Method and device for determining liquid return of air conditioner compressor and air conditioner

Abstract

The present application relates to air conditioning technical field, provide a kind of air conditioner compressor's back liquid determination method, device and air conditioner, air conditioner compressor's back liquid determination method includes: obtaining the suction superheat of compressor and the oil concentration of compressor suction side;According to the suction superheat of compressor and the oil concentration of compressor suction side, it is determined whether compressor exists back liquid risk.The present application is by using the suction superheat of compressor and the oil concentration of compressor suction side to comprehensively determine whether compressor exists back liquid risk, can avoid the problem of high probability of single parameter misjudgment, improve the accuracy of back liquid risk determination of compressor, reach the purpose of protecting compressor, to ensure the reliability of air conditioner normal operation.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to a method, apparatus and air conditioner for determining liquid return in an air conditioner compressor. Background Technology

[0002] Currently, when air conditioners are operating at low temperatures, the compressor often experiences liquid return, which can easily damage the compressor and affect the normal operation of the air conditioner.

[0003] In related technologies, to avoid compressor liquid return, the main method is to calculate the compressor's exhaust superheat to determine whether there is a risk of compressor liquid return. However, this method has a high probability of misjudgment. Summary of the Invention

[0004] This invention provides a method, device, and air conditioner for determining liquid return in an air conditioner compressor, which solves the problem of high misjudgment probability of compressor liquid return risk in related technologies. It can improve the accuracy of determining compressor liquid return risk, achieve the purpose of protecting the compressor, and thus ensure the reliability of normal operation of the air conditioner.

[0005] This invention provides a method for determining liquid return in an air conditioner compressor, comprising:

[0006] Obtain the compressor suction superheat and the oil concentration on the compressor suction side;

[0007] Based on the compressor's suction superheat and the oil concentration on the compressor's suction side, it is determined whether the compressor has a risk of liquid return.

[0008] According to a method for determining liquid return in an air conditioner compressor provided by the present invention, the step of determining whether there is a risk of liquid return in the compressor based on the superheat of the compressor's suction and the oil concentration on the suction side of the compressor includes:

[0009] If the superheat of the compressor's suction is determined to be less than a preset temperature, and the oil concentration on the compressor's suction side is less than a preset concentration, then the compressor is deemed to have a risk of liquid return, and the liquid return risk is classified as a Level 1 liquid return risk.

[0010] According to a method for determining liquid return in an air conditioner compressor provided by the present invention, the step of determining whether there is a risk of liquid return in the compressor based on the compressor's suction superheat and the oil concentration on the compressor's suction side further includes:

[0011] The duration for which the superheat of the compressor's suction gas remains below a preset temperature, and the duration for which the oil concentration on the suction side of the compressor remains below a preset concentration, are obtained.

[0012] If the compressor's suction superheat is determined to be below a preset temperature for a duration greater than or equal to a first preset duration, and the oil concentration on the compressor's suction side is determined to be below a preset concentration for a duration greater than or equal to a second preset duration, then the compressor is deemed to have a risk of liquid return, and the liquid return risk is classified as a secondary liquid return risk.

[0013] The risk of secondary liquid return is higher than that of primary liquid return.

[0014] According to a method for determining liquid return in an air conditioner compressor provided by the present invention, the step of determining whether there is a risk of liquid return in the compressor based on the superheat of the compressor's suction and the oil concentration on the suction side of the compressor includes:

[0015] If the superheat of the compressor's suction is determined to be greater than or equal to a preset temperature, and the oil concentration on the compressor's suction side is determined to be greater than or equal to a preset concentration, then the compressor is deemed to have no risk of liquid return.

[0016] The method for determining liquid return in an air conditioner compressor according to the present invention further includes:

[0017] If it is determined that there is a risk of liquid return to the compressor, the air conditioner is controlled to execute a liquid return protection strategy.

[0018] According to the present invention, a method for determining liquid return in an air conditioner compressor includes a liquid return protection strategy comprising:

[0019] Increase the opening of the electronic expansion valve of the air conditioner, and / or increase the operating frequency of the compressor.

[0020] According to the present invention, a method for determining liquid return in an air conditioner compressor includes the step of increasing the opening of the electronic expansion valve of the air conditioner, comprising:

[0021] Once it is determined that the suction superheat of the compressor reaches a first preset temperature and the oil concentration on the suction side of the compressor reaches a first preset concentration, the electronic expansion valve of the air conditioner is controlled to operate at a first preset opening.

[0022] Once it is determined that the superheat of the compressor's suction reaches a second preset temperature and the oil concentration on the compressor's suction side reaches a second preset concentration, the electronic expansion valve of the air conditioner is controlled to operate at a second preset opening.

[0023] Once it is determined that the superheat of the compressor's suction reaches a third preset temperature and the oil concentration on the compressor's suction side reaches a third preset concentration, the electronic expansion valve of the air conditioner is controlled to operate at a third preset opening.

[0024] Wherein, the first preset temperature is greater than the second preset temperature, and the second preset temperature is greater than the third preset temperature; the first preset concentration is greater than the second preset concentration, and the second preset concentration is greater than the third preset concentration; the first preset opening degree is less than the second preset opening degree, and the second preset opening degree is less than the third preset opening degree.

[0025] According to the present invention, a method for determining liquid return in an air conditioner compressor, the step of increasing the operating frequency of the compressor includes:

[0026] Once it is determined that the superheat of the compressor's suction reaches a first preset temperature and the oil concentration on the compressor's suction side reaches a first preset concentration, the compressor is controlled to operate at a first preset frequency.

[0027] Once it is determined that the superheat of the compressor's suction reaches a second preset temperature and the oil concentration on the compressor's suction side reaches a second preset concentration, the compressor is controlled to operate at a second preset frequency.

[0028] If the superheat of the compressor's suction reaches a third preset temperature and the oil concentration on the compressor's suction side reaches a third preset concentration, control the compressor to operate at a third preset frequency.

[0029] Wherein, the first preset temperature is greater than the second preset temperature, and the second preset temperature is greater than the third preset temperature; the first preset concentration is greater than the second preset concentration, and the second preset concentration is greater than the third preset concentration; the first preset frequency is less than the second preset frequency, and the second preset frequency is less than the third preset frequency.

[0030] The present invention also provides a liquid return determination device for an air conditioner compressor, comprising:

[0031] The acquisition module is used to acquire the compressor's suction superheat and the oil concentration on the compressor's suction side;

[0032] The determination module is used to determine whether there is a risk of liquid return in the compressor based on the superheat of the compressor's suction and the oil concentration on the suction side of the compressor.

[0033] The present invention also provides an air conditioner, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the above-described method for determining the return liquid of the air conditioner compressor.

[0034] The present invention provides a method, device and air conditioner for determining liquid return in an air conditioner compressor. By using the superheat of the compressor intake and the oil concentration on the intake side of the compressor to comprehensively determine whether there is a risk of liquid return in the compressor, it can avoid the problem of high probability of misjudgment by a single parameter in related technologies, improve the accuracy of determining the risk of liquid return in the compressor, achieve the purpose of protecting the compressor, and thus ensure the reliability of the normal operation of the air conditioner. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in this invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is one of the flowcharts illustrating the liquid return determination method for an air conditioner compressor provided by the present invention;

[0037] Figure 2 This is the second flowchart of the method for determining liquid return in an air conditioner compressor provided by the present invention;

[0038] Figure 3 This is the third flowchart of the method for determining liquid return in an air conditioner compressor provided by the present invention;

[0039] Figure 4 This is a schematic diagram of the liquid return determination device for an air conditioner compressor provided by the present invention.

[0040] Figure 5 This is a schematic diagram of the structure of the air conditioner provided by the present invention.

[0041] Figure label:

[0042] 410: Acquisition module; 420: Judgment module; 430: Control module;

[0043] 510: Processor; 520: Communication interface;

[0044] 530: Memory; 540: Communication bus. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] In the description of the embodiments of the present invention, it should be noted that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0048] The following is combined Figures 1-5 The present invention describes a method, apparatus, and air conditioner for determining liquid return in an air conditioner compressor.

[0049] According to an embodiment of the first aspect of the present invention, referring to Figure 1 As shown, the present invention provides a method for determining liquid return in an air conditioner compressor, which mainly includes the following steps:

[0050] S100: Obtain the compressor suction superheat and the oil concentration on the compressor suction side.

[0051] Specifically, the compressor's suction superheat can be calculated by detecting the evaporator temperature and the compressor's suction temperature. Furthermore, an oil concentration sensor can be installed in the compressor's suction line to detect the oil concentration on the suction side. It's understood that oil concentration refers to the concentration of the compressor's lubricating oil.

[0052] S200. Based on the compressor's suction superheat and the oil concentration on the compressor's suction side, determine whether there is a risk of liquid return to the compressor.

[0053] When the compressor of an air conditioner is running, the compressor's lubricating oil circulates together with the refrigerant. The return of liquid to the compressor usually refers to the phenomenon that the liquid refrigerant in the evaporator returns to the compressor through the suction pipe on the suction side of the compressor when the compressor is running; and during the return of liquid, the lubricating oil also returns to the compressor through the suction pipe on the suction side of the compressor.

[0054] Liquid refrigerant return risk typically occurs when refrigerant flows back into the compressor in liquid form and mixes with the lubricating oil. When a large amount of liquid refrigerant is drawn into the compressor, the lubricating oil is diluted to a sufficiently low level, resulting in insufficient lubrication of the compressor bearings and accelerated wear. This can lead to increased compressor current, increased noise and vibration, and ultimately, compressor damage.

[0055] Therefore, the air conditioner compressor liquid return determination method provided in this embodiment of the invention can fully, effectively and accurately determine whether there is a risk of liquid return in the compressor by comprehensively utilizing the compressor's suction superheat and the oil concentration on the compressor's suction side.

[0056] For example, when the suction superheat is low, it indicates that there may be liquid refrigerant on the suction side of the compressor, which means there may be a risk of liquid return. When the oil concentration on the suction side of the compressor is low, it indicates that the oil on the suction side of the compressor is diluted by a large amount of liquid refrigerant. Therefore, it can be determined that there is liquid refrigerant on the suction side of the compressor, thus accurately judging that there is a risk of liquid return in the compressor.

[0057] Therefore, the liquid return determination method for air conditioner compressors provided in this embodiment of the invention can avoid the problem of high probability of misjudgment of a single parameter in related technologies, improve the accuracy of determining the risk of liquid return to the compressor, achieve the purpose of protecting the compressor, and thus ensure the reliability of normal operation of the air conditioner.

[0058] According to one embodiment of the present invention, referring to Figure 2 As shown, step S200, which determines whether there is a risk of liquid return to the compressor based on the compressor's suction superheat and the oil concentration on the compressor's suction side, includes:

[0059] S201. If the compressor's suction superheat is less than the preset temperature and the oil concentration on the compressor's suction side is less than the preset concentration, it is determined that the compressor has a risk of liquid return, and the liquid return risk is a level one liquid return risk.

[0060] Specifically, when the compressor's suction superheat is less than the preset temperature, such as less than 0°C, it indicates that the suction superheat is low, and there may be liquid refrigerant on the compressor suction side, which may pose a risk of liquid return. In this case, the oil concentration on the compressor suction side can be further determined. When the oil concentration on the compressor suction side is less than the preset concentration, that is, when the oil concentration is low, it indicates that the oil on the compressor suction side has been diluted by a large amount of liquid refrigerant. Thus, it can be determined that there is liquid refrigerant on the compressor suction side, thereby accurately determining the risk of liquid return in the compressor.

[0061] According to one embodiment of the present invention, referring to Figure 2 As shown, step S200, which determines whether there is a risk of liquid return to the compressor based on the compressor's suction superheat and the oil concentration on the compressor's suction side, further includes:

[0062] S202. Obtain the duration for which the compressor's suction superheat is continuously lower than a preset temperature, and the duration for which the oil concentration on the compressor's suction side is continuously lower than a preset concentration.

[0063] S203. If the duration of the compressor’s suction superheat being lower than the preset temperature is greater than or equal to the first preset duration, and the duration of the oil concentration on the compressor’s suction side being lower than the preset concentration is greater than or equal to the second preset duration, it is determined that the compressor has a risk of liquid return, and the liquid return risk is a secondary liquid return risk; wherein, the secondary liquid return risk is higher than the primary liquid return risk.

[0064] Because feedback from parameters such as temperature may be delayed, it can affect the determination of liquid return risk. Therefore, this embodiment of the invention obtains the compressor's suction superheat and the duration for which the oil concentration on the compressor's suction side remains below a preset value. If this duration reaches the preset value, it indicates that there is indeed a risk of liquid return, and the risk is higher at this point, meaning the accuracy of the liquid return risk determination is higher.

[0065] Therefore, the embodiments of the present invention can determine the degree of liquid return risk, effectively improve the accuracy of compressor liquid return risk determination, achieve the purpose of protecting the compressor, and thus ensure the reliability of normal operation of the air conditioner.

[0066] According to one embodiment of the present invention, referring to Figure 2 As shown, step S200, which determines whether there is a risk of liquid return to the compressor based on the compressor's suction superheat and the oil concentration on the compressor's suction side, includes:

[0067] S204. If the compressor’s suction superheat is greater than or equal to the preset temperature and the oil concentration on the compressor’s suction side is greater than or equal to the preset concentration, it is determined that the compressor has no risk of liquid return.

[0068] Specifically, when the compressor's suction superheat is greater than or equal to the preset temperature, such as greater than or equal to 0°C, it indicates that the suction superheat is high. There may be no liquid refrigerant on the compressor suction side, meaning there may be no risk of liquid return. In this case, the oil concentration on the compressor suction side can be further judged. When the oil concentration on the compressor suction side is greater than or equal to the preset concentration, that is, when the oil concentration is high, it indicates that the oil on the compressor suction side is diluted by liquid refrigerant to a very low degree. Thus, it can be determined that there is very little liquid refrigerant on the compressor suction side, thereby accurately determining that the compressor has virtually no risk of liquid return.

[0069] According to one embodiment of the present invention, referring to Figure 1 As shown, the method for determining liquid return in an air conditioner compressor according to the present invention further includes the following steps:

[0070] S300: If it is determined that there is a risk of liquid return to the compressor, control the air conditioner to execute the liquid return protection strategy.

[0071] When there is a risk of liquid return to the compressor, it can easily damage the compressor. In this case, the air conditioner will activate the liquid return protection function, implement the liquid return protection strategy, reduce the liquid return phenomenon, and thus protect the compressor.

[0072] According to one embodiment of the present invention, referring to Figure 3 As shown, the liquid return protection strategy includes the following steps:

[0073] S301. Increase the opening of the electronic expansion valve of the air conditioner, and / or increase the operating frequency of the compressor.

[0074] When there is a risk of liquid refrigerant returning to the compressor, it indicates that there is liquid refrigerant on the compressor suction side. In this case, by increasing the opening of the air conditioner's electronic expansion valve and / or increasing the compressor's operating frequency, the refrigerant vaporization effect can be improved, the liquid refrigerant content on the compressor suction side can be reduced, thereby reducing the risk of liquid refrigerant returning, effectively protecting the compressor, and extending its service life.

[0075] According to one embodiment of the present invention, the step of increasing the opening of the electronic expansion valve of an air conditioner includes: determining that the suction superheat of the compressor reaches a first preset temperature and the oil concentration on the suction side of the compressor reaches a first preset concentration, and controlling the electronic expansion valve of the air conditioner to operate at a first preset opening; determining that the suction superheat of the compressor reaches a second preset temperature and the oil concentration on the suction side of the compressor reaches a second preset concentration, and controlling the electronic expansion valve of the air conditioner to operate at a second preset opening; determining that the suction superheat of the compressor reaches a third preset temperature and the oil concentration on the suction side of the compressor reaches a third preset concentration, and controlling the electronic expansion valve of the air conditioner to operate at a third preset opening.

[0076] Among them, the first preset temperature is greater than the second preset temperature, the second preset temperature is greater than the third preset temperature; the first preset concentration is greater than the second preset concentration, the second preset concentration is greater than the third preset concentration; the first preset opening degree is less than the second preset opening degree, the second preset opening degree is less than the third preset opening degree.

[0077] Specifically, when it is determined that there is a risk of liquid return to the compressor, that is, the superheat of the compressor suction is less than the preset temperature, and the oil concentration on the compressor suction side is less than the preset concentration, the superheat of suction and the oil concentration are further detected. When they are less than the preset values, the lower the superheat of suction and the oil concentration, the higher the risk of liquid return, and the larger the opening of the electronic expansion valve is. This achieves precise adjustment of the liquid return protection, reduces the risk of liquid return, and reduces interference with the normal operation of the air conditioner.

[0078] According to one embodiment of the present invention, the step of increasing the operating frequency of a compressor includes: determining that the compressor's suction superheat reaches a first preset temperature and the oil concentration on the compressor's suction side reaches a first preset concentration, and controlling the compressor to operate at a first preset frequency; determining that the compressor's suction superheat reaches a second preset temperature and the oil concentration on the compressor's suction side reaches a second preset concentration, and controlling the compressor to operate at a second preset frequency; determining that the compressor's suction superheat reaches a third preset temperature and the oil concentration on the compressor's suction side reaches a third preset concentration, and controlling the compressor to operate at a third preset frequency.

[0079] Among them, the first preset temperature is greater than the second preset temperature, the second preset temperature is greater than the third preset temperature; the first preset concentration is greater than the second preset concentration, the second preset concentration is greater than the third preset concentration; the first preset frequency is less than the second preset frequency, the second preset frequency is less than the third preset frequency.

[0080] Specifically, when it is determined that there is a risk of liquid return to the compressor, that is, the superheat of the compressor suction is less than the preset temperature, and the oil concentration on the compressor suction side is less than the preset concentration, the superheat of suction and the oil concentration are further detected. When they are less than the preset values, the lower the superheat of suction and the oil concentration, the higher the risk of liquid return, and the higher the operating frequency of the compressor. This achieves precise adjustment of liquid return protection, reduces the risk of liquid return, and reduces interference with the normal operation of the air conditioner.

[0081] The liquid return determination device for an air conditioner compressor provided by the present invention will be described below. The liquid return determination device for an air conditioner compressor described below can be referred to in correspondence with the liquid return determination method for an air conditioner compressor described above.

[0082] According to an embodiment of the second aspect of the present invention, referring to Figure 4 As shown, the present invention also provides a liquid return determination device for an air conditioner compressor, mainly comprising: an acquisition module 410 and a determination module 420. The acquisition module 410 is used to acquire the compressor's suction superheat and the oil concentration on the compressor's suction side; the determination module 420 is used to determine whether the compressor has a risk of liquid return based on the compressor's suction superheat and the oil concentration on the compressor's suction side.

[0083] The air conditioner compressor liquid return determination device provided in this embodiment of the invention comprehensively determines whether there is a risk of liquid return to the compressor by acquiring the compressor's suction superheat and the oil concentration on the compressor's suction side. This avoids the problem of high probability of misjudgment based on a single parameter, improves the accuracy of determining the risk of liquid return to the compressor, achieves the purpose of protecting the compressor, and thus ensures the reliability of the air conditioner's normal operation.

[0084] According to one embodiment of the present invention, the liquid return determination device for the air conditioner compressor of the present invention further includes: a control module 430, used to control the air conditioner to execute a liquid return protection strategy to reduce the liquid return phenomenon when it is determined that there is a risk of liquid return to the compressor, thereby achieving the purpose of protecting the compressor.

[0085] According to an embodiment of the third aspect of the present invention, referring to Figure 5 As shown, the present invention also provides an air conditioner, which may include: a processor 510, a communication interface 520, a memory 530, and a communication bus 540, wherein the processor 510, the communication interface 520, and the memory 530 communicate with each other through the communication bus 540. The processor 510 can call logical instructions in the memory 530 to execute a liquid return determination method for the air conditioner compressor. The determination method includes: obtaining the compressor's suction superheat and the oil concentration on the compressor's suction side; and determining whether the compressor has a risk of liquid return based on the compressor's suction superheat and the oil concentration on the compressor's suction side.

[0086] Furthermore, the logical instructions in the aforementioned memory 530 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0087] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the liquid return determination method for the air conditioner compressor provided by the above methods. The determination method includes: obtaining the suction superheat of the compressor and the oil concentration on the suction side of the compressor; and determining whether there is a risk of liquid return to the compressor based on the suction superheat of the compressor and the oil concentration on the suction side of the compressor.

[0088] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program implements a liquid return determination method for an air conditioner compressor provided by the above methods. The determination method includes: obtaining the compressor's suction superheat and the oil concentration on the compressor's suction side; and determining whether the compressor has a risk of liquid return based on the compressor's suction superheat and the oil concentration on the compressor's suction side.

[0089] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0090] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of determining a return of liquid in an air conditioner compressor, characterized by, The method comprises the following steps: obtaining the suction superheat of the compressor and the oil concentration on the suction side of the compressor, wherein the oil concentration refers to the lubricating oil concentration of the compressor; determining whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor; the step of determining whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor comprises: determining that the compressor has a risk of liquid return and the risk of liquid return is a first-level risk of liquid return when the suction superheat of the compressor is less than a preset temperature and the oil concentration on the suction side of the compressor is less than a preset concentration.

2. The method of claim 1, wherein, the step of determining whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor further comprises: obtaining the duration for which the suction superheat of the compressor is less than a preset temperature and the duration for which the oil concentration on the suction side of the compressor is less than a preset concentration; determining that the compressor has a risk of liquid return and the risk of liquid return is a second-level risk of liquid return when the duration for which the suction superheat of the compressor is less than a preset temperature is greater than or equal to a first preset duration and the duration for which the oil concentration on the suction side of the compressor is less than a preset concentration is greater than or equal to a second preset duration; wherein the second-level risk of liquid return is higher than the first-level risk of liquid return.

3. The method of claim 1, wherein the method further comprises: the step of determining whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor comprises: determining that the compressor has no risk of liquid return when the suction superheat of the compressor is greater than or equal to a preset temperature and the oil concentration on the suction side of the compressor is greater than or equal to a preset concentration.

4. The method of claim 1-2, wherein, the method further comprises: controlling the air conditioner to execute a liquid return protection strategy when it is determined that the compressor has a risk of liquid return.

5. The method for determining liquid return in an air conditioner compressor according to claim 4, characterized in that, the liquid return protection strategy comprises: increasing the opening degree of an electronic expansion valve of the air conditioner and / or increasing the operating frequency of the compressor.

6. The method of claim 5, wherein the method further comprises: the step of increasing the opening degree of the electronic expansion valve of the air conditioner comprises: controlling the electronic expansion valve of the air conditioner to operate at a first preset opening degree when the suction superheat of the compressor reaches a first preset temperature and the oil concentration on the suction side of the compressor reaches a first preset concentration; controlling the electronic expansion valve of the air conditioner to operate at a second preset opening degree when the suction superheat of the compressor reaches a second preset temperature and the oil concentration on the suction side of the compressor reaches a second preset concentration; controlling the electronic expansion valve of the air conditioner to operate at a third preset opening degree when the suction superheat of the compressor reaches a third preset temperature and the oil concentration on the suction side of the compressor reaches a third preset concentration; wherein the first preset temperature is greater than the second preset temperature, the second preset temperature is greater than the third preset temperature, the first preset concentration is greater than the second preset concentration, the second preset concentration is greater than the third preset concentration, the first preset opening degree is less than the second preset opening degree, and the second preset opening degree is less than the third preset opening degree.

7. The method for determining liquid return in an air conditioner compressor according to claim 5, characterized in that, the step of increasing the operating frequency of the compressor comprises: determining that the suction superheat of the compressor reaches a first preset temperature and the oil concentration on the suction side of the compressor reaches a first preset concentration, and controlling the compressor to operate at a first preset frequency; determining that the suction superheat of the compressor reaches a second preset temperature and the oil concentration on the suction side of the compressor reaches a second preset concentration, and controlling the compressor to operate at a second preset frequency; determining that the suction superheat of the compressor reaches a third preset temperature and the oil concentration on the suction side of the compressor reaches a third preset concentration, and controlling the compressor to operate at a third preset frequency; wherein the first preset temperature is greater than the second preset temperature, the second preset temperature is greater than the third preset temperature, the first preset concentration is greater than the second preset concentration, the second preset concentration is greater than the third preset concentration, the first preset frequency is less than the second preset frequency, and the second preset frequency is less than the third preset frequency.

8. A device for determining liquid return in an air conditioner compressor, characterized in that, comprising: an acquisition module configured to acquire the suction superheat of the compressor and the oil concentration on the suction side of the compressor; a determination module configured to determine whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor; the step of determining whether the compressor has a risk of liquid return according to the suction superheat of the compressor and the oil concentration on the suction side of the compressor, comprising: determining that the suction superheat of the compressor is less than a preset temperature and the oil concentration on the suction side of the compressor is less than a preset concentration, and determining that the compressor has a risk of liquid return, which is a first-level risk of liquid return.

9. An air conditioner comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to realize the method for determining the risk of liquid return of the compressor of the air conditioner according to any one of claims 1-7.

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