Air conditioning system and control method thereof

Abstract

This application provides an air conditioning system and its control method. The air conditioning system includes a variable frequency drive module, a compressor, an oil-gas separator, a gas-liquid separator, a four-way valve, an outdoor heat exchanger, and an indoor heat exchanger. The electronic control board of the variable frequency drive module is communicatively connected to the compressor. The compressor's outlet is connected to the refrigerant inlet of the oil-gas separator. The oil outlet of the oil-gas separator is connected to the compressor's inlet via a main oil return pipe. The oil outlet of the oil-gas separator is connected to the inlet of the gas-liquid separator via an auxiliary oil return pipe. The four-way valve connects the refrigerant outlet of the oil-gas separator, the inlet of the gas-liquid separator, the refrigerant inlet of the outdoor heat exchanger, and the refrigerant outlet of the indoor heat exchanger, respectively. The refrigerant outlet of the outdoor heat exchanger is connected to the refrigerant inlet of the indoor heat exchanger via a condenser pipe. Both the condenser pipe and the main oil return pipe are partially located within the radiator of the variable frequency drive module. The air conditioning system and its control method of this application can effectively prevent condensation from occurring on the variable frequency drive module and improve the energy efficiency of the air conditioning system.

Description

Technical Field

[0001] This application belongs to the field of air conditioning technology, and in particular relates to an air conditioning system and its control method. Background Technology

[0002] In recent years, variable frequency compressors have been developing towards higher speed, larger capacity, and higher energy efficiency. The requirements for miniaturization and high reliability of variable frequency drive modules are also gradually increasing. Variable frequency drive modules generate a lot of heat. Air conditioning systems often use refrigerant cooling devices to reduce the temperature of variable frequency drive modules. However, under high humidity conditions, variable frequency drive modules are prone to condensation problems, which can lead to short circuits.

[0003] Common anti-condensation control schemes for air conditioner inverter drive modules involve setting a threshold for comparing the inverter drive module temperature with the ambient dew point temperature. When the unit enters anti-condensation control, the air conditioning system reduces the opening of the outdoor unit's electronic expansion valve and controls the compressor to start running. However, this control scheme affects user comfort and increases the energy consumption of the air conditioner. Summary of the Invention

[0004] This application provides an air conditioning system and its control method to solve the problems of existing air conditioning inverter drive module anti-condensation control schemes affecting user comfort and increasing air conditioning energy consumption.

[0005] In a first aspect, embodiments of this application provide an air conditioning system, including a variable frequency drive module, a compressor, an oil-gas separator, a gas-liquid separator, a four-way valve, an outdoor heat exchanger, and an indoor heat exchanger. The variable frequency drive module includes an electronic control board and a radiator mounted on the electronic control board. The variable frequency drive module is communicatively connected to the compressor. The compressor's outlet is connected to the refrigerant inlet of the oil-gas separator. The oil outlet of the oil-gas separator is connected to the compressor's inlet via a main oil return pipe. The oil outlet of the oil-gas separator is connected to the gas-liquid separator's inlet via an auxiliary oil return pipe. The four-way valve connects the refrigerant outlet of the oil-gas separator, the gas-liquid separator's inlet, the outdoor heat exchanger's refrigerant inlet, and the indoor heat exchanger's refrigerant outlet. The outdoor heat exchanger's refrigerant outlet is connected to the indoor heat exchanger's refrigerant inlet via a condenser pipe. Both the condenser pipe and the main oil return pipe are partially disposed within the radiator.

[0006] Optionally, the portion of the condenser pipe located in the radiator is parallel to the portion of the main oil return pipe located in the radiator, and the refrigerant flow direction in the condenser pipe is the same as or opposite to the oil flow direction in the main oil return pipe.

[0007] Optionally, both the portion of the condenser pipe disposed in the radiator and the portion of the main oil return pipe disposed in the radiator are U-shaped, and the U-shaped portion of the condenser pipe is located inside the U-shaped portion of the main oil return pipe.

[0008] Optionally, a main return oil valve is provided on the main return oil pipe, and an auxiliary return oil valve is provided on the auxiliary return oil pipe; the air conditioning system also includes a controller, an outdoor temperature sensor for detecting the outdoor ambient temperature, a module temperature sensor for detecting the temperature of the variable frequency drive module, and a refrigerant temperature sensor for detecting the refrigerant temperature in the condenser pipe. The outdoor temperature sensor, the module temperature sensor, the refrigerant temperature sensor, the main return oil valve, and the auxiliary return oil valve are all communicatively connected to the controller.

[0009] Optionally, the radiator includes a heat sink plate and heat sink fins. The heat sink plate is disposed on the electronic control board, the heat sink fins are disposed on the heat sink plate, and the condenser pipe and the main oil return pipe are both partially disposed in the heat sink plate.

[0010] Optionally, the variable frequency drive module includes a first variable frequency drive module and a second variable frequency drive module; the compressor includes a first compressor and a second compressor; the first compressor is communicatively connected to the first variable frequency drive module, and the second compressor is communicatively connected to the second variable frequency drive module; the main oil return pipe includes a first main oil return pipe and a second main oil return pipe; the oil outlet of the oil-gas separator is connected to the air inlet of the first compressor through the first main oil return pipe, and the oil outlet of the oil-gas separator is connected to the air inlet of the second compressor through the second main oil return pipe; a portion of the first main oil return pipe is disposed in the radiator of the first variable frequency drive module, a portion of the second main oil return pipe is disposed in the radiator of the second variable frequency drive module, and a portion of the condenser pipe is disposed in the radiators of both the first and second variable frequency drive modules.

[0011] Optionally, the variable frequency drive module includes a first variable frequency drive module and a second variable frequency drive module; the compressor includes a first compressor and a second compressor; the first compressor is communicatively connected to the first variable frequency drive module, and the second compressor is communicatively connected to the second variable frequency drive module; the main oil return pipe includes a first main oil return pipe and a second main oil return pipe; the oil outlet of the oil-gas separator is connected to the air inlet of the first compressor through the first main oil return pipe, and the oil outlet of the oil-gas separator is connected to the air inlet of the second compressor through the second main oil return pipe; a portion of the first main oil return pipe is disposed in the radiator of the second variable frequency drive module, a portion of the second main oil return pipe is disposed in the radiator of the first variable frequency drive module, and a portion of the condenser pipe is disposed in the radiators of both the first and second variable frequency drive modules.

[0012] Secondly, this application embodiment also provides a control method for an air conditioning system, applied to the aforementioned air conditioning system. A main oil return valve is provided on the main oil return pipe of the air conditioning system, and an auxiliary oil return valve is provided on the auxiliary oil return pipe of the air conditioning system. The control method includes the following steps: acquiring the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe, and the temperature TS of the frequency converter drive module; and controlling the opening degree of the main oil return valve and the auxiliary oil return valve according to TH, TL, and TS.

[0013] Optionally, controlling the opening degree of the main return valve and the auxiliary return valve according to TH, TL, and TS includes:

[0014] When TH≥T1 and TS>(TL+T2), the main return valve is closed and the auxiliary return valve is opened to the maximum opening Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2.

[0015] When TH < T1 and TS > (TL + T2), both the main return valve and the auxiliary return valve are opened. The opening degree of the main return valve is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening degree of the auxiliary return valve is F3 = F * K2. Where Fq is the current opening degree of the main return valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0016] When TH < T1 and (TL + T3) < TS < (TL + T2), both the main return valve and the auxiliary return valve are opened. The opening degree of the main return valve is F = Fq + Fb, Fb = (TS - TL) * K3, and the opening degree of the auxiliary return valve is F3 = F * K4. Where T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1.

[0017] When TH < T1 and TS < (TL + T3), the main return valve is controlled to open to the maximum opening Fmax, and the auxiliary return valve is controlled to open. The opening of the auxiliary return valve is F3 = Fmax * K5, where K5 is the fifth proportional coefficient and K5 < K4.

[0018] When TH < T1 and TS > (TL + T4), the opening degree of the main return oil valve and the auxiliary return oil valve is restored to the corresponding temperature range control mentioned above, where T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

[0019] Optional settings: T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4.

[0020] Thirdly, this application embodiment also provides a control method for an air conditioning system, applied to the above-mentioned air conditioning system. The compressor in the air conditioning system includes a first compressor and a second compressor. The variable frequency drive module includes a first variable frequency drive module that is communicatively connected to the first compressor and a second variable frequency drive module that is communicatively connected to the second compressor. The main oil return pipe includes a first main oil return pipe that is connected to the first compressor and a second main oil return pipe that is connected to the second compressor. A first main oil return valve is provided on the first main oil return pipe, a second main oil return valve is provided on the second main oil return pipe, and an auxiliary oil return valve is provided on the auxiliary oil return pipe.

[0021] The control method includes the following steps: acquiring the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe, the temperature TS1 of the first frequency converter drive module, and the temperature TS2 of the second frequency converter drive module; and controlling the opening degree of the first main return oil valve, the second main return oil valve, and the auxiliary return oil valve according to TH, TL, TS1, and TS2.

[0022] Optionally, controlling the opening degrees of the first main return valve, the second main return valve, and the auxiliary return valve according to TH, TL, TS1, and TS2 includes:

[0023] When TH≥T1 and max(TS1,TS2)>(TL+T2), the first main return valve and the second main return valve are controlled to close, and the auxiliary return valve is controlled to open to the maximum opening degree Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2.

[0024] When TH < T1 and max(TS1, TS2) > (TL + T2), the first main return valve, the second main return valve, and the auxiliary return valve are all opened. The opening degree of the first main return valve is F1 = Fq1 - Fb1, Fb1 = (TS1 - TL) * K1, the opening degree of the second main return valve is F2 = Fq2 - Fb2, Fb2 = (TS2 - TL) * K1, and the opening degree of the auxiliary return valve is F3 = min(F1, F2) * K2, where Fq is the current opening degree of the first main return valve, Fq2 is the current opening degree of the second main return valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0025] When TH < T1, and max (TS1, TS2) < (TL + T2) and min (TS1, TS2) > (TL + T3), the first main return valve, the second main return valve, and the auxiliary return valve are all opened. The opening degree of the first main return valve is F1 = Fq1 + Fb1, Fb1 = (TS1 - TL) * K3, the opening degree of the second main return valve is F2 = Fq2 + Fb2, Fb2 = (TS2 - TL) * K3, and the opening degree of the auxiliary return valve is F3 = min(F1, F2) * K4. Wherein, T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1.

[0026] When TH < T1 and min (TS1, TS2) < (TL + T3), the main return valve on the main return pipe corresponding to the smaller of TS1 and TS2 is controlled to open to the maximum opening degree Fmax, and the auxiliary return valve is controlled to open. The opening degree of the auxiliary return valve F3 = Fmax * K5, where K5 is the fifth proportional coefficient and K5 < K4.

[0027] When TH < T1 and min (TS1, TS2) > (TL + T4), the opening of the first main return valve, the second main return valve and the auxiliary return valve are restored to the corresponding temperature range control mentioned above, where T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

[0028] Optional settings: T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4.

[0029] Fourthly, this application embodiment also provides a control method for an air conditioning system, applied to the above-mentioned air conditioning system. The compressor in the air conditioning system includes a first compressor communicatively connected to the first compressor and a second compressor communicatively connected to the second compressor. The variable frequency drive module includes a first variable frequency drive module and a second variable frequency drive module. The main oil return pipe includes a first main oil return pipe disposed on the radiator of the second variable frequency drive module and a second main oil return pipe disposed on the radiator of the first variable frequency drive module. A first main oil return valve is disposed on the first main oil return pipe, a second main oil return valve is disposed on the second main oil return pipe, and an auxiliary oil return valve is disposed on the auxiliary oil return pipe.

[0030] The control method includes the following steps: controlling the first compressor and the second compressor to not operate simultaneously; acquiring the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser tube, and the temperature TS of the variable frequency drive module corresponding to the operating compressor, wherein the operating compressor refers to one of the first compressor and the second compressor, the first compressor corresponds to the second variable frequency drive module, and the second compressor corresponds to the first variable frequency drive module; controlling the opening degree of the main oil return valve and the auxiliary oil return valve on the main oil return pipe corresponding to the operating compressor according to TH, TL, and TS, wherein the first compressor corresponds to the first main oil return pipe, and the second compressor corresponds to the second main oil return pipe.

[0031] Optionally, controlling the opening degree of the main return oil valve and the auxiliary return oil valve on the main return oil pipe corresponding to the operating compressor according to TH, TL, and TS includes:

[0032] When TH≥T1 and TS>(TL+T2), the main return oil valve on the main return oil pipe corresponding to the running compressor is closed, and the auxiliary return oil valve is opened to the maximum opening degree Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2.

[0033] When TH < T1 and TS > (TL + T2), the main return oil valve and the auxiliary return oil valve on the main return oil pipe corresponding to the operating compressor are both opened. The opening degree of the main return oil valve is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening degree of the auxiliary return oil valve is F3 = F * K2. Wherein, Fq is the current opening degree of the main return oil valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0034] When TH < T1 and (TL+T3) < TS < (TL+T2), the main return oil valve and the auxiliary return oil valve on the main return oil pipe corresponding to the operating compressor are both opened. The opening degree of the main return oil valve is F = Fq - Fb, Fb = (TS - TL) * K3, and the opening degree of the auxiliary return oil valve is F3 = F * K4. Where T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1.

[0035] When TH < T1 and TS < (TL + T3), the main oil return valve corresponding to the running compressor is controlled to open to the maximum opening degree Fmax, and the auxiliary oil return valve is controlled to close. If TS < (TL + T3) lasts for a preset time t, the first compressor and the second compressor are controlled to run alternately. The opening degree of the main oil return valve and the auxiliary oil return valve on the main oil return pipe corresponding to the running compressor is controlled according to the above temperature range, and the main oil return valve on the main oil return pipe corresponding to the non-running compressor is controlled to close.

[0036] During the alternating operation of the first compressor and the second compressor, when TH < T1 and TS > (TL + T4), the alternating operation of the first compressor and the second compressor is stopped, and the operation of the first compressor and / or the second compressor is controlled according to the capacity requirements of the air conditioning system, wherein T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

[0037] Optional settings: T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, t=30min.

[0038] The air conditioning system provided in this application embodiment, by placing both the main oil return pipe and the condenser pipe in the radiator of the inverter drive module, allows the oil in the main oil return pipe to exchange heat with the refrigerant in the condenser pipe, thereby regulating the temperature of the inverter drive module within a suitable temperature range and preventing condensation. Simultaneously, the refrigerant in the condenser pipe lowers the oil temperature in the oil return pipe, increasing the compressor's suction capacity and improving the air conditioning system's energy efficiency, avoiding impacts on user comfort and increased energy consumption. Furthermore, by setting an auxiliary oil return pipe, the compressor's oil return volume can be supplemented, preventing insufficient compressor demand due to reduced oil return volume in the main oil return pipe during inverter drive module temperature regulation.

[0039] The air conditioning system control method provided in this application determines the heat dissipation effect and condensation risk of the inverter drive module based on the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe, and the temperature TS of the inverter drive module. By controlling the opening of each oil return valve, the temperature of the inverter drive module and the amount of oil returned by the compressor are controlled to meet the requirements, so that the temperature of the inverter drive module is kept in a suitable temperature range to prevent condensation. At the same time, the temperature in the main oil return pipe is cooled, which increases the air intake of the compressor and improves the energy efficiency of the air conditioning system, avoiding affecting user comfort and increasing the energy consumption of air conditioning operation. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0042] Figure 1 This is a schematic diagram of the structure of an air conditioning system provided in an embodiment of this application.

[0043] Figure 2 This is a schematic diagram of a first partial structure of an air conditioning system provided in an embodiment of this application.

[0044] Figure 3 This is a schematic diagram of a second partial structure of an air conditioning system provided in an embodiment of this application.

[0045] Figure 4 This is a first flowchart of a control method for an air conditioning system provided in an embodiment of this application.

[0046] Figure 5 This is a second flowchart of a control method for an air conditioning system provided in an embodiment of this application.

[0047] Figure 6 A third flowchart of the control method for an air conditioning system provided in an embodiment of this application.

[0048] Explanation of icon numbers:

[0049] 10. Variable frequency drive module; 11. Electronic control board; 12. Radiator; 121. Heat sink plate; 1211. Sub-heat sink plate; 122. Heat sink fins; 14. First variable frequency drive module; 15. Second variable frequency drive module; 21. First compressor; 22. Second compressor; 31. Oil-gas separator; 32. Gas-liquid separator; 40. Four-way valve; 51. Outdoor heat exchanger; 52. Indoor heat exchanger; 60. Main oil return pipe; 61. First main oil return pipe; 62. Second main oil return pipe; 63. First main oil return valve; 64. Second main oil return valve; 70. Auxiliary oil return pipe; 71. Auxiliary oil return valve; 80. Condenser pipe; 91. Outdoor temperature sensor; 92. Refrigerant temperature sensor. Detailed Implementation

[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0051] Example 1

[0052] Embodiment 1 of this application provides an air conditioning system, such as Figures 1-3 As shown, the air conditioning system includes a variable frequency drive module 10, a compressor, an oil-gas separator 31, a gas-liquid separator 32, a four-way valve 40, an outdoor heat exchanger 51, and an indoor heat exchanger 52. The variable frequency drive module 10 includes an electronic control board 11 and a radiator 12 mounted on the electronic control board 11. The variable frequency drive module 10 is communicatively connected to the compressor. The compressor's outlet is connected to the refrigerant inlet of the oil-gas separator 31, and the oil outlet of the oil-gas separator 31 is connected to the compressor via a main oil return pipe 60. The oil outlet of the oil-gas separator 31 is connected to the inlet of the gas-liquid separator 32 via an auxiliary oil return pipe 70. The four-way valve 40 is connected to the refrigerant outlet of the oil-gas separator 31, the inlet of the gas-liquid separator 32, the refrigerant inlet of the outdoor heat exchanger 51, and the refrigerant outlet of the indoor heat exchanger 52, respectively. The refrigerant outlet of the outdoor heat exchanger 51 is connected to the refrigerant inlet of the indoor heat exchanger 52 via a condenser pipe 80. The condenser pipe 80 and the main oil return pipe 60 are both partially installed in the radiator 12.

[0053] The air conditioning system provided in this application embodiment, by placing both the main oil return pipe 60 and the condenser pipe 80 in the radiator 12 of the inverter drive module 10, allows the oil in the main oil return pipe 60 to exchange heat with the refrigerant in the condenser pipe 80, thereby regulating the temperature of the inverter drive module 10 within a suitable temperature range, preventing condensation in the inverter drive module 10, achieving anti-condensation control of the air conditioning system under high humidity conditions, ensuring the reliability of the inverter drive module 10. At the same time, the refrigerant in the condenser pipe 80 lowers the oil temperature in the oil return pipe, increasing the compressor's suction volume, thereby improving the energy efficiency of the air conditioning system, avoiding impact on user comfort and increased energy consumption during air conditioning operation. By setting an auxiliary oil return pipe 70, the oil return volume of the compressor can be supplemented, preventing insufficient compressor demand due to reduced oil return volume in the main oil return pipe 60 during the temperature adjustment process of the inverter drive module 10.

[0054] Optionally, the portion of the condenser tube 80 located in the radiator 12 is parallel to the portion of the main oil return pipe 60 located in the radiator 12 to improve heat exchange efficiency; the refrigerant flow direction within the condenser tube 80 is the same as the oil flow direction within the main oil return pipe 60 (e.g., ...). Figure 3 (as shown) or the opposite (as shown) Figure 2 (as shown) Figure 2 and Figure 3 The dashed arrows indicate the direction of refrigerant flow, while the solid arrows indicate the direction of oil flow. By setting the refrigerant flow direction in the condenser tube 80 to be opposite to the oil flow direction in the main return oil pipe 60, the heat exchange effect can be enhanced.

[0055] Optionally, both the portion of the condenser pipe 80 located in the radiator 12 and the portion of the main oil return pipe 60 located in the radiator 12 are U-shaped, and the U-shaped portion of the condenser pipe 80 is located inside the U-shaped portion of the main oil return pipe 60, that is, the U-shaped portion of the main oil return pipe 60 surrounds the U-shaped portion of the condenser pipe 80, which can further enhance the heat exchange effect and more effectively control the temperature of the frequency converter drive module 10.

[0056] Optional, such as Figure 1As shown, a main oil return valve is installed on the main oil return pipe 60, and an auxiliary oil return valve 71 is installed on the auxiliary oil return pipe 70. Both the main oil return valve and the auxiliary oil return pipe 70 can be expansion valves. The air conditioning system also includes a controller, an outdoor temperature sensor 91 for detecting the outdoor ambient temperature, a module temperature sensor for detecting the temperature of the inverter drive module 10, and a refrigerant temperature sensor 92 for detecting the refrigerant temperature inside the condenser coil 80. The outdoor temperature sensor 91, module temperature sensor, refrigerant temperature sensor 92, main oil return valve, and auxiliary oil return valve 71 are all communicatively connected to the controller. Optionally, the outdoor temperature sensor 91, module temperature sensor, and refrigerant temperature sensor 92 can all be temperature sensors or temperature sensing bulbs. The air conditioning system can control the opening of each return oil valve (i.e., the main return oil valve and the auxiliary return oil valve 71) through the controller based on the outdoor ambient temperature detected by the outdoor temperature detector 91, the refrigerant temperature detected by the refrigerant temperature detector 92, and the temperature of the variable frequency drive module 10 detected by the module temperature detector. This controls the temperature of the variable frequency drive module 10 and the amount of oil returned by the compressor to meet the requirements, keeping the temperature of the variable frequency drive module 10 within a suitable temperature range to prevent condensation. At the same time, the temperature in the main return oil pipe 60 is cooled to increase the compressor's suction volume, thereby improving the energy efficiency of the air conditioning system and avoiding affecting user comfort and increasing the energy consumption of the air conditioning operation.

[0057] Optional, such as Figure 2 and Figure 3 As shown, the radiator 12 includes a heat sink 121 and heat sink fins 122. The heat sink 121 is mounted on the control board 11, and the heat sink fins 122 are mounted on the heat sink 121. The condenser pipe 80 and the main oil return pipe 60 are both partially disposed within the heat sink 121. By using the heat sink fins 122, the heat dissipation effect of the frequency converter drive module 10 can be enhanced through air-cooled heat exchange. Specifically, the heat sink 121 includes two sub-heat sinks 1211, with a portion of the condenser pipe 80 and a portion of the main oil return pipe 60 sandwiched between the two sub-heat sinks 1211.

[0058] Optionally, the air conditioning system can be a dual-compressor system or a single-compressor system, meaning the air conditioning system can include two compressors or one compressor. When the air conditioning system is a dual-compressor system, the variable frequency drive module 10 includes a first variable frequency drive module 14 and a second variable frequency drive module 15. The compressors include a first compressor 21 and a second compressor 22. The first compressor 21 is communicatively connected to the first variable frequency drive module 14, and the second compressor 22 is communicatively connected to the second variable frequency drive module 15. The main oil return pipe 60 includes a first main oil return pipe 61 and a second main oil return pipe 62. The oil outlet of the oil-gas separator 31 is connected to the air inlet of the first compressor 21 through the first main oil return pipe 61. The oil outlet of the separator 31 is connected to the air inlet of the second compressor 22 via the second main oil return pipe 62. The first main oil return pipe 61 is partially disposed in the radiator 12 of the first variable frequency drive module 14, and the second main oil return pipe 62 is partially disposed in the radiator 12 of the second variable frequency drive module 15. The condenser pipe 80 is partially disposed in the radiators 12 of both the first and second variable frequency drive modules 14 (i.e., condenser pipes 80 are disposed in the radiators 12 of both the first and second variable frequency drive modules 14). Of course, in other embodiments, the two main oil return pipes 60 and the two variable frequency drive modules 10 can be arranged crosswise; that is, the first main oil return pipe 61 is partially disposed in the radiator 12 of the second variable frequency drive module 15, and the second main oil return pipe 62 is partially disposed in the radiator 12 of the first variable frequency drive module 14 (e.g.,...). Figure 1 As shown in the diagram, when the air conditioning system is operating at low load and only one compressor needs to be running, simply activating the oil return circuit of one compressor is sufficient to control the temperature of the inverter drive module 10 corresponding to the stopped compressor, preventing condensation from forming on the inverter drive module 10 and achieving anti-condensation control for the inverter drive module 10 corresponding to the stopped compressor. For example, when the second compressor 22 stops, simply activating the oil return circuit of the first compressor 21 is sufficient to control the temperature of the second inverter drive module 15 and prevent condensation from forming on the second inverter drive module 15; similarly, when the first compressor 21 stops, simply activating the oil return circuit of the second compressor 22 is sufficient to control the temperature of the first inverter drive module 14 and prevent condensation from forming on the first inverter drive module 14.

[0059] Example 2

[0060] Embodiment 2 of this application provides a control method for an air conditioning system, applied to the air conditioning system described in Embodiment 1. The air conditioning system is a single-compressor system, meaning the air conditioning system includes one compressor. A main oil return valve is installed on the main oil return pipe 60 of the air conditioning system, and an auxiliary oil return valve 71 is installed on the auxiliary oil return pipe 70 of the air conditioning system; as... Figure 4As shown, the control method of the air conditioning system includes the following steps: S101, obtaining the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser 80 and the temperature TS of the frequency converter drive module 10; S102, controlling the opening degree of the main oil return valve and the auxiliary oil return valve 71 according to TH, TL and TS.

[0061] Optionally, controlling the opening degree of the main return valve and auxiliary return valve 71 according to TH, TL, and TS includes:

[0062] When TH≥T1 and TS>(TL+T2), the main oil return valve is closed and the auxiliary oil return valve 71 is opened to the maximum opening degree Fmax. Here, T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2. At this time, the air conditioning system only returns oil through the auxiliary oil return pipe 70 valve to ensure the amount of oil returned by the compressor.

[0063] When TH < T1 and TS > (TL + T2), it indicates that the condenser tube 80 cannot effectively cool the temperature of the frequency converter drive module 10. It is necessary to reduce the opening of each return oil valve and control both the main return oil valve and the auxiliary return oil valve 71 to open. The opening of the main return oil valve is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening of the auxiliary return oil valve 71 is F3 = F * K2. Where Fq is the current opening of the main return oil valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0064] When TH < T1 and (TL + T3) < TS < (TL + T2), both the main return valve and the auxiliary return valve 71 are opened. The opening degree of the main return valve is F = Fq + Fb, Fb = (TS - TL) * K3, and the opening degree of the auxiliary return valve 71 is F3 = F * K4. Where T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1.

[0065] When TH < T1 and TS < (TL + T3), the air conditioning system enters anti-condensation control, controls the main oil return valve to open to the maximum opening degree Fmax, controls the auxiliary oil return valve 71 to open, and the opening degree of the auxiliary oil return valve 71 is F3 = Fmax * K5, where K5 is the fifth proportional coefficient, K5 < K4.

[0066] When TH < T1 and TS > (TL + T4), the air conditioning system exits the anti-condensation control, and the opening of the main oil return valve and the auxiliary oil return valve 71 returns to the control of the corresponding temperature range mentioned above. Here, T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

[0067] Optionally, the specific values ​​of T1, T2, T3, T4, K1, K2, K3, K4, and K5 can be set according to actual conditions. The initial opening F0 and maximum opening Fmax of each return valve can be set according to the actual type of return valve. It is important to note that during control, if the calculated target opening F of the return valve exceeds its opening range, the actual opening of the return valve will be adjusted to the one closest to the target opening between the maximum and minimum opening. For example, assuming the main return valve's opening range is 0~480Pls, when the calculated target opening F of the main return valve is less than 0, the actual opening of the main return valve will be adjusted to 0Pls (minimum opening), i.e., the main return valve will be closed; when the calculated target opening F1 of the main return valve is greater than 480Pls, the actual opening of the main return valve will be adjusted to 480Pls (maximum opening).

[0068] In some embodiments of this application, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, F0=250Pls, Fmax=480Pls (i.e., the opening range of the return valve is 0~480Pls), then controlling the opening of the main return valve and the auxiliary return valve 71 according to TH, TL and TS includes:

[0069] When TH≥20℃ and TS>(TL+45℃), the main return valve is closed and the auxiliary return valve 71 is opened to the maximum opening degree of 480Pls.

[0070] When TH < 20℃ and TS > (TL + 45℃), both the main return valve and the auxiliary return valve 71 are opened. The opening degree of the main return valve is F = Fq - Fb, Fb = (TS - TL) * 100, and the opening degree of the auxiliary return valve 71 is F3 = F * 1.5.

[0071] When TH < 20℃ and (TL+5℃) < TS < (TL+45℃), both the main return valve and the auxiliary return valve 71 are opened. The opening degree of the main return valve is F = Fq - Fb, Fb = (TS - TL) * 50, and the opening degree of the auxiliary return valve 71 is F3 = F * 0.6.

[0072] When TH < 20℃ and TS < (TL + 5℃), control the main return valve to open to the maximum opening degree of 480 Pls, control the auxiliary return valve 71 to open, and the opening degree of the auxiliary return valve 71 is F3 = 480Pls * 0.4.

[0073] When TH < 20℃ and TS > (TL + 10℃), the opening degree of the main return oil valve and the auxiliary return oil valve 71 returns to the control of the corresponding temperature range mentioned above.

[0074] Example 3

[0075] Embodiment 3 of this application provides a control method for an air conditioning system, applied to the air conditioning system described in Embodiment 1. The air conditioning system is a dual-compressor system. The compressors in the air conditioning system include a first compressor 21 and a second compressor 22. The variable frequency drive module 10 includes a first variable frequency drive module 14 communicatively connected to the first compressor 21 and a second variable frequency drive module 15 communicatively connected to the second compressor 22. The main oil return pipe 60 includes a first main oil return pipe 61 connected to the first compressor 21 and a second main oil return pipe 62 connected to the second compressor 22. A first main oil return valve 63 is provided on the first main oil return pipe 61, a second main oil return valve 64 is provided on the second main oil return pipe 62, and an auxiliary oil return valve 71 is provided on the auxiliary oil return pipe 70.

[0076] like Figure 5 As shown, the control method of the air conditioning system provided in this embodiment 3 includes the following steps: S201, acquiring the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe 80, the temperature TS1 of the first frequency converter drive module 14, and the temperature TS2 of the second frequency converter drive module 15; S202, controlling the opening degree of the first main oil return valve 63, the second main oil return valve 64, and the auxiliary oil return valve 71 according to TH, TL, TS1, and TS2.

[0077] Optionally, controlling the opening degrees of the first main return valve 63, the second main return valve 64, and the auxiliary return valve 71 according to TH, TL, TS1, and TS2 includes:

[0078] When TH≥T1 and max(TS1,TS2)>(TL+T2), the first main oil return valve 63 and the second main oil return valve 64 are closed, and the auxiliary oil return valve 71 is opened to the maximum opening degree Fmax. Here, T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2. At this time, the air conditioning system only returns oil through the auxiliary oil return pipe 70 valve to ensure the amount of oil returned by the compressor.

[0079] When TH < T1 and max(TS1, TS2) > (TL + T2), it indicates that the condenser tube 80 cannot effectively cool the temperature of the frequency converter drive module 10. It is necessary to reduce the opening of each return oil valve and control the first main return oil valve 63, the second main return oil valve 64 and the auxiliary return oil valve 71 to open. The opening of the first main return oil valve 63 is F1 = Fq1 - Fb1, Fb1 = (TS1 - TL) * K1, the opening of the second main return oil valve 64 is F2 = Fq2 - Fb2, Fb2 = (TS2 - TL) * K1, and the opening of the auxiliary return oil valve 71 is F3 = min(F1, F2) * K2. Here, "max(TS1, TS2)" refers to the larger of TS1 and TS2, Fq1 is the current opening of the first main return oil valve 63, Fq2 is the current opening of the second main return oil valve 64, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0080] When TH < T1, and max (TS1, TS2) < (TL + T2) and min (TS1, TS2) > (TL + T3), the first main return valve 63, the second main return valve 64, and the auxiliary return valve 71 are all opened. The opening degree of the first main return valve 63 is F1 = Fq1 + Fb1, Fb1 = (TS1 - TL) * K3, the opening degree of the second main return valve 64 is F2 = Fq2 + Fb2, Fb2 = (TS2 - TL) * K3, and the opening degree of the auxiliary return valve 71 is F3 = min(F1, F2) * K4. Here, min(TS1, TS2) refers to the smaller of TS1 and TS2, T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, K4 < K2 < K3 < K1.

[0081] When TH < T1 and min (TS1, TS2) < (TL + T3), the air conditioning system enters anti-condensation control. The main oil return valve on the main oil return pipe corresponding to the smaller of TS1 and TS2 is opened to its maximum opening degree Fmax. The auxiliary oil return valve 71 is also opened, with the opening degree F3 = Fmax * K5, where K5 is the fifth proportional coefficient, and K5 < K4. It should be understood that when the first main oil return pipe 63 and the second main oil return pipe 64 are respectively installed on the radiator of the first variable frequency drive module 14 and the radiator of the second variable frequency drive module 15, the first main oil return pipe 63 corresponds to TS1, and the second main oil return pipe 64 corresponds to TS2. When the first main oil return pipe 63 and the second main oil return pipe 64 are respectively installed on the radiator of the second variable frequency drive module 15 and the radiator of the first variable frequency drive module 14 (i.e., cross-installed), the first main oil return pipe 63 corresponds to TS2, and the second main oil return pipe 64 corresponds to TS1.

[0082] When TH < T1 and min (TS1, TS2) > (TL + T4), the air conditioning system exits the anti-condensation control, and the opening of the first main oil return valve 63, the second main oil return valve 64 and the auxiliary oil return valve 71 resumes the control of the corresponding temperature ranges mentioned above. Here, T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

[0083] Optionally, the specific values ​​of T1, T2, T3, T4, K1, K2, K3, K4, and K5 can be set according to actual conditions. The initial opening F0 and maximum opening Fmax of each return valve can be set according to the actual type of return valve. It is important to note that during control, if the calculated target opening of the return valve exceeds its opening range, the actual opening of the return valve will be adjusted to the one closest to the target opening between the maximum and minimum opening. For example, assuming the opening range of the first main return valve 63 is 0~480Pls, when the calculated target opening F1 of the first main return valve 63 is less than 0, the actual opening of the first main return valve 63 will be adjusted to 0Pls (minimum opening), i.e., the first main return valve 63 will be closed; when the calculated target opening F1 of the first main return valve 63 is greater than 480Pls, the actual opening of the first main return valve 63 will be adjusted to 480Pls (maximum opening).

[0084] In some embodiments of this application, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, F0=250Pls, Fmax=480Pls (i.e., the opening range of the return valve is 0~480Pls), then controlling the opening of the first main return valve 63, the second main return valve 64, and the auxiliary return valve 71 according to TH, TL, TS1, and TS2 includes:

[0085] When T-ring ≥ 20℃ and max(TS1, TS2) > (TL + 45℃), control the first main return valve 63 and the second main return valve 64 to close, and control the auxiliary return valve 71 to open to the maximum opening degree 480Pls.

[0086] When T_ring < 20℃ and max(TS1, TS2) > (TL + 45℃), the first main return valve 63, the second main return valve 64, and the auxiliary return valve 71 are all opened. The opening degree of the first main return valve 63 is F1 = Fq1 - Fb1, Fb1 = (TS1 - TL) * 100, the opening degree of the second main return valve 64 is F2 = Fq2 - Fb2, Fb2 = (TS2 - TL) * 100, and the opening degree of the auxiliary return valve 71 is F3 = min(F1, F2) * 1.5.

[0087] When T_ring < 20℃, and max (TS1, TS2) < (TL + 45℃) and min (TS1, TS2) > (TL + 5℃), the first main return valve 63, the second main return valve 64, and the auxiliary return valve 71 are all opened. The opening degree of the first main return valve 63 is F1 = Fq1 + Fb1, Fb1 = (TS1 - TL) * 50, the opening degree of the second main return valve 64 is F2 = Fq2 + Fb2, Fb2 = (TS2 - TL) * 50, and the opening degree of the auxiliary return valve 71 is F3 = min(F1, F2) * 0.6.

[0088] When T ring < 20℃ and min (TS1, TS2) < (TL + 5℃), the main return valve on the main return pipe corresponding to the smaller of TS1 and TS2 is opened to the maximum opening degree of 480Pls, and the auxiliary return valve 71 is opened. The opening degree of the auxiliary return valve 71 is F3 = 480Pls * 0.4.

[0089] When T_ring < 20℃ and min (TS1, TS2) > (TL + 10℃), the opening of the first main return valve 63, the second main return valve 64 and the auxiliary return valve 71 shall be restored to the control of the corresponding temperature range mentioned above.

[0090] Example 4

[0091] Embodiment 4 of this application provides a control method for an air conditioning system, applied to the aforementioned air conditioning system. The air conditioning system is a dual-compressor system. The compressors in the air conditioning system include a first compressor 21 and a second compressor 22. The variable frequency drive module 10 includes a first variable frequency drive module 14 communicatively connected to the first compressor 21 and a second variable frequency drive module 15 communicatively connected to the second compressor 22. The main oil return pipe 60 includes a first main oil return pipe 61 connected to the first compressor 21 and a second main oil return pipe 62 connected to the second compressor 22. The first main oil return pipe 61 is disposed on the second variable frequency drive module 15, and the second main oil return pipe 62 is disposed on the first variable frequency drive module 14 (i.e., the two main oil return pipes are cross-distributed with the two variable frequency modules). A first main oil return valve 63 is disposed on the first main oil return pipe 61, a second main oil return valve 64 is disposed on the second main oil return pipe 62, and an auxiliary oil return valve 71 is disposed on the auxiliary oil return pipe 70.

[0092] like Figure 6As shown, the control method of the air conditioning system provided in this embodiment 4 includes the following steps: S301, controlling the first compressor 21 and the second compressor 22 to not operate simultaneously; S302, acquiring the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe 80, and the temperature TS of the variable frequency drive module 10 corresponding to the operating compressor, wherein the operating compressor refers to one of the first compressor 21 and the second compressor 22, the first compressor 21 corresponds to the second variable frequency drive module 15, and the second compressor 22 corresponds to the first variable frequency drive module 14; S303, controlling the opening degree of the main oil return valve and the auxiliary oil return valve 71 corresponding to the operating compressor according to TH, TL, and TS, wherein the first compressor 21 corresponds to the first main oil return pipe 63, and the second compressor 22 corresponds to the second main oil return pipe 64.

[0093] Optionally, the opening degrees of the main return oil valve and auxiliary return oil valve 71 on the main return oil pipe corresponding to the compressor controlled by TH, TL, and TS include:

[0094] When TH≥T1 and TS>(TL+T2), the main return oil valve on the main return oil pipe corresponding to the compressor is closed, and the auxiliary return oil valve 71 is opened to the maximum opening degree Fmax. Here, T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2.

[0095] When TH < T1 and TS > (TL + T2), both the main return oil valve and the auxiliary return oil valve 71 on the main return oil pipe corresponding to the running compressor are open. The opening degree of the main return oil valve on the main return oil pipe corresponding to the running compressor is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening degree of the auxiliary return oil valve 71 is F3 = F * K2. Where Fq is the current opening degree of the main return oil valve corresponding to the running compressor, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1.

[0096] When TH < T1 and (TL+T3) < TS < (TL+T2), both the main return oil valve and the auxiliary return oil valve 71 on the main return oil pipe corresponding to the compressor are open. The opening degree of the main return oil valve is F = Fq + Fb, Fb = (TS-TL)*K3, and the opening degree of the auxiliary return oil valve 71 is F3 = F*K4. Where T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1.

[0097] When TH < T1 and TS < (TL + T3), the air conditioning system enters anti-condensation control. The main oil return valve on the main oil return pipe corresponding to the running compressor is opened to its maximum opening Fmax, and the auxiliary oil return valve 71 is closed to ensure the temperature of the inverter drive module corresponding to the running compressor and prevent condensation due to low temperature. If TS < (TL + T3) persists for a preset time t, the first compressor 21 and the second compressor 22 are controlled to run alternately. The opening of the main oil return valve and the auxiliary oil return valve 71 on the main oil return pipe corresponding to the running compressor is controlled according to the corresponding temperature range mentioned above, and the main oil return valve on the main oil return pipe corresponding to the non-running compressor is closed. It should be understood that when TS < (TL + T3) persists for a preset time t, it indicates that the oil in the main oil return pipe of the inverter drive module corresponding to the running compressor can no longer effectively raise the temperature of the inverter drive module. At this time, the compressor connected to the inverter drive module needs to be started to allow the temperature TS of the inverter drive module to rise to a suitable temperature.

[0098] During the alternating operation of the first compressor 21 and the second compressor 22, when TH < T1 and TS > (TL + T4), the air conditioning system exits the anti-condensation control, stops the alternating operation of the first compressor 21 and the second compressor 22, and controls the operation of the first compressor 21 and / or the second compressor 22 according to the capacity requirements of the air conditioning system, where T4 is the fourth preset temperature, and T3 < T4 < T1 < T2. Specifically, when both the first compressor 21 and the second compressor 22 are running, the control method of the air conditioning system can adopt the control method described in Example 3.

[0099] Optionally, the specific values ​​of T1, T2, T3, T4, K1, K2, K3, K4, K5, and t can be set according to actual conditions. The initial opening F0 and maximum opening Fmax of each return valve can be set according to the actual type of return valve. It is important to note that during control, if the calculated target opening F of the return valve exceeds its opening range, the actual opening of the return valve will be adjusted to the one closest to the target opening between the maximum and minimum opening. For example, assuming the opening range of the main return valve corresponding to the operating compressor is 0~480Pls, when the calculated target opening F of the main return valve is less than 0, the actual opening of the main return valve will be adjusted to 0Pls (minimum opening), i.e., the main return valve will be closed; when the calculated target opening F of the main return valve is greater than 480Pls, the actual opening of the main return valve will be adjusted to 480Pls (maximum opening).

[0100] In some embodiments of this application, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, F0=250Pls, Fmax=480Pls (i.e., the opening range of the return oil valve is 0~480Pls), t=30min, then the opening of the main return oil valve and auxiliary return oil valve 71 on the main return oil pipe corresponding to the compressor controlled by TH, TL and TS includes:

[0101] When T_ring ≥ 20℃ and T_s > (TL + 45℃), the main oil return valve on the main oil return pipe corresponding to the compressor is closed, and the auxiliary oil return valve 71 is opened to the maximum opening degree of 480Pls.

[0102] When T_ring < 20℃ and T_s > (TL + 45℃), both the main oil return valve and the auxiliary oil return valve 71 on the main oil return pipe corresponding to the compressor are open. The opening degree of the main oil return valve on the main oil return pipe corresponding to the compressor is F = Fq - Fb, Fb = (TS - TL) * 100, and the opening degree of the auxiliary oil return valve 71 is F3 = F * 1.5.

[0103] When T_ring < 20℃ and (TL+5℃) < TS < (TL+45℃), both the main return oil valve and the auxiliary return oil valve 71 on the main return oil pipe corresponding to the compressor are open. The opening degree of the main return oil valve is F = Fq + Fb, Fb = (Ts-TL) * 50, and the opening degree of the auxiliary return oil valve 71 is F3 = F * 0.6.

[0104] When Tring < 20℃ and Ts < (TL + 5℃), the air conditioning system enters anti-condensation control, controls the main oil return valve on the main oil return pipe corresponding to the running compressor to open to 480P1s, and controls the auxiliary oil return valve 71 to close. If TS < (TL + T3) lasts for a preset time of 30 minutes, the first compressor 21 and the second compressor 22 are controlled to run alternately. The opening degree of the main oil return valve and the auxiliary oil return valve 71 on the main oil return pipe corresponding to the running compressor is controlled according to the above-mentioned corresponding temperature range, and the main oil return valve on the main oil return pipe corresponding to the non-running compressor is controlled to close.

[0105] During the alternating operation of the first compressor 21 and the second compressor 22, when T_ring < 20°C and T_s > (TL + 10°C), the air conditioning system exits the anti-condensation control, controls the first compressor 21 and the second compressor 22 to stop alternating operation, and controls the operation of the first compressor 21 and / or the second compressor 22 according to the capacity requirements of the air conditioning system.

[0106] For example, when the first compressor 21 is running and the second compressor 22 is stopped, and T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, F0=250Pls, Fmax=480Pls, and t=30min, the opening degree of the main return oil valve and auxiliary return oil valve 71 on the main return oil pipe corresponding to the running compressor is controlled according to TH, TL, and TS, including:

[0107] When T_ring ≥ 20℃ and TS2 > (TL + 45℃), the first main oil return valve 63 on the first main oil return pipe 61 corresponding to the first compressor 21 is closed, and the auxiliary oil return valve 71 is opened to the maximum opening degree of 480Pls.

[0108] When T_ring < 20℃ and TS2 > (TL + 45℃), the first main oil return valve 63 and the auxiliary oil return valve 71 corresponding to the first compressor 21 are both opened. The opening degree of the first main oil return valve 63 is F1 = Fq1 - Fb1, Fb1 = (TS - TL) * 100, and the opening degree of the auxiliary oil return valve 71 is F3 = F1 * 1.5, where Fq1 is the current opening degree of the first main oil return valve 63.

[0109] When T_ring < 20℃ and (TL+5℃) < TS2 < (TL+45℃), the first main oil return valve 63 and the auxiliary oil return valve 71 corresponding to the first compressor 21 are both opened. The opening degree of the first main oil return valve 63 is F1 = Fq1 + Fb1, Fb1 = (TS-TL) * 50, and the opening degree of the auxiliary oil return valve 71 is F3 = F1 * 0.6.

[0110] When Tring < 20℃ and TS2 < (TL + 5℃), the air conditioning system enters anti-condensation control, controls the first main oil return valve 63 corresponding to the first compressor 21 to open to the maximum opening degree of 480Pls, and controls the auxiliary oil return valve 71 to close. If TS2 < (TL + T3) lasts for a preset time of 30 minutes, the first compressor 21 is controlled to stop, and the second compressor 22 is controlled to run. The opening degree of the second main oil return valve 64 and the auxiliary oil return valve 71 corresponding to the second compressor 22 is controlled according to the above-mentioned corresponding temperature range, and the first main oil return valve 63 corresponding to the first compressor 21 is controlled to close. The first compressor 21 and the second compressor 22 run alternately.

[0111] During the alternating operation of the first compressor 21 and the second compressor 22, when T_ring < 20°C and TS > (TL + 10°C), the air conditioning system exits the anti-condensation control, controls the first compressor 21 and the second compressor 22 to stop alternating operation, and controls the operation of the first compressor 21 and / or the second compressor 22 according to the capacity requirements of the air conditioning system.

[0112] In summary, the air conditioning system control method provided in embodiments 2-4 of this application determines the heat dissipation effect and condensation risk of the variable frequency drive module 10 based on the outdoor ambient temperature TH, the refrigerant temperature TL in the condenser pipe 80, and the temperature TS of the variable frequency drive module 10. By controlling the opening of each oil return valve (i.e., the main oil return valve and the auxiliary oil return valve 71), the temperature of the variable frequency drive module 10 and the amount of oil returned by the compressor are controlled to meet the requirements, so that the temperature of the variable frequency drive module 10 is kept in a suitable temperature range to prevent condensation. At the same time, the temperature in the main oil return pipe 60 is cooled, which increases the compressor's suction volume and improves the energy efficiency of the air conditioning system, avoiding affecting user comfort and increasing the energy consumption of air conditioning operation.

[0113] Compared with the prior art, the technical solution provided in this application has at least the following beneficial effects:

[0114] (1) Comparison of anti-condensation schemes: When the existing air conditioning system detects a risk of condensation in the inverter drive module 10, there are generally two control schemes. One scheme is to increase the opening of the air conditioning heating electronic expansion valve and the energy efficiency ratio opening of the air conditioning indoor unit. By increasing the valve opening, the throttling effect is reduced, and the refrigerant temperature in the condenser 80 is increased. However, this will affect the user's comfort. When the air conditioning system with two compressors is running at low load, only one compressor needs to be turned on. The inverter drive module 10 corresponding to the shut-off compressor will easily generate condensation. The other scheme is to control the shutdown... Low-frequency operation of the compressor leads to increased energy consumption in the air conditioning system and reduced compressor reliability. The application addresses this by controlling the opening of each oil return valve (i.e., the main oil return valve and the auxiliary oil return valve 71) to control the temperature of the variable frequency drive module 10 and the amount of oil returned by the compressor to meet the requirements. This ensures that the temperature of the variable frequency drive module 10 is always within a suitable temperature range, preventing condensation in the variable frequency drive module 10. At the same time, the temperature in the main oil return pipe 60 is cooled, increasing the compressor's suction volume and improving the energy efficiency of the air conditioning system. This avoids affecting user comfort and increasing the energy consumption of the air conditioning system.

[0115] (2) Comparison of oil return schemes: The existing air conditioning system returns oil directly to the suction side of the compressor from the oil-gas separator 31, which causes the suction temperature of the compressor to overheat, thereby reducing the suction volume of the compressor and thus reducing the cooling capacity. In contrast, this application uses the radiator 12 to ensure the heat dissipation of the variable frequency drive module 10, and makes full use of the oil in the main oil return pipe 60 to exchange heat with the refrigerant in the condenser pipe 80 to reduce the oil return temperature. At the same time, an auxiliary oil return pipe 70 is added to supplement the compressor oil return during the temperature adjustment process of the variable frequency drive module 10, so as to avoid the oil return not meeting the compressor requirements due to the reduction of the opening of the main oil return valve.

[0116] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0117] In the description of this application, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more features.

[0118] The air conditioning system and its control method provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An air conditioning system, characterized in that, The system includes a variable frequency drive module (10), a compressor, an oil-gas separator (31), a gas-liquid separator (32), a four-way valve (40), an outdoor heat exchanger (51), and an indoor heat exchanger (52). The variable frequency drive module (10) includes an electronic control board (11) and a radiator (12) mounted on the electronic control board (11). The variable frequency drive module (10) is communicatively connected to the compressor. The compressor outlet is connected to the refrigerant inlet of the oil-gas separator (31), the oil outlet of the oil-gas separator (31) is connected to the compressor inlet via the main oil return pipe (60), the oil outlet of the oil-gas separator (31) is connected to the inlet of the gas-liquid separator (32) via the auxiliary oil return pipe (70), and the four-way valve (40) is connected to the refrigerant outlet of the oil-gas separator (31), the inlet of the gas-liquid separator (32), the refrigerant inlet of the outdoor heat exchanger (51), and the refrigerant outlet of the indoor heat exchanger (52) respectively. The refrigerant outlet of the outdoor heat exchanger (51) is connected to the refrigerant inlet of the indoor heat exchanger (52) via a condenser pipe (80). Both the condenser pipe (80) and the main oil return pipe (60) are partially located in the radiator (12).

2. The air conditioning system according to claim 1, characterized in that, The portion of the condenser tube (80) located in the radiator (12) is parallel to the portion of the main oil return pipe (60) located in the radiator (12), and the refrigerant flow direction in the condenser tube (80) is the same as or opposite to the oil flow direction in the main oil return pipe (60).

3. The air conditioning system according to claim 2, characterized in that, The portion of the condenser pipe (80) located in the radiator (12) and the portion of the main oil return pipe (60) located in the radiator (12) are both U-shaped, and the U-shaped portion of the condenser pipe (80) is located inside the U-shaped portion of the main oil return pipe (60).

4. The air conditioning system according to claim 1, characterized in that, A main return valve is provided on the main return pipe (60), and an auxiliary return valve (71) is provided on the auxiliary return pipe (70). The air conditioning system also includes a controller, an outdoor temperature sensor (91) for detecting the outdoor ambient temperature, a module temperature sensor for detecting the temperature of the variable frequency drive module (10), and a refrigerant temperature sensor (92) for detecting the refrigerant temperature in the condenser (80). The outdoor temperature sensor (91), the module temperature sensor, the refrigerant temperature sensor (92), the main oil return valve, and the auxiliary oil return valve (71) are all communicatively connected to the controller.

5. The air conditioning system according to claim 1, characterized in that, The radiator (12) includes a heat sink (121) and heat sink fins (122). The heat sink (121) is disposed on the electronic control board (11), and the heat sink fins (122) are disposed on the heat sink (121). The condenser pipe (80) and the main oil return pipe (60) are both partially disposed in the heat sink (121).

6. The air conditioning system according to any one of claims 1 to 5, characterized in that, The variable frequency drive module (10) includes a first variable frequency drive module (14) and a second variable frequency drive module (15), and the compressor includes a first compressor (21) and a second compressor (22). The first compressor (21) is communicatively connected to the first variable frequency drive module (14), and the second compressor (22) is communicatively connected to the second variable frequency drive module (15). The main return oil pipe (60) includes a first main return oil pipe (61) and a second main return oil pipe (62). The oil outlet of the oil-gas separator (31) is connected to the air inlet of the first compressor (21) through the first main return oil pipe (61), and the oil outlet of the oil-gas separator (31) is connected to the air inlet of the second compressor (22) through the second main return oil pipe (62). The first main return oil pipe (61) is partially disposed in the radiator (12) of the first variable frequency drive module (14), the second main return oil pipe (62) is partially disposed in the radiator (12) of the second variable frequency drive module (15), and the condenser pipe (80) is partially disposed in the radiators (12) of both the first variable frequency drive module (14) and the second variable frequency drive module (15).

7. The air conditioning system according to any one of claims 1 to 5, characterized in that, The variable frequency drive module (10) includes a first variable frequency drive module (14) and a second variable frequency drive module (15), and the compressor includes a first compressor (21) and a second compressor (22). The first compressor (21) is communicatively connected to the first variable frequency drive module (14), and the second compressor (22) is communicatively connected to the second variable frequency drive module (15). The main return oil pipe (60) includes a first main return oil pipe (61) and a second main return oil pipe (62). The oil outlet of the oil-gas separator (31) is connected to the air inlet of the first compressor (21) through the first main return oil pipe (61), and the oil outlet of the oil-gas separator (31) is connected to the air inlet of the second compressor (22) through the second main return oil pipe (62). The first main return oil pipe (61) is partially disposed in the radiator (12) of the second variable frequency drive module (15), the second main return oil pipe (62) is partially disposed in the radiator (12) of the first variable frequency drive module (14), and the condenser pipe (80) is partially disposed in the radiators (12) of both the first variable frequency drive module (14) and the second variable frequency drive module (15).

8. A control method for an air conditioning system, characterized in that, Applied to an air conditioning system as described in any one of claims 1 to 7, the main return oil pipe (60) of the air conditioning system is provided with a main return oil valve, and the auxiliary return oil pipe (70) of the air conditioning system is provided with an auxiliary return oil valve (71); the control method includes the following steps: The outdoor ambient temperature TH, the refrigerant temperature TL inside the condenser tube (80) and the temperature TS of the frequency converter drive module (10) are obtained. The opening degree of the main return valve and the auxiliary return valve (71) is controlled according to TH, TL and TS.

9. The control method according to claim 8, characterized in that, The control of the opening degree of the main return valve and the auxiliary return valve (71) according to TH, TL and TS includes: When TH≥T1 and TS>(TL+T2), the main return valve is closed and the auxiliary return valve (71) is opened to the maximum opening degree Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2; When TH < T1 and TS > (TL + T2), the main return valve and the auxiliary return valve (71) are both opened. The opening degree of the main return valve is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening degree of the auxiliary return valve (71) is F3 = F * K2. Wherein, Fq is the current opening degree of the main return valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1. When TH < T1 and (TL + T3) < TS < (TL + T2), the main return valve and the auxiliary return valve (71) are both opened. The opening degree of the main return valve is F = Fq + Fb, Fb = (TS - TL) * K3, and the opening degree of the auxiliary return valve (71) is F3 = F * K4. Where T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1. When TH < T1 and TS < (TL + T3), the main return valve is controlled to open to the maximum opening Fmax, and the auxiliary return valve (71) is controlled to open. The opening of the auxiliary return valve (71) is F3 = Fmax * K5, where K5 is the fifth proportional coefficient and K5 < K4. When TH < T1 and TS > (TL + T4), the opening degree of the main return oil valve and the auxiliary return oil valve (71) is restored to the above-mentioned corresponding temperature range control, where T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

10. The control method according to claim 9, characterized in that, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.

4.

11. A control method for an air conditioning system, characterized in that, Applied to an air conditioning system as described in any one of claims 1 to 7, the compressor in the air conditioning system includes a first compressor (21) and a second compressor (22), the variable frequency drive module (10) includes a first variable frequency drive module (14) communicatively connected to the first compressor (21) and a second variable frequency drive module (15) communicatively connected to the second compressor (22), the main oil return pipe (60) includes a first main oil return pipe (61) connected to the first compressor (21) and a second main oil return pipe (62) connected to the second compressor (22), a first main oil return valve (63) is provided on the first main oil return pipe (61), a second main oil return valve (64) is provided on the second main oil return pipe (62), and an auxiliary oil return valve (71) is provided on the auxiliary oil return pipe (70). The control method includes the following steps: The outdoor ambient temperature TH, the refrigerant temperature TL inside the condenser (80), the temperature TS1 of the first frequency converter drive module (14), and the temperature TS2 of the second frequency converter drive module (15) are obtained. The opening degrees of the first main return valve (63), the second main return valve (64), and the auxiliary return valve (71) are controlled according to TH, TL, TS1, and TS2.

12. The control method according to claim 11, characterized in that, The control of the opening degrees of the first main return valve (63), the second main return valve (64), and the auxiliary return valve (71) based on TH, TL, TS1, and TS2 includes: When TH≥T1 and max(TS1,TS2)>(TL+T2), the first main return valve (63) and the second main return valve (64) are closed, and the auxiliary return valve (71) is opened to the maximum opening degree Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2. When TH < T1 and max(TS1, TS2) > (TL + T2), the first main return valve (63), the second main return valve (64), and the auxiliary return valve (71) are all opened. The opening degree of the first main return valve (63) is F1 = Fq1 - Fb1, Fb1 = (TS1 - TL) * K1, the opening degree of the second main return valve (64) is F2 = Fq2 - Fb2, Fb2 = (TS2 - TL) * K1, and the opening degree of the auxiliary return valve (71) is F3 = min(F1, F2) * K2. Wherein, Fq1 is the current opening degree of the first main return valve (63), Fq2 is the current opening degree of the second main return valve (64), K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1. When TH < T1, and max (TS1, TS2) < (TL+T2) and min (TS1, TS2) > (TL+T3), the first main return valve (63), the second main return valve (64), and the auxiliary return valve (71) are all opened. The opening degree of the first main return valve (63) is F1 = Fq1 + Fb1, Fb1 = (TS1 - TL) * K3, the opening degree of the second main return valve (64) is F2 = Fq2 + Fb2, Fb2 = (TS2 - TL) * K3, and the opening degree of the auxiliary return valve (71) is F3 = min(F1, F2) * K4. Wherein, T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, K4 < K2 < K3 < K1; When TH < T1 and min (TS1, TS2) < (TL + T3), the main return valve on the main return pipe corresponding to the smaller of TS1 and TS2 is controlled to open to the maximum opening degree Fmax, and the auxiliary return valve (71) is controlled to open. The opening degree of the auxiliary return valve (71) F3 = Fmax * K5, where K5 is the fifth proportional coefficient, K5 < K4; When TH < T1 and min (TS1, TS2) > (TL + T4), the opening degree of the first main return valve (63), the second main return valve (64) and the auxiliary return valve (71) are restored to the above-mentioned corresponding temperature range control, where T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

13. The control method according to claim 12, characterized in that, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.

4.

14. A control method for an air conditioning system, characterized in that, Applied to an air conditioning system as described in any one of claims 1 to 5 and 7, the compressor in the air conditioning system includes a first compressor (21) and a second compressor (22), the variable frequency drive module (10) includes a first variable frequency drive module (14) communicatively connected to the first compressor (21) and a second variable frequency drive module (15) communicatively connected to the second compressor (22), the main oil return pipe (60) includes a first main oil return pipe (61) disposed on the radiator of the second variable frequency drive module (15) and a second main oil return pipe (62) disposed on the radiator of the first variable frequency drive module (14), a first main oil return valve (63) is disposed on the first main oil return pipe (61), a second main oil return valve (64) is disposed on the second main oil return pipe (62), and an auxiliary oil return valve (71) is disposed on the auxiliary oil return pipe (70); The control method includes the following steps: Control the first compressor (21) and the second compressor (22) to not operate simultaneously; The outdoor ambient temperature TH, the refrigerant temperature TL in the condenser (80) and the temperature TS of the variable frequency drive module (10) corresponding to the running compressor are obtained. The running compressor refers to one of the first compressor (21) and the second compressor (22) in operation. The first compressor (21) corresponds to the second variable frequency drive module (15), and the second compressor (22) corresponds to the first variable frequency drive module (14). The opening degree of the main return oil valve and the auxiliary return oil valve (71) on the main return oil pipe corresponding to the operating compressor is controlled according to TH, TL and TS, wherein the first compressor (21) corresponds to the first main return oil pipe (61) and the second compressor (22) corresponds to the second main return oil pipe (62).

15. The control method according to claim 14, characterized in that, The control of the opening degree of the main return oil valve and the auxiliary return oil valve (71) on the main return oil pipe corresponding to the operating compressor according to TH, TL and TS includes: When TH≥T1 and TS>(TL+T2), the main return oil valve on the main return oil pipe corresponding to the running compressor is closed, and the auxiliary return oil valve (71) is opened to the maximum opening degree Fmax, where T1 is the first preset temperature, T2 is the second preset temperature, and T1<T2; When TH < T1 and TS > (TL + T2), the main return oil valve and the auxiliary return oil valve (71) on the main return oil pipe corresponding to the operating compressor are both opened. The opening degree of the main return oil valve is F = Fq - Fb, Fb = (TS - TL) * K1, and the opening degree of the auxiliary return oil valve (71) is F3 = F * K2. Wherein, Fq is the current opening degree of the main return oil valve, K1 is the first proportional coefficient, K2 is the second proportional coefficient, and K2 < K1. When TH < T1 and (TL+T3) < TS < (TL+T2), the main return oil valve and the auxiliary return oil valve (71) on the main return oil pipe corresponding to the operating compressor are both opened. The opening degree of the main return oil valve is F = Fq + Fb, Fb = (TS-TL) * K3, and the opening degree of the auxiliary return oil valve (71) is F3 = F * K4. Wherein, T3 is the third preset temperature, T3 < T1 < T2, K3 is the third proportional coefficient, K4 is the fourth proportional coefficient, and K4 < K2 < K3 < K1. When TH < T1 and TS < (TL + T3), the main return oil valve corresponding to the running compressor is controlled to open to the maximum opening degree Fmax, and the auxiliary return oil valve (71) is controlled to close. If TS < (TL + T3) lasts for a preset time t, the first compressor (21) and the second compressor (22) are controlled to run alternately. The opening degree of the main return oil valve on the main return oil pipe corresponding to the running compressor and the auxiliary return oil valve (71) is controlled according to the above temperature range. The main return oil valve on the main return oil pipe corresponding to the non-running compressor is controlled to close. During the alternating operation of the first compressor (21) and the second compressor (22), when TH < T1 and TS > (TL + T4), the alternating operation of the first compressor (21) and the second compressor (22) is stopped, and the operation of the first compressor (21) and / or the second compressor (22) is controlled according to the capacity requirements of the air conditioning system, wherein T4 is the fourth preset temperature, and T3 < T4 < T1 < T2.

16. The control method according to claim 15, characterized in that, T1=20℃, T2=45℃, T3=5℃, T4=10℃, K1=100, K2=1.5, K3=50, K4=0.6, K5=0.4, t=30min.

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