An air conditioner and a compressor oil return control method of the air conditioner

Abstract

The application discloses an air conditioner and a compressor oil return control method thereof. After the air conditioner is started and runs for a preset first time length, the current bottom temperature of the compressor, the current working temperature corresponding to the current working mode, the current running frequency of the compressor and the current outdoor temperature are obtained; the current working temperature is the current condensing temperature or the current evaporating temperature; the temperature difference between the current working temperature and the current bottom temperature is calculated; when the temperature difference, the current running frequency and the current outdoor temperature satisfy the oil return condition corresponding to the current working mode, the oil return mode is entered. The running conditions of the whole machine can be judged through the calculated temperature difference, the running frequency of the compressor and the outdoor temperature, and after the corresponding conditions are satisfied, the oil return mode is automatically entered, automatic oil return control is realized, the oil return control of the air conditioner is optimized, the effective oil return of the compressor is ensured, and the stable operation of the compressor is ensured.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an air conditioner and a method for controlling the oil return of the air conditioner's compressor. Background Technology

[0002] During the operation of an air conditioner, the refrigerant carries away the lubricating oil in the compressor as it flows through it. When the air conditioner is running at low frequency, the pressure in the refrigerant passage decreases, which reduces the flow rate of the lubricating oil and refrigerant, causing the compressor to fail due to insufficient lubricating oil.

[0003] Current technologies employ a return oil control strategy that detects the compressor's operating frequency and temperature and forces oil return after a period of continuous operation. However, existing forced oil return control strategies lack efficiency and thus affect the stable operation of the compressor. Summary of the Invention

[0004] The purpose of this invention is to provide an air conditioner and an air conditioner compressor oil return control method to ensure effective oil return to the compressor and stable operation of the compressor.

[0005] This invention provides an air conditioner, comprising:

[0006] The refrigerant circuit circulates the refrigerant sequentially through the compressor, condenser, expansion valve, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger.

[0007] A first temperature sensor is used to detect the condensing temperature of the condenser;

[0008] The second temperature sensor is used to detect the evaporation temperature of the evaporator;

[0009] A third temperature sensor is disposed at the bottom of the compressor for detecting the bottom temperature of the compressor;

[0010] The fourth temperature sensor is used to detect the outdoor temperature;

[0011] Controller, used for:

[0012] After the air conditioner has been running for a preset first period of time, the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature are obtained; the current operating temperature is the current condensing temperature or the current evaporating temperature.

[0013] Calculate the temperature difference between the current operating temperature and the current bottom temperature;

[0014] When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, the oil return mode is entered.

[0015] Preferably, the controller is further configured to:

[0016] After entering the oil return mode, the operating frequency of the compressor is adjusted to the first preset value, and the currently operating throttling component is detected;

[0017] When the currently operating throttling component is an electronic expansion valve, the corresponding opening degree is matched according to the current operating parameters of the air conditioner, and the electronic expansion valve is adjusted to the opening degree and operated for a preset second time, and then the oil return mode is exited.

[0018] When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the second duration before exiting the oil return mode.

[0019] As a preferred embodiment, the controller is further configured to:

[0020] When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature;

[0021] When the temperature difference is within a preset first range, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated.

[0022] When the recalculated temperature difference is still within the first interval, the current outdoor temperature is within the preset second interval, and the current operating frequency is not greater than the preset first threshold frequency, the air conditioner is controlled to enter the oil return mode.

[0023] Preferably, the controller is further configured to:

[0024] When the temperature difference is within a preset third range, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated.

[0025] When the recalculated temperature difference is still within the third interval, and the current outdoor temperature is within the preset fourth interval, and the current operating frequency is not greater than the first threshold frequency, the air conditioner is controlled to enter the oil return mode.

[0026] The third interval is within the range of the first interval, and the second interval and the fourth interval have no intersection.

[0027] As a preferred embodiment, the controller is further configured to:

[0028] When the air conditioner is operating in heating mode, the current evaporation temperature of the evaporator is obtained as the current operating temperature;

[0029] When the temperature difference is within the preset fifth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset fourth time interval, and the temperature difference is recalculated.

[0030] When the recalculated temperature difference is still within the fifth interval, and the current outdoor temperature is within the preset sixth interval, and the current operating frequency is not greater than the preset second threshold frequency, the air conditioner is controlled to enter the oil return mode.

[0031] As an improvement to the above solution, the controller is also used for:

[0032] When the temperature difference is within the preset seventh interval, the current bottom temperature and the current evaporation temperature are reacquired after the fourth time interval, and the temperature difference is recalculated.

[0033] If the recalculated temperature difference is still within the seventh interval, the current outdoor temperature is within the preset eighth interval, and the current operating frequency is not greater than the second threshold frequency, the air conditioner is controlled to enter the oil return mode.

[0034] When the temperature difference is within the preset ninth interval, the current bottom temperature and the current evaporation temperature are reacquired after the fourth time interval, and the temperature difference is recalculated.

[0035] If the recalculated temperature difference is still within the ninth interval, the current outdoor temperature is within the preset tenth interval, and the current operating frequency is not greater than the second threshold frequency, the air conditioner is controlled to enter the oil return mode.

[0036] The seventh interval is within the range of the fifth interval, the ninth interval is within the range of the seventh interval, and the sixth interval, the tenth interval, and the eighth interval have no overlap.

[0037] Preferably, the controller is further configured to:

[0038] When the temperature difference meets the anti-liquid compression condition corresponding to the current working mode, the anti-liquid compression mode is entered.

[0039] Adjust the operating frequency of the compressor to the highest frequency of the current working mode, and detect the throttling component currently in operation;

[0040] When the currently operating throttling component is an electronic expansion valve, after adjusting the electronic expansion valve to the minimum opening and running for a preset fifth time, the anti-liquid compression mode is exited.

[0041] When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the fifth time period before exiting the anti-liquid compression mode.

[0042] Furthermore, the air conditioner also includes:

[0043] The fifth temperature sensor is used to detect the indoor temperature;

[0044] The controller is also used for:

[0045] When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature;

[0046] When the temperature difference is within the preset eleventh interval, the current bottom temperature and the current condensation temperature are reacquired after a preset sixth time interval, and the temperature difference is recalculated.

[0047] When the recalculated temperature difference is still within the eleventh interval, the liquid-resistant compression mode is entered.

[0048] After entering the anti-liquid compression mode, the current indoor temperature is detected;

[0049] When the difference between the detected current indoor temperature and the set operating temperature is not less than the preset first compensation temperature, the air conditioner is controlled to stop operating. After a preset seventh time interval, the anti-liquid compression mode is exited and the operating parameters of the air conditioner are restored.

[0050] Furthermore, the air conditioner also includes:

[0051] The fifth temperature sensor is used to detect the indoor temperature;

[0052] The controller is also used for:

[0053] When the air conditioner is operating in heating mode, the current evaporation temperature of the condenser is obtained as the current operating temperature;

[0054] When the temperature difference is within the preset twelfth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset seventh time interval, and the temperature difference is recalculated.

[0055] When the recalculated temperature difference is still within the twelfth interval, the liquid-resistant compression mode is entered.

[0056] After entering the anti-liquid compression mode, the current indoor temperature is detected;

[0057] When the difference between the detected current indoor temperature and the set operating temperature is not greater than the preset second compensation temperature, the air conditioner is controlled to stop operating. After a preset eighth time interval, the anti-liquid compression mode is exited, and the operating parameters of the air conditioner are restored.

[0058] This invention also provides a method for controlling the oil return of an air conditioner compressor, the air conditioner comprising:

[0059] The refrigerant circuit circulates the refrigerant sequentially through the compressor, condenser, expansion valve, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger.

[0060] A first temperature sensor is used to detect the condensing temperature of the condenser;

[0061] The second temperature sensor is used to detect the evaporation temperature of the evaporator;

[0062] A third temperature sensor is disposed at the bottom of the compressor for detecting the bottom temperature of the compressor;

[0063] The fourth temperature sensor is used to detect the outdoor temperature;

[0064] The method includes:

[0065] After the air conditioner has been running for a preset first period of time, the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature are obtained; the current operating temperature is the current condensing temperature or the current evaporating temperature.

[0066] Calculate the temperature difference between the current operating temperature and the current bottom temperature;

[0067] When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, the oil return mode is entered.

[0068] Compared with existing technologies, the air conditioner and its compressor oil return control method disclosed in this invention, after the air conditioner has been running for a preset first period of time, acquires the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature; the current operating temperature is either the current condensing temperature or the current evaporating temperature; calculates the temperature difference between the current operating temperature and the current bottom temperature; and enters the oil return mode when the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current operating mode. By calculating the temperature difference, compressor operating frequency, and outdoor temperature, the overall operating conditions of the unit can be determined. Upon meeting the corresponding conditions, the unit automatically enters the oil return mode, achieving automatic oil return control, optimizing the oil return control of the air conditioner, ensuring effective oil return to the compressor, and guaranteeing stable compressor operation. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the structure of an air conditioner according to one embodiment of the present invention;

[0070] Figure 2 This is a partial structural schematic diagram of the refrigerant circuit of the air conditioner in an embodiment of the present invention;

[0071] Figure 3 This is a partial structural schematic diagram of the air conditioner in another embodiment of the present invention;

[0072] Figure 4 This is a schematic diagram of the condenser provided in an embodiment of the present invention;

[0073] Figure 5 This is a schematic diagram of the structure of the evaporator provided in an embodiment of the present invention;

[0074] Figure 6 This is a schematic diagram of the compressor provided in an embodiment of the present invention;

[0075] Figure 7 This is a schematic diagram of the outdoor unit provided in an embodiment of the present invention;

[0076] Figure 8 A flowchart illustrating the work performed by the controller in the first embodiment of the present invention;

[0077] Figure 9 This is a flowchart illustrating the work performed by the controller in the second implementation of this invention.

[0078] Figure 10 This is a flowchart illustrating the work performed by the controller in the third implementation of this invention.

[0079] Figure 11 This is a flowchart illustrating the work performed by the controller in the fourth implementation of this invention.

[0080] Figure 12 This is a flowchart illustrating the work performed by the controller in the fifth implementation method of this invention.

[0081] Figure 13 This is a structural schematic diagram of an indoor unit provided in an embodiment of the present invention. Detailed Implementation

[0082] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0083] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0084] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. 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.

[0085] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0086] See Figure 1This is a schematic diagram of the structure of an air conditioner according to one embodiment of the present invention. The present invention provides an air conditioner 100, including an indoor unit 110 and an outdoor unit 120. The indoor unit 110 is typically installed indoors and can be in the form of a wall-mounted unit, a floor-standing unit, etc. The outdoor unit 120 is typically installed outdoors and is used for heat exchange with the indoor environment. The air conditioner 100 has a refrigerant circuit 130. By circulating the refrigerant in the refrigerant circuit 130, a vapor compression refrigeration cycle can be performed. Connecting pipes are used to connect the indoor unit 110 and the outdoor unit 120 to form a refrigerant circuit for refrigerant circulation.

[0087] See Figure 2 This is a partial structural diagram of the refrigerant circuit of an air conditioner in an embodiment of the present invention. In this application, the air conditioner executes a refrigeration cycle using a compressor 131, an indoor heat exchanger 132, an expansion valve 133, and an outdoor heat exchanger 134. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation, supplying refrigerant to conditioned and heat-exchanged air. The indoor heat exchanger 132 is typically located in the indoor unit 110, while the compressor 131 and outdoor heat exchanger 134 are typically located in the outdoor unit 120. The expansion valve 133 can be located in either the indoor unit 110 or the outdoor unit 120. The indoor heat exchanger 132 and outdoor heat exchanger 134 function as condensers or evaporators. When the indoor heat exchanger 132 functions as a condenser, the air conditioner acts as a heater in heating mode; when the indoor heat exchanger 132 functions as an evaporator, the air conditioner acts as a cooler in cooling mode.

[0088] Compressor 131 compresses refrigerant gas at high temperature and pressure and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and heat is released to the surrounding environment through the condensation process. Expansion valve 133 causes the high-temperature, high-pressure liquid refrigerant condensed in the condenser to expand into a low-pressure liquid refrigerant. The evaporator evaporates the refrigerant that has expanded in expansion valve 133 and returns the low-temperature, low-pressure refrigerant gas to compressor 131. The evaporator achieves a cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0089] See Figure 3 This is a partial structural diagram of an air conditioner in another embodiment of the present invention. The air conditioner includes a refrigerant circuit 130, a first temperature sensor 101, a second temperature sensor 102, a third temperature sensor 103, and a fourth temperature sensor 104.

[0090] See Figure 4This is a schematic diagram of the structure of the condenser provided in an embodiment of the present invention; the flow path of the condenser includes 8 bends, wherein a first temperature sensor 101 is provided at the bend position in the middle of the condenser, generally at the 4th or 5th bend position, for accurately detecting the condensing temperature of the condenser.

[0091] See Figure 5 This is a schematic diagram of the evaporator provided in an embodiment of the present invention; a second temperature sensor 102 is provided in the middle of the evaporator, which is generally located at the 5th or 6th bend in the evaporator flow path, and is used to accurately detect the evaporation temperature of the evaporator.

[0092] See Figure 6 This is a schematic diagram of the compressor provided in an embodiment of the present invention; a third temperature sensor 103 is provided at the bottom of the compressor, which is generally located in the body part below the return gas position of the compressor body, and is used to accurately detect the bottom temperature of the compressor.

[0093] See Figure 7 This is a schematic diagram of the outdoor unit provided in an embodiment of the present invention. The outdoor unit is equipped with a fourth temperature sensor 104, which is generally located on the upper left of the condenser at the return air position. Simultaneously, considering the heat radiation from the condenser, the sensor should be at least 5mm away from the condenser to accurately detect the outdoor temperature.

[0094] Furthermore, the air conditioner 100 also includes a controller 140, which has an outdoor control device built into the outdoor unit 120 and an indoor control device built into the indoor unit 110. The outdoor control device and the indoor control device are configured to be connected to each other by signal lines and can send / receive signals to each other, thereby realizing operations such as information acquisition and control command issuance for various components of the air conditioner.

[0095] In an embodiment of the present invention, see Figure 8 This is a flowchart illustrating the operation performed by the controller in the first embodiment of the present invention. The controller 140 is able to respond to a preset oil return control command and complete the oil return control operation of the air conditioner, specifically including steps S11 to S13:

[0096] S11. After the air conditioner has been running for a preset first period of time, acquire the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature; the current operating temperature is the current condensing temperature or the current evaporating temperature.

[0097] S12. Calculate the temperature difference between the current operating temperature and the current bottom temperature;

[0098] S13. When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, enter the oil return mode.

[0099] In this embodiment of the invention, after the air conditioner has been running for a preset first period of time, the current bottom temperature T of the compressor is obtained by a third temperature sensor. y The current operating temperature T is obtained through the first temperature sensor or the second temperature sensor. 工 The compressor's operating frequency f and the current outdoor temperature T obtained through the fourth temperature sensor. o ;

[0100] The current operating temperature refers to the device operating under the corresponding load in the current air conditioning operating mode. When the air conditioner is running in cooling mode, dehumidification mode, or heating mode, the corresponding current condensing temperature or current evaporation temperature is obtained as the current operating temperature.

[0101] Calculate the current operating temperature T 工 With the current bottom temperature T y The temperature difference ΔT, ΔT = T 工 -T y ;

[0102] The system intelligently determines whether the compressor is in liquid compression mode based on the temperature difference, protecting the compressor's operation. It also assesses the overall operating environment of the air conditioner by considering the current operating frequency and outdoor temperature, determining whether oil return control is necessary. When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current operating mode, the compressor needs to return oil and enter oil return mode.

[0103] By calculating the temperature difference, compressor operating frequency, and outdoor temperature, the operating conditions of the entire unit can be determined. Once the corresponding conditions are met, the unit automatically enters the oil return mode to achieve automatic oil return control, optimize the oil return control of the air conditioner, ensure effective oil return to the compressor, and guarantee the stable operation of the compressor.

[0104] In yet another embodiment of the present invention, the controller is further configured to:

[0105] After entering the oil return mode, the operating frequency of the compressor is adjusted to the first preset value, and the currently operating throttling component is detected;

[0106] When the currently operating throttling component is an electronic expansion valve, the corresponding opening degree is matched according to the current operating parameters of the air conditioner, and the electronic expansion valve is adjusted to the opening degree and operated for a preset second time, and then the oil return mode is exited.

[0107] When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the second duration before exiting the oil return mode.

[0108] In the specific implementation of this embodiment, please refer to Figure 9 This is a flowchart illustrating the operation performed by the controller in the second implementation of this invention. After entering the oil return mode, the controller performs corresponding oil return control, specifically executing the following steps:

[0109] Step S901: Adjust the operating frequency of the compressor to 50Hz;

[0110] It should be noted that in this embodiment, the first preset value is 50Hz, which facilitates the oil return of the compressor; in other embodiments, the operating frequency of the compressor can also be set and adjusted according to the actual situation, and no specific limitation is made here.

[0111] Step S902: Detect the currently operating throttling component.

[0112] Step S903: Determine whether the currently operating throttling component is an electronic expansion valve.

[0113] If so, proceed to step S904.

[0114] If not, proceed to step S906.

[0115] Step S904: Match the corresponding opening degree according to the current operating parameters, that is, match the corresponding opening degree according to the cooling capacity / dehumidification capacity / heating mode corresponding to the current operating parameters.

[0116] Step S905: Adjust the electronic expansion valve to the specified opening degree, run for 10 minutes, and then proceed to step S907.

[0117] Step S906: Maintain the current operating parameters of the air conditioner for 10 minutes. That is, when the currently operating throttling component is a capillary tube or a throttling valve, maintain the current operating parameters of the air conditioner for 10 minutes.

[0118] It should be noted that in this embodiment, the specific control process of the oil return mode is illustrated by taking the second duration of 10 minutes as an example. In other embodiments, the settings and adjustments can be made according to the actual situation, and no specific limitations are made here.

[0119] Step S907: Exit the oil return mode. Restore the air conditioner to its original operating mode and corresponding operating parameters.

[0120] It should be noted that the control process of the oil return mode proposed in this embodiment is a preferred implementation. In other embodiments, the specific control process of the oil return mode can adopt other existing control methods, which are not specifically limited here.

[0121] By adjusting the oil return mode control process and adaptively adjusting the opening of the electronic expansion valve, a throttling component, efficient oil return of the compressor can be achieved.

[0122] For a preferred embodiment, see Figure 10 This is a flowchart illustrating the work performed by the controller in the third implementation of the present invention. The present invention is a further implementation based on the above embodiments. The working modes of the air conditioner include dehumidification mode and cooling mode.

[0123] In step S11, when the air conditioner is running in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature.

[0124] Step S13 includes the following steps:

[0125] Step S131: When the temperature difference is within a preset first interval, after a preset third time interval, the current bottom temperature and the current condensation temperature are reacquired, and the temperature difference is recalculated.

[0126] Step S132: When the recalculated temperature difference is still within the first interval, and the current outdoor temperature is within the preset second interval, and the current operating frequency is not greater than the preset first threshold frequency, control the air conditioner to enter the oil return mode.

[0127] In this embodiment of the invention, after the air conditioner enters the cooling mode and then the dehumidification mode, it runs for a preset third time period, which can be determined according to the cooling capacity of the machine.

[0128] Get the current bottom temperature T of the compressor y and the current condensing temperature T of the condenser w Calculate the temperature difference ΔT, ΔT = T w -T y ;

[0129] When 0℃ < ΔT < 3℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current condensing temperature T of the condenser w Then, recalculate the temperature difference ΔT.

[0130] When the condition 0℃<△T<3℃ still holds true, the current outdoor ambient temperature T is measured. O And the compressor's current operating frequency f, when 16℃≤TO When the temperature is <21℃ and the compressor operating frequency f≤30Hz, the compressor meets the preset conditions for entering the oil return mode under the refrigeration / dehumidification mode, and the compressor is controlled to enter the oil return mode.

[0131] It should be noted that in this embodiment, the first interval, the second interval, and the first threshold frequency are all preferred values, but are not limited to the only values. In other embodiments, the first interval, the second interval, and the first threshold frequency can be adjusted or controlled according to the actual situation, and are not limited here.

[0132] By detecting the condenser temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in cooling or dehumidification mode, thereby achieving accurate control of oil return and avoiding false triggering.

[0133] As an improvement to the above embodiment, in step S11, when the air conditioner is running in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature.

[0134] Then step S13 also includes the following steps:

[0135] Step S133: When the temperature difference is within a preset third interval, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated.

[0136] Step S134: When the recalculated temperature difference is still within the third interval, and the current outdoor temperature is within the preset fourth interval, and the current operating frequency is not greater than the first threshold frequency, control the air conditioner to enter the oil return mode.

[0137] The third interval is within the range of the first interval, and the second interval and the fourth interval have no intersection.

[0138] In the specific implementation of this embodiment, after the air conditioner enters the cooling mode or dehumidification mode, it runs for a preset third time period, which can be determined according to the cooling capacity of the machine.

[0139] Get the current bottom temperature T of the compressor y and the current condensing temperature T of the condenser w Calculate the temperature difference ΔT, ΔT = T w -T y ;

[0140] When 0℃ < ΔT < 1℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current condensing temperature T of the condenser w Then, recalculate the temperature difference ΔT.

[0141] When the condition 0℃<△T<1℃ still holds true, the current outdoor ambient temperature T is measured. O and the compressor's current operating frequency f, when T O When the temperature is ≥21℃ and the compressor operating frequency f≤30Hz, the compressor meets the preset conditions for entering the oil return mode in the cooling / dehumidification mode, and the compressor is controlled to enter the oil return mode.

[0142] It should be noted that in this embodiment, the third interval and the fourth interval are preferred values, but are not limited to the only values. In other embodiments, the third interval and the fourth interval can be adjusted or controlled according to the actual situation. It is necessary to satisfy that the third interval is within the range of the first interval and the second interval and the fourth interval have no intersection. This is not limited here.

[0143] By detecting the condenser temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in cooling or dehumidification mode, thereby achieving accurate control of oil return and avoiding false triggering.

[0144] In yet another embodiment provided by the present invention, as a preferred implementation, see [link to previous document]. Figure 11 This is a flowchart illustrating the work performed by the controller in the fourth implementation of this invention. This invention is a further implementation based on the above embodiments, and the working mode of the air conditioner includes a heating mode.

[0145] In step S11, when the air conditioner is running in heating mode, the current evaporation temperature of the condenser is obtained as the current operating temperature.

[0146] Step S13 includes the following steps:

[0147] Step S135: When the temperature difference is within the preset fifth interval, after a preset fourth time interval, the current bottom temperature and the current evaporation temperature are reacquired, and the temperature difference is recalculated.

[0148] Step S136: When the recalculated temperature difference is still within the fifth interval, the current outdoor temperature is within the preset sixth interval, and the current operating frequency is not greater than the preset second threshold frequency, control the air conditioner to enter the oil return mode.

[0149] In this embodiment of the invention, after the air conditioner enters the heating mode, it runs for a preset fourth duration, which can be determined according to the machine's heating capacity.

[0150] Get the current bottom temperature T of the compressor y and the current evaporation temperature T of the evaporator nCalculate the temperature difference ΔT, ΔT = T n -T y ;

[0151] When 0℃ < ΔT < 3℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current evaporation temperature T of the evaporator n Then, recalculate the temperature difference ΔT.

[0152] When the condition 0℃<△T<3℃ still holds true, the current outdoor ambient temperature T is measured. O And the compressor's current operating frequency f, when -1℃≤T O When the temperature is <5℃ and the compressor operating frequency f≤40Hz, the compressor meets the preset conditions for entering the oil return mode in the heating mode, and the compressor is controlled to enter the oil return mode.

[0153] It should be noted that in this embodiment, the fifth interval, the sixth interval, and the second threshold frequency are all preferred values, but are not limited to the only values. In other embodiments, the fifth interval, the sixth interval, and the second threshold frequency can be adjusted or controlled according to the actual situation, and are not limited here.

[0154] By detecting the evaporator temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in heating mode, thereby achieving accurate control of oil return and avoiding false triggering.

[0155] As an improvement to the above embodiment, in step S11, when the air conditioner is running in heating mode, the current evaporation temperature of the evaporator is obtained as the current operating temperature.

[0156] Then step S13 also includes the following steps:

[0157] Step S137: When the temperature difference is within the preset seventh interval, after the fourth time interval, the current bottom temperature and the current evaporation temperature are reacquired, and the temperature difference is recalculated.

[0158] Step S138: When the recalculated temperature difference is still within the seventh interval, the current outdoor temperature is within the preset eighth interval, and the current operating frequency is not greater than the second threshold frequency, control the air conditioner to enter the oil return mode.

[0159] The seventh interval is within the range of the fifth interval, and the sixth interval has no intersection with the eighth interval.

[0160] In the specific implementation of this embodiment, after the air conditioner enters the heating mode, it runs for a preset fourth duration, which can be determined according to the machine's heating capacity.

[0161] Get the current bottom temperature T of the compressor y and the current evaporation temperature T of the evaporator n Calculate the temperature difference ΔT, ΔT = T n -T y ;

[0162] When 0℃ < ΔT < 2℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current evaporation temperature T of the evaporator n Then, recalculate the temperature difference ΔT.

[0163] When the condition 0℃<△T<2℃ still holds true, the current outdoor ambient temperature T is measured. O and the compressor's current operating frequency f, when T O When the temperature is less than -1℃ and the compressor operating frequency f ≤ 40Hz, the compressor meets the preset conditions for entering the oil return mode in the heating mode, and the compressor is controlled to enter the oil return mode.

[0164] It should be noted that in this embodiment, the seventh interval and the eighth interval are preferred values, but are not limited to the only values. In other embodiments, the seventh interval and the eighth interval can be adjusted or controlled according to the actual situation. It is necessary to satisfy that the seventh interval is within the range of the fifth interval, and the sixth interval and the eighth interval have no intersection. This is not limited here.

[0165] By detecting the condenser temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in heating mode, thereby achieving accurate control of oil return and avoiding false triggering.

[0166] As an improvement to the above embodiment, in step S11, when the air conditioner is running in heating mode, the current evaporation temperature of the evaporator is obtained as the current operating temperature.

[0167] Then step S13 also includes the following steps:

[0168] Step S139: When the temperature difference is within the preset ninth interval, after the fourth time interval, the current bottom temperature and the current evaporation temperature are reacquired, and the temperature difference is recalculated.

[0169] Step S1310: When the recalculated temperature difference is still within the ninth interval, the current outdoor temperature is within the preset tenth interval, and the current operating frequency is not greater than the second threshold frequency, control the air conditioner to enter the oil return mode.

[0170] The ninth interval is within the range of the seventh interval, and the sixth interval, the tenth interval, and the eighth interval have no intersection.

[0171] In the specific implementation of this embodiment, after the air conditioner enters the heating mode, it runs for a preset fourth duration, which can be determined according to the machine's heating capacity.

[0172] Get the current bottom temperature T of the compressor y and the current evaporation temperature T of the evaporator n Calculate the temperature difference ΔT, ΔT = T n -T y ;

[0173] When 0℃ < ΔT < 1℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current evaporation temperature T of the evaporator n Then, recalculate the temperature difference ΔT.

[0174] When the condition 0℃<△T<1℃ still holds true, the current outdoor ambient temperature T is measured. O and the compressor's current operating frequency f, when T O When the temperature is ≥5℃ and the compressor operating frequency f≤40Hz, the compressor meets the preset conditions for entering the oil return mode in the heating mode, and the compressor is controlled to enter the oil return mode.

[0175] It should be noted that in this embodiment, the ninth interval and the tenth interval are preferred values, but are not limited to the only values. In other embodiments, the ninth interval and the tenth interval can be adjusted or controlled according to the actual situation. It is necessary to satisfy that the ninth interval is within the range of the seventh interval, and the sixth interval, the tenth interval and the eighth interval have no intersection. This is not limited here.

[0176] By detecting the condenser temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in heating mode, thereby achieving accurate control of oil return and avoiding false triggering.

[0177] In yet another embodiment of the present invention, the controller is further configured to:

[0178] When the temperature difference meets the anti-liquid compression condition corresponding to the current working mode, the anti-liquid compression mode is entered.

[0179] Adjust the operating frequency of the compressor to the highest frequency of the current working mode, and detect the throttling component currently in operation;

[0180] When the currently operating throttling component is an electronic expansion valve, after adjusting the electronic expansion valve to the minimum opening and running for a preset fifth time, the anti-liquid compression mode is exited.

[0181] When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the fifth time period before exiting the anti-liquid compression mode.

[0182] In the specific implementation of this embodiment, please refer to Figure 12 This is a flowchart illustrating the operation of the controller in the fifth implementation of this invention. The controller is further configured to perform the following steps:

[0183] Step S1201: Obtain the current bottom temperature T of the compressor. y and the current operating temperature T 工 ;

[0184] Step S1202: Calculate the current temperature difference, and calculate the temperature difference ΔT, where ΔT = T 工 -T y ;

[0185] Step S1203: Determine whether △T satisfies the anti-liquid compression condition corresponding to the current working mode;

[0186] If not, return to step S1202;

[0187] If so, proceed to step S1204. When the temperature difference meets the anti-liquid compression condition corresponding to the current working mode, enter the anti-liquid compression mode.

[0188] Step S1204: Adjust the operating frequency of the compressor to the highest frequency; that is, after entering the anti-liquid compression mode, adjust the operating frequency of the compressor to the highest frequency of the current working mode. Different working modes correspond to different highest frequencies. That is, when the compressor is running in cooling mode, heating mode or dehumidification mode, different highest frequencies are matched for compressor control.

[0189] Step S1205: Detect the currently operating throttling component;

[0190] Step S1206: Determine whether the currently operating throttling component is an electronic expansion valve.

[0191] If so, proceed to step S1207.

[0192] If not, proceed to step S1208.

[0193] Step S1207: Adjust the electronic expansion valve to the minimum opening degree and run for 3 minutes, then proceed to step S1209.

[0194] Step S1208: Maintain the current operating parameters of the air conditioner for 3 minutes. That is, when the currently operating throttling component is a capillary tube or a throttling valve, maintain the current operating parameters of the air conditioner.

[0195] It should be noted that in this embodiment, the fifth duration of 3 minutes is used as an example to illustrate the specific control process of the oil return mode. In other embodiments, the settings and adjustments can be made according to the actual situation, and no specific limitations are made here.

[0196] Step S1209: Exit the anti-liquid compression mode. Restore the air conditioner to its original operating mode and corresponding operating parameters.

[0197] It should be noted that the control process of the anti-liquid compression mode proposed in this embodiment is a preferred implementation. In other embodiments, the specific control process of the anti-liquid compression mode can adopt other existing control methods, which are not specifically limited here.

[0198] By adjusting the anti-liquid compression mode control process and adaptively adjusting the opening of the electronic expansion valve, the refrigerant charge can be prevented from being compressed within the agreed range, thus avoiding compressor wear and damage and affecting its use.

[0199] In another embodiment provided by the present invention, the air conditioner further includes:

[0200] The fifth temperature sensor is used to detect the indoor temperature;

[0201] The controller is also used for:

[0202] When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature;

[0203] When the temperature difference is within the preset eleventh interval, the current bottom temperature and the current condensation temperature are reacquired after a preset sixth time interval, and the temperature difference is recalculated.

[0204] When the recalculated temperature difference is still within the eleventh interval, the liquid-resistant compression mode is entered.

[0205] After entering the anti-liquid compression mode, the current indoor temperature is detected;

[0206] When the difference between the detected current indoor temperature and the set operating temperature is not less than the preset first compensation temperature, the air conditioner is controlled to stop operating. After a preset seventh time interval, the anti-liquid compression mode is exited and the operating parameters of the air conditioner are restored.

[0207] In the specific implementation of this embodiment, please refer to Figure 13 This is a schematic diagram of an indoor unit provided in an embodiment of the present invention. The indoor unit is equipped with a fifth temperature sensor 105 for detecting the indoor temperature.

[0208] Generally, it is located at the lower right of the evaporator for easy installation. The fifth temperature sensor is placed at the return air position to detect the real-time ambient temperature. At the same time, the cold radiation of the evaporator should be taken into account, and the distance from the evaporator should be more than 5mm.

[0209] After the air conditioner enters cooling or dehumidification mode, obtain the current bottom temperature T of the compressor. y and the current condensing temperature T of the condenser w Calculate the temperature difference ΔT, ΔT = T w -T y ;

[0210] When ΔT≤0℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current condensing temperature T of the condenser w Then, recalculate the temperature difference ΔT.

[0211] When △T≤0℃ still holds true, the compressor meets the preset conditions for entering the anti-liquid compression mode under the refrigeration / dehumidification mode, and the compressor is then controlled to enter the anti-liquid compression mode.

[0212] By detecting the condenser temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in cooling or dehumidification mode, thereby achieving accurate control against liquid compression and avoiding false triggering.

[0213] After entering the anti-liquid compression mode, the current indoor temperature T is detected. I And obtain the operating temperature T of the air conditioner used for setting. S ;

[0214] Calculate the current indoor temperature T I With operating temperature T S The difference Δt;

[0215] When the difference Δt is not less than the preset first compensation temperature, the air conditioner is controlled to stop running. After 3 minutes, the anti-liquid compression mode is exited, the air conditioner is restored to cooling mode / initial mode, and the operating parameters of the air conditioner are restored.

[0216] It should be noted that in this embodiment, the eleventh interval and the first compensation temperature are preferred values, but not the only values. In other embodiments, the eleventh interval and the first compensation temperature can be adjusted or controlled according to the actual situation, and are not limited here.

[0217] When the air conditioner enters the anti-liquid compression mode from either cooling or dehumidification mode, it detects the indoor temperature. If the indoor temperature is too low, the air conditioner stops operating to prevent the air conditioner from running too cold in the anti-liquid compression mode, which could cause discomfort to the user.

[0218] In another embodiment provided by the present invention, the air conditioner further includes:

[0219] The fifth temperature sensor is used to detect the indoor temperature;

[0220] The controller is also used for:

[0221] When the air conditioner is operating in heating mode, the current evaporation temperature of the condenser is obtained as the current operating temperature;

[0222] When the temperature difference is within the preset twelfth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset seventh time interval, and the temperature difference is recalculated.

[0223] When the recalculated temperature difference is still within the twelfth interval, the liquid-resistant compression mode is entered.

[0224] After entering the anti-liquid compression mode, the current indoor temperature is detected;

[0225] When the difference between the detected current indoor temperature and the set operating temperature is not greater than the preset second compensation temperature, the air conditioner is controlled to stop operating. After a preset eighth time interval, the anti-liquid compression mode is exited, and the operating parameters of the air conditioner are restored.

[0226] In this specific implementation, after the air conditioner enters the heating mode, the current bottom temperature T of the compressor is obtained. y and the current evaporation temperature T of the evaporator n Calculate the temperature difference ΔT, ΔT = T n -T y ;

[0227] When ΔT≤0℃, the current bottom temperature T of the compressor is reacquired after a 2-minute interval. y and the current evaporation temperature T of the evaporator n Then, recalculate the temperature difference ΔT.

[0228] When △T≤0℃ still holds true, the compressor meets the preset conditions for entering the anti-liquid compression mode in heating mode, and the compressor is then controlled to enter the anti-liquid compression mode.

[0229] By detecting the evaporator temperature and compressor temperature of the air conditioner twice consecutively, it is possible to accurately determine whether the compressor is in liquid compression mode in heating mode, thereby achieving accurate control against liquid compression and avoiding false triggering.

[0230] After entering the anti-liquid compression mode, the current indoor temperature T is detected. I And obtain the operating temperature T of the air conditioner used for setting. S ;

[0231] Calculate the current indoor temperature T I With operating temperature T S The difference Δt;

[0232] When the difference Δt is not greater than the preset second compensation temperature, the air conditioner is controlled to stop running. After 3 minutes, the anti-liquid compression mode is exited, the air conditioner is restored to cooling mode / initial mode, and the operating parameters of the air conditioner are restored.

[0233] It should be noted that, in this embodiment, the twelfth interval and the second compensation temperature are preferred values, but not the only values. In other embodiments, the twelfth interval and the second compensation temperature can be adjusted or controlled according to the actual situation, and are not limited here.

[0234] When switching from heating mode to anti-liquid compression mode, the air conditioner detects the indoor temperature. If the indoor temperature is too high, the air conditioner stops operating to prevent the air conditioner from running too hot in anti-liquid compression mode, which could cause discomfort to the user.

[0235] This invention also provides a method for controlling the oil return of an air conditioner compressor, the air conditioner comprising:

[0236] The refrigerant circuit circulates the refrigerant sequentially through the compressor, condenser, expansion valve, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger.

[0237] A first temperature sensor is used to detect the condensing temperature of the condenser;

[0238] The second temperature sensor is used to detect the evaporation temperature of the evaporator;

[0239] A third temperature sensor is disposed at the bottom of the compressor for detecting the bottom temperature of the compressor;

[0240] The fourth temperature sensor is used to detect the outdoor temperature;

[0241] The method includes:

[0242] After the air conditioner has been running for a preset first period of time, the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature are obtained; the current operating temperature is the current condensing temperature or the current evaporating temperature.

[0243] Calculate the temperature difference between the current operating temperature and the current bottom temperature;

[0244] When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, the oil return mode is entered.

[0245] The system intelligently determines whether the compressor is in liquid compression mode based on the temperature difference, protecting the compressor's operation. It also assesses the overall operating environment of the air conditioner by considering the current operating frequency and outdoor temperature, determining whether oil return control is necessary. When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current operating mode, the compressor needs to return oil and enter oil return mode.

[0246] By calculating the temperature difference, compressor operating frequency, and outdoor temperature, the operating conditions of the entire unit can be determined. Once the corresponding conditions are met, the unit automatically enters the oil return mode to achieve automatic oil return control, optimize the oil return control of the air conditioner, ensure effective oil return to the compressor, and guarantee the stable operation of the compressor.

[0247] It should be noted that the compressor oil return control method for an air conditioner provided in this embodiment of the invention has the same process steps as the controller of an air conditioner in the above embodiment. The working principles and beneficial effects of the two are one-to-one, so they will not be described again.

[0248] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0249] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An air conditioner, characterized in that, include: The refrigerant circuit circulates the refrigerant sequentially through the compressor, condenser, expansion valve, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. A first temperature sensor is used to detect the condensing temperature of the condenser; The second temperature sensor is used to detect the evaporation temperature of the evaporator; A third temperature sensor is disposed at the bottom of the compressor for detecting the bottom temperature of the compressor; The fourth temperature sensor is used to detect the outdoor temperature; Controller, used for: After the air conditioner has been running for a preset first period of time, the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature are obtained. The current operating temperature is either the current condensation temperature or the current evaporation temperature; Calculate the temperature difference between the current operating temperature and the current bottom temperature; When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, the oil return mode is entered. When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature; When the temperature difference is within a preset first range, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the first interval, and the current outdoor temperature is within the preset second interval, and the current operating frequency is not greater than the preset first threshold frequency, the air conditioner is controlled to enter the oil return mode. When the air conditioner is operating in heating mode, the current evaporation temperature of the evaporator is obtained as the current operating temperature; When the temperature difference is within the preset fifth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset fourth time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the fifth interval, and the current outdoor temperature is within the preset sixth interval, and the current operating frequency is not greater than the preset second threshold frequency, the air conditioner is controlled to enter the oil return mode.

2. The air conditioner as described in claim 1, characterized in that, The controller is also used for: After entering the oil return mode, the operating frequency of the compressor is adjusted to the first preset value, and the currently operating throttling component is detected; When the currently operating throttling component is an electronic expansion valve, the corresponding opening degree is matched according to the current operating parameters of the air conditioner, and the electronic expansion valve is adjusted to the opening degree and operated for a preset second time, and then the oil return mode is exited. When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the second duration before exiting the oil return mode.

3. The air conditioner as described in claim 1, characterized in that, The controller is also used for: When the temperature difference is within a preset third range, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the third interval, and the current outdoor temperature is within the preset fourth interval, and the current operating frequency is not greater than the first threshold frequency, the air conditioner is controlled to enter the oil return mode. The third interval is within the range of the first interval, and the second interval and the fourth interval have no intersection.

4. The air conditioner as described in claim 1, characterized in that, The controller is also used for: When the temperature difference is within the preset seventh interval, the current bottom temperature and the current evaporation temperature are reacquired after the fourth time interval, and the temperature difference is recalculated. If the recalculated temperature difference is still within the seventh interval, the current outdoor temperature is within the preset eighth interval, and the current operating frequency is not greater than the second threshold frequency, the air conditioner is controlled to enter the oil return mode. When the temperature difference is within the preset ninth interval, the current bottom temperature and the current evaporation temperature are reacquired after the fourth time interval, and the temperature difference is recalculated. If the recalculated temperature difference is still within the ninth interval, the current outdoor temperature is within the preset tenth interval, and the current operating frequency is not greater than the second threshold frequency, the air conditioner is controlled to enter the oil return mode. The seventh interval is within the range of the fifth interval, the ninth interval is within the range of the seventh interval, and the sixth interval, the tenth interval, and the eighth interval have no intersection.

5. The air conditioner as described in claim 1, characterized in that, The controller is also used for: When the temperature difference meets the anti-liquid compression condition corresponding to the current working mode, the anti-liquid compression mode is entered. Adjust the operating frequency of the compressor to the highest frequency of the current working mode, and detect the throttling component currently in operation; When the currently operating throttling component is an electronic expansion valve, after adjusting the electronic expansion valve to the minimum opening and running for a preset fifth time, the anti-liquid compression mode is exited. When the currently operating throttling component is a capillary tube or a throttling valve, the air conditioner maintains its current operating parameters for the fifth time period before exiting the anti-liquid compression mode.

6. The air conditioner as described in claim 5, characterized in that, The air conditioner also includes: The fifth temperature sensor is used to detect the indoor temperature; The controller is also used for: When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature; When the temperature difference is within the preset eleventh interval, the current bottom temperature and the current condensation temperature are reacquired after a preset sixth time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the eleventh interval, the liquid-resistant compression mode is entered. After entering the anti-liquid compression mode, the current indoor temperature is detected; When the difference between the detected current indoor temperature and the set operating temperature is not less than the preset first compensation temperature, the air conditioner is controlled to stop operating. After a preset seventh time interval, the anti-liquid compression mode is exited, and the operating parameters of the air conditioner are restored.

7. The air conditioner as described in claim 5, characterized in that, The air conditioner also includes: The fifth temperature sensor is used to detect the indoor temperature; The controller is also used for: When the air conditioner is operating in heating mode, the current evaporation temperature of the condenser is obtained as the current operating temperature; When the temperature difference is within the preset twelfth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset seventh time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the twelfth interval, the liquid-resistant compression mode is entered. After entering the anti-liquid compression mode, the current indoor temperature is detected; When the difference between the detected current indoor temperature and the set operating temperature is not greater than the preset second compensation temperature, the air conditioner is controlled to stop operating. After a preset eighth time interval, the anti-liquid compression mode is exited, and the operating parameters of the air conditioner are restored.

8. A method for controlling the oil return of an air conditioner compressor, characterized in that, The air conditioner includes: The refrigerant circuit circulates the refrigerant sequentially through the compressor, condenser, expansion valve, and evaporator. One of the condenser and the evaporator is an outdoor heat exchanger, and the other is an indoor heat exchanger. A first temperature sensor is used to detect the condensing temperature of the condenser; The second temperature sensor is used to detect the evaporation temperature of the evaporator; A third temperature sensor is disposed at the bottom of the compressor for detecting the bottom temperature of the compressor; The fourth temperature sensor is used to detect the outdoor temperature; The method includes: After the air conditioner has been running for a preset first period of time, the current bottom temperature of the compressor, the current operating temperature corresponding to the current operating mode, the current operating frequency of the compressor, and the current outdoor temperature are obtained; the current operating temperature is the current condensing temperature or the current evaporating temperature. Calculate the temperature difference between the current operating temperature and the current bottom temperature; When the temperature difference, the current operating frequency, and the current outdoor temperature meet the oil return conditions corresponding to the current working mode, the oil return mode is entered. When the air conditioner is operating in dehumidification mode or cooling mode, the current condensing temperature of the condenser is obtained as the current operating temperature; When the temperature difference is within a preset first range, the current bottom temperature and the current condensation temperature are reacquired after a preset third time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the first interval, and the current outdoor temperature is within the preset second interval, and the current operating frequency is not greater than the preset first threshold frequency, the air conditioner is controlled to enter the oil return mode. When the air conditioner is operating in heating mode, the current evaporation temperature of the evaporator is obtained as the current operating temperature; When the temperature difference is within the preset fifth interval, the current bottom temperature and the current evaporation temperature are reacquired after a preset fourth time interval, and the temperature difference is recalculated. When the recalculated temperature difference is still within the fifth interval, and the current outdoor temperature is within the preset sixth interval, and the current operating frequency is not greater than the preset second threshold frequency, the air conditioner is controlled to enter the oil return mode.

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