Multi-split system and control method thereof

Abstract

The embodiment of the invention provides a multi-split air conditioner system and a control method thereof, and the multi-split air conditioner system comprises a compressor with an exhaust structure and an air suction port; the first four-way valve is provided with a first valve port, a second valve port, a third valve port and a fourth valve port; the second four-way valve is provided with a fifth valve port, a sixth valve port, a seventh valve port and an eighth valve port; the outdoor heat exchanger is connected with the sixth valve port; the indoor heat exchange module comprises a first refrigerant distribution pipe, a second refrigerant distribution pipe, a third refrigerant distribution pipe and a plurality of indoor heat exchangers, the first refrigerant distribution pipe is connected with the fourth valve port and the first refrigerant ends of the indoor heat exchangers, and the second refrigerant distribution pipe is connected with the eighth valve port and the first refrigerant ends of the indoor heat exchangers; the third refrigerant distribution pipe is connected with the outdoor heat exchanger and the second refrigerant ends of the multiple indoor heat exchangers. And the switch unit comprises a first stop valve, a plurality of second stop valves and a plurality of third stop valves.

Description

Technical Field

[0001] The present application relates to the field of air conditioning technology, and in particular to a multi-split system and a control method thereof. Background Art

[0002] A multi-split system features multiple indoor heat exchangers, each of which can independently operate in different functional modes to meet diverse usage requirements. In related technologies, the switching control structure of a multi-split system is relatively complex, leading to complex switching control logic and the inability to quickly and reliably switch between states. Summary of the Invention

[0003] The embodiments of the present application provide a multi-split system and a control method thereof, which can simplify the switching control structure and switching control logic of the multi-split system and quickly and reliably switch the functional mode of each indoor heat exchanger.

[0004] On the one hand, an embodiment of the present application provides a multi-split system, comprising: a compressor having an exhaust structure and an air intake port; a first four-way valve having a first valve port, a second valve port, a third valve port and a fourth valve port, wherein the first valve port and the second valve port are respectively connected to the exhaust structure, and the third valve port is connected to the air intake port; a second four-way valve having a fifth valve port, a sixth valve port, a seventh valve port and an eighth valve port, wherein the fifth valve port is respectively connected to the exhaust structure and the second valve port, and the seventh valve port is connected to the air intake port; an outdoor heat exchanger, wherein the outdoor heat exchanger is connected to the sixth valve port; an indoor heat exchange module, comprising a first refrigerant distribution pipe, a second refrigerant distribution pipe, a third refrigerant distribution pipe and a plurality of indoor The indoor heat exchanger, the first refrigerant distribution pipe connects the fourth valve port and the first refrigerant ends of the multiple indoor heat exchangers, the second refrigerant distribution pipe connects the eighth valve port and the first refrigerant ends of the multiple indoor heat exchangers, and the third refrigerant distribution pipe connects the outdoor heat exchanger and the second refrigerant ends of the multiple indoor heat exchangers; the switch unit includes a first stop valve, a plurality of second stop valves and a plurality of third stop valves, the first stop valve is arranged between the second valve port and the fifth valve port, the second stop valve is provided between the first refrigerant distribution pipe and the first refrigerant end of the indoor heat exchanger, and the third stop valve is provided between the second refrigerant distribution pipe and the first refrigerant end of the indoor heat exchanger.

[0005] In some embodiments, the multi-split system includes a first throttling device, which is disposed between the third refrigerant distribution pipe and the outdoor heat exchanger.

[0006] In some embodiments, the multi-split system includes a plurality of second throttling devices, and the second throttling devices are provided between the third refrigerant distribution pipe and the second refrigerant end of the indoor heat exchanger.

[0007] In some embodiments, the exhaust structure includes a first exhaust port and a second exhaust port, the first valve port is connected to the first exhaust port, the second valve port is connected to the second exhaust port, and the fifth valve port is connected to the second exhaust port and the second valve port respectively.

[0008] In some embodiments, the exhaust structure includes an exhaust port, and the multi-connected system further includes a fourth stop valve, which is arranged at the front end of the first valve port and is used to control the connection between the first valve port and the exhaust port.

[0009] On the other hand, an embodiment of the present application provides a multi-split system control method for controlling the multi-split system described in any of the above embodiments, the multi-split system control method including: determining, among the multiple indoor heat exchangers, all target indoor heat exchangers with operating requirements and the target functional mode of each of the target indoor heat exchangers; and controlling the on-off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve and the third stop valve according to the target functional mode of each of the target indoor heat exchangers.

[0010] In some embodiments, according to the target functional modes of the plurality of indoor heat exchangers, the on / off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve and the third stop valve are controlled, including: when the target functional modes of each of the target indoor heat exchangers are the cooling functional modes, controlling the first valve port and the second valve port to be connected, the third valve port and the fourth valve port to be connected, the fifth valve port and the sixth valve port to be connected, the seventh valve port and the eighth valve port to be connected, and the first stop valve to be turned on, as well as controlling the second stop valve and the third stop valve connected to each of the target indoor heat exchangers to remain turned on, and controlling the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger to remain turned off.

[0011] In some embodiments, according to the target functional mode of each of the target indoor heat exchangers, the on-off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve and the third stop valve are controlled, including: when the target functional mode of each of the target indoor heat exchangers is a heating functional mode, and the heat exchange demand of any two of the target indoor heat exchangers is the same, the first valve port and the second valve port are controlled to be connected, the third valve port and the fourth valve port are controlled to be connected, the fifth valve port and the eighth valve port are controlled to be connected, the sixth valve port and the seventh valve port are controlled to be connected, and the first stop valve remains cut off, and the second stop valve connected to each of the target indoor heat exchangers is controlled to remain cut off and the third stop valve remains connected, and the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain cut off.

[0012] In some embodiments, according to the target functional mode of each of the target indoor heat exchangers, the on-off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve and the third stop valve are controlled, including: when the target functional mode of each of the target indoor heat exchangers is a heating functional mode, and the heat exchange demand of at least two of the target indoor heat exchangers is different, the first valve port and the fourth valve port are controlled to be connected, the second valve port and the third valve port are controlled to be connected, the fifth valve port and the eighth valve port are controlled to be connected, the sixth valve port and the seventh valve port are controlled to be connected, and the first stop valve remains closed, as well as controlling the second stop valve connected to part of the target indoor heat exchangers to be turned on and the third stop valve to be turned off, and controlling the second stop valve connected to another part of the target indoor heat exchangers to be turned off and the third stop valve to be turned on.

[0013] In some embodiments, the on-off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve and the third stop valve are controlled according to the target functional mode of each of the target indoor heat exchangers, including: when the target functional mode of some of the target indoor heat exchangers is the cooling functional mode and the target functional mode of another part of the target indoor heat exchangers is the heating functional mode, the total heat exchange demand of the multi-split system is determined; when the total heat exchange demand of the multi-split system is heating, the first valve port and the second valve port are controlled to be connected, the third valve port and the fourth valve port are controlled to be connected, the fifth valve port and the eighth valve port are controlled to be connected, the sixth valve port and the seventh valve port are controlled to be connected, and the first stop valve is controlled to be connected, and the third stop valve connected to the target indoor heat exchanger for heating is controlled to be closed, and the second stop valve connected to the target indoor heat exchanger for cooling is controlled to be closed. The third stop valve connected to the target indoor heat exchanger for cooling is closed, and the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain closed; when the total heat exchange demand of the multi-split system is cooling or defrosting without stopping, the first valve port is controlled to be connected to the fourth valve port, the second valve port is controlled to be connected to the third valve port, the fifth valve port is controlled to be connected to the sixth valve port, the seventh valve port is controlled to be connected to the eighth valve port, and the first stop valve is closed, and the second stop valve connected to the target indoor heat exchanger for heating is controlled to be connected, and the third stop valve connected to the target indoor heat exchanger for heating is controlled to be closed, and the third stop valve connected to the target indoor heat exchanger for cooling is controlled to be connected, and the second stop valve connected to the target indoor heat exchanger for cooling is controlled to be closed, and the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain closed.

[0014] The embodiment of the present application sets two four-way valves, a first stop valve, a second stop valve and a third stop valve, and adjusts the on-off states of the two four-way valves, the first stop valve, the second stop valve and the third stop valve to achieve fast and reliable switching between the functional modes of each indoor heat exchanger. The switching control structure has a small number of components and a relatively simple switching control logic, which can effectively simplify the switching control structure and switching control logic of the multi-split system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0016] Figure 1 This is a connection structure diagram of a multi-connection system provided in some embodiments of the present application;

[0017] Figure 2 This is another connection structure diagram of a multi-connection system provided in some embodiments of the present application;

[0018] Figure 3 This is a usage state diagram of a multi-connection system provided in some embodiments of the present application;

[0019] Figure 4 This is another usage state diagram of the multi-connected system provided in some embodiments of the present application;

[0020] Figure 5 This is another usage state diagram of the multi-connection system provided in some embodiments of the present application;

[0021] Figure 6 This is another usage state diagram of the multi-connection system provided in some embodiments of the present application;

[0022] Figure 7 This is another usage state diagram of the multi-connection system provided in some embodiments of the present application;

[0023] Figure 8 is a flow chart of a multi-connected system control method provided by some embodiments of the present application;

[0024] Figure 9 is another flow chart of a multi-connected system control method provided by some embodiments of the present application;

[0025] Figure 10 This is another flow chart of the multi-connected system control method provided in some embodiments of the present application.

[0026] Description of main component symbols:

[0027] 1-Multi-connected system, 10-Compressor, 11-First exhaust port, 12-Second exhaust port, 20-First four-way valve, 21-First valve port, 22-Second valve port, 23-Third valve port, 24-Fourth valve port, 30-Second four-way valve, 31-Fifth valve port, 32-Sixth valve port, 33-Seventh valve port, 34-Eighth valve port, 40-Outdoor heat exchanger, 50-Indoor heat exchange module, 51-First refrigerant distribution pipe, 52-Second refrigerant distribution pipe, 53-Third refrigerant distribution pipe, 54-Indoor heat exchanger, 61-First stop valve, 62-Second stop valve, 63-Third stop valve, 64-Fourth stop valve, 70-First throttling device, 80-Second throttling device. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0029] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present application, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0030] “A and / or B” includes the following three combinations: A only, B only, and a combination of A and B.

[0031] The use of "suitable for" or "configured to" in this application is intended to be open and inclusive language, and does not exclude devices that are adapted or configured to perform additional tasks or steps. In addition, the use of "based on" is intended to be open and inclusive, as a process, step, calculation, or other action that is "based on" one or more stated conditions or values ​​may, in practice, be based on additional conditions or values ​​beyond those stated.

[0032] In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described in this application as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is given to enable any person skilled in the art to implement and use the present application. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art can recognize that the present application can be implemented without using these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present application with unnecessary details. Therefore, the present application is not intended to be limited to the embodiments shown, but is consistent with the widest scope consistent with the principles and features disclosed in this application.

[0033] like Figures 1 to 7 As shown, on the one hand, an embodiment of the present application provides a multi-split system 1, which includes a compressor 10, a first four-way valve 20, a second four-way valve 30, an outdoor heat exchanger 40, an indoor heat exchange module 50 and a switch unit, which can simplify the switching control structure and switching control logic of the multi-split system 1, and quickly and reliably switch the functional mode of each indoor heat exchanger 54.

[0034] Compressor 10 has an exhaust structure and an intake port. The exhaust structure is used to discharge the high-temperature, high-pressure gaseous refrigerant generated by compressor 10, and the intake port is used to recover the gaseous refrigerant in the refrigerant circulation loop. The type of compressor 10 can be determined based on actual needs and is not limited in this embodiment of the present application.

[0035] The first four-way valve 20 has a first valve port 21, a second valve port 22, a third valve port 23, and a fourth valve port 24. The first valve port 21 and the second valve port 22 are respectively connected to the exhaust structure, and the third valve port 23 is connected to the intake port. The first four-way valve 20 can have two on-off states. By changing the on-off state of the first four-way valve 20, the first four-way valve 20 can be switched between the two on-off states. In the first on-off state, the first valve port 21 and the second valve port 22 are connected, and the third valve port 23 and the fourth valve port 24 are connected. In the second on-off state, the first valve port 21 and the fourth valve port 24 are connected, and the second valve port 22 and the third valve port 23 are connected.

[0036] The second four-way valve 30 has a fifth valve port 31, a sixth valve port 32, a seventh valve port 33, and an eighth valve port 34. The fifth valve port 31 is connected to the exhaust structure and the second valve port 22, respectively. The sixth valve port 32 is connected to the outdoor heat exchanger 40. The seventh valve port 33 is connected to the intake port. The second four-way valve 30 can have two on-off states. By changing the on-off state of the second four-way valve 30, the second four-way valve 30 can be switched between the two on-off states. In the first on-off state, the fifth valve port 31 is connected to the sixth valve port 32, and the seventh valve port 33 is connected to the eighth valve port 34. In the second on-off state, the fifth valve port 31 is connected to the eighth valve port 34, and the sixth valve port 32 is connected to the seventh valve port 33.

[0037] The indoor heat exchange module 50 includes a first refrigerant distribution pipe 51, a second refrigerant distribution pipe 52, a third refrigerant distribution pipe 53, and multiple indoor heat exchangers 54. Each indoor heat exchanger 54 has a first refrigerant end and a second refrigerant end. The first refrigerant distribution pipe 51 connects the fourth valve port 24 and the first refrigerant ends of the multiple indoor heat exchangers 54, the second refrigerant distribution pipe 52 connects the eighth valve port 34 and the first refrigerant ends of the multiple indoor heat exchangers 54, and the third refrigerant distribution pipe 53 connects the outdoor heat exchanger 40 and the second refrigerant ends of the multiple indoor heat exchangers 54. In other words, the first refrigerant end of each indoor heat exchanger 54 is connected to the first refrigerant distribution pipe 51 and the second refrigerant distribution pipe 52, respectively, and the second refrigerant end of each indoor heat exchanger 54 is connected to the third refrigerant distribution pipe 53. Multiple indoor heat exchangers 54 can be set in the same indoor space to jointly meet the cooling / heating function needs of the same indoor space; or, multiple indoor heat exchangers 54 can also be set in different indoor spaces to respectively meet the cooling / heating function needs of different indoor spaces.

[0038] The switch unit includes a first stop valve 61, multiple second stop valves 62, and multiple third stop valves 63. The first stop valve 61 is arranged between the second valve port 22 and the fifth valve port 31, and is used to control the on-off relationship between the second valve port 22 and the fifth valve port 31. A second stop valve 62 is provided between the first refrigerant distribution pipe 51 and the first refrigerant end of the indoor heat exchanger 54, and the second stop valve 62 is used to control the on-off relationship between the first refrigerant distribution pipe 51 and the first refrigerant end of the indoor heat exchanger 54. A third stop valve 63 is provided between the second refrigerant distribution pipe 52 and the first refrigerant end of the indoor heat exchanger 54, and the third stop valve 63 is used to control the on-off relationship between the second refrigerant distribution pipe 52 and the first refrigerant end of the indoor heat exchanger 54.

[0039] In this way, by controlling the on / off states of the first four-way valve 20, the second four-way valve 30, the first stop valve 61, the second stop valve 62, and the third stop valve 63, the flow direction of the refrigerant discharged from the compressor 10 and the connection state between each indoor heat exchanger 54 can be quickly switched, so that each indoor heat exchanger 54 can independently achieve the required functional mode, such as cooling / heating / defrosting, to meet different usage requirements. Compared with the related art, the multi-split system 1 provided in the embodiment of the present application only needs to be provided with two four-way valves, the first stop valve 61, the second stop valve 62, and the third stop valve 63. By adjusting the on / off states of the two four-way valves, the first stop valve 61, the second stop valve 62, and the third stop valve 63, fast and reliable switching between the functional modes of each indoor heat exchanger 54 can be achieved. The switching control structure has a small number of components and the switching control logic is relatively simple, which can effectively simplify the switching control structure and switching control logic of the multi-split system 1.

[0040] In some embodiments, the VRF system 1 may include a first throttling device 70. The first throttling device 70 is disposed between the third refrigerant distribution pipe 53 and the outdoor heat exchanger 40 and can be used to throttle the refrigerant flowing between the third refrigerant distribution pipe 53 and the outdoor heat exchanger 40. The type of the first throttling device 70 can be determined based on actual needs and can employ various types, such as an expansion valve and a capillary tube, and is not limited in this embodiment of the present application.

[0041] In some embodiments, the multi-split system 1 may include multiple second throttling devices 80. A second throttling device 80 is provided between the third refrigerant distribution pipe 53 and the second refrigerant end of the indoor heat exchanger 54. That is, a second throttling device 80 is provided between the third refrigerant distribution pipe 53 and multiple indoor heat exchangers 54. Each second throttling device 80 is used to throttle the refrigerant flowing between the third refrigerant distribution pipe 53 and the corresponding indoor heat exchanger 54. The type of the second throttling device 80 can be determined according to actual needs, and can adopt different types such as expansion valves and capillary tubes, which are not limited in this embodiment of the present application.

[0042] The type of exhaust structure can be determined according to actual needs, and different structural types such as single exhaust and multiple exhaust can be adopted, which is not limited in the embodiment of the present application. Figure 1 、 Figures 3 to 7As shown, in some embodiments, the exhaust structure can adopt a multi-exhaust structure type, which correspondingly includes a first exhaust port 11 and a second exhaust port 12. The first valve port 21 is connected to the first exhaust port 11, the second valve port 22 is connected to the second exhaust port 12, and the fifth valve port 31 is connected to the second exhaust port 12 and the second valve port 22 respectively. In this way, when the first stop valve 61 remains shut off, the compressor 10 can discharge the high-temperature and high-pressure gaseous refrigerant to the first valve port 21 of the first four-way valve 20 through the first exhaust port 11, and discharge the high-temperature and high-pressure gaseous refrigerant to the fifth valve port 31 of the second four-way valve 30 through the second exhaust port 12, so that the multi-split system 1 has two controllable high pressures, thereby balancing the heating requirements of different indoor heat exchangers 54 under different conditions and improving user comfort.

[0043] like Figure 2 As shown, in other embodiments, the exhaust structure can adopt a single exhaust structure type, correspondingly including a single exhaust port. The multi-split system 1 can also include a fourth stop valve 64, which is disposed at the front end of the first valve port 21 and is used to control the flow between the first valve port 21 and the exhaust port. In this way, when the first stop valve 61 remains closed and the fourth stop valve 64 remains open, the compressor 10 can discharge high-temperature, high-pressure gaseous refrigerant through the exhaust port to the first valve port 21 of the first four-way valve 20, and discharge high-temperature, high-pressure gaseous refrigerant through the exhaust port to the fifth valve port 31 of the second four-way valve 30. This allows the multi-split system 1 to have two controllable high pressures, thereby balancing the heating needs of different indoor heat exchangers 54 under different circumstances and improving user comfort. Furthermore, the opening of the fourth stop valve 64 can be adjusted to adjust the refrigerant flow to the first valve port 21 of the first four-way valve 20 and the refrigerant flow to the fifth valve port 31 of the second four-way valve 30, thereby controlling the pressure states of the two controllable high pressures.

[0044] like Figures 1 to 8 As shown, on the other hand, an embodiment of the present application provides a multi-split system 1 control method for controlling the multi-split system 1 of any of the above embodiments, and the multi-split system 1 control method includes S10 to S20.

[0045] S10: Among the plurality of indoor heat exchangers 54, all target indoor heat exchangers having operation requirements and target functional modes of the respective target indoor heat exchangers are determined.

[0046] Here, the target indoor heat exchanger is the indoor heat exchanger 54 with an operating requirement, while the indoor heat exchanger 54 without an operating requirement is not considered a target indoor heat exchanger. After all target indoor heat exchangers are determined, the target functional mode of each target indoor heat exchanger can be further determined. The target functional mode may include a cooling function mode, a heating function mode, and other types, and can be determined based on the usage needs of the target user of the target indoor heat exchanger.

[0047] S20 : ​​Controlling the on / off states of the first four-way valve 20 , the second four-way valve 30 , the first stop valve 61 , the second stop valve 62 and the third stop valve 63 according to the target functional mode of each target indoor heat exchanger.

[0048] According to the target functional mode of each target indoor heat exchanger, the target on-off states of the first four-way valve 20, the second four-way valve 30, the first stop valve 61, the second stop valve 62 and the third stop valve 63 can be comprehensively determined, and then the on-off states of the first four-way valve 20, the second four-way valve 30, the first stop valve 61, the second stop valve 62 and the third stop valve 63 are switched according to the corresponding target on-off states, so that each target indoor heat exchanger can be quickly switched to the corresponding target functional mode to meet the usage needs of the target users of each target indoor heat exchanger.

[0049] like Figure 9 As shown, in some embodiments, S20 may include S21.

[0050] S21: When the target function mode of each target indoor heat exchanger is the cooling function mode, the first valve port 21 and the second valve port 22 are controlled to be connected, the third valve port 23 and the fourth valve port 24 are controlled to be connected, the fifth valve port 31 and the sixth valve port 32 are controlled to be connected, the seventh valve port 33 and the eighth valve port 34 are controlled to be connected, the first stop valve 61 is controlled to be turned on, and the second stop valve 62 and the third stop valve 63 connected to each target indoor heat exchanger are controlled to remain turned on, and the second stop valve 62 and the third stop valve 63 connected to other indoor heat exchangers 54 except the target indoor heat exchanger are controlled to remain turned off.

[0051] like Figure 3 As shown, part of the refrigerant discharged from the exhaust structure of the compressor 10 can flow to the fifth valve port 31 through the first valve port 21 and the second valve port 22 in sequence, while another part of the refrigerant can flow directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, all of the refrigerant discharged from the exhaust structure of the compressor 10 can flow directly to the fifth valve port 31 and then flow into the second four-way valve 30 through the fifth valve port 31.

[0052] Exemplarily, the exhaust structure may include the first exhaust port 11 and the second exhaust port 12. When the four-way valve and the shut-off valve are in the on-off control state, the refrigerant discharged from the first exhaust port 11 may flow to the fifth valve port 31 through the first valve port 21, the second valve port 22, and the first shut-off valve 61 in sequence. The refrigerant discharged from the second exhaust port 12 may flow directly to the fifth valve port 31. After the two portions of refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0053] As another example, the exhaust structure may include an exhaust port and a fourth shut-off valve 64. Here, the fourth shut-off valve 64 may be controlled to be shut off so that all the refrigerant discharged from the exhaust port of the compressor 10 can flow directly to the fifth valve port 31 and flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, the fourth shut-off valve 64 may be controlled to be open so that part of the refrigerant discharged from the exhaust port of the compressor 10 flows to the fifth valve port 31 in sequence through the fourth shut-off valve 64, the first valve port 21, the second valve port 22 and the first shut-off valve 61, and another part of the refrigerant discharged from the exhaust port of the compressor 10 flows directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0054] Furthermore, the refrigerant flowing into the second four-way valve 30 can flow through the sixth valve port 32, the outdoor heat exchanger 40, and the third refrigerant distribution pipe 53 in sequence to enter each target indoor heat exchanger. Then, after being discharged from each target indoor heat exchanger, it is divided into the first refrigerant distribution pipe 51 and the second refrigerant distribution pipe 52. The refrigerant in the first refrigerant distribution pipe 51 can return to the suction port of the compressor 10 in sequence through the fourth valve port 24 and the third valve port 23. The refrigerant in the second refrigerant distribution pipe 52 can return to the suction port of the compressor 10 in sequence through the eighth valve port 34 and the seventh valve port 33, so that each target indoor heat exchanger can achieve the cooling function. During this process, the second stop valve 62 and the third stop valve 63 connected to the other indoor heat exchangers 54 except the target indoor heat exchanger remain closed, preventing the refrigerant from entering the indoor heat exchangers 54 that do not have an operating demand, so that the indoor heat exchangers 54 that do not have an operating demand remain in a shutdown state.

[0055] In some embodiments, S20 may include S22.

[0056] S22: When the target function mode of each target indoor heat exchanger is a heating function mode, and the heat exchange demand of any two target indoor heat exchangers is the same, the first valve port 21 and the second valve port 22 are controlled to be connected, the third valve port 23 and the fourth valve port 24 are controlled to be connected, the fifth valve port 31 and the eighth valve port 34 are controlled to be connected, the sixth valve port 32 and the seventh valve port 33 are controlled to be connected, the first stop valve 61 is controlled to remain closed, and the second stop valve 62 connected to each target indoor heat exchanger is controlled to remain closed, the third stop valve 63 is controlled to remain connected, and the second stop valve 62 and the third stop valve 63 connected to other indoor heat exchangers 54 except the target indoor heat exchanger are controlled to remain closed.

[0057] Here, when the heat exchange requirements of the two target indoor heat exchangers are equal, or the absolute value of the difference between the heat exchange requirements of the two target indoor heat exchangers is less than or equal to the deviation threshold, it can be considered that the heat exchange requirements of the two target indoor heat exchangers are the same. When the absolute value of the difference between the heat exchange requirements of the two target indoor heat exchangers is greater than the deviation threshold, it can be considered that the heat exchange requirements of the two target indoor heat exchangers are different. At this time, the on-off state control action such as S22 can be executed to make the multi-split system 1 appear as follows Figure 4 The on and off status is shown.

[0058] like Figure 4 As shown, in the above-mentioned on-off state, part of the refrigerant discharged from the exhaust structure of the compressor 10 can flow to the fifth valve port 31 through the first valve port 21 and the second valve port 22 in sequence, and another part of the refrigerant can flow directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, all of the refrigerant discharged from the exhaust structure of the compressor 10 can flow directly to the fifth valve port 31 and flow into the second four-way valve 30 through the fifth valve port 31.

[0059] Exemplarily, the exhaust structure may include the first exhaust port 11 and the second exhaust port 12. When the four-way valve and the shut-off valve are in the on-off control state, the refrigerant discharged from the first exhaust port 11 may flow to the fifth valve port 31 through the first valve port 21, the second valve port 22, and the first shut-off valve 61 in sequence. The refrigerant discharged from the second exhaust port 12 may flow directly to the fifth valve port 31. After the two portions of refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0060] As another example, the exhaust structure may include an exhaust port and a fourth shut-off valve 64. Here, the fourth shut-off valve 64 may be controlled to be shut off so that all the refrigerant discharged from the exhaust port of the compressor 10 can flow directly to the fifth valve port 31 and flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, the fourth shut-off valve 64 may be controlled to be open so that part of the refrigerant discharged from the exhaust port of the compressor 10 flows to the fifth valve port 31 in sequence through the fourth shut-off valve 64, the first valve port 21, the second valve port 22 and the first shut-off valve 61, and another part of the refrigerant discharged from the exhaust port of the compressor 10 flows directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0061] Furthermore, the refrigerant flowing into the second four-way valve 30 can flow through the eighth valve port 34, the second refrigerant distribution pipe 52, and the third stop valve 63 connected to each target indoor heat exchanger in sequence, and then enter each target indoor heat exchanger. It is then discharged from each target indoor heat exchanger and returns to the suction port of the compressor 10 through the third refrigerant distribution pipe 53, the second valve port 22, and the third valve port 23 in sequence, so that each target indoor heat exchanger can achieve the heating function. During this process, the second stop valve 62 and the third stop valve 63 connected to the indoor heat exchangers 54 other than the target indoor heat exchanger remain closed, preventing the refrigerant from entering the indoor heat exchangers 54 that do not need to operate, thereby keeping the indoor heat exchangers 54 that do not need to operate in a shutdown state.

[0062] In some embodiments, S20 may include S23.

[0063] S23: When the target function mode of each target indoor heat exchanger is a heating function mode, and the heat exchange demand of at least two target indoor heat exchangers is different, the first valve port 21 and the fourth valve port 24 are controlled to be connected, the second valve port 22 and the third valve port 23 are controlled to be connected, the fifth valve port 31 and the eighth valve port 34 are controlled to be connected, the sixth valve port 32 and the seventh valve port 33 are controlled to be connected, the first stop valve 61 remains closed, and the second stop valve 62 connected to part of the target indoor heat exchangers is controlled to be opened and the third stop valve 63 is closed, and the second stop valve 62 connected to another part of the target indoor heat exchangers is controlled to be closed and the third stop valve 63 is controlled to be opened.

[0064] When the heat exchange requirements of at least two target indoor heat exchangers are different, it can be determined that at least two target indoor heat exchangers need to be controlled to obtain different heating effects. At this time, the on-off state control action such as S23 can be executed to make the multi-split system 1 appear as follows: Figure 5 As shown in the on-off state. Figure 5 As shown, in the above-mentioned on-off state, since the first stop valve 61 remains cut off, the first four-way valve 20 and the second four-way valve 30 are isolated from each other and present a parallel relationship.

[0065] Correspondingly, part of the refrigerant discharged from the exhaust structure of the compressor 10 can pass through the first valve port 21, the fourth valve port 24, the first refrigerant distribution pipe 51, and the second stop valve 62 connected to the target indoor heat exchanger with the first heat exchange demand in sequence, and then enter the target indoor heat exchanger with the first heat exchange demand, and then be discharged from the target indoor heat exchanger with the first heat exchange demand and pass through the third refrigerant distribution pipe 53, the second valve port 22 and the third valve port 23 in sequence to return to the intake port of the compressor 10, so that the target indoor heat exchanger with the first heat exchange demand can achieve the heating effect corresponding to the first heat exchange demand. Another part of the refrigerant discharged from the exhaust structure of the compressor 10 can pass through the fifth valve port 31, the eighth valve port 34, the second refrigerant distribution pipe 52, and the second stop valve 62 connected to the target indoor heat exchanger with the second heat exchange demand in sequence, and then enter the target indoor heat exchanger with the second heat exchange demand, and then be discharged from the target indoor heat exchanger with the second heat exchange demand and pass through the third refrigerant distribution pipe 53, the second valve port 22 and the third valve port 23 in sequence to return to the intake port of the compressor 10, so that the target indoor heat exchanger with the second heat exchange demand can achieve the heating effect corresponding to the second heat exchange demand.

[0066] When the exhaust structure includes the above-mentioned first exhaust port 11 and second exhaust port 12, the exhaust pressures of the first exhaust port 11 and the second exhaust port 12 can be controlled independently of each other, so that the compressor 10 can provide two refrigerant paths with independently controllable pressures through the first exhaust port 11 and the second exhaust port 12. One refrigerant path flows to the target indoor heat exchanger with a first heat exchange demand through the first exhaust port 11, the first four-way valve 20, and the first refrigerant distribution pipe 51, so as to drive the target indoor heat exchanger with the first heat exchange demand to achieve a heating effect corresponding to the first heat exchange demand; the other refrigerant path flows to the target indoor heat exchanger with a second heat exchange demand through the second exhaust port 12, the second four-way valve 30, and the second refrigerant distribution pipe 52, so as to drive the target indoor heat exchanger with the second heat exchange demand to achieve a heating effect corresponding to the second heat exchange demand. Since the flow rates and pressures of the two refrigerant paths are independently controllable, the target indoor heat exchanger with the first heat exchange demand and the target indoor heat exchanger with the second heat exchange demand can be independently controlled to achieve different heating effects.

[0067] like Figure 10 As shown, in some embodiments, S20 may include S241 to S243.

[0068] S241: When the target functional modes of some target indoor heat exchangers are cooling functional modes and the target functional modes of another target indoor heat exchangers are heating functional modes, determining the total heat exchange demand of the multi-split system 1.

[0069] Here, the heat exchange demand for each target indoor heat exchanger can be determined. The heat exchange demand for a target indoor heat exchanger operating in cooling mode is a negative value, while the heat exchange demand for a target indoor heat exchanger operating in heating mode is a positive value. By summing the heat exchange demands of each target indoor heat exchanger, the total heat exchange demand for multi-split system 1 can be determined. If the total heat exchange demand for multi-split system 1 is a positive value, the total heat exchange demand for multi-split system 1 can be determined to be heating; if the total heat exchange demand for multi-split system 1 is a negative value, the total heat exchange demand for multi-split system 1 can be determined to be cooling or non-stop defrosting. Non-stop defrosting means that the target indoor heat exchanger is still controlled to operate in heating mode while the outdoor unit is defrosting.

[0070] S242: When the total heat exchange demand of the multi-split system 1 is heating, the first valve port 21 and the second valve port 22 are controlled to be connected, the third valve port 23 and the fourth valve port 24 are controlled to be connected, the fifth valve port 31 and the eighth valve port 34 are controlled to be connected, the sixth valve port 32 and the seventh valve port 33 are controlled to be connected, the first stop valve 61 is controlled to be connected, and the third stop valve 63 connected to the target indoor heat exchanger for heating is controlled to be connected, and the second stop valve 62 connected to the target indoor heat exchanger for heating is controlled to be closed, and the second stop valve 62 connected to the target indoor heat exchanger for cooling is controlled to be connected, and the third stop valve 63 connected to the target indoor heat exchanger for cooling is controlled to be closed, and the second stop valve 62 and the third stop valve 63 connected to other indoor heat exchangers 54 except the target indoor heat exchanger are controlled to remain closed.

[0071] When the total heat exchange demand of the multi-split system 1 is heating, it can be determined that the heating demand of the multi-split system 1 is greater than the cooling demand. At this time, the on-off state control action such as S242 can be executed to make the multi-split system 1 as shown in FIG. Figure 6 As shown in the on-off state. Figure 6 As shown, in the above-mentioned on-off state, part of the refrigerant discharged from the exhaust structure of the compressor 10 can flow to the fifth valve port 31 through the first valve port 21 and the second valve port 22 in sequence, and another part of the refrigerant can flow directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, all of the refrigerant discharged from the exhaust structure of the compressor 10 can flow directly to the fifth valve port 31 and flow into the second four-way valve 30 through the fifth valve port 31.

[0072] Exemplarily, the exhaust structure may include the first exhaust port 11 and the second exhaust port 12. When the four-way valve and the shut-off valve are in the on-off control state, the refrigerant discharged from the first exhaust port 11 may flow to the fifth valve port 31 through the first valve port 21, the second valve port 22, and the first shut-off valve 61 in sequence. The refrigerant discharged from the second exhaust port 12 may flow directly to the fifth valve port 31. After the two portions of refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0073] As another example, the exhaust structure may include an exhaust port and a fourth shut-off valve 64. Here, the fourth shut-off valve 64 may be controlled to be shut off so that all the refrigerant discharged from the exhaust port of the compressor 10 can flow directly to the fifth valve port 31 and flow into the second four-way valve 30 through the fifth valve port 31. Alternatively, the fourth shut-off valve 64 may be controlled to be open so that part of the refrigerant discharged from the exhaust port of the compressor 10 flows to the fifth valve port 31 in sequence through the fourth shut-off valve 64, the first valve port 21, the second valve port 22 and the first shut-off valve 61, and another part of the refrigerant discharged from the exhaust port of the compressor 10 flows directly to the fifth valve port 31. After the two parts of the refrigerant converge, they flow into the second four-way valve 30 through the fifth valve port 31.

[0074] Furthermore, the refrigerant flowing into the second four-way valve 30 can flow through the eighth valve port 34, the second refrigerant distribution pipe 52, and the third stop valve 63 connected to the target indoor heat exchanger for heating, and then enter the target indoor heat exchanger for heating. The refrigerant is condensed in the target indoor heat exchanger for heating, so that the target indoor heat exchanger for heating can achieve the heating function. The target indoor heat exchanger discharges the refrigerant into the third refrigerant distribution pipe 53, which distributes the refrigerant. A portion of the refrigerant passes through the outdoor heat exchanger 40, the sixth valve port 32, and the seventh valve port 33 and returns to the suction port of the compressor 10. The remaining portion enters the target indoor heat exchanger for cooling to perform evaporative cooling, so that the target indoor heat exchanger for cooling can achieve the cooling function. After evaporative cooling, the refrigerant passes through the first refrigerant distribution pipe 51, the fourth valve port 24, and the third valve port 23 and returns to the suction port of the compressor 10. During this process, the second stop valve 62 and the third stop valve 63 connected to other indoor heat exchangers 54 except the target indoor heat exchanger remain closed to prevent the refrigerant from entering the indoor heat exchanger 54 that has no operating requirements, so that the indoor heat exchanger 54 that has no operating requirements remains in a shutdown state.

[0075] In this way, the refrigerant discharged from the compressor 10 first enters the target indoor heat exchanger for heating to be condensed and heated, so that the target indoor heat exchanger for heating can achieve better heating function and meet the higher heating requirements of the multi-split system 1; the refrigerant after condensation enters the target indoor heat exchanger for cooling again to be evaporated and cooled, so that the target indoor heat exchanger for cooling can achieve cooling function and meet the lower heating requirements of the multi-split system 1.

[0076] S243: When the total heat exchange demand of the multi-split system 1 is cooling or non-stop defrosting, the first valve port 21 and the fourth valve port 24 are controlled to be connected, the second valve port 22 and the third valve port 23 are controlled to be connected, the fifth valve port 31 and the sixth valve port 32 are controlled to be connected, the seventh valve port 33 and the eighth valve port 34 are controlled to be connected, and the first stop valve 61 is controlled to be closed. The second stop valve 62 connected to the target indoor heat exchanger for heating is controlled to be connected, and the third stop valve 63 connected to the target indoor heat exchanger for heating is controlled to be closed. The third stop valve 63 connected to the target indoor heat exchanger for cooling is controlled to be connected, and the second stop valve 62 connected to the target indoor heat exchanger for cooling is controlled to be closed. The second stop valve 62 and the third stop valve 63 connected to other indoor heat exchangers 54 except the target indoor heat exchanger are controlled to remain closed.

[0077] When the total heat exchange demand of the multi-split system 1 is cooling, it can be determined that the cooling demand of the multi-split system 1 is greater than the heating demand, or when some target indoor heat exchangers are heating, the outdoor heat exchanger 40 has a need for non-stop defrosting. At this time, the on-off state control action such as S243 can be executed to make the multi-split system 1 as shown in FIG. Figure 7 As shown in the on-off state. Figure 7 As shown, in the above-mentioned on-off state, since the first stop valve 61 remains cut off, the first four-way valve 20 and the second four-way valve 30 are isolated from each other and present a parallel relationship.

[0078] Accordingly, the first portion of refrigerant discharged from the exhaust structure of the compressor 10 can sequentially pass through the first valve port 21, the fourth valve port 24, the first refrigerant distribution pipe 51, and the second shut-off valve 62 connected to the target indoor heat exchanger for heating, and then enter the target indoor heat exchanger for heating, so that the target indoor heat exchanger for heating can achieve the heating function. The target indoor heat exchanger for heating then discharges the refrigerant into the third refrigerant distribution pipe 53. The second portion of refrigerant discharged from the exhaust structure of the compressor 10 can sequentially pass through the fifth valve port 31 and the sixth valve port 32 to flow into the outdoor heat exchanger 40 for condensation. When the outdoor heat exchanger 40 needs to defrost, the outdoor heat exchanger 40 is defrosted without stopping. The refrigerant condensed by the outdoor heat exchanger 40 enters the third refrigerant distribution pipe 53 and merges with the first portion of refrigerant. The third refrigerant distribution pipe 53 distributes the merged refrigerant to the target indoor heat exchanger for cooling, causing the refrigerant to evaporate and cool in the target indoor heat exchanger for cooling, so that the target indoor heat exchanger for cooling can achieve the cooling function. The refrigerant is then discharged from the target indoor heat exchanger for cooling and returns to the suction port of the compressor 10 through the second refrigerant distribution pipe 52, the eighth valve port 34, and the seventh valve port 33 in sequence. When the exhaust structure includes the above-mentioned first exhaust port 11 and the second exhaust port 12, the first portion of the refrigerant can be discharged to the first valve port 21 of the first four-way valve 20 through the first exhaust port 11, and the second portion of the refrigerant can be discharged to the fifth valve port 31 of the second four-way valve 30 through the second exhaust port 12.

[0079] In this way, the first part of the refrigerant discharged by the compressor 10 is condensed and heated in the target indoor heat exchanger for heating to realize the heating function, and the second part of the refrigerant is condensed in the outdoor heat exchanger 40 to defrost the outdoor heat exchanger 40 without stopping when there is a defrosting demand in the outdoor heat exchanger 40. After the first part of the refrigerant and the second part of the refrigerant are combined, they are evaporated and cooled in the target indoor heat exchanger for cooling, so that all the refrigerant discharged by the compressor 10 can be used to realize the cooling function, thereby matching the total heat exchange demand of the multi-split system 1 for cooling.

[0080] The above is a detailed introduction to the multi-connected system and its control method provided by the embodiments of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea; at the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. A multi-connection system, characterized in that: include: A compressor having an exhaust structure and an air intake; a first four-way valve having a first valve port, a second valve port, a third valve port, and a fourth valve port, wherein the first valve port and the second valve port are respectively connected to the exhaust structure, and the third valve port is connected to the intake port; a second four-way valve having a fifth valve port, a sixth valve port, a seventh valve port, and an eighth valve port, wherein the fifth valve port is connected to the exhaust structure and the second valve port, respectively, and the seventh valve port is connected to the intake port; an outdoor heat exchanger, the outdoor heat exchanger being connected to the sixth valve port; The indoor heat exchange module includes a first refrigerant distribution pipe, a second refrigerant distribution pipe, a third refrigerant distribution pipe and a plurality of indoor heat exchangers, wherein the first refrigerant distribution pipe is connected to the fourth valve port and the first refrigerant ends of the plurality of indoor heat exchangers, the second refrigerant distribution pipe is connected to the eighth valve port and the first refrigerant ends of the plurality of indoor heat exchangers, and the third refrigerant distribution pipe is connected to the outdoor heat exchanger and the second refrigerant ends of the plurality of indoor heat exchangers; The switch unit includes a first stop valve, multiple second stop valves and multiple third stop valves, the first stop valve is arranged between the second valve port and the fifth valve port, the second stop valve is arranged between the first refrigerant distribution pipe and the first refrigerant end of the indoor heat exchanger, and the third stop valve is arranged between the second refrigerant distribution pipe and the first refrigerant end of the indoor heat exchanger.

2. The multi-connection system according to claim 1, characterized in that: The multi-split system includes a first throttling device, which is arranged between the third refrigerant distribution pipe and the outdoor heat exchanger.

3. The multi-connection system according to claim 1, characterized in that: The multi-split system includes a plurality of second throttling devices, and the second throttling devices are provided between the third refrigerant distribution pipe and the second refrigerant end of the indoor heat exchanger.

4. The multi-connection system according to claim 1, characterized in that: The exhaust structure includes a first exhaust port and a second exhaust port, the first valve port is connected to the first exhaust port, the second valve port is connected to the second exhaust port, and the fifth valve port is connected to the second exhaust port and the second valve port respectively.

5. The multi-connection system according to claim 1, characterized in that: The exhaust structure includes an exhaust port, and the multi-connected system also includes a fourth stop valve. The fourth stop valve is arranged at the front end of the first valve port and is used to control the connection and disconnection between the first valve port and the exhaust port.

6. A multi-connection system control method, characterized in that: Used to control the multi-split system according to any one of claims 1 to 5, the multi-split system control method comprises: determining, among the plurality of indoor heat exchangers, all target indoor heat exchangers having operation requirements and target functional modes of the respective target indoor heat exchangers; According to the target functional mode of each target indoor heat exchanger, the on-off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve, and the third stop valve are controlled.

7. The multi-connection system control method according to claim 6, characterized in that: According to the target functional mode of each target indoor heat exchanger, controlling the on / off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve, and the third stop valve includes: When the target function mode of each target indoor heat exchanger is a cooling function mode, the first valve port and the second valve port are controlled to be connected, the third valve port and the fourth valve port are controlled to be connected, the fifth valve port and the sixth valve port are controlled to be connected, the seventh valve port and the eighth valve port are controlled to be connected, and the first stop valve is controlled to be turned on, and the second stop valve and the third stop valve connected to each target indoor heat exchanger are controlled to remain turned on, and the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain turned off.

8. The multi-connection system control method according to claim 6, characterized in that According to the target functional mode of each target indoor heat exchanger, controlling the on / off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve, and the third stop valve includes: When the target function mode of each target indoor heat exchanger is a heating function mode, and the heat exchange demand of any two target indoor heat exchangers is the same, the first valve port is controlled to be connected to the second valve port, the third valve port is controlled to be connected to the fourth valve port, the fifth valve port is controlled to be connected to the eighth valve port, the sixth valve port is controlled to be connected to the seventh valve port, and the first stop valve is controlled to remain closed, and the second stop valve connected to each target indoor heat exchanger is controlled to remain closed, and the third stop valve is controlled to remain open, and the second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain closed.

9. The multi-connection system control method according to claim 6, characterized in that: According to the target functional mode of each target indoor heat exchanger, controlling the on / off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve, and the third stop valve includes: When the target function mode of each target indoor heat exchanger is a heating function mode, and the heat exchange demand of at least two target indoor heat exchangers is different, the first valve port is controlled to be connected to the fourth valve port, the second valve port is controlled to be connected to the third valve port, the fifth valve port is controlled to be connected to the eighth valve port, the sixth valve port is controlled to be connected to the seventh valve port, the first stop valve is controlled to remain closed, and the second stop valve connected to part of the target indoor heat exchangers is controlled to be turned on and the third stop valve is turned off, and the second stop valve connected to another part of the target indoor heat exchangers is controlled to be turned off and the third stop valve is controlled to be turned on.

10. The multi-connection system control method according to claim 6, characterized in that: According to the target functional mode of each target indoor heat exchanger, controlling the on / off states of the first four-way valve, the second four-way valve, the first stop valve, the second stop valve, and the third stop valve includes: When the target functional mode of some of the target indoor heat exchangers is a cooling functional mode and the target functional mode of another part of the target indoor heat exchangers is a heating functional mode, determining a total heat exchange demand of the multi-split system; When the total heat exchange demand of the multi-split system is heating, the first valve port is controlled to be connected to the second valve port, the third valve port is controlled to be connected to the fourth valve port, the fifth valve port is controlled to be connected to the eighth valve port, the sixth valve port is controlled to be connected to the seventh valve port, and the first stop valve is controlled to be opened. The third stop valve connected to the target indoor heat exchanger for heating is controlled to be opened, and the second stop valve connected to the target indoor heat exchanger for heating is controlled to be closed. The second stop valve connected to the target indoor heat exchanger for cooling is controlled to be opened, and the third stop valve connected to the target indoor heat exchanger for cooling is controlled to be closed. In addition, the second stop valve and the third stop valve connected to the other indoor heat exchangers except the target indoor heat exchanger are controlled to remain closed. When the total heat exchange demand of the multi-split system is cooling or non-stop defrosting, the first valve port is controlled to be connected to the fourth valve port, the second valve port is controlled to be connected to the third valve port, the fifth valve port is controlled to be connected to the sixth valve port, the seventh valve port is controlled to be connected to the eighth valve port, and the first stop valve is controlled to be cut off. The second stop valve connected to the target indoor heat exchanger for heating is controlled to be turned on, and the third stop valve connected to the target indoor heat exchanger for heating is controlled to be turned on, and the second stop valve connected to the target indoor heat exchanger for cooling is controlled to be cut off. The second stop valve and the third stop valve connected to other indoor heat exchangers except the target indoor heat exchanger are controlled to remain cut off.

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