Air conditioning system and control method thereof

Abstract

The embodiment of the application provides an air conditioning system and a control method thereof, and relates to the technical field of air conditioning systems. The air conditioning system comprises an outdoor unit, a controller and at least one indoor unit. The outdoor unit comprises a compressor and a current sensor connected to the compressor. The controller is configured to: in response to the start of the compressor, acquire the operating frequency of the compressor; count the operating time when the operating frequency is outside the rated frequency interval; after the operating time is greater than a first preset time, read the first current value flowing through the compressor detected by the current sensor every interval preset time period; determine the operating state of the compressor according to the operating time and the first current value; and control the compressor to return oil when the compressor is in an oil shortage operating state. The air conditioning system provided by the embodiment of the application can accurately determine the operating state of the compressor, and can timely control the compressor to return oil when the compressor is in an oil shortage operating state, thereby avoiding affecting the normal operation of the compressor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning systems, and in particular to an air conditioning system and a control method thereof. BACKGROUND

[0002] The compressor is a core component of the air conditioning system, and its working performance directly affects the operation effect of the air conditioning system. Inside the compressor, lubricating oil is generally injected for lubrication to reduce the friction between the internal parts of the compressor, so that the movement between the parts is smoother and the wear of the parts is reduced. During the operation of the compressor, the lubricating oil in the compressor will be discharged together with the refrigerant, into the system condenser, piping or evaporator. Only the discharged lubricating oil can be smoothly brought back to the compressor, so as to maintain the dynamic balance of the lubricating oil in the compressor. If the oil return of the compressor is insufficient, the compressor will be worn, affecting the service life of the compressor.

[0003] In the prior art, the oil return is usually controlled according to the operation time of the compressor, for example, the compressor is controlled to return oil every 8 hours of operation. However, the oil return control method of the prior art cannot control the oil return according to the actual operation condition of the compressor, which may cause the compressor to operate for a long time without oil when a certain time is reached, or the compressor may not lack oil when the oil return condition is reached, resulting in misjudgment and affecting the normal operation of the compressor. SUMMARY

[0004] The embodiments of the present application provide an air conditioning system and a control method thereof, which are used to determine the operation state of the compressor according to the operation frequency and the first current value, so as to avoid the lack of oil in the compressor affecting the normal operation of the air conditioning system.

[0005] In a first aspect, the embodiments of the present application provide an air conditioning system, comprising: an outdoor unit, a controller and at least one indoor unit; the outdoor unit comprises: a compressor and a current sensor connected with the compressor; the controller is configured to: in response to the start of the compressor, acquire the operation frequency of the compressor; count the operation time when the operation frequency is out of the rated frequency interval; after the operation time is greater than a first preset time, read the first current value flowing through the compressor detected by the current sensor every interval of a preset time period; determine the operation state of the compressor according to the operation time and the first current value; and control the compressor to start oil return when the compressor is in the oil shortage operation state.

[0006] The air conditioning system provided by the embodiments of the present application can determine the operation state of the compressor according to the operation frequency of the compressor and the first current value. Since the operation frequency of the compressor is related to the oil return amount of the compressor, and when the compressor is in the oil shortage state, the lubrication between the parts in the compressor is insufficient, and the first current value flowing through the compressor also changes. In the scheme disclosed in the present application, the controller can determine the operation state of the compressor according to the operation frequency of the compressor and the first current value flowing through the compressor. Once the compressor is in the oil shortage operation state, the controller can trigger the oil return of the compressor, so as to avoid the compressor being in the oil shortage operation state for a long time and affecting the operation effect of the air conditioning system.

[0007] With reference to the first implementation manner of the first aspect, the operation state of the compressor is determined according to the operation time and the first current value, including: determining a second current value according to the exhaust pressure of the compressor and the suction pressure of the compressor; determining a first current deviation value as a difference between the first current value and the second current value; generating a current deviation change rate, the current deviation change rate being a difference between the first current deviation value and a second current deviation value; the second current deviation value being related to the current flowing through the compressor before the first current value is read; and if a preset condition is met, determining that the compressor is in the oil shortage operation state, the preset condition being related to at least one of the first current deviation value, the current deviation change rate, and the operation time.

[0008] With reference to the second implementation manner of the first aspect, the preset condition includes at least one of: a time when the current deviation change rate is greater than a preset threshold value exceeding a second preset time, the first current deviation value being greater than a first preset deviation value, and the operation time being greater than a third preset time.

[0009] With reference to the third implementation manner of the first aspect, after the step of controlling the oil return of the compressor, the method further includes: counting the oil return time of the compressor; and controlling the compressor to stop the oil return when the oil return time reaches a fourth preset time.

[0010] With reference to the fourth implementation manner of the first aspect, after the step of controlling the oil return of the compressor, the controller is further configured to: count a time when the first current deviation value is less than a second preset deviation value, the second preset deviation value being less than the first preset deviation value; and control the compressor to stop the oil return when the time when the first current deviation value is less than the second preset deviation value reaches a fifth preset time.

[0011] With reference to the fifth implementation manner of the first aspect, the step of controlling the oil return of the compressor specifically includes: controlling the compressor to operate at a preset frequency, the preset frequency being within a rated frequency range.

[0012] In a second aspect, the embodiments of the present application provide a control method of an air conditioning system. The control method comprises: in response to starting of a compressor, acquiring a running frequency of the compressor; counting running time of the running frequency being outside a rated frequency interval; after the running time is greater than a first preset time, acquiring a first current value flowing through the compressor every preset time interval; determining a running state of the compressor according to the running time and the first current value; and controlling the compressor to start oil return when the compressor is in an oil shortage running state.

[0013] With reference to the first implementation manner of the second aspect, the determining of the running state of the compressor according to the running time and the first current value comprises: determining a second current value according to a discharge pressure of the compressor and a suction pressure of the compressor; determining a first current deviation value as a difference between the first current value and the second current value; generating a current deviation change rate, the current deviation change rate being a difference between the first current deviation value and a second current deviation value; the second current deviation value being related to the current flowing through the compressor before the first current value is acquired; and determining that the compressor is in the oil shortage running state if a preset condition is met, the preset condition being related to at least one of the first current deviation value, the current deviation change rate, and the running time.

[0014] With reference to the second implementation manner of the second aspect, the preset condition comprises at least one of the following: a time when the current deviation change rate is greater than a preset threshold value exceeding a second preset time, the first current deviation value being greater than a first preset deviation value, and the running time being greater than a third preset time.

[0015] With reference to the third implementation manner of the second aspect, after the step of controlling the compressor to return oil, the method further comprises: counting oil return time of the compressor; and controlling the compressor to stop oil return when the oil return time reaches a fourth preset time.

[0016] With reference to the fourth implementation manner of the second aspect, after the step of controlling the compressor to return oil, the control method further comprises: counting a time when the first current deviation value is less than a second preset deviation value, the second preset deviation value being less than the first preset deviation value; and controlling the compressor to stop oil return when the time when the first current deviation value is less than the second preset deviation value reaches a fifth preset time.

[0017] In a third aspect, the embodiments of the present application provide a controller. The controller comprises: one or more processors; and one or more memories. The one or more memories are configured to store computer program codes, the computer program codes comprising computer instructions. When the one or more processors execute the computer instructions, the controller performs any one of the control methods provided in the second aspect and possible implementation manners.

[0018] In a fourth aspect, an embodiment of the present application provides a computer readable storage medium, which comprises computer instructions. When the computer instructions are controlled on a computer, the computer executes any one of the control methods provided in the second aspect and possible implementation manners.

[0019] In a fifth aspect, an embodiment of the present application provides a computer program product, which can be directly loaded into a memory and contains software codes. The computer program product can realize the control method provided in the second aspect and possible implementation manners after being loaded and executed by a computer.

[0020] It should be noted that the computer instructions can be stored on the computer readable storage medium in whole or in part. The computer readable storage medium can be packaged together with the processor of the controller or packaged separately from the processor of the controller, and the present application does not limit this.

[0021] The beneficial effects of the second aspect to the fifth aspect of the present application are analyzed with reference to the beneficial effects of the first aspect, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0022] The accompanying drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and are used to explain the technical solutions of the present application together with the embodiments of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0023] Figure 1 A schematic diagram of a composition of an air conditioning system provided by an embodiment of the present application is shown in the following figure:

[0024] Figure 2 A schematic diagram of an installation position of a current sensor provided by an embodiment of the present application is shown in the following figure:

[0025] Figure 3 A schematic diagram of a structure of a current transformer provided by an embodiment of the present application is shown in the following figure:

[0026] Figure 4 A control flow of a controller of an air conditioning system provided by an embodiment of the present application is shown in the following figure: Figure 1 ;

[0027] Figure 5 A control flow of a controller of an air conditioning system provided by an embodiment of the present application is shown in the following figure: Figure 2 ;

[0028] Figure 6 A control flow of a controller of an air conditioning system provided by an embodiment of the present application is shown in the following figure: Figure 3 ;

[0029] Figure 7A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 4 ;

[0030] Figure 8 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 5 ;

[0031] Figure 9 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 6 ;

[0032] Figure 10 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 7 ;

[0033] Figure 11 A control flow of a controller of an air conditioning system provided for an embodiment of the present application

[0034] Figure 12 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 1 ;

[0035] Figure 13 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 2 ;

[0036] Figure 14 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 3 ;

[0037] Figure 15 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 4 ;

[0038] Figure 16 A control flow of a controller of an air conditioning system provided for an embodiment of the present application Figure 5 ;

[0039] Figure 17 A control flow of a controller of an air conditioning system provided for an embodiment of the present application

[0040] Figure 18 A control flow of a controller of an air conditioning system provided for an embodiment of the present application DETAILED DESCRIPTION

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0042] It should be noted that the terms "first" and "second" used in the embodiments of this invention are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0043] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, when describing pipelines, the terms "connected" and "linked" as used in this application have the meaning of establishing electrical connection. The specific meaning needs to be understood in conjunction with the context.

[0044] In the embodiments of this application, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design that is described as "exemplary" or "for example" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or design. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0045] Please see Figure 1 , Figure 1 This is a schematic diagram of an air conditioning system provided as a feasible embodiment.

[0046] like Figure 1 As shown, the air conditioning system may include: outdoor unit 10, controller ( Figure 1 (Not shown in the image) and indoor unit 20. Outdoor unit 10 and indoor unit 20 can be connected via pipes, etc.

[0047] The outdoor unit 10 includes: a compressor 11, a four-way reversing valve 12, an outdoor unit heat exchanger 13, an outdoor fan 14, an outdoor unit electronic expansion valve 15, a liquid-side shut-off valve 16, a gas-side shut-off valve 17, and a gas-liquid separator 18. The indoor unit 20 includes: an indoor unit electronic expansion valve 21, an indoor unit heat exchanger 22, and an indoor fan 23.

[0048] It is worth noting that Figure 1 It is worth noting that

[0049] In some embodiments, the compressor 11 is arranged between the four-way reversing valve 12 and the gas-liquid separator 18, for compressing the refrigerant and inputting the compressed refrigerant into the circulation system through the four-way reversing valve 12 to provide power for the circulation of the refrigerant.

[0050] In some embodiments, the four ports (C, D, S, E) of the four-way reversing valve 12 are respectively connected to the exhaust port of the compressor 11 (not shown in the figure), the outdoor heat exchanger 13, the gas-liquid separator 18, and the indoor heat exchanger 22 of each indoor unit.

[0051] The four-way reversing valve 12 is used to realize the mutual conversion between the cooling mode and the heating mode of the air conditioning system by changing the flow direction of the refrigerant in the system pipeline.

[0052] In some embodiments, one end of the outdoor heat exchanger 13 is connected to the compressor 11 through the four-way reversing valve 12, and the other end is connected to the indoor heat exchanger 22. The outdoor heat exchanger 13 is used for heat exchange between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 13 and the outdoor air to achieve the purpose of temperature adjustment.

[0053] In some embodiments, the outdoor fan 14 is connected to the outdoor fan (not shown in the figure) to drive or change the rotating speed of the outdoor fan to promote the heat exchange between the refrigerant flowing in the heat transfer pipe of the outdoor heat exchanger 13 and the outdoor air, and achieve the purpose of auxiliary temperature adjustment.

[0054] In some embodiments, the outdoor electronic expansion valve 15 and the indoor electronic expansion valve 21 are arranged between the indoor heat exchanger 22 and the outdoor heat exchanger 13. The outdoor electronic expansion valve 15 has the function of expanding and reducing the pressure of the refrigerant flowing through the outdoor electronic expansion valve 15, and can be used to adjust the flow of the refrigerant in the pipeline. Similarly, the indoor electronic expansion valve 21 has the function of expanding and reducing the pressure of the refrigerant flowing through the outdoor electronic expansion valve 21, and can be used to adjust the flow of the refrigerant in the pipeline.

[0055] In some embodiments, the liquid side stop valve 16 is arranged between the outdoor electronic expansion valve 15 and the indoor electronic expansion valve 21.

[0056] In some embodiments, the gas side stop valve 17 is arranged between the compressor 11 and the indoor heat exchanger 22.

[0057] In some embodiments, the gas-liquid separator 18 is connected to the compressor 11 for separating gaseous refrigerant and liquid refrigerant.

[0058] In some embodiments, the indoor heat exchanger 22 is configured to exchange heat between the refrigerant flowing in the heat transfer tube of the indoor heat exchanger 22 and indoor air.

[0059] In some embodiments, the indoor fan 23 is connected with an indoor fan (not shown in the figure) and is configured to drive or change the rotating speed of the indoor fan to facilitate the heat exchange between the refrigerant flowing in the heat transfer tube of the indoor heat exchanger 22 and the indoor air.

[0060] The controller is the control center of the air conditioning system 100 and can be configured to control the operation of various components in the air conditioning system 100 to enable the various components of the air conditioning system 100 to perform various functions of the air conditioning system 100.

[0061] In some embodiments, the controller refers to a device that can generate operation control signals according to instruction operation codes and timing signals to instruct the outdoor unit 10 and the indoor unit 20 to execute control instructions. For example, the controller can be a central processing unit (CPU), a general processor network processor (NP), a digital signal processing (DSP), a microprocessor, a microcontroller, a programmable logic device (PLD), or any combination thereof. The controller can also be other devices with processing functions, such as a circuit, a device, or a software module, and the embodiments of the present application do not make any limitation in this regard.

[0062] Those skilled in the art can understand that the hardware structure shown in the above Figure 1 The hardware structure shown in the above figure does not constitute a limitation on the air conditioning system, which can include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components, and the present application does not make any specific limitation in this regard.

[0063] As described in the background, the compressor is the core component of the air conditioning system, and its working performance directly affects the operation effect of the air conditioning system. In actual operation, due to the difference in operating frequency, the compressor may operate with insufficient oil. When the compressor operates at a high frequency for a long time, the oil discharge of the compressor will increase, while the oil return may not change. At this time, the lubricating oil in the oil pool of the compressor will gradually decrease after the compressor operates for a long time. When the compressor operates at a low frequency, the suction volume of the compressor decreases, which may cause the oil return of the compressor to decrease. If the compressor operates for a long time, the oil in the oil pool of the compressor may also decrease.

[0064] When the compressor operates at the rated frequency, the oil return amount and the oil discharge amount of the compressor gradually balance, and the oil amount remaining in the air conditioning system can be returned to the compressor oil pool. The existing control method cannot accurately determine whether the compressor is short of oil. It may be that the compressor has been running short of oil for a long time when a certain time is reached; it may also be that the compressor is not short of oil when the oil return condition is reached, resulting in a false judgment, affecting the load output of the unit and the use effect of the user.

[0065] Based on this, the air conditioning system provided by the embodiments of the present application further comprises a current sensor for detecting the current value flowing through the compressor. Please refer to Figure 2 , Figure 2 The installation position of the current sensor provided by the embodiments of the present application is shown in the schematic diagram. As Figure 2 shown, the current sensor 19 is arranged on the wiring harness 110 of the compressor 11.

[0066] As a feasible implementation manner, the current sensor 19 can be a current transformer. The current transformer is composed of a closed core and a winding. Please refer to Figure 3 , Figure 3 The structure of the current transformer provided by the embodiments of the present application is shown in the schematic diagram. As can be seen, the current transformer can be connected in series in the current line to be measured, so as to measure the current value flowing through the line.

[0067] Please refer to Figure 4 , in order for the compressor to operate normally, the air conditioning system provided by the embodiments of the present application, the controller is configured to perform S401-S405:

[0068] S401, in response to the start of the compressor, obtaining the operating frequency of the compressor.

[0069] S402, counting the operating time when the operating frequency is outside the rated frequency interval.

[0070] Since the oil discharge amount of the compressor increases when the compressor operates at a high frequency, that is, when the operating frequency is higher than the upper limit of the rated frequency interval, and the oil return amount may not change at this time, the lubricating oil in the compressor oil pool will gradually decrease after the compressor operates for a long time; when the compressor operates at a low frequency, that is, when the operating frequency is lower than the lower limit of the rated frequency interval, the suction amount of the compressor decreases, which may cause the oil return amount of the compressor to decrease, and if the compressor operates for a long time, the oil amount in the compressor oil pool may also decrease.

[0071] In summary, when the operating frequency of the compressor is outside the rated frequency interval, the oil amount in the compressor oil pool may decrease after a long time of operation, that is, the compressor is short of oil, and needs to be returned.

[0072] It should be understood that, in the embodiments of the present application, the rated frequency interval is pre-set by the system, and in actual application, the rated frequency interval can be set according to the characteristics of the compressor itself.

[0073] S403, after the running time is greater than the first preset time, reading the first current value flowing through the compressor detected by the current sensor every interval preset time period.

[0074] It should be understood that, in the embodiments of the present application, the first preset time and the preset time period are pre-set by the system, and in actual application, the first preset time and the preset time period can be set according to the requirements. For example, as a feasible implementation manner, the first preset time can be 5 minutes, and the preset time period can be 1 minute, and the first current value detected by the current sensor is read every 1 minute after the running frequency of the compressor is outside the rated frequency interval for 5 minutes.

[0075] Since the running frequency of the compressor is outside the rated frequency interval, the oil amount in the oil pool of the compressor may be reduced after a long time of operation. In order to further determine whether the compressor is out of oil, the first current value is obtained every interval preset time period, and whether the compressor is in an oil shortage running state is further determined according to the first current value flowing through the compressor.

[0076] S404, determining the running state of the compressor according to the running time and the first current value.

[0077] Since the rising and falling trend of the first current value of the compressor can also indicate the oil return state of the compressor. When the compressor returns oil normally, the load of the compressor increases, and the first current value has an increasing trend; in the case that the compressor returns oil insufficiently, the load of the compressor decreases, and the first current value has a decreasing trend.

[0078] Therefore, whether the compressor is in an oil shortage running state can be determined according to the running time of the compressor outside the rated frequency interval and the first current value flowing through the compressor.

[0079] As a feasible implementation manner, please refer to Figure 5 , S404 can be specifically implemented as S501-S504:

[0080] S501, obtaining the discharge pressure and suction pressure of the compressor, and determining the second current value according to the discharge pressure and suction pressure.

[0081] It should be noted that the air conditioning system needs to pre-store the corresponding relationship between the discharge pressure and suction pressure of the compressor and the second current value. As a feasible implementation manner, the functional relationship of the first current value Icom, the discharge pressure Pd and the suction pressure Ps of the compressor can be fitted according to the performance curve of the compressor, as shown in formula (1):

[0082] Icom = F(Pd, Ps) Equation (1)

[0083] That is, the corresponding relationship between the exhaust pressure Pd and the suction pressure Ps and the first current value of the compressor when the compressor is running at rated power.

[0084] As a feasible implementation manner, F(Pd, Ps) can be a binary linear equation, as shown in Equation (2):

[0085] F(Pd, Ps) = a*Pd + b*Ps + c Equation (2)

[0086] As another feasible implementation manner, F(Pd, Ps) can be a binary quadratic equation, as shown in Equation (3):

[0087] F(Pd, Ps) = a*Pd 2 +b*Ps 2 +c*Pd*Ps+d*Pd+e*Ps+f Equation (3)

[0088] Wherein a, b, c, d, e are constants.

[0089] After obtaining the exhaust pressure and the suction pressure of the compressor, the second current value of the compressor is determined according to the corresponding relationship between the exhaust pressure, the suction pressure and the second current value, that is, the first current value of the compressor when the compressor is in a normal running state.

[0090] It is worth noting that the embodiments of the present application only exemplarily introduce several implementation manners of determining the second current value, and the above implementation manners do not constitute specific limitations.

[0091] S502, determining the difference between the first current value and the second current value as a first current deviation value.

[0092] The difference between the first current value and the second current value of the compressor, that is, the difference between the actual current value and the theoretical current value of the compressor, is calculated as the first current deviation value.

[0093] S503, generating a current deviation change rate.

[0094] The current deviation change rate is the difference between the first current deviation value and the second current deviation value.

[0095] Wherein, the second current deviation value is related to the current flowing through the compressor before the first current value is read.

[0096] In some embodiments, the second current deviation value is the current deviation value before a preset time period, that is, the last calculated current deviation value.

[0097] If the current deviation value of the compressor continues to increase, it indicates that the compressor is experiencing a gradual oil deficiency process. Therefore, the difference between the first current deviation value and the second current deviation value is determined as the current deviation change rate, that is, the change value of the current deviation value.

[0098] S504, determine the running state of the compressor according to the first current deviation value, the current deviation change rate and the running time.

[0099] Since the first current deviation value represents the deviation of the actual current value of the compressor from the theoretical current value, the current deviation change rate is the change of the current deviation value of the compressor, and the running frequency is the intuitive response of the running state of the compressor, therefore, the running state of the compressor can be determined according to the first current deviation value, the current deviation change rate and the running frequency, and the running state of the compressor can be accurately determined.

[0100] As a feasible implementation manner, S504 can be specifically implemented as: if a preset condition is met, it is determined that the compressor is in an oil deficiency running state. Wherein, the preset condition includes at least one of: the time when the current deviation change rate is greater than the preset threshold value exceeds the second preset time, the first current deviation value is greater than the first preset deviation value, and the running time is greater than the third preset time.

[0101] As a feasible implementation manner, please refer to Figure 6 , S504 can be specifically implemented as:

[0102] S601, determine whether the current deviation change rate is greater than a preset threshold value.

[0103] If the current deviation change rate is greater than the preset threshold value, execute S602; if the current deviation change rate is less than or equal to the preset threshold value, it indicates that the compressor is in a normal running state.

[0104] S602, count the time when the current deviation change rate is greater than the preset threshold value.

[0105] When the compressor is short of oil, the moving parts of the compressor lack lubrication, and the first current value will gradually increase. Therefore, if the current deviation change rate is greater than the preset threshold value, that is, the current deviation value of the compressor continues to increase, it indicates that the compressor is experiencing a gradual oil deficiency process. Therefore, the time when the current deviation change rate is greater than the preset threshold value, that is, the time when the current deviation value of the compressor continues to increase, is counted.

[0106] S603, determine whether the time when the current deviation change rate is greater than the preset threshold value exceeds the second preset time.

[0107] If yes, execute S604; if no, it indicates that the compressor is in a normal running state.

[0108] S604, determining that the compressor is in an oil shortage running state.

[0109] When the compressor is in an oil shortage state, the moving parts of the compressor lack lubrication, and the first current value gradually increases. Therefore, if the time during which the current deviation change rate is greater than the preset threshold value exceeds the second preset time, that is, the current deviation value of the compressor continues to increase, it indicates that the compressor is in the process of gradually lacking oil. If the time during which the current deviation change rate continues to increase exceeds the second preset time, that is, the time during which the current deviation change rate is greater than the preset threshold value exceeds the second preset time, it indicates that the compressor is in an oil shortage running state.

[0110] It should be understood that, in the embodiments of the present application, the preset threshold value and the second preset time are preset by the system, and can be set according to requirements in actual application. For example, as a feasible implementation manner, the preset threshold value is 0.5, and the second preset time can be 2 minutes. When the time during which the current deviation change rate is greater than 0.5 exceeds 2 minutes, it is determined that the compressor is in an oil shortage running state.

[0111] As another feasible implementation manner, please refer to Figure 7 , S504 can be specifically implemented as:

[0112] S701, determining whether the first current deviation value is greater than a first preset deviation value.

[0113] If yes, S702 is executed; if no, it indicates that the compressor is in a normal running state.

[0114] S702, determining that the compressor is in an oil shortage running state.

[0115] Since the first current deviation value represents the deviation of the actual first current value of the compressor from the theoretical first current value, if the first current deviation value is greater than the first preset deviation value, it indicates that the first current value of the compressor has deviated greatly, that is, the compressor has been running in an oil shortage state.

[0116] It should be understood that, in the embodiments of the present application, the first preset deviation value is preset by the system, and the first preset deviation value can be set according to requirements in actual application. For example, as a feasible implementation manner, the first preset deviation value can be 1. If the first current deviation value is greater than 1, it indicates that the compressor is in an oil shortage running state.

[0117] As another feasible implementation manner, please refer to Figure 8 , S504 can be specifically implemented as:

[0118] S801, determining whether the running time is greater than a third preset time.

[0119] The third preset time is greater than the first preset time.

[0120] If the running time is greater than the third preset time, S802 is executed; otherwise, it indicates that the compressor is in a normal running state.

[0121] S802, determining that the compressor is in an oil shortage running state.

[0122] Since the running time is the time when the running frequency of the compressor is outside the rated frequency interval, the compressor may run for a long time outside the rated interval, which may cause the compressor to be short of oil. In order to avoid inaccurate detection of the first current value of the compressor, when the running time is greater than the third preset time, it is determined that the compressor is in an oil shortage running state, which can further ensure the stable running of the compressor.

[0123] It should be understood that in the embodiments of the present application, the third preset time is pre-set by the system and is greater than the first preset time. In actual application, the third preset time can be set according to the needs. For example, as a feasible implementation manner, the third preset time can be 10 minutes. After the running frequency of the compressor is outside the rated frequency interval for 10 minutes, it is determined that the compressor is in an oil shortage running state.

[0124] S405, controlling the compressor to start oil return when the compressor is in an oil shortage running state.

[0125] When the compressor is in an oil shortage running state, the lubricating oil in the oil pool of the compressor gradually decreases. The wear between the various parts inside the compressor will affect the service life of the compressor. Therefore, when the compressor is in an oil shortage running state, the compressor is controlled to start oil return. The discharged lubricating oil can be smoothly brought back to the compressor, maintaining the dynamic balance of the lubricating oil in the compressor.

[0126] As a feasible implementation manner, S405 can be specifically implemented as: controlling the compressor to run at a preset frequency.

[0127] It should be understood that the preset frequency is within the rated frequency interval, which is the best oil return frequency pre-set by the system.

[0128] Since when the compressor runs at a frequency within the rated frequency interval, the oil return amount and the oil discharge amount of the compressor will gradually balance, the lubricating oil remaining in the air conditioning system can be returned to the oil pool of the compressor. Therefore, the compressor is controlled to run at a preset frequency within the rated frequency interval, so that the discharged lubricating oil can be smoothly brought back to the compressor, maintaining the dynamic balance of the lubricating oil in the compressor.

[0129] It can be seen that the air conditioning system provided by the embodiment of the application can determine the running state of the compressor according to the running frequency and the first current value of the compressor. Since the running frequency of the compressor is closely related to the oil return amount and the oil discharge amount of the compressor, and when the compressor is short of oil, the parts inside the compressor lack lubrication, and the first current value will also change accordingly. Therefore, according to the running frequency and the first current value, whether the compressor is in a short-oil running state can be determined more accurately, and the compressor can be controlled to return oil in time to avoid affecting the normal operation of the compressor.

[0130] In some embodiments, after the compressor enters the oil return control mode for oil return, it is necessary to determine whether the oil return exit condition is met, that is, whether the discharged lubricating oil has been brought back to the compressor, to avoid long-time oil return of the compressor and affect the operation of the air conditioning system.

[0131] As a feasible implementation manner, please refer to Figure 9 After S405, the method provided by the embodiment of the application further includes:

[0132] S901, the oil return time of the compressor is counted.

[0133] S902, when the oil return time reaches the fourth preset time, the compressor is controlled to stop oil return.

[0134] Since the compressor needs to run at a rated frequency or change the opening degree of the electronic expansion valve when returning oil, regardless of which oil return scheme, it will affect the normal operation of the air conditioning system, for example, the refrigerating / heat capacity of the air conditioning system cannot reach the temperature required by the user. Therefore, the oil return time of the compressor needs to be counted, and when the oil return time reaches the fourth preset time, the compressor is controlled to stop oil return. This avoids long-time oil return of the compressor and affects the use effect of the user.

[0135] As another feasible implementation manner, please refer to Figure 10 After S405, the method provided by the embodiment of the application further includes:

[0136] S1001, the time when the first current deviation value is less than the second preset deviation value is counted.

[0137] S1002, when the time when the first current deviation value is less than the second preset deviation value reaches the fifth preset time, the compressor is controlled to stop oil return.

[0138] When the compressor is short of oil, the first current value also changes due to the lack of lubrication among the parts in the compressor. The first current deviation value can represent the deviation between the first current value and the second current value of the compressor, so when the first current deviation value is less than the second preset deviation value, it indicates that the compressor is gradually returning oil and the wear among the parts in the compressor is reduced. Therefore, when the time for the first current deviation value being less than the second preset deviation value reaches the fifth preset time, it indicates that the compressor has completed returning oil, and the compressor is controlled to stop returning oil.

[0139] It should be understood that in the embodiments of the present application, the second preset deviation value and the fifth preset time are preset by the system, and the second preset deviation value is less than the first preset deviation value. In actual application, the second preset deviation value and the fifth preset time can be set according to requirements. For example, as a feasible implementation manner, the second preset deviation value can be 0.5, and the fifth preset time can be 3 minutes. When the time for the first current deviation value being less than 0.5 reaches 3 minutes, it indicates that the compressor has completed returning oil, and the compressor is controlled to stop returning oil.

[0140] In some embodiments, referring to Figure 11 The air conditioning system provided by the embodiments of the present application comprises a controller configured to perform the following steps after the compressor starts operating:

[0141] S1101, count the running time T1.

[0142] The running time T1 is the time during which the operating frequency of the compressor is outside the rated frequency interval.

[0143] S1102, determine whether T1 is greater than Tmin.

[0144] The Tmin is a first preset time.

[0145] If yes, perform S1103; if no, it indicates that the compressor is in a normal operating state, and return to perform S1101.

[0146] S1103, determine whether a preset condition is met.

[0147] The preset condition comprises at least one of the following: whether the current deviation change rate Icom of the compressor is greater than I1 for a time exceeding T2, whether the first current deviation value AIcomt is greater than the first preset deviation value Imax, and whether the running time is greater than Tmax. 2

[0148] It should be understood that I1 is a preset threshold value; T2 is a second preset time, and Tmax is a third preset time.

[0149] ​If the preset condition is met, S1104 is performed; otherwise, it indicates that the compressor is in a normal operation state, and the process returns to S1102.

[0150] S1104, control the compressor to operate at a rated frequency.

[0151] S1105, determine whether the oil return time is greater than T3, or whether the first current deviation value is less than a second preset deviation value Imin.

[0152] T3 is a fourth preset time.

[0153] If yes, S1106 is performed; otherwise, S1104 is continuously performed.

[0154] S1106, control the compressor to stop oil return.

[0155] When the oil return time is greater than the fourth preset time, or the first current deviation value is less than the second preset deviation value, it indicates that the compressor has completed oil return, and the compressor is controlled to stop oil return.

[0156] The embodiment of the application also provides a control method of an air conditioning system, the air conditioning system comprising: an outdoor unit, a controller and at least one indoor unit, the outdoor unit comprising: a compressor and a current sensor connected with the compressor.

[0157] Please refer to Figure 12 , Figure 12 The method flowchart of the control method of the air conditioning system provided by the embodiment of the application. As shown in Figure 12 , the control method comprises the following steps:

[0158] S1201, in response to starting of the compressor, acquiring an operating frequency of the compressor.

[0159] S1202, counting operating time when the operating frequency is outside a rated frequency interval.

[0160] S1203, after the operating time is greater than a first preset time, acquiring a first current value flowing through the compressor every preset time interval.

[0161] S1204, determining an operating state of the compressor according to the operating time and the first current value.

[0162] S1205, when the compressor is in an oil shortage operating state, controlling the compressor to start oil return.

[0163] As a feasible implementation manner, please refer to Figure 13 , the method of determining the operating state of the compressor according to the operating time and the first current value comprises:

[0164] S1301, acquire the discharge pressure and suction pressure of the compressor, and determine a second current value according to the discharge pressure and the suction pressure.

[0165] S1302, determine a first current deviation value as a difference between the first current value and the second current value.

[0166] S1303, generate a current deviation change rate.

[0167] The current deviation change rate is a difference between the first current deviation value and a second current deviation value; the second current deviation value is a current deviation value before a preset time period.

[0168] S1304, determine the running state of the compressor according to the first current deviation value, the current deviation change rate, and a running time.

[0169] As a feasible implementation manner, the running state of the compressor is determined according to the first current deviation value, the current deviation change rate, and the running time, including: if a preset condition is met, it is determined that the compressor is in an oil shortage running state.

[0170] The preset condition includes at least one of that the time during which the current deviation change rate is greater than a preset threshold value exceeds a second preset time, the first current deviation value is greater than a first preset deviation value, and the running time is greater than a third preset time.

[0171] As a feasible implementation manner, please refer to Figure 14 S1304 can be specifically implemented as:

[0172] S1401, determine whether the current deviation change rate is greater than a preset threshold value.

[0173] If the current deviation change rate is greater than the preset threshold value, execute S1402; if the current deviation change rate is less than or equal to the preset threshold value, it indicates that the compressor is in a normal running state.

[0174] S1402, count the time during which the current deviation change rate is greater than the preset threshold value.

[0175] When the compressor is short of oil, the moving parts of the compressor lack lubrication, and the first current value will gradually increase. Therefore, if the current deviation change rate is greater than the preset threshold value, that is, the current deviation value of the compressor continues to increase, it indicates that the compressor is experiencing a gradual oil shortage process. Therefore, the time during which the current deviation change rate is greater than the preset threshold value, that is, the time during which the current deviation value of the compressor continues to increase, is counted.

[0176] S1403, determine whether the time during which the current deviation change rate is greater than the preset threshold value exceeds a second preset time.

[0177] If yes, execute S1404; if no, it indicates that the compressor is in a normal running state.

[0178] S1404, determine that the compressor is in an oil shortage running state.

[0179] As another possible implementation manner, S1304 can be specifically implemented as: if the first current deviation value is greater than the first preset deviation value, it is determined that the compressor is in an oil shortage running state.

[0180] As another possible implementation manner, S1304 can be specifically implemented as: if the running time is greater than the third preset time, it is determined that the compressor is in an oil shortage running state.

[0181] As a possible implementation manner, please refer to Figure 15 , after the step of controlling the compressor to enter the oil return control mode to return oil, the method further comprises:

[0182] S1501, count the oil return time of the compressor.

[0183] S1502, when the oil return time reaches the fourth preset time, control the compressor to stop returning oil.

[0184] As a possible implementation manner, please refer to Figure 16 , after the step of controlling the compressor to enter the oil return control mode to return oil, the method further comprises:

[0185] S1601, count the time when the first current deviation value is less than the second preset deviation value.

[0186] Wherein, the second preset deviation value is less than the first preset deviation value.

[0187] S1602, when the time when the first current deviation value is less than the second preset deviation value reaches the fifth preset time, control the compressor to stop returning oil.

[0188] As a possible implementation manner, the compressor is controlled to enter the oil return control mode to return oil, specifically: the compressor is controlled to run at a preset frequency, and the preset frequency is within the rated frequency interval.

[0189] The embodiment of the application also provides a control device of an air conditioning system, please refer to Figure 17 , the control device 1700 comprises: an acquisition module 1701 for acquiring the running frequency of the compressor; a counting module 1702 for counting the running time when the running frequency is outside the rated frequency interval; the acquisition module 1701 is also used for acquiring the first current value flowing through the compressor every interval preset time period after the running time is greater than the first preset time; a determination module 1703 for determining the running state of the compressor according to the running time and the first current value; a control module 1704 for controlling the compressor to start returning oil when the compressor is in an oil shortage running state.

[0190] The embodiments of the present application also provide an electronic device, please refer to Figure 18 The electronic device 180 includes one or more processors 1801, and one or more memories 1802, wherein the one or more memories 1802 are configured to store computer program codes, the computer program codes include computer instructions, and when the one or more processors 1801 execute the computer instructions, the electronic device 180 performs each step of the method shown in the above method embodiments.

[0191] The embodiments of the present application also provide a computer readable storage medium, the computer readable storage medium stores computer instructions, and when the computer instructions run on an electronic device, the electronic device performs each step of the method shown in the above method embodiments.

[0192] The embodiments of the present application also provide a computer program product, the computer program product includes computer instructions, and when the computer instructions run on an electronic device, the electronic device performs each step of the method shown in the above method embodiments.

[0193] In the above embodiments, all or part of the embodiments can be realized by software, hardware, firmware or any combination thereof. When realized by software, all or part of the embodiments can be realized in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer instructions are loaded and executed on a computer, all or part of the processes or functions according to the embodiments of the present application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network or other programmable device. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line (DSL) or wireless (such as infrared, wireless, microwave, etc.)) way. The computer readable storage medium can be any available medium that can be accessed by a computer or data storage device including one or more servers, data centers, etc. integrated with one or more media. The available medium can be magnetic medium (such as floppy disk, hard disk, magnetic tape), optical medium (such as DVD) or semiconductor medium (such as solid state disk (SSD)) and the like.

[0194] ​The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any change or replacement within the technical scope disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An air conditioning system, characterized by, Comprise: An outdoor unit, a controller and at least one indoor unit; The outdoor unit comprises: a compressor and a current sensor connected with the compressor; The controller is configured to: In response to the start of the compressor, obtain the operating frequency of the compressor; Statistical operating time of the operating frequency outside the rated frequency interval; After the operating time is greater than a first preset time, read the first current value flowing through the compressor detected by the current sensor every interval preset time period; Obtain the discharge pressure and suction pressure of the compressor; According to the corresponding relationship between the pre-stored discharge pressure and suction pressure and the second current value, determine the second current value; The difference between the first current value and the second current value is determined as the first current deviation value; Generate current deviation change rate, the current deviation change rate is the difference between the first current deviation value and the second current deviation value; the second current deviation value is related to the current flowing through the compressor before reading the first current value; If the preset condition is met, it is determined that the compressor is in an oil shortage running state; The preset condition includes at least one of the following: the time when the current deviation change rate is greater than a preset threshold value exceeds a second preset time, the first current deviation value is greater than a first preset deviation value, and the operating time is greater than a third preset time; When the compressor is in the oil shortage running state, control the compressor to start oil return.

2. The air conditioning system of claim 1, wherein, After the step of controlling the compressor to start oil return, the controller is further configured to: Statistical oil return time of the compressor; When the oil return time reaches a fourth preset time, control the compressor to stop oil return.

3. The air conditioning system according to any one of claims 1-2, wherein After the step of controlling the compressor to return oil, the controller is further configured to: Statistical time when the first current deviation value is less than a second preset deviation value, the second preset deviation value is less than the first preset deviation value; When the time when the first current deviation value is less than the second preset deviation value reaches a fifth preset time, control the compressor to stop oil return.

4. The air conditioning system of claim 1, wherein, The step of controlling the compressor to return oil specifically comprises: Control the compressor to operate at a preset frequency, and the preset frequency is within the rated frequency interval.

5. A control method of an air conditioning system, characterized by, The air conditioning system comprises: an outdoor unit and at least one indoor unit; The outdoor unit comprises: a compressor and a current sensor connected with the compressor; The control method comprises: In response to the start of the compressor, obtain the operating frequency of the compressor; Statistical operating time of the operating frequency outside the rated frequency interval; After the operating time is greater than a first preset time, obtain the first current value flowing through the compressor every interval preset time period; Obtain the discharge pressure and suction pressure of the compressor; According to the corresponding relationship between the pre-stored discharge pressure and suction pressure and the second current value, determine the second current value; The difference between the first current value and the second current value is determined as the first current deviation value; Generate current deviation change rate, the current deviation change rate is the difference between the first current deviation value and the second current deviation value; the second current deviation value is related to the current flowing through the compressor before reading the first current value; If a preset condition is met, it is determined that the compressor is in an oil shortage operation state; The preset condition includes at least one of the following: a time during which the current deviation change rate is greater than a preset threshold value exceeds a second preset time, the first current deviation value is greater than a first preset deviation value, and the operation time is greater than a third preset time; When the compressor is in the oil shortage operation state, the compressor is controlled to start oil return.

6. The control method according to claim 5, characterized by After the step of controlling the compressor to start oil return, the control method further includes: A time during which the first current deviation value is less than a second preset deviation value is counted, the second preset deviation value being less than the first preset deviation value; When the time during which the first current deviation value is less than the second preset deviation value reaches a fifth preset time, the compressor is controlled to stop oil return.

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