Air conditioning system

Abstract

The invention provides an air conditioning system. The air conditioning system comprises an outdoor module and a processing device. The outdoor module is provided with a compressor, a switching valve, an oil separator and a gas-liquid separator; the processing device comprises an acquisition part, a calculation part and a presumption part; the acquisition part is configured to correspondingly acquire operation parameters of the suction end and the discharge end of the compressor; a calculation section configured to calculate a difference between the suction end operation parameter and the discharge end operation parameter; the presumption part is configured to presume corresponding adjustment operation parameters according to normal operation parameters of a plurality of execution components driven by electric power in the outdoor module on the basis of the difference between the operation parameters of the suction end and the discharge end and a reference balance pressure presumption condition; wherein the reference equilibrium pressure presumption condition is used for judging whether the pressure difference among the plurality of gas-liquid separators is in an unbalanced state or not; in addition, when an execution component in the outdoor module operates according to the adjusting operation parameters, the pressure difference between the multiple gas-liquid separators is reduced. The stability of the air conditioning system can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of air conditioning equipment, in particular to an air conditioning system. BACKGROUND

[0002] More and more models of multi-connected air conditioning systems use double-compressor configuration. Each compressor is correspondingly provided with a gas-liquid separator. The whole system can be regarded as two sets of circulation systems used in parallel. Since the operating parameters of the two sets of systems cannot be completely consistent, especially the natural pressure difference exists in the two gas-liquid separators, which will cause the difference in the oil-liquid mixed liquid level height in the two gas-liquid separators. The oil concentration in one of the gas-liquid separators is getting higher and higher, and the other is getting lower and lower, causing the oil shortage damage of the compressor.

[0003] The prior art provides a way to solve this problem, such as the technical solution disclosed in Chinese patent application (CN116067044A): "A compressor assembly, comprising a first compressor and a second compressor, the first compressor having a first exhaust port and a first return gas port, the second compressor having a second exhaust port and a second return gas port; a first oil separator and a second oil separator, the first oil separator having a first oil outlet and a first oil inlet communicating with the first exhaust port, the second oil separator having a second oil outlet and a second oil inlet communicating with the second exhaust port; a first gas-liquid separator and a second gas-liquid separator, the first gas-liquid separator having a first separation cavity and a first gas inlet, a first oil return hole and a first gas outlet communicating with the first separation cavity, the second gas-liquid separator having a second separation cavity and a second gas inlet, a second oil return hole and a second gas outlet communicating with the second separation cavity, the first oil outlet and the first gas inlet are in communication, the second oil outlet and the second gas inlet are in communication, each of the first gas outlet and the first oil return hole is in communication with the first return gas port, each of the second gas outlet and the second oil return hole is in communication with the second return gas port; and, a liquid balance pipe and a gas balance pipe, the gas balance pipe is located above the liquid balance pipe, one end of the liquid balance pipe and each of the other end of the gas balance pipe are in communication with the first separation cavity, the other end of the liquid balance pipe and each of the other end of the gas balance pipe are in communication with the second separation cavity."

[0004] The prior art is to balance the liquid level in the two gas-liquid separators through the liquid balance pipe and the gas balance pipe, but the liquid refrigerant distributed into the two gas-liquid separators cannot be completely uniform, the system pipeline layout, direction and length are not completely consistent, and the suction capacity of the two compressors cannot be completely consistent, which will cause the pressure difference between the two gas-liquid separators. When the liquid balance pipe reaches the balance state, the liquid level height of the two gas-liquid separators will be different. SUMMARY

[0005] The application is directed to the problem that pressure difference causes the liquid level difference between two gas-liquid separators when the liquid balance pipe reaches the equilibrium state, and discloses an air conditioning system.

[0006] The air conditioning system comprises an outdoor module, an indoor module and a processing device; the outdoor module comprises a plurality of compressors, a switching valve, a plurality of oil separators and a plurality of gas-liquid separators; the plurality of oil separators are respectively arranged at the discharge end of the compressors, the plurality of gas-liquid separators are respectively arranged at the suction end of the compressors, and the liquid balance pipes are arranged between the gas-liquid separators.

[0007] In one or more embodiments of the application, the processing device comprises a collection unit, a calculation unit and an estimation unit; the collection unit is configured to collect the operating parameters of the suction end and the discharge end of the plurality of compressors; the calculation unit is configured to calculate the difference between the operating parameters of the suction end and the difference between the operating parameters of the discharge end; and the estimation unit is configured to estimate the corresponding adjustment operating parameters according to the conventional operating parameters of the plurality of electrically driven execution components of the outdoor module based on the difference between the operating parameters of the suction end, the difference between the operating parameters of the discharge end and the reference equilibrium pressure estimation condition.

[0008] In one or more embodiments of the application, the reference equilibrium pressure estimation condition is used to determine whether the pressure difference between the plurality of gas-liquid separators is in a non-equilibrium state; and when the execution components in the outdoor module operate according to the adjustment operating parameters, the pressure difference between the plurality of gas-liquid separators is reduced.

[0009] In one or more embodiments of the application, the outdoor module comprises a plurality of adjustment branches, and each adjustment branch is arranged between a corresponding oil separator and a gas-liquid separator; each adjustment branch is provided with an execution component; when the execution component operates according to the adjustment operating parameters, the execution component reduces the pressure difference between the plurality of gas-liquid separators by changing the refrigerant flow in at least one adjustment branch.

[0010] In one or more embodiments of the application, the execution component is an electronic expansion valve, and the adjustment operating parameter is the opening degree of the electronic expansion valve; when the adjustment operating parameter is estimated, the following steps are included: obtaining the difference between the operating parameters of the suction end and the difference between the operating parameters of the discharge end; based on the difference between the operating parameters of the suction end and the difference between the operating parameters of the discharge end, reducing the opening degree of the electronic expansion valve corresponding to the gas-liquid separator with higher pressure and increasing the opening degree of the electronic expansion valve corresponding to the gas-liquid separator with lower pressure.

[0011] In one or more embodiments of the present application, based on the difference between the suction end operating parameters and the difference between the discharge end operating parameters, the opening degree of the electronic expansion valve corresponding to the one with higher pressure among the plurality of gas-liquid separators is reduced, and the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators is increased, including: reducing the opening degree of the electronic expansion valve corresponding to the one with higher pressure among the plurality of gas-liquid separators to the lower limit threshold of the opening degree; obtaining the current proportional relationship between the difference between the suction end operating parameters and the difference between the discharge end operating parameters; determining the fitting adjustment amplitude corresponding to the current proportional relationship according to the function relationship established based on the proportional relationship and the opening degree adjustment amplitude; gradually increasing the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators by taking the product of the previous electronic expansion valve opening degree and the fitting adjustment amplitude as the actual opening degree for a plurality of consecutive times, until the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators reaches the maximum opening degree, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; wherein the initial opening degree of the electronic expansion valve is the minimum flow opening degree.

[0012] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening degree adjustment amplitude is obtained by: under simulated conditions, collecting the difference between the suction end operating parameters and the difference between the discharge end operating parameters; calculating the proportional relationship corresponding to the difference between the suction end operating parameters and the difference between the discharge end operating parameters; reducing the opening degree of the electronic expansion valve corresponding to the one with higher pressure among the plurality of gas-liquid separators to the lower limit threshold; randomly generating a set of adjustment amplitudes and adjustment frequencies in a preset data pool; dividing the set time length into a plurality of consecutive periods based on the adjustment frequency, and gradually increasing the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators by taking the product of the electronic expansion valve opening degree of the previous period and the random adjustment amplitude as the actual opening degree; at the end of the set time length, it is determined whether the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; if it is no longer in a non-equilibrium state, record the corresponding ratio and adjustment amplitude as valid data points; repeat the above process to fit the function relationship between the proportional relationship and the opening degree adjustment amplitude.

[0013] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening degree adjustment amplitude is a polynomial fitting function.

[0014] In one or more embodiments of the present application, the execution component is an electromagnetic valve, and the adjusted operation parameter is the on-off of the electromagnetic valve. When the execution component is presumed to adjust the operation parameter, the following steps are included: obtaining the difference between the suction end operation parameters and the difference between the discharge end operation parameters; based on the difference between the suction end operation parameters and the difference between the discharge end operation parameters, closing the electromagnetic valve corresponding to the one with higher pressure among the plurality of gas-liquid separators according to the set intervention period, and opening the electromagnetic valve corresponding to the one with lower pressure among the plurality of gas-liquid separators.

[0015] In one or more embodiments of the present application, the execution component is a plurality of compressors; when the execution component operates according to the adjusted operation parameter, the execution component changes the current operating frequency of the compressors so that the pressure difference between the plurality of gas-liquid separators is reduced.

[0016] In one or more embodiments of the present application, the difference between the suction end operation parameters is the difference in the suction temperature of the compressors; and the difference between the discharge end operation parameters is the difference in the discharge temperature of the compressors.

[0017] In one or more embodiments of the present application, the reference balance pressure presumption condition is that the difference in the suction temperature of the compressors is higher than a set temperature threshold, and the difference in the discharge temperature of the compressors is higher than a set temperature threshold.

[0018] The present application realizes accurate collection and calculation through the cooperation of the collection unit, the calculation unit and the presumption unit, and presumes the best adjusted operation parameter to automatically reduce the pressure difference between the gas-liquid separators in real time by adjusting the execution component, thereby improving the stability and operation efficiency of the air conditioning system and reducing mechanical wear and energy loss.

[0019] Other features and advantages of the present application will become more apparent from the following specific embodiments of the present application combined with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative labor.

[0021] Figure 1 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0022] Figure 2 is a structural schematic diagram of an air conditioning system in a refrigeration mode provided by one or more embodiments of the present application;

[0023] Figure 3 is a structural schematic diagram of an air conditioning system in a heating mode according to one or more embodiments of the present application;

[0024] Figure 4 is a structural schematic diagram of an air conditioning system according to one or more embodiments of the present application;

[0025] Figure 5 is a structural schematic diagram of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0026] Figure 6 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0027] Figure 7 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0028] Figure 8 is an example of a polynomial fit function;

[0029] Figure 9 is a structural schematic diagram of an air conditioning system according to one or more embodiments of the present application;

[0030] Figure 10 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0031] Figure 11 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0032] Figure 12 is a structural schematic diagram of an air conditioning system according to one or more embodiments of the present application;

[0033] Figure 13 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0034] Figure 14 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0035] Figure 15 is a structural schematic diagram of an air conditioning system according to one or more embodiments of the present application;

[0036] Figure 16 is an example of a polynomial fit function;

[0037] Figure 17 is a flowchart of a processing device in an air conditioning system according to one or more embodiments of the present application;

[0038] Figure 18 is a structural schematic diagram of an air conditioning system provided by one or more embodiments of the present application;

[0039] Figure 19 is a flow chart of a processing device in an air conditioning system provided by one or more embodiments of the present application;

[0040] In the figure: 10, outdoor module; 20, indoor module; 30, processing device; 101, first compressor; 102, second compressor; 103, first high-pressure switch; 104, second high-pressure switch; 105, first oil separator; 106, second oil separator; 107, first oil return branch; 108, second oil return branch; 109, filter; 110, filter; 111, first oil return capillary; 112, second oil return capillary; 113, exhaust pressure sensor; 114, switching valve; 115, outdoor heat exchanger; 116, outdoor throttling element; 117, liquid pipe stop valve; 118, liquid pipe; 119, indoor throttling element; 120, indoor heat exchanger; 121, indoor throttling element; 122, indoor heat exchanger; 123, indoor throttling element; 124, indoor heat exchanger; 125, gas pipe; 126, gas pipe stop valve; 127, distribution pipeline; 128, low-pressure side pressure sensor; 129, first drainage pipe; 130, second drainage pipe; 131, distributor; 132, first gas-liquid separator; 133, second gas-liquid separator; 134, first U-shaped pipe; 135, second U-shaped pipe; 136, gas equalization pipe; 137, liquid equalization pipe; 138, first exhaust temperature sensor; 139, second exhaust temperature sensor; 140, first suction temperature sensor; 141, second suction temperature sensor; 142, converging pipeline; 143, first regulating branch; 144, first electronic expansion valve; 145, filter; 146, second regulating branch; 147, second electronic expansion valve; 148, filter; 149, first outlet pipeline; 150, second outlet pipeline; 151, regulating branch; 152, filter; 153, electromagnetic valve; 154, regulating capillary; 155, first regulating branch; 156, filter; 157, first electromagnetic valve; 158, first regulating capillary; 159, second regulating branch; 160, filter; 161, second electromagnetic valve; 162, second regulating capillary; 163, outdoor fan;

[0041] 301, processor; 302, non-volatile memory; 303, volatile memory; 304, display device; 305, operation device; 306, communication interface; 307, drive device; 308, bus; 309, storage medium; 310, storage medium. DETAILED DESCRIPTION

[0042] With reference to the drawings and the descriptions of embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0043] In the description of the present application, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0044] The terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "a plurality of" means two or more.

[0045] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through an intermediate medium, or internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] In the present application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above" and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "under", "below" and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0047] The following disclosure provides many different embodiments, or examples, for implementing different structures of the application. For the purpose of simplicity, the elements and acts of the various examples in the following detailed description are combined where appropriate for the purpose of providing a concise, easy to follow description. These combined elements and acts can not explicitly be set forth in a single clause. For the purpose of clarity, the description will be divided into multiple numbered clauses. In the description below, for simplicity of the inclusion of a large number of specific details and explicit references to save the purpose of providing a clear understanding of the disclosed embodiments, the description will not necessarily show structural details of the specific implementation and will outline the functional elements of the different embodiments. Therefore, certain

[0048] In the following, one or more embodiments of the present application will be described in detail with reference to the accompanying drawings.

[0049] The present application relates to an air conditioning system, and in particular to a multi-split air conditioning system. The multi-split air conditioning system is an air conditioning system that can independently cool and heat multiple rooms or areas, and the temperature of each room or area can be independently or combined controlled. The multi-split air conditioning system is particularly suitable for buildings, such as office buildings, schools, hotels and large residential buildings, which require independent temperature control and include multiple rooms or areas.

[0050] Figure 1 The structural schematic diagram of the air conditioning system provided by one or more specific embodiments of the present application is shown.

[0051] A refrigeration cycle is integrated in the multi-split air conditioning system. The refrigeration cycle uses a compressor, a condenser, a throttling device and an evaporator. The refrigeration cycle includes a series of processes, involving compression, condensation, expansion and evaporation, to refrigerate or heat the indoor space.

[0052] From the principle point of view, the low-temperature and low-pressure refrigerant enters the compressor, which compresses the refrigerant gas into a high-temperature and high-pressure state and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser, which condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0053] The throttling device expands the high-temperature and high-pressure liquid-phase refrigerant formed in the condenser into low-pressure liquid-phase refrigerant. The evaporator evaporates the refrigerant expanded in the throttling device and returns the refrigerant in a low-temperature and low-pressure state to the compressor. The evaporator can achieve the refrigeration effect by exchanging heat with the material to be cooled by using the latent heat of evaporation of the refrigerant. Throughout the cycle, the air conditioning system can adjust the temperature of the indoor space.

[0054] As Figure 1 As shown in one or more embodiments of the present application, the air conditioning system includes an outdoor module 10 and an indoor module 20 connected to each other.

[0055] The outdoor module 10 and the indoor module 20 are connected by a liquid pipe 118 and a gas pipe 125. The liquid pipe 118 and the gas pipe 125 are used for the flow of refrigerant, so that the refrigerant can form a refrigerant circuit and circulate therein.

[0056] In one or more embodiments of the present application, the liquid pipe 118 is provided with a liquid pipe stop valve 117.

[0057] In one or more embodiments of the present application, the gas pipe 125 is provided with a gas pipe stop valve 126.

[0058] The outdoor module 10 is described below, as shown in Figures 1 to 3

[0059] In one or more embodiments of the present application, the outdoor module 10 is part of a refrigeration cycle including a compressor and an outdoor heat exchanger 115. The outdoor module 10 can perform heating operation or refrigeration operation on the outdoor side to provide energy for increasing the indoor temperature or energy for reducing the indoor temperature to the indoor module 20. The outdoor heat exchanger 115 is correspondingly provided with an outdoor throttling element 116.

[0060] In one or more embodiments of the present application, the outdoor module 10 includes a plurality of compressors, for example, a first compressor 101 and a second compressor 102 as shown in Figure 1

[0061] The discharge end of the first compressor 101 is provided with a first high-pressure switch 103, and the discharge end of the second compressor 102 is provided with a second high-pressure switch 104. The first high-pressure switch 103 and the second high-pressure switch 104 are used to monitor the pressure in the system. When the pressure in the air conditioning system exceeds the set safety threshold, the first high-pressure switch 103 and / or the second high-pressure switch 104 will automatically cut off the power supply to stop the operation of the first compressor 101 and / or the second compressor 102, in order to protect the equipment and devices in the air conditioning system from damage caused by high pressure. The safety threshold of the first high-pressure switch 103 and / or the second high-pressure switch 104 can be set according to the design parameters and working conditions of the air conditioning system. Once the pressure in the system is reduced to a safe level, the first high-pressure switch 103 and / or the second high-pressure switch 104 will restore the power supply to restart the first compressor 101 and / or the second compressor 102.

[0062] In one or more embodiments of the present application, the discharge end of the first compressor 101 is provided with a first discharge temperature sensor 138, and the discharge end of the second compressor 102 is provided with a second discharge temperature sensor 139.

[0063] ​​In one or more embodiments of the present application, the suction end of the first compressor 101 is provided with a first suction temperature sensor 140, and the suction end of the second compressor 102 is provided with a second suction temperature sensor 141.

[0064] In one or more embodiments of the present application, an oil separator is further provided in the outdoor module 10. The oil separator is provided in one-to-one correspondence with the compressor, and the oil separator is provided at the discharge end of the compressor. For example, as shown in Figure 1 The outdoor module 10 is provided with a first oil separator 105 and a second oil separator 106, the first oil separator 105 is provided at the discharge end of the first compressor 101, and the second oil separator 106 is provided at the discharge end of the second compressor 102. The functions of the first oil separator 105 and the second oil separator 106 in the air conditioning system are to separate the lubricating oil and the refrigerant. Since the first compressor 101 and the second compressor 102 need lubricating oil to reduce friction and wear to ensure normal operation, and the lubricating oil will mix with the refrigerant when the first compressor 101 and the second compressor 102 are working. The first oil separator 105 and the second oil separator 106 separate the lubricating oil from the refrigerant by the principle of physical separation (such as centrifugal force or gravity), and the separated lubricating oil is recycled and reused, while the refrigerant continues to flow. The first oil separator 105 and the second oil separator 106 are provided with a one-way valve (not shown). In one or more embodiments of the present application, the first outlet pipe 149 of the first oil separator 105 and the second outlet pipe 150 of the second oil separator 106 are connected to the switching valve 114 after being merged.

[0065] In one or more embodiments of the present application, a gas-liquid separator is further provided in the outdoor module 10. The gas-liquid separator is provided in one-to-one correspondence with the compressor. For example, as shown in Figure 1 The outdoor module 10 is provided with a first gas-liquid separator 132 and a second gas-liquid separator 133, and the first gas-liquid separator 132 and the second gas-liquid separator 133 are completely identical. The first gas-liquid separator 132 and the second gas-liquid separator 133 realize separation based on the density difference between gas and liquid. When the refrigerant containing mixed gas and liquid enters the first gas-liquid separator 132 and the second gas-liquid separator 133, due to the action of gravity, the liquid refrigerant with a larger density will sink, and the gas with a lighter density will rise. In this way, the first gas-liquid separator 132 and the second gas-liquid separator 133 can effectively separate the liquid and gaseous refrigerants. The first gas-liquid separator 132 and the second gas-liquid separator 133 are connected to each other through the upper gas equalization pipe 136 and the lower liquid equalization pipe 137.

[0066] The first U-shaped tube 134 is provided in the first gas-liquid separator 132 and is connected to the first compressor 101. The second U-shaped tube 135 is provided in the second gas-liquid separator 133 and is connected to the second compressor 102.

[0067] In one or more embodiments of the present application, a switching valve 114 is provided in the outdoor module 10. The switching valve 114 is typically a four-way valve, which allows the air conditioning system to switch between the cooling mode and the heating mode. When the air conditioning system is operating in the cooling mode, the outdoor heat exchanger 115 functions as a condenser. When the air conditioning system is operating in the heating mode, the outdoor heat exchanger 115 functions as an evaporator.

[0068] In one or more embodiments of the present application, an outdoor fan 163 (as shown in FIG. 1) is provided in the outdoor module 10. The rotational speed of the outdoor fan can be controlled to change the flow rate of air that exchanges heat with the outdoor heat exchanger 115 by adjusting the rotational speed. The outdoor fan can be an axial fan, a cross-flow fan, or other alternative fan forms. The outdoor fan is disposed adjacent to the outdoor heat exchanger 115. Figure 18

[0069] In one or more embodiments of the present application, an exhaust pressure sensor 113 is provided downstream of the first oil separator 105 and the second oil separator 106.

[0070] In the cooling operation, the outdoor module 10 forms a refrigerant circuit for the cooling operation, which is connected in sequence from the gas pipe 125 to the liquid pipe 118 with the switching valve 114 (e.g., the passage between the C port and the S port of the four-way valve), the first gas-liquid separator 132 and the second gas-liquid separator 133 in parallel, the first compressor 101 and the second compressor 102 in parallel, the switching valve 114 (e.g., the passage between the D port and the E port of the four-way valve), the outdoor heat exchanger 115, and the outdoor throttling element 116, as shown in FIG. 1. Figure 2

[0071] In the heating operation, the outdoor module forms a refrigerant circuit for the heating operation, which is connected in sequence from the liquid-side pipe to the gas-side pipe with the outdoor electronic expansion valve, the outdoor heat exchanger 115, the switching valve 114 (e.g., the passage between the E port and the S port of the four-way valve), the first gas-liquid separator 132 and the second gas-liquid separator 133 in parallel, the first compressor 101 and the second compressor 102 in parallel, and the switching valve 114 (e.g., the passage between the D port and the C port of the four-way valve).

[0072] The structure and functions of the indoor module 20 are described below.

[0073] The indoor module 20 performs the cooling operation or the heating operation using the energy for increasing the indoor temperature or the energy for decreasing the indoor temperature generated by the outdoor unit.​​

[0074] In one or more embodiments of the present application, the indoor module 20 includes a plurality of indoor heat exchangers (e.g., 120, 122, and 124) connected in parallel, each of which is matched with an indoor throttling element (e.g., 119, 121, and 123) configured to reduce the pressure of the refrigerant and expand it. A set of indoor heat exchangers and indoor throttling elements can be provided in an air conditioning room and matched with an indoor fan, which can be an axial fan, a cross-flow fan, or other forms of fans. The indoor fan is provided close to the indoor heat exchangers.

[0075] In one or more embodiments of the present application, the switching valve 114, and the first gas-liquid separator 132 and the second gas-liquid separator 133 connected in parallel guide the flow of refrigerant through the distribution pipeline 127. The distribution pipeline 127 is connected to the inlet end of the distributor 131. The distributor 131 has a plurality of outlet ends, for example, the distributor 131 can have two outlet ends, one of which is connected to the first flow guide pipe 129, and the other of which is connected to the second flow guide pipe 130, the first flow guide pipe 129 extends into the first gas-liquid separator 132, and the second flow guide pipe 130 extends into the second gas-liquid separator 133. The distribution pipeline 127 is provided with a low-pressure side pressure sensor 128.

[0076] The first oil separator 105 is in communication with the first flow guide pipe 129 through the first oil return branch 107. The first oil return branch 107 is provided with a filter 109 and a first oil return capillary tube 111. The second oil separator 106 is in communication with the second flow guide pipe 130 through the second oil return branch 108. The second oil return branch 108 is provided with a filter 110 and a second oil return capillary tube 112.

[0077] In use, there is a pressure difference between the first gas-liquid separator 132 and the second gas-liquid separator 133. This pressure difference can be very obvious, even a pressure difference of 1 KPa will cause a liquid level difference of 10 cm. Even if the equalization pipe 125 uses a Φ25.4 mm pipe diameter, the pressure difference between the first gas-liquid separator 132 and the second gas-liquid separator 133 is often more than 1 KPa, which will cause the liquid level of the oil-liquid mixture in the gas-liquid separator with high pressure to be low, and the liquid level of the oil-liquid mixture in the gas-liquid separator with low pressure to be high.

[0078] Further analysis of the oil-liquid mixture in the gas-liquid separator is carried out. In the static state, the lubricating oil and the liquid refrigerant are completely miscible, but in the dynamic state, the liquid mixture flowing into the gas-liquid separator through the first and second flow guide pipes 129 and 130 has a high content of liquid refrigerant, and the liquid refrigerant is gathered in the upper part of the oil-liquid mixture and penetrates downward with time. Therefore, the upper part of the oil-liquid mixture has a high content of liquid refrigerant and a low concentration of lubricating oil, and the bottom part of the oil-liquid mixture has a low content of liquid refrigerant and a high concentration of lubricating oil. As described above, at this time, a pressure difference exists between the first and second gas-liquid separators 132 and 133, causing the liquid level of the first gas-liquid separator 132 to be 10 cm lower than that of the second gas-liquid separator 133, so that the oil-liquid mixture with the highest concentration of lubricating oil at the bottom of the first gas-liquid separator 132 is continuously pressed into the second gas-liquid separator 133, eventually causing the liquid refrigerant in the upper part to flow in and be continuously diluted, and the concentration of the oil-liquid mixture at the bottom of the first gas-liquid separator 132 becomes lower and lower, while the concentration of the oil-liquid mixture in the second gas-liquid separator 133 becomes higher and higher. Since the first and second U-shaped tubes 134 and 135 are respectively arranged in the first and second gas-liquid separators 132 and 133 to play a role of returning oil, oil return holes are formed at the bottom of the first and second U-shaped tubes 134 and 135. Therefore, the amount of lubricating oil returned to the first compressor 101 through the first U-shaped tube 134 becomes less and less, causing the compressor to be out of oil.

[0079] To solve this problem, in one or more embodiments of the present application, a processing device 30 is also provided, as shown in Figure 4 .

[0080] As shown in Figure 5 , the hardware structure of the processing device 30 is shown in the figure. The processing device 30 includes a processor 301, a volatile memory 303, a non-volatile memory 302, a display device 304, an operation device 305, a communication interface 306, and a drive device 307, and is connected to each other through a bus 308. The processor 301 can be a special-purpose processor 301, a central processing unit, etc. The processor 301 can access the storage unit to execute instructions or application programs stored in the storage unit to realize related functions. The display device 304 is a display device 304 for displaying various information, the operation device 305 is an operation device for receiving various operations, and the drive device 307 is a hardware terminal interacting with a storage medium. In one or more embodiments of the present application, the storage medium 309 includes a medium such as a CD-ROM, a floppy disk, a magneto-optical disk, etc. to record information in an optical, electrical or magnetic manner. The storage medium 310 can also be a semiconductor memory such as a ROM, a flash memory, etc. to record information in an electrical manner.

[0081] In one or more embodiments of the present application, the processing device 30 can be a controller in the outdoor module 10.

[0082] In one or more embodiments of the present application, the processing device 30 can be implemented by a terminal device and / or a cloud server.

[0083] In one or more embodiments of the present application, part of the functions of the processing device 30 can be implemented by a controller in the outdoor module 10, and part of the functions can be implemented by a terminal device and / or a cloud server.

[0084] The network between the controller in the outdoor module 10, the terminal device and / or the cloud server can be the Internet, a cellular network, a Wi-Fi network, a low-power wide-area network (Low Power Wide Area) based on LoRa, Sigfox, NB-IoT, etc. standards and protocols, a wide-area network and a local-area network, etc.

[0085] In one or more embodiments of the present application, the processing device 30 is provided with a collection unit, a calculation unit and an estimation unit. Each of these units can be implemented by a processor running a program.

[0086] The collection unit is configured to collect operating parameters of the suction end and the discharge end of a plurality of compressors.

[0087] The calculation unit is configured to calculate the difference between the operating parameters of the suction end of a plurality of compressors, and the difference between the operating parameters of the discharge end of a plurality of compressors.

[0088] The estimation unit is configured to estimate the corresponding adjustment operating parameters from the regular operating parameters of a plurality of electrically driven execution components in the outdoor module 10 based on the difference between the operating parameters of the suction end, the difference between the operating parameters of the discharge end and the reference balance pressure estimation condition.

[0089] The reference balance pressure estimation condition is used to determine whether the pressure difference between a plurality of gas-liquid separators is in a non-equilibrium state. When the execution components in the outdoor module 10 operate according to the adjustment operating parameters, the pressure difference between a plurality of gas-liquid separators decreases.

[0090] In one or more embodiments of the present application, estimating the corresponding adjustment operating parameters from the regular operating parameters of a plurality of electrically driven execution components in the outdoor module 10 means changing the regular operating parameters based on the regular operating parameters of a plurality of electrically driven execution components in the outdoor module 10 to estimate the corresponding adjustment operating parameters.

[0091] The change can be an increase, a decrease, an adjustment, or a calculation of the corresponding adjustment operating parameters using an empirical formula or a model.

[0092] Continuing the above example, if the oil content at the bottom of the first gas-liquid separator 132 is increasingly low, the first compressor 101 connected thereto cannot be effectively supplemented with lubricating oil and is subject to oil deficiency wear, causing the operating parameters at the discharge end to be excessively high. At the same time, relatively speaking, while the amount of oil return is small, the amount of refrigerant is excessive, and the state of the refrigerant at the suction end of the compressor is in a non-superheated state, and the operating parameters at the suction end are excessively low; therefore, based on the difference between the operating parameters at the suction end, the difference between the operating parameters at the discharge end, and the reference balanced pressure estimation condition, it can be determined whether the pressure difference between the plurality of gas-liquid separators is in a non-balanced state. The estimation unit further estimates the corresponding adjustment operating parameter based on the conventional operating parameters of the plurality of electrically driven actuating components of the outdoor module 10, so as to reduce the pressure difference between the plurality of gas-liquid separators.

[0093] The present application cooperates with the acquisition unit, the calculation unit, and the estimation unit to realize accurate acquisition and calculation, and estimate the optimal adjustment operating parameter, so as to automatically reduce the pressure difference between the gas-liquid separators by real-time adjustment of the actuating components, thereby improving the stability and operating efficiency of the air conditioning system, and reducing mechanical wear and energy loss.

[0094] In one or more embodiments of the present application, the operating parameters at the suction end of the plurality of compressors are the suction temperatures of the plurality of compressors, and the operating parameters at the discharge end of the plurality of compressors are the discharge temperatures of the plurality of compressors.

[0095] In one or more embodiments of the present application, the operating parameters can also be pressure, or other parameters that can be converted based on the pressure-enthalpy diagram.

[0096] In one or more embodiments of the present application, the reference balanced pressure estimation condition is that the difference between the suction temperatures of the compressors is higher than a set temperature threshold, and the difference between the discharge temperatures of the compressors is higher than a set temperature threshold.

[0097] In one or more embodiments of the present application, the outdoor module 10 includes a plurality of adjustment branches. The adjustment branches are arranged between corresponding oil separators and gas-liquid separators. Each adjustment branch is provided with an actuating component. When the actuating component operates according to the adjustment operating parameter, the actuating component changes the flow rate of the refrigerant in at least one adjustment branch, so as to reduce the pressure difference between the plurality of gas-liquid separators.

[0098] In one or more embodiments of the present application, the actuating component is an electronic expansion valve, and the adjustment operating parameter is the opening degree of the electronic expansion valve.

[0099] When the estimation unit estimates the adjustment operating parameter, the following steps are included:

[0100] The difference between the operating parameters at the suction end and the difference between the operating parameters at the discharge end are obtained.

[0101] Based on the difference between the suction-side operating parameters and the difference between the discharge-side operating parameters, the opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with higher pressure is reduced, and the opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with lower pressure is increased.

[0102] As shown in Figure 4 The outdoor module 10 includes a first regulation branch 143 and a second regulation branch 146. The first regulation branch 143 is arranged between the first outlet pipeline 149 and the first flow guide pipe 129, and the second regulation branch 146 is arranged between the second outlet pipeline 150 and the second flow guide pipe 130. The first regulation branch 143 is provided with a first electronic expansion valve 144, and the second regulation branch 146 is provided with a second electronic expansion valve 147. The first electronic expansion valve 144 is in series with a filter 145, and the second electronic expansion valve 147 is in series with a filter 148.

[0103] When the estimation unit estimates the regulation operating parameters, the difference between the suction-side operating parameters and the difference between the discharge-side operating parameters are obtained, and based on the difference between the suction-side operating parameters and the difference between the discharge-side operating parameters, the opening degree of the electronic expansion valve (one of the first electronic expansion valve 144 and the second electronic expansion valve 147) corresponding to the one of the plurality of gas-liquid separators with higher pressure is reduced, and the opening degree of the electronic expansion valve (the other one of the first electronic expansion valve 144 and the second electronic expansion valve 147) corresponding to the one of the plurality of gas-liquid separators with lower pressure is increased.

[0104] In one or more embodiments of the present application, based on the difference between the suction-side operating parameters and the difference between the discharge-side operating parameters, the opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with higher pressure is reduced, and the opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with lower pressure is increased, which specifically includes the following steps:

[0105] The opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with higher pressure is reduced to the lower limit threshold of the opening degree, which can be completely closed, for example.

[0106] The current proportional relationship between the difference between the suction-side operating parameters and the difference between the discharge-side operating parameters is obtained.

[0107] According to a function relationship established based on a proportional relationship and an opening degree adjustment range, a fitting adjustment range corresponding to the current proportional relationship is determined; by taking the product of the opening degree of the previous electronic expansion valve and the fitting adjustment range as the actual opening degree for a plurality of times, the opening degree of the electronic expansion valve corresponding to the one with lower pressure in the plurality of gas-liquid separators is gradually increased until the opening degree of the electronic expansion valve corresponding to the one with lower pressure in the plurality of gas-liquid separators reaches the maximum opening degree, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; wherein the initial opening degree of the electronic expansion valve is the minimum flow opening degree.

[0108] In a large multi-connected air conditioning system, a sensor with very high precision is usually not selected. On the one hand, high-precision sensors have higher requirements for the working environment, are easily disturbed by temperature, humidity, electromagnetic factors, and affect the service life of the sensor; on the other hand, high-precision sensors need to be calibrated frequently, which does not meet the needs of long-term continuous use by users. However, as mentioned above, a pressure difference of 1KPa will cause a liquid level difference of 10cm, so it is necessary to accurately identify the difference between the suction end operating parameters and the difference between the discharge end operating parameters, and respond in time to dynamically correct. Therefore, in the present application, the control strategy makes up for the lack of sensor precision, and the intelligent algorithm realizes accurate control.

[0109] Firstly, the current proportional relationship between the difference between the suction end operating parameters and the difference between the discharge end operating parameters is obtained. The proportional relationship has a magnifying effect of relative change, that is, even if the absolute change of the difference between the suction end operating parameters and the difference between the discharge end operating parameters is small, the proportional relationship can magnify this small change because the ratio is a relative change, and can more sensitively reflect the subtle fluctuations of the system operating state, which is helpful to timely capture early abnormalities or trend changes in the non-equilibrium state. Secondly, the calculation of the difference parameters may also be affected by precision and drift, and through ratio calculation, the common influence factors of precision and drift can be partially offset. And according to a function relationship established based on a proportional relationship and an opening degree adjustment range, the fitting adjustment range corresponding to the current proportional relationship is determined, which can smoothly determine the adjustment operating parameter and avoid excessive adjustment and system oscillation.

[0110] Figure 6 The flow chart of one embodiment of the processing device 30 is introduced by taking temperature as an operating parameter. Taking T s1 represents the suction temperature of the first compressor 101, T s2 represents the suction temperature of the second compressor 102, T d1 represents the discharge temperature of the first compressor 101, T d2 represents the discharge temperature of the second compressor 102. The difference between the suction end operating parameters can be represented as |T s1 -T s2|, the difference between the discharge end operating parameters can be expressed as |T d1 -T d2 |.

[0111] In one or more embodiments of the present application, the reference balance pressure estimation condition can be set as |T s1 -T s2 |≥A℃ and |T d1 -T d2 |≥A℃. A is a constant, which can be pre-configured and stored. If |T s1 -T s2 |≥A℃ and |T d1 -T d2 |≥A℃ indicates that the first gas-liquid separator 132 and the second gas-liquid separator 133 are in a non-equilibrium state.

[0112] If further satisfying T s1 ≤T s2 -A℃, and T d1 ≥T d2 +A℃, the first compressor 101 has less oil return and more liquid return than the second compressor 102, the first gas-liquid separator 132 has higher internal pressure than the second gas-liquid separator 133, and the liquid level of the first gas-liquid separator 132 is low.

[0113] The ratio of the corresponding suction end operating parameter and the discharge end operating parameter difference is calculated:

[0114]

[0115] According to the function established based on the proportional relationship and the opening adjustment amplitude, the fitting adjustment amplitude ΔEV corresponding to m is determined.

[0116] The opening of the first electronic expansion valve 144 is adjusted to the minimum value, and every t minutes, the opening of the second electronic expansion valve 147 is gradually increased by taking the product of the previous second electronic expansion valve 147 opening and the fitting adjustment amplitude as the actual opening.

[0117] That is, the opening of the first electronic expansion valve 144 is adjusted to the minimum value, for example, the first electronic expansion valve 144 is executed to close valve control, and the opening of the second electronic expansion valve 147 can be expressed as PMV2(n) = PMV2(n-1)*ΔEV; wherein, i.e. the initial opening of the second electromagnetic expansion valve satisfies PMV2(1) = PMVstart, and PMVstart is the opening pulse opening of the first electronic expansion valve 144, i.e. the minimum flow opening.

[0118] Figure 7 The flow chart of one embodiment of the processing device 30 is shown in FIG. 9. If further satisfying T s2 ≤T s1-A℃, and T d2 ≥T d1 +A℃, the second compressor 102 is less oil return and more liquid return than the first compressor 101, the second gas-liquid separator 133 has higher internal pressure than the first gas-liquid separator 132, and the liquid level of the second gas-liquid separator 133 is low.

[0119] The ratio of the corresponding suction end operating parameter difference and the discharge end operating parameter difference is calculated:

[0120]

[0121] According to the function relationship established based on the proportional relationship and the opening adjustment amplitude, the fitting adjustment amplitude ΔEV corresponding to m is determined.

[0122] The opening of the second electronic expansion valve 147 is adjusted to the minimum value, and every t minutes, the opening of the first electronic expansion valve 144 is gradually increased by taking the product of the previous electronic expansion valve opening and the fitting adjustment amplitude as the actual opening.

[0123] That is, the opening of the second electronic expansion valve 147 is adjusted to the minimum value, for example, the second electronic expansion valve 147 is executed to close valve control, and the opening of the first electronic expansion valve 144 can be expressed as PMV1(n) = PMV1(n-1)*ΔEV; wherein PMV1(1), the initial opening of the first electromagnetic expansion valve, satisfies PMV1(1) = PMVstart, and PMVstart is the opening pulse opening of the first electronic expansion valve 144, that is, the minimum flow opening.

[0124] In one or more embodiments of the present application, the ΔEV sets a boundary value constraint, ΔEV∈(100%, 165%].

[0125] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening adjustment amplitude is obtained by the following method:

[0126] Under simulated conditions, the difference between the suction end operating parameters and the difference between the discharge end operating parameters are collected;

[0127] The proportional relationship of the corresponding suction end operating parameter difference and the discharge end operating parameter difference is calculated;

[0128] The opening of the electronic expansion valve corresponding to the one with higher pressure in the plurality of gas-liquid separators is reduced to the lower threshold value;

[0129] In the preset data pool, a set of adjustment amplitudes and adjustment frequencies are randomly generated; based on the adjustment frequencies, a set time length is divided into a plurality of consecutive periods, and the opening degree of the electronic expansion valve corresponding to the one of the plurality of gas-liquid separators with lower pressure is gradually increased by the product of the opening degree of the electronic expansion valve in the previous period and the random adjustment amplitude as the actual opening degree;

[0130] At the end of the preset time length, it is determined whether the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state;

[0131] If the pressure difference is no longer in the non-equilibrium state, the corresponding ratio and adjustment amplitude are recorded as effective data points;

[0132] The above process is repeated to obtain a plurality of sets of corresponding data points between the proportional relationship and the opening adjustment amplitude, and a function relationship between the proportional relationship and the opening adjustment amplitude is fitted.

[0133] The adjustment amplitudes and adjustment frequencies in the preset data pool follow preset range constraints (for example, the total adjustment amplitude cannot exceed the maximum opening degree of the electronic expansion valve), step constraints (for example, the step between adjacent adjustment amplitudes in the data pool cannot exceed a set value), historical constraints (if the system performs better at one or more adjustment amplitudes and adjustment frequencies, the probability of occurrence of the one or more adjustment amplitudes and adjustment frequencies in random generation is preferably increased), and the like. The adjustment amplitudes and adjustment frequencies in the preset data pool can be supplemented in combination with specific system and data requirements.

[0134] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening adjustment amplitude is a polynomial fitting function. Figure 8 This is an example of a polynomial fitting function.

[0135] The amplification effect of the ratio on the relative change can amplify a small relative change, which means that it is easier to capture the differences between the suction end operating parameters, the differences between the discharge end operating parameters, and the nonlinear relationship between the electronic expansion valves as the execution components in the fitting process. At the same time, the amplification effect of the ratio on the relative change can also help to reduce the influence caused by data errors or noise, thereby improving the accuracy and reliability of the fitting. Therefore, the polynomial fitting function established based on the proportional relationship and the opening adjustment amplitude can more accurately model and predict the behavior of the air conditioning system.

[0136] As shown in FIG. 1, in one or more embodiments of the present application, the execution component is an electromagnetic valve. The adjustment operating parameter is the on-off of the electromagnetic valve. Figure 9

[0137] When the adjustment operating parameter is determined, the following steps are included:

[0138] ​Acquire the differences between the operating parameters at the inhalation end and the operating parameters at the exhalation end;

[0139] Based on the differences between the operating parameters at the inhalation end and the operating parameters at the discharge end, according to the set intervention cycle, the solenoid valve corresponding to the one with the higher pressure among the multiple gas-liquid separators is closed, and the solenoid valve corresponding to the one with the lower pressure among the multiple gas-liquid separators is opened.

[0140] like Figure 9 As shown, the outdoor module 10 includes a first regulating branch 155 and a second regulating branch 159. The first regulating branch 155 is located between the first outlet pipe 149 and the first drain pipe 129, and the second regulating branch 159 is located between the second outlet pipe 150 and the second drain pipe 130. A first solenoid valve 157 is installed on the first regulating branch 155, and a second solenoid valve 161 is installed on the second regulating branch 159. The first solenoid valve 157 is connected in series with the filter 156 and the first regulating capillary tube 158, and the second solenoid valve 161 is connected in series with the filter 160 and the second regulating capillary tube 162.

[0141] Figure 10 This is a flowchart of one embodiment of the processing device 30. In one or more embodiments of this application, the reference equilibrium pressure estimation condition can be set as |T s1 -T s2 |≥A℃ and|T d1 -T d2 |≥A℃.

[0142] If T is further satisfied s1 ≤T s2 -A℃, and T d1 ≥T d2 If the temperature is +A℃, then the first compressor 101 returns less oil and more liquid than the second compressor 102. At the same time, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in an unbalanced state, and the internal pressure of the first gas-liquid separator 132 is higher than that of the second gas-liquid separator 133, and the liquid level of the first gas-liquid separator 132 is lower.

[0143] In each adjustment cycle, the first solenoid valve 157 is closed and the second solenoid valve 161 is opened.

[0144] Figure 11 A flowchart of one embodiment of the processing device 30, if T is further satisfied s2 ≤T s1 -A℃, and T d2 ≥T d1If the temperature is +A℃, then the second compressor 102 returns less oil and more liquid than the first compressor 101. At the same time, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in an unbalanced state, and the internal pressure of the second gas-liquid separator 133 is higher than that of the first gas-liquid separator 132, and the liquid level of the second gas-liquid separator 133 is lower.

[0145] During each adjustment cycle, the first solenoid valve 157 is opened and the second solenoid valve 161 is closed.

[0146] In one or more embodiments of this application, the actuating components are a plurality of compressors. The estimation unit, based on the current operating frequency of the compressors, reduces the pressure difference between the plurality of gas-liquid separators by changing the current operating frequency of the compressors.

[0147] like Figure 12 As shown, the outdoor module 10 has an regulating branch 151. The regulating branch 151 is located between the junction pipe 142 and the distribution pipe 127 after the first outlet pipe and the second outlet pipe merge. A solenoid valve 153 is installed on the regulating branch 151, and the solenoid valve 153 is connected in series with the filter 152 and the regulating capillary tube 154.

[0148] Figure 13 This is a flowchart of one embodiment of the processing device 30. In one or more embodiments of this application, the reference equilibrium pressure estimation condition can be set as |T s1 -T s2 |≥A℃ and|T d1 -T d2 |≥A℃.

[0149] If T is further satisfied s1 ≤T s2 -A℃, and T d1 ≥T d2 If the temperature is +A℃, then the first compressor 101 returns less oil and more liquid than the second compressor 102. At the same time, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in an unbalanced state, and the internal pressure of the first gas-liquid separator 132 is higher than that of the second gas-liquid separator 133, and the liquid level of the first gas-liquid separator 132 is lower.

[0150] In each adjustment cycle, control is executed to increase the frequency of the first compressor 101 until the frequency of the first compressor 101 reaches the upper frequency threshold; control is executed to decrease the frequency of the second compressor 102 until the frequency of the second compressor 102 reaches the lower frequency threshold or is no longer in an unbalanced state.

[0151] Figure 14 A flowchart of one embodiment of the processing device 30, if T is further satisfied s2 ≤T s1-A℃, and T d2 ≥T d1 If the temperature is +A℃, then the second compressor 102 returns less oil and more liquid than the first compressor 101. At the same time, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in an unbalanced state, and the internal pressure of the second gas-liquid separator 133 is higher than that of the first gas-liquid separator 132, and the liquid level of the second gas-liquid separator 133 is lower.

[0152] In each adjustment cycle, control is executed to increase the frequency of the second compressor 102 until the frequency of the second compressor 102 reaches the upper frequency threshold; control is executed to decrease the frequency of the first compressor 101 until the frequency of the first compressor 101 reaches the lower frequency threshold or is no longer in an unbalanced state.

[0153] Within each adjustment cycle, the compressor frequency is adjusted by the same amount. For example, the adjustment amount is 2Hz.

[0154] The normal operating parameters are generated according to the preset algorithms in the existing technology. For example, the electronic expansion valve and solenoid valve on the regulating branch can be controlled according to the pressure relief requirements, and the compressor operating frequency is controlled normally.

[0155] like Figure 15 As shown, in one or more embodiments of this application, the estimation unit is further configured to, in cooling mode, estimate corresponding regulating operating parameters based on the differences between the operating parameters at the suction end, the differences between the operating parameters at the discharge end, and the reference equilibrium pressure estimation condition, according to the normal operating parameters of the electrically driven actuator in the indoor module 20. When the actuator in the indoor module 20 operates according to the regulating operating parameters, the refrigerant flow rate in the distribution pipeline 127 decreases, and the pressure difference between the plurality of gas-liquid separators decreases.

[0156] In this embodiment, by increasing the superheat of the indoor module 20, the flow rate of the evaporating refrigerant is relatively reduced, thereby improving the evaporation effect; further reducing the refrigerant flow rate in the distribution pipeline 127 increases the concentration of lubricating oil in the two gas-liquid separators, so that the oil-rich layer at the bottom of the higher-pressure gas-liquid separator is not continuously diluted, thereby allowing the pressure in both to reach a balanced state after adjustment.

[0157] In one or more embodiments of this application, the actuating component is an indoor throttling element 119. Based on the current opening degree of the indoor throttling element 119, the estimation unit reduces the refrigerant flow rate in the distribution line 127 and decreases the pressure difference between the plurality of gas-liquid separators by changing the current opening degree of the indoor throttling element 119. The indoor throttling element 119 is an indoor electronic expansion valve.

[0158] In one or more embodiments of the present application, the presumption unit gradually reduces the opening degree of the indoor throttling element 119 by changing the current opening degree of the indoor throttling element 119, so that the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced, including:

[0159] obtaining the current proportional relationship between the difference between the suction end operating parameters and the difference between the discharge end operating parameters;

[0160] determining the fitting adjustment amplitude corresponding to the current proportional relationship according to the function relationship established based on the proportional relationship and the opening degree adjustment amplitude; gradually reducing the opening degree of the indoor throttling element 119 by taking the product of the previous opening degree of the indoor throttling element 119 and the fitting adjustment amplitude as the actual opening degree for a plurality of consecutive times, until the opening degree of the indoor throttling element 119 reaches the minimum opening degree, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; wherein the initial opening degree of the indoor throttling element 119 is the minimum flow opening degree.

[0161] In one or more embodiments of the present application, the function relationship based on the proportional relationship and the opening degree adjustment amplitude is obtained by the following method:

[0162] Under simulated conditions, collect the difference between the suction end operating parameters and the difference between the discharge end operating parameters;

[0163] calculate the proportional relationship corresponding to the difference between the suction end operating parameters and the difference between the discharge end operating parameters;

[0164] In a preset data pool, a set of adjustment amplitudes and adjustment frequencies are randomly generated; based on the adjustment frequency, the set time is divided into a plurality of consecutive periods, and the opening degree of the indoor throttling element 119 is gradually reduced by taking the product of the opening degree of the indoor throttling element 119 in the previous period and the random adjustment amplitude as the actual opening degree;

[0165] presume whether the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state at the end of the set time;

[0166] If it is no longer in a non-equilibrium state, record the corresponding ratio and the random adjustment amplitude as valid data points;

[0167] Repeat the above process to fit the function relationship between the proportional relationship and the opening degree adjustment amplitude.

[0168] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening degree adjustment amplitude is a polynomial fitting function, as shown in Figure 16 .

[0169] In one or more embodiments of the present application, the execution component further comprises a plurality of compressors, and the control effect is achieved by the cooperation of the compressors and the indoor throttling element 119. The presumption component is configured to continuously change the current opening of the indoor throttling element 119 for several times, so that the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced; if the pressure difference between the plurality of gas-liquid separators is still in a non-equilibrium state after the current opening of the indoor throttling element 119 is changed for several times, the current operating frequency of the compressor is changed, so that the pressure difference between the plurality of gas-liquid separators is reduced.

[0170] Figure 17 The flow chart of one embodiment of the processing device 30, in one or more embodiments of the present application, the reference equilibrium pressure presumption condition can be set as |T s1 -T s2 |≥A℃ and |T d1 -T d2 |≥A℃. A is a constant, which can be pre-configured and stored. When the above formula is satisfied, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in a non-equilibrium state.

[0171] The ratio of the difference between the corresponding suction end operating parameters and the discharge end operating parameters is calculated:

[0172]

[0173] According to the function established based on the proportional relationship and the opening adjustment amplitude, the fitting adjustment amplitude ΔEV corresponding to m is determined.

[0174] Every t minutes, the opening of the indoor throttling element 119 is gradually reduced by the product of the previous opening of the indoor throttling element 119 and the fitting adjustment amplitude. The opening of the indoor throttling element 119 can be expressed as EVI(n) = EVI(n-1)*ΔEV, until the opening of the indoor throttling element 119 reaches the minimum opening, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state. ΔEV ∈ [30%, 100%).

[0175] After several continuous adjustments, if the pressure difference between the plurality of gas-liquid separators is still in a non-equilibrium state, the control of reducing the frequency of the first compressor 101 and the second compressor 102 is performed in each adjustment period until it is no longer in a non-equilibrium state. After several continuous adjustments, if the pressure difference between the plurality of gas-liquid separators is still in a non-equilibrium state, the air conditioning system is controlled to stop.

[0176] In each adjustment period, the adjustment amplitude of the compressor frequency is the same. For example, the adjustment amplitude is 3 Hz.

[0177] AsFigure 18 As shown, in one or more embodiments of the present application, the estimating unit is further configured to estimate the corresponding adjustment operating parameter according to the normal operating parameter of the electrically driven executing component in the outdoor module based on the difference between the suction end operating parameters, the difference between the discharge end operating parameters and the reference balance pressure estimation condition in the heating mode. When the executing component in the outdoor module operates according to the adjustment operating parameter, the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced.

[0178] In the present embodiment, by increasing the superheat degree of the outdoor module, the evaporation effect is improved by relatively reducing the flow of evaporated refrigerant; further reducing the refrigerant flow in the distribution pipeline 127, and increasing the concentration of lubricating oil in the two gas-liquid separators, so that the oil-rich layer at the bottom of the gas-liquid separator with higher pressure is not continuously diluted, so that the pressure in the two is adjusted to reach a balanced state.

[0179] In one or more embodiments of the present application, the executing component is an outdoor fan. The estimating unit changes the current speed of the outdoor fan based on the current speed of the outdoor fan, so that the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced.

[0180] In one or more embodiments of the present application, the executing component is an outdoor throttling element. The estimating unit changes the current opening of the outdoor throttling element based on the current opening of the outdoor throttling element, so that the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced. The outdoor throttling element is an indoor electronic expansion valve.

[0181] In one or more embodiments of the present application, the estimating unit changes the current opening of the outdoor throttling element, so that the refrigerant flow in the distribution pipeline 127 is reduced, and the pressure difference between the plurality of gas-liquid separators is reduced, including:

[0182] Obtaining the current proportional relationship between the difference between the suction end operating parameters and the difference between the discharge end operating parameters;

[0183] According to the function relationship established based on the proportional relationship and the opening adjustment amplitude, determine the fitting adjustment amplitude corresponding to the current proportional relationship; gradually reduce the opening of the outdoor throttling element 116 by taking the product of the previous outdoor throttling element opening and the fitting adjustment amplitude as the actual opening for a plurality of times, until the opening of the outdoor throttling element 116 reaches the minimum opening, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; wherein the initial opening of the outdoor throttling element 116 is the minimum flow opening.

[0184] In one or more embodiments of the present application, the function relationship between the proportional relationship and the opening adjustment amplitude is obtained by the following method:

[0185] Under the simulation condition, the difference between the suction end operating parameters and the difference between the discharge end operating parameters are collected;

[0186] The proportional relationship of the corresponding suction end operating parameter difference and the discharge end operating parameter difference is calculated;

[0187] In the preset data pool, a set of adjustment amplitudes and adjustment frequencies are randomly generated; based on the adjustment frequency, the set time is divided into a plurality of consecutive periods, and the opening of the outdoor throttling element 116 is gradually reduced by the product of the opening of the outdoor throttling element 116 in the above one period and the random adjustment amplitude as the actual opening;

[0188] At the end of the set time, it is determined whether the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state;

[0189] If it is no longer in a non-equilibrium state, the corresponding ratio and the random adjustment amplitude are recorded as effective data points;

[0190] The above process is repeated to fit the function relationship between the proportional relationship and the opening adjustment amplitude.

[0191] In one or more embodiments of the present application, the function relationship established based on the proportional relationship and the opening adjustment amplitude is a polynomial fitting function.

[0192] In one or more embodiments of the present application, the execution component further includes a plurality of compressors. The presumption component is configured to continuously change the current opening of the outdoor throttling element 116 for a plurality of times to reduce the refrigerant flow in the distribution pipeline 127 and the pressure difference between the plurality of gas-liquid separators; if the pressure difference between the plurality of gas-liquid separators is still in a non-equilibrium state after changing the current opening of the outdoor throttling element 116 for a plurality of times, the current operating frequency of the compressor is changed to reduce the pressure difference between the plurality of gas-liquid separators.

[0193] Figure 19 The flowchart of one embodiment of the processing device 30, in one or more embodiments of the present application, the reference equilibrium pressure presumption condition can be set as |T s1 -T s2 |≥A℃ and |T d1 -T d2 |≥A℃. A is a constant, which can be pre-configured and stored. When the above formula is satisfied, the first gas-liquid separator 132 and the second gas-liquid separator 133 are in a non-equilibrium state.

[0194] The ratio of the difference between the corresponding suction-side operating parameter and the discharge-side operating parameter is calculated:

[0195]

[0196] In each adjustment cycle, the control of increasing the outdoor fan speed is executed until the highest outdoor fan speed is reached or the unbalanced state is no longer present.

[0197] In each adjustment cycle, the adjustment range of the fan speed is the same. For example, the adjustment range is 5% of the highest speed.

[0198] After the fan speed adjustment is executed for several times in succession, if the pressure difference between the plurality of gas-liquid separators is still in the unbalanced state, the fitting adjustment range ΔEV corresponding to m is determined according to the function established based on the proportional relationship and the adjustment range of the opening degree.

[0199] Every t minutes, the opening degree of the outdoor throttling element 116 is gradually reduced by taking the product of the previous opening degree of the outdoor throttling element 116 and the fitting adjustment range as the actual opening degree, and the opening degree of the outdoor throttling element 116 can be expressed as EVO(n) = EVO(n-1)*ΔEV, until the opening degree of the outdoor throttling element 116 reaches the minimum opening degree or the pressure difference between the plurality of gas-liquid separators is no longer in the unbalanced state. ΔEV ∈ [30%, 100%).

[0200] After the adjustment is executed for several times in succession, if the pressure difference between the plurality of gas-liquid separators is still in the unbalanced state, the control of reducing the frequency of the first compressor 101 and the second compressor 102 is executed in each adjustment cycle until the unbalanced state is no longer present. After the adjustment is executed for several times in succession, if the pressure difference between the plurality of gas-liquid separators is still in the unbalanced state, the control of stopping the air conditioning system is executed.

[0201] The conventional operating parameters are operating parameters generated according to the algorithm preset in the prior art, including the opening degree of the indoor electronic expansion valve, the opening degree of the outdoor electronic expansion valve, and the operating frequency of the compressor.

[0202] In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0203] The above merely describes specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An air conditioning system, comprising: an outdoor module having: a plurality of compressors; a switching valve; a plurality of oil separators respectively arranged at discharge ends of the compressors; and a plurality of gas-liquid separators respectively arranged at suction ends of the compressors, and a liquid equalizing pipe arranged between the gas-liquid separators; characterized in that further comprising: a processing device having: a collecting unit configured to collect operating parameters of the suction ends and the discharge ends of the plurality of compressors; a calculating unit configured to calculate differences between the operating parameters of the suction ends and differences between the operating parameters of the discharge ends; and an estimating unit configured to estimate, based on the differences between the operating parameters of the suction ends, the differences between the operating parameters of the discharge ends, and a reference balanced pressure estimation condition, adjustment operating parameters of a plurality of electrically driven execution components in the outdoor module from normal operating parameters of the execution components; wherein the reference balanced pressure estimation condition is used to determine whether a pressure difference between the plurality of gas-liquid separators is in an unbalanced state, and the pressure difference between the plurality of gas-liquid separators is reduced when the execution components in the outdoor module operate according to the adjustment operating parameters.

2. The air conditioning system according to claim 1, characterized in that: the outdoor module comprises a plurality of adjustment branches arranged between corresponding oil separators and gas-liquid separators; each of the adjustment branches is provided with one of the execution components; and the execution components reduce the pressure difference between the plurality of gas-liquid separators by changing a refrigerant flow in at least one of the adjustment branches when the execution components operate according to the adjustment operating parameters.

3. The air conditioning system according to claim 2, characterized in that: the execution components are electronic expansion valves, and the adjustment operating parameters are opening degrees of the electronic expansion valves; the estimation of the adjustment operating parameters comprises the following steps: obtaining the differences between the operating parameters of the suction ends and the differences between the operating parameters of the discharge ends; based on the differences between the operating parameters of the suction ends and the differences between the operating parameters of the discharge ends, reducing the opening degree of an electronic expansion valve corresponding to a gas-liquid separator with a higher pressure among the plurality of gas-liquid separators, and increasing the opening degree of an electronic expansion valve corresponding to a gas-liquid separator with a lower pressure among the plurality of gas-liquid separators.

4. The air conditioning system according to claim 3, characterized in that: based on the differences between the operating parameters of the suction ends and the differences between the operating parameters of the discharge ends, reducing the opening degree of an electronic expansion valve corresponding to a gas-liquid separator with a higher pressure among the plurality of gas-liquid separators, and increasing the opening degree of an electronic expansion valve corresponding to a gas-liquid separator with a lower pressure among the plurality of gas-liquid separators, comprises: reducing the opening degree of the electronic expansion valve corresponding to the gas-liquid separator with the higher pressure among the plurality of gas-liquid separators to a lower threshold of the opening degree; obtaining a current proportional relationship between the differences between the operating parameters of the suction ends and the differences between the operating parameters of the discharge ends; and ​ ​ According to a function relationship established based on a proportional relationship and an opening degree adjustment range, a fitting adjustment range corresponding to the current proportional relationship is determined; by taking the product of the opening degree of the previous electronic expansion valve and the fitting adjustment range as the actual opening degree, the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators is gradually increased until the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators reaches the maximum opening degree, or the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state; wherein the initial opening degree of the electronic expansion valve is the minimum flow opening degree.

5. The air conditioning system of claim 4, wherein: The function relationship established based on the proportional relationship and the opening degree adjustment range is obtained by: Under simulated conditions, differences between suction end operating parameters and differences between discharge end operating parameters are collected; A proportional relationship corresponding to the differences between the suction end operating parameters and the differences between the discharge end operating parameters is calculated; The opening degree of the electronic expansion valve corresponding to the one with higher pressure among the plurality of gas-liquid separators is reduced to a lower threshold value; In a preset data pool, a set of adjustment ranges and adjustment frequencies are randomly generated; based on the adjustment frequencies, a set time is divided into a plurality of consecutive periods, and by taking the product of the opening degree of the electronic expansion valve in the previous period and the random adjustment range as the actual opening degree, the opening degree of the electronic expansion valve corresponding to the one with lower pressure among the plurality of gas-liquid separators is gradually increased; It is determined whether the pressure difference between the plurality of gas-liquid separators is no longer in a non-equilibrium state at the end of the set time; If it is no longer in a non-equilibrium state, the corresponding ratio and adjustment range are recorded as valid data points; A plurality of valid data points are obtained, and a function relationship between the proportional relationship and the opening degree adjustment range is fitted.

6. The air conditioning system of claim 4, wherein: The function relationship established based on the proportional relationship and the opening degree adjustment range is a polynomial fitting function.

7. The air conditioning system of claim 2, wherein: The execution component is an electromagnetic valve, and the adjusted operating parameter is the on-off of the electromagnetic valve; When the adjusted operating parameter is determined, the following steps are included: Differences between suction end operating parameters and differences between discharge end operating parameters are obtained; Based on the differences between the suction end operating parameters and the differences between the discharge end operating parameters, the electromagnetic valve corresponding to the one with higher pressure among the plurality of gas-liquid separators is closed and the electromagnetic valve corresponding to the one with lower pressure among the plurality of gas-liquid separators is opened according to a set intervention period.

8. The air conditioning system of claim 1, wherein: The execution component is a plurality of compressors; when the execution component operates according to the adjusted operating parameter, the execution component reduces the pressure difference between the plurality of gas-liquid separators by changing the current operating frequency of the compressor.

9. The air conditioning system of any one of claims 1 to 8, wherein: The difference between the suction end operating parameters is the difference in compressor suction temperature; and the difference between the discharge end operating parameters is the difference in compressor discharge temperature.

10. The air conditioning system according to any one of claims 1 to 8, characterized in that: the reference balance pressure estimation condition is that the difference in the suction temperature of the compressor is higher than a set temperature threshold and the difference in the discharge temperature of the compressor is higher than a set temperature threshold.

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