Air conditioner control method

Abstract

The present invention relates to the field of air conditioning technology, and in particular to a control method for an air conditioner. The present application aims to solve the problem that the compressor failure is easily caused when the pressure of the air conditioning system is abnormally high. To this end, the compressor of the air conditioner of the present application is a variable capacity compressor, the outdoor heat exchanger includes a plurality of heat exchange pipe sections, and the outdoor heat exchanger also includes an on-off valve group, which is configured to control the connection between the plurality of heat exchange pipe sections; the control method includes: obtaining the high pressure and low pressure of the air conditioner; calculating a first ratio of the high pressure to the low pressure; comparing the first ratio with a preset threshold; based on the comparison result, selectively adjusting the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group. The present application can adjust the effective system pressure, maintain the high and low pressure ratio of the system within a safe range threshold, and utilize the switching of multiple working modes of the variable capacity compressor in the intelligent coordination process to make the air conditioner run more efficiently and stably.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a control method for an air conditioner. Background Art

[0002] The compressor is the core functional component of the air conditioner, and its operating stability directly determines the operating stability of the air conditioner.

[0003] When the air conditioner is dirty and clogged, the throttling is too small, or the air supply is poor, the system pressure will be abnormally high, which will manifest as high high-pressure pressure, low low-pressure pressure, a larger high-low pressure ratio, and a larger system load. If the compressor torque compensation is insufficient, it will cause the balance ratio to be distorted and excessive vibration will occur, eventually causing the compressor to shut down or be in a stalled state, which will eventually lead to severe wear of the compressor or burnt out of the motor.

[0004] Accordingly, this field requires a new technical solution to solve the above problems. Summary of the Invention

[0005] In order to solve at least one of the above-mentioned problems in the prior art, that is, to solve the problem that compressor failure is easily caused when the pressure of the air-conditioning system is abnormally high, the present application provides a control method for an air conditioner, wherein the air conditioner includes a variable-capacity compressor, an outdoor heat exchanger, a throttling device and an indoor heat exchanger connected by a refrigerant pipeline, the variable-capacity compressor has two compression cylinders, the outdoor heat exchanger includes a plurality of heat exchange pipe sections, and an on-off valve group is further provided in the outdoor heat exchanger, the on-off valve group includes a plurality of on-off valves, and the on-off valve group is configured to control the communication between the plurality of heat exchange pipe sections.

[0006] The control method includes:

[0007] Obtaining the high pressure and low pressure of the air conditioner;

[0008] calculating a first ratio of the high pressure to the low pressure;

[0009] comparing the first ratio with a preset threshold;

[0010] selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result;

[0011] Among them, the working modes of the variable capacity compressor include a dual-cylinder mode and a two-stage mode. In the dual-cylinder mode, the two compression cylinders of the variable capacity compressor compress the refrigerant separately. In the two-stage mode, the two compression cylinders of the variable capacity compressor compress the refrigerant successively.

[0012] In the preferred technical solution of the control method of the above-mentioned air conditioner, the outdoor heat exchanger includes a first heat exchange pipe section, a second heat exchange pipe section and a third heat exchange pipe section connected in sequence, and the outdoor heat exchanger also includes a first branch pipe, a second branch pipe and a third branch pipe, the first end of the first branch pipe is connected to the refrigerant pipe between the variable capacity compressor and the first heat exchange pipe section, the second end of the first branch pipe is connected to the refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section, one end of the second branch pipe is connected to the third branch pipe, the second end of the second branch pipe is connected to an end of the third heat exchange pipe section close to the second heat exchange pipe section, the first end of the third branch pipe is connected to the refrigerant pipe between the first heat exchange pipe section and the second heat exchange pipe section, the second end of the third branch pipe is connected to the refrigerant pipe between the third heat exchange pipe section and the throttling device,

[0013] The on-off valve group includes a first on-off valve, a second on-off valve, a third on-off valve and a fourth on-off valve. The first on-off valve is arranged on the first branch pipe, the second on-off valve is arranged on the refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section and is located between the second end of the first branch pipe and the third heat exchange pipe section, the third on-off valve is arranged on the second branch pipe, and the fourth on-off valve is arranged on the third branch pipe and is located between the first end of the second branch pipe and the second end of the third branch pipe.

[0014] In the preferred technical solution of the above-mentioned air conditioner control method, the opening and closing modes include a first mode, a second mode, a third mode and a fourth mode, wherein:

[0015] The first mode is: the first on-off valve is closed, the second on-off valve is open, the third on-off valve is closed, and the fourth on-off valve is closed;

[0016] The second mode is: the first on-off valve is open, the second on-off valve is closed, the third on-off valve is open, and the fourth on-off valve is closed;

[0017] The third mode is: the first on-off valve is open, the second on-off valve is open, the third on-off valve is open, and the fourth on-off valve is closed;

[0018] The fourth mode is: the first on-off valve is open, the second on-off valve is open, the third on-off valve is open, and the fourth on-off valve is open.

[0019] In the preferred technical solution of the above-mentioned air conditioner control method, the step of "selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result" further includes:

[0020] If the first ratio is greater than the preset threshold, the current working mode and opening and closing mode are switched to the next working mode and opening and closing mode in a preset order.

[0021] In the preferred technical solution of the control method of the above-mentioned air conditioner, the preset order is: the first mode and the two-stage mode, the first mode and the two-cylinder mode, the second mode and the two-stage mode, the second mode and the two-cylinder mode, the third mode and the two-cylinder mode, and the fourth mode and the two-cylinder mode.

[0022] In the preferred technical solution of the above-mentioned air conditioner control method, the step of "selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result" further includes:

[0023] If the first ratio is less than or equal to the preset threshold, the air conditioner is controlled to maintain the current operation state.

[0024] In the preferred technical solution of the above-mentioned air conditioner control method, the control method further includes:

[0025] If the current opening and closing mode of the on-off valve group is the fourth mode, and the first ratio is greater than the preset threshold, the compressor is controlled to stop.

[0026] In the preferred technical solution of the above-mentioned air conditioner control method, before the step of "obtaining the high pressure and low pressure of the air conditioner", the control method further includes:

[0027] Obtaining the outdoor ambient temperature and the operating frequency of the variable capacity compressor;

[0028] determining an operating mode of the variable capacity compressor and an opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency;

[0029] Based on the working mode and the opening and closing mode, the variable capacity compressor and the on-off valve group are controlled to operate respectively.

[0030] In the preferred technical solution of the above-mentioned air conditioner control method, the step of "determining the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes:

[0031] If the outdoor ambient temperature is less than or equal to a first temperature threshold and the operating frequency is less than or equal to a first frequency threshold, determining that the operating mode of the variable capacity compressor is the two-stage mode and the opening and closing mode of the on-off valve group is the first mode;

[0032] If the outdoor ambient temperature is less than or equal to the first temperature threshold and the operating frequency is greater than the first frequency threshold, it is determined that the operating mode of the variable capacity compressor is the two-cylinder mode and the opening and closing mode of the on-off valve group is the first mode.

[0033] In the preferred technical solution of the above-mentioned air conditioner control method, the step of "determining the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes:

[0034] If the outdoor ambient temperature is greater than the first temperature threshold and the operating frequency is less than or equal to a second frequency threshold, determining that the operating mode of the variable capacity compressor is the two-stage mode and the opening and closing mode of the on-off valve group is the second mode;

[0035] If the outdoor ambient temperature is greater than the first temperature threshold and the operating frequency is greater than the second frequency threshold, determining that the operating mode of the variable displacement compressor is the two-cylinder mode and the opening and closing mode of the on-off valve group is the second mode;

[0036] The second frequency threshold is greater than the first frequency threshold.

[0037] The control method of this application automatically detects the system pressure ratio according to different system pressure ratios and load conditions, and adjusts the opening and closing mode of the on-off valve group based on this, which can effectively adjust the system pressure, maintaining the system high and low pressure ratios within a safe range threshold while ensuring the cooling effect, ensuring the normal operation of the air conditioner and improving the operating reliability of the compressor. The configuration of the variable volume compressor can be used to switch between multiple operating modes during the system pressure adjustment process, making the air conditioner operation more efficient and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The present application is described below with reference to the accompanying drawings.

[0039] Figure 1 A system diagram of a first embodiment of the air conditioner of the present application;

[0040] Figure 2 A system diagram of a second embodiment of the air conditioner of the present application;

[0041] Figure 3 This is a flow chart of a first embodiment of the air conditioner control method of the present application;

[0042] Figure 4 A logic diagram of a possible implementation of the air conditioner control method of the present application;

[0043] Figure 5This is a flow chart of a second embodiment of the air conditioner control method of the present application.

[0044] Reference Signs List

[0045] 1. Compressor; 11. First compression cylinder; 12. Second compression cylinder; 13. First port; 14. Second port; 15. Third port; 16. Fourth port; 17. Exhaust port; 2. Second four-way valve; 3. Outdoor heat exchanger; 31. First heat exchange pipe section; 32. Second heat exchange pipe section; 33. Third heat exchange pipe section; 4. Throttling device; 5. Indoor heat exchanger; 6. Refrigerant pipeline; 71. First branch pipe; 72. Second branch pipe; 73. Third branch pipe; 81. First on-off valve; 82. Second on-off valve; 83. Third on-off valve; 84. Fourth on-off valve; 9. First four-way valve; 10. Gas-liquid separator. DETAILED DESCRIPTION

[0046] The preferred embodiments of the present application are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are merely used to explain the technical principles of the present application and are not intended to limit the scope of protection of the present application. For example, in the following embodiments, although the various steps are described in the aforementioned order, it will be understood by those skilled in the art that in order to achieve the effect of the present embodiment, the different steps do not have to be performed in such an order, and they can be performed simultaneously (in parallel) or in a reversed order, and these simple changes are all within the scope of protection of the present application.

[0047] It should be noted that, in the description of this application, the terms "upper" and "lower" and other terms indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation of this application. In addition, the terms "first", "second", "third", and "fourth" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, in the description of this application, "multiple" refers to at least two.

[0048] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to direct connections, indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0049] First refer to Figure 1 , the air conditioner of this application is described.

[0050] like Figure 1 As shown, in order to solve the problem of compressor failure easily caused by abnormally high pressure in the air-conditioning system, the air conditioner of the present application includes a compressor 1, a second four-way valve 2, an outdoor heat exchanger 3, a throttling device 4 and an indoor heat exchanger 5. Among them, the compressor 1, the second four-way valve 2, the outdoor heat exchanger 3, the first throttling device 4 and the indoor heat exchanger 5 are connected in sequence through the refrigerant pipeline 6 to form a refrigerant circulation. Preferably, the indoor heat exchanger 5 has an inner exhaust pipeline and an outer exhaust pipeline, which are arranged in parallel. The first throttling device 4 is an electronic expansion valve. The above-mentioned connection method and the working principle of the air conditioner are conventional technical means in this field and will not be repeated in this application.

[0051] In particular, the outdoor heat exchanger 3 of the present application includes multiple heat exchange pipe sections, and an on-off valve group is also provided in the outdoor heat exchanger 3. The on-off valve group includes multiple on-off valves, and the on-off valve group is configured to control the connection between the multiple heat exchange pipe sections.

[0052] Preferably, the outdoor heat exchanger 3 includes a first heat exchange section 31, a second heat exchange section 32, and a third heat exchange section 33, which are connected in sequence. The first heat exchange section 31 is located in the middle of the outdoor heat exchanger 3, the second heat exchange section 32 is located above the first heat exchange section 31, and the third heat exchange section 33 is located below the first heat exchange section 31. One end of the first heat exchange section 31 is connected to the exhaust port 17 of the compressor 1 via the refrigerant pipeline 6. The other end of the first heat exchange section 31 is connected to one end of the second heat exchange section 32 via the refrigerant pipeline 6. The other end of the second heat exchange section 32 is connected to one end of the third heat exchange section 33 via the refrigerant pipeline 6. The other end of the third heat exchange section 33 is connected to the throttling device 4 via the refrigerant pipeline 6.

[0053] The outdoor heat exchanger 3 further includes a first branch pipe 71, a second branch pipe 72, and a third branch pipe 73. The first end of the first branch pipe 71 is connected to the refrigerant pipeline 6 between the compressor 1 and the first heat exchange pipe section 31, and the second end of the first branch pipe 71 is connected to the refrigerant pipeline 6 between the second heat exchange pipe section 32 and the third heat exchange pipe section 33. The first end of the second branch pipe 72 is connected to the third branch pipe 73, and the second end of the second branch pipe 72 is connected to the end of the third heat exchange pipe section 33 closest to the second heat exchange pipe section 32 (i.e., the end of the third heat exchange pipe section 33 connected to the second heat exchange pipe section 32). The first end of the third branch pipe 73 is connected to the refrigerant pipeline 6 between the first heat exchange pipe section 31 and the second heat exchange pipe section 32, and the second end of the third branch pipe 73 is connected to the refrigerant pipeline 6 between the third heat exchange pipe section 33 and the throttling device 4.

[0054] The on-off valve assembly includes a first on-off valve 81, a second on-off valve 82, a third on-off valve 83, and a fourth on-off valve 84. The first on-off valve 81 is disposed on the first branch pipe 71, the second on-off valve 82 is disposed on the refrigerant pipeline 6 between the second heat exchange pipe section 32 and the third heat exchange pipe section 33, and is located between the second end of the first branch pipe 71 and the third heat exchange pipe section 33. The third on-off valve 83 is disposed on the second branch pipe 72, and the fourth on-off valve 84 is disposed on the third branch pipe 73 and is located between the first end of the second branch pipe 72 and the second end of the third branch pipe 73.

[0055] Under the above-mentioned setting method, by controlling the opening and closing of the first on-off valve 81, the second on-off valve 82, the third on-off valve 83 and the fourth on-off valve 84, different connection forms of the first heat exchange pipe section 31, the second heat exchange pipe section 32 and the third heat exchange pipe section 33 can be achieved, thereby achieving different heat exchange effects of the outdoor heat exchanger 3.

[0056] Next refer to Figure 2 In another preferred embodiment, based on the first embodiment, the compressor 1 is a variable capacity compressor having two compression cylinders. Specifically, a first compression cylinder 11 and a second compression cylinder 12 are disposed within the variable capacity compressor. Four ports and an exhaust port 17 are provided on the housing of the compressor 1. The first port 13 is connected to the air inlet of the first compression cylinder 11, the second port 14 is connected to the air outlet of the first compression cylinder 11, the third port 15 is connected to the air inlet of the second compression cylinder 12, the air outlet of the second compression cylinder 12 is connected to the exhaust port 17, and the fourth port 16 is connected to the exhaust port 17 through the interior of the housing.

[0057] The variable capacity compressor is also equipped with a first four-way valve 9 having four ports a, b, c, and d. The first port a is connected to the fourth port 16, the second port b is connected to the second port 14, and the third port c is connected to the third port 15. A moving part is provided inside the first four-way valve 9. When the first four-way valve 9 is powered on or off, the moving part moves within the first four-way valve 9 to connect or block the different ports.

[0058] The second four-way valve 2 is connected to two gas-liquid separators 10, and the outlets of the two gas-liquid separators 10 are respectively connected to the two compression cylinders of the variable capacity compressor. Among them, the outlet of one gas-liquid separator 10 is directly connected to the first port 13, and the outlet of the other gas-liquid separator 10 is connected to the third port 15 indirectly through the fourth interface d of the first four-way valve 9. One end of the air supply pipeline is connected to the inlet of one of the gas-liquid separators 10. Figure 1 and Figure 2 What is shown in FIG. 1 is connected to the inlet of the gas-liquid separator 10 on the right.

[0059] Under the above setting mode, the working modes of the variable capacity compressor include dual-cylinder mode and dual-stage mode. Figure 2 , the first four-way valve 9 is in two-stage mode when it is powered on. In this mode, the two compression cylinders of the variable capacity compressor compress the refrigerant in succession. Specifically, the first interface a and the fourth interface d of the first four-way valve 9 are separated by a moving part. The refrigerant discharged from the outdoor heat exchanger 3 passes through one of the gas-liquid separators 10 and then enters the first compression cylinder 11 through the first port 13. After being compressed by the first compression cylinder 11, it is discharged from the second port 14. Then, after passing through the second interface b and the third interface c of the first four-way valve 9, it enters the second compression cylinder 12 through the third port 15. After secondary compression by the second compression cylinder 12, it is discharged from the exhaust port 17. In this mode, the variable capacity compressor can achieve a larger compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirements and ensuring the cooling effect and cooling efficiency of the air conditioner.

[0060] In contrast, when the first four-way valve 9 is powered off, it is in a dual-cylinder mode. In this mode, the two compression cylinders of the variable capacity compressor compress the refrigerant separately. Specifically, a portion of the refrigerant discharged from the outdoor heat exchanger 3 passes through one of the gas-liquid separators 10 and enters the first compression cylinder 11 from the first port 13. After being compressed by the first compression cylinder 11, it is discharged from the second port 14. Then, it passes through the second interface b and the first interface a of the first four-way valve 9 and enters the shell and is finally discharged from the exhaust port 17. Another portion of the refrigerant passes through another gas-liquid separator 10 and passes through the fourth interface d and the third interface c of the first four-way valve 9, and then enters the second compression cylinder 12 from the third port 15. After being compressed by the second compression cylinder 12, it is discharged from the exhaust port 17. The variable capacity compressor adopts a dual-cylinder mode, which has a lower frequency at the same exhaust volume. In this way, the high pressure of the air-conditioning system becomes lower, the low pressure becomes higher, and the compression ratio of the compressor 1 is reduced.

[0061] Those skilled in the art will understand that the above-mentioned setting of the air conditioner is only a preferred method, and those skilled in the art can adjust the structure of the above-mentioned air conditioner without deviating from the principles of this application, so that this application is applicable to more specific application scenarios. For example, although the above-mentioned air conditioner is introduced in combination with the second four-way valve 2, this embodiment is not static. In other embodiments, those skilled in the art can also selectively omit the second four-way valve 2 to make the air conditioner a single heating air conditioner. For another example, the specific form of the first throttling device 4 is not limited in this application, and the first throttling device 4 can also be a capillary tube or a thermal expansion valve. For another example, although the above-mentioned outdoor heat exchanger 3 is introduced in combination with the main heat exchange pipe section and the auxiliary heat exchange pipe section, the specific structural form of the outdoor heat exchanger 3 is not static. Those skilled in the art can replace it, such as including only the main heat exchange pipe section and omitting the auxiliary heat exchange pipe section. For example, the number and arrangement of the heat exchange pipe sections of the outdoor heat exchanger 3, the number and connection method of the branch pipes, the number and location of the on-off valves in the on-off valve group, and other aspects of the invention can all be adjusted by those skilled in the art so that the invention is applicable to more specific application scenarios. For example, those skilled in the art can increase or decrease the number, location, and connection method of the heat exchange pipe sections; or increase or decrease the number and connection relationship of the branch pipes; or increase or decrease the number and location of the on-off valves. In short, as long as the connection method of the heat exchange pipe sections can be adjusted by controlling the opening and closing of the on-off valves in the on-off valve group, such changes do not deviate from the principles of the invention. For example, the switching between the dual-cylinder mode and the bipolar mode of the variable displacement compressor can be achieved without using the first four-way valve 9, but by setting up multiple valve groups and controlling the opening and closing of each valve in the valve group. For another example, the specific structure of the variable displacement compressor is not fixed. Under the premise of being able to switch between the dual-cylinder mode and the two-stage mode, those skilled in the art can adjust the structure of the variable displacement compressor, such as changing the number, location, and connection relationship of the ports. For another example, the gas-liquid separator 10 and the like are not necessarily provided, and those skilled in the art can select them according to specific needs.

[0062] Refer to the following Figure 3 , the control method of the air conditioner of this application is introduced.

[0063] like Figure 3 As shown, corresponding to the first preferred embodiment of the air conditioner, the control method of the air conditioner of the present application includes:

[0064] S101, obtaining high pressure and low pressure of the air conditioner. For example, the high pressure can be obtained by a pressure sensor provided at the exhaust port of the compressor, and the low pressure can be obtained by a pressure sensor provided at the intake port of the compressor.

[0065] S103: Calculate a first ratio of the high pressure to the low pressure. For example, after obtaining the high pressure and the low pressure, divide the high pressure by the low pressure to calculate the first ratio between the two.

[0066] S105: Compare the first ratio with a preset threshold. For example, after calculating the first ratio, the high and low pressure ratios of the air conditioning system can be obtained. By comparing the high and low pressure ratios with the preset threshold, the current system pressure ratio can be determined. The pressure ratio can then be used to determine an appropriate opening and closing mode for the on-off valve group. The system pressure ratio can then be adjusted by adjusting the opening and closing mode of the on-off valve group.

[0067] S107: selectively adjust the on / off mode of the on / off valve group based on the comparison result. For example, after determining the on / off mode of the on / off valve group, control each on / off valve in the on / off valve group to be switched on / off according to the on / off mode.

[0068] The control method of the present application automatically detects the system pressure ratio according to different system pressure ratios and load conditions, and adjusts the opening and closing mode of the on-off valve group based on this, so as to effectively adjust the system pressure, maintain the high and low pressure ratios of the system within a safe range threshold while ensuring the cooling effect, ensure the normal operation of the air conditioner, and improve the operating reliability of the compressor.

[0069] The first preferred technical solution of this application is introduced below.

[0070] In one embodiment, the on-off valve group of the present application has an opening and closing mode including a first mode, a second mode, a third mode and a fourth mode.

[0071] In the first mode, the first, third, and fourth on-off valves are closed, and the second on-off valve is open. Thus, during operation, refrigerant is discharged from the compressor and passes through the four-way valve. It then enters the first heat exchange segment from the upper portion of the first heat exchange segment, is discharged from the lower portion of the first heat exchange segment, and enters the second heat exchange segment from the lower portion of the second heat exchange segment. It then exits through the upper portion of the second heat exchange segment and enters the third heat exchange segment from the upper portion of the third heat exchange segment. Finally, it exits through the lower portion of the third heat exchange segment to the throttling device. In other words, the refrigerant passes through the first, second, and third heat exchange segments in sequence.

[0072] In the second mode, the first and third on-off valves are open, while the second and fourth on-off valves are closed. Thus, during operation, the refrigerant discharged from the compressor and passing through the four-way valve is split into two parts: one portion enters the first heat exchange segment through the upper portion of the first heat exchange segment and is discharged from the lower portion of the first heat exchange segment, while the other portion enters the second heat exchange segment through the upper portion of the second heat exchange segment and is discharged from the lower portion of the second heat exchange segment. The refrigerants discharged from the first and second heat exchange segments merge and then enter the third heat exchange segment through the upper portion of the third heat exchange segment, finally being discharged from the lower portion of the third heat exchange segment to the throttling device.

[0073] In the third mode, the first, second, and third on-off valves are open, and the fourth on-off valve is closed. Thus, during operation, the refrigerant discharged from the compressor and passing through the four-way valve is split into two. The first portion of the refrigerant enters the first heat exchange segment through the upper portion of the first heat exchange segment and is discharged from the lower portion of the first heat exchange segment. The second portion of the refrigerant is further split into two, with a small portion entering the second heat exchange segment through the upper portion of the second heat exchange segment and being discharged from the lower portion of the second heat exchange segment, while the majority of the refrigerant directly reaches the third heat exchange segment. The refrigerant discharged from the first and second heat exchange segments merges with the refrigerant reaching the third heat exchange segment, and then both enter the third heat exchange segment through the upper portion of the third heat exchange segment and are finally discharged from the lower portion of the third heat exchange segment to the throttling device.

[0074] In the fourth mode, the first, second, third, and fourth on-off valves are all open. Thus, during operation, after the refrigerant is discharged from the compressor and passes through the four-way valve, it is split into two parts. The first part of the refrigerant enters the first heat exchange section through the upper portion of the first heat exchange section, is discharged from the lower portion of the first heat exchange section, and directly reaches the third branch pipe. The second part of the refrigerant is further split into two parts. A small part of the refrigerant enters the second heat exchange section through the upper portion of the second heat exchange section, is discharged from the lower portion of the second heat exchange section, and directly reaches the third branch pipe, while the majority of the refrigerant directly reaches the third branch pipe. The refrigerant discharged from the first and second heat exchange sections merges with the refrigerant that directly reaches the third branch pipe, and then flows together through the third branch pipe to the throttling device.

[0075] From the principle description of the above-mentioned first mode to the fourth mode, it can be seen that during the switching process from the first mode to the fourth mode, the heat exchange effect of the outdoor heat exchanger decreases, the pressure drop of the corresponding air-conditioning system decreases, and the high-low pressure ratio decreases.

[0076] Of course, the four opening and closing modes in this application are merely preferred, and those skilled in the art can make adjustments based on specific application scenarios, such as adding or deleting opening and closing modes.

[0077] In one embodiment, the step of "selectively adjusting the on / off mode of the on / off valve assembly based on the comparison result" further includes: if the first ratio is less than or equal to a preset threshold, controlling the on / off valve assembly to maintain the current on / off state; and if the first ratio is greater than the preset threshold, switching to the next on / off mode in a preset order based on the current on / off mode. Preferably, the preset order is: first mode, second mode, third mode, and fourth mode.

[0078] For example, the preset threshold value can be any value between 2 and 10. In this application, taking the preset threshold value of 4.3 as an example, after calculating the first ratio of high pressure to low pressure, the difference between the first ratio and the preset threshold value of 4.3 is determined. If the first ratio is ≤4.3, it proves that the high and low pressures of the air conditioner are relatively small, the system load is small, and the operation is stable. At this time, it is only necessary to control the on-off valve group to maintain the current open and closed state. On the contrary, when the first ratio is greater than 4.3, the high and low pressures of the system are relatively large, the system load is large, the operating risk of the compressor is large, and the system pressure ratio needs to be reduced. At this time, the on-off valve group is controlled to switch to the next open and close mode. For example, if the current on-off valve group is in the first mode, the on-off valve group is controlled to switch to the second mode, and then the change in the high and low pressure ratio of the system is continuously detected, for example, at an interval of 30 seconds, the first ratio is obtained and calculated again. If the first ratio is greater than 4.3, the on-off valve group is controlled to switch from the second mode to the third mode... and so on.

[0079] The above control method controls the opening and closing mode of the on-off valve group according to a preset sequence. It can automatically detect the system pressure ratio and control the flow path changes according to the current high and low pressure ratios and load conditions of the air conditioner, thereby realizing real-time adjustment of the system pressure. While ensuring the cooling effect, it maintains the pressure ratio within a safe range threshold, ensures the normal operation of the air conditioner, and improves the reliability of the compressor.

[0080] Of course, the above control method is merely a preferred method and can be adjusted by those skilled in the art. For example, those skilled in the art can adjust the preset sequence, provided that the heat exchange efficiency of the outdoor heat exchanger gradually decreases. For another example, when the first pressure ratio is greater than a preset threshold, those skilled in the art can select the on / off valve group's on / off mode based on a comparison table comparing the first ratio and the on / off valve group's on / off mode. For another example, when the first ratio is less than the preset threshold, the on / off valve group's on / off mode can be adjusted in reverse order of the preset sequence to balance the system's high and low pressure ratios and heat exchange efficiency.

[0081] In one embodiment, the control method further includes: if the current opening and closing mode of the on-off valve group is the fourth mode and the first ratio is greater than a preset threshold, controlling the compressor to stop.

[0082] For example, in the process of controlling the opening and closing mode of the on-off valve group in the above manner, if the on-off valve group has switched to the fourth mode and the first ratio of the system is still greater than the preset threshold at this time, the compressor is controlled to stop at this time to protect the compressor and avoid failure.

[0083] In one embodiment, before the step of "obtaining the high pressure and low pressure of the air conditioner", the control method also includes: obtaining the outdoor ambient temperature and the operating frequency of the compressor; determining the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency; and controlling the action of the on-off valve group based on the opening and closing mode.

[0084] For example, when an air conditioner is turned on, the outdoor ambient temperature is obtained through a temperature sensor, and the operating frequency is obtained through the air conditioner's operating information. Of course, the specific method for obtaining the outdoor ambient temperature and the compressor's operating frequency is not fixed, and those skilled in the art can adjust this, as long as the two parameters can be successfully obtained. After obtaining the outdoor ambient temperature and the operating frequency, the on-off valve group's opening and closing mode is determined based on the range of the two; alternatively, the on-off valve group's opening and closing mode is determined based on the comparison relationship between the two and the on-off valve group. After determining the on-off valve group's opening and closing mode, each on-off valve in the on-off valve group is controlled to switch according to the opening and closing mode.

[0085] By determining the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and operating frequency, various diversion modes of the outdoor heat exchanger can be realized. The optimal diversion mode can be adjusted according to the actual load, and the outdoor heat exchanger can be adjusted during the startup process to achieve optimal performance and energy efficiency.

[0086] In one embodiment, the step of "determining the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes: if the outdoor ambient temperature is less than or equal to the first temperature threshold and the operating frequency is less than or equal to the first frequency threshold, then determining that the opening and closing mode of the on-off valve group is the first mode; if the outdoor ambient temperature is less than or equal to the first temperature threshold and the operating frequency is greater than the first frequency threshold, then determining that the opening and closing mode of the on-off valve group is the second mode.

[0087] Specifically, the first temperature threshold takes 22°C as an example, and the first frequency threshold takes 30Hz as an example. When the outdoor ambient temperature is less than or equal to 22°C, and the operating frequency is less than or equal to 30Hz, the starting load of the air conditioner is relatively small, and the on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger has a long process, a large subcooling section, a fast refrigerant flow rate, a large heat exchange capacity, low air conditioning power, and high energy efficiency. When the outdoor ambient temperature is less than or equal to 22°C, and the operating frequency is greater than 30Hz, the starting load of the air conditioner is relatively large, and the on-off valve group adopts the second mode. In this mode, the process is relatively short, the subcooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low. Among them, the specific principles of the first mode and the second mode have been introduced above and will not be repeated here. The same applies below.

[0088] Of course, the above-mentioned first temperature threshold and first frequency threshold are not unique, and those skilled in the art can adjust them based on specific application scenarios.

[0089] In one embodiment, the step of "determining the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes: if the outdoor ambient temperature is greater than a first temperature threshold and less than or equal to a second temperature threshold, and the operating frequency is less than or equal to the second frequency threshold, then determining that the opening and closing mode of the on-off valve group is the first mode; if the outdoor ambient temperature is greater than the first temperature threshold and less than or equal to the second temperature threshold, and the operating frequency is greater than the second frequency threshold, then determining that the opening and closing mode of the on-off valve group is the second mode; wherein the second frequency threshold is greater than the first frequency threshold.

[0090] Specifically, the second temperature threshold takes 29°C as an example, and the second frequency threshold takes 40Hz as an example. When the outdoor ambient temperature is greater than 22°C and less than or equal to 29°C, and the operating frequency is less than or equal to 40Hz, the starting load of the air conditioner is relatively small within the current temperature range, and the on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger has a long process, a large subcooling section, a fast refrigerant flow rate, a large heat exchange capacity, low air conditioning power, and high energy efficiency. When the outdoor ambient temperature is greater than 22°C and less than or equal to 29°C, and the operating frequency is greater than 40Hz, the starting load of the air conditioner is relatively large within the current temperature range, and the on-off valve group adopts the second mode. In this mode, the process is relatively short, the subcooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low.

[0091] Of course, the above-mentioned second temperature threshold and second frequency threshold are not unique, and those skilled in the art can adjust them based on specific application scenarios.

[0092] In one embodiment, the step of "determining the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes: if the outdoor ambient temperature is greater than the second temperature threshold and the operating frequency is less than or equal to the third frequency threshold, then determining the opening and closing mode of the on-off valve group to be the first mode; if the outdoor ambient temperature is greater than the second temperature threshold and the operating frequency is greater than the third frequency threshold, then determining the opening and closing mode of the on-off valve group to be the second mode; wherein the third frequency threshold is greater than the second frequency threshold.

[0093] Specifically, the second temperature threshold is 29°C, and the third frequency threshold is 50Hz. When the outdoor ambient temperature is greater than 29°C and the operating frequency is less than or equal to 50Hz, the starting load of the air conditioner is relatively small within the current temperature range, and the on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger has a long flow, a large subcooling section, a fast refrigerant flow rate, a large heat exchange capacity, low air conditioning power, and high energy efficiency. When the outdoor ambient temperature is greater than 29°C and the operating frequency is greater than 50Hz, the starting load of the air conditioner is relatively large within the current temperature range, and the on-off valve group adopts the second mode. In this mode, the flow is relatively short, the subcooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low.

[0094] Of course, the third frequency threshold mentioned above is not unique, and those skilled in the art can adjust it based on specific application scenarios.

[0095] The following figure Figure 4 A possible implementation process of the control method of this application is introduced.

[0096] like Figure 4 As shown, one possible implementation process is:

[0097] S201, during the cooling operation, obtain the outdoor ambient temperature Tao and the compressor operating frequency f, and then execute S202.

[0098] S202, determining the opening and closing mode of the on-off valve group according to the interval of the outdoor ambient temperature Tao and the operating frequency f, and then executing S203.

[0099] S203, during operation, obtain the high pressure Pcon and low pressure Peva of the air conditioner, and then execute S204.

[0100] S204, calculate the first ratio K1 = Pcon / Peva, and then execute S205.

[0101] S205, determine whether K1>4.3 is true. If so, execute S206; otherwise, execute S209.

[0102] S206, determine whether the current on-off valve group is in the fourth mode. If yes, execute S208; otherwise, if not, execute S207.

[0103] S207, controlling the on-off valve group to switch to the next on-off mode based on the current on-off mode.

[0104] S208, controlling the compressor to stop.

[0105] S209, controlling the on-off valve group to maintain the current open and close state.

[0106] It should be noted that although the detailed steps of the method of the present application are described in detail above, without departing from the basic principles of the present application, technical personnel in this field can combine, split and change the order of the above steps. The modified technical solution does not change the basic concept of the present application and therefore falls within the scope of protection of the present application.

[0107] Refer to the following Figure 5 , another preferred implementation of the control method of the present application is introduced.

[0108] like Figure 5 As shown, corresponding to the second embodiment of the above-mentioned air conditioner, the control method of the present application includes:

[0109] S301: Obtain the high pressure and low pressure of the air conditioner. For example, the high pressure can be obtained by a pressure sensor provided at the exhaust port of the compressor, and the low pressure can be obtained by a pressure sensor provided at the intake port of the compressor.

[0110] S303: Calculate a first ratio of the high pressure to the low pressure. For example, after obtaining the high pressure and the low pressure, divide the high pressure by the low pressure to calculate the first ratio between the two.

[0111] S305: Compare the first ratio with a preset threshold. For example, after calculating the first ratio, the high and low pressure ratios of the air conditioning system can be obtained. By comparing the high and low pressure ratios with the preset threshold, the current system pressure ratio can be determined. The pressure ratio can then be used to determine an appropriate opening and closing mode for the on-off valve group. The system pressure ratio can then be adjusted by adjusting the opening and closing mode of the on-off valve group.

[0112] S307 selectively adjusts the operating mode of the variable capacity compressor and the on / off mode of the on / off valve assembly based on the comparison result. For example, after determining the operating mode of the variable capacity compressor and the on / off mode of the on / off valve assembly, the variable capacity compressor is controlled to switch modes, and each on / off valve in the on / off valve assembly is controlled to open and close according to the on / off mode.

[0113] The control method of this application automatically detects the system pressure ratio according to different system pressure ratios and load conditions, and adjusts the opening and closing mode of the on-off valve group based on this, which can effectively adjust the system pressure, maintaining the system high and low pressure ratios within a safe range threshold while ensuring the cooling effect, ensuring the normal operation of the air conditioner and improving the operating reliability of the compressor. The configuration of the variable capacity compressor can be used to switch between multiple operating modes during the system pressure adjustment process, making the air conditioner operation more efficient and stable.

[0114] The preferred technical solution of this embodiment is introduced below.

[0115] In one embodiment, the step of "selectively adjusting the operating mode of the variable capacity compressor and the on / off valve group opening and closing mode based on the comparison result" further includes: if the first ratio is greater than a preset threshold, switching to the next operating mode and on / off mode based on the current operating mode and on / off mode in a preset sequence. Preferably, the preset sequence is: first mode and two-stage mode, first mode and two-cylinder mode, second mode and two-stage mode, second mode and two-cylinder mode, third mode and two-cylinder mode, and fourth mode and two-cylinder mode.

[0116] Specifically, the preset threshold value can be any value between 2 and 10. In this application, taking the preset threshold value of 4.3 as an example, after calculating the first ratio of high pressure to low pressure, the difference between the first ratio and the preset threshold value 4.3 is determined. If the first ratio is ≤4.3, it proves that the high and low pressures of the air conditioner are relatively small, the system load is small, and the operation is stable. At this time, it is only necessary to control the on-off valve group to maintain the current open and closed state. On the contrary, when the first ratio is greater than 4.3, the high and low pressures of the system are relatively large, the system load is large, the operating risk of the compressor is large, and the system pressure ratio needs to be reduced. At this time, the variable capacity compressor and the control on-off valve group are switched to the next working mode and open and close mode in sequence. For example, if the current variable capacity compressor is in two-stage mode and the on-off valve group is in the first mode, the control compressor is switched to the two-cylinder mode and the on-off valve group is maintained in the first mode. Then, the system continuously detects changes in the high and low pressure ratio, for example, at intervals of 30 seconds, and obtains and calculates the first ratio again. If the first ratio is greater than 4.3, the variable capacity compressor is controlled to switch to the two-stage mode, and the on-off valve group is switched from the first mode to the second mode... and so on.

[0117] The above control method controls the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group in a preset order. It can automatically detect the system pressure ratio according to the current high and low pressure ratios and load conditions of the air conditioner, and control the compression ratio and flow path changes to achieve real-time adjustment of the system pressure. While ensuring the cooling effect, the pressure ratio is maintained within a safe range threshold, ensuring the normal operation of the air conditioner and improving the reliability of the compressor.

[0118] Of course, the above control method is only a preferred method, and those skilled in the art may adjust it. For example, those skilled in the art may adjust the preset sequence, but the premise is that the heat exchange effect of the outdoor heat exchanger gradually decreases. For another example, those skilled in the art may also select the opening and closing mode of the on-off valve group based on a comparison table between the first ratio and the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group when the first pressure ratio is greater than the preset threshold. For another example, when the first ratio is less than the preset threshold, the opening and closing mode of the on-off valve group may be adjusted in the reverse order of the preset sequence to take into account the high and low pressure ratios of the system and the heat exchange effect.

[0119] In the preferred technical solution of the control method of the air conditioner, the control method further includes: if the current opening and closing mode of the on-off valve group is the fourth mode and the first ratio is greater than a preset threshold, controlling the compressor to stop.

[0120] For example, in the process of controlling the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group in the above manner, if the on-off valve group has switched to the fourth mode (the variable capacity compressor must be in the dual-cylinder mode at this time), and the first ratio of the system is still greater than the preset threshold at this time, the compressor is controlled to stop at this time to protect the compressor and avoid failure.

[0121] In the preferred technical solution of the control method of the above-mentioned air conditioner, before the step of "obtaining the high pressure and low pressure of the air conditioner", the control method also includes: obtaining the outdoor ambient temperature and the operating frequency of the variable capacity compressor; based on the outdoor ambient temperature and the operating frequency, determining the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group; based on the working mode and the opening and closing mode, controlling the operation of the variable capacity compressor and the on-off valve group respectively.

[0122] For example, when the air conditioner is turned on, the outdoor ambient temperature is obtained through the temperature sensor, and the operating frequency is obtained through the operating information of the air conditioner. Of course, the specific method of obtaining the outdoor ambient temperature and the operating frequency of the compressor is not fixed, and those skilled in the art can adjust this, as long as the two parameters can be obtained smoothly. After obtaining the outdoor ambient temperature and the operating frequency, the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group are determined based on the range of the two. Alternatively, the working mode and the opening and closing mode are determined based on the comparison relationship between the two and the variable capacity compressor and the on-off valve group. After determining the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group, the switching mode of the variable capacity compressor is controlled, and each on-off valve in the on-off valve group is controlled to be switched according to the opening and closing mode.

[0123] By determining the on / off valve group's opening and closing modes based on the outdoor ambient temperature and operating frequency, various flow diversion methods can be implemented for the outdoor heat exchanger. The optimal diversion method can be adjusted based on the actual load to achieve optimal performance and energy efficiency. By configuring a variable capacity compressor, multiple operating modes can be switched using the variable capacity compressor, making the air conditioner's operation more efficient and stable.

[0124] In one embodiment, the step of "determining the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes: if the outdoor ambient temperature is less than or equal to a first temperature threshold and the operating frequency is less than or equal to a first frequency threshold, then determining that the working mode of the variable capacity compressor is a two-stage mode, and the opening and closing mode of the on-off valve group is a first mode; if the outdoor ambient temperature is less than or equal to the first temperature threshold and the operating frequency is greater than the first frequency threshold, then determining that the working mode of the variable capacity compressor is a two-cylinder mode, and the opening and closing mode of the on-off valve group is the first mode.

[0125] Specifically, the first temperature threshold is 22°C, and the first frequency threshold is 40Hz. When the outdoor ambient temperature is 22°C or less and the operating frequency is 40Hz or less, the air conditioner's starting load is low. The variable displacement compressor operates in two-stage mode. In this mode, the variable displacement compressor can achieve a higher compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirement and ensuring the air conditioner's cooling effect and efficiency. The on-off valve assembly operates in the first mode. In this mode, the outdoor heat exchanger has a long flow path, a large subcooling section, a fast refrigerant flow rate, a high heat exchange rate, low air conditioning power, and high energy efficiency. When the outdoor ambient temperature is 22°C or less and the operating frequency is greater than 40Hz, the air conditioner's starting load is high. The variable displacement compressor operates in a two-cylinder mode, which lowers the frequency at the same exhaust volume. This reduces the high pressure of the air conditioning system and increases the low pressure, reducing the compressor's compression ratio. The on-off valve assembly operates in the first mode. In this mode, the outdoor temperature and compressor operating frequency are moderate, which, combined with the compressor's two-cylinder mode, results in high efficiency.

[0126] Of course, the above-mentioned first temperature threshold and first frequency threshold are not unique, and those skilled in the art can adjust them based on specific application scenarios.

[0127] In one embodiment, the step of "determining the working mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency" further includes: if the outdoor ambient temperature is greater than a first temperature threshold and the operating frequency is less than or equal to a second frequency threshold, then determining that the working mode of the variable capacity compressor is a two-stage mode, and the opening and closing mode of the on-off valve group is a second mode; if the outdoor ambient temperature is greater than the first temperature threshold and the operating frequency is greater than the second frequency threshold, then determining that the working mode of the variable capacity compressor is a dual-cylinder mode, and the opening and closing mode of the on-off valve group is the second mode; wherein the second frequency threshold is greater than the first frequency threshold.

[0128] Specifically, the first temperature threshold is 22°C, and the second frequency threshold is 60Hz. When the outdoor ambient temperature is greater than 22°C and the operating frequency is 60Hz or less, the air conditioner's starting load is relatively low within the current temperature range. The variable-capacity compressor adopts a two-stage mode. In this mode, it can achieve a higher compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirement and ensuring the air conditioner's cooling effect and efficiency. The on-off valve assembly adopts the second mode. In this mode, the flow path is relatively short, the subcooling section is small, the flow rate is slow, the condensing temperature is low, and the power is low. This combination reduces pipeline pressure drop and improves heat exchange capacity. When the outdoor ambient temperature is greater than 22°C and the operating frequency is greater than 60Hz, the air conditioner's starting load is relatively high within the current temperature range. The variable-capacity compressor adopts a two-cylinder mode, which operates at a lower frequency for the same exhaust volume. This reduces the high pressure of the air conditioning system and increases the low pressure, thereby reducing the compressor's compression ratio. The on-off valve assembly adopts the second mode. In this mode, the flow path is relatively short, the subcooling section is small, the flow rate is slow, the condensing temperature is low, and the power is low. The combination of the two can further reduce the system pressure drop and improve the heat exchange capacity.

[0129] Of course, the above-mentioned first temperature threshold and second frequency threshold are not unique, and those skilled in the art can adjust them based on specific application scenarios.

[0130] Those skilled in the art will appreciate that although some embodiments described herein include certain features included in other embodiments but not other features, combinations of features from different embodiments are intended to be within the scope of this application and to form different embodiments. For example, in the claims of this application, any of the claimed embodiments may be used in any combination.

[0131] Thus far, the technical solutions of the present application have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is readily understood by those skilled in the art that the scope of protection of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present application.

Claims

1. A method for controlling an air conditioner, characterized in that: The air conditioner includes a variable capacity compressor, an outdoor heat exchanger, a throttling device and an indoor heat exchanger connected by a refrigerant pipeline. The variable capacity compressor has two compression cylinders. The outdoor heat exchanger includes a plurality of heat exchange pipe sections. An on-off valve group is also provided in the outdoor heat exchanger. The on-off valve group includes a plurality of on-off valves. The on-off valve group is configured to control the communication between the plurality of heat exchange pipe sections. The control method includes: Obtaining the high pressure and low pressure of the air conditioner; calculating a first ratio of the high pressure to the low pressure; comparing the first ratio with a preset threshold; selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result; The variable capacity compressor has two operating modes: a dual-cylinder mode and a dual-stage mode. In the dual-cylinder mode, the two compression cylinders of the variable capacity compressor compress the refrigerant separately. In the dual-stage mode, the two compression cylinders of the variable capacity compressor compress the refrigerant successively. The outdoor heat exchanger includes a first heat exchange pipe section, a second heat exchange pipe section and a third heat exchange pipe section connected in sequence, and the outdoor heat exchanger also includes a first branch pipe, a second branch pipe and a third branch pipe, the first end of the first branch pipe is connected to the refrigerant pipe between the variable capacity compressor and the first heat exchange pipe section, the second end of the first branch pipe is connected to the refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section, the first end of the second branch pipe is connected to the third branch pipe, the second end of the second branch pipe is connected to an end of the third heat exchange pipe section close to the second heat exchange pipe section, the first end of the third branch pipe is connected to the refrigerant pipe between the first heat exchange pipe section and the second heat exchange pipe section, and the second end of the third branch pipe is connected to the refrigerant pipe between the third heat exchange pipe section and the throttling device. The on-off valve group includes a first on-off valve, a second on-off valve, a third on-off valve and a fourth on-off valve, wherein the first on-off valve is arranged on the first branch pipe, the second on-off valve is arranged on the refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section and is located between the second end of the first branch pipe and the third heat exchange pipe section, the third on-off valve is arranged on the second branch pipe, and the fourth on-off valve is arranged on the third branch pipe and is located between the first end of the second branch pipe and the second end of the third branch pipe; The opening and closing modes include a first mode, a second mode, a third mode and a fourth mode, wherein: The first mode is: the first on-off valve is closed, the second on-off valve is open, the third on-off valve is closed, and the fourth on-off valve is closed; The second mode is: the first on-off valve is open, the second on-off valve is closed, the third on-off valve is open, and the fourth on-off valve is closed; The third mode is: the first on-off valve is open, the second on-off valve is open, the third on-off valve is open, and the fourth on-off valve is closed; The fourth mode is: the first on-off valve is open, the second on-off valve is open, the third on-off valve is open, and the fourth on-off valve is open; Before the step of "obtaining the high pressure and low pressure of the air conditioner", the control method further includes: Obtaining the outdoor ambient temperature and the operating frequency of the variable capacity compressor; determining an operating mode of the variable capacity compressor and an opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency; Based on the working mode and the opening and closing mode, the variable capacity compressor and the on-off valve group are controlled to operate respectively.

2. The air conditioner control method according to claim 1, characterized in that: The step of “selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result” further includes: If the first ratio is greater than the preset threshold, the current working mode and opening and closing mode are switched to the next working mode and opening and closing mode in a preset order.

3. The air conditioner control method according to claim 2, characterized in that: The preset order is: the first mode and the two-stage mode, the first mode and the two-cylinder mode, the second mode and the two-stage mode, the second mode and the two-cylinder mode, the third mode and the two-cylinder mode, and the fourth mode and the two-cylinder mode.

4. The air conditioner control method according to claim 1, wherein: The step of “selectively adjusting the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the comparison result” further includes: If the first ratio is less than or equal to the preset threshold, the air conditioner is controlled to maintain the current operation state.

5. The air conditioner control method according to claim 3, characterized in that: The control method further includes: If the current opening and closing mode of the on-off valve group is the fourth mode, and the first ratio is greater than the preset threshold, the compressor is controlled to stop.

6. The air conditioner control method according to claim 1, characterized in that: The step of “determining the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency” further includes: If the outdoor ambient temperature is less than or equal to a first temperature threshold and the operating frequency is less than or equal to a first frequency threshold, determining that the operating mode of the variable capacity compressor is the two-stage mode and the opening and closing mode of the on-off valve group is the first mode; If the outdoor ambient temperature is less than or equal to the first temperature threshold and the operating frequency is greater than the first frequency threshold, it is determined that the operating mode of the variable capacity compressor is the two-cylinder mode and the opening and closing mode of the on-off valve group is the first mode.

7. The air conditioner control method according to claim 6, characterized in that: The step of “determining the operating mode of the variable capacity compressor and the opening and closing mode of the on-off valve group based on the outdoor ambient temperature and the operating frequency” further includes: If the outdoor ambient temperature is greater than the first temperature threshold and the operating frequency is less than or equal to a second frequency threshold, determining that the operating mode of the variable capacity compressor is the two-stage mode and the opening and closing mode of the on-off valve group is the second mode; If the outdoor ambient temperature is greater than the first temperature threshold and the operating frequency is greater than the second frequency threshold, determining that the operating mode of the variable displacement compressor is the two-cylinder mode and the opening and closing mode of the on-off valve group is the second mode; The second frequency threshold is greater than the first frequency threshold.

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