Compressor system, multi-connected air conditioner, control method and device for compressor oil return

Abstract

The application relates to the technical field of air conditioning equipment, and discloses a compressor system, which comprises a compressor and an oil separator, the inlet end of the oil separator is connected with the exhaust side of the compressor, further comprises an oil return flow path, the oil return flow path comprises a throttling communication assembly and a gas-liquid separator which are connected in sequence through pipelines, the inlet end of the oil return flow path is connected with the oil outlet end of the oil separator, the oil return hole of the gas-liquid separator is connected with the suction side of the compressor through the outlet end of the oil return flow path, a current detection assembly is configured to detect the current value of the compressor, and a controller is configured to control the throttling communication assembly to make the oil return flow path communicate or be cut off according to the detection result of the current detection assembly; in the case that the oil return flow path is cut off, unnecessary oil return actions can be avoided, and system capacity loss caused by the communication between the high-pressure side and the low-pressure side can be avoided. The application further discloses a multi-connected air conditioner and a control method and device for compressor oil return.

Description

Technical Field

[0001] This application relates to the field of air conditioning equipment technology, such as a compressor system, a multi-split air conditioner, and a control method and device for compressor oil return. Background Technology

[0002] Currently, due to the long piping of multi-split air conditioners, compressor oil, once discharged with the refrigerant, does not easily return, potentially leading to compressor oil shortage and damage. To prevent compressor oil from being discharged with the refrigerant, multi-split air conditioners are equipped with an oil separator to separate the refrigerant from the compressor oil.

[0003] In order to ensure that the oil from the oil separator returns to the compressor, the existing technology uses a capillary tube connecting the bottom of the oil separator and the low-pressure side of the system. This allows the separated oil to return to the suction side of the compressor under the pressure difference between the high and low pressure, and eventually return to the compressor. It then circulates locally without entering the indoor unit or other pipelines far away from the compressor.

[0004] In the process of implementing the embodiments of this disclosure, at least the following problems were found in the related art:

[0005] Because the efficiency of the oil separator is not stable, and the separation of oil and refrigerant requires a certain flow rate, when the oil separator has no oil left, due to the fixed specifications of the capillary tube, the high and low pressure sides are connected, and the refrigerant will be directly unloaded to the low pressure side, causing the refrigerant to be unable to participate in the system circulation, resulting in a loss of capacity. Summary of the Invention

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0007] This disclosure provides a compressor system, a multi-split air conditioner, and a control method and apparatus for compressor oil return, to avoid system capacity loss during the oil return process.

[0008] In some embodiments, the compressor system includes a compressor and an oil separator, wherein the inlet end of the oil separator is connected to the discharge side of the compressor; it further includes: an oil return path, comprising a throttling connection component and a gas-liquid separator connected in sequence via pipelines; the inlet end of the oil return path is connected to the oil outlet end of the oil separator; the oil return port of the gas-liquid separator is connected to the suction side of the compressor through the outlet end of the oil return path; a current detection component is configured to detect the current value of the compressor; and a controller is configured to control the throttling connection component to open or close the oil return path based on the detection result of the current detection component.

[0009] Optionally, the compressor system further includes:

[0010] A temperature detection component is used to detect the first temperature of the fluid in the return oil flow path before passing through the throttling and connecting component and the second temperature after passing through the throttling and connecting component;

[0011] The controller is also configured to control the throttling connection component to connect or disconnect the return oil flow path based on the detection results of the current detection component and the detection results of the temperature detection component.

[0012] Optionally, the temperature detection component includes: a pre-throttling temperature sensor disposed between the throttling connection component and the compressor; and a post-throttling temperature sensor disposed between the throttling connection component and the gas-liquid separator.

[0013] Optionally, the return oil flow path further includes a filter disposed between the inlet end of the return oil flow path and the throttling connection component.

[0014] Optionally, the throttling connection component includes an electronic expansion valve.

[0015] In some embodiments, the multi-split air conditioner includes the compressor system described above.

[0016] In some embodiments, the control method for compressor oil return, applied to the above-mentioned multi-split air conditioner, includes: obtaining the current value of the compressor when the oil return path is connected;

[0017] Based on the current value range satisfied by the current value, a control strategy for the throttling connection component is determined so that the return oil flow path remains connected or disconnected.

[0018] Optionally, if the current value is greater than a first current threshold, a control strategy for the throttling connectivity component is determined, including:

[0019] Control the throttling connection component to cut off the return oil flow path;

[0020] If the current value is less than or equal to the first current threshold, a control strategy for the throttling connectivity component is determined, including:

[0021] The first temperature of the fluid in the return oil flow path before passing through the throttling and connecting component and the second temperature after passing through the throttling and connecting component are obtained.

[0022] Based on the current temperature difference between the first temperature and the second temperature, a control strategy for the throttling connection component is determined.

[0023] Optionally, obtaining the first current threshold includes:

[0024] Obtain the correspondence between compressor frequency, compressor oil status, and compressor current;

[0025] Obtain the current frequency of the compressor, and determine the compressor current corresponding to the current frequency when the compressor is full of oil as the first preset current;

[0026] The first current threshold is determined based on the first preset current; the first preset current is greater than the first current threshold.

[0027] Optionally, determining the control strategy for the throttling connectivity component based on the current temperature difference between the first temperature and the second temperature includes:

[0028] If the current temperature difference is greater than the first temperature difference, the control strategy for the throttling and connecting component includes:

[0029] Close the throttling connection component at the current opening degree to cut off the return oil flow path;

[0030] If the current temperature difference is less than or equal to the second temperature difference, the control strategy for the throttling and connecting component includes:

[0031] Increase the opening of the throttling connection component to keep the return oil flow path connected and increase the return oil volume;

[0032] Wherein, the first temperature difference is greater than the second temperature difference.

[0033] Optionally, increasing the opening degree of the throttling connectivity component includes:

[0034] The opening adjustment value for increasing the opening degree of the throttling connection component is determined based on the current current value;

[0035] The sum of the current opening degree and the opening degree adjustment value is determined as the target opening degree, and the throttling connection component is controlled to increase to the target opening degree adjustment at a set rate.

[0036] Optionally, determining the opening adjustment value for increasing the opening degree of the throttling connection component based on the current current value includes:

[0037] If the current value is greater than the second current threshold, then the opening adjustment value is determined as the first opening adjustment value;

[0038] If the current current value is less than or equal to the second current threshold, then the opening adjustment value is determined as the second opening adjustment value;

[0039] Wherein, the second current threshold is less than the first current threshold; and the first opening adjustment value is greater than the second opening adjustment value.

[0040] Optionally, obtaining the second current threshold includes:

[0041] Obtain the correspondence between compressor frequency, compressor oil status, and compressor current;

[0042] Obtain the current frequency of the compressor, and determine the compressor current corresponding to the non-full oil state of the compressor at the current frequency as the second preset current;

[0043] The second current threshold is determined based on the second preset current; the second preset current is greater than the second current threshold.

[0044] The non-full oil state includes both the oil shortage state and the oil supply state; the second preset current is greater than the first preset current.

[0045] Optionally, the above-mentioned compressor oil return control method further includes:

[0046] The interval duration for controlling the connection of the oil return path is determined based on the operating frequency of the compressor; the operating frequency of the compressor is negatively correlated with the interval duration.

[0047] In some embodiments, the compressor oil return control device, applied in the above-described multi-split air conditioner, includes a processor and a memory storing program instructions. The processor is configured to execute the above-described control method for compressor oil return when running the program instructions.

[0048] The compressor system, multi-split air conditioner, and control method and apparatus for compressor oil return provided in this disclosure can achieve the following technical effects:

[0049] By detecting the compressor's current value, the oil condition of the compressor is determined, and the throttling connection component installed on the oil return path is controlled to either open or close the oil return path. In this way, when the oil return path is open, the compressor oil can return to the compressor's suction side through the oil return port of the gas-liquid separator, preventing compressor wear caused by oil shortage. When the oil return path is closed, unnecessary oil return actions are avoided, preventing system capacity loss caused by connecting the high and low pressure sides.

[0050] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0051] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0052] Figure 1 This is a schematic diagram of the connection structure of a compressor system in related technologies;

[0053] Figure 2a This disclosure provides a connection diagram of a compressor system according to an embodiment;

[0054] Figure 2b yes Figure 2a Schematic diagram of controller connection for the medium compressor system;

[0055] Figure 3a Another connection diagram of a compressor system provided in this disclosure embodiment;

[0056] Figure 3b yes Figure 3a Schematic diagram of controller connection for the medium compressor system;

[0057] Figure 4a This is a connection diagram of a multi-split air conditioner provided in an embodiment of this disclosure;

[0058] Figure 4b yes Figure 4a Schematic diagram of controller connection for a multi-split air conditioner;

[0059] Figure 5 This is a schematic flowchart of a control method for compressor oil return provided in an embodiment of this disclosure;

[0060] Figure 6 This is a schematic flowchart of another control method for compressor oil return provided in an embodiment of this disclosure;

[0061] Figure 7 This is a schematic flowchart of another control method for compressor oil return provided in an embodiment of this disclosure;

[0062] Figure 8 This is a schematic diagram of a control device for compressor oil return provided in an embodiment of this disclosure. Detailed Implementation

[0063] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be simplified in their depiction to simplify the drawings.

[0064] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0065] Unless otherwise stated, the term "multiple" means two or more.

[0066] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0067] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0068] The term "correspondence" can refer to an association or binding relationship. The correspondence between A and B means that there is an association or binding relationship between A and B.

[0069] Figure 1 This is a schematic diagram of the connection structure of a compressor system in related technologies.

[0070] As shown in Figure 1, the oil return path of the compressor system is formed by sequentially connecting the compressor 110, oil separator 120, capillary tube 130, and gas-liquid separator 140; the oil outlet end of the oil separator 120 is connected to the inlet end of the capillary tube 130; and the refrigerant outlet end of the oil separator 120 is connected to the refrigeration cycle system.

[0071] Here, a capillary tube connects the bottom of the oil separator to the inlet end (low-pressure side) of the gas-liquid separator. The separated compressor oil returns to the compressor suction side under the action of the high and low pressure difference, directly returning to the compressor for local circulation, instead of entering the indoor unit or other pipelines far away from the compressor.

[0072] Because the specifications of the capillary tube installed in the system cannot be changed, it is impossible to accommodate all operating conditions. At the same time, since the separation of compressor oil and refrigerant requires a certain flow rate, the efficiency of the oil separator is relatively low when the compressor is running at low frequency. Because the separation of oil and refrigerant requires a certain flow rate, the oil separator does not separate any oil at this time. Due to the fixed specifications of the capillary tube, the high and low pressure are connected, and the refrigerant will be directly unloaded to the low-pressure side, causing the refrigerant to be unable to participate in the system circulation, resulting in a loss of capacity.

[0073] Therefore, this proposal suggests a new compressor system to improve the oil return process through structural improvements and control strategies.

[0074] Figure 2a This is a connection diagram of a compressor system provided in an embodiment of this disclosure. Figure 2b This is a schematic diagram of the controller connection for the compressor system.

[0075] Combination Figure 2a , Figure 2b As shown, the compressor system provided in this embodiment includes a compressor 200 and an oil separator 210, with the inlet end of the oil separator 210 connected to the discharge side of the compressor 200; it also includes:

[0076] The oil return path includes a throttling connection component 220 and a gas-liquid separator 230 connected in sequence through pipelines; the inlet end of the oil return path is connected to the oil outlet end of the oil separator 210; the oil return hole of the gas-liquid separator 230 is connected to the suction side of the compressor 200 through the outlet end of the oil return path.

[0077] The current detection component 240 is configured to detect the current value of the compressor 200;

[0078] The controller 250 is configured to control the throttling connection component 240 to connect or disconnect the return oil flow path based on the detection result of the current detection component 240.

[0079] Generally, a multi-split air conditioner includes one or more outdoor units and multiple indoor units. The compressor system is located in the outdoor unit. This embodiment uses one compressor system in a multi-split air conditioner as an example to illustrate the solution. In other embodiments, the multi-split air conditioner may use one or more compressor systems as described in this embodiment.

[0080] Here, by feeding back the oil return path to the compressor's suction side through the gas-liquid separator, the compressor oil can return to the compressor through the oil return hole of the gas-liquid separator. This avoids the situation where the compressor oil directly enters the compressor scroll plate, which may be caused by the compressor oil returning directly to the compressor suction side. This prevents the scroll plate from breaking due to the compressor oil not being able to be compressed.

[0081] The compressor system provided in this embodiment detects the compressor's current value using a current detection device to determine the compressor's oil status. This allows control of a throttling and connecting component installed on the oil return path, enabling the throttling or disconnection of the oil return path. When the oil return path is throttled and open, compressor oil returns to the compressor's suction side through the oil return port of the gas-liquid separator, preventing compressor wear caused by oil shortage. When the oil return path is disconnected, unnecessary oil return actions are avoided, preventing system capacity loss caused by connecting the high and low pressure sides.

[0082] Optionally, the return oil flow path further includes a filter 260, disposed between the inlet end of the return oil flow path and the throttling connection component 220, to prevent fluid impurities in the return oil flow path from clogging the throttling connection component 220.

[0083] Optionally, the throttling connection component 220 includes an electronic expansion valve. The electronic expansion valve can adjust its opening degree according to instructions and has a throttling function. Here, when the electronic expansion valve is closed, the return oil flow path is cut off, and the return oil action stops. When the electronic expansion valve is open, the return oil flow path is opened, and the fluid in the flow path is throttled; and the return oil volume can be adjusted by regulating the opening degree of the solenoid valve. In some embodiments, a solenoid valve and a capillary tube arranged in series can also be used as the aforementioned throttling connection component. Then, when the solenoid valve is closed, the return oil flow path is cut off; when the solenoid valve is open, the return oil flow path is opened, and the capillary tube throttles the fluid in the flow path.

[0084] Figure 3a This is a connection diagram of another compressor system provided in an embodiment of this disclosure. Figure 3b This is a schematic diagram of the controller connection for the compressor system.

[0085] Combination Figure 3a , Figure 3b As shown, the compressor system provided in this embodiment includes a compressor 300 and an oil separator 310, with the inlet end of the oil separator 310 connected to the discharge side of the compressor 300; it also includes:

[0086] The oil return path includes a throttling connection component 320 and a gas-liquid separator 330 connected in sequence through pipelines; the inlet end of the oil return path is connected to the oil outlet end of the oil separator 310; the oil return hole of the gas-liquid separator 330 is connected to the suction side of the compressor 300 through the outlet end of the oil return path.

[0087] The current detection component 340 is configured to detect the current value of the compressor 300;

[0088] Temperature detection component 350 is used to detect the first temperature of the fluid in the return oil flow path before passing through the throttling and connecting component 320 and the second temperature after passing through the throttling and connecting component 320.

[0089] The controller 360 is configured to control the throttling connection component 320 to connect or disconnect the return oil flow path based on the detection results of the current detection component 340 and the temperature detection component 350.

[0090] Here, the temperature detection component is used to detect the temperature before and after throttling of the throttling connection component. Since the compressor oil does not undergo significant gas-liquid phase changes, its temperature does not change significantly when passing through the throttling connection component; however, the refrigerant temperature drops significantly after throttling. Therefore, the compressor oil state can be determined by the detection results of the temperature detection component and the current detection component, thereby controlling the throttling connection component located on the oil return path to achieve throttling or interruption of the oil return path.

[0091] Optionally, the temperature detection assembly 350 includes: a pre-throttling temperature sensor 351, disposed between the throttling connection assembly 320 and the compressor 300; and a post-throttling temperature sensor 352, disposed between the throttling connection assembly 320 and the gas-liquid separator 330. The temperature sensors obtain the temperature change of the fluid before and after throttling. Here, the pre-throttling temperature sensor 351 can be a temperature sensor at the top of the compressor, or a temperature sensor disposed between the compressor discharge side and the throttling connection device.

[0092] Optionally, the return oil flow path further includes a filter 370, disposed between the inlet end of the return oil flow path and the throttling connection component 320, to prevent fluid impurities in the return oil flow path from clogging the throttling connection component 320.

[0093] Optionally, the throttling connection component 320 includes an electronic expansion valve. The electronic expansion valve can adjust its opening degree according to instructions and has a throttling function. Here, when the electronic expansion valve is closed, the return oil flow path is cut off, and the return oil action stops. When the electronic expansion valve is open, the return oil flow path is opened, and the fluid in the flow path is throttled; and the return oil volume can be adjusted by regulating the opening degree of the solenoid valve.

[0094] In this way, the throttling connection component can be controlled to open or close the oil return path based on the detection results of the current detection component and the temperature detection component. When the oil return path is throttled and open, the compressor oil can return to the suction side of the compressor through the oil return hole of the gas-liquid separator, avoiding compressor wear caused by oil shortage. When the oil return path is closed, unnecessary oil return actions can be avoided, and system capacity loss caused by the connection between the high and low pressure sides can be avoided.

[0095] Figure 4a A connection diagram of a multi-split air conditioner is shown. Figure 4b A schematic diagram of the controller connection for this multi-split air conditioner is shown.

[0096] like Figure 4a , 4b As shown, a multi-split air conditioner includes a compressor 400, a main flow path, and a return oil flow path. A multi-split air conditioner includes one or more outdoor units (corresponding to one or more outdoor heat exchangers) and multiple indoor units (corresponding to one or more indoor heat exchangers). This embodiment uses the refrigerant circulation pipeline containing one outdoor heat exchanger and one indoor heat exchanger in a multi-split air conditioner as an example to illustrate the solution. Those skilled in the art can use the technical solution provided in this embodiment to connect the indoor and outdoor units of a multi-split air conditioner, thereby forming a complete refrigerant circulation loop for the multi-split air conditioner. In other embodiments, a multi-split air conditioner may include one or more refrigerant circulation pipelines consisting of a compressor, a main flow path, and a return oil flow path as described in this embodiment.

[0097] The main path includes a compressor 400, an oil separator 410, a four-way valve 421, an outdoor heat exchanger 422, a main path throttling device 423, and an indoor heat exchanger 424, which are connected in sequence through the main pipeline.

[0098] The oil return path includes a throttling connection component 430 and a gas-liquid separator 440 connected in sequence through pipelines; the inlet end of the oil return path is connected to the oil outlet end of the oil separator 410; the oil return hole of the gas-liquid separator 440 is connected to the suction side of the compressor 400 through the outlet end of the oil return path.

[0099] Taking the cooling mode as an example, after the refrigerant and compressor oil output from the compressor 400 enter the oil separator 410, the refrigerant is output through the refrigerant outlet of the oil separator 410, enters the outdoor heat exchanger 422 through the four-way valve 421, and then enters the indoor side. It is throttled by the main pipeline throttling device 423 and becomes low-temperature and low-pressure refrigerant. It undergoes evaporation and heat exchange in the indoor heat exchanger 424 and exchanges heat with the indoor air to deliver cool air into the room. After that, the refrigerant enters the gas-liquid separator 440 through the four-way valve 421 and returns to the suction side of the compressor 400.

[0100] After the refrigerant and compressor oil output from the compressor 400 enter the oil separator 410, the compressor oil is output from the oil outlet end of the oil separator 410, passes through the throttling connection component 430 and enters the gas-liquid separator 440, and returns to the suction side of the compressor 400 through the oil return hole of the gas-liquid separator 440.

[0101] Furthermore, the multi-split air conditioner also includes a current detection component 450 and a controller 460. The current detection component 450 is located within the compressor's electrical control box and is configured to detect the current value of the compressor 400, thereby determining whether the compressor is short of oil based on changes in the compressor 400's current. The controller 460 is configured to control the throttling connection component 430 to either open or close the oil return path based on the detection result of the current detection component 450.

[0102] Furthermore, the throttling connection component 430 includes an electronic expansion valve. When the electronic expansion valve is closed, the return oil flow path is cut off, and the return oil action stops. When the electronic expansion valve is open, the return oil flow path is opened, and the fluid in the flow path is throttled; and the amount of return oil can be adjusted by adjusting the opening degree of the solenoid valve.

[0103] Furthermore, the multi-split air conditioner also includes a temperature detection component 470 for detecting a first temperature of the fluid in the return oil flow path before passing through the throttling connection component 430 and a second temperature after passing through the throttling connection component 430; the controller 460 is configured to control the throttling connection component to connect or disconnect the return oil flow path based on the detection results of the current detection component and the detection results of the temperature detection component.

[0104] Specifically, the temperature detection assembly 470 includes a pre-throttling temperature sensor 471 disposed between the throttling connection assembly 430 and the compressor 400, and a post-throttling temperature sensor 472 disposed between the throttling connection assembly 430 and the gas-liquid separator 440.

[0105] Here, the temperature detection component is used to detect the temperature before and after throttling of the throttling connection component. Since the compressor oil does not undergo significant gas-liquid phase changes, its temperature does not change significantly when passing through the throttling connection component; however, the refrigerant temperature drops significantly after throttling. Therefore, the compressor oil state can be determined by the detection results of the temperature detection component and the current detection component, thereby controlling the throttling connection component located on the oil return path to achieve throttling or interruption of the oil return path.

[0106] Furthermore, it also includes a filter 480, which is disposed between the inlet end of the return oil flow path and the throttling connection component 430, in order to prevent fluid impurities in the return oil flow path from clogging the throttling connection component 4300.

[0107] Figure 5 This is a flowchart illustrating a control method for compressor oil return provided in an embodiment of this disclosure, applied to the multi-split air conditioner shown in Figure 4. This method can be executed by the processor of the multi-split air conditioner, or by a cloud server communicating with the multi-split air conditioner; it can also be executed at the control terminal of the multi-split air conditioner. In this embodiment, the processor of the multi-split air conditioner is used as the execution entity to describe the solution.

[0108] Combination Figure 5 As shown, the control method for compressor oil return includes:

[0109] Step S501: With the oil return path connected, obtain the current value of the compressor.

[0110] Here, "oil return path connection" means that the throttling connection component is open, and the pipeline from the oil outlet of the oil separator to the compressor suction side is connected. The current value of the compressor is obtained through a current detection component, which may include a current detection circuit or a detection device such as a multimeter.

[0111] Step S502: Based on the current value range satisfied by the current value, determine the control strategy for the throttling and connecting component so that the return oil flow path remains connected or disconnected.

[0112] Different compressor current values ​​correspond to different oil states. Therefore, by determining the current value range satisfied by the current value, the corresponding compressor oil state is obtained, thereby determining the appropriate throttling connection component control strategy to adjust the connection or disconnection of the oil return path. In this way, when the oil return path is throttled and open, compressor oil can return to the compressor's suction side through the oil return hole of the gas-liquid separator, preventing compressor wear caused by oil shortage. When the oil return path is cut off, unnecessary oil return actions can be avoided, preventing system capacity loss caused by connecting the high and low pressure sides.

[0113] Figure 6 This is a flowchart illustrating a control method for compressor oil return provided in an embodiment of this disclosure, applied to the multi-split air conditioner shown in Figure 4. In this embodiment, the processor of the multi-split air conditioner is used as the execution subject to describe the solution.

[0114] Combination Figure 6 As shown, the control method for compressor oil return includes:

[0115] Step S601: With the oil return path connected, obtain the current value of the compressor.

[0116] Step S602: If the current value is greater than the first current threshold, control the throttling connection component to cut off the return oil flow path.

[0117] Step S603: If the current current value is less than or equal to the first current threshold, obtain the first temperature of the fluid in the return oil flow path before passing through the throttling and connecting component and the second temperature after passing through the throttling and connecting component.

[0118] Step S604: Determine the control strategy for the throttling connection component based on the current temperature difference between the first temperature and the second temperature.

[0119] Here, the first current threshold represents the compressor current value when the compressor is in a full oil condition. If the current value is greater than the first current threshold, it indicates that the compressor's oil return is normal, and the oil return path can be cut off. After some compressor oil is consumed / flows out, the oil return path can be restored. If the current value is less than or equal to the first current threshold, it indicates that the compressor is not in a full oil condition. It is necessary to determine whether there is oil to return based on the temperature change before and after throttling in the oil return line, thereby avoiding unnecessary oil return actions.

[0120] Optionally, obtaining the first current threshold includes: acquiring the correspondence between the compressor frequency, the oil state inside the compressor, and the compressor current; acquiring the current frequency of the compressor, and determining the compressor current corresponding to the current frequency when the compressor is in a full oil state as the first preset current; determining the first current threshold based on the first preset current; and the first preset current being greater than the first current threshold.

[0121] Here, the current corresponding to different frequency values ​​of the compressor under the same oil condition can be obtained experimentally, thus obtaining the above-mentioned correspondence. For example, the current corresponding to different frequency values ​​of the compressor under full oil condition can be obtained, thus obtaining the correspondence between compressor frequency, full oil condition, and compressor current. When obtaining the current compressor frequency, the compressor current value under full oil condition corresponding to the current compressor frequency can be obtained by querying the database, which is used as the first preset current, and the first current threshold mentioned above can be determined based on the first preset current.

[0122] In this embodiment, the first current threshold is obtained in the following manner:

[0123] I n1 =k1×I m1

[0124] Among them, I n1 I is the first current threshold. m1 Let k1 be the first preset current and k1 be the first weighting value, where k1 < 1.

[0125] In some embodiments, the value of k1 is determined based on the current frequency of the compressor, and the compressor frequency is positively correlated with the value of k1. Further, the value of k1 ranges from 0.85 to 0.99, for example, 0.85, 0.88, 0.90, 0.93, 0.95, 0.99, etc. In this embodiment, k1 = 0.9.

[0126] Optionally, a control strategy for the throttling and connecting component is determined based on the current temperature difference between the first temperature and the second temperature, including:

[0127] If the current temperature difference is greater than the first temperature difference, the control strategy used for the throttling and connecting components includes:

[0128] Close the throttling connection component at the current opening to cut off the return oil flow path;

[0129] If the current temperature difference is less than or equal to the second temperature difference, the control strategy used for the throttling and connecting component includes:

[0130] Increase the opening of the throttling connection component to keep the return oil flow path connected and increase the return oil volume;

[0131] The first temperature difference is greater than the second temperature difference.

[0132] Here, the difference between the first and second temperatures determines whether the fluid in the pipeline is predominantly refrigerant or compressor oil. Since compressor oil does not undergo significant gas-liquid phase changes, when the fluid passing through the return oil path is entirely or mostly compressor oil, the fluid temperature before and after throttling will not change significantly; however, the temperature of refrigerant will decrease significantly after throttling. Therefore, the fluid composition in the return oil path can be determined using a temperature detection component, allowing for appropriate control strategies.

[0133] The first temperature difference value indicates a significant temperature change in the fluid within the pipeline before and after throttling. When the current temperature difference value exceeds the first temperature difference value, it indicates that all or most of the fluid in the pipeline is refrigerant, and there is no oil to return from the oil separator. In this case, if the throttling connection component continues to be opened, allowing the oil return path to be open, the compressor's discharge and suction are depressurized, which is not conducive to the establishment of the overall system pressure differential. The oil remaining in the system pipeline cannot return under the action of the high-flow-rate refrigerant, which is detrimental to system oil return. Therefore, it is necessary to close the throttling connection component to cut off the oil return path.

[0134] The second temperature difference is used to indicate the situation where the temperature change of the fluid in the pipeline is small before and after throttling. When the current temperature difference is less than or equal to the second temperature difference, it indicates that all or most of the fluid in the pipeline is compressor oil, and a large amount of compressor oil in the oil separator has not been returned. In this case, the opening of the throttling device can be increased to increase the amount of oil returned and accelerate the oil return rate.

[0135] Optionally, the first temperature difference is greater than or equal to 5℃, and its range can be set to [5℃, 7℃], for example, 5℃, 6℃, 7℃; in this embodiment, the first temperature difference is set to 5℃. The second temperature difference is less than or equal to 2℃, and its range can be set to (0℃, 2℃], for example, 1.2℃, 1.5℃, 1.7℃, 2℃; in this embodiment, the second temperature difference is set to 2℃.

[0136] Furthermore, increasing the opening degree of the throttling connection component includes:

[0137] Determine the opening adjustment value for increasing the opening degree of the throttling connection component based on the current current value;

[0138] The sum of the current opening degree and the opening degree adjustment value is determined as the target opening degree, and the throttling connection component is controlled to increase to the target opening degree adjustment at a set rate.

[0139] Here, increasing the opening degree of the throttling connection component is to increase the oil return volume, and the current value can indicate the oil condition of the compressor. Therefore, the opening degree of the throttling connection component is determined by the current value, thereby adjusting the oil return rate of the oil return path according to the oil condition of the compressor.

[0140] The correspondence between compressor current value and opening adjustment value can be obtained through experimentation. After obtaining the current current value, the opening adjustment value corresponding to the current current value can be obtained by querying the database, and the target opening value can be determined based on the opening adjustment value.

[0141] Furthermore, determining the opening adjustment value for increasing the opening degree of the throttling connection component based on the current current value may include:

[0142] Obtain the current difference between the current value and the first preset current;

[0143] The opening adjustment value for increasing the opening degree of the throttling connection component is determined based on the absolute value of the current difference between the current value and the first preset current.

[0144] Here, the absolute value of the current difference and the absolute value of the difference between the first preset current are negatively correlated with the magnitude of the opening adjustment value.

[0145] The correspondence between the compressor current difference and the opening adjustment value can be obtained through experimentation. After obtaining the current value, the current difference between the current value and the first preset current under full oil conditions can be obtained by querying the database. Based on the above correspondence, the opening adjustment value corresponding to the current current difference can be obtained, and then the target opening can be determined based on the opening adjustment value.

[0146] Alternatively, the correspondence between the compressor current value and the opening adjustment value can be in the form of a formula. After obtaining the current compressor current value, the difference between the current current value and the first preset current under full oil condition is used as the independent variable of the formula to calculate the opening adjustment value corresponding to the current current value.

[0147] Further, based on the current current value, a setting adjustment value for increasing the opening degree of the throttling component is determined, including:

[0148] If the current value is greater than the second current threshold, the opening adjustment value is determined as the first opening adjustment value;

[0149] If the current value is less than or equal to the second current threshold, then the opening adjustment value is determined as the second opening adjustment value;

[0150] Among them, the second current threshold is less than the first current threshold; the first opening adjustment value is greater than the second opening adjustment value.

[0151] Here, the second current threshold is used to represent the current threshold when the compressor is not full of oil. This enables the opening adjustment value to be determined based on the oil condition of the compressor, thereby adjusting the oil return rate of the oil return path.

[0152] Obtaining the second current threshold includes:

[0153] Obtain the correspondence between compressor frequency, compressor oil status, and compressor current;

[0154] Obtain the current frequency of the compressor, and determine the compressor current corresponding to the condition where the compressor is not full of oil at the current frequency as the second preset current;

[0155] The second current threshold is determined based on the second preset current; the second preset current is greater than the second current threshold.

[0156] The non-full oil state includes both the oil shortage state and the oil supply state; the second preset current is greater than the first preset current.

[0157] Here, the current corresponding to different frequency values ​​of the compressor under the same oil condition can be obtained experimentally, thus obtaining the aforementioned correspondence. For example, the current corresponding to different frequency values ​​of the compressor under a non-full oil condition can be obtained, thus establishing the correspondence between compressor frequency, non-full oil condition, and compressor current. When obtaining the current compressor frequency, the compressor current value under a non-full oil condition corresponding to the current compressor frequency can be obtained by querying a database, serving as the second preset current. The second current threshold mentioned above can then be determined based on this second preset current. Specifically, the compressor current value under an oil-filled condition corresponding to the current compressor frequency can be used as the aforementioned second preset current.

[0158] In this embodiment, the second current threshold is obtained in the following manner:

[0159] I n2 =k2×I m2

[0160] Among them, I n2 For the second current threshold, I m2 The second preset current is given, and k2 is the weighting value, where k2 < 1.

[0161] In some embodiments, the value of k2 is determined based on the current frequency of the compressor, and the compressor frequency is positively correlated with the value of k2. Further, the value of k2 ranges from 0.85 to 0.99, for example, 0.85, 0.88, 0.90, 0.93, 0.95, 0.99, etc. In this embodiment, k2 = 0.9.

[0162] Thus, the compressor oil return control method for multi-split air conditioners provided in this embodiment of the present disclosure determines the compressor's oil state by detecting the compressor's current value, and controls the throttling and connecting component installed on the oil return path to achieve throttling and opening or closing of the oil return path. When the compressor's current value indicates that the compressor's oil state is not full, the connection or closure of the oil return path is determined by the temperature difference of the fluid before and after throttling in the oil return path. In the throttling and opening state of the oil return path, compressor oil can return to the compressor's suction side through the oil return hole of the gas-liquid separator, avoiding compressor wear caused by insufficient oil. In the case of throttling the oil return path, unnecessary oil return actions can be avoided, preventing system capacity loss caused by connecting the high and low pressure sides.

[0163] Figure 7 This is a flowchart illustrating a control method for compressor oil return provided in an embodiment of this disclosure, applied to the multi-split air conditioner shown in Figure 4. In this embodiment, the processor of the multi-split air conditioner is used as the execution subject to describe the solution.

[0164] Combination Figure 7 As shown, the control method for compressor oil return includes:

[0165] Step S701: Obtain the compressor's operating frequency when the multi-split air conditioner is operating stably.

[0166] Step S702: Determine the interval duration for controlling the connection of the return oil flow path based on the compressor's operating frequency; the compressor's operating frequency is negatively correlated with the interval duration.

[0167] Step S703: With the oil return path connected, obtain the current value of the compressor.

[0168] Step S704: If the current current value is greater than the first current threshold corresponding to the full oil state, control the throttling connection component to cut off the return oil flow path. After the return oil flow path is cut off, if the interval time has not been reached and the current current value is within the set current range, control the return oil flow path to open.

[0169] Step S705: If the current current value is less than or equal to the first current threshold, obtain the temperature difference ΔT between the first temperature T1 of the fluid in the return oil flow path before passing through the throttling and connecting component and the second temperature T2 after passing through the throttling and connecting component.

[0170] Step S706, if ΔT is greater than the first temperature difference T S1 If the current opening is closed, the throttling connection component will be shut off, thus cutting off the return oil flow path.

[0171] Step S707: If ΔT is less than or equal to the first temperature difference TS1 and greater than the second temperature difference TS2, then control the throttling connection component to maintain the current opening within the interval time to make the return oil flow path connected.

[0172] In step S708, if ΔT is less than the second temperature difference TS2, the opening of the throttling connection component is increased within the interval to keep the return oil flow path connected and increase the return oil volume.

[0173] Among them, obtaining information on the stable operating status of multi-split air conditioners includes:

[0174] The high pressure at the compressor's discharge port and the low pressure at the compressor's suction port are detected, and the ratio of the high pressure to the low pressure is determined as the compression ratio.

[0175] If the compression ratio is within the preset range, the multi-split air conditioner is considered to be operating stably.

[0176] The set current range is used to indicate that the compressor is in an oil-filled state that is neither full nor short of oil.

[0177] Generally, compressor wear increases and current rises when the compressor is short of oil. Therefore, corresponding to the current threshold I1 representing a full oil condition, the current threshold in the oil-filled condition is denoted as I2, and the current threshold in the short-oil condition is denoted as I3, where I1 < I2 < I3. The set current range is represented as [0.9I2, 1.1I2], indicating that the deviation between the current value and the current threshold I2 in the oil-filled condition is within 10%.

[0178] Thus, the compressor oil return control method for multi-split air conditioners provided in this embodiment of the present disclosure determines the compressor's oil state by detecting the compressor's current value, and controls the throttling and connecting component installed on the oil return path to achieve throttling and opening or closing of the oil return path. When the compressor's current value indicates that the compressor's oil state is not full, the connection or closure of the oil return path is determined by the temperature difference of the fluid before and after throttling in the oil return path. In the throttling and opening state of the oil return path, compressor oil can return to the compressor's suction side through the oil return hole of the gas-liquid separator, avoiding compressor wear caused by insufficient oil. In the case of throttling the oil return path, unnecessary oil return actions can be avoided, preventing system capacity loss caused by connecting the high and low pressure sides.

[0179] Figure 8This is a schematic diagram of a control device for compressor oil return provided in an embodiment of this application, applied to the multi-split air conditioner shown in Figure 4. Combined with... Figure 8 As shown, the control device for compressor oil return includes:

[0180] The device includes a processor 80 and a memory 81. Optionally, it may also include a communication interface 82 and a bus 83. The processor 80, communication interface 82, and memory 81 can communicate with each other via the bus 83. The communication interface 82 can be used for information transmission. The processor 80 can call logical instructions in the memory 81 to execute the compressor oil return control method described in the above embodiment.

[0181] Furthermore, the logic instructions in the aforementioned memory 81 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium.

[0182] The memory 81, as a computer-readable storage medium, can be used to store software programs and computer-executable programs, such as program instructions / modules corresponding to the methods in the embodiments of this disclosure. The processor 80 executes functional applications and data processing by running the program instructions / modules stored in the memory 81, thereby implementing the control method for compressor oil return in the above embodiments.

[0183] The memory 81 may include a program storage area and a data storage area. The program storage area may store the operating system and application programs required for at least one function; the data storage area may store data created based on the use of the terminal device. Furthermore, the memory 81 may include high-speed random access memory and may also include non-volatile memory.

[0184] This disclosure provides a multi-split air conditioner that includes the above-described control method for compressor oil return.

[0185] This disclosure provides a computer-readable storage medium storing computer-executable instructions configured to execute the above-described control method for compressor oil return.

[0186] This disclosure provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions that, when executed by a computer, cause the computer to perform the above-described control method for compressor oil return.

[0187] The aforementioned computer-readable storage medium may be a transient computer-readable storage medium or a non-transitory computer-readable storage medium.

[0188] The technical solutions of this disclosure can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes one or more instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in this disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, and other media capable of storing program code; it can also be a transient storage medium.

[0189] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0190] Those skilled in the art will 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, or a combination of computer software and electronic hardware. 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 the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0191] The methods and products (including but not limited to devices and equipment) disclosed in the embodiments herein can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of units may be merely a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the shown or discussed units may be through some interfaces, and the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the units may be selected to implement this embodiment according to actual needs. Furthermore, the functional units in the embodiments of this disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0192] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A compressor system comprising a compressor and an oil separator, wherein the inlet end of the oil separator is connected to the discharge side of the compressor; characterized in that, Also includes: The oil return path includes a throttling and connecting component and a gas-liquid separator connected in sequence by pipelines; the inlet end of the oil return path is connected to the oil outlet end of the oil separator; the oil return hole of the gas-liquid separator is connected to the suction side of the compressor through the outlet end of the oil return path; A current detection component is configured to detect the current value of the compressor; A temperature detection component is used to detect the first temperature of the fluid in the return oil flow path before passing through the throttling and connecting component and the second temperature after passing through the throttling and connecting component; The controller is configured as follows: Obtain the current current value of the compressor; If the current value is greater than the first current threshold, the throttling connection component is controlled to cut off the return oil flow path; If the current current value is less than or equal to the first current threshold, then the first temperature and the second temperature are obtained, and a control strategy for the throttling connection component is determined based on the current temperature difference between the first temperature and the second temperature. If the current temperature difference is less than or equal to the second temperature difference, then an opening adjustment value for increasing the opening of the throttling connection component is determined based on the current current value. The sum of the current opening and the opening adjustment value is determined as the target opening. The throttling connection component is then controlled to increase to the target opening at a set rate, so that the return oil flow path remains connected and the return oil volume is increased.

2. The compressor system according to claim 1, characterized in that, The temperature detection component includes: A temperature sensor before throttling is disposed between the throttling connection assembly and the compressor; A temperature sensor after throttling is installed between the throttling connection component and the gas-liquid separator.

3. The compressor system according to claim 1, characterized in that, The return oil flow path also includes: A filter is disposed between the inlet end of the return oil flow path and the throttling connection component.

4. The compressor system according to any one of claims 1 to 3, characterized in that, The throttling connection component includes an electronic expansion valve.

5. A multi-split air conditioner, characterized in that, include: The compressor system as described in any one of claims 1 to 4.

6. A control method for compressor oil return, applied in the multi-split air conditioner of claim 5, characterized in that, include: With the return oil flow path connected, obtain the current value of the compressor; If the current value is greater than the first current threshold, the throttling connection component is controlled to cut off the return oil flow path; If the current value is less than or equal to the first current threshold, then obtain the first temperature of the fluid in the return oil flow path before passing through the throttling connection component and the second temperature after passing through the throttling connection component; Based on the current temperature difference between the first temperature and the second temperature, a control strategy for the throttling connection component is determined; If the current temperature difference is less than or equal to the second temperature difference, then the opening adjustment value for increasing the opening of the throttling connection component is determined based on the current current value. The sum of the current opening degree and the opening degree adjustment value is determined as the target opening degree, and the throttling connection component is controlled to increase to the target opening degree adjustment at a set rate, so that the return oil flow path remains connected and the return oil volume is increased.

7. The control method according to claim 6, characterized in that, Obtaining the first current threshold includes: Obtain the correspondence between compressor frequency, compressor oil status, and compressor current; Obtain the current frequency of the compressor, and determine the compressor current corresponding to the current frequency when the compressor is full of oil as the first preset current; The first current threshold is determined based on the first preset current; the first preset current is greater than the first current threshold.

8. The control method according to claim 6, characterized in that, The step of determining the control strategy for the throttling and connecting component based on the current temperature difference between the first temperature and the second temperature further includes: If the current temperature difference is greater than the first temperature difference, the control strategy for the throttling and connecting component includes: Close the throttling connection component at the current opening degree to cut off the return oil flow path; Wherein, the first temperature difference is greater than the second temperature difference.

9. The control method according to claim 7, characterized in that, The step of determining the opening adjustment value for increasing the opening degree of the throttling connection component based on the current current value includes: If the current value is greater than the second current threshold, then the opening adjustment value is determined as the first opening adjustment value; If the current current value is less than or equal to the second current threshold, then the opening adjustment value is determined as the second opening adjustment value; Wherein, the second current threshold is less than the first current threshold; and the first opening adjustment value is greater than the second opening adjustment value.

10. The control method according to claim 9, characterized in that, Obtaining the second current threshold includes: Obtain the correspondence between compressor frequency, compressor oil status, and compressor current; Obtain the current frequency of the compressor, and determine the compressor current corresponding to the non-full oil state of the compressor at the current frequency as the second preset current; The second current threshold is determined based on the second preset current; the second preset current is greater than the second current threshold. The non-full oil state includes both the oil shortage state and the oil supply state; the second preset current is greater than the first preset current.

11. The control method according to any one of claims 6 to 10, characterized in that, Also includes: Based on the operating frequency of the compressor, determine the interval duration for controlling the connection of the oil return path; The operating frequency of the compressor is negatively correlated with the interval duration.

12. A control device for compressor oil return, applied in the multi-split air conditioner of claim 5, comprising a processor and a memory storing program instructions, characterized in that, The processor is configured to execute, when running the program instructions, the control method for compressor oil return as described in any one of claims 6 to 11.

Images