solenoid valve is opened, the refrigerant pipeline between the outdoor heat exchanger and the compressor exhaust port, the bypass branch, and the refrigerant pipeline between the bypass branch and the gas-liquid separator can all become potential refrigerant storage locations, thereby further reducing the refrigerant pressure in the liquid pipe and improving the safety of the liquid pipe. The controller is electrically connected to the solenoid valve, and the controller is configured to open the solenoid valve based on the liquid pipe pressure meeting a predetermined pressure threshold, and the liquid pipe pressure required when the solenoid valve is opened is greater than the liquid pipe pressure when the second solenoid valve adjusts the opening.

[0081] In some embodiments, when a shutdown signal is received, the control method of the multi-split air conditioner further includes:

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

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

[0084] It is understandable that when the power supply system suddenly loses power, the multi-split air conditioner will also generate a shutdown signal and use the power of the storage module to complete the shutdown action. If a shutdown signal is received, the power-on status of the multi-split air conditioner can be detected first. The power-on status here 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, the actions of steps S200, S220 and S240 are completed; if the multi-split air conditioner is in a power-off state, the action of step S250 is completed to prepare for the subsequent startup.

[0085] According to the third aspect of the present invention, the control device of the multi-split air conditioner is provided. Figure 3 ,include:

[0086] The acquisition module 301 is used to obtain 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 determine 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.

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

[0088] It should be noted that the above steps S200 to S220, as well as other steps, are only for the convenience of expression, and do not constitute a time sequence limitation for each step in the control method of the multi-split air conditioner. In addition, some contents are described in detail in the control method of the multi-split air conditioner provided in the second aspect embodiment, and the contents in all the control methods of the multi-split air conditioner are also applicable to the control device of the multi-split air conditioner provided in the third aspect embodiment, and in order to avoid repetition, the control device of the multi-split air conditioner provided in the third aspect embodiment is not described in detail. Similarly, the contents in the above two aspects of the embodiments can be used to explain the contents of all the subsequent aspects of the embodiments, so the repeated contents will not be repeated in the subsequent embodiments. The technical effect of the control device of the multi-split air conditioner provided in the embodiment of the present invention corresponds to the technical effect of the above-mentioned control method of the multi-split air conditioner, and will not be repeated here.

[0089] A multi-split air conditioner provided in accordance with an embodiment of a fourth aspect of the present invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, steps of a control method for a multi-split air conditioner provided in accordance with an embodiment of the second aspect of the present invention are implemented.

[0090] Figure 4 The physical structure diagram of an electronic device of a multi-split air conditioner is illustrated, and the electronic device may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 complete mutual communication through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the control method of the multi-split air conditioner, and the method includes: when receiving a shutdown signal, obtaining 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 according to 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 according to the liquid pipe pressure and a first adjustment relationship, and sending a signal to adjust the opening of the second electronic expansion valve to the first target opening; wherein the first target opening is greater than the current opening of the second electronic expansion valve.

[0091] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0092] The device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without paying creative labor.

[0093] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A multi-split air conditioner, characterized in that: include: A refrigerant circulation loop formed by at least a compressor, an outdoor heat exchanger, a first electronic expansion valve and an indoor heat exchanger connected by a refrigerant pipeline; A gas-liquid separator is arranged on the refrigerant pipeline between the air intake of the compressor and the indoor heat exchanger; A shunt branch, one end of which is connected to the inlet of the gas-liquid separator, and the other end of which is connected to the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve, and a second electronic expansion valve is provided on the shunt branch; A liquid pipe pressure sensor is provided on the refrigerant pipe between the outdoor heat exchanger and the first electronic expansion valve, and is used to detect the liquid pipe pressure; The controller is electrically connected to the first electronic expansion valve, the second electronic expansion valve and the liquid pipe pressure sensor. The controller is configured to adjust the opening of the second electronic expansion valve to a target opening according to the liquid pipe pressure when receiving a shutdown signal.

2. The multi-split air conditioner according to claim 1, characterized in that: Also includes: A plate heat exchanger, the plate heat exchanger comprising 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 arranged on the refrigerant pipeline between the first heat exchange outlet and the second heat exchange inlet.

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

4. A control method for a multi-split air conditioner according to any one of claims 1 to 3, characterized in that: include: When a shutdown signal is received, the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve is obtained, and the real-time pressure state of the liquid pipe is determined according to the liquid pipe pressure and a predetermined state relationship; wherein the real-time pressure state includes an overpressure state and an underpressure state; When the real-time pressure state is the overpressure state, a first target opening is determined according to the liquid pipe pressure and a first regulation relationship, and a signal is sent to adjust the opening of the second electronic expansion valve to the first target opening; wherein the first target opening is greater than the current opening of the second electronic expansion valve.

5. The control method of a multi-split air conditioner according to claim 4, characterized in that: The step of determining the real-time pressure state of the liquid pipe according to 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 is determined according to the liquid pipe pressure and the second regulation relationship, and a signal is sent to adjust the opening of the second electronic expansion valve to the second target opening; wherein the second target opening is smaller than the current opening of the second electronic expansion valve.

6. The control method of a multi-split air conditioner according to claim 4, characterized in that: The step of determining the first target opening degree according to the liquid pipe pressure and the first adjustment relationship specifically includes: Acquire an adjustment coefficient and an adjustment function corresponding to the first adjustment relationship, and determine a difference between the liquid pipe pressure and a preset liquid pipe pressure; The first target opening is determined according to the difference, the adjustment coefficient and the adjustment function.

7. The control method of a multi-split air conditioner according to claim 4, characterized in that: When the real-time pressure state is the overpressure state, the control method further includes: Determining a relationship between the liquid pipe pressure and a predetermined pressure threshold; When the liquid pipe pressure is greater than or equal to the predetermined pressure threshold, a signal is sent to control the solenoid valve to open.

8. The control method of a multi-split air conditioner according to claim 4, characterized in that: When a shutdown signal is received, the control method further includes: Obtaining the power-on status of the multi-split air conditioner; When the multi-split air conditioner is in a power-off state, a signal is sent to adjust the opening degree of the second electronic expansion valve to a normally open opening degree.

9. A control device for a multi-split air conditioner, characterized in that: include: an acquisition module, configured to acquire the liquid pipe pressure of the refrigerant pipeline between the outdoor heat exchanger and the first electronic expansion valve when receiving a shutdown signal, and determine the real-time pressure state of the liquid pipe according to the liquid pipe pressure and a predetermined state relationship; wherein the real-time pressure state includes an overpressure state and an underpressure state; A signal sending module is used to determine a first target opening according to the liquid pipe pressure and a first adjustment relationship when the real-time pressure state is the overpressure state, and send a signal to adjust the opening of the second electronic expansion valve to the first target opening; wherein the first target opening is greater than the current opening of the second electronic expansion valve.

10. 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, the steps of the control method of the multi-split air conditioner as described in any one of claims 4 to 8 are implemented.

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