Refrigerant circulation control system and air conditioning equipment

Abstract

The utility model provides a refrigerant circulation control system and air conditioning equipment, and relates to the technical field of air conditioners, a first circulation branch, a compressor and an oil separator form a first circulation loop, and a second circulation branch and a refrigerant circulation main path form a second circulation loop; when the first control valve is opened, and the electronic expansion valve and the second control valve are closed, a refrigerant in the refrigerant circulation control system circulates through the first circulation loop, and preheating of the compressor is achieved; when the first control valve, the electronic expansion valve and the second control valve are opened, refrigerants circulate through the first circulation loop and the second circulation loop so as to gradually drive the whole system refrigerants to circulate after preheating of the compressor is completed, the situation that a large amount of liquid refrigerants enter a compression cavity of the compressor in a short time is reduced, and the low-temperature starting liquid return risk of the compressor is reduced; when the first control valve is closed, and the electronic expansion valve and the second control valve are both opened, the refrigerant in the refrigerant circulation control system circulates through the second circulation loop, and energy conservation and emission reduction are achieved.

Description

Technical Field

[0001] This application relates to the field of air conditioning technology, and in particular to a refrigerant circulation control system and air conditioning equipment. Background Technology

[0002] Currently, multi-split air conditioning systems are widely used in many fields due to their numerous advantages and ability to meet the needs of different scenarios. However, because multi-split systems are typically larger, they require a correspondingly larger amount of refrigerant, which significantly increases the risk of refrigerant backflow in the air conditioning compressor, especially when used in cold regions where the backflow is more severe.

[0003] To mitigate the refrigerant return problem in air conditioning compressors, the commonly used method is to add an oil heating belt to the compressor. Before starting at low temperatures, the oil heating belt heats the refrigerant and oil at the bottom of the compressor, thereby reducing the risk of refrigerant return during the low-temperature start-up process.

[0004] However, the existing oil heating belt preheating scheme has too long a preheating time, and the oil heating belt must be kept working normally at low temperatures, resulting in a lot of energy waste and is not conducive to energy conservation and emission reduction. Summary of the Invention

[0005] In view of this, this application provides a refrigerant circulation control system and air conditioning equipment to solve the problem of resource waste caused by using oil heating belt preheating to alleviate the refrigerant return during air conditioning compressor startup in the prior art.

[0006] According to a first aspect of the embodiments of this application, a refrigerant circulation control system is provided, including: a refrigerant circulation main circuit, a first circulation branch circuit, and a second circulation branch circuit;

[0007] A first control valve is installed on the first circulation branch; an electronic expansion valve is installed on the second circulation branch; a compressor, an oil separator, a second control valve, and a vapor-liquid separator are installed on the main refrigerant circulation line.

[0008] The inlet of the first circulation branch is connected between the outlet of the oil separator and the second control valve; the inlet of the second circulation branch is connected to the outlet of the vapor-liquid separator, and the outlet of the first circulation branch, the outlet of the second circulation branch, and the inlet of the compressor are connected; the first circulation branch, the compressor, and the oil separator constitute a first circulation loop, and the second circulation branch and the refrigerant circulation main line constitute a second circulation loop.

[0009] When the first control valve is open and the electronic expansion valve and the second control valve are closed, the refrigerant in the refrigerant circulation control system circulates through the first circulation loop;

[0010] When the first control valve, the electronic expansion valve, and the second control valve are all open, the refrigerant in the refrigerant circulation control system circulates through the first circulation loop and the second circulation loop.

[0011] When the first control valve is closed and both the electronic expansion valve and the second control valve are open, the refrigerant in the refrigerant circulation control system circulates through the second circulation loop.

[0012] In an optional embodiment, the second circulation branch is further provided with a first check valve, the inlet of which is connected to the outlet of the electronic expansion valve, and the outlet of which is connected to the outlet of the first circulation branch and the inlet of the compressor.

[0013] In an optional embodiment, the refrigerant circulation control system further includes a control device; the control device is electrically connected to the first control valve, the second control valve, and the electronic expansion valve, respectively.

[0014] The control device is used to control the refrigerant circulation control system to enter the target start-up mode based on the ambient temperature detection information, and to determine the current exhaust superheat based on the compressor's exhaust pressure and exhaust temperature, so as to control the start-up and operation status of the refrigerant circulation control system according to the current exhaust superheat and the opening degree of the electronic expansion valve.

[0015] In an optional implementation, the main refrigerant circulation circuit is also equipped with a pressure sensor and an exhaust temperature sensor. The pressure sensor is used to detect the compressor's exhaust pressure, and the exhaust temperature sensor is used to detect the compressor's exhaust temperature. The control device is also used to adjust the opening of the electronic expansion valve according to the current exhaust superheat.

[0016] In one optional implementation, the ambient temperature detection information includes the ambient temperature and the corresponding downtime.

[0017] An ambient temperature sensor is installed between the second control valve and the inlet of the vapor-liquid separator in the main refrigerant circulation path; the ambient temperature sensor is used to detect the ambient temperature.

[0018] The step of controlling the refrigerant circulation control system to enter the target start-up mode based on ambient temperature detection information includes: determining that the ambient temperature detection information meets the preset mode triggering conditions when the ambient temperature is lower than the preset temperature threshold corresponding to the target start-up mode and the shutdown time reaches the preset shutdown duration threshold corresponding to the temperature threshold; and controlling the refrigerant circulation control system to enter the first operating stage of the target start-up mode when the ambient temperature detection information meets the preset mode triggering conditions.

[0019] In one optional embodiment, the refrigerant circulation main line is provided with a first heat exchanger between the second control valve and the inlet of the vapor-liquid separator, and the inlet of the first heat exchanger is connected to the outlet of the second control valve.

[0020] In an optional embodiment, the refrigerant circulation main line is further provided with a first valve, which is located between the outlet of the first heat exchanger and the inlet of the vapor-liquid separator.

[0021] In an optional embodiment, the refrigerant circulation main circuit is further provided with a second valve and a second heat exchanger;

[0022] The second heat exchanger is disposed between the outlet of the first valve and the inlet of the second valve, and the outlet of the second valve is connected to the inlet of the vapor-liquid separator.

[0023] In an optional embodiment, the first circulation branch is further provided with a second check valve, the inlet of which is connected to the outlet of the first control valve, and the outlet of which is connected to the inlet of the compressor.

[0024] According to a second aspect of the embodiments of this application, an air conditioning device is provided, the air conditioning device including a refrigerant circulation control system as described in any of the first aspects.

[0025] The technical solutions provided by the embodiments of this application may include the following beneficial effects: In this application, the refrigerant circulation control system includes a refrigerant circulation main circuit, a first circulation branch circuit, and a second circulation branch circuit. The first circulation branch circuit, together with the compressor and the oil separator, forms a first circulation loop, and the second circulation branch circuit, together with the refrigerant circulation main circuit, forms a second circulation loop. When the compressor starts, by acquiring ambient temperature detection information, and when the ambient temperature detection information meets the preset mode triggering conditions, the refrigerant circulation control system is controlled to enter the first operating stage of the target start-up mode, so that the refrigerant in the refrigerant circulation control system circulates through the first circulation loop. Based on the compressor's discharge pressure and discharge temperature, the current discharge superheat is determined, so that when the current discharge superheat meets the second stage triggering conditions, the refrigerant is controlled. The second operating stage of the refrigerant circulation control system enters the target start-up mode, causing the refrigerant in the refrigerant circulation control system to circulate through the first and second circulation loops. The opening of the electronic expansion valve is adjusted according to the current exhaust superheat. When the electronic expansion valve is fully open and the current exhaust superheat is greater than the preset first heat threshold, the system exits the target start-up mode and controls the refrigerant to circulate through the second circulation loop. This allows the refrigerant to circulate through the first circulation loop when the compressor starts, achieving compressor preheating. After the compressor is preheated, the refrigerant circulation of the entire system is gradually driven. This can effectively reduce the large amount of liquid refrigerant entering the compressor compression chamber in a short time, reduce the risk of liquid return during low-temperature compressor start-up, and replace the electric heating preheating scheme used in existing related technologies, achieving energy saving and emission reduction.

[0026] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0027] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0029] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0030] Figure 1This is a schematic diagram of a refrigerant circulation control system according to an exemplary embodiment;

[0031] Figure 2 This is a schematic diagram illustrating refrigerant circulation through a first circulation loop according to an exemplary embodiment;

[0032] Figure 3 This is a schematic diagram illustrating refrigerant circulation through a first circulation loop and a second circulation loop according to an exemplary embodiment;

[0033] Figure 4 This is a schematic diagram illustrating refrigerant circulation via a second circulation loop according to an exemplary embodiment;

[0034] Figure 5 This is a structural block diagram of a refrigerant circulation control system according to an exemplary embodiment;

[0035] Figure 6 This is a schematic flowchart illustrating a refrigerant circulation control method according to an exemplary embodiment;

[0036] Figure 7 This is a structural block diagram of an air conditioning device according to an exemplary embodiment.

[0037] Figure label:

[0038] 100. Refrigerant circulation control system; 110. Refrigerant circulation main circuit; 111. Compressor; 112. Oil separator; 113. Second control valve; 114. Vapor-liquid separator; 115. First valve; 116. Second valve; 117. First electronic expansion valve; 118. Ambient temperature sensor; 120. First circulation branch; 121. First control valve; 122. Second check valve; 130. Second circulation branch; 140. Control device; 131. Electronic expansion valve; 132. First check valve; 41. Pressure sensor; 42. Exhaust temperature sensor; 43. Intake temperature sensor; 44. First heat exchanger; 45. Fan; 46. Second heat exchanger; 47. Centrifugal fan; 700. Air conditioning equipment. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0040] The following disclosure provides numerous different embodiments or examples for implementing various aspects of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0041] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0042] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0043] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0044] Currently, multi-split air conditioning systems have a large refrigerant charge, leading to significant issues with liquid refrigerant return during low-temperature startup. Specifically, when the air conditioning unit is started in a low-temperature environment, a large amount of refrigerant enters the compressor due to the low temperature. This means that liquid refrigerant enters the compressor's compression chamber at startup, increasing the load and potentially causing the compression chamber to rupture due to the incompressibility of liquids. Therefore, controlling the entry of liquid refrigerant into the compression chamber is crucial.

[0045] To address the resource waste caused by the use of oil heating elements for preheating in existing technologies to mitigate the liquid return during compressor startup, this application provides a refrigerant circulation control system and air conditioning equipment. This system incorporates additional components to create a new refrigerant circulation control system. By adding branch pipes (referred to as the first circulation branch) with these additional components, a new circulation loop with a smaller refrigerant volume (referred to as the first circulation loop) is constructed. During low-temperature startup, the refrigerant circulates through this first circulation loop. Once the compressor is preheated, the entire system's refrigerant circulation is gradually initiated. This effectively reduces the large amount of liquid refrigerant entering the compressor's compression chamber in a short time, lowers the risk of liquid return during low-temperature compressor startup, and can replace the electric heating preheating scheme used in existing related technologies, reducing energy consumption and achieving energy conservation and emission reduction.

[0046] The refrigerant circulation control system 100 in this application includes: a main refrigerant circulation path 110, a first circulation branch path 120, and a second circulation branch path 130, as follows: Figure 1As shown, a first control valve 121 is provided on the first circulation branch 120, an electronic expansion valve 131 is provided on the second circulation branch 130, and a compressor 111, an oil separator 112, a second control valve 113, and a vapor-liquid separator 114 are provided on the refrigerant circulation main line 110. The inlet of the first circulation branch 120 is connected between the outlet of the oil separator 112 and the inlet of the second control valve 113, and the inlet of the second circulation branch 130 is connected to the outlet of the vapor-liquid separator 114. The outlets of the first circulation branch 120, the second circulation branch 130, and the compressor 111 are connected. The first circulation branch 120, the compressor 111, and the oil separator 112 constitute a first circulation loop, and the second circulation branch 130 and the refrigerant circulation main line 110 constitute a second circulation loop. During low-temperature startup, such as when compressor 111 starts, by acquiring ambient temperature detection information, if the ambient temperature detection information meets the low-temperature startup mode conditions (referred to as the preset mode trigger condition), the system directly enters the low-temperature startup mode (referred to as the target startup mode). At this time, the first control valve 121 is opened, and the electronic expansion valve 131 and the second control valve 113 are closed, so that the refrigerant circulates through the first circulation loop. After compressor 111 is fully preheated, the refrigerant circulates through the first circulation loop and the second circulation loop, thereby effectively reducing the large amount of liquid refrigerant entering the compressor 111 compression chamber in a short time and reducing the risk of liquid return during low-temperature startup of compressor 111.

[0047] In one exemplary embodiment of this application, a refrigerant circulation control system 100 is provided, along with a refrigerant circulation control method and a refrigerant circulation control device applied to the aforementioned refrigerant circulation control system 100, and an air conditioning device including the aforementioned refrigerant circulation control system 100. (Reference) Figure 1 As shown, the refrigerant circulation control system 100 may include: a refrigerant circulation main line 110, a first circulation branch line 120, and a second circulation branch line 130; a first control valve 121 is provided on the first circulation branch line 120, and an electronic expansion valve 131 is provided on the second circulation branch line 130. A compressor 111, an oil separator 112, a second control valve 113, and a vapor-liquid separator 114 are provided on the refrigerant circulation main line 110. The inlet of the first circulation branch line 120 is connected between the outlet of the oil separator 112 and the inlet of the second control valve 113, and the inlet of the second circulation branch line 130 is connected to the outlet of the vapor-liquid separator 114. The outlets of the first circulation branch line 120, the second circulation branch line 130, and the inlet of the compressor 111 are connected. The first circulation branch line 120, the compressor 111, and the oil separator 112 constitute a first circulation loop, and the second circulation branch line 130 and the refrigerant circulation main line 110 constitute a second circulation loop.

[0048] The first control valve 121 and the second control valve 113 can be solenoid valves. For example, the first control valve 121 is a first solenoid valve, which is configured to open the first circulation branch 120 when the refrigerant circulation control system 100 enters the target start-up mode; or the second control valve 113 is a second solenoid valve, which is configured to close the second circulation loop when the refrigerant circulation control system 100 enters the first stage of the target start-up mode. The embodiments of this application do not specifically limit the types of the first control valve 121 and the second control valve 113.

[0049] In this application, when the first control valve 121 is open and the electronic expansion valve 131 and the second control valve 113 are closed, the refrigerant in the refrigerant circulation control system 100 circulates through the first circulation loop, such as... Figure 2 As shown; when the first control valve 121, the electronic expansion valve 131, and the second control valve 113 are all open, the refrigerant in the refrigerant circulation control system 100 circulates through the first circulation loop and the second circulation loop, as shown. Figure 3 As shown; when the first control valve 121 is closed, and both the electronic expansion valve 131 and the second control valve 113 are open, the refrigerant in the refrigerant circulation control system 100 circulates through the second circulation loop, as shown. Figure 4 As shown.

[0050] As can be seen, the electronic expansion valve 131 in this embodiment can be used to shut off the second circulation branch 130 to disconnect the second circulation loop, that is, the refrigerant in the refrigerant circulation control system 100 does not circulate through the second circulation loop. In this way, a new circulation system with a small amount of refrigerant can be constructed using the first circulation loop. After the compressor 111 has finished preheating, the refrigerant circulation of the entire system is gradually driven through the first and second circulation loops. This can effectively reduce the large amount of liquid refrigerant entering the compressor 111 compression chamber in a short time and reduce the risk of liquid return during low-temperature start-up of the compressor 111.

[0051] In some optional embodiments of this application, the second circulation branch 130 is further provided with a first one-way valve 132, so that the refrigerant flowing out of the first circulation branch 120 cannot be delivered to the vapor-liquid separator 114 through the second circulation branch 130. The outlet of the first circulation branch 120 is connected to the inlet of the compressor 111, and all the refrigerant flowing out of the first circulation branch 120 flows into the compressor 111 cavity. For example, the first one-way valve 132 can be set between the vapor-liquid separator 114 and the electronic expansion valve 131, or it can be set between the outlet of the second circulation branch 130 and the electronic expansion valve 131. This application embodiment does not limit this.

[0052] As an example of this application, such as Figure 1 As shown, the inlet of the first one-way valve 132 is connected to the outlet of the electronic expansion valve 131, and the outlet of the first one-way valve 132 is connected to the outlet of the first circulation branch 120 and the inlet of the compressor 111, so that the refrigerant flowing out of the first circulation branch 120 cannot be delivered to the electronic expansion valve 131 and the vapor-liquid separator 114 through the second circulation branch 130. Alternatively, the inlet of the first one-way valve 132 is connected to the outlet of the electronic expansion valve 131, and the outlet of the first one-way valve 132 is connected to the inlet of the compressor 111. Optionally, the outlet of the first one-way valve 132 is connected to the outlet of the first circulation branch 120 and the inlet of the compressor 111, so that the refrigerant flowing out of the first circulation branch 120 cannot be delivered to the electronic expansion valve 131 and the vapor-liquid separator 114 through the second circulation branch 130.

[0053] Of course, the first circulation branch 120 in this application example can also be equipped with a one-way valve (denoted as the second one-way valve 122), so that the refrigerant flowing out of the second circulation branch 130 cannot be delivered to the second control valve 113 and the oil separator 112 through the first circulation branch 120, and is connected to the inlet of the compressor 111 through the outlet of the second circulation branch 130, so that all the refrigerant flowing out of the second circulation branch 130 flows into the compressor 111 cavity. For example, as Figure 4 As shown, the second check valve 122 on the first circulation branch 120 can be set between the first control valve 121 and the outlet of the first circulation branch 120; specifically, the inlet of the second check valve 122 is connected to the outlet of the first control valve 121, and the outlet of the second check valve 122 is connected to the inlet of the compressor 111. Optionally, the outlet of the second check valve 122 is connected to the outlet of the first circulation branch 120 and the inlet of the compressor 111, so that the refrigerant flowing out from the second circulation branch 130 cannot be delivered to the first control valve 121 through the first circulation branch 120.

[0054] Optional, such as Figure 5As shown, the refrigerant circulation control system 100 in this application may further include a control device 140, with the first control valve 121, the second control valve 113, and the electronic expansion valve 131 electrically connected to the control device 140. The control device 140 may use a programmable logic controller (PLC) as its core control unit. It may integrate multiple sensor interfaces, including the suction pressure sensor interface, discharge pressure sensor interface, temperature sensor interface, and current sensor interface of the compressor 111, etc., enabling it to collect various operating parameters of the refrigerant circulation control system 100 in real time. This allows the control device 140 to control the refrigerant circulation control system 100 to enter the target start-up mode based on ambient temperature detection information, and to determine the current discharge superheat based on the discharge pressure and discharge temperature of the compressor 111, thereby controlling the start-up and operation state of the refrigerant circulation control system 100 according to the current discharge superheat and the opening degree of the electronic expansion valve 131. The temperature sensor interface may include the discharge temperature sensor interface of the compressor 111, the ambient temperature sensor interface, the suction temperature sensor interface of the vapor-liquid separator 114, etc., and this application embodiment does not impose any limitations on this.

[0055] In this embodiment, the control device is used to, when the compressor 111 is started, control the refrigerant circulation control system 100 to enter a target start-up mode based on ambient temperature detection information, and determine the current exhaust superheat based on the exhaust pressure and exhaust temperature of the compressor 111, so as to control the start-up operation state of the refrigerant circulation control system 100 according to the current exhaust superheat and the opening degree of the electronic expansion valve 131. When the compressor 111 is detected to be started and the ambient temperature detection information meets the preset mode triggering conditions, the first control valve 121 is opened and the electronic expansion valve 131 and the second control valve 113 are closed, so as to control the refrigerant circulation control system 100 to enter the first operating stage of the target start-up mode, so that the refrigerant circulates through the first circulation loop. The target start-up mode is a low-temperature start-up mode. The first operating stage of the target start-up mode is used to control the refrigerant in the refrigerant circulation control system 100 to circulate through the first circulation loop. The electronic expansion valve 131 is configured to shut off the second circulation branch 130 when the refrigerant circulation system enters the first stage of the target start-up mode, so as to disconnect the second circulation loop and allow the refrigerant to circulate through the first circulation loop, so that the refrigerant circulation system circulates with a smaller amount of refrigerant, thereby preheating the compressor 111.

[0056] The control device can store a dedicated control algorithm program. During the startup process of the compressor 111, based on the data fed back by the sensors, it accurately determines the startup and operation status of the refrigerant circulation control system 100 and promptly issues control commands to control the opening and closing of the first control valve 121, the second control valve 113, and the electronic expansion valve 131. For example, it determines the current exhaust superheat based on the exhaust pressure and exhaust temperature of the compressor 111, and adjusts the opening degree of the electronic expansion valve 131 according to the current exhaust superheat when the electronic expansion valve 131 is open, so as to gradually adjust the refrigerant circulation control system 100 after the compressor 111 has finished preheating. The system first initiates refrigerant circulation throughout the entire system. When the electronic expansion valve 131 is fully open and the current exhaust superheat exceeds a preset first thermal threshold, the system exits the target start-up mode. This involves closing the first control valve 121, allowing the refrigerant circulation control system 100 to enter the third stage of start-up operation. This enables refrigerant circulation through the second circulation loop, allowing for a more efficient allocation of refrigerant circulation volume. Refrigerant first circulates within the first circulation loop, using a portion of the refrigerant to preheat the compressor 111. Once the compressor is fully preheated, the entire system's refrigerant circulation is gradually initiated, thus reducing the risk of liquid return during low-temperature start-up of the compressor 111. The third stage of start-up operation controls the refrigerant circulation through the second circulation loop, ensuring the system operates normally as required.

[0057] Optionally, the ambient temperature detection information in this application includes the ambient temperature and the corresponding shutdown time. An ambient temperature sensing element 118 is installed between the inlet of the second control valve 113 and the vapor-liquid separator 114 in the refrigerant circulation main circuit 110. The ambient temperature sensing element 118 is used to detect the ambient temperature. The control device controls the refrigerant circulation control system to enter the target start-up mode based on the ambient temperature detection information. Specifically, this may include: when the ambient temperature is lower than the preset temperature threshold corresponding to the target start-up mode, and the shutdown time reaches the preset shutdown duration threshold corresponding to the temperature threshold, determining that the ambient temperature detection information meets the preset mode triggering condition, so that when the ambient temperature detection information meets the preset mode triggering condition, the refrigerant circulation control system 100 is controlled to enter the first operating stage of the target start-up mode, thereby allowing the refrigerant to circulate through the first circulation loop to achieve compressor preheating.

[0058] Of course, in addition to compressor 111, oil separator 112, second control valve 113, vapor-liquid separator 114 and ambient temperature sensor 118, refrigerant circulation main circuit 110 can also be equipped with other devices, such as first valve 115, second valve 116, first electronic expansion valve 117, pressure sensor 41, exhaust temperature sensor 42, intake temperature sensor 43, heat exchanger, etc. This application embodiment does not make specific limitations in this regard.

[0059] Optionally, the refrigerant circulation main line 110 is provided with a first heat exchanger 44 between the second control valve 113 and the inlet of the vapor-liquid separator 114, and the inlet of the first heat exchanger 44 is connected to the outlet of the second control valve.

[0060] Optionally, the refrigerant circulation main line 110 may also be equipped with a first valve 115, which is located between the outlet of the first heat exchanger 44 and the inlet of the vapor-liquid separator 114.

[0061] Optionally, the refrigerant circulation main line 110 is further provided with a second valve 116 and a second heat exchanger 46; the second heat exchanger 46 is disposed between the outlet of the first valve 115 and the inlet of the second valve 116, and the outlet of the second valve 116 is connected to the inlet of the vapor-liquid separator 114.

[0062] Optionally, the refrigerant circulation main circuit 110 in this embodiment is further equipped with a pressure sensor 41 and an exhaust temperature sensor 42; the pressure sensor 41 is used to detect the exhaust pressure of the compressor 111, and the exhaust temperature sensor 42 is used to detect the exhaust temperature of the compressor 111, so that the control device can determine the current exhaust superheat based on the exhaust pressure and exhaust temperature of the compressor 111, and control the start-up and operation state of the refrigerant circulation control system 100 according to the current exhaust superheat and the opening degree of the electronic expansion valve 131. Optionally, the control device in this embodiment is also used to adjust the opening degree of the electronic expansion valve 131 according to the current exhaust superheat.

[0063] In some alternative embodiments of this application, the pressure sensor 41 may be a high-pressure sensor, for example, such as... Figure 3 As shown, pressure sensor 41 can be installed between the exhaust port of compressor 111 and exhaust temperature sensing bulb 42. This pressure sensor 41 is configured to detect the exhaust pressure of compressor 111, allowing the refrigerant circulation control system 100 to determine the current exhaust superheat based on the exhaust pressure of compressor 111 and the exhaust temperature detected by exhaust temperature sensing bulb 42. Therefore, if the current exhaust superheat meets the second stage triggering conditions, the electronic expansion valve 131 can be opened to control the refrigerant circulation control system 100 to enter the second operating stage of the target start-up mode, allowing the refrigerant to circulate through the second circulation loop and the first circulation loop. Figure 3As shown, the opening of the electronic expansion valve 131 is adjusted according to the current exhaust superheat. The start-up and operation status of the refrigerant circulation control system 100 is controlled according to the current exhaust superheat and the opening of the electronic expansion valve 131. For example, when the electronic expansion valve 131 is fully open and the current exhaust superheat is greater than the preset first heat threshold, the first control valve 121 is closed, that is, the first circulation loop is disconnected and the target start-up mode is exited. The refrigerant circulation control system 100 is then controlled to enter the third stage of start-up and operation, so that the refrigerant circulates through the second circulation loop, and the refrigerant circulation can be controlled as needed.

[0064] The preset first heat threshold is negatively correlated with the ambient temperature. For example, the lower the ambient temperature, the higher the preset first heat threshold. Its main function is to prevent the compressor 111 from being worn due to excessive discharge of lubricating oil. For example, the preset first heat threshold can be set to 5°C. When the electronic expansion valve 131 is fully open and the current exhaust superheat Δ is greater than 5°C, that is, when Δ>5°C, the refrigerant circulation control system 100 is triggered to exit the low-temperature start-up mode and enter the third stage of start-up operation. The third stage of start-up operation is used to control the refrigerant to circulate through the second circulation loop, that is, the electronic expansion valve 131 is fully open, the second control valve 113 is open, and the first control valve 121 is closed, so that the system is controlled normally according to the requirements.

[0065] As can be seen, the refrigerant circulation main line 110 in this embodiment can also be equipped with a heat exchanger, a first valve 115, a second valve 116, and a first electronic expansion valve 117; wherein, the heat exchanger can be divided into a first heat exchanger 44 disposed between the second control valve 113 and the first valve 115 and a second heat exchanger 46 disposed between the first electronic expansion valve 117 and the second valve 116, and a fan 45 can be disposed on one side of the first heat exchanger 44 to form an evaporator in the refrigerant circulation main line 110; the first electronic expansion valve 117 is disposed between the first valve 115 and the second heat exchanger 46. 7. The refrigerant flowing to the second heat exchanger 46 is controlled by the first electronic expansion valve 117, and a centrifugal fan 47 can be provided on one side of the second heat exchanger 46 to form a condenser in the refrigerant circulation main circuit 110 through the second heat exchanger and the centrifugal fan 47. The second valve 116 can be provided between the inlet of the second heat exchanger 47 and the vapor-liquid separator 114 to control the refrigerant flowing to the vapor-liquid separator 114. Thus, the refrigerant circulation control system 100 can control the amount of refrigerant circulating in the second circulation loop through the refrigerant circulation main circuit 110 to meet the refrigerant circulation requirements.

[0066] In one exemplary embodiment, a refrigerant circulation control method is provided, applied to the aforementioned refrigerant circulation control system 100, as the control method for the aforementioned refrigerant circulation control system 100, with reference to... Figures 1 to 4As shown, in the refrigerant circulation control system 100, during the low-temperature start-up process of the compressor 111, due to the low temperature, a large amount of liquid refrigerant may enter the compression chamber of the compressor 111 in a short period of time, which may increase the wear and tear on the compressor 111 or even damage the compressor 111 and affect its service life.

[0067] In this embodiment, such as Figure 6 As shown, the refrigerant circulation control method acquires ambient temperature detection information when the compressor is started. It then determines whether the ambient temperature detection information meets the low-temperature start-up mode conditions (denoted as the preset mode trigger condition). If the ambient temperature detection information meets the preset mode trigger condition, the refrigerant circulation control system 100 is controlled to enter the first operating stage of the target start-up mode. The current exhaust superheat is determined based on the compressor's exhaust pressure and exhaust temperature. Here, the current exhaust superheat refers to the current exhaust superheat of the compressor 111; the ambient temperature detection information can refer to information detected regarding the ambient temperature, specifically including the detected ambient temperature and the shutdown time of the compressor 111 in the system. This embodiment does not impose any limitations on this. The first operating stage is used to control the refrigerant in the refrigerant circulation control system 100 to circulate through the first circulation loop.

[0068] In some optional embodiments of this application, a preset temperature value A (denoted as a preset temperature threshold) can be set in advance for the low-temperature start-up mode (denoted as the target start-up mode), and a corresponding shutdown time threshold B (denoted as a preset shutdown duration threshold) can be set for the preset temperature threshold A. When the unit in the refrigerant circulation control system 100 starts, such as when the compressor 111 starts, it is determined whether the ambient temperature is lower than the preset temperature threshold A and whether the shutdown time corresponding to the ambient temperature is greater than the shutdown time threshold B. This determines whether the current ambient temperature detection information meets the preset mode triggering conditions. Thus, if the detected ambient temperature is lower than the preset temperature threshold A and the shutdown time corresponding to the ambient temperature is greater than the preset shutdown duration threshold B corresponding to the temperature threshold A, it is considered that the ambient temperature detection information meets the preset mode triggering conditions.

[0069] Optionally, in this embodiment of the application, when the ambient temperature detection information meets the preset mode triggering conditions, the refrigerant circulation control system 100 is controlled to enter the first operating stage of the target start-up mode. Specifically, this may include: when the ambient temperature is less than the preset temperature threshold corresponding to the target start-up mode, and the shutdown time reaches the preset shutdown duration threshold corresponding to the temperature threshold, determining that the ambient temperature detection information meets the preset mode triggering conditions, and controlling the first control valve to open and the second control valve to close, so as to control the refrigerant circulation control system 100 to enter the first operating stage.

[0070] For example, if the refrigerant circulation control system 100 detects that the ambient temperature is lower than a preset temperature threshold A, and the shutdown time is greater than the preset shutdown duration threshold B corresponding to temperature threshold A, then when the unit starts, it directly enters the low-temperature start-up mode (denoted as the target start-up mode). The preset temperature threshold A and the shutdown duration threshold B have a corresponding relationship. For example, the value ranges of temperature threshold A and its corresponding shutdown duration threshold B are shown in Table 1. This application embodiment does not impose specific restrictions on the specific values ​​of temperature threshold A and shutdown duration threshold B.

[0071] AB 1 hour 2 hours 3 hours -10℃ Do not enter Do not enter Enter -20℃ Do not enter Enter Enter -30℃ Enter Enter Enter

[0072] Table 1

[0073] When the refrigerant circulation control system 100 enters the low-temperature start-up mode, in the first stage of the low-temperature start-up mode (referred to as the first operating stage of the target start-up mode), the electronic expansion valve 131 is closed, the second control valve 113 is closed, and the first control valve 121 is open, allowing the refrigerant in the refrigerant circulation control system 100 to circulate through the first circulation loop. That is, the refrigerant circulation control system 100 circulates the refrigerant through the first circulation loop. Figure 2 As shown, the first circulation loop consists of a compressor 111, a pressure sensor 41, an exhaust temperature sensing bulb 42, an oil separator 112, and a first control valve 121, forming a new small refrigerant circulation system to preheat the compressor 111.

[0074] Furthermore, during the first stage of the low-temperature start-up mode, the refrigerant circulation control system 100 controls the compressor 111 to operate at a low frequency (denoted as the preset initial start-up frequency). For example, the preset initial start-up frequency can be 10Hz, meaning that during the first operating stage of the target start-up mode, the compressor 111 can operate at a low frequency of 10Hz. The system can also determine the current exhaust superheat based on the compressor's exhaust pressure and temperature. If the current exhaust superheat meets the triggering conditions for the second stage, the refrigerant circulation control system 100 is controlled to enter the second stage of the low-temperature start-up mode (denoted as the second operating stage of the target start-up mode). This second operating stage controls the refrigerant to circulate through the first and second circulation loops, gradually driving the refrigerant circulation throughout the system. This effectively reduces the large amount of liquid refrigerant entering the compressor's compression chamber in a short time, lowering the risk of liquid return during low-temperature compressor start-up.

[0075] Optionally, in the first operating stage of the target start-up mode, the refrigerant circulation control method provided in this application embodiment further includes: controlling the compressor to operate at a preset initial start-up frequency to achieve low-frequency preheating of the compressor.

[0076] In some optional embodiments of this application, after determining the current exhaust superheat based on the compressor's exhaust pressure and exhaust temperature, the refrigerant circulation control method further includes the following steps:

[0077] Step S11: Compare the current exhaust superheat with a preset second heat threshold.

[0078] Step S12: If the current exhaust superheat is not less than the second heat threshold, determine that the current exhaust superheat meets the second stage triggering condition.

[0079] Specifically, after determining the current exhaust superheat based on the compressor's exhaust pressure and temperature, the control device in the refrigerant circulation control system 100 can compare the current exhaust superheat with a preset second heat threshold. If the current exhaust superheat is not less than the second heat threshold (e.g., if the current exhaust superheat is denoted as Δ and the preset second heat threshold is denoted as Δ1), and Δ≥Δ1, then the current exhaust superheat meets the second stage trigger condition. At this time, the electronic expansion valve and the second control valve are opened to control the refrigerant circulation control system 100 to enter the second operating stage of the target start-up mode, allowing the refrigerant to circulate through the first and second circulation loops. Figure 3 As shown, the opening degree of the electronic expansion valve 131 at this time is related to the current exhaust superheat. The second operating stage controls the refrigerant circulation through the first and second circulation loops; the preset second heat threshold Δ1 can be set according to the ambient temperature to prevent excessive lubricating oil discharge, thereby solving the compressor wear problem caused by excessive lubricating oil discharge and extending the compressor's service life.

[0080] For example, with the initial opening of the electronic expansion valve 131 being 50 steps, and taking a full load of 480 steps as an example, the opening of the electronic expansion valve 131 can be adjusted according to the electronic expansion valve opening calculation formula K = 50 * Δ / Δ1 until the electronic expansion valve 131 is fully open and the exhaust superheat Δ is greater than the preset first heat threshold. Then, the target start-up mode is exited, i.e., the first control valve 121 is closed, thereby controlling the refrigerant circulation control system 100 to enter the third stage of start-up operation, allowing the refrigerant to circulate through the second circulation loop. All calculation parameters in the electronic expansion valve opening calculation formula are examples; the maximum value of K is 480. This application embodiment does not limit the specific values ​​of the calculation parameters.

[0081] As can be seen, in this embodiment of the application, when the current exhaust superheat meets the second stage triggering condition, the refrigerant circulation control system 100 is controlled to enter the second operating stage of the target start-up mode, and the opening of the electronic expansion valve is adjusted according to the current exhaust superheat. When the electronic expansion valve is fully open and the current exhaust superheat is greater than the preset first heat threshold, the target start-up mode is exited, so as to control the refrigerant circulation control system 100 to enter the third stage of start-up operation, so that the system is controlled normally according to the requirements.

[0082] Optionally, in this embodiment of the application, the current exhaust superheat is determined based on the compressor's exhaust pressure and exhaust temperature. Specifically, this may include: detecting the compressor's exhaust pressure using a pressure sensor in the refrigerant circulation control system 100 and determining the saturation temperature corresponding to the exhaust pressure; detecting the compressor's exhaust temperature using an exhaust temperature sensor in the refrigerant circulation control system 100; and calculating the current exhaust superheat based on the exhaust temperature and saturation temperature.

[0083] For example, when the pressure sensor 41 in the refrigerant circulation control system 100 is a high-pressure sensor, after detecting the exhaust pressure through the high-pressure sensor, the saturation temperature corresponding to the high exhaust pressure (denoted as the saturation temperature corresponding to the exhaust pressure) can be determined using the exhaust pressure. Based on this saturation temperature and the exhaust temperature, calculations can be performed, such as using the exhaust superheat calculation formula Δ = exhaust temperature - saturation temperature corresponding to the high exhaust pressure. The current exhaust superheat Δ is obtained by using the saturation temperature and the exhaust temperature. When the current exhaust superheat Δ meets the second stage triggering condition, the refrigerant circulation control system 100 is controlled to enter the second operating stage of the target start-up mode. The opening of the electronic expansion valve 131 is adjusted according to the current exhaust superheat. Then, when the electronic expansion valve 131 is fully open and the current exhaust superheat is greater than the preset first heat threshold, the target start-up mode is exited, that is, the first control valve 121 is closed, so as to control the refrigerant circulation control system 100 to enter the third stage of start-up operation.

[0084] Of course, in the case of the fully open electronic expansion valve 131, in addition to determining whether to exit the target start-up mode by judging whether the current exhaust superheat is greater than the preset first heat threshold, other methods can also be used to determine whether to exit the target start-up mode and enter the third stage of start-up operation. This application embodiment does not impose specific restrictions on this.

[0085] In some optional embodiments of this application, after the refrigerant circulation control method controls the refrigerant circulation control system 100 to enter the second operating stage of the target start-up mode, it may further include: when the electronic expansion valve is fully open and the current exhaust superheat is not greater than a preset first heat threshold, adjusting the operating frequency of the compressor to a preset first operating frequency, and the first operating frequency is higher than the initial start-up frequency; controlling the compressor to operate according to the first operating frequency until the refrigerant circulation control system 100 exits the target start-up mode.

[0086] For example, if the preset first heat threshold is 5°C, and the electronic expansion valve is fully open and the current exhaust superheat Δ≤5°C, adjusting the operating frequency of compressor 111 to the preset first operating frequency will increase the exhaust superheat of the compressor. This continues until the refrigerant circulation control system 100 exits the target start-up mode and enters the third stage of start-up operation. Then, the operating frequency of compressor 111 is controlled according to system requirements to achieve energy saving and emission reduction. The preset first operating frequency is system-related and primarily functions to increase exhaust superheat. It can be set according to system parameters, but the preset first operating frequency should not be set too high to prevent excessive pressure difference during mode switching, which would hinder control. It should be noted that system parameters refer to parameters in the refrigerant circulation control system 100, specifically including hardware parameters and / or software control parameters. This application embodiment does not limit this.

[0087] Of course, after entering the first operating stage of the target start-up mode, this application embodiment can determine whether to control the refrigerant circulation control system 100 to enter the second operating stage of the target start-up mode by judging whether the current exhaust superheat meets the second stage triggering condition. Other methods can also be used to determine whether to enter the second operating stage of the target start-up mode. For example, it can determine whether to enter the second operating stage of the target start-up mode by judging whether the current operating frequency of the compressor (denoted as the current operating frequency) reaches the preset second operating frequency. This application embodiment does not impose specific limitations on this.

[0088] The preset second operating frequency is related to the system and its main function is to increase the exhaust superheat. It can be set according to the system parameters to increase the compressor's exhaust superheat by increasing the compressor's operating frequency. However, the preset second operating parameter should not be set too high to prevent the pressure difference from being too large during mode switching, which would be detrimental to control.

[0089] Optionally, after the refrigerant circulation control method described above controls the refrigerant circulation control system 100 to enter the first operating stage of the target start-up mode, it may further include: detecting the current operating frequency of the compressor; when the current operating frequency reaches a preset second operating frequency and the current exhaust superheat is less than a preset second heat threshold, controlling the second control valve and the electronic expansion valve to open, so as to control the refrigerant circulation control system 100 to enter the second operating stage of the target start-up mode, and controlling the compressor to operate according to the current operating frequency, wherein the second operating frequency is higher than the first operating frequency.

[0090] For example, if the preset second heat threshold is denoted as △1 and the current exhaust superheat is denoted as △, if the first stage of the target start-up mode continuously detects △<△1, it can be determined whether the current operating frequency of the compressor 111 is increased to the preset second operating frequency. If the compressor 111 is increased to the preset second operating frequency, the second control valve 113 and the electronic expansion valve 131 can be controlled to open until the second operating stage is entered. The operating frequency of the compressor 111 in the first operating stage can be extended to the second operating stage, so that the compressor 111 operates according to the preset second operating frequency, ensuring that the exhaust superheat of the compressor 111 is high enough to meet the system control requirements.

[0091] In one exemplary embodiment, a refrigerant circulation control device is provided, applied to the aforementioned refrigerant circulation control system 100, and can serve as the control device for the aforementioned refrigerant circulation control system 100, such as... Figure 6As shown, the refrigerant circulation control system 100100 may include a control device 610 and the refrigerant circulation main circuit 110, first circulation branch circuit 120, and second circulation branch circuit 130 as described in any of the above embodiments. The connection relationship between the control device 160 and other components in the refrigerant circulation control system 100100 can be referred to in the above embodiments and will not be repeated here. The control device 610 is configured to implement the refrigerant circulation control method as described in any of the above embodiments. When the compressor is started, it acquires ambient temperature detection information and determines whether the ambient temperature detection information meets the low-temperature start-up mode conditions (denoted as the preset mode trigger condition). If the ambient temperature detection information meets the preset mode trigger condition, it controls the refrigerant circulation control system 100 to enter the first operating stage of the target start-up mode, so that the refrigerant circulates through the first circulation loop to preheat the compressor. Based on the compressor's discharge pressure and discharge temperature, it determines the current discharge superheat. If the current discharge superheat meets the second stage trigger condition, it controls the refrigerant circulation control system 100 to enter the first operating stage of the target start-up mode. The system 100 enters the second operating stage of the target start-up mode, allowing the refrigerant to circulate through the first and second circulation loops after the compressor has been preheated. The opening of the electronic expansion valve is adjusted according to the current exhaust superheat to gradually drive the refrigerant circulation of the entire system. This effectively reduces the large amount of liquid refrigerant entering the compressor compression chamber in a short period of time, lowers the risk of liquid return during low-temperature compressor start-up, and exits the target start-up mode when the electronic expansion valve is fully open and the current exhaust superheat is greater than the preset first heat threshold. This allows the refrigerant circulation control system 100 to enter the third stage of start-up operation, where the refrigerant circulates through the second circulation loop to be controlled according to demand, achieving energy saving and emission reduction.

[0092] In a specific implementation, the refrigerant circulation control system 100 described in any of the above embodiments can be integrated into an air conditioning unit. This allows the air conditioning unit to acquire ambient temperature detection information when the compressor starts, and if the ambient temperature detection information meets the preset mode triggering conditions, control the refrigerant circulation control system 100 to enter the first operating stage of the target start-up mode. This allows the refrigerant to circulate through the first circulation loop, preheating the compressor. Subsequently, based on the compressor's discharge pressure and discharge temperature, the current discharge superheat is determined. If the current discharge superheat meets the second stage triggering conditions, the refrigerant circulation control system 100 is then controlled to enter the target start-up mode. In the second operating phase, after the refrigerant has been preheated by the compressor, it circulates through the first and second circulation loops. The opening of the electronic expansion valve is adjusted according to the current exhaust superheat to gradually drive the refrigerant circulation throughout the system. This effectively reduces the large amount of liquid refrigerant entering the compressor compression chamber in a short period of time, lowers the risk of liquid return during low-temperature compressor start-up, and exits the target start-up mode when the electronic expansion valve is fully open and the current exhaust superheat is greater than the preset first temperature threshold. This allows the refrigerant circulation control system 100 to enter the third stage of start-up operation, where the refrigerant circulates through the second circulation loop, thus enabling control as needed and achieving energy saving and emission reduction.

[0093] like Figure 7 As shown in the figure, this application embodiment also provides an air conditioning device 700, which includes the refrigerant circulation control system 100 described in any of the above embodiments. This allows the air conditioning device to circulate refrigerant through the first circulation loop in the refrigerant circulation control system 100 when starting at low temperatures, thereby preheating the compressor. After the compressor is preheated, the refrigerant circulation of the entire system is gradually driven, thereby effectively reducing the large amount of liquid refrigerant entering the compressor compression chamber in a short time, reducing the risk of liquid return during low-temperature start-up of the compressor, extending the service life of the compressor, and reducing energy consumption to achieve energy saving and emission reduction.

[0094] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0095] It should be noted that the terms "one implementation," "embodiment," "exemplary embodiment," and "some embodiments" used in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0096] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0097] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A refrigerant circulation control system, characterized in that, include: The refrigerant circulation main circuit, the first circulation branch circuit, and the second circulation branch circuit; A first control valve is installed on the first circulation branch; an electronic expansion valve is installed on the second circulation branch; The refrigerant circulation main circuit is equipped with a compressor, an oil separator, a second control valve, and a vapor-liquid separator; The inlet of the first circulation branch is connected between the outlet of the oil separator and the second control valve; the inlet of the second circulation branch is connected to the outlet of the vapor-liquid separator, and the outlet of the first circulation branch, the outlet of the second circulation branch, and the inlet of the compressor are connected; the first circulation branch, the compressor, and the oil separator constitute a first circulation loop, and the second circulation branch and the refrigerant circulation main line constitute a second circulation loop. When the first control valve is open and the electronic expansion valve and the second control valve are closed, the refrigerant in the refrigerant circulation control system circulates through the first circulation loop; When the first control valve, the electronic expansion valve, and the second control valve are all open, the refrigerant in the refrigerant circulation control system circulates through the first circulation loop and the second circulation loop. When the first control valve is closed and both the electronic expansion valve and the second control valve are open, the refrigerant in the refrigerant circulation control system circulates through the second circulation loop.

2. The refrigerant circulation control system according to claim 1, characterized in that, The second circulation branch is also provided with a first one-way valve. The inlet of the first one-way valve is connected to the outlet of the electronic expansion valve, and the outlet of the first one-way valve is connected to the outlet of the first circulation branch and the inlet of the compressor.

3. The refrigerant circulation control system according to claim 1, characterized in that, Also includes: A control device, which is electrically connected to the first control valve, the second control valve and the electronic expansion valve respectively; The control device is used to, when the compressor is started, control the refrigerant circulation control system to enter the target start-up mode based on the ambient temperature detection information, and determine the current exhaust superheat based on the exhaust pressure and exhaust temperature of the compressor, so as to control the start-up and operation status of the refrigerant circulation control system according to the current exhaust superheat and the opening degree of the electronic expansion valve.

4. The refrigerant circulation control system according to claim 3, characterized in that, The main refrigerant circulation circuit is also equipped with a pressure sensor and an exhaust temperature sensor. The pressure sensor is used to detect the discharge pressure of the compressor; The exhaust temperature sensor is used to detect the exhaust temperature of the compressor. The control device is also used to adjust the opening of the electronic expansion valve according to the current exhaust superheat.

5. The refrigerant circulation control system according to claim 3, characterized in that, The ambient temperature detection information includes the ambient temperature and the corresponding downtime. An ambient temperature sensor is installed between the second control valve and the inlet of the vapor-liquid separator in the main refrigerant circulation path. The ambient temperature sensing bulb is used to detect the ambient temperature; The step of controlling the refrigerant circulation control system to enter the target start-up mode based on ambient temperature detection information includes: when the ambient temperature is less than the preset temperature threshold corresponding to the target start-up mode, and the shutdown time reaches the preset shutdown duration threshold corresponding to the temperature threshold, determining that the ambient temperature detection information meets the preset mode triggering conditions. When the ambient temperature detection information meets the preset mode triggering conditions, the refrigerant circulation control system is controlled to enter the first operating stage of the target start-up mode.

6. The refrigerant circulation system according to claim 1, characterized in that, The refrigerant circulation main circuit has a first heat exchanger installed between the second control valve and the inlet of the vapor-liquid separator, and the inlet of the first heat exchanger is connected to the outlet of the second control valve.

7. The refrigerant circulation system according to claim 6, characterized in that, The main refrigerant circulation path is also equipped with a first valve, which is located between the outlet of the first heat exchanger and the inlet of the vapor-liquid separator.

8. The refrigerant circulation system according to claim 7, characterized in that, The main refrigerant circulation path is also equipped with a second valve and a second heat exchanger; The second heat exchanger is disposed between the outlet of the first valve and the inlet of the second valve, and the outlet of the second valve is connected to the inlet of the vapor-liquid separator.

9. The refrigerant circulation system according to any one of claims 1 to 8, characterized in that, The first circulation branch is also provided with a second check valve, the inlet of which is connected to the outlet of the first control valve, and the outlet of which is connected to the inlet of the compressor.

10. An air conditioning device, characterized in that, The air conditioning equipment includes a refrigerant circulation control system as described in any one of claims 1 to 9.

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