Air conditioner

Abstract

The invention relates to an air conditioner, which belongs to the technical field of air conditioners and comprises an indoor unit, an indoor heat exchanger, an indoor temperature sensor, an outdoor unit, an outdoor heat exchanger, an outdoor temperature sensor, a compressor, a coping temperature sensor and a controller. The controller is configured to enter an oil return mode if the time when the rotating speed of the compressor is lower than the preset rotating speed exceeds the interval time; in the oil return mode, the rotating speed of the compressor is controlled to be increased to the oil return rotating speed, and oil return operation control is stopped after continuous operation reaches the oil return duration time; when the oil return mode is finished, a coping temperature sensor and an outdoor temperature sensor are controlled to obtain a compressor temperature value and an outdoor temperature value respectively; when the difference value between the compressor temperature value and the outdoor temperature value is smaller than the first preset temperature difference, the oil return rotating speed of the next oil return mode is obtained through first logic calculation; and if the difference value between the compressor temperature value and the outdoor temperature value is larger than a second preset temperature difference, the oil return rotating speed of the next oil return mode is obtained through second logic calculation.

Description

Technical Field

[0001] This application relates to the technical field of air conditioners, and particularly to an air conditioner. Background Art

[0002] An air conditioner, i.e., an air regulator, refers to a device that uses artificial means to adjust and control parameters such as the temperature, humidity, and flow rate of the indoor environmental air in a building or structure.

[0003] In the prior art, it often occurs that the minimum cooling capacity of an air conditioner is much greater than the gradually decreasing indoor heat load. Since the operating speed of the compressor is positively correlated with the cooling capacity of the air conditioner. Therefore, the conventional practice of existing air conditioner manufacturers is to lower the lower limit of the operating speed of the air conditioner compressor, so that the minimum cooling capacity of the air conditioner is reduced, and it better matches the indoor heat load.

[0004] However, in the above solution, when the compressor runs at a low speed continuously, most air conditioning systems will trigger an oil return operation. During the oil return operation, the speed of the compressor is increased to the oil return speed and runs for a period of time. By increasing the flow rate of the refrigerant in the air conditioning system, the lubricating oil remaining in the heat exchanger and pipeline is returned to the compressor. When the speed of the compressor increases during the oil return operation, correspondingly, the heat generation of the compressor becomes larger, the heat dissipation becomes smaller, the bottom superheat is increased, and the oil viscosity is also increased, which improves the reliability of the compressor to a certain extent. However, the conventional oil return control parameters of the air conditioning system are all set to fixed values and cannot be adjusted according to the operating conditions of the air conditioner. If the oil return control cannot ensure the bottom superheat lower limit of the compressor, the compressor will be severely worn and cause air conditioner failures; if too much cooling capacity is generated during the oil return control and the indoor temperature drops too much, it is easy to cause the phenomenon of stopping when the set temperature is reached, and the user experience is poor. Summary of the Invention

[0005] The present invention solves at least one of the technical problems in the related art to some extent.

[0006] Therefore, this application aims to provide an air conditioner. In the oil return mode, it is divided into multiple situations according to the relationship between the difference between the compressor temperature value and the outdoor temperature value and the first preset temperature difference, and the oil return speed is adjusted for different situations to achieve stable operation of the oil return mode and avoid frequent start and stop of the compressor, improving the user experience while ensuring the reliability of the compressor.

[0007] To achieve the above object, the present invention provides an air conditioner, including: An indoor unit; An indoor heat exchanger, which is arranged in the indoor unit; An indoor temperature sensor, which is used to detect the indoor temperature and obtain the indoor temperature value; An outdoor unit; Outdoor heat exchanger, the outdoor heat exchanger is disposed within the outdoor unit, and the outdoor heat exchanger is in communication with the indoor heat exchanger; Outdoor temperature sensor, the outdoor temperature sensor is configured to detect the outdoor temperature and obtain an outdoor temperature value; Compressor, the compressor is disposed within the outdoor unit, and the compressor is configured to deliver refrigerant to the outdoor heat exchanger and the indoor heat exchanger; Top temperature sensor, the top temperature sensor is configured to detect the temperature at the top of the compressor and obtain a compressor temperature value; Controller, the controller is configured to: if the time during which the rotational speed of the compressor is lower than a preset rotational speed exceeds an interval time, then enter an oil return mode; in the oil return mode, control the rotational speed of the compressor to increase to an oil return rotational speed, and continue to operate for an oil return duration and then exit the oil return operation control; At the end of the oil return mode: control the top temperature sensor and the outdoor temperature sensor to respectively obtain the compressor temperature value and the outdoor temperature value; If the difference between the compressor temperature value and the outdoor temperature value is less than a first preset temperature difference, then calculate the oil return rotational speed for the next oil return mode through a first logical calculation; If the difference between the compressor temperature value and the outdoor temperature value is greater than a second preset temperature difference, then calculate the oil return rotational speed for the next oil return mode through a second logical calculation.

[0008] In the technical solution, in the oil return mode, according to the relationship between the difference between the compressor temperature value and the outdoor temperature value and the first preset temperature difference, it is divided into multiple situations, and the oil return rotational speed is adjusted for different situations to achieve stable operation of the oil return mode and avoid frequent start and stop of the compressor, improving the user experience while ensuring the reliability of the compressor.

[0009] In addition, the present application further provides an air conditioner, which includes: Indoor unit; Indoor heat exchanger, the indoor heat exchanger is disposed within the indoor unit; Indoor temperature sensor, the indoor temperature sensor is configured to detect the indoor temperature and obtain an indoor temperature value; Outdoor unit; Outdoor heat exchanger, the outdoor heat exchanger is disposed within the outdoor unit, and the outdoor heat exchanger is in communication with the indoor heat exchanger; Outdoor temperature sensor, the outdoor temperature sensor is configured to detect the outdoor temperature and obtain an outdoor temperature value; Compressor, the compressor is disposed within the outdoor unit, and the compressor is configured to deliver refrigerant to the outdoor heat exchanger and the indoor heat exchanger; An exhaust gas temperature sensor for detecting the exhaust gas temperature of the compressor and obtaining a compressor temperature value; A controller configured to: enter an oil return mode if the time during which the rotational speed of the compressor is lower than a preset rotational speed exceeds an interval time; in the oil return mode, control the rotational speed of the compressor to increase to an oil return rotational speed and continue to operate for an oil return duration before exiting the oil return operation control; At the end of the oil return mode: control the exhaust gas temperature sensor and the outdoor temperature sensor to respectively obtain the compressor temperature value and the outdoor temperature value; If the difference between the compressor temperature value and the outdoor temperature value is less than a first preset temperature difference, calculate the oil return rotational speed for the next oil return mode through a first logic calculation; If the difference between the compressor temperature value and the outdoor temperature value is greater than a second preset temperature difference, calculate the oil return rotational speed for the next oil return mode through a second logic calculation.

[0010] In the technical solution, in the oil return mode, according to the relationship between the difference between the compressor temperature value and the outdoor temperature value and the first preset temperature difference, it is divided into multiple situations, and the oil return rotational speed is adjusted for different situations to achieve stable operation of the oil return mode and avoid frequent start and stop of the compressor, improving the user experience while ensuring the reliability of the compressor.

[0011] In some embodiments of the present application, the controller is configured to: In the cooling mode, the first logic is: F2 = F1 + 0.5×(15 - Td + Tout); In the heating mode, control the indoor temperature sensor to obtain the indoor temperature value; the first logic is: F2 = F1 + 0.5×(15 - Td + Tin); In the cooling mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tout); In the heating mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tin); Wherein, F2 is the oil return rotational speed for the next oil return mode; F1 is the oil return rotational speed in the current oil return mode: Td is the compressor temperature value; Tout is the outdoor temperature value; Tin is the indoor temperature value.

[0012] In the technical solution, through this solution, different scenarios and different operating conditions are distinguished to calculate the oil return rotational speed for the next oil return mode for different situations, so as to ensure that the oil return rotational speed can conform to the current scenario and improve the reliability of the compressor.

[0013] In some embodiments of the present application, the controller is configured to: at the start of the oil return mode, replace the value of the current oil return speed F1 with the value of the next oil return speed F2 calculated in the previous oil return mode.

[0014] In the technical solution, through this setting, it is ensured that the oil return speed in the current oil return mode adopts the oil return speed calculated in the previous oil return mode; and it is ensured that the calculation result of the next oil return speed at the end of the oil return mode is accurate, ensuring the stable operation of the program.

[0015] In some embodiments of the present application, the controller is configured to: if F2 is greater than the oil return upper limit value, control the value of F2 to be the oil return upper limit value; or if F2 is less than the oil return lower limit value, control the value of F2 to be the oil return lower limit value.

[0016] In the technical solution, it is ensured that the oil return speed is within the range between the oil return upper limit value and the oil return lower limit value, avoiding the wear of the compressor and the impact of noise on the user caused by too high or too low oil return speed.

[0017] In some embodiments of the present application, the controller is configured to: if the number of times the oil return mode runs reaches the first preset number of times, and in the first preset number of times, the oil return speed F1 in the current oil return mode is equal to the oil return upper limit value or equal to the oil return lower limit value; In the first adjustment stage: if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration; if the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration.

[0018] In the technical solution, when adjusting the oil return speed multiple times fails to achieve the desired effect, by changing the oil return duration of the oil return mode, the oil return mode is made to conform to the current scenario, improving the reliability of the compressor. Since the extension or shortening of the oil return duration has a greater impact on the user than the oil return speed, in the present application, the oil return speed is adjusted first, and when the oil return speed cannot achieve the effect, the oil return duration is adjusted, minimizing the impact on the user and improving the user experience.

[0019] In some embodiments of the present application, the controller is configured to: if the first adjustment stage runs continuously for the second preset number of times; then start the second adjustment stage; In the second adjustment stage, if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, the interval time until the next oil return mode operation is subtracted by a second time reduction value based on the current interval time; If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, the interval time until the next oil return mode operation is increased by a second time increment value based on the current interval time.

[0020] In the technical solution, when the oil return duration cannot achieve the desired effect after multiple adjustments, the interval time of the oil return mode is changed to make the oil return mode conform to the current scenario and improve the reliability of the compressor. Since the extension or shortening of the interval time of the oil return mode has a greater impact on the user than the oil return duration, in this application, the oil return speed is adjusted first. When the oil return speed cannot achieve the effect, the oil return duration is adjusted. When the oil return duration also cannot achieve the effect, finally, the interval time of the oil return mode, which has the greatest impact on the user, is adjusted, minimizing the impact on the user and improving the user experience.

[0021] In some embodiments of the present application, an indoor fan is provided inside the indoor unit; The controller is configured to: after entering the oil return mode, reduce the speed of the indoor fan so that the temperature value of the indoor heat exchanger is within a preset range.

[0022] In the technical solution, by this solution, the evaporation pressure is reduced in the cooling mode and the condensation pressure is increased in the heating mode to reduce the heat dissipation inside the compressor or increase the heat generation inside the compressor, raise the internal temperature of the compressor, and at the same time reduce the indoor heat exchange amount and the probability of the indoor unit stopping when the set temperature is reached, thereby improving the user experience.

[0023] In some embodiments of the present application, an outdoor fan is provided inside the outdoor unit; The controller is configured to: after entering the oil return mode, reduce the speed of the outdoor fan.

[0024] In the technical solution, the condensation pressure is increased or the evaporation pressure is reduced to reduce the heat dissipation inside the compressor or increase the heat generation inside the compressor, raise the internal temperature of the compressor, and at the same time reduce the indoor heat exchange amount and the probability of the indoor unit stopping when the set temperature is reached, thereby improving the user experience.

[0025] In some embodiments of the present application, the indoor unit has an air outlet of the air conditioner, and a wind deflector is provided at the air outlet of the air conditioner; The controller is configured to: after entering the oil return mode, control the wind deflector to move to a preset position.

[0026] In the technical solution, to avoid the air flow from blowing onto the user, the indoor air volume is reduced to decrease the heat exchange amount, so as to reduce the probability of the air conditioner stopping operation when reaching the set temperature, ensure the comfort of the user, and at the same time, the evaporation temperature will be decreased or the condensation temperature will be increased, the heat dissipation amount of the compressor will be reduced or the heat generation amount of the compressor will be increased, and the internal temperature of the compressor will be raised.

[0027] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present invention. Description of the Drawings

[0028] Figure 1 is a schematic diagram of the overall structure of an air conditioner according to an embodiment of the present application; Figure 2 is a schematic diagram of the structure of an air conditioner according to an embodiment of the present application; Figure 3 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 4 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 5 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 6 is a working flow chart of an air conditioner according to an embodiment of the present application Figure 7 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 8 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 9 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 10 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 11 is a working flow chart of an air conditioner according to an embodiment of the present application; Figure 12 is a working flow chart of an air conditioner according to an embodiment of the present application.

[0029] In the above figures: 100, indoor unit; 200, outdoor unit; 300, indoor heat exchanger; 400, outdoor heat exchanger; 500, compressor. Detailed Embodiments

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In the present invention, unless otherwise clearly defined and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium. It can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. In the present invention, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or merely indicates that the horizontal height of the first feature is less than that of the second feature. In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0031] Next, the present invention will be specifically described by way of exemplary embodiments. However, it should be understood that, without further narration, the elements, structures, and features in one embodiment can also be beneficially combined into other embodiments. In this application, the air conditioner performs the refrigeration cycle of a wall-mounted air conditioner by using a compressor, a condenser, an expansion valve, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, throttling, and evaporation, and supplies cold or heat to the air that has been conditioned and heat-exchanged. The compressor compresses the refrigerant gas in a low-temperature and low-pressure state and discharges the refrigerant gas in a high-temperature and high-pressure state. 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. The expansion valve throttles the high-temperature and high-pressure liquid-phase refrigerant condensed in the condenser into a low-pressure gas-liquid two-phase refrigerant.

[0032] In the evaporator, after the refrigerant expanded in the expansion valve absorbs heat and evaporates, it is in a low-temperature and low-pressure state. Subsequently, the refrigerant gas returns to the compressor. The evaporator can achieve a refrigeration effect by using the latent heat of vaporization of the refrigerant to perform heat exchange with the material to be cooled.

[0033] The air conditioner includes an indoor unit and an outdoor unit, and the indoor unit includes a body. Throughout the cycle, the air conditioner can adjust the temperature of the indoor space. The outdoor unit of the wall-mounted air conditioner refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The indoor unit of the wall-mounted air conditioner includes an indoor heat exchanger, and the expansion valve can be provided in the indoor unit or the outdoor unit. The indoor heat exchanger and the outdoor heat exchanger can be used as a condenser or an evaporator respectively. When the indoor heat exchanger is used as a condenser, the air conditioner serves as a heater in the heating mode. When the indoor heat exchanger is used as an evaporator, the air conditioner serves as a cooler in the cooling mode.

[0034] Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings. As attached Figure 1 and Figure 2 shown, in a schematic embodiment of the air conditioner of the present invention, the air conditioner includes: an indoor unit 100, an indoor heat exchanger 300, an indoor temperature sensor, an outdoor unit 200, an outdoor heat exchanger 400, an outdoor temperature sensor, a compressor 500, a compressor top temperature sensor, and a controller; the indoor heat exchanger 300 is disposed in the indoor unit 100; the indoor temperature sensor is used to detect the indoor temperature and obtain the indoor temperature value; the outdoor heat exchanger 400 is disposed in the outdoor unit 200, and the outdoor heat exchanger 400 is communicated with the indoor heat exchanger 300; the outdoor temperature sensor is used to detect the outdoor temperature and obtain the outdoor temperature value.

[0035] The compressor 500 is disposed in the outdoor unit 200, and the compressor 500 is used to transport the refrigerant to the outdoor heat exchanger 400 and the indoor heat exchanger 300; the compressor top temperature sensor is used to detect the temperature at the top of the compressor 500 and obtain the compressor temperature value.

[0036] Please refer to Figures 3 to 12, the controller is configured to: enter the oil return mode if the time when the rotational speed of the compressor 500 is lower than the preset rotational speed exceeds the interval time; in the oil return mode, control the rotational speed of the compressor 500 to increase to the oil return rotational speed, and continue to operate until after the oil return duration, then exit the oil return operation control; at the end of the oil return mode: control the top pressure temperature sensor and the outdoor temperature sensor to obtain the compressor temperature value and the outdoor temperature value respectively; if the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, calculate the oil return rotational speed of the next oil return mode through the first logic calculation; if the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, calculate the oil return rotational speed of the next oil return mode through the second logic calculation.

[0037] Through the above solution, in the oil return mode, according to the relationship between the difference between the compressor temperature value and the outdoor temperature value and the first preset temperature difference, there are multiple situations, and the oil return rotational speed is adjusted for different situations to achieve stable operation of the oil return mode and avoid frequent start and stop of the compressor 500, improving the user experience while ensuring the reliability of the compressor 500.

[0038] In the prior art, a top pressure temperature sensor has been provided inside the outdoor unit 200 of some air conditioners, which is used to detect the temperature at the top of the compressor 500. In this application, when facing this type of model, the top pressure temperature sensor of it can be directly used without the need to separately set a temperature sensor, saving costs.

[0039] Please refer to Figure 1 and Figure 2 , in addition, this application also provides an air conditioner, which includes: an indoor unit 100, an indoor heat exchanger 300, an indoor temperature sensor, an outdoor unit 200, an outdoor heat exchanger 400, an outdoor temperature sensor, a compressor 500, an exhaust temperature sensor, and a controller; wherein, the indoor heat exchanger 300 is arranged inside the indoor unit 100; the indoor temperature sensor is used to detect the indoor temperature and obtain the indoor temperature value; the outdoor heat exchanger 400 is arranged inside the outdoor unit 200, and the outdoor heat exchanger 400 is communicated with the indoor heat exchanger 300; the outdoor temperature sensor is used to detect the outdoor temperature and obtain the outdoor temperature value.

[0040] The compressor 500 is arranged inside the outdoor unit 200, and the compressor 500 is used to convey the refrigerant to the outdoor heat exchanger 400 and the indoor heat exchanger 300; the exhaust temperature sensor is used to detect the exhaust temperature of the compressor 500 and obtain the compressor temperature value.

[0041] Please refer to Figures 3 to 12, the controller is configured to: enter the oil return mode if the rotation speed of the compressor 500 is lower than the preset rotation speed for a time exceeding the interval time; in the oil return mode, control the rotation speed of the compressor 500 to increase to the oil return rotation speed, and continue to operate until the oil return duration is reached and then exit the oil return operation control; at the end of the oil return mode: control the exhaust temperature sensor and the outdoor temperature sensor to obtain the compressor temperature value and the outdoor temperature value respectively; if the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, calculate the oil return rotation speed of the next oil return mode through the first logic calculation; if the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, calculate the oil return rotation speed of the next oil return mode through the second logic calculation.

[0042] Through the above solution, in the oil return mode, according to the relationship between the difference between the compressor temperature value and the outdoor temperature value and the first preset temperature difference, there are multiple situations, and the oil return rotation speed is adjusted for different situations to achieve stable operation of the oil return mode and avoid frequent start and stop of the compressor 500, improving the user experience while ensuring the reliability of the compressor 500.

[0043] In the prior art, an exhaust temperature sensor has been set inside the outdoor unit 200 of some air conditioners, which is used to detect the temperature at the top of the compressor 500. In this application, when facing this type of model, the exhaust temperature sensor can be directly used, and there is no need to separately set a temperature sensor, saving costs.

[0044] In some embodiments, the indoor unit 100 is installed indoors, the outdoor unit 200 is installed outdoors, the indoor heat exchanger 300 is connected and communicated with the outdoor heat exchanger 400, and the refrigerant flows between the indoor heat exchanger 300 and the outdoor heat exchanger 400 through the compressor 500 to realize the change of the temperature of the indoor heat exchanger 300. The air flow passing through the indoor heat exchanger 300 is heated and then flows indoors to realize the change of the indoor temperature.

[0045] In some embodiments, when the air conditioner runs the oil return mode for the first time, the oil return rotation speed, the oil return duration, and the interval time in the oil return mode are all preset values, and the specific values can be preset at the factory, sent from the cloud, preset by the user, and other forms.

[0046] Please refer to Figures 3 to 12 , in some embodiments, the controller is configured to: judge whether the rotation speed of the compressor 500 is lower than the preset rotation speed. If not, operate in the current state; if so, record the running time and judge whether the running time exceeds the interval time; if not, continue to record the running time; if so, enter the oil return mode.

[0047] In some embodiments, after entering the oil return mode, if the compressor temperature value minus the outdoor temperature value is less than the first preset temperature difference, the oil return speed for the next oil return mode is calculated through the first logic.

[0048] In some embodiments, the first preset temperature difference is 15°C.

[0049] In some embodiments, after entering the oil return mode, if the compressor temperature value minus the outdoor temperature value is greater than the second preset temperature difference, the oil return speed for the next oil return mode is calculated through the second logic.

[0050] In some embodiments, the second preset temperature difference is 25°C.

[0051] In some embodiments, the controller is configured such that in the cooling mode, the first logic is: F2 = F1 + 0.5×(15 - Td + Tout).

[0052] In the heating mode, the indoor temperature sensor is controlled to obtain the indoor temperature value; the first logic is: F2 = F1 + 0.5×(15 - Td + Tin).

[0053] In the cooling mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tout).

[0054] In the heating mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tin). In the above formulas, F2 is the oil return speed for the next oil return mode; F1 is the oil return speed in the current oil return mode: Td is the compressor temperature value; Tout is the outdoor temperature value; Tin is the indoor temperature value. Through this solution, different scenarios and operating conditions are distinguished to calculate the oil return speed for the next oil return mode for different situations, so as to ensure that the oil return speed can conform to the current scenario and improve the reliability of the compressor 500.

[0055] Hereinafter, the oil return speed F1 in the current oil return mode is simply referred to as the current oil return speed F1; the oil return speed F2 for the next oil return mode is simply referred to as the next oil return speed F2.

[0056] Please refer to Figures 3 to 12 , in some embodiments, at the end of the oil return mode, the compressor top temperature sensor and the outdoor temperature sensor are controlled to obtain the compressor temperature value and the outdoor temperature value respectively. It is judged whether the compressor temperature value minus the outdoor temperature value is less than the first preset temperature difference; if so, the first logic is entered; if not, it is judged whether the compressor temperature value minus the outdoor temperature value is greater than the second preset temperature difference; if so, the second logic is entered; if not, the oil return mode is exited, and the current oil return duration, oil return speed, and interval time are applied to the next oil return mode.

[0057] In some embodiments, it is determined in the first logic whether the current mode is the heating mode. If so, the oil return speed F2 for the next oil return mode is calculated by F2 = F1 + 0.5×(15 - Td + Tin). If not, the oil return speed F2 for the next oil return mode is calculated by F2 = F1 + 0.5×(15 - Td + Tout).

[0058] Under the condition that the oil return mode is turned on, the air conditioner will only be in the heating mode, the cooling mode, and the dehumidification mode. In both the cooling mode and the dehumidification mode, the oil return speed F2 for the next oil return mode is calculated by F2 = F1 + 0.5×(15 - Td + Tout). Therefore, it is only necessary to determine whether the current mode is the heating mode.

[0059] It should be noted that the end of the oil return mode means that the speed of the compressor 500 is increased to the oil return speed and continues to run for the oil return duration. In addition, it is also possible to first determine whether the current mode is the heating mode or the cooling mode, and then determine whether the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference.

[0060] In some embodiments, the complete sequence of entering the second logic in the oil return mode is as follows: determine whether the current mode is the heating mode. If so, the oil return speed F2 for the next oil return mode is calculated by F2 = F1 - 0.5×(25 - Td + Tin). If not, determine whether the current mode is the cooling mode. If so, the oil return speed F2 for the next oil return mode is calculated by F2 = F1 - 0.5×(25 - Td + Tout).

[0061] It should be noted that the order of determining the heating mode or the cooling mode can be changed. In addition, it is also possible to first determine whether the current mode is the heating mode or the cooling mode, and then determine whether the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference.

[0062] In some embodiments, both the first logic and the second logic are programs within the oil return mode, which are executed when the current oil return mode ends. After obtaining the result of F2 through the first logic or the second logic, the oil return mode is exited.

[0063] In some embodiments, the first logic and the second logic are separate adjustment modes, and the adjustment mode runs immediately after the oil return mode ends.

[0064] The controller is configured to: at the start of the oil return mode, replace the value of the current oil return speed F1 with the value of the next oil return speed F2 calculated in the previous oil return mode. For example, if the oil return speed F2 calculated in the previous oil return mode is 30 rps, then the oil return speed F1 in the current oil return mode is 30 rps. Through this setting, it is ensured that the oil return speed in the current oil return mode adopts the oil return speed calculated in the previous oil return mode; and it is ensured that the calculation result of the next oil return speed at the end of the oil return mode is accurate, ensuring the stable operation of the program.

[0065] In some embodiments, the controller is configured to: if F2 is greater than the oil return upper limit value, control the value of F2 to be the oil return upper limit value; or if F2 is less than the oil return lower limit value, control the value of F2 to be the oil return lower limit value. Ensure that the oil return speed is within the range between the oil return upper limit value and the oil return lower limit value, avoiding the wear of the compressor 500 caused by too high or too low oil return speed and the impact of noise on the user.

[0066] In some embodiments, the oil return upper limit value is 40 rps and the oil return lower limit value is 30 rps. When the value of F2 is greater than 40, the oil return speed F2 for the next oil return mode is defaulted to 40 rps. If the value of F2 is less than 30, the oil return speed F2 for the next oil return mode is defaulted to 30 rps.

[0067] Please refer to Figures 3 to 12 , in some embodiments, the controller is configured to: if the number of times the oil return mode runs reaches the first preset number of times, and in the first preset number of times the oil return speed F1 in the current oil return mode is equal to the oil return upper limit value or equal to the oil return lower limit value, then start the first adjustment stage.

[0068] Further, the controller is configured to: judge whether the number of times the current oil return speed F1 is equal to the oil return upper limit value in the first preset number of times reaches the first preset number of times during several consecutive oil return mode operations. If so, enter the first adjustment stage. If not, judge whether the number of times the current oil return speed F1 is equal to the oil return lower limit value in the first preset number of times reaches the first preset number of times. If so, enter the first adjustment stage; if not, operate normally in the current state and enter the oil return mode.

[0069] In another embodiment, the controller is configured to: judge whether the number of times the current oil return speed F1 is equal to the oil return lower limit value in the first preset number of times reaches the first preset number of times during several consecutive oil return mode operations. If so, enter the first adjustment stage; if not, judge whether the number of times the current oil return speed F1 is equal to the oil return upper limit value in the first preset number of times reaches the first preset number of times. If so, enter the first adjustment stage. If not, operate normally in the current state and enter the oil return mode.

[0070] Please refer to Figures 3 to 12, in some embodiments, the controller is configured to determine whether the current oil return speed F1 is equal to the upper limit value or the lower limit value of oil return. If not, the oil return mode continues to operate in the current state; if so, it is determined whether the number of times the current oil return speed F1 is equal to the upper limit value or the lower limit value of oil return reaches a first preset number of times. If so, the first adjustment mode is entered; if not, the oil return mode continues to operate in the current state.

[0071] In some embodiments, the controller is configured to record the number of times if the current oil return speed F1 is equal to the upper limit value or the lower limit value of oil return. If the number of times reaches the first preset number of times, the first adjustment stage is entered. If the current oil return speed F1 is not equal to the upper limit value or the lower limit value of oil return, the recorded number of times is cleared.

[0072] Specifically, the controller is configured to determine whether the current oil return speed F1 is equal to the upper limit value or the lower limit value of oil return. If not, the recorded number of times is cleared, and the oil return mode continues to operate in the current state; if so, the value of the recorded number of times is incremented by one, and it is determined whether the current recorded number of times reaches the first preset number of times. If so, the first adjustment stage is entered; if not, the oil return mode continues to operate in the current state.

[0073] In another embodiment, the controller is configured to: if the number of times the oil return mode runs reaches the first preset number of times, and the next oil return speed F2 is equal to the upper limit value or the lower limit value of oil return during the first preset number of times, the first adjustment stage is started. It should be noted that the content for determining whether to enter the first adjustment stage by the next oil return speed F2 is the same as the content for determining whether to enter the first adjustment stage by the current oil return speed F1 above.

[0074] In some embodiments, the first preset number of times is any value from 3 to 5.

[0075] In some embodiments, the controller is configured to: before the first adjustment stage, calculate the temperature obtained by subtracting the outdoor temperature value from the compressor temperature value to obtain a temperature difference. If the temperature difference is greater than the first preset temperature difference and less than the second preset temperature difference, the first adjustment stage is not entered. If the temperature difference is less than the first preset temperature difference or greater than the second preset temperature difference, the first adjustment stage is entered.

[0076] Specifically, the controller is configured to: if the number of times the oil return mode runs reaches the first preset number of times, and the oil return speed F1 in the current oil return mode is equal to the upper limit value or the lower limit value of oil return during the first preset number of times, calculate the temperature obtained by subtracting the outdoor temperature value from the compressor temperature value to obtain a temperature difference, and determine whether the temperature difference is less than the first preset temperature difference. If so, the first adjustment stage is entered; if not, determine whether the temperature difference is greater than the second preset temperature difference. If so, the first adjustment stage is entered; if not, the first adjustment stage is not entered, and the current oil return mode continues.

[0077] Please refer to Figures 3 to 12 , in some embodiments, in the first adjustment stage: if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration; if the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration. When adjusting the oil return speed multiple times fails to achieve the desired effect, the oil return duration of the oil return mode is changed to make the oil return mode conform to the current scenario, thereby improving the reliability of the compressor 500. Since the extension or shortening of the oil return duration has a greater impact on the user than the oil return speed, in this application, the oil return speed is adjusted first. When the oil return speed cannot achieve the effect, the oil return duration is adjusted, minimizing the impact on the user and improving the user experience.

[0078] Further, in the first adjustment stage: if the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration. If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration.

[0079] Furthermore, in the first adjustment stage: it is judged whether the temperature difference is less than the first preset temperature difference. If so, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration; if not, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration. Since it has been confirmed that there are only two cases for the temperature difference, i.e., less than the first preset temperature difference or greater than the second preset temperature difference, when entering the first adjustment stage, if it is judged that the temperature difference is less than the first preset temperature difference, it can be directly determined that the temperature difference is greater than the second preset temperature difference.

[0080] In another embodiment, in the first adjustment stage: it is judged whether the temperature difference is greater than the second preset temperature difference. If not, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration; if so, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration.

[0081] In some embodiments, both the first time increment and the first time decrement are half a minute, i.e., 0.5 min.

[0082] In some embodiments, the oil return duration has an upper limit value and a lower limit value, which are the duration upper limit value and the duration lower limit value respectively. If the finally calculated oil return duration is lower than the duration lower limit value, the oil return duration is replaced with the duration lower limit value; if the finally calculated oil return duration is higher than the duration upper limit value, the oil return duration is replaced with the duration upper limit value.

[0083] Furthermore, the range of the oil return duration is between 1 and 3 minutes, that is, the upper limit of the duration is 3 minutes and the lower limit of the duration is 1 minute. If the finally calculated oil return duration is lower than 1 minute, the oil return duration of the next oil return mode is 1 minute; if the finally calculated oil return duration is higher than 3 minutes, the oil return duration of the next oil return mode is 3 minutes.

[0084] In some embodiments, the controller is configured to: if the first adjustment stage runs continuously for a second preset number of times, start the second adjustment stage. Furthermore, the controller is configured to: if it is determined that the first adjustment stage has been entered in each of the second preset number of consecutive oil return modes, enter the second adjustment stage.

[0085] In some embodiments, the controller is configured to: before the second adjustment stage, calculate the temperature obtained by subtracting the outdoor temperature value from the compressor temperature value to obtain a temperature difference. If the temperature difference is greater than the first preset temperature difference and less than the second preset temperature difference, do not enter the second adjustment stage. If the temperature difference is less than the first preset temperature difference or greater than the second preset temperature difference, enter the second adjustment stage.

[0086] Specifically, the controller is configured to: if the number of runs of the first adjustment stage reaches the second preset number, calculate the temperature obtained by subtracting the outdoor temperature value from the compressor temperature value to obtain a temperature difference, and determine whether the temperature difference is less than the first preset temperature difference. If so, enter the second adjustment stage; if not, determine whether the temperature difference is greater than the second preset temperature difference. If so, enter the second adjustment stage; if not, do not enter the second adjustment stage and continue the current oil return mode.

[0087] Please refer to Figures 3 to 12, in some embodiments, during the second adjustment stage; if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, the interval time until the next oil return mode operation is reduced by a second time reduction value based on the current interval time; if the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, the interval time until the next oil return mode operation is increased by a second time increase value based on the current interval time. When the oil return duration cannot achieve the desired effect after multiple adjustments, the interval time of the oil return mode is changed to make the oil return mode conform to the current scenario, thereby improving the reliability of the compressor 500. Since the extension or shortening of the interval time of the oil return mode has a greater impact on the user than the oil return duration, in this application, the oil return speed is first adjusted. When the oil return speed cannot achieve the effect, the oil return duration is then adjusted. When the oil return duration also cannot achieve the effect, finally, the interval time of the oil return mode, which has the greatest impact on the user, is adjusted, minimizing the impact on the user and improving the user experience.

[0088] In some embodiments, the controller is configured to: if entering the first adjustment stage, record the number of times. If the number of times reaches the second preset number of times, enter the second adjustment stage. If not entering the first adjustment stage, clear the recorded number of times.

[0089] Specifically, the controller is configured to determine whether it has entered the first adjustment stage. If not, clear the recorded number of times and continue to operate the oil return mode in the current state; if so, increment the value of the recorded number of times by one, and determine whether the current recorded number of times reaches the second preset number of times. If so, enter the second adjustment stage; if not, continue to operate the oil return mode in the current state.

[0090] Furthermore, during the second adjustment stage: determine whether the temperature difference is less than the first preset temperature difference. If so, the interval time in the next oil return mode is increased by a second time increase value based on the current interval time; if not, the interval time in the next oil return mode is reduced by a second time reduction value based on the current interval time. Since it has been confirmed that there are only two cases for the temperature difference, i.e., less than the first preset temperature difference or greater than the second preset temperature difference, when entering the first adjustment stage, if it is determined that the temperature difference is greater than the first preset temperature difference, it can be directly determined that the temperature difference is greater than the second preset temperature difference.

[0091] In another embodiment, during the second adjustment stage: determine whether the temperature difference is greater than the second preset temperature difference. If not, the interval time in the next oil return mode is increased by a second time increase value based on the current interval time; if so, the interval time in the next oil return mode is reduced by a second time reduction value based on the current interval time.

[0092] In some embodiments, both the second time increment and the second time decrement are 5 minutes, i.e., 5 min.

[0093] In some embodiments, the interval time has an upper limit value and a lower limit value, which are the interval time upper limit value and the interval time upper limit value respectively. If the finally calculated interval time is lower than the interval time lower limit value, the interval time is replaced with the interval time lower limit value; if the finally calculated interval time is higher than the interval time upper limit value, the interval time is replaced with the duration upper limit value.

[0094] Further, the range of the interval time is 0.5 to 1 hour, i.e., the upper limit of the interval time is 1 hour and the lower limit value of the interval time is 30 minutes. If the finally calculated interval time is lower than 30 minutes, the interval time until the next oil return mode is 30 minutes; if the finally calculated interval time is higher than 1 hour, the interval time until the next oil return mode is 1 hour.

[0095] In some embodiments, in the second adjustment stage: when the compressor temperature value minus the outdoor temperature value is less than the first preset temperature difference, the interval time until the next oil return mode is increased by the second time increment on the basis of the current interval time. When the compressor temperature value minus the outdoor temperature value is greater than the second preset temperature difference, the interval time until the next oil return mode is decreased by the second time decrement on the basis of the current interval time.

[0096] In some embodiments, an indoor fan is provided inside the indoor unit 100; the controller is configured to: after entering the oil return mode, reduce the rotational speed of the indoor fan so that the temperature value of the indoor heat exchanger 300 is within a preset range. Through this solution, the evaporation pressure is reduced in the cooling mode and the condensation pressure is increased in the heating mode, so as to reduce the heat dissipation inside the compressor 500 or increase the heat generation inside the compressor 500, raise the temperature inside the compressor 500, and at the same time, the indoor heat exchange amount can be reduced, and the probability of the indoor unit stopping when reaching the set temperature can be reduced, thereby improving the user experience.

[0097] In some embodiments, an outdoor fan is provided inside the outdoor unit 200; the controller is configured to: after entering the oil return mode, reduce the rotational speed of the outdoor fan. Increase the condensation pressure or reduce the evaporation pressure, so as to reduce the heat dissipation inside the compressor 500 or increase the heat generation inside the compressor 500, raise the temperature inside the compressor 500, and at the same time, the indoor heat exchange amount can be reduced, and the probability of the indoor unit stopping when reaching the set temperature can be reduced, thereby improving the user experience.

[0098] In some embodiments, the indoor unit 100 has an air outlet of the air conditioner, and a wind deflector is provided at the air outlet of the air conditioner; the controller is configured to: after entering the oil return mode, control the wind deflector to move to a preset position. To avoid the air flow blowing on the user, reduce the indoor air volume to reduce the heat exchange amount, so as to reduce the probability of the air conditioner stopping when reaching the set temperature, ensure the comfort of the user, and at the same time, the evaporation temperature will be reduced or the condensation temperature will be increased, the heat dissipation amount of the compressor 500 will be reduced or the heat generation amount of the compressor 500 will be increased, and the internal temperature of the compressor 500 will be increased.

[0099] In some embodiments, if the first adjustment stage and / or the second adjustment stage are not entered, the oil return mode is exited.

[0100] In some embodiments, at the start of the oil return mode, the value of the current oil return speed F1 is replaced with the value of the next oil return speed F2 calculated in the previous oil return mode. And the oil return duration calculated in the previous oil return mode is applied. Or, at the end of the oil return mode, the calculated next oil return speed is applied to the next oil return mode, and the oil return duration calculated this time is applied to the next oil return mode.

[0101] Further, if the first adjustment stage is not entered, the oil return speed is applied in the next oil return mode. If the first adjustment stage is entered, only the oil return duration is applied in the next oil return mode. If the second adjustment stage is entered, only the interval time is applied.

[0102] In some embodiments, a four-way valve is provided between the indoor heat exchanger 300 and the outdoor heat exchanger 400, and the flow direction of the refrigerant is adjusted through the four-way valve to change the cooling mode or heating mode of the air conditioner.

[0103] Please refer to Figures 3 to 12 , in the present application, the controller is configured to: determine whether the speed of the compressor 500 is lower than a preset speed. If not, it operates in the current state. If so, record the running time thereof, and determine whether the running time exceeds the interval time. If not, continue to record the running time thereof. If so, enter the oil return mode.

[0104] In the oil return mode, control the speed of the compressor 500 to be increased to the oil return speed and continuously operate for the oil return duration.

[0105] Control the top pressure temperature sensor and the outdoor temperature sensor to obtain the compressor temperature value and the outdoor temperature value respectively. Determine whether the compressor temperature value minus the outdoor temperature value is less than a first preset temperature difference. If so, enter the first logic. If not, determine whether the compressor temperature value minus the outdoor temperature value is greater than a second preset temperature difference. If so, enter the second logic. If not, exit the oil return mode, and apply the current oil return duration, oil return speed and interval time to the next oil return mode.

[0106] In the first logic, it is determined whether the current mode is the heating mode or the cooling mode. If it is the heating mode, the next oil return speed F2 is calculated by F2 = F1 + 0.5×(15 - Td + Tin). If it is the cooling mode, the next oil return speed F2 is calculated by F2 = F1 + 0.5×(15 - Td + Tout).

[0107] In the second logic, it is determined whether the current mode is the heating mode or the cooling mode. If it is the heating mode, the next oil return speed F2 is calculated by F2 = F1 - 0.5×(25 - Td + Tin). If it is the cooling mode, the next oil return speed F2 is calculated by F2 = F1 - 0.5×(25 - Td + Tout).

[0108] If F2 is greater than the upper limit value of oil return, the value of F2 is controlled to be the upper limit value of oil return; or if F2 is less than the lower limit value of oil return, the value of F2 is controlled to be the lower limit value of oil return.

[0109] If the number of times the oil return mode runs reaches the first preset number of times, and in the first preset number of times, the oil return speed F1 in the current oil return mode is equal to the upper limit value of oil return or equal to the lower limit value of oil return, and the temperature obtained by calculating the compressor temperature value minus the outdoor temperature value is used to obtain the temperature difference. If the temperature difference is less than the first preset temperature difference or greater than the second preset temperature difference, the first adjustment stage is entered.

[0110] In the first adjustment stage, if the temperature difference is less than the first preset temperature difference, the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration. If the temperature difference is greater than the second preset temperature difference, the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration.

[0111] If it is calculated that the next oil return duration is lower than the lower limit value of the duration, the next oil return duration is replaced with the lower limit value of the duration; if it is calculated that the next oil return duration is higher than the upper limit value of the duration, the next oil return duration is replaced with the upper limit value of the duration.

[0112] If the first adjustment stage is continuously run to reach the second preset number of times; and the temperature difference is less than the first preset temperature difference or greater than the second preset temperature difference, the second adjustment stage is entered.

[0113] In the second adjustment stage, if the temperature difference is less than the first preset temperature difference, the interval time until the next oil return mode operation is decreased by the second time decrement on the basis of the current interval time. If the temperature difference is greater than the second preset temperature difference, the interval time until the next oil return mode operation is increased by the second time increment on the basis of the current interval time.

[0114] If the calculated interval time is lower than the lower limit value of the interval time, the interval time shall be replaced with the lower limit value of the interval time; if the calculated interval time is higher than the upper limit value of the interval time, the interval time shall be replaced with the upper limit value of the duration.

[0115] After the end of the oil return mode, the calculated interval time is applied.

[0116] At the start of the oil return mode, the value of the current oil return speed F1 is replaced with the value of the next oil return speed F2 calculated in the previous oil return mode. And the oil return duration calculated in the previous oil return mode is applied.

[0117] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. An air conditioner, characterized in that, It includes: An indoor unit; An indoor heat exchanger, which is arranged inside the indoor unit; An indoor temperature sensor, which is used to detect the indoor temperature and obtain the indoor temperature value; An outdoor unit; An outdoor heat exchanger, which is arranged inside the outdoor unit and is connected to the indoor heat exchanger; An outdoor temperature sensor, which is used to detect the outdoor temperature and obtain the outdoor temperature value; A compressor, which is arranged inside the outdoor unit and is used to deliver refrigerant to the outdoor heat exchanger and the indoor heat exchanger; A top temperature sensor, which is used to detect the temperature at the top of the compressor and obtain the compressor temperature value; A controller, which is configured to: if the time when the rotational speed of the compressor is lower than the preset rotational speed exceeds the interval time, enter the oil return mode; in the oil return mode, control the rotational speed of the compressor to increase to the oil return rotational speed and continue to operate for the oil return duration and then exit the oil return operation control; At the end of the oil return mode: control the top temperature sensor and the outdoor temperature sensor to obtain the compressor temperature value and the outdoor temperature value respectively; If the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, calculate the oil return rotational speed for the next oil return mode through the first logic calculation; If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, calculate the oil return rotational speed for the next oil return mode through the second logic calculation.

2. An air conditioner, characterized in that, It includes: An indoor unit; An indoor heat exchanger, which is arranged inside the indoor unit; An indoor temperature sensor, which is used to detect the indoor temperature and obtain the indoor temperature value; An outdoor unit; An outdoor heat exchanger, which is arranged inside the outdoor unit and is connected to the indoor heat exchanger; An outdoor temperature sensor, which is used to detect the outdoor temperature and obtain the outdoor temperature value; A compressor, which is arranged inside the outdoor unit and is used to deliver refrigerant to the outdoor heat exchanger and the indoor heat exchanger; An exhaust temperature sensor, which is used to detect the exhaust temperature of the compressor and obtain the compressor temperature value; A controller, which is configured to: if the time when the rotational speed of the compressor is lower than the preset rotational speed exceeds the interval time, enter the oil return mode; in the oil return mode, control the rotational speed of the compressor to increase to the oil return rotational speed and continue to operate for the oil return duration and then exit the oil return operation control; At the end of the oil return mode: control the exhaust temperature sensor and the outdoor temperature sensor to obtain the compressor temperature value and the outdoor temperature value respectively; If the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, calculate the oil return rotational speed for the next oil return mode through the first logic calculation; If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, calculate the oil return rotational speed for the next oil return mode through the second logic calculation.

3. The air conditioner according to claim 1 or 2, characterized in that The controller is configured to: In the refrigeration mode, the first logic is: F2 = F1 + 0.5×(15 - Td + Tout); In the heating mode, the controller is configured to control the indoor temperature sensor to obtain the indoor temperature value; the first logic is: F2 = F1 + 0.5×(15 - Td + Tin); In the refrigeration mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tout); In the heating mode, the second logic is: F2 = F1 - 0.5×(25 - Td + Tin); Wherein, F2 is the oil return speed of the next oil return mode; F1 is the oil return speed in the current oil return mode: Td is the compressor temperature value; Tout is the outdoor temperature value; Tin is the indoor temperature value.

4. The air conditioner according to claim 3, characterized in that, The controller is configured to: at the start of the oil return mode, replace the value of the current oil return speed F1 with the value of the next oil return speed F2 calculated in the previous oil return mode.

5. The air conditioner according to claim 3, characterized in that, The controller is configured to: if the F2 is greater than the oil return upper limit value, control the value of the F2 to be the oil return upper limit value; Or if F2 is less than the oil return lower limit value, control the value of the F2 to be the oil return lower limit value.

6. The air conditioner according to claim 5, characterized in that, The controller is configured to: if the number of times the oil return mode runs reaches the first preset number of times, and in the first preset number of times, the oil return speed F1 in the current oil return mode is equal to the oil return upper limit value or equal to the oil return lower limit value, then start the first adjustment stage; In the first adjustment stage: if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, then the oil return duration in the next oil return mode is increased by the first time increment on the basis of the current oil return duration; If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, then the oil return duration in the next oil return mode is decreased by the first time decrement on the basis of the current oil return duration.

7. The air conditioner according to claim 6, characterized in that The controller is configured to: if the first adjustment stage runs continuously for the second preset number of times; then start the second adjustment stage; In the second adjustment stage; if it is determined that the difference between the compressor temperature value and the outdoor temperature value is less than the first preset temperature difference, then the interval time until the next oil return mode operation is decreased by the second time decrement on the basis of the current interval time; If the difference between the compressor temperature value and the outdoor temperature value is greater than the second preset temperature difference, then the interval time until the next oil return mode operation is increased by the second time increment on the basis of the current interval time.

8. The air conditioner according to claim 1 or 2, characterized in that, An indoor fan is provided inside the indoor unit; The controller is configured to: after entering the oil return mode, reduce the speed of the indoor fan so that the temperature value of the indoor heat exchanger is within a preset range.

9. The air conditioner according to claim 1 or 2, characterized in that, An outdoor fan is provided inside the outdoor unit; The controller is configured to: after entering the oil return mode, reduce the speed of the outdoor fan.

10. The air conditioner according to claim 1 or 2, characterized in that, The indoor unit has an air outlet of the air conditioner, and a wind deflector is provided at the air outlet of the air conditioner; The controller is configured to: after entering the oil return mode, control the wind deflector to move to a preset position.

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