Control method of air conditioner

Abstract

The present application relates to the air conditioning technical field, specifically to a kind of control method of air conditioner.The present application aims to solve the problem that air conditioning system pressure is abnormally high and easily leads to compressor failure.To this end, the outdoor heat exchanger of the air conditioner of the present application includes multiple heat exchange pipe sections, and the outdoor heat exchanger further includes a on-off valve group, which is configured to control the communication form between the multiple heat exchange pipe sections.The control method includes: obtaining the high pressure and low pressure of the air conditioner;calculating the first ratio of the high pressure and low pressure;comparing the size of the first ratio and the preset threshold;based on the comparison result, selectively adjusting the opening and closing mode of the on-off valve group.The present application automatically detects the system pressure ratio and adjusts the opening and closing mode of the on-off valve group based on it under different system pressure ratio and load conditions, which can effectively adjust the system pressure, maintain the system high-low pressure ratio within a safe range threshold, ensure the normal operation of the air conditioner and improve the operation reliability of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioners, in particular to a control method of an air conditioner. BACKGROUND

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

[0003] When the air conditioner has dirty blockage, small throttage or poor air supply, etc., the system pressure will be abnormally high, which is manifested as high system high pressure, low system low pressure, large high-low pressure ratio, large system load, and insufficient compressor torque compensation, which will lead to distorted balance ratio and large vibration, and eventually cause the compressor to stop or be in a locked state, and eventually cause the compressor to wear seriously or burn the motor.

[0004] Correspondingly, there is a need in the art for a new technical solution to solve the above problems. SUMMARY

[0005] In order to solve at least one of the above problems in the prior art, i.e. to solve the problem that the air conditioning system pressure is abnormally high and easily causes compressor failure, the present application provides a control method of an air conditioner, the air conditioner comprising a compressor, an outdoor heat exchanger, a throttage device and an indoor heat exchanger connected by a refrigerant pipeline, the outdoor heat exchanger comprising a plurality of heat exchanger pipe sections, a on-off valve group being further provided in the outdoor heat exchanger, the on-off valve group comprising a plurality of on-off valves, the on-off valve group being configured to control the communication form between the plurality of heat exchanger pipe sections,

[0006] The control method comprises:

[0007] obtaining the high pressure and the 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 value;

[0010] based on the comparison result, selectively adjusting the opening and closing mode of the on-off valve group.

[0011] In the preferred technical scheme of the control method of the air conditioner, the outdoor heat exchanger comprises a first heat exchange pipe section, a second heat exchange pipe section and a third heat exchange pipe section connected in sequence, the outdoor heat exchanger further comprises a first branch pipe, a second branch pipe and a third branch pipe, a first end of the first branch pipe is communicated with a refrigerant pipe between the compressor and the first heat exchange pipe section, a second end of the first branch pipe is communicated with a refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section, one end of the second branch pipe is communicated with the third branch pipe, a second end of the second branch pipe is communicated with one end of the third heat exchange pipe section close to the second heat exchange pipe section, a first end of the third branch pipe is communicated with a refrigerant pipe between the first heat exchange pipe section and the second heat exchange pipe section, and a second end of the third branch pipe is communicated with a refrigerant pipe between the third heat exchange pipe section and the throttling device,

[0012] The on-off valve group comprises 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 in the first branch pipe, the second on-off valve is arranged in a refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section and located between the second end of the first branch pipe and the third heat exchange pipe section, the third on-off valve is arranged in the second branch pipe, and the fourth on-off valve is arranged in the third branch pipe and located between the first end of the second branch pipe and the second end of the third branch pipe.

[0013] In the preferred technical scheme of the control method of the air conditioner, the on-off mode comprises a first mode, a second mode, a third mode and a fourth mode, wherein:

[0014] The first mode is that the first on-off valve is closed, the second on-off valve is opened, the third on-off valve is closed and the fourth on-off valve is closed;

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

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

[0017] The fourth mode is that the first on-off valve is opened, the second on-off valve is opened, the third on-off valve is opened and the fourth on-off valve is opened.

[0018] In the preferred technical scheme of the control method of the air conditioner, the step of "selectively adjusting the on-off mode of the on-off valve group based on the comparison result" further comprises:

[0019] If the first ratio is greater than the preset threshold value, the next on-off mode is switched in a preset order on the basis of the current on-off mode.

[0020] In the preferred technical scheme of the control method of the air conditioner, the preset sequence is: the first mode, the second mode, the third mode and the fourth mode.

[0021] In the preferred technical scheme of the control method of the air conditioner, the control method further comprises:

[0022] 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 value, the compressor is controlled to stop.

[0023] In the preferred technical scheme of the control method of the air conditioner, before the step of obtaining the high-pressure pressure and the low-pressure pressure of the air conditioner, the control method further comprises:

[0024] Obtaining the outdoor environment temperature and the operating frequency of the compressor;

[0025] Determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency;

[0026] Controlling the on-off valve group to act based on the opening and closing mode.

[0027] In the preferred technical scheme of the control method of the air conditioner, the step of determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency further comprises:

[0028] If the outdoor environment temperature is less than or equal to a first temperature threshold value, and the operating frequency is less than or equal to a first frequency threshold value, it is determined that the opening and closing mode of the on-off valve group is the first mode;

[0029] If the outdoor environment temperature is less than or equal to the first temperature threshold value, and the operating frequency is greater than the first frequency threshold value, it is determined that the opening and closing mode of the on-off valve group is the second mode.

[0030] In the preferred technical scheme of the control method of the air conditioner, the step of determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency further comprises:

[0031] If the outdoor environment temperature is greater than the first temperature threshold value and less than or equal to a second temperature threshold value, and the operating frequency is less than or equal to a second frequency threshold value, it is determined that the opening and closing mode of the on-off valve group is the first mode;

[0032] If the outdoor environment temperature is greater than the first temperature threshold value and less than or equal to the second temperature threshold value, and the operating frequency is greater than the second frequency threshold value, it is determined that the opening and closing mode of the on-off valve group is the second mode.

[0033] wherein the second frequency threshold is greater than the first frequency threshold.

[0034] In the preferred technical scheme of the control method of the air conditioner, 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 comprises:

[0035] if the outdoor ambient temperature is greater than the second temperature threshold and the operating frequency is less than or equal to a third frequency threshold, determining the opening and closing mode of the on-off valve group as the first mode;

[0036] if the outdoor ambient temperature is greater than the second temperature threshold and the operating frequency is greater than the third frequency threshold, determining the opening and closing mode of the on-off valve group as the second mode;

[0037] wherein the third frequency threshold is greater than the second frequency threshold.

[0038] The control method of the present application can effectively adjust the system pressure by automatically detecting the system pressure ratio and adjusting the opening and closing mode of the on-off valve group based on the system pressure ratio under different pressure ratios and loads, maintaining the high and low pressure ratios of the system within a safe threshold range under the premise of ensuring the refrigeration effect, ensuring the normal operation of the air conditioner, and improving the operation reliability of the compressor. BRIEF DESCRIPTION OF DRAWINGS

[0039] The present application will be described below with reference to the accompanying drawings. In the drawings:

[0040] Figure 1 a system diagram of a first embodiment of the air conditioner of the present application;

[0041] Figure 2 a system diagram of a second embodiment of the air conditioner of the present application;

[0042] Figure 3 a flowchart of a first embodiment of the control method of the air conditioner of the present application;

[0043] Figure 4 a logic diagram of a possible embodiment of the control method of the air conditioner of the present application;

[0044] Figure 5 a flowchart of a second embodiment of the control method of the air conditioner of the present application.

[0045] List of reference signs

[0046] 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 tube section; 32 second heat exchange tube section; 33 third heat exchange tube section; 4 throttling device; 5 indoor heat exchanger; 6 refrigerant line; 71 first branch; 72 second branch; 73 third branch; 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

[0047] The preferred embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood that the embodiments are only used to explain the technical principles of the present application, and are not intended to limit the protection scope of the present application. For example, although the steps in the following embodiments are described in the above order, it should be understood by those skilled in the art that, in order to achieve the effects of the embodiments, the steps do not have to be executed in such an order, and they can be executed simultaneously (in parallel) or in a reversed order, and these simple changes are within the protection scope of the present application.

[0048] It should be noted that, in the description of the present application, the terms indicating the direction or position relationship of "upper", "lower", etc. are based on the direction or position relationship shown in the drawings, which is only 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, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", "fourth" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. In addition, in the description of the present application, "a plurality of" means at least two.

[0049] In addition, it should also be noted that, in the description of the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication inside two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to the specific circumstances.

[0050] Firstly, referring to Figure 1 The air conditioner of the present application is described.

[0051] As Figure 1As shown, in order to solve the problem that the compressor is prone to failure when the pressure of the air conditioning system is abnormally high, the air conditioner of the present application comprises 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 sequentially communicated through the refrigerant pipeline 6 to form a refrigerant circulation. Preferably, the indoor heat exchanger 5 has an inner discharge pipeline and an outer discharge pipeline, which are connected in parallel. The first throttling device 4 is an electronic expansion valve. The above connection mode and the working principle of the air conditioner are conventional technical means in the art, and will not be described here.

[0052] In particular, the outdoor heat exchanger 3 of the present application comprises a plurality of heat exchange pipe sections, and a on-off valve group is further arranged in the outdoor heat exchanger 3. The on-off valve group comprises a plurality of on-off valves and is arranged to be capable of controlling the communication form between the plurality of heat exchange pipe sections.

[0053] Preferably, the outdoor heat exchanger 3 comprises a first heat exchange pipe section 31, a second heat exchange pipe section 32 and a third heat exchange pipe section 33 connected in sequence. The first heat exchange pipe section 31 is located in the middle of the outdoor heat exchanger 3, the second heat exchange pipe section 32 is located above the first heat exchange pipe section 31, and the third heat exchange pipe section 33 is located below the first heat exchange pipe section 31. One end of the first heat exchange pipe section 31 is communicated with the exhaust port 17 of the compressor 1 through the refrigerant pipeline 6, the other end of the first heat exchange pipe section 31 is communicated with one end of the second heat exchange pipe section 32 through the refrigerant pipeline 6, the other end of the second heat exchange pipe section 32 is communicated with one end of the third heat exchange pipe section 33 through the refrigerant pipeline 6, and the other end of the third heat exchange pipe section 33 is communicated with the throttling device 4 through the refrigerant pipeline 6.

[0054] The outdoor heat exchanger 3 further comprises a first branch pipe 71, a second branch pipe 72 and a third branch pipe 73. Among them, the first end of the first branch pipe 71 is communicated with 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 communicated with 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 communicated with the third branch pipe 73, the second end of the second branch pipe 72 is communicated with one end of the third heat exchange pipe section 33 close to the second heat exchange pipe section 32 (i.e. the end of the third heat exchange pipe section 33 communicated with the second heat exchange pipe section 32), the first end of the third branch pipe 73 is communicated with 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 communicated with the refrigerant pipeline 6 between the third heat exchange pipe section 33 and the throttling device 4.

[0055] The on-off valve group 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. Among them, the first on-off valve 81 is arranged on the first branch pipe 71, the second on-off valve 82 is arranged 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 arranged on the second branch pipe 72, and the fourth on-off valve 84 is arranged on the third branch pipe 73 and located between the first end of the second branch pipe 72 and the second end of the third branch pipe 73.

[0056] In the above arrangement, 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 communication 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 realized, so as to realize different heat exchange effects of the outdoor heat exchanger 3.

[0057] Next, referring to Figure 2 , in another preferred embodiment, on the basis of the first embodiment, the compressor 1 is a variable displacement compressor, and the variable displacement compressor has two compression cylinders. Specifically, the variable displacement compressor is internally provided with a first compression cylinder 11 and a second compression cylinder 12, and four ports and an exhaust port 17 are opened on the compressor 1 shell, wherein the first port 13 is in communication with the gas inlet of the first compression cylinder 11, the second port 14 is in communication with the gas outlet of the first compression cylinder 11, the third port 15 is in communication with the gas inlet of the second compression cylinder 12, the gas outlet of the second compression cylinder 12 is in communication with the exhaust port 17, and the fourth port 16 is in communication with the exhaust port 17 through the inside of the shell.

[0058] The variable displacement compressor is also provided with a first four-way valve 9, and the first four-way valve 9 has four interfaces a, b, c and d, wherein the first interface a is in communication with the fourth port 16, the second interface b is in communication with the second port 14, and the third interface c is in communication with the third port 15. The first four-way valve 9 is internally provided with a moving part, which moves in the first four-way valve 9 when the first four-way valve 9 is powered on or powered off, to realize the communication and blockage between different interfaces.

[0059] The second four-way valve 2 is in communication with two gas-liquid separators 10, and the outlets of the two gas-liquid separators 10 are respectively in communication with the two compression cylinders of the variable displacement compressor. Among them, the outlet of one gas-liquid separator 10 is directly in communication with the first port 13, and the outlet of the other gas-liquid separator 10 is in communication through the fourth interface d of the first four-way valve 9, indirectly realizing communication with the third port 15. One end of the gas supplement pipeline is in communication with the inlet of one of the gas-liquid separators 10, Figure 1 and Figure 2 The other end is in communication with the inlet of the other gas-liquid separator 10.

[0060] In the above setting mode, the working modes of the variable displacement compressor include a double-cylinder mode and a double-stage mode. Referring to Figure 2 , the first four-way valve 9 is powered in the double-stage mode. In this mode, the two compression cylinders of the variable displacement compressor compress the refrigerant in turn. Specifically, the first interface a and the fourth interface d of the first four-way valve 9 are separated by the moving piece, and the refrigerant discharged from the outdoor heat exchanger 3 enters the first compression cylinder 11 through one of the gas-liquid separators 10 and the first port 13, is compressed by the first compression cylinder 11, and is discharged from the second port 14, then passes through the second interface b and the third interface c of the first four-way valve 9, enters the second compression cylinder 12 through the third port 15, and is discharged from the exhaust port 17 after being compressed twice by the second compression cylinder 12. In this mode, the variable displacement compressor can achieve a larger compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirement and ensuring the refrigeration effect and efficiency of the air conditioner.

[0061] On the contrary, the first four-way valve 9 is powered in the double-cylinder mode, in which the two compression cylinders of the variable displacement compressor compress the refrigerant separately. Specifically, part of the refrigerant discharged from the outdoor heat exchanger 3 enters the first compression cylinder 11 from the first port 13 after passing through one of the gas-liquid separators 10, is compressed by the first compression cylinder 11, and is discharged from the second port 14, then enters the housing through the second interface b and the first interface a of the first four-way valve 9, and is finally discharged from the exhaust port 17. Another part of the refrigerant passes through the other gas-liquid separator 10, then 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, and is discharged from the exhaust port 17 after being compressed by the second compression cylinder 12. The variable displacement compressor adopts the double-cylinder mode, and at the same exhaust volume, the frequency is lower, so that the high pressure of the air conditioning system is lowered, the low pressure is increased, and the compression ratio of the compressor 1 is reduced.

[0062] 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.

[0063] Refer to the following Figure 3 , the control method of the air conditioner of this application is introduced.

[0064] 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:

[0065] 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.

[0066] S103, calculate a first ratio of the high pressure and the low pressure. For example, after obtaining the high pressure and the low pressure, the first ratio of the high pressure and the low pressure is calculated by dividing the high pressure by the low pressure.

[0067] S105, compare the first ratio with a preset threshold. For example, after calculating the first ratio, the high-low pressure ratio of the air conditioning system can be obtained, and the current system pressure ratio can be determined by comparing the high-low pressure ratio with the preset threshold, so as to determine the opening and closing mode of the on-off valve group suitable for the current situation by the pressure ratio, and to adjust the opening and closing mode of the on-off valve group to adjust the system pressure ratio.

[0068] S107, selectively adjust the opening and closing mode of the on-off valve group based on the comparison result. For example, after determining the opening and closing mode of the on-off valve group, each on-off valve in the on-off valve group is controlled to be switched according to the opening and closing mode.

[0069] The control method of the present application can automatically detect the system pressure ratio for different system pressure ratios and load conditions, and adjust the opening and closing mode of the on-off valve group based on the same, so as to effectively adjust the system pressure, maintain the system high-low pressure ratio within a safe range threshold under the premise of ensuring the refrigeration effect, ensure the normal operation of the air conditioner, and improve the operation reliability of the compressor.

[0070] The first preferred technical solution of the present application will be introduced below.

[0071] In one embodiment, the opening and closing mode of the on-off valve group of the present application includes a first mode, a second mode, a third mode and a fourth mode. Wherein:

[0072] In the first mode, the first on-off valve, the third on-off valve and the fourth on-off valve are closed, and the second on-off valve is opened. In this way, during operation, the refrigerant is discharged from the compressor, passes through the four-way valve, enters the first heat exchange pipe section from the upper part of the first heat exchange pipe section, is discharged from the lower part of the first heat exchange pipe section and enters the second heat exchange pipe section from the lower part of the second heat exchange pipe section, is discharged from the upper part of the second heat exchange pipe section and enters the third heat exchange pipe section from the upper part of the third heat exchange pipe section, and is finally discharged from the lower part of the third heat exchange pipe section to the throttling device. That is, the refrigerant passes through the first heat exchange pipe section, the second heat exchange pipe section and the third heat exchange pipe section in sequence.

[0073] In the second mode, the first and third on-off valves are open, and the second and fourth on-off valves are closed. In this way, during operation, the refrigerant discharged from the compressor is divided into two parts after passing through the four-way valve, one part enters the first heat exchange pipe section through the upper part of the first heat exchange pipe section, and is discharged from the lower part of the first heat exchange pipe section, and the other part enters the second heat exchange pipe section through the upper part of the second heat exchange pipe section, and is discharged from the lower part of the second heat exchange pipe section. The refrigerant discharged from the first and second heat exchange pipe sections is combined and enters the third heat exchange pipe section through the upper part of the third heat exchange pipe section, and is finally discharged from the lower part of the third heat exchange pipe section to the throttling device.

[0074] In the third mode, the first, second and third on-off valves are open, and the fourth on-off valve is closed. In this way, during operation, the refrigerant discharged from the compressor is divided into two parts after passing through the four-way valve, one part enters the first heat exchange pipe section through the upper part of the first heat exchange pipe section, and is discharged from the lower part of the first heat exchange pipe section, and the other part is again divided into two parts, one part enters the second heat exchange pipe section through the upper part of the second heat exchange pipe section, and is discharged from the lower part of the second heat exchange pipe section, and the other part directly reaches the third heat exchange pipe section. The refrigerant discharged from the first and second heat exchange pipe sections is combined and enters the third heat exchange pipe section through the upper part of the third heat exchange pipe section, and is finally discharged from the lower part of the third heat exchange pipe section to the throttling device.

[0075] In the fourth mode, the first, second, third and fourth on-off valves are open. In this way, during operation, the refrigerant discharged from the compressor is divided into two parts after passing through the four-way valve, one part enters the first heat exchange pipe section through the upper part of the first heat exchange pipe section, and is discharged from the lower part of the first heat exchange pipe section to directly reach the third branch pipe, and the other part is again divided into two parts, one part enters the second heat exchange pipe section through the upper part of the second heat exchange pipe section, and is discharged from the lower part of the second heat exchange pipe section to directly reach the third branch pipe, and the other part directly reaches the third branch pipe. The refrigerant discharged from the first and second heat exchange pipe sections is combined and flows to the throttling device through the third branch pipe.

[0076] From the above description of the principles of the first to fourth modes, 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, and the pressure drop of the air conditioning system and the high-low pressure ratio decrease.

[0077] Of course, the on-off modes in the present application include four preferred modes, and those skilled in the art can adjust them based on specific application scenarios. For example, increase or delete the on-off modes.

[0078] In one embodiment, the step of "selectively adjusting the opening and closing mode of the on-off valve group based on the comparison result" further comprises: if the first ratio is less than or equal to a preset threshold, controlling the on-off valve group to maintain the current opening and closing state; and if the first ratio is greater than the preset threshold, switching to the next opening and closing mode in a preset order based on the current opening and closing mode. Preferably, the preset order is: the first mode, the second mode, the third mode, and the fourth mode.

[0079] For example, the preset threshold can be any value in the range of 2-10. In this application, the preset threshold is taken as 4.3. After calculating the first ratio of the high pressure to the low pressure, the difference between the first ratio and the preset threshold 4.3 is determined. If the first ratio is less than or equal to 4.3, it means that the high-low pressure ratio of the air conditioner is small, the system load is small, and the operation is stable, so the on-off valve group only needs to be controlled to maintain the current opening and closing state. Conversely, if the first ratio is greater than 4.3, the high-low pressure ratio of the system is large, the system load is large, and the operation risk of the compressor is large, so the system pressure ratio needs to be reduced. At this time, the on-off valve group is controlled to switch to the next opening and closing mode. For example, if the on-off valve group is currently in the first mode, the on-off valve group is controlled to switch to the second mode, and then the change in the system high-low pressure ratio is continuously detected, for example, at an interval of 30 seconds, the first ratio is calculated again, and 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.

[0080] The above control method can automatically detect the system pressure ratio and control the flow path change by controlling the opening and closing mode of the on-off valve group in a preset order, so as to realize real-time adjustment of the system pressure ratio, ensure that the pressure ratio is within a safe range threshold under the condition of maintaining the refrigeration effect, ensure normal operation of the air conditioner, and improve the reliability of the compressor.

[0081] Of course, the above control method is only preferred, and those skilled in the art can also make adjustments. For example, those skilled in the art can adjust the preset order, but the precondition is to gradually reduce the heat exchange effect of the outdoor heat exchanger. For another example, those skilled in the art can also select the opening and closing mode of the on-off valve group according to a comparison table between the first ratio 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 can also be adjusted in the reverse order of the preset order to take into account the high-low pressure ratio of the system and the heat exchange effect.

[0082] In one embodiment, the control method further comprises: 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, controlling the compressor to stop.

[0083] For example, during 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 been switched to the fourth mode and the first ratio of the system is still greater than the preset threshold value at this time, the compressor is controlled to stop at this time to protect the compressor and avoid malfunction.

[0084] In an embodiment, before the step of "obtaining the high-pressure pressure and the low-pressure pressure of the air conditioner", the control method further comprises: obtaining an outdoor environment temperature and a running frequency of the compressor; determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the running frequency; and controlling the on-off valve group to act based on the opening and closing mode.

[0085] For example, when the air conditioner is started, the outdoor environment temperature is obtained through a temperature sensor, and the running frequency is obtained through the running information of the air conditioner. Of course, the specific obtaining method of the outdoor environment temperature and the running frequency of the compressor is not fixed, and those skilled in the art can adjust it as long as the two parameters can be obtained smoothly. After obtaining the outdoor environment temperature and the running frequency, the opening and closing mode of the on-off valve group is determined based on the range in which the two parameters are located; or the opening and closing mode of the on-off valve group is determined based on the comparison relationship between the two parameters and the on-off valve group. After determining the opening and closing mode of the on-off valve group, each on-off valve in the on-off valve group is controlled to open and close according to the opening and closing mode.

[0086] By determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the running frequency, various shunt modes of the outdoor heat exchanger can be realized, the optimal shunt mode can be adjusted according to the actual load, the adjustment of the outdoor heat exchanger during the starting process can be realized, and the performance and energy efficiency are optimal.

[0087] In an embodiment, the step of "determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the running frequency" further comprises: if the outdoor environment temperature is less than or equal to a first temperature threshold value and the running frequency is less than or equal to a first frequency threshold value, determining the opening and closing mode of the on-off valve group as the first mode; and if the outdoor environment temperature is less than or equal to the first temperature threshold value and the running frequency is greater than the first frequency threshold value, determining the opening and closing mode of the on-off valve group as the second mode.

[0088] Specifically, the first temperature threshold is taken as 22℃, and the first frequency threshold is taken as 30Hz. When the outdoor ambient temperature is less than or equal to 22℃, and the operating frequency is less than or equal to 30Hz, the startup load of the air conditioner is small at this time, and the on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger has a long flow process, a large supercooling section, a fast refrigerant flow rate, a large heat exchange capacity, a low air conditioner power, and a high energy efficiency. When the outdoor ambient temperature is less than or equal to 22℃, and the operating frequency is greater than 30Hz, the startup load of the air conditioner is relatively large, and the on-off valve group adopts the second mode. In this mode, the flow process is relatively short, the supercooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low. The specific principles of the first mode and the second mode have been described above, and will not be described here again.

[0089] Of course, the first temperature threshold and the first frequency threshold described above are not unique, and a person skilled in the art can adjust them based on specific application scenarios.

[0090] In an implementation, 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 first temperature threshold and less than or equal to a second temperature threshold, and the operating frequency is less than or equal to a second frequency threshold, 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, determining that the opening and closing mode of the on-off valve group is the second mode; and wherein the second frequency threshold is greater than the first frequency threshold.

[0091] Specifically, the second temperature threshold is taken as 29℃, and the second frequency threshold is taken as 40Hz. When the outdoor ambient temperature is greater than 22℃ and less than or equal to 29℃, and the operating frequency is less than or equal to 40Hz, the startup load of the air conditioner is small in the current temperature range at this time, and the on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger has a long flow process, a large supercooling section, a fast refrigerant flow rate, a large heat exchange capacity, a low air conditioner power, and a high energy efficiency. When the outdoor ambient temperature is greater than 22℃ and less than or equal to 29℃, and the operating frequency is greater than 40Hz, the startup load of the air conditioner is large in the current temperature range, and the on-off valve group adopts the second mode. In this mode, the flow process is relatively short, the supercooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low.

[0092] Of course, the second temperature threshold and the second frequency threshold described above are not unique, and a person skilled in the art can adjust them based on specific application scenarios.

[0093] In one implementation, 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 comprises: 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, determining the opening and closing mode of the on-off valve group as 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, determining the opening and closing mode of the on-off valve group as the second mode; wherein the third frequency threshold is greater than the second frequency threshold.

[0094] Specifically, the second temperature threshold is taken as 29℃, and the third frequency threshold is taken as 50Hz. When the outdoor ambient temperature is greater than 29℃ and the operating frequency is less than or equal to 50Hz, the startup load of the air conditioner is small in 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 process, a large supercooling section, a fast refrigerant flow rate, a large heat exchange amount, a low air conditioner power, and a high energy efficiency. When the outdoor ambient temperature is greater than 29℃ and the operating frequency is greater than 50Hz, the startup load of the air conditioner is large in the current temperature range, and the on-off valve group adopts the second mode. In this mode, the flow process is relatively short, the supercooling section is small, the flow rate is slow, the heat exchange is sufficient, the condensing temperature is low, and the power is low.

[0095] Of course, the third frequency threshold described above is not unique, and those skilled in the art can adjust it based on specific application scenarios.

[0096] The following describes a possible implementation process of the control method of the application with reference to the accompanying drawings. Figure 4 The following describes a possible implementation process of the control method of the application with reference to the accompanying drawings.

[0097] As shown in FIG. 1, in one possible implementation process, the following steps are performed. Figure 4

[0098] S201, in a startup refrigeration operation process, the outdoor ambient temperature Tao and the operating frequency f of the compressor are obtained, and then S202 is performed.

[0099] S202, the opening and closing mode of the on-off valve group is determined according to the interval of the outdoor ambient temperature Tao and the operating frequency f, and then S203 is performed.

[0100] S203, in the operation process, the high-pressure pressure Pcon and the low-pressure pressure Peva of the air conditioner are obtained, and then S204 is performed.

[0101] S204, the first ratio K1 = Pcon / Peva is calculated, and then S205 is performed.

[0102] S205, is K1>4.3 true? If true, S206 is performed, otherwise if not true, S209 is performed.

[0103] ​S206, judging whether the current on-off valve group is in the fourth mode? If yes, S208 is executed, otherwise, S207 is executed.

[0104] S207, controlling the on-off valve group to switch to the next opening and closing mode based on the current opening and closing mode.

[0105] S208, controlling the compressor to stop.

[0106] S209, controlling the on-off valve group to maintain the current opening and closing state.

[0107] It should be noted that although the detailed steps of the method of the present application are described in detail above, the skilled in the art can combine, split and change the order of the above steps without deviating from the basic principles of the present application. The technical solutions modified in this way do not change the basic concept of the present application and therefore fall within the protection scope of the present application.

[0108] The following refers to Figure 5 Another preferred embodiment of the control method of the present application is introduced.

[0109] As Figure 5 shown, corresponding to the second embodiment of the air conditioner, the control method of the present application comprises:

[0110] S301, obtaining the high pressure and the low pressure of the air conditioner. For example, the high pressure can be obtained by a pressure sensor arranged at the exhaust port of the compressor, and the low pressure can be obtained by a pressure sensor arranged at the suction port of the compressor.

[0111] S303, calculating the first ratio of the high pressure to the low pressure. For example, after obtaining the high pressure and the low pressure, the first ratio of the high pressure to the low pressure is calculated by dividing the high pressure by the low pressure.

[0112] S305, comparing the first ratio with a preset threshold. For example, after calculating the first ratio, the high-low pressure ratio of the air conditioning system can be obtained, and by comparing the high-low pressure ratio with the preset threshold, the pressure ratio of the current system can be determined, so as to determine the opening and closing mode of the on-off valve group suitable for the current situation, so as to adjust the opening and closing mode of the on-off valve group and adjust the pressure ratio of the system.

[0113] S307, selectively adjusting the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group based on the comparison result. For example, after determining the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group, the variable displacement compressor is controlled to switch mode, and each on-off valve in the on-off valve group is controlled to switch according to the opening and closing mode.

[0114] The control method of the application can automatically detect the system pressure ratio and adjust the opening and closing mode of the on-off valve group based on the system pressure ratio under different pressure ratios and loads of the system, so as to effectively adjust the system pressure, maintain the high and low pressure ratios of the system within a safe range threshold under the premise of ensuring the refrigeration effect, ensure the normal operation of the air conditioner, and improve the operation reliability of the compressor. The variable displacement compressor can be used to switch between multiple working modes during the system pressure adjustment process, so that the air conditioner operates more efficiently and stably.

[0115] The preferred technical solutions of the embodiment are described below.

[0116] In one embodiment, the step of "selectively adjusting the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group based on the comparison result" further comprises: if the first ratio is greater than the preset threshold, switching to the next working mode and opening and closing mode in a preset order based on the current working mode and opening and closing mode. Preferably, 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.

[0117] Specifically, the preset threshold can be any value in 2-10. In this application, the preset threshold is taken as 4.3 for example. After calculating the first ratio of the high pressure and the low pressure, it is judged whether the first ratio is less than or equal to the preset threshold 4.3. If the first ratio is less than or equal to 4.3, it proves that the high and low pressure ratio of the air conditioner is small and the system load is small, and the operation is stable, so the on-off valve group only needs to be controlled to maintain the current opening and closing state. Conversely, when the first ratio is greater than 4.3, the high and low pressure ratio of the system is large and the system load is large, and the risk of compressor operation is large, so the system pressure ratio needs to be reduced. At this time, the variable displacement compressor and the on-off valve group are switched to the next working mode and opening and closing mode in order. For example, if the current variable displacement compressor is in the two-stage mode and the on-off valve group is in the first mode, the compressor is controlled to switch to the two-cylinder mode and the on-off valve group remains in the first mode. Then the system high and low pressure ratio change is continuously detected, for example, every 30 seconds, and the first ratio is calculated again. If the first ratio is greater than 4.3, the variable displacement 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.

[0118] The above control method can automatically detect the system pressure ratio and control the pressure ratio and flow path change to realize real-time adjustment of the system pressure, ensure the refrigeration effect, maintain the pressure ratio within a safe range threshold, ensure the normal operation of the air conditioner, and improve the reliability of the compressor by controlling the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group in a preset order according to the current different high and low pressure ratios and loads of the air conditioner.

[0119] Of course, the above control method is only preferred, and those skilled in the art can also adjust it. For example, those skilled in the art can adjust the preset order, but as long as the heat exchange effect of the outdoor heat exchanger gradually decreases. For another example, those skilled in the art can also select the opening and closing mode of the on-off valve group according to the comparison table between the first ratio and the working mode of the variable displacement 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 can also be adjusted in reverse order of the preset order to balance the high and low pressure ratios of the system and the heat exchange effect.

[0120] In the preferred technical solution of the control method of the air conditioner, the control method further comprises: 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, then controlling the compressor to stop.

[0121] For example, in the process of controlling the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group in the above manner, if the on-off valve group has been switched to the fourth mode (at this time the variable displacement compressor must be in the double-cylinder mode), and at this time the first ratio of the system is still greater than the preset threshold, then at this time the compressor is controlled to stop to protect the compressor and avoid failure.

[0122] In the preferred technical solution of the control method of the air conditioner, before the step of "obtaining the high pressure and the low pressure of the air conditioner", the control method further comprises: obtaining the outdoor environment temperature and the running frequency of the variable displacement compressor; determining the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the running frequency; and controlling the variable displacement compressor and the on-off valve group to work based on the working mode and the opening and closing mode, respectively.

[0123] For example, when the air conditioner is started, the outdoor environment temperature is obtained by a temperature sensor, and the running frequency is obtained by the running information of the air conditioner. Of course, the specific obtaining method of the outdoor environment temperature and the running frequency of the compressor is not fixed, and those skilled in the art can adjust it as long as the two parameters can be obtained smoothly. After obtaining the outdoor environment temperature and the running frequency, the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group are determined based on the ranges in which they are located. Alternatively, the working mode and the opening and closing mode are determined based on the comparison relationship between the two and the variable displacement compressor and the on-off valve group. After determining the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group, the variable displacement compressor is controlled to switch modes, and each on-off valve in the on-off valve group is controlled to open and close according to the opening and closing mode.

[0124] By determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency, various shunt modes of the outdoor heat exchanger can be realized, the optimal shunt mode is adjusted according to the actual load, the performance is optimal, and the energy efficiency is optimal. By setting the variable displacement compressor, the variable displacement compressor can be used to switch between multiple working modes, so that the air conditioner runs more efficiently and stably.

[0125] In an embodiment, the step of "determining the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency" further comprises: if the outdoor environment 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 working mode of the variable displacement 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 environment temperature is less than or equal to the first temperature threshold and the operating frequency is greater than the first frequency threshold, determining that the working mode of the variable displacement compressor is a two-cylinder mode and the opening and closing mode of the on-off valve group is the first mode.

[0126] Specifically, the first temperature threshold is taken as 22℃, and the first frequency threshold is taken as 40Hz. When the outdoor environment temperature is less than or equal to 22℃ and the operating frequency is less than or equal to 40Hz, the startup load of the air conditioner is small at this time, and the working mode of the variable displacement compressor adopts a two-stage mode. In this mode, the variable displacement compressor can realize a larger compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirement and ensuring the refrigeration effect and efficiency of the air conditioner. The on-off valve group adopts the first mode. In this mode, the outdoor heat exchanger process is long, the supercooling section is large, the refrigerant flow rate is fast, the heat exchange capacity is large, the air conditioner power is low, and the energy efficiency is high. When the outdoor environment temperature is less than or equal to 22℃ and the operating frequency is greater than 40Hz, the startup load of the air conditioner is large, and the variable displacement compressor adopts a two-cylinder mode, which is lower in frequency under the same displacement. In this way, the high pressure of the air conditioning system is lowered, the low pressure is increased, and the compression ratio of the compressor is reduced. The on-off valve group adopts the first mode. In this mode, the outdoor temperature and the operating frequency of the compressor are moderate, which is efficient in cooperation with the two-cylinder mode of the compressor.

[0127] Of course, the above-mentioned first temperature threshold and first frequency threshold are not unique, and a person skilled in the art can adjust them based on specific application scenarios.

[0128] In an embodiment, the step of "determining the working mode of the variable displacement compressor and the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency" further comprises: if the outdoor environment temperature is greater than a first temperature threshold and the operating frequency is less than or equal to a second frequency threshold, determining that the working mode of the variable displacement 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 environment temperature is greater than the first temperature threshold and the operating frequency is greater than the second frequency threshold, determining that the working mode of the variable displacement compressor is a two-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.

[0129] Specifically, the first temperature threshold is taken as 22℃, and the second frequency threshold is taken as 60Hz. When the outdoor ambient temperature is greater than 22℃, and the operating frequency is less than or equal to 60Hz, the starting load of the air conditioner in the current temperature range is small at this time, and the variable displacement compressor adopts a two-stage mode. In this mode, the variable displacement compressor can achieve a larger compression ratio at a lower operating frequency, thereby meeting the condensing temperature requirement and ensuring the refrigeration effect and refrigeration efficiency of the air conditioner. The on-off valve group adopts the second mode. In this mode, the flow process is relatively short, the supercooling section is small, the flow rate is slow, the condensing temperature is low, and the power is low. The combination of the two can reduce the pipeline pressure drop and improve the heat exchange capacity. When the outdoor ambient temperature is greater than 22℃, and the operating frequency is greater than 60Hz, the starting load of the air conditioner in the current temperature range is large, and the variable displacement compressor adopts a two-cylinder mode. At the same displacement, the frequency is lower, so the high pressure of the air conditioning system is lower, the low pressure is higher, and the compression ratio of the compressor is reduced. The on-off valve group adopts the second mode. In this mode, the flow process is relatively short, the supercooling 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.

[0130] 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.

[0131] Those skilled in the art will understand that although some embodiments described herein include certain features included in other embodiments but not others, the combination of features of different embodiments means that it is within the scope of the present application and forms different embodiments. For example, in the claims of the present application, any one of the claimed embodiments can be used in any combination.

[0132] So far, the technical solution of the present application has been described in combination with the preferred embodiments shown in the drawings, but those skilled in the art will easily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to related technical features without departing from the principles of the present application, and the technical solutions after the changes or replacements will fall within the protection scope of the present application.

Claims

1. A control method of an air conditioner, characterized by, The air conditioner comprises a compressor, an outdoor heat exchanger, a throttling device and an indoor heat exchanger connected by refrigerant pipelines, the outdoor heat exchanger comprises a plurality of heat exchange pipe sections, and a switching valve group is further arranged in the outdoor heat exchanger, the switching valve group comprises a plurality of switching valves, and the switching valve group is arranged to be capable of controlling the communication form between the plurality of heat exchange pipe sections, The control method comprises: obtaining 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 value; based on the comparison result, selectively adjusting the opening and closing mode of the switching valve group; The outdoor heat exchanger comprises a first heat exchange pipe section, a second heat exchange pipe section and a third heat exchange pipe section connected in sequence, and further comprises a first branch pipe, a second branch pipe and a third branch pipe, a first end of the first branch pipe is communicated with a refrigerant pipe between the compressor and the first heat exchange pipe section, a second end of the first branch pipe is communicated with a refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section, a first end of the second branch pipe is communicated with the third branch pipe, a second end of the second branch pipe is communicated with one end of the third heat exchange pipe section close to the second heat exchange pipe section, a first end of the third branch pipe is communicated with a refrigerant pipe between the first heat exchange pipe section and the second heat exchange pipe section, and a second end of the third branch pipe is communicated with a refrigerant pipe between the third heat exchange pipe section and the throttling device, The switching valve group comprises a first switching valve, a second switching valve, a third switching valve and a fourth switching valve, the first switching valve is arranged in the first branch pipe, the second switching valve is arranged in the refrigerant pipe between the second heat exchange pipe section and the third heat exchange pipe section and located between the second end of the first branch pipe and the third heat exchange pipe section, the third switching valve is arranged in the second branch pipe, and the fourth switching valve is arranged in the third branch pipe and located between the first end of the second branch pipe and the second end of the third branch pipe; The opening and closing mode comprises a first mode, a second mode, a third mode and a fourth mode, wherein: The first mode is that the first switching valve is closed, the second switching valve is opened, the third switching valve is closed and the fourth switching valve is closed; The second mode is that the first switching valve is opened, the second switching valve is closed, the third switching valve is opened and the fourth switching valve is closed; The third mode is that the first switching valve is opened, the second switching valve is opened, the third switching valve is opened and the fourth switching valve is closed; The fourth mode is that the first switching valve is opened, the second switching valve is opened, the third switching valve is opened and the fourth switching valve is opened; Before the step of "obtaining high pressure and low pressure of the air conditioner", the control method further comprises: obtaining an outdoor environment temperature and a running frequency of the compressor; determining the opening and closing mode of the switching valve group based on the outdoor environment temperature and the running frequency; controlling the switching valve group to act based on the opening and closing mode.

2. The control method of the air conditioner according to claim 1, characterized by, The step of "based on the comparison result, selectively adjusting the opening and closing mode of the switching valve group" further comprises: If the first ratio is greater than the preset threshold value, switching to a next opening and closing mode in a preset order based on a current opening and closing mode.

3. The control method of the air conditioner according to claim 2, characterized by, The preset order is: the first mode, the second mode, the third mode and the fourth mode.

4. The control method of the air conditioner according to claim 3, characterized by, The control method further comprises: 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 value, stopping the compressor.

5. The control method of an air conditioner according to any one of claims 1 to 4, characterized by, The step of "determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency" further comprises: If the outdoor environment temperature is less than or equal to a first temperature threshold value and the operating frequency is less than or equal to a first frequency threshold value, determining the opening and closing mode of the on-off valve group as the first mode. If the outdoor environment temperature is less than or equal to the first temperature threshold value and the operating frequency is greater than the first frequency threshold value, determining the opening and closing mode of the on-off valve group as the second mode.

6. The control method of the air conditioner according to claim 5, characterized by, The step of "determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency" further comprises: If the outdoor environment temperature is greater than the first temperature threshold value and less than or equal to a second temperature threshold value and the operating frequency is less than or equal to a second frequency threshold value, determining the opening and closing mode of the on-off valve group as the first mode. If the outdoor environment temperature is greater than the first temperature threshold value and less than or equal to the second temperature threshold value and the operating frequency is greater than the second frequency threshold value, determining the opening and closing mode of the on-off valve group as the second mode. The second frequency threshold value is greater than the first frequency threshold value.

7. The control method of the air conditioner according to claim 6, characterized by, The step of "determining the opening and closing mode of the on-off valve group based on the outdoor environment temperature and the operating frequency" further comprises: If the outdoor environment temperature is greater than the second temperature threshold value and the operating frequency is less than or equal to a third frequency threshold value, determining the opening and closing mode of the on-off valve group as the first mode. If the outdoor environment temperature is greater than the second temperature threshold value and the operating frequency is greater than the third frequency threshold value, determining the opening and closing mode of the on-off valve group as the second mode. The third frequency threshold value is greater than the second frequency threshold value.

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