Compressor oil return control system, method, and medium

Abstract

This application discloses a compressor oil return control system, method, and medium. The system includes: a compressor; an oil separator, the inlet of which is connected to the compressor's discharge port, and the first outlet of the oil separator connected to the compressor's suction port via an oil return pipe; a multi-way valve, the first end of which is connected to the second outlet of the oil separator; an indoor heat exchanger, one end of which is connected to the second end of the multi-way valve; an outdoor heat exchanger, one end of which is connected to the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger connected to the third end of the multi-way valve; and a gas-liquid separator, the inlet of which is connected to the compressor's discharge port via a first electronic expansion valve, the first outlet of which is connected to the compressor's suction port via a first solenoid valve, the second outlet of which is connected to the compressor's suction port via a second electronic expansion valve, and the inlet of which is also connected to the fourth end of the multi-way valve via a second solenoid valve. This system can prevent the compressor from experiencing oil shortage.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of air conditioning technology, and in particular to a compressor oil return control system, method, and medium. Background Technology

[0002] To lubricate the compressor during operation, a certain amount of refrigerant oil is usually added to the refrigerant. However, during air conditioning operation, some refrigerant oil inevitably escapes from the compressor. When heating at low temperatures, the refrigerant oil tends to deposit at the bottom of the gas-liquid separator along with the liquid refrigerant, taking a relatively long time to return to the compressor. During this process, the compressor may experience oil shortage. Summary of the Invention

[0003] This application provides a compressor oil return control system, method, and medium that can prevent compressor oil shortage caused by long-term deposition of refrigeration oil at the bottom of the gas-liquid separator.

[0004] In a first aspect, embodiments of this application provide a compressor oil return control system, the control system comprising: compressor; An oil separator, wherein the inlet of the oil separator is connected to the exhaust port of the compressor, and the first outlet of the oil separator is connected to the suction port of the compressor through an oil return pipe; A multi-way valve, wherein the first end of the multi-way valve is connected to the second outlet of the oil separator; An indoor heat exchanger, one end of which is connected to the second end of the multi-way valve; An outdoor heat exchanger, one end of which is connected to the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger is connected to the third end of the multi-way valve. The gas-liquid separator has an inlet connected to the exhaust port of the compressor via a first electronic expansion valve, a first outlet connected to the suction port of the compressor via a first solenoid valve, a second outlet connected to the suction port of the compressor via a second electronic expansion valve, and an inlet also connected to the fourth end of the multi-way valve via a second solenoid valve. The first outlet of the gas-liquid separator is located at the bottom of the gas-liquid separator.

[0005] In some embodiments, the return oil pipe is provided with a return oil temperature detection element.

[0006] In some embodiments, the second outlet of the oil separator is provided with an exhaust temperature detection element and a high-pressure sensor, the suction port of the compressor is provided with a suction temperature detection element, the inlet of the gas-liquid separator is provided with a low-pressure sensor, and the bottom of the gas-liquid separator is provided with a bottom temperature detection element.

[0007] In some embodiments, the indoor heat exchanger is provided with an indoor temperature detection element, the outdoor heat exchanger is provided with an outdoor temperature detection element, and a third electronic expansion valve is provided between the indoor heat exchanger and the outdoor heat exchanger.

[0008] Secondly, embodiments of this application provide a compressor oil return control method, applied to a controller of a compressor oil return control system as described in the first aspect embodiment. The controller is electrically connected to the compressor, the oil separator, the multi-way valve, the gas-liquid separator, the first electronic expansion valve, the first solenoid valve, the second electronic expansion valve, the second solenoid valve, the indoor heat exchanger, and the outdoor heat exchanger, respectively. The control method includes: In heating mode, the first electronic expansion valve and the first solenoid valve are closed, and the second electronic expansion valve and the second solenoid valve are opened, so that the refrigerant output by the compressor passes sequentially through the oil separator, the first and second ends of the multi-way valve, the indoor heat exchanger, the outdoor heat exchanger, the third and fourth ends of the multi-way valve, and the gas-liquid separator before returning to the compressor. The bottom temperature of the gas-liquid separator and the first gas pressure at the inlet of the gas-liquid separator are obtained; Determine the evaporation temperature of the refrigerant based on the first atmospheric pressure; When the difference between the bottom temperature and the evaporation temperature is less than the first preset temperature and remains so for the first preset time, the system enters the rapid oil return mode. In the rapid oil return mode, the first electronic expansion valve and the first solenoid valve are opened, and the second electronic expansion valve and the second solenoid valve are closed. High-pressure gas is supplied to the top of the gas-liquid separator through the compressor, and the refrigerant oil deposited at the bottom of the gas-liquid separator is returned to the compressor through the pressure difference.

[0009] In some embodiments, after entering the rapid oil return mode, the control method further includes: The discharge temperature of the compressor and the second air pressure at the discharge port of the compressor are obtained; The condensation temperature of the refrigerant is determined based on the second gas pressure. The opening degree of the first electronic expansion valve in rapid oil return mode is determined based on the exhaust temperature and the condensation temperature; the opening degree is determined by the following formula: ; in, This indicates the opening degree of the first electronic expansion valve in the current cycle. This indicates the opening degree of the first electronic expansion valve in the previous cycle. And C is a constant. This indicates the exhaust temperature. This indicates the condensation temperature.

[0010] In some embodiments, after entering the rapid oil return mode, the control method further includes: Obtain the suction temperature of the compressor; When the intake temperature is greater than the second preset temperature, the second electronic expansion valve and the second solenoid valve are opened until the intake temperature is less than the third preset temperature, at which point the second electronic expansion valve and the second solenoid valve are closed; wherein the third preset temperature is less than the second preset temperature.

[0011] In some embodiments, after entering the rapid oil return mode, the control method further includes: Get the first difference between the set temperature and the indoor temperature in the current cycle and the second difference in the previous cycle; When the difference between the first difference and the second difference is greater than a preset value, the operating frequency of the compressor is increased until the difference between the first difference and the second difference is less than or equal to 0 or the rapid oil return mode is exited; wherein, the operating frequency of the compressor is determined by the following formula: ; in, This indicates the operating frequency of the compressor in the current cycle. This indicates the operating frequency of the compressor in the previous cycle. It is a constant. This represents the first difference. This represents the second difference.

[0012] In some embodiments, after entering the rapid oil return mode, the control method further includes: When the opening time of the first solenoid valve is longer than the second preset time length, the rapid oil return mode is exited. Close the first electronic expansion valve and the first solenoid valve, and open the second electronic expansion valve and the second solenoid valve.

[0013] Thirdly, embodiments of this application also provide a computer-readable storage medium storing computer-executable instructions for performing the compressor oil return control method as described in the second aspect.

[0014] The compressor oil return control system, method, and medium according to the embodiments of this application have at least the following beneficial effects: by connecting the compressor's exhaust port to the inlet of the gas-liquid separator through a first electronic expansion valve, and connecting the compressor's suction port to the first outlet of the gas-liquid separator through a first solenoid valve, an oil return circuit independent of the air conditioner's heating / cooling circuit is formed. The system can control whether to drain oil from the gas-liquid separator by controlling the opening and closing of the first electronic expansion valve and the first solenoid valve. When a large amount of refrigerant oil accumulates at the bottom of the gas-liquid separator, the system can apply pressure to the inside of the gas-liquid separator through the compressor to drain the refrigerant oil at the bottom of the gas-liquid separator back to the compressor, thus avoiding oil shortage in the compressor.

[0015] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of a compressor oil return control system provided in one embodiment of this application; Figure 2 This is a flowchart of the steps of a compressor oil return control method provided in another embodiment of this application; Figure 3 This is a partial flowchart of a compressor oil return control method provided in another embodiment of this application; Figure 4 This is a partial flowchart of a compressor oil return control method provided in another embodiment of this application; Figure 5 This is a partial flowchart of a compressor oil return control method provided in another embodiment of this application; Figure 6 This is a partial flowchart of a compressor oil return control method provided in another embodiment of this application; Figure 7 This is a schematic diagram of the specific process of a compressor oil return control method provided in another embodiment of this application. Detailed Implementation

[0017] The embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. The step numbers in the following embodiments are set only for ease of explanation, and there is no limitation on the order between the steps. The execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0018] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 limiting this invention.

[0019] The terms "first," "second," "third," and "fourth," etc., used in the specification, claims, and accompanying drawings of this invention are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0020] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0021] To lubricate the compressor during operation, a certain amount of refrigerant oil is usually added to the refrigerant. However, during air conditioning operation, some refrigerant oil inevitably escapes from the compressor. When heating at low temperatures, the refrigerant oil tends to deposit at the bottom of the gas-liquid separator along with the liquid refrigerant, taking a relatively long time to return to the compressor. During this process, the compressor may experience oil shortage.

[0022] Although some air conditioning systems are equipped with oil separators, these are installed on the compressor's exhaust pipe and are responsible for recovering most of the high-temperature, high-pressure refrigerant oil discharged. The oil accumulation problem at the bottom of the gas-liquid separator occurs in the low-temperature, low-pressure section on the system's return gas side. Therefore, even with an efficient oil separator operating at the front end, oil accumulation at the bottom of the gas-liquid separator cannot be completely avoided during low-temperature heating.

[0023] Therefore, this application proposes a compressor oil return control system, method, and medium. By connecting the compressor's exhaust port to the inlet of the gas-liquid separator through a first electronic expansion valve, and connecting the compressor's suction port to the first outlet of the gas-liquid separator through a first solenoid valve, an oil return circuit independent of the air conditioner's heating / cooling circuit is formed. The system can control whether to drain oil from the gas-liquid separator by controlling the opening and closing of the first electronic expansion valve and the first solenoid valve. When a large amount of refrigerant oil accumulates at the bottom of the gas-liquid separator, the system can apply pressure to the inside of the gas-liquid separator through the compressor to drain the refrigerant oil at the bottom of the gas-liquid separator back to the compressor, thus avoiding oil shortage in the compressor.

[0024] The embodiments of this application will be further described below with reference to the accompanying drawings.

[0025] Firstly, embodiments of this application propose a compressor oil return control system, such as... Figure 1 As shown, the control system includes: a compressor 100, an oil separator 200, a multi-way valve 300, an indoor heat exchanger 400, an outdoor heat exchanger 500, and a gas-liquid separator 600. The discharge port of the compressor 100 is connected to the inlet of the oil separator 200. The first outlet of the oil separator 200 is connected to the suction port of the compressor 100 via an oil return pipe 210. The second outlet of the oil separator 200 is connected to the first end (D) of the multi-way valve 300. The second end (E) of the multi-way valve 300 is connected to one end of the indoor heat exchanger 400, and the other end of the indoor heat exchanger 400 is connected to one end of the outdoor heat exchanger 500. The other end of the outdoor heat exchanger 500 is connected to the third end (C) of the multi-way valve 300. The fourth end (S) of the multi-way valve is connected to the inlet of the gas-liquid separator 600 through the second solenoid valve 640. The inlet of the gas-liquid separator 600 is also connected to the exhaust port of the compressor 100 through the first electronic expansion valve 610. The first outlet of the gas-liquid separator 600 is connected to the suction port of the compressor 100 through the first solenoid valve 620. The second outlet of the gas-liquid separator 600 is connected to the suction port of the compressor 100 through the second electronic expansion valve 630. The first outlet of the gas-liquid separator 600 is located at the bottom of the gas-liquid separator 600.

[0026] It should be noted that, as Figure 1As shown, when the system is in heating mode, the first solenoid valve 620 and the first electronic expansion valve 610 are closed, and the second solenoid valve 640 and the second electronic expansion valve 630 are opened. The compressor 100 compresses the refrigerant to form a high-temperature, high-pressure gaseous refrigerant. This gaseous refrigerant, mixed with a small amount of refrigerant oil from the compressor 100, is discharged from the compressor 100's exhaust port and reaches the oil separator 200. In the oil separator 200, the refrigerant oil mixed with the gaseous refrigerant is separated through centrifugal separation, gravity sedimentation, etc. The separated refrigerant oil flows back to the crankcase of the compressor 100 via the oil return pipe 210 (to ensure lubrication). The high-temperature, high-pressure gaseous refrigerant after passing through the oil separator 200 passes through the first and second ends of the multi-way valve 300 and reaches the indoor heat exchanger 400. In the indoor heat exchanger 400, heat is exchanged with the indoor air, and the refrigerant releases heat and liquefies into a high-temperature, high-pressure liquid state. The indoor air is then heated and blown into the room. It should be noted that the indoor heat exchanger 400 is also equipped with an indoor fan 410 to assist in airflow and accelerate heating. A third electronic expansion valve 1200 can also be installed between the indoor heat exchanger 400 and the outdoor heat exchanger 500. The high-temperature, high-pressure liquid refrigerant generated by the indoor heat exchanger 400, after being throttled by the third electronic expansion valve 1200, becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, preparing for outdoor heat absorption. After entering the outdoor heat exchanger 500, the low-temperature, low-pressure gas-liquid two-phase refrigerant exchanges heat with the outdoor air, absorbing heat and evaporating into a low-temperature, low-pressure gaseous state (possibly containing a small amount of unevaporated liquid droplets). Simultaneously, the outdoor heat exchanger 500 is also equipped with an outdoor fan 510 to assist in airflow and accelerate heat absorption. Low-temperature, low-pressure gaseous refrigerant enters the gas-liquid separator 600 through the third and fourth ends of the multi-way valve 300. The gas-liquid separator 600 separates the liquid droplets, preventing liquid slugging in the compressor 100. Only the dry, low-temperature, low-pressure gaseous refrigerant enters the suction port of the compressor 100 to complete one heating cycle.

[0027] It should be noted that although the oil separator 200 can recover most of the refrigeration oil, a small amount of refrigeration oil will still flow with the refrigerant and eventually settle at the bottom of the gas-liquid separator 600, failing to be properly recovered to the compressor 100. When a large amount of refrigeration oil accumulates at the bottom of the gas-liquid separator 600, it will cause the compressor 100 to experience an oil shortage. Therefore, it is necessary to recover the refrigeration oil deposited at the bottom of the gas-liquid separator 600 into the compressor 100. To this end, this application provides an interconnecting pipeline between the exhaust port of the compressor 100 and the inlet of the gas-liquid separator 600. A first electronic expansion valve 610 is also installed on this pipeline. The first electronic expansion valve 610 controls the connection or disconnection between the exhaust port of the compressor 100 and the inlet of the gas-liquid separator 600. The degree of connection between the two can also be controlled by controlling the opening degree of the first electronic expansion valve 610. Meanwhile, a connecting pipeline is also provided between the first outlet of the gas-liquid separator 600 and the suction port of the compressor 100. A first solenoid valve 620 is installed on this pipeline, which can control the connection or disconnection between the first outlet of the gas-liquid separator 600 and the suction port of the compressor 100. When a large amount of refrigerant oil is deposited at the bottom of the gas-liquid separator 600, the second solenoid valve 640 and the second electronic expansion valve 630 are closed, and the first solenoid valve 620 and the first electronic expansion valve 610 are opened, allowing the compressor 100 to circulate air into the gas-liquid separator 600 through the exhaust port. The pressure is used to force the refrigerant oil deposited at the bottom of the gas-liquid separator 600 back into the compressor 100 from the first outlet of the gas-liquid separator 600.

[0028] Therefore, according to the compressor oil return control system of this application, by connecting the exhaust port of the compressor 100 to the inlet of the gas-liquid separator 600 through the first electronic expansion valve 610, and connecting the suction port of the compressor 100 to the first outlet of the gas-liquid separator 600 through the first solenoid valve 620, an oil return circuit independent of the heating / cooling circuit of the air conditioner is formed. The oil discharge from the gas-liquid separator 600 can be controlled by controlling the opening and closing of the first electronic expansion valve 610 and the first solenoid valve 620. When a lot of refrigerant oil accumulates at the bottom of the gas-liquid separator 600, the compressor 100 applies pressure to the inside of the gas-liquid separator 600 to discharge the refrigerant oil at the bottom of the gas-liquid separator 600 back to the compressor 100, thus avoiding the oil shortage situation of the compressor 100.

[0029] It should be noted that the compressor 100, oil separator 200, indoor heat exchanger 400, outdoor heat exchanger 500 and gas-liquid separator 600 are commonly used equipment in air conditioning systems, and their specific structures and working principles are well known to those skilled in the art. Therefore, the specific structures and working principles of the compressor 100, oil separator 200, indoor heat exchanger 400, outdoor heat exchanger 500 and gas-liquid separator 600 will not be described in detail here.

[0030] like Figure 1 As shown in some embodiments of this application, the oil return pipe 210 is equipped with an oil return temperature detection element 220. By setting the oil return temperature detection element 220, the temperature of the refrigerant oil sent back to the compressor 100 from the oil separator 200 can be monitored in real time, preventing damage to the compressor 100 due to excessively high oil return temperature. When the oil return temperature is too high, the oil return flow rate or operating status of the oil separator 200 can be adjusted to provide over-temperature protection for the compressor 100. It should be noted that the oil return temperature detection element 220 can be a temperature sensing bulb, a temperature sensor, or other devices with temperature detection functions.

[0031] like Figure 1 As shown in some embodiments of this application, the second outlet of the oil separator 200 is equipped with an exhaust temperature detection element 700 and a high-pressure sensor 800, the suction port of the compressor 100 is equipped with a suction temperature detection element 900, the inlet of the gas-liquid separator 600 is equipped with a low-pressure sensor 1000, and the bottom of the gas-liquid separator 600 is equipped with a bottom temperature detection element 1100. By setting the exhaust temperature detection element 700, the temperature of the refrigerant discharged from the compressor 100 can be obtained; by setting the suction temperature detection element 900, the temperature of the refrigerant absorbed by the compressor 100 can be obtained, providing a basis for protecting the compressor 100 and ensuring the normal operation of the system; by setting the bottom temperature detection element 1100, the deposition of refrigeration oil at the bottom of the gas-liquid separator 600 can be determined, allowing the system to determine whether oil drainage of the gas-liquid separator 600 is necessary. By setting the high-pressure sensor 800, the high-pressure refrigerant pressure on the discharge side of the compressor 100 can be obtained, and thus the condensation temperature of the refrigerant can be determined; by setting the low-pressure sensor 1000, the low-pressure refrigerant pressure at the inlet of the gas-liquid separator 600 can be obtained, and thus the evaporation temperature of the refrigerant can be determined.

[0032] like Figure 1 As shown, the indoor heat exchanger 400 is equipped with an indoor temperature detection element 420, and the outdoor heat exchanger 500 is equipped with an outdoor temperature detection element 520. The indoor temperature can be obtained through the indoor temperature detection element 420, and the outdoor temperature can be obtained through the outdoor temperature detection element 520, thus providing a reference for the system's cooling, heating, and oil return control processes.

[0033] The system's monitoring elements consist of return oil temperature detection element 220, exhaust temperature detection element 700, high pressure sensor 800, intake air temperature detection element 900, low pressure sensor 1000, bottom temperature detection element 1100, indoor temperature detection element 420, and outdoor temperature detection element 520. These elements facilitate the monitoring of various system parameters, providing reference for the system's operating status, mode switching, and the control of each device, thus ensuring the system's normal operation.

[0034] Secondly, based on the compressor oil return control system described in the first aspect embodiment above, this application also proposes a compressor oil return control method. This control method is applied to the controller of the control system, wherein the controller is electrically connected to the compressor 100, oil separator 200, gas-liquid separator 600, first electronic expansion valve 610, second electronic expansion valve 630, first solenoid valve 620, second solenoid valve 640, multi-way valve 300, indoor heat exchanger 400, and outdoor heat exchanger 500, respectively. The controller can control the working status of each device and the opening and closing status of each valve, thereby changing the working status and working mode of the entire system. Figure 2 As shown, the control method includes, but is not limited to, the following steps: Step S100: In heating mode, close the first electronic expansion valve 610 and the first solenoid valve 620, and open the second electronic expansion valve 630 and the second solenoid valve 640, so that the gas generated by the compressor 100 passes through the oil separator 200, the first and second ends of the multi-way valve 300, the indoor heat exchanger 400, the outdoor heat exchanger 500, the third and fourth ends of the multi-way valve 300, and the gas-liquid separator 600 in sequence, and then returns to the compressor 100; Step S200: Obtain the bottom temperature of the gas-liquid separator 600 and the first gas pressure at the inlet of the gas-liquid separator 600; Step S300: Determine the evaporation temperature of the refrigerant based on the first atmospheric pressure; Step S400: When the difference between the bottom temperature and the evaporation temperature is less than the first preset temperature and is maintained for the first preset time, enter the rapid oil return mode; Step S500: In the rapid oil return mode, open the first electronic expansion valve 610 and the first solenoid valve 620, close the second electronic expansion valve 630 and the second solenoid valve 640, and vent high pressure to the top of the gas-liquid separator 600 through the compressor 100, so that the refrigeration oil deposited at the bottom of the gas-liquid separator 600 returns to the compressor 100 through the pressure difference.

[0035] It should be noted that in heating mode, the system operates normally when there is no refrigerant oil deposition in the gas-liquid separator 600 or the amount of deposited refrigerant oil is small. During normal operation, the first electronic expansion valve 610 and the first solenoid valve 620 are closed, ensuring that the circuits between the compressor 100's discharge port and the gas-liquid separator 600's inlet, as well as between the gas-liquid separator 600's first outlet and the compressor 100's inlet, are both closed and non-conductive. Simultaneously, the second electronic expansion valve 630 and the second solenoid valve 640 are opened. In this state, the compressor 100 compresses the refrigerant, forming a high-temperature, high-pressure gaseous refrigerant. This gaseous refrigerant, carrying a small amount of refrigerant oil from the compressor 100, is discharged from the compressor 100's discharge port and reaches the oil separator 200. In the oil separator 200, the refrigerant oil mixed with the gaseous refrigerant is separated through centrifugal separation, gravity sedimentation, etc. The separated refrigerant oil flows back to the compressor 100's crankcase via the oil return pipe 210 (to ensure lubrication). After passing through the oil separator 200, the high-temperature, high-pressure gaseous refrigerant passes through the first and second ends of the multi-way valve 300 and reaches the indoor heat exchanger 400. In the indoor heat exchanger 400, it exchanges heat with the indoor air, releasing heat and liquefying into a high-temperature, high-pressure liquid state. The heated indoor air is then blown into the room. It should be noted that the indoor heat exchanger 400 is also equipped with an indoor fan 410 to assist in airflow and accelerate heating. A third electronic expansion valve 1200 can be installed between the indoor heat exchanger 400 and the outdoor heat exchanger 500. The high-temperature, high-pressure liquid refrigerant generated by the indoor heat exchanger 400 is throttled by the third electronic expansion valve 1200 and becomes a low-temperature, low-pressure gas-liquid two-phase refrigerant, preparing for outdoor heat absorption. After entering the outdoor heat exchanger 500, the low-temperature, low-pressure gas-liquid two-phase refrigerant exchanges heat with the outdoor air, absorbing heat and evaporating into a low-temperature, low-pressure gaseous state (possibly containing a small amount of unevaporated liquid droplets). At the same time, the outdoor heat exchanger 500 is also equipped with an outdoor fan 510 to assist in blowing air and accelerate heat absorption. The low-temperature, low-pressure gaseous refrigerant enters the gas-liquid separator 600 through the third and fourth ends of the multi-way valve 300. The gas-liquid separator 600 separates the liquid droplets, preventing liquid slugging in the compressor 100, allowing only the dry low-temperature, low-pressure gaseous refrigerant to enter the suction port of the compressor 100, completing one heating cycle.

[0036] It should be noted that although the oil separator 200 can recover most of the refrigeration oil, a small amount of refrigeration oil will still flow with the refrigerant and eventually settle at the bottom of the gas-liquid separator 600, which cannot be properly recovered to the compressor 100. When a lot of refrigeration oil settles at the bottom of the gas-liquid separator 600, it will cause the compressor 100 to run out of oil. Therefore, it is necessary to recover the refrigeration oil settled at the bottom of the gas-liquid separator 600 into the compressor 100.

[0037] To determine whether refrigerant oil has deposited at the bottom of the gas-liquid separator 600, this application includes a bottom temperature detection element 1100 at the bottom of the gas-liquid separator 600 and a low-pressure sensor 1000 at the inlet of the gas-liquid separator 600. The bottom temperature of the gas-liquid separator 600 can be obtained through the bottom temperature detection element 1100; the first pressure at the inlet of the gas-liquid separator 600 can be obtained through the low-pressure sensor 1000. Based on the first pressure, the evaporation temperature of the refrigerant can be determined. It should be noted that the saturation temperature, i.e., the evaporation temperature, of the refrigerant under different pressures can be determined by consulting the refrigerant's physical property parameter table. After obtaining the bottom temperature and the evaporation temperature, it is possible to determine whether refrigerant oil has deposited. The specific determination method is as follows: when T... 底部 -T 蒸发 If the temperature is <A℃ and remains below A℃ for B minutes, it indicates the presence of deposited refrigeration oil, requiring the activation of the rapid oil return mode. Where T... 底部 This indicates the bottom temperature of the gas-liquid separator 600, T. 蒸发 The evaporation temperature of the refrigerant is represented by A and B, which are constants. A corresponds to the first preset temperature, and its specific value can be set according to actual conditions, such as -3 to 0 degrees Celsius, or other reasonable values. B corresponds to the first preset time length, and its specific value can be set according to actual conditions, such as 60 to 120 degrees Celsius, or other reasonable values. After entering the rapid oil return mode, the second electronic expansion valve 630 and the second solenoid valve 640 are closed, and the first electronic expansion valve 610 and the first solenoid valve 620 are opened. At this time, the circuit between the exhaust port of the compressor 100 and the inlet of the gas-liquid separator 600, as well as the circuit between the first outlet of the gas-liquid separator 600 and the inlet of the compressor 100, are all in a connected state. At this time, the compressor 100 can vent air into the gas-liquid separator 600 through the exhaust port, and use pressure to force the refrigerant oil deposited at the bottom of the gas-liquid separator 600 back into the compressor 100 from the first outlet of the gas-liquid separator 600, thereby solving the problem of refrigerant oil deposited at the bottom of the gas-liquid separator 600.

[0038] Therefore, according to the compressor oil return control method of this application, by connecting the exhaust port of the compressor 100 to the inlet of the gas-liquid separator 600 through the first electronic expansion valve 610, and connecting the suction port of the compressor 100 to the first outlet of the gas-liquid separator 600 through the first solenoid valve 620, an oil return circuit independent of the heating / cooling circuit of the air conditioner is formed. The oil discharge from the gas-liquid separator 600 can be controlled by controlling the opening and closing of the first electronic expansion valve 610 and the first solenoid valve 620. When a lot of refrigerant oil is deposited at the bottom of the gas-liquid separator 600, the compressor 100 can apply pressure to the inside of the gas-liquid separator 600 to discharge the refrigerant oil at the bottom of the gas-liquid separator 600 back to the compressor 100, thus avoiding the oil shortage situation of the compressor 100.

[0039] like Figure 3 As shown, in some embodiments of this application, in the rapid oil return mode, the compressor oil return control method further includes the following steps: Step S510: Obtain the discharge temperature of compressor 100 and the second air pressure at the discharge port of compressor 100; Step S520: Determine the condensation temperature of the refrigerant based on the second atmospheric pressure; Step S530: Determine the opening degree of the first electronic expansion valve 610 in rapid oil return mode based on the exhaust temperature and condensation temperature; the opening degree is determined by the following formula: (1) in, This indicates the opening degree of the first electronic expansion valve 610 in the current cycle, in steps. The opening degree range can be set to a reasonable value such as 150-500 steps. The minimum opening degree after opening can be set to 150 steps. This indicates the opening degree of the first electronic expansion valve 610 in the previous cycle. And C is a constant. Indicates exhaust temperature. Indicates the condensation temperature.

[0040] It should be noted that, as Figure 1 As shown, in this example, an exhaust temperature detection element 700 and a high-pressure sensor 800 are installed at the second outlet of the oil separator 200. These can detect the exhaust temperature of the compressor 100 and the second gas pressure at the exhaust port. Based on the second gas pressure, the condensation temperature of the refrigerant can be determined. It should be noted that by consulting the refrigerant's physical property parameter table, the saturation temperature of the refrigerant at different gas pressures, i.e., the condensation temperature, can be obtained. After obtaining the exhaust temperature and condensation temperature, the opening degree of the first electronic expansion valve 610 in the rapid oil return mode can be determined. The opening degree of the first electronic expansion valve 610 is determined by equation (1). Equation (1) can introduce exhaust superheat as a control variable. The difference between the actual exhaust superheat and the target exhaust superheat is used as a proportional value to control the opening degree of the first electronic expansion valve 610. The greater the difference between the two, the smaller the opening degree, and the less high-temperature and high-pressure refrigerant enters the compressor 100. The purpose is to protect the compressor 100 and prevent the compressor 100 from burning out due to excessive exhaust superheat. The value of C can be set according to the actual situation, such as 5~10℃, or other reasonable values; the value of Y1 can be set according to the actual situation, such as 1~5 (unitless).

[0041] like Figure 4 As shown, in some embodiments of this application, after entering the rapid oil return mode, the compressor oil return control method further includes the following steps: Step S540: Obtain the suction temperature of compressor 100; Step S550: When the intake temperature is greater than the second preset temperature, open the second electronic expansion valve 630 and the second solenoid valve 640 until the intake temperature is less than the third preset temperature, then close the second electronic expansion valve 630 and the second solenoid valve 640; wherein the third preset temperature is less than the second preset temperature.

[0042] It should be noted that, as Figure 1 As shown, in this example, a suction temperature detection element 900 is provided at the suction port of the compressor 100. This suction temperature detection element 900 can be used to obtain the suction temperature of the compressor 100. For reliability reasons and to avoid damage to the compressor due to excessively high suction temperature, in this example, when the suction temperature T is detected... 吸气 >D℃, open the second electronic expansion valve 630 and the second solenoid valve 640 until the intake temperature T 吸气 <E℃, then close the second electronic expansion valve 630 and the second solenoid valve 640. It should be noted that D corresponds to the second preset temperature, and E corresponds to the third preset temperature. The values ​​of D and E can be adjusted according to actual conditions. For example, D can be set to 30~40, and E can be set to 20~28, or other reasonable values. When the intake temperature T... 吸气 When the temperature is >D℃, it indicates that the suction temperature is too high. By opening the second electronic expansion valve 630 and the second solenoid valve 640, low-temperature refrigerant is introduced to cool down the suction temperature, so that the suction temperature drops below the third preset temperature, ensuring the safety of the compressor 100.

[0043] The opening degree of the second electronic expansion valve 630 is determined in the following way: [X2 n ]=[X2 n-1 ]+Y3*(T 吸气 -D); (2) in, This indicates the opening degree of the second electronic expansion valve 630 in the current cycle, in steps. The opening degree range can be set to a reasonable value such as 150-500 steps. The minimum opening degree after opening can be set to 150 steps. This indicates the opening degree of the second electronic expansion valve 630 in the previous cycle. It is a constant. The value can be set according to the actual situation, such as 1~5 (no unit), or other reasonable values.

[0044] like Figure 5 As shown, in some embodiments of this application, after entering the rapid oil return mode, the compressor oil return control method further includes the following steps: Step S560: Obtain the first difference between the set temperature and the indoor temperature in the current cycle and the second difference in the previous cycle; Step S570: When the difference between the first difference and the second difference is greater than a preset value, the operating frequency of the compressor 100 is increased until the difference between the first difference and the second difference is less than or equal to 0 or the rapid oil return mode is exited; wherein, the operating frequency of the compressor 100 is determined by the following formula: (3) in, This indicates the operating frequency of compressor 100 in the current cycle, in rps, and can be set to 15~120 rps or other reasonable ranges. This indicates the operating frequency of compressor 100 in the previous cycle. It is a constant. Indicates the first difference. This represents the second difference.

[0045] It should be noted that T3 represents the set temperature T. 设定 With indoor temperature T 室内 The difference in the current cycle, T4 represents the set temperature T. 设定 With indoor temperature T 室内 The difference in the previous cycle. When entering the rapid oil return mode, when T3-T4>G℃, the operating frequency of compressor 100 is increased according to formula (3). When T3-T4≤0 or exiting the rapid oil return mode, compressor 100 stops increasing the frequency and resumes the original control. In this way, user comfort can be guaranteed. After entering the rapid oil return mode, when it is detected that the indoor ambient temperature has dropped significantly and affected the user's comfort, the frequency of compressor 100 is increased, thereby improving the heating efficiency of the indoor unit of the air conditioner and thus increasing the indoor temperature to ensure user comfort. Among them, G corresponds to the preset value. The value of G can be set according to the actual situation, such as 1~5, or other reasonable values. The specific value of Y2 can be set according to the actual situation, such as 1~5, etc.

[0046] like Figure 6 As shown, in some embodiments of this application, after entering the rapid oil return mode, the compressor oil return control method further includes the following steps: Step S580: When the opening time of the first solenoid valve 620 is longer than the second preset time length, exit the rapid oil return mode; Step S590: Close the first electronic expansion valve 610 and the first solenoid valve 620, and open the second electronic expansion valve 630 and the second solenoid valve 640.

[0047] It should be noted that after entering the rapid oil return mode, if the opening time of the first solenoid valve 620 reaches F minutes, the rapid oil return mode will exit, the first solenoid valve 620 and the first electronic expansion valve 610 will close, and the second electronic expansion valve 630 and the second solenoid valve 640 will be fully opened, restoring normal heating mode. This prevents the air conditioner from being in rapid oil return mode for an extended period, which could affect normal heating. Here, F corresponds to the second preset time length, and the value of F can be adjusted according to actual conditions, for example, set to 5~15 minutes, or other reasonable values.

[0048] The compressor oil return control method according to this application is specifically implemented as follows: Figure 7 As shown, by means of this method, when there is a deposit of refrigeration oil at the bottom of the gas-liquid separator 600 in the low-temperature heating mode, high-pressure exhaust can be introduced into the gas-liquid separator 600 in time to discharge the deposited refrigeration oil back into the gas-liquid separator 600, replenish the compressor 100 with refrigeration oil, and avoid the compressor 100 from running out of oil.

[0049] Thirdly, embodiments of this application also provide a storage medium, which is a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described compressor oil return control method.

[0050] Memory, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, memory may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, memory may optionally include memory remotely located relative to the processor, and these remote memories can be connected to the processor via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof. The device embodiments described above are merely illustrative, and the units described as separate components may or may not be physically separate, and may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0051] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically include computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0052] The above provides a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A compressor oil return control system, characterized in that, The control system includes: compressor; An oil separator, wherein the inlet of the oil separator is connected to the exhaust port of the compressor, and the first outlet of the oil separator is connected to the suction port of the compressor through an oil return pipe; A multi-way valve, wherein the first end of the multi-way valve is connected to the second outlet of the oil separator; An indoor heat exchanger, one end of which is connected to the second end of the multi-way valve; An outdoor heat exchanger, one end of which is connected to the other end of the indoor heat exchanger, and the other end of the outdoor heat exchanger is connected to the third end of the multi-way valve. The gas-liquid separator has an inlet connected to the exhaust port of the compressor via a first electronic expansion valve, a first outlet connected to the suction port of the compressor via a first solenoid valve, a second outlet connected to the suction port of the compressor via a second electronic expansion valve, and an inlet also connected to the fourth end of the multi-way valve via a second solenoid valve. The first outlet of the gas-liquid separator is located at the bottom of the gas-liquid separator.

2. The compressor oil return control system according to claim 1, characterized in that, The return oil pipe is equipped with a return oil temperature detection element.

3. The compressor oil return control system according to claim 1, characterized in that, The second outlet of the oil separator is equipped with an exhaust temperature detection element and a high-pressure sensor, the suction port of the compressor is equipped with a suction temperature detection element, the inlet of the gas-liquid separator is equipped with a low-pressure sensor, and the bottom of the gas-liquid separator is equipped with a bottom temperature detection element.

4. The compressor oil return control system according to claim 1, characterized in that, The indoor heat exchanger is equipped with an indoor temperature detection element, the outdoor heat exchanger is equipped with an outdoor temperature detection element, and a third electronic expansion valve is installed between the indoor heat exchanger and the outdoor heat exchanger.

5. A compressor oil return control method, characterized in that, A controller applied to the compressor oil return control system as described in any one of claims 1-4, wherein the controller is electrically connected to the compressor, the oil separator, the multi-way valve, the gas-liquid separator, the first electronic expansion valve, the first solenoid valve, the second electronic expansion valve, the second solenoid valve, the indoor heat exchanger, and the outdoor heat exchanger, respectively; the control method includes: In heating mode, the first electronic expansion valve and the first solenoid valve are closed, and the second electronic expansion valve and the second solenoid valve are opened, so that the refrigerant output by the compressor passes sequentially through the oil separator, the first and second ends of the multi-way valve, the indoor heat exchanger, the outdoor heat exchanger, the third and fourth ends of the multi-way valve, and the gas-liquid separator before returning to the compressor. The bottom temperature of the gas-liquid separator and the first gas pressure at the inlet of the gas-liquid separator are obtained; Determine the evaporation temperature of the refrigerant based on the first air pressure; When the difference between the bottom temperature and the evaporation temperature is less than the first preset temperature and remains so for the first preset time, the system enters the rapid oil return mode. In the rapid oil return mode, the first electronic expansion valve and the first solenoid valve are opened, and the second electronic expansion valve and the second solenoid valve are closed. High-pressure gas is supplied to the top of the gas-liquid separator through the compressor, and the refrigerant oil deposited at the bottom of the gas-liquid separator is returned to the compressor through the pressure difference.

6. The compressor oil return control method according to claim 5, characterized in that, In the rapid oil return mode, the control method further includes: The discharge temperature of the compressor and the second air pressure at the discharge port of the compressor are obtained; The condensation temperature of the refrigerant is determined based on the second gas pressure. The opening degree of the first electronic expansion valve in rapid oil return mode is determined based on the exhaust temperature and the condensation temperature; the opening degree is determined by the following formula: ； in, This indicates the opening degree of the first electronic expansion valve in the current cycle. This indicates the opening degree of the first electronic expansion valve in the previous cycle. And C is a constant. This indicates the exhaust temperature. This indicates the condensation temperature.

7. The compressor oil return control method according to claim 5, characterized in that, After entering the rapid oil return mode, the control method further includes: Obtain the suction temperature of the compressor; When the intake temperature is greater than the second preset temperature, the second electronic expansion valve and the second solenoid valve are opened until the intake temperature is less than the third preset temperature, at which point the second electronic expansion valve and the second solenoid valve are closed; wherein the third preset temperature is less than the second preset temperature.

8. The compressor oil return control method according to claim 5, characterized in that, After entering the rapid oil return mode, the control method further includes: Get the first difference between the set temperature and the indoor temperature in the current cycle and the second difference in the previous cycle; When the difference between the first difference and the second difference is greater than a preset value, the operating frequency of the compressor is increased until the difference between the first difference and the second difference is less than or equal to 0 or the rapid oil return mode is exited; wherein, the operating frequency of the compressor is determined by the following formula: ； in, This indicates the operating frequency of the compressor in the current cycle. This indicates the operating frequency of the compressor in the previous cycle. It is a constant. This represents the first difference. This represents the second difference.

9. The compressor oil return control method according to claim 5, characterized in that, After entering the rapid oil return mode, the control method further includes: When the opening time of the first solenoid valve is longer than the second preset time length, the rapid oil return mode is exited. Close the first electronic expansion valve and the first solenoid valve, and open the second electronic expansion valve and the second solenoid valve.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions for causing a computer to perform the compressor oil return control method as described in any one of claims 5 to 9.

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