Air conditioning unit control method and device and air conditioning unit

Abstract

The invention discloses an air conditioning unit control method and device and an air conditioning unit. A grounding wire of a compressor of the air conditioning unit is connected with a micro-current sensor in series, and the micro-current sensor is used for detecting leakage current of the compressor; the method comprises the steps of obtaining leakage current of the compressor; determining the current oil level of the compressor according to the leakage current of the compressor; and controlling the compressor to return oil according to the current oil level of the compressor. The problem that in the prior art, oil level detection of compressor lubricating oil is not accurate enough is solved, the accuracy of oil level detection and control of the compressor lubricating oil is improved, and the lubricating effect of the compressor is improved.

Description

Technical Field

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

[0002] At present, the heat pump air conditioning field is increasingly pursuing ultra-low temperature heating. With the lower and lower ambient temperature and higher and higher outlet water temperature requirements, the challenges to the compressor lubricating oil are also getting higher and higher. At present, the oil return problem under severe working conditions can be solved by increasing the oil content, but under some working conditions, it will cause serious high and low pressure cross-flow. Therefore, the existing solution is to add a solenoid valve for control, but how to accurately control it is a big problem.

[0003] As shown above, the compressor lubrication condition needs to be considered during the development and operation of small and medium-sized refrigeration and heat pump units. The lubricating oil level is an important indicator of the compressor lubrication condition. There are two main existing methods for determining the lubrication condition. One is to use a special sight glass compressor for testing and observe the operating window in real time. The other is to dissect a conventional compressor for life test to determine whether it is damaged and further infer whether there is oil shortage. The above scheme has the problem of inaccurate oil level inspection results and failure to determine the oil shortage in time, which is not conducive to the use and development of heat pump units.

[0004] With regard to the problem of inaccurate oil level detection of compressor lubricating oil in related technologies, no effective solution has been proposed so far. Summary of the invention

[0005] The present invention provides an air conditioning unit control method, device and air conditioning unit, so as to at least solve the problem of inaccurate oil level detection of compressor lubricating oil in the prior art.

[0006] To solve the above technical problems, according to one aspect of an embodiment of the present invention, a method for controlling an air-conditioning unit is provided, wherein a micro-current sensor is connected in series to the grounding wire of the compressor of the air-conditioning unit for detecting the leakage current of the compressor; the method comprises: obtaining the leakage current of the compressor; determining the current oil level of the compressor according to the leakage current of the compressor; and controlling the compressor to return oil according to the current oil level of the compressor.

[0007] Furthermore, the current oil level of the compressor is determined based on the leakage current of the compressor, including: obtaining the exhaust temperature of the compressor and the intra-cavity pressure of the compressor; determining an oil level correction coefficient based on the exhaust temperature and the intra-cavity pressure; and calculating the product of the oil level correction coefficient and the leakage current as the current oil level of the compressor.

[0008] Further, the oil level correction coefficient is determined according to the exhaust temperature and the intra-cavity pressure, including: calculating the oil level correction coefficient a by the following formula: a=λ*T0 / (α+β*ln(P0)), wherein λ is the total correction coefficient, T0 is the exhaust temperature, P0 is the intra-cavity pressure, α is the first pressure correction coefficient, and β is the second pressure correction coefficient.

[0009] Furthermore, before determining the oil level correction coefficient according to the exhaust temperature and the intra-cavity pressure, it also includes: obtaining a preset range of the total correction coefficient and determining the total correction coefficient within the preset range; or obtaining a preset value of the total correction coefficient, calculating the ambient temperature influence factor through the ambient temperature, and calculating the product of the ambient temperature influence factor and the preset value as the total correction coefficient; wherein the ambient temperature influence factor is equal to the product of the ambient temperature and a preset ratio.

[0010] Furthermore, controlling the compressor to return oil according to the current oil level of the compressor includes: obtaining the factory oil level of the compressor; calculating the oil level ratio of the current oil level of the compressor to the factory oil level; and controlling the compressor to return oil according to the oil level ratio.

[0011] Furthermore, the air-conditioning unit is also provided with an oil return valve for controlling the compressor to return oil; controlling the compressor to return oil according to the oil level ratio includes: detecting whether the oil level ratio is less than a first preset ratio for a first continuous preset time; if so, controlling the oil return valve to open; otherwise, controlling the oil return valve to close.

[0012] Furthermore, after controlling the oil return valve to open, it also includes: detecting whether the oil level ratio is greater than or equal to a second preset ratio within a second consecutive preset time; if so, closing the oil return valve; otherwise, detecting whether the oil level ratio is less than the first preset ratio within a third consecutive preset time, and when the oil level ratio is less than the first preset ratio within the third consecutive preset time, a compressor oil shortage reminder is issued.

[0013] According to another aspect of an embodiment of the present invention, there is provided an air-conditioning unit control device, in which a micro-current sensor is connected in series to the grounding line of the compressor of the air-conditioning unit for detecting the leakage current of the compressor; the device comprises: an acquisition module for acquiring the leakage current of the compressor; a determination module for determining the current oil level of the compressor according to the leakage current of the compressor; and a control module for controlling the compressor to return oil according to the current oil level of the compressor.

[0014] According to another aspect of the embodiments of the present invention, there is provided an air conditioning unit, comprising the air conditioning unit control device as described above.

[0015] According to another aspect of an embodiment of the present invention, there is provided a storage medium comprising computer executable instructions, wherein the computer executable instructions are used to execute the air conditioning unit control method as described above when executed by a computer processor.

[0016] In the present invention, a control scheme for an air-conditioning unit is provided, in which a micro-current sensor is connected in series to the grounding wire of the compressor of the air-conditioning unit to detect the leakage current of the compressor, and then the current oil level of the compressor is determined according to the leakage current of the compressor, and the compressor is controlled to return oil. When the oil level of the compressor changes, the insulation resistance of the compressor changes, and thus the leakage current detected by the micro-current sensor changes. The oil level can be determined according to the detection value of the micro-current sensor, and then the compressor is controlled to return oil according to the oil level to avoid oil shortage in the compressor. The above scheme detects the change of the oil level in time through the micro-current sensor, and because the micro-current sensor has a high precision, the oil level of the compressor is accurately determined, avoiding the problem of inaccurate oil level detection of the compressor lubricating oil in the prior art, improving the accuracy of the oil level detection and control of the compressor lubricating oil, improving the lubrication effect of the compressor, avoiding the wear of the compressor caused by oil shortage, and improving the operating stability of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of an optional structure of an air conditioning unit according to an embodiment of the present invention;

[0018] Figure 2 is an optional flow chart of an air conditioning unit control method according to an embodiment of the present invention;

[0019] Figure 3 is another optional flow chart of the air conditioning unit control method according to an embodiment of the present invention;

[0020] Figure 4 This is an optional structural block diagram of an air conditioning unit control device according to an embodiment of the present invention.

[0021] Description of reference numerals:

[0022] 1. Compressor; 2. Exhaust temperature sensor; 3. Pressure sensor; 4. Oil separator; 5. Four-way valve; 6. Fin heat exchanger; 7. Electronic expansion valve; 8. Auxiliary expansion valve; 9. Economizer; 10. Shell and tube heat exchanger; 11. Water flow switch; 12. Gas-liquid separator; 13. Oil return solenoid valve; 14. Controller; 15. Microcurrent sensor; 16. Ambient temperature sensor. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0025] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0026] It should be understood that although the terms first, second, third, etc. may be used to describe controllers in embodiments of the present invention, these controllers should not be limited to these terms. These terms are only used to distinguish controllers connected to different devices. For example, without departing from the scope of embodiments of the present invention, a first controller may also be referred to as a second controller, and similarly, a second controller may also be referred to as a first controller.

[0027] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0028] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0029] The optional embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Example 1

[0031] In a preferred embodiment 1 of the present invention, an oil return control method for an air-conditioning unit is provided, and the control method can be directly applied to various air-conditioning units with compressors. When implemented specifically, it can be achieved by installing software, APP in the air-conditioning unit or other devices, or writing a corresponding program into the controller.

[0032] Figure 1 An optional structural diagram of the air conditioning unit is shown, such as Figure 1 As shown, a micro-current sensor 15 is connected in series to the grounding line of the compressor of the air-conditioning unit of the present invention, which is used to detect the leakage current of the compressor and then determine the oil level of the compressor. In addition to the micro-current sensor 15, the air-conditioning unit also includes:

[0033] Compressor 1, exhaust temperature sensor 2, pressure sensor 3, oil separator 4, four-way valve 5, fin heat exchanger 6, electronic expansion valve 7, auxiliary expansion valve 8, economizer 9, shell and tube heat exchanger 10, water flow switch 11, gas-liquid separator 12, oil return solenoid valve 13, controller 14, environmental temperature sensing package 16.

[0034] The present invention can be applied to most air-conditioning equipment systems with compressors (oil-lubricated). The system operation is as follows: the refrigerant sucks in the gaseous refrigerant from the air intake port under the action of the compressor 1 and is compressed into a high-temperature and high-pressure refrigerant. After passing through the exhaust temperature sensor 2 and the pressure sensor 3, it enters the oil separator 4 to complete the oil-liquid separation. The lubricating oil then flows back to the compressor intake port according to the on-off status of the solenoid valve 13. After the refrigerant continues to flow into the four-way valve 5 (the subsequent description takes the heating mode as an example), it flows into the shell and tube heat exchanger 10 for heat release and cooling, then flows into the economizer for supercooling and then passes through the electronic expansion valve 7 and the auxiliary expansion valve 8 respectively, and is sent to the fin heat exchanger 6 for evaporation, and then flows back to the gas-liquid separator 12.

[0035] When the equipment is shut down, the oil return solenoid valve 13 remains in a fully closed state to ensure that the high and low pressures of the compressor can be quickly established during the startup process.

[0036] Based on the above air conditioning unit, Figure 2 An optional flow chart of the air conditioning unit control method is shown as follows: Figure 2 As shown, the method includes the following steps S202-S206:

[0037] S202: Obtaining leakage current of the compressor;

[0038] S204: determining a current oil level of the compressor according to the leakage current of the compressor;

[0039] S206: Controlling the compressor to return oil according to the current oil level of the compressor.

[0040] In the above embodiment, an air-conditioning unit control scheme is provided, by connecting a micro-current sensor in series on the grounding wire of the compressor of the air-conditioning unit to detect the leakage current of the compressor, and then determining the current oil level of the compressor according to the leakage current of the compressor, and controlling the compressor to return oil. When the oil level of the compressor changes, the insulation resistance of the compressor changes, and thus the leakage current detected by the micro-current sensor changes. The oil level can be determined according to the detection value of the micro-current sensor, and then the compressor is controlled to return oil according to the oil level to avoid oil shortage in the compressor. The above scheme detects the change of the oil level in time through the micro-current sensor, and because the micro-current sensor has a high precision, the oil level of the compressor is accurately determined, avoiding the problem of inaccurate oil level detection of the compressor lubricating oil in the prior art, improving the accuracy of the oil level detection and control of the compressor lubricating oil, improving the lubrication effect of the compressor, avoiding compressor wear caused by oil shortage, and improving the operating stability of the compressor.

[0041] Based on the leakage current detected by the micro-current sensor, the current oil level of the compressor is determined according to the leakage current of the compressor, including: obtaining the exhaust temperature of the compressor and the intra-cavity pressure of the compressor; determining the oil level correction coefficient according to the exhaust temperature and the intra-cavity pressure; calculating the product of the oil level correction coefficient and the leakage current as the current oil level of the compressor. The present invention uses a micro-current sensor, which detects the current value, and the oil level can only be obtained after correction processing of relevant influencing factors. The correction process uses the exhaust temperature of the compressor and the intra-cavity pressure of the compressor. The exhaust temperature of the compressor and the intra-cavity pressure of the compressor are both affected by the oil level. Therefore, through simulation calculation, the oil level correction coefficient is obtained, and then the accurate oil level is obtained.

[0042] Specifically, the oil level correction coefficient is determined according to the exhaust temperature and the cavity pressure, including: calculating the oil level correction coefficient a by the following formula: a=λ*T0 / (α+β*ln(P0)), wherein λ is the total correction coefficient, T0 is the exhaust temperature, P0 is the cavity pressure, α is the first pressure correction coefficient, and β is the second pressure correction coefficient. α and β are temperature and pressure correction coefficients, which are fitted by the refrigerant characteristics. The above formula is a preferred calculation method obtained by simulation calculation. Through the above formula, the oil level correction coefficient can be obtained to correct the oil level and obtain the accurate value of the current oil level.

[0043] Furthermore, before determining the oil level correction coefficient according to the exhaust temperature and the cavity pressure, it also includes: obtaining a preset range of the total correction coefficient, determining the total correction coefficient within the preset range; or obtaining a preset value of the total correction coefficient, calculating the ambient temperature influence factor through the ambient temperature, and calculating the product of the ambient temperature influence factor and the preset value as the total correction coefficient; wherein the ambient temperature influence factor is equal to the product of the ambient temperature and the preset ratio. In the formula, λ is the total correction coefficient, and the value can be selected as 1 to 1.5, which is determined by the characteristics of the system lubricating oil and the refrigerant. At the same time, the total correction coefficient will be mainly affected by the ambient temperature. The correction coefficient can be set by itself (1 to 1.5), and can also be adaptively adjusted according to the ambient temperature sensing package (Ts). The calculation formula can be λ = γ * Ts / 273, where γ is the actual measured value of the equipment, which can be 0.95. Through the above formula, the total correction coefficient can be accurately adjusted by the ambient temperature that affects the correction coefficient, and the optimal value of the total correction coefficient under different working conditions can be obtained in accordance with the changes in the actual scene (ambient temperature), thereby obtaining the accurate value of the oil level.

[0044] In another preferred embodiment of the present invention, the compressor is controlled to return oil according to the current oil level of the compressor, including: obtaining the factory oil level of the compressor; calculating the oil level ratio of the current oil level of the compressor to the factory oil level; and controlling the compressor to return oil according to the oil level ratio. The oil level ratio of the current oil level of the compressor to the factory oil level can reflect the change and amount of the oil level. When the ratio is low, it means that the lubricating oil has been reduced a lot, and when the ratio is high, it means that the lubricating oil has not been reduced much, so that the corresponding oil return control is performed to make the lubricating oil level reach the optimal position.

[0045] like Figure 1 As shown, the air conditioning unit is also provided with an oil return valve (solenoid valve) for controlling the compressor to return oil; controlling the compressor to return oil according to the oil level ratio includes: detecting whether the oil level ratio is less than the first preset ratio for a continuous first preset time; if so, controlling the oil return valve to open; otherwise, controlling the oil return valve to close. In order to ensure the accuracy of the oil return control, the oil return is performed when the oil level ratio is less than the first preset ratio for a continuous first preset time, avoiding frequent adjustments or unnecessary adjustments caused by frequent fluctuations in the oil level within a small range or inaccurate detection values, and ensuring the accuracy of the oil level adjustment.

[0046] In addition, after controlling the oil return valve to open, it also includes: detecting whether the oil level ratio is greater than or equal to the second preset ratio within the second consecutive preset time; if so, closing the oil return valve; otherwise, detecting whether the oil level ratio is less than the first preset ratio within the third consecutive preset time, and when the oil level ratio is less than the first preset ratio within the third consecutive preset time, a compressor oil shortage reminder is issued. If the oil level ratio is less than the first preset ratio at any time and the duration is greater than or equal to the third preset time, the unit alarm prompts, and the content may be: the system lacks refrigeration oil, please contact the staff for investigation, so as to promptly remind the user to maintain the compressor lubricating oil to avoid compressor wear caused by lack of oil in the compressor.

[0047] Another air conditioning unit control method is provided in the preferred embodiment 1 of the present invention. Specifically, Figure 3 An optional flow chart of the method is shown as follows: Figure 3 As shown, the method includes the following steps S301-S308:

[0048] S301: Before the equipment leaves the factory, use direct detection (by means of sight glass) to run and test the highest oil level a1;

[0049] S302: After on-site installation and commissioning, test run is performed, and the oil level height a under similar working conditions is detected at the same time, and whether oil return is required is determined according to H=a / a1;

[0050] S303: Is H<A true? If so, proceed to step S304; otherwise, proceed to step S308;

[0051] S304: Open the oil return valve;

[0052] S305: Whether the duration ≥ 2h is established, if yes, proceed to step S306, otherwise proceed to step S307;

[0053] S306: Prompt the user: There is an abnormality in the system, please contact the staff for on-site inspection in time;

[0054] S307: Is H≥B established? If yes, proceed to step S308; otherwise, proceed to step S304;

[0055] S308: Clear the prompt, close the oil return solenoid valve, and the equipment operates normally.

[0056] In the above embodiment, the equipment is tested by direct detection (by means of a sight glass) before leaving the factory to determine the maximum oil level a1, and the relative height of the refrigerant oil H=a / a1*100% is calculated. At any time during normal operation, when it is detected that H<A and the continuous duration is T1, the solenoid valve opens. Similarly, when it is detected that H≥B and the duration is greater than T2, the return oil valve is closed. If H is less than A at any time and the duration is greater than or equal to 2h, the unit will report a warning message, which may be: The system lacks refrigerant oil, please contact the staff for investigation. When the condition H≥B is met and the duration is greater than T2, the warning message can be cleared. A, B, T1, and T2 are specific values ​​for the equipment, which can be 30%, 50%, 30, or 40.

[0057] In the above control scheme, the detection sensing technology of the refrigerant oil level height is used to determine the opening timing of the return oil solenoid valve and correct the interference of influencing factors, which can fundamentally solve the problem of inaccurate compressor oil level detection, achieve reliable and accurate oil return, and improve the reliability of compressor control and operation.

[0058] Example 2

[0059] Based on the air conditioning unit control method provided in the above embodiment 1, a preferred embodiment 2 of the present invention further provides an air conditioning unit control device, specifically, Figure 4 An optional structural block diagram of the device is shown, such as Figure 4 As shown, the device comprises:

[0060] An acquisition module 402 is used to acquire the leakage current of the compressor;

[0061] A determination module 404, connected to the acquisition module 402, for determining a current oil level of the compressor according to the leakage current of the compressor;

[0062] The control module 406 is connected to the determination module 404 and is used to control the compressor to return oil according to the current oil level of the compressor.

[0063] In the above embodiment, an air-conditioning unit control scheme is provided, by connecting a micro-current sensor in series on the grounding wire of the compressor of the air-conditioning unit to detect the leakage current of the compressor, and then determining the current oil level of the compressor according to the leakage current of the compressor, and controlling the compressor to return oil. When the oil level of the compressor changes, the insulation resistance of the compressor changes, and thus the leakage current detected by the micro-current sensor changes. The oil level can be determined according to the detection value of the micro-current sensor, and then the compressor is controlled to return oil according to the oil level to avoid oil shortage in the compressor. The above scheme detects the change of the oil level in time through the micro-current sensor, and because the micro-current sensor has a high precision, the oil level of the compressor is accurately determined, avoiding the problem of inaccurate oil level detection of the compressor lubricating oil in the prior art, improving the accuracy of the oil level detection and control of the compressor lubricating oil, improving the lubrication effect of the compressor, avoiding compressor wear caused by oil shortage, and improving the operating stability of the compressor.

[0064] The determination module 404 includes: a first acquisition unit, used to obtain the exhaust temperature of the compressor and the intra-cavity pressure of the compressor; a determination unit, used to determine the oil level correction coefficient based on the exhaust temperature and the intra-cavity pressure; and a first calculation unit, used to calculate the product of the oil level correction coefficient and the leakage current as the current oil level of the compressor.

[0065] The determination unit includes: calculating the oil level correction coefficient a by the following formula: a=λ*T0 / (α+β*ln(P0)), wherein λ is the total correction coefficient, T0 is the exhaust temperature, P0 is the cavity pressure, α is the first pressure correction coefficient, and β is the second pressure correction coefficient.

[0066] The determination module 404 also includes: a correction unit, which is used to obtain a preset range of the total correction coefficient before determining the oil level correction coefficient based on the exhaust temperature and the intra-cavity pressure, and determine the total correction coefficient within the preset range; or, obtain a preset value of the total correction coefficient, calculate the ambient temperature influence factor through the ambient temperature, and calculate the product of the ambient temperature influence factor and the preset value as the total correction coefficient; wherein the ambient temperature influence factor is equal to the product of the ambient temperature and the preset ratio.

[0067] The control module 406 includes: a second acquisition unit for acquiring the factory oil level of the compressor; a second calculation unit for calculating the oil level ratio between the current oil level of the compressor and the factory oil level; and a control unit for controlling the compressor to return oil according to the oil level ratio.

[0068] Furthermore, the air-conditioning unit is also provided with an oil return valve for controlling the compressor to return oil; the control unit includes: a first control subunit, for detecting whether the oil level ratio is less than a first preset ratio for a continuous first preset time; if so, controlling the oil return valve to open; otherwise, controlling the oil return valve to close.

[0069] The control unit also includes: a second control subunit, which is used to detect whether the oil level ratio is greater than or equal to the second preset ratio within the second consecutive preset time after controlling the return oil valve to open; if so, close the return oil valve; otherwise, detect whether the oil level ratio is less than the first preset ratio within the third consecutive preset time, and when the oil level ratio is less than the first preset ratio within the third consecutive preset time, issue an oil shortage reminder for the compressor.

[0070] Regarding the device in the above embodiment, the specific manner in which each unit and module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0071] Example 3

[0072] Based on the air conditioning unit control device provided in the above-mentioned embodiment 2, in a preferred embodiment 3 of the present invention, an air conditioning unit is further provided, comprising the air conditioning unit control device as described above.

[0073] In the above embodiment, an air-conditioning unit control scheme is provided, by connecting a micro-current sensor in series on the grounding wire of the compressor of the air-conditioning unit to detect the leakage current of the compressor, and then determining the current oil level of the compressor according to the leakage current of the compressor, and controlling the compressor to return oil. When the oil level of the compressor changes, the insulation resistance of the compressor changes, and thus the leakage current detected by the micro-current sensor changes. The oil level can be determined according to the detection value of the micro-current sensor, and then the compressor is controlled to return oil according to the oil level to avoid oil shortage in the compressor. The above scheme detects the change of the oil level in time through the micro-current sensor, and because the micro-current sensor has a high precision, the oil level of the compressor is accurately determined, avoiding the problem of inaccurate oil level detection of the compressor lubricating oil in the prior art, improving the accuracy of the oil level detection and control of the compressor lubricating oil, improving the lubrication effect of the compressor, avoiding compressor wear caused by oil shortage, and improving the operating stability of the compressor.

[0074] Example 4

[0075] Based on the air conditioning unit control method provided in the above-mentioned embodiment 1, a storage medium containing computer executable instructions is also provided in a preferred embodiment 4 of the present invention. When the computer executable instructions are executed by a computer processor, they are used to execute the air conditioning unit control method as described above.

[0076] In the above embodiment, an air-conditioning unit control scheme is provided, by connecting a micro-current sensor in series on the grounding wire of the compressor of the air-conditioning unit to detect the leakage current of the compressor, and then determining the current oil level of the compressor according to the leakage current of the compressor, and controlling the compressor to return oil. When the oil level of the compressor changes, the insulation resistance of the compressor changes, and thus the leakage current detected by the micro-current sensor changes. The oil level can be determined according to the detection value of the micro-current sensor, and then the compressor is controlled to return oil according to the oil level to avoid oil shortage in the compressor. The above scheme detects the change of the oil level in time through the micro-current sensor, and because the micro-current sensor has a high precision, the oil level of the compressor is accurately determined, avoiding the problem of inaccurate oil level detection of the compressor lubricating oil in the prior art, improving the accuracy of the oil level detection and control of the compressor lubricating oil, improving the lubrication effect of the compressor, avoiding compressor wear caused by oil shortage, and improving the operating stability of the compressor.

[0077] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0078] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0079] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0080] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0081] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0082] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0083] Those skilled in the art will readily appreciate other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art that are not invented by the present invention. The specification and examples are to be considered exemplary only, and the true scope and spirit of the present invention are indicated by the following claims.

[0084] It should be understood that the present invention is not limited to the exact construction that has been described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for controlling an air conditioning unit, characterized in that: A micro-current sensor is connected in series to the grounding line of the compressor of the air-conditioning unit to detect the leakage current of the compressor; the method comprises: obtaining a leakage current of the compressor; determining a current oil level of the compressor according to a leakage current of the compressor; The compressor is controlled to return oil according to the current oil level of the compressor.

2. The method according to claim 1, characterized in that Determining a current oil level of the compressor according to a leakage current of the compressor includes: Acquiring the exhaust temperature of the compressor and the pressure in the cavity of the compressor; determining an oil level correction coefficient according to the exhaust temperature and the cavity pressure; The product of the oil level correction coefficient and the leakage current is calculated as the current oil level of the compressor.

3. The method according to claim 2, characterized in that Determining an oil level correction coefficient according to the exhaust temperature and the cavity pressure includes: The oil level correction coefficient a is calculated by the following formula: a=λ*T0 / (α+β*ln(P0)), wherein λ is the total correction coefficient, T0 is the exhaust temperature, P0 is the cavity pressure, α is the first pressure correction coefficient, and β is the second pressure correction coefficient.

4. The method according to claim 3, characterized in that Before determining the oil level correction coefficient according to the exhaust temperature and the cavity pressure, the method further includes: Obtaining a preset range of the total correction coefficient, and determining the total correction coefficient within the preset range; or, Obtain a preset value of the total correction coefficient, calculate the ambient temperature influence factor according to the ambient temperature, and calculate the product of the ambient temperature influence factor and the preset value as the total correction coefficient; wherein the ambient temperature influence factor is equal to the product of the ambient temperature and the preset ratio.

5. The method according to claim 1, characterized in that Controlling the compressor to return oil according to the current oil level of the compressor includes: Obtaining the factory oil level of the compressor; Calculating the oil level ratio of the current oil level of the compressor to the factory oil level; The compressor is controlled to return oil according to the oil level ratio.

6. The method according to claim 5, characterized in that The air conditioning unit is also provided with an oil return valve for controlling the compressor to return oil; controlling the compressor to return oil according to the oil level ratio includes: Detecting whether the oil level ratio is less than a first preset ratio for a continuous first preset time; If yes, control the oil return valve to open; Otherwise, the oil return valve is controlled to be closed.

7. The method according to claim 6, characterized in that After controlling the oil return valve to open, the method further comprises: Detecting whether the oil level ratio is greater than or equal to a second preset ratio within a second preset time period; If yes, closing the oil return valve; Otherwise, it is detected whether the oil level ratio is smaller than the first preset ratio within a third consecutive preset time, and when the oil level ratio is smaller than the first preset ratio within the third consecutive preset time, a compressor oil shortage reminder is issued.

8. An air conditioning unit control device, characterized in that: A micro-current sensor is connected in series to the grounding line of the compressor of the air-conditioning unit to detect the leakage current of the compressor; the device comprises: An acquisition module, used for acquiring the leakage current of the compressor; a determination module, configured to determine a current oil level of the compressor according to a leakage current of the compressor; The control module is used to control the compressor to return oil according to the current oil level of the compressor.

9. An air conditioning unit, characterized in that: It comprises the air conditioning unit control device as claimed in claim 8.

10. A storage medium containing computer executable instructions, characterized in that: The computer executable instructions are used to execute the air conditioning unit control method according to any one of claims 1 to 7 when executed by a computer processor.

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