Safety device and multi-split system, control method and controller thereof

Abstract

The invention discloses a safety device and a multi-split air conditioner system, a control method and a controller thereof.The safety device comprises a first pipe opening, a second pipe opening, a third pipe opening, a fourth pipe opening and a switching assembly, the first pipe opening communicates with one refrigerant pipeline opening of an outdoor heat exchanger, and the third pipe opening communicates with the other refrigerant pipeline opening of the outdoor heat exchanger; the second pipe opening communicates with one refrigerant pipeline opening of the indoor heat exchanger, the fourth pipe opening communicates with the other refrigerant pipeline opening of the indoor heat exchanger, and the switching assembly is used for being controlled to be switched between the first state and the second state. In the first state, the first pipe opening is communicated with the second pipe opening, and the third pipe opening is communicated with the fourth pipe opening; in the second state, the first pipe opening is not communicated with the second pipe opening, and the third pipe opening is not communicated with the fourth pipe opening. According to the safety device and the multi-split air conditioning system, the control method and the controller thereof, the indoor unit leaking the refrigerant can not affect normal operation of other indoor units.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioning systems, and in particular to a safety device and a multi-connected system, a control method, and a controller thereof. Background Art

[0002] The outdoor unit and indoor unit of the air-conditioning system are generally connected by a refrigerant pipe. The compressor of the air-conditioning system drives the refrigerant to circulate in the refrigerant pipe and causes the refrigerant to exchange heat at the outdoor heat exchanger and the indoor heat exchanger to achieve cooling and heating of the air-conditioning system.

[0003] The multi-split system can drive multiple indoor units through one outdoor unit. The refrigerant filling volume in the refrigerant pipeline is large, and the refrigerant pipeline of the multi-split system is connected to the outdoor unit and multiple indoor units. Once the refrigerant leaks at the indoor heat exchanger of an indoor unit, the refrigerant in the multi-split system will leak into the same room, and the indoor units in other rooms will not work properly. Summary of the invention

[0004] The embodiments of the present application provide a safety device and a multi-split system, a control method, and a controller thereof, which can ensure that an indoor unit leaking refrigerant does not affect the normal operation of other indoor units.

[0005] In a first aspect, an embodiment of the present application provides a safety device, comprising a first pipe opening, a second pipe opening, a third pipe opening, a fourth pipe opening and a switching component, wherein the first pipe opening is connected to a refrigerant pipe opening of an outdoor heat exchanger, the third pipe opening is connected to another refrigerant pipe opening of the outdoor heat exchanger, the second pipe opening is connected to a refrigerant pipe opening of an indoor heat exchanger, the fourth pipe opening is connected to another refrigerant pipe opening of the indoor heat exchanger, and the switching component is used to be controlled to switch between a first state and a second state;

[0006] Wherein, the first state is: the first pipe opening is connected to the second pipe opening, and the third pipe opening is connected to the fourth pipe opening; the second state is: the first pipe opening is not connected to the second pipe opening, and the third pipe opening is not connected to the fourth pipe opening.

[0007] In some embodiments, the switching assembly includes a first pipe and a second pipe. In the first state, the first pipe connects the first pipe opening and the second pipe opening, and the second pipe connects the third pipe opening and the fourth pipe opening; in the second state, the first pipe connects the first pipe opening and the third pipe opening, and the second pipe connects the second pipe opening and the fourth pipe opening.

[0008] In some embodiments, the switching component switches to the first state when powered on, and switches to the second state when powered off.

[0009] In some embodiments, the switching assembly is a valve core assembly, and the valve core assembly opens the first pipe and the second pipe. The valve core assembly rotates when power is on so that the first pipe connects the first pipe opening and the second pipe opening. The valve core assembly rotates when power is off so that the second pipe connects the second pipe opening and the fourth pipe opening.

[0010] In a second aspect, an embodiment of the present application provides a multi-split system, comprising an outdoor unit, multiple indoor units and multiple safety devices as described in the embodiment of the first aspect, wherein the safety device is arranged between the outdoor heat exchanger of the outdoor unit and the indoor heat exchanger of the indoor unit.

[0011] In some embodiments, the multi-split system also includes a refrigerant leakage detection device corresponding to the indoor unit; the multi-split system is used to determine the target indoor unit corresponding to the refrigerant detection device and control the safety device corresponding to the target indoor unit to switch to the second state when the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration.

[0012] In a third aspect, an embodiment of the present application provides a control method for a multi-split system, which is applied to the multi-split system of the second aspect, wherein the multi-split system further includes a refrigerant leakage detection device corresponding to the indoor unit; the control method includes:

[0013] When the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration, determining a target indoor unit corresponding to the refrigerant detection device;

[0014] The safety device corresponding to the target indoor unit is controlled to switch to the second state.

[0015] In some embodiments, the control method further includes:

[0016] After the multi-split system is started up, determining a target indoor unit operating in a cooling mode or a heating mode;

[0017] Controlling the safety device corresponding to the target indoor unit to switch to a first state;

[0018] When the target indoor unit exits the cooling mode or the heating mode, the safety device corresponding to the target indoor unit is controlled to switch to the second state.

[0019] In some embodiments, when the target indoor unit exits the cooling mode or the heating mode, controlling the safety device corresponding to the target indoor unit to switch to the second state includes:

[0020] When the target indoor unit changes from the heating mode to the shutdown state, controlling the safety device corresponding to the target indoor unit to switch to the second state;

[0021] When the target indoor unit changes from cooling mode to shutdown mode, the expansion valve corresponding to the target indoor unit is controlled to close, and after the expansion valve is closed for a first preset time, the safety device corresponding to the target indoor unit is controlled to switch to the second state.

[0022] In some embodiments, the control method further includes:

[0023] When all the indoor units are in standby mode, the compressor of the multi-split system is controlled to stop;

[0024] All the indoor units are kept in a standby state within a second preset time after the compressor is stopped, the compressor is started at a preset operating frequency, all the indoor units are controlled to operate in a cooling mode, the expansion valves corresponding to all the indoor units are controlled to be closed, and all the safety devices are controlled to switch to the first state;

[0025] After the compressor is started at the preset operating frequency for a third preset time, all the safety devices are controlled to switch to the second state, and the compressor is controlled to stop.

[0026] In some embodiments, the control method further includes:

[0027] When the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration, the target indoor unit is controlled to issue a refrigerant leakage prompt message.

[0028] In a fourth aspect, an embodiment of the present application provides a controller comprising at least one processor and a memory for communicating with the at least one processor; the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method as described in the embodiment of the third aspect.

[0029] The safety device and its multi-split system, control method, and controller of the embodiments of the present application have at least the following beneficial effects: the safety device controls the connection and disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger by switching between a first state and a second state; when it is detected that the refrigerant concentration in the room of a certain indoor unit exceeds a certain value, the multi-split system can control the safety device to switch to the second state, disconnecting the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger of the indoor unit, thereby preventing the refrigerant from leaking into the room and ensuring that other indoor units in the multi-split system can operate normally without being affected; on the other hand, the multi-split system can also cooperate with the startup control of the indoor unit through the first state and the second state of the safety device to improve the problems caused by the residual refrigerant in the indoor unit.

[0030] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a system structure diagram of a multi-connection system provided in an embodiment of the present application;

[0032] Figure 2 is a schematic diagram of the structure of the safety device provided by an embodiment of the present application in a first state;

[0033] Figure 3 is a schematic diagram of the structure of the safety device provided by an embodiment of the present application in the second state;

[0034] Figure 4 is a flow chart of a control method for a multi-connected system provided in an embodiment of the present application;

[0035] Figure 5 is a flow chart of a control method of a multi-link system provided by another embodiment of the present application;

[0036] Figure 6 yes Figure 5 Flow chart of step S500 in FIG.

[0037] Figure 7 It is a flow chart of a control method of a multi-link system provided by another embodiment of the present application.

[0038] Reference numerals:

[0039] Safety device 100, first pipe opening 110, second pipe opening 120, third pipe opening 130, fourth pipe opening 140, first pipeline 151, second pipeline 152;

[0040] Outdoor unit 200, expansion valve 210, capillary tube 220, outdoor heat exchanger 230, four-way valve 240, compressor 250, gas-liquid separator 260;

[0041] Indoor unit 300. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. In addition, the characteristics, operations or features described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be replaced or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a necessary sequence, unless otherwise specified that a certain sequence must be followed.

[0043] In the description of this application, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, and "above", "below", "within", etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0044] The serial numbers of the components in this document, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings).

[0045] The outdoor unit 200 and the indoor unit 300 of the air-conditioning system are generally connected by a refrigerant pipe. The compressor 250 of the air-conditioning system drives the refrigerant to circulate in the refrigerant pipe and causes the refrigerant to exchange heat at the outdoor heat exchanger 230 and the indoor heat exchanger to achieve cooling and heating of the air-conditioning system.

[0046] The multi-split system can drive multiple indoor units 300 to work through one outdoor unit 200. The refrigerant filling amount in the refrigerant pipeline is large, and the refrigerant pipeline of the multi-split system is connected to the outdoor unit 200 and multiple indoor units 300. Once the refrigerant leaks at the indoor heat exchanger of an indoor unit 300, the refrigerant in the multi-split system will leak into the same room, and eventually shut down for protection, and the indoor units 300 in other rooms will also not work normally.

[0047] Based on this, an embodiment of the present application provides a safety device 100 and its multi-split system, control method, and controller, which can control the disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 of the indoor unit 300 where the refrigerant leakage occurs, thereby preventing the refrigerant in the multi-split system from leaking into the room where the refrigerant leakage occurs, and ensuring that the other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 leaking the refrigerant does not affect the normal operation of other indoor units 300, thereby improving the system operation reliability.

[0048] In order to better illustrate the advantages of the safety device 100 according to the embodiment of the present application, first, the multi-link system according to the embodiment of the present application is described.

[0049] Reference Figure 1 As shown, an embodiment of the present application provides a multi-split system, comprising an outdoor unit 200, multiple indoor units 300 and multiple safety devices 100 as described in the above embodiments, wherein the safety device 100 is arranged between the outdoor heat exchanger 230 of the outdoor unit 200 and the indoor heat exchanger of the indoor unit 300.

[0050] The outdoor unit 200 includes, but is not limited to, an expansion valve 210 , a capillary tube 220 , an outdoor heat exchanger 230 , a four-way valve 240 , a compressor 250 , and a gas-liquid separator 260 ;

[0051] The expansion valve 210 has a first valve port and a second valve port, and the first valve port is connected to the first pipe port 110 of the safety device 100;

[0052] The capillary tube 220 has a first port and a second port, and the first port is connected to the second valve port;

[0053] The outdoor heat exchanger 230 has a first refrigerant pipeline port and a second refrigerant pipeline port, and the first refrigerant pipeline port is connected to the second port;

[0054] The four-way valve 240 has a first four-way valve port 240, a second four-way valve port 240, a third four-way valve port 240 and a fourth four-way valve port 240, the first four-way valve port 240 is connected to the second refrigerant pipeline port, and the fourth four-way valve port 240 is connected to the third pipe port 130 of the safety device 100;

[0055] The compressor 250 has a first compression port and a second compression port, and the first compression port is connected to the third four-way valve 240 port;

[0056] The gas-liquid separator 260 has a first separation port and a second separation port. The first separation port is communicated with the second compression port, and the second separation port is communicated with the second four-way valve 240 port.

[0057] The expansion valve 210 plays a role in throttling and reducing pressure. During the operation of the air conditioner, by adjusting the expansion valve 210, the occurrence of excessively high exhaust temperature of the compressor 250 can be suppressed. When the exhaust temperature is too high, the expansion valve 210 will increase the opening to reduce the exhaust temperature. During the operation of the air conditioner, by adjusting the opening of the expansion valve 210, the situation of excessively low pressure can be suppressed. Controlling the expansion valve 210 to increase the opening to increase the low pressure can prevent the occurrence of negative pressure.

[0058] The capillary tube 220 plays a role of reducing pressure and throttling, which can prevent the normal temperature and high pressure liquid refrigerant that has been liquefied in the condenser from directly entering the outdoor heat exchanger 230, thereby reducing the pressure in the outdoor heat exchanger 230 and facilitating the evaporation of the refrigerant.

[0059] It should be noted that the structures, functions and working principles of the outdoor heat exchanger 230, the compressor 250 and the gas-liquid separator 260 are all prior art known to those skilled in the art, and will not be described in detail here. In addition, the overall working principle of the outdoor unit 200 is also prior art known to those skilled in the art, and will not be described in detail here.

[0060] In some embodiments, the multi-split system further includes a refrigerant leakage detection device corresponding to the indoor unit 300; the multi-split system is used to determine the target indoor unit 300 corresponding to the refrigerant detection device and control the safety device 100 corresponding to the target indoor unit 300 to switch to the second state when the refrigerant detection device detects that the refrigerant concentration exceeds the preset concentration. When the refrigerant detection device detects that the refrigerant concentration exceeds the preset concentration, the target indoor unit 300 will also be controlled to issue a refrigerant leakage prompt message, but only the indoor unit 300 that detects that the refrigerant concentration exceeds the preset concentration will display the refrigerant leakage prompt message. After the leakage is restored (such as replacing the indoor unit 300 to eliminate the alarm prompt), the indoor unit 300 resumes normal operation.

[0061] It should be noted that the specific structure and working principle of the refrigerant leakage detection device are prior arts known to those skilled in the art and will not be described in detail here.

[0062] The safety device 100, the control method, and the controller are described below in conjunction with the accompanying drawings:

[0063] Reference Figure 2 and Figure 3As shown, a safety device 100 provided in an embodiment of the present application includes a first pipe opening 110, a second pipe opening 120, a third pipe opening 130, a fourth pipe opening 140 and a switching component, wherein the first pipe opening 110 is connected to a refrigerant pipe opening of an outdoor heat exchanger 230, the third pipe opening 130 is connected to another refrigerant pipe opening of the outdoor heat exchanger 230, the second pipe opening 120 is connected to a refrigerant pipe opening of an indoor heat exchanger, and the fourth pipe opening 140 is connected to another refrigerant pipe opening of the indoor heat exchanger, and the switching component is used to be controlled to switch between a first state and a second state;

[0064] The first state is that the first pipe opening 110 is connected to the second pipe opening 120, and the third pipe opening 130 is connected to the fourth pipe opening 140; the second state is that the first pipe opening 110 is not connected to the second pipe opening 120, and the third pipe opening 130 is not connected to the fourth pipe opening 140.

[0065] The multi-split system of the embodiment of the present application includes an outdoor unit 200, a plurality of indoor units 300 and a plurality of safety devices 100, and a safety device 100 is disposed between the outdoor heat exchanger 230 of the outdoor unit 200 and the indoor heat exchanger of each indoor unit 300.

[0066] When the multi-link system of the embodiment of the present application is in normal operation, the safety device 100 of the embodiment of the present application has the following advantages:

[0067] (1) In a conventional multi-split system, when the outdoor unit 200 is cooling, the expansion valve 210 corresponding to the indoor unit 300 that has no energy demand is closed, but the liquid pipe side is still connected to the compressor 250. The indoor heat exchanger is in a state of being continuously evacuated by the compressor 250. The pressure pulsation of the compressor 250 will be transmitted to the indoor heat exchanger, which may cause the indoor unit 300 pipeline and structural parts to vibrate and produce abnormal noise.

[0068] For the multi-split system of the embodiment of the present application, when the system is turned on and running, the safety device 100 corresponding to the indoor unit 300 with energy demand will receive a power-on command. After receiving the power-on command, the switching component is controlled to switch to the first state, so that the first pipe opening 110 and the second pipe opening 120 are connected, and the third pipe opening 130 and the fourth pipe opening 140 are connected, so that the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 can be controlled to be connected. The refrigerant can circulate between the indoor unit 300 and the outdoor unit 200 through the safety device 100, realizing normal cooling and heating, and ensuring the normal operation of the entire multi-split system. The expansion valve 210 corresponding to other indoor units 300 that are not needed (in standby, temperature shutdown or air supply state) is closed, the corresponding safety device 100 is in a power-off state, the switching component is in the second state, the first pipe opening 110 and the second pipe opening 120 are not connected, the third pipe opening 130 and the fourth pipe opening 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, and the refrigerant cannot pass through. The air pipe side and the liquid pipe side of the indoor unit 300 that is not needed are not connected to the outdoor unit 200, which can effectively block the pipeline vibration and abnormal sound transmission of the indoor unit 300, thereby improving the noise problem of the indoor unit 300.

[0069] (2) In a traditional multi-split system, when heating is in operation, if an indoor unit 300 reaches a certain temperature and stops, since the expansion valve 210 is not completely closed (if it is completely closed, the refrigerant will condense and accumulate at the indoor unit 300, resulting in less and less refrigerant circulating in the system, thus affecting reliability), a small amount of high-temperature refrigerant passes through the standby indoor heat exchanger, which may cause the room to overheat.

[0070] For the multi-split system of the embodiment of the present application, during heating operation, if an indoor unit 300 reaches the temperature and shuts down, the corresponding safety device 100 will lose power, the switching component is in the second state, the first pipe opening 110 and the second pipe opening 120 are not connected, the third pipe opening 130 and the fourth pipe opening 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, and the refrigerant cannot pass through. The gas pipe side and the liquid pipe side of the indoor unit 300 that shuts down due to reaching the temperature are not connected with the outdoor unit 200, and the refrigerant cannot enter the indoor unit 300. The system circulating refrigerant will not be reduced, and the problem of overheating of the room will not occur, thereby improving the reliability and comfort of the system heating operation.

[0071] When a refrigerant leak occurs in the indoor unit 300 of the multi-split system of the present application, the safety device 100 of the present application has the following advantages:

[0072] The refrigerant pipeline of the traditional multi-split system connects the outdoor unit 200 and multiple indoor units 300. Once a refrigerant leak occurs at the indoor heat exchanger of an indoor unit 300, all the refrigerants in the multi-split system will leak into the same room, eventually shutting down for protection, and the indoor units 300 in other rooms will not be able to work normally.

[0073] For the multi-split system of the embodiment of the present application, when the outdoor unit 200 is powered off or in shutdown mode, the safety device 100 is not electrically driven, and the default is the self-locking mode, the switching component is in the second state, the first pipe opening 110 and the second pipe opening 120 are not connected, the third pipe opening 130 and the fourth pipe opening 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, the refrigerant cannot pass, the indoor unit 300 is not connected to the outdoor unit 200, most of the refrigerant is stored in the outdoor unit 200, and the indoor unit 300 can store very little refrigerant, which will not cause harm if it leaks into the room, so the outdoor unit 200 does not need to act. After the leakage is restored (such as replacing the indoor unit 300), the machine will not be affected when it is restarted and can operate normally without refilling the refrigerant, which greatly improves the maintainability of the system.

[0074] In the operation mode of the outdoor unit 200, if the refrigerant leakage detection device corresponding to a room detects a refrigerant leakage, the controller sends a power-off command to the safety device 100 of the corresponding indoor unit 300, the safety device 100 is self-locked when it is powered off, the switching component is in the second state, the first pipe opening 110 and the second pipe opening 120 are not connected, the third pipe opening 130 and the fourth pipe opening 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, the refrigerant cannot pass, the indoor unit 300 is not connected with the outdoor unit 200, the outdoor unit 200 runs without stopping, and the operation of the indoor units 300 in other rooms is not affected. After the leakage is restored, when the system is powered on again, the system resumes normal operation.

[0075] In addition, the multi-split system of the embodiment of the present application is also provided with a self-recovery control of the refrigerant of the relevant machine, which specifically includes but is not limited to the following steps:

[0076] Step S300, after the multi-split system is started, determining the target indoor unit 300 operating in the cooling mode or the heating mode;

[0077] Step S400, controlling the safety device 100 corresponding to the target indoor unit 300 to switch to the first state;

[0078] Step S510, when the target indoor unit 300 changes from the heating mode to the shutdown state, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state;

[0079] Step S520, when the target indoor unit 300 changes from the cooling mode to the shutdown state, the expansion valve 210 corresponding to the target indoor unit 300 is controlled to close, and after the expansion valve 210 is closed for a first preset time, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state.

[0080] After the multi-split system is started and operated, the target indoor unit 300 operating in cooling mode or heating mode operates normally, and the corresponding safety device 100 switches to the first state, the first pipe opening 110 and the second pipe opening 120 are connected, and the third pipe opening 130 and the fourth pipe opening 140 are connected, thereby controlling the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 to be connected. The refrigerant can circulate between the indoor unit 300 and the outdoor unit 200 through the safety device 100 to achieve normal cooling and heating.

[0081] When the target indoor unit 300 is switched from the heating mode to the shutdown state, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, and the corresponding expansion valve 210 is synchronously moved to the standby opening, which can block the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230. When the target indoor unit 300 is switched from the cooling mode to the shutdown state, the expansion valve 210 corresponding to the target indoor unit 300 is controlled to close, and after the expansion valve 210 is closed for a first preset time, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, thereby blocking the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230. Through steps S510 and S520, the refrigerant of the indoor unit 300 can be recovered to the circulation system to the greatest extent.

[0082] It should be noted that the first preset time length can be 30 seconds, or can be set to other values ​​according to actual conditions. The specific value of the first preset time length mainly depends on the actual refrigerant recovery rate and cannot be regarded as a limitation of this application.

[0083] In addition, the working principles of the cooling mode and the heating mode of the multi-split system are all existing technologies known to technical personnel in this field. When the target indoor unit 300 is switched from the cooling mode to the shutdown state, it is necessary to control the safety device 100 corresponding to the target indoor unit 300 to switch to the second state after the expansion valve 210 is closed for a first preset time. The reason can be inferred based on the working principles of the cooling mode and the heating mode of the multi-split system, and will not be repeated here.

[0084] In some embodiments, the shutdown refrigerant self-recovery control further includes but is not limited to the following steps:

[0085] Step S600, when all indoor units 300 are in standby mode, the compressor 250 of the multi-split system is controlled to stop;

[0086] Step S700, after the compressor 250 stops, all the indoor units 300 remain in a standby state within a second preset time period, the compressor 250 is started at a preset operating frequency, all the indoor units 300 are controlled to operate in a cooling mode, the expansion valves 210 corresponding to all the indoor units 300 are controlled to be closed, and all the safety devices 100 are controlled to switch to the first state;

[0087] Step S800, after starting the compressor 250 at a preset operating frequency for a third preset time, all safety devices 100 are controlled to switch to the second state, and the compressor 250 is controlled to stop.

[0088] If all the indoor units 300 are in the standby state, it means that all the indoor units 300 have no energy demand, and the compressor 250 of the multi-split system is controlled to shut down. If all the indoor units 300 remain in the standby state within the second preset time after the compressor 250 shuts down, it means that all the indoor units 300 may not have energy demand in the future, but the refrigerant may still remain in the pipes of the system, resulting in a waste of refrigerant.

[0089] At this time, the compressor 250 is started at a preset operating frequency, all indoor units 300 are controlled to operate in the cooling mode, the expansion valves 210 corresponding to all indoor units 300 are controlled to be closed, and all safety devices 100 are controlled to switch to the first state, so that the first pipe port 110 and the second pipe port 120 are connected, and the third pipe port 130 and the fourth pipe port 140 are connected. At this time, the refrigerant flow direction of the multi-split system is as follows for the side close to the indoor unit 300: from the expansion valve 210 to the first pipe port 110, the second pipe port 120, and the indoor unit 300; from the indoor unit 300 to the fourth pipe port 140, the third pipe port 130, and then back to the outdoor unit 200. At this time, the indoor fan is not turned on. Since the expansion valve 210 is closed and the refrigerant flow direction is single due to the cooling mode, the refrigerant in the system can be recovered to the outdoor unit 200 to the greatest extent, thereby improving the maintainability of the system.

[0090] After the compressor 250 starts for the third preset time, it indicates that the refrigerant has been recovered to the outdoor unit 200 to the maximum extent. At this time, all safety devices 100 are controlled to switch to the second state, the compressor 250 is controlled to stop, the first pipe port 110 and the second pipe port 120 are not connected, the third pipe port 130 and the fourth pipe port 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, the refrigerant cannot pass through, and the indoor unit 300 is not connected to the outdoor unit 200, so as to avoid refrigerant leakage.

[0091] It should be noted that the second preset time represents the judgment standard that all indoor units 300 may not be needed in the future, and can be set to 30 minutes, or other values ​​according to actual conditions, and cannot be regarded as a limitation of the present application. In addition, the third preset time represents the judgment standard that the refrigerant has been recovered to the outdoor unit 200 to the greatest extent, and can be set to 1 minute, or other values ​​according to actual conditions, and cannot be regarded as a limitation of the present application.

[0092] In some embodiments, reference Figure 2 and Figure 3As shown, the switching component includes a first pipe 151 and a second pipe 152. In a first state, the first pipe 151 connects the first pipe port 110 and the second pipe port 120, and the second pipe 152 connects the third pipe port 130 and the fourth pipe port 140; in a second state, the first pipe 151 connects the first pipe port 110 and the third pipe port 130, and the second pipe 152 connects the second pipe port 120 and the fourth pipe port 140.

[0093] The safety device 100 has a first pipe opening 110, a second pipe opening 120, a third pipe opening 130 and a fourth pipe opening 140. The first pipe opening 110 is connected to a refrigerant pipe opening of the outdoor heat exchanger 230, the third pipe opening 130 is connected to another refrigerant pipe opening of the outdoor heat exchanger 230, the second pipe opening 120 is connected to a refrigerant pipe opening of the indoor heat exchanger, and the fourth pipe opening 140 is connected to another refrigerant pipe opening of the indoor heat exchanger.

[0094] When the first pipe opening 110 and the second pipe opening 120 are connected, and the third pipe opening 130 and the fourth pipe opening 140 are connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is connected, and the refrigerant can circulate between the indoor unit 300 and the outdoor unit 200 through the safety device 100, achieving normal cooling and heating, and ensuring the normal operation of the entire multi-split system.

[0095] When the first pipe opening 110 and the third pipe opening 130 are connected, and the second pipe opening 120 and the fourth pipe opening 140 are connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, and the refrigerant entering the first pipe opening 110 from the outdoor unit 200 will flow into the outdoor unit 200 from the third pipe opening 130, which can not only effectively block the pipeline vibration and abnormal sound transmission of the indoor unit 300 and improve the noise problem of the indoor unit 300, but also avoid the problem of overheating of the room, improve the reliability and comfort of the system heating operation, and avoid the refrigerant in the multi-split system from leaking into the room where the refrigerant leak occurs, and ensure that other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 leaking refrigerant does not affect the normal operation of other indoor units 300, thereby improving the reliability of system operation.

[0096] By setting two sections of pipelines and adjusting the connecting pipe openings at both ends of the first pipeline 151 and the second pipeline 152 to control the refrigerant flow direction between the first pipe opening 110, the second pipe opening 120, the third pipe opening 130 and the fourth pipe opening 140, and then controlling the connection and disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230, the structure is simple, easy to operate, and low in cost. It can well block the pipeline vibration and abnormal sound transmission of the indoor unit 300, and improve the noise problem of the indoor unit 300. And avoid the problem of excessive heating of the room, improve the reliability and comfort of the heating operation of the system. Prevent the refrigerant in the multi-split system from leaking into the room where the refrigerant leaks, and ensure that the other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 that leaks the refrigerant does not affect the normal operation of other indoor units 300, and improve the reliability of system operation.

[0097] In some embodiments, reference Figure 2 and Figure 3 As shown, the switching component switches to the first state when the power is on, and switches to the second state when the power is off.

[0098] When the indoor unit 300 is powered on, the controller sends a power-on command to the safety device 100, controlling the switching component to switch to the first state, so that the first pipe opening 110 and the second pipe opening 120 are connected, and the third pipe opening 130 and the fourth pipe opening 140 are connected, thereby controlling the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 to be connected. The refrigerant can circulate between the indoor unit 300 and the outdoor unit 200 through the safety device 100, realizing normal cooling and heating, and ensuring the normal operation of the entire multi-split system.

[0099] When the indoor unit 300 is not needed (standby, temperature shutdown or air supply state), the corresponding expansion valve 210 is closed, and the controller sends a power-off command to the safety device 100. The safety device 100 is in a power-off state, and the switching component switches to the second state. The first pipe port 110 and the second pipe port 120 are not connected, and the third pipe port 130 and the fourth pipe port 140 are not connected. The refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, and the refrigerant cannot pass through, thereby effectively blocking the pipeline vibration and abnormal sound transmission of the indoor unit 300, improving the noise problem of the indoor unit 300, and avoiding the problem of overheating of the room, thereby improving the reliability and comfort of the system heating operation, and preventing the refrigerant in the multi-split system from leaking into the room where the refrigerant leak occurs, and ensuring that other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 leaking refrigerant does not affect the normal operation of other indoor units 300, thereby improving the system operation reliability.

[0100] The power-on status of the switching component corresponds to the power-on status of the indoor unit 300. When the indoor unit 300 operates normally, the switching component is powered on and switched to the first state. When the indoor unit 300 is not needed (standby, temperature shutdown or air supply state), the switching component is powered off and switched to the second state. It can well follow the system operation status to control the connection and disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230, thereby ensuring the reliability of system operation.

[0101] In some embodiments, reference Figure 2 and Figure 3 As shown, the switching component is a valve core component, and the valve core component has a first pipe 151 and a second pipe 152. The valve core component rotates when power is on so that the first pipe 151 connects the first pipe port 110 and the second pipe port 120. The valve core component rotates when power is off so that the second pipe 152 connects the second pipe port 120 and the fourth pipe port 140.

[0102] The valve core assembly is provided with a first pipe 151 and a second pipe 152, which rotates when powered on to connect the first pipe 151 to the second pipe 120, and rotates when powered off to connect the second pipe 152 to the second pipe 120 and the fourth pipe 140. The connecting pipes at both ends of the first pipe 151 and the second pipe 152 are adjusted by rotation to control the flow direction of the refrigerant between the first pipe 110, the second pipe 120, the third pipe 130 and the fourth pipe 140, thereby controlling the connection and disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230. The structure is simple, easy to operate, and low in cost. It can well prevent the pipeline vibration and abnormal sound transmission of the indoor unit 300, improve the noise problem of the indoor unit 300, and avoid the problem of excessive heating of the room, thereby improving the reliability and comfort of the heating operation of the system. Prevent the refrigerant in the multi-split system from leaking into the room where the refrigerant leakage occurs, and ensure that other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 leaking refrigerant does not affect the normal operation of other indoor units 300, thereby improving the system operation reliability.

[0103] Reference Figure 4 As shown, the embodiment of the present application also provides a control method of a multi-split system, which is applied to the aforementioned multi-split system, and the multi-split system also includes a refrigerant leakage detection device corresponding to the indoor unit 300;

[0104] The control method includes but is not limited to the following steps:

[0105] Step S100, when the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration, determining a target indoor unit 300 corresponding to the refrigerant detection device;

[0106] Step S100, controlling the safety device 100 corresponding to the target indoor unit 300 to switch to the second state.

[0107] The refrigerant pipeline of the traditional multi-split system connects the outdoor unit 200 and multiple indoor units 300. Once a refrigerant leak occurs at the indoor heat exchanger of an indoor unit 300, all the refrigerants in the multi-split system will leak into the same room, eventually shutting down for protection, and the indoor units 300 in other rooms will not be able to work normally.

[0108] For the control method of the multi-split system of the embodiment of the present application, in the operation mode of the outdoor unit 200, if the refrigerant leakage detection device corresponding to a room detects a refrigerant leakage, the controller sends a power-off command to the safety device 100 of the corresponding indoor unit 300, the safety device 100 is self-locked when it is powered off, the switching component is in the second state, the first pipe opening 110 and the second pipe opening 120 are not connected, the third pipe opening 130 and the fourth pipe opening 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, the refrigerant cannot pass, the indoor unit 300 is not connected to the outdoor unit 200, the outdoor unit 200 runs without stopping, and the operation of the indoor units 300 in other rooms is not affected. After the leakage is restored, when the system is powered on again, the system resumes normal operation. It can prevent the refrigerant in the multi-split system from leaking into the room where the refrigerant leakage occurs, and ensure that the other indoor units 300 in the multi-split system can operate normally without being affected, so that the indoor unit 300 leaking the refrigerant does not affect the normal operation of other indoor units 300, and improves the reliability of system operation.

[0109] In some embodiments, reference Figure 5 As shown, the control method also includes but is not limited to the following steps:

[0110] Step S300, after the multi-split system is started, determining the target indoor unit 300 operating in the cooling mode or the heating mode;

[0111] Step S400, controlling the safety device 100 corresponding to the target indoor unit 300 to switch to the first state;

[0112] Step S500: When the target indoor unit 300 exits the cooling mode or the heating mode, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state.

[0113] After the multi-split system is started and operated, the target indoor unit 300 operating in cooling mode or heating mode operates normally, and the corresponding safety device 100 switches to the first state, the first pipe opening 110 and the second pipe opening 120 are connected, and the third pipe opening 130 and the fourth pipe opening 140 are connected, thereby controlling the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 to be connected. The refrigerant can circulate between the indoor unit 300 and the outdoor unit 200 through the safety device 100 to achieve normal cooling and heating.

[0114] When the target indoor unit 300 is switched from the heating mode to the shutdown state, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, and the corresponding expansion valve 210 is synchronously moved to the standby opening, which can block the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230. When the target indoor unit 300 is switched from the cooling mode to the shutdown state, the expansion valve 210 corresponding to the target indoor unit 300 is controlled to close, and after the expansion valve 210 is closed for a first preset time, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, thereby blocking the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230. Through step S500, the refrigerant of the indoor unit 300 can be recovered to the circulation system to the greatest extent.

[0115] It should be noted that the first preset time length can be 30 seconds, or can be set to other values ​​according to actual conditions. The specific value of the first preset time length mainly depends on the actual refrigerant recovery rate and cannot be regarded as a limitation of this application.

[0116] In addition, the working principles of the cooling mode and the heating mode of the multi-split system are all existing technologies known to technical personnel in this field. When the target indoor unit 300 is switched from the cooling mode to the shutdown state, it is necessary to control the safety device 100 corresponding to the target indoor unit 300 to switch to the second state after the expansion valve 210 is closed for a first preset time. The reason can be inferred based on the working principles of the cooling mode and the heating mode of the multi-split system, and will not be repeated here.

[0117] In some embodiments, reference Figure 6 As shown, step S500 includes but is not limited to the following steps:

[0118] Step S510, when the target indoor unit 300 changes from the heating mode to the shutdown state, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state;

[0119] Step S520, when the target indoor unit 300 changes from the cooling mode to the shutdown state, the expansion valve 210 corresponding to the target indoor unit 300 is controlled to close, and after the expansion valve 210 is closed for a first preset time, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state.

[0120] When the target indoor unit 300 changes from the heating mode to the shutdown state, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, and the corresponding expansion valve 210 synchronously moves to the standby opening, which can block the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230.

[0121] When the target indoor unit 300 changes from cooling mode to shutdown mode, the expansion valve 210 corresponding to the target indoor unit 300 is controlled to close, and after the expansion valve 210 is closed for a first preset time, the safety device 100 corresponding to the target indoor unit 300 is controlled to switch to the second state, thereby blocking the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230.

[0122] Through step S510 and step S520, the refrigerant of the indoor unit 300 can be recovered into the circulation system to the greatest extent.

[0123] It should be noted that the first preset time length can be 30 seconds, or can be set to other values ​​according to actual conditions. The specific value of the first preset time length mainly depends on the actual refrigerant recovery rate and cannot be regarded as a limitation of this application.

[0124] In some embodiments, reference Figure 7 As shown, the control method also includes but is not limited to the following steps:

[0125] Step S600, when all indoor units 300 are in standby mode, the compressor 250 of the multi-split system is controlled to stop;

[0126] Step S700, after the compressor 250 stops, all the indoor units 300 remain in a standby state within a second preset time period, the compressor 250 is started at a preset operating frequency, all the indoor units 300 are controlled to operate in a cooling mode, the expansion valves 210 corresponding to all the indoor units 300 are controlled to be closed, and all the safety devices 100 are controlled to switch to the first state;

[0127] Step S800, after starting the compressor 250 at a preset operating frequency for a third preset time, all safety devices 100 are controlled to switch to the second state, and the compressor 250 is controlled to stop.

[0128] If all the indoor units 300 are in the standby state, it means that all the indoor units 300 have no energy demand, and the compressor 250 of the multi-split system is controlled to shut down. If all the indoor units 300 remain in the standby state within the second preset time after the compressor 250 shuts down, it means that all the indoor units 300 may not have energy demand in the future, but the refrigerant may still remain in the pipes of the system, resulting in a waste of refrigerant.

[0129] At this time, the compressor 250 is started at a preset operating frequency, all indoor units 300 are controlled to operate in the cooling mode, the expansion valves 210 corresponding to all indoor units 300 are controlled to be closed, and all safety devices 100 are controlled to switch to the first state, so that the first pipe port 110 and the second pipe port 120 are connected, and the third pipe port 130 and the fourth pipe port 140 are connected. At this time, the refrigerant flow direction of the multi-split system is as follows for the side close to the indoor unit 300: from the expansion valve 210 to the first pipe port 110, the second pipe port 120, and the indoor unit 300; from the indoor unit 300 to the fourth pipe port 140, the third pipe port 130, and then back to the outdoor unit 200. At this time, the indoor fan is not turned on. Since the expansion valve 210 is closed and the refrigerant flow direction is single due to the cooling mode, the refrigerant in the system can be recovered to the outdoor unit 200 to the greatest extent, thereby improving the maintainability of the system.

[0130] After the compressor 250 starts for the third preset time, it indicates that the refrigerant has been recovered to the outdoor unit 200 to the maximum extent. At this time, all safety devices 100 are controlled to switch to the second state, the compressor 250 is controlled to stop, the first pipe port 110 and the second pipe port 120 are not connected, the third pipe port 130 and the fourth pipe port 140 are not connected, the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 is disconnected, the refrigerant cannot pass through, and the indoor unit 300 is not connected to the outdoor unit 200, so as to avoid refrigerant leakage.

[0131] It should be noted that the second preset time represents the judgment standard that all indoor units 300 may not be needed in the future, and can be set to 30 minutes, or other values ​​according to actual conditions, and cannot be regarded as a limitation of the present application. In addition, the third preset time represents the judgment standard that the refrigerant has been recovered to the outdoor unit 200 to the greatest extent, and can be set to 1 minute, or other values ​​according to actual conditions, and cannot be regarded as a limitation of the present application.

[0132] In some embodiments, the control method further includes but is not limited to the following steps: when the refrigerant detection device detects that the refrigerant concentration exceeds the preset concentration, the target indoor unit 300 is controlled to issue a refrigerant leakage prompt message. The refrigerant leakage prompt message can serve as a warning to remind the user that the refrigerant concentration has exceeded the standard, the refrigerant has leaked, and there may be safety hazards, which require timely maintenance.

[0133] It should be noted that the refrigerant leakage prompt information can be a display prompt information, or it can be an audio and video alarm information, or simply a sound alarm or a light alarm, all of which can be selected according to actual needs. The specific form of the refrigerant leakage prompt information cannot be regarded as a limitation of this application.

[0134] An embodiment of the present application also provides a controller, comprising at least one processor and a memory for communicating with the at least one processor; the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method as described in the above embodiment.

[0135] According to the safety device 100 and its multi-split system, control method, and controller of the embodiment of the present application, the safety device 100 controls the connection and disconnection of the refrigerant flow path between the indoor heat exchanger and the outdoor heat exchanger 230 by switching between the first state and the second state; when it is detected that the refrigerant concentration in the room of a certain indoor unit 300 exceeds a certain value, the multi-split system can control the safety device 100 to switch to the second state, disconnecting the refrigerant flow path between the indoor heat exchanger of the indoor unit 300 and the outdoor heat exchanger 230, thereby preventing the refrigerant from leaking into the room, ensuring that the other indoor units 300 in the multi-split system can operate normally without being affected; on the other hand, the multi-split system can also cooperate with the startup control of the indoor unit 300 through the first state and the second state of the safety device 100 to improve the problems caused by the residual refrigerant in the indoor unit 300.

[0136] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0137] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A safety device, characterized in that: The switch assembly comprises a first pipe opening, a second pipe opening, a third pipe opening, a fourth pipe opening and a switching assembly, wherein the first pipe opening is connected to a refrigerant pipe opening of an outdoor heat exchanger, the third pipe opening is connected to another refrigerant pipe opening of the outdoor heat exchanger, the second pipe opening is connected to a refrigerant pipe opening of an indoor heat exchanger, the fourth pipe opening is connected to another refrigerant pipe opening of the indoor heat exchanger, and the switching assembly is used to be controlled to switch between a first state and a second state; Wherein, the first state is: the first pipe opening is connected to the second pipe opening, and the third pipe opening is connected to the fourth pipe opening; the second state is: the first pipe opening is not connected to the second pipe opening, and the third pipe opening is not connected to the fourth pipe opening.

2. The safety device according to claim 1, characterized in that: The switching assembly comprises a first pipe and a second pipe. In the first state, the first pipe is connected to the first pipe opening and the second pipe opening, and the second pipe is connected to the third pipe opening and the fourth pipe opening. In the second state, the first pipe communicates with the first pipe opening and the third pipe opening, and the second pipe communicates with the second pipe opening and the fourth pipe opening.

3. The safety device according to claim 1 or 2, characterized in that: The switching component switches to the first state when the power is on, and switches to the second state when the power is off.

4. The safety device according to claim 2, characterized in that: The switching assembly is a valve core assembly, and the valve core assembly opens the first pipeline and the second pipeline. When the power is on, the valve core assembly rotates so that the first pipeline connects the first pipe opening and the second pipe opening. When the power is off, the valve core assembly rotates so that the second pipeline connects the second pipe opening and the fourth pipe opening.

5. A multi-link system, characterized in that: It comprises an outdoor unit, a plurality of indoor units and a plurality of safety devices according to any one of claims 1 to 4, wherein the safety device is arranged between the outdoor heat exchanger of the outdoor unit and the indoor heat exchanger of the indoor unit.

6. The multi-connection system according to claim 5, characterized in that: The multi-split system also includes a refrigerant leakage detection device corresponding to the indoor unit; the multi-split system is used to determine the target indoor unit corresponding to the refrigerant detection device and control the safety device corresponding to the target indoor unit to switch to the second state when the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration.

7. A control method for a multi-link system, characterized in that: Applied to the multi-split system according to claim 5 or 6, the multi-split system further comprises a refrigerant leakage detection device corresponding to the indoor unit; the control method comprises: When the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration, determining a target indoor unit corresponding to the refrigerant detection device; The safety device corresponding to the target indoor unit is controlled to switch to the second state.

8. The control method according to claim 7, characterized in that: The control method further comprises: After the multi-split system is started up, determining a target indoor unit operating in a cooling mode or a heating mode; Controlling the safety device corresponding to the target indoor unit to switch to a first state; When the target indoor unit exits the cooling mode or the heating mode, the safety device corresponding to the target indoor unit is controlled to switch to the second state.

9. The control method according to claim 7, characterized in that: When the target indoor unit exits the cooling mode or the heating mode, controlling the safety device corresponding to the target indoor unit to switch to the second state includes: When the target indoor unit changes from the heating mode to the shutdown state, controlling the safety device corresponding to the target indoor unit to switch to the second state; When the target indoor unit changes from cooling mode to shutdown mode, the expansion valve corresponding to the target indoor unit is controlled to close, and after the expansion valve is closed for a first preset time, the safety device corresponding to the target indoor unit is controlled to switch to the second state.

10. The control method according to claim 7, characterized in that: The control method further comprises: When all the indoor units are in standby mode, the compressor of the multi-split system is controlled to stop; All the indoor units are kept in a standby state within a second preset time after the compressor is stopped, the compressor is started at a preset operating frequency, all the indoor units are controlled to operate in a cooling mode, the expansion valves corresponding to all the indoor units are controlled to be closed, and all the safety devices are controlled to switch to the first state; After the compressor is started at the preset operating frequency for a third preset time, all the safety devices are controlled to switch to the second state, and the compressor is controlled to stop.

11. The control method according to claim 7, characterized in that: The control method further comprises: When the refrigerant detection device detects that the refrigerant concentration exceeds a preset concentration, the target indoor unit is controlled to issue a refrigerant leakage prompt message.

12. A controller, characterized in that It comprises at least one processor and a memory for communicating with the at least one processor; the memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor so that the at least one processor can execute the control method as described in any one of claims 7 to 11.

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