Cooling system, control method, and air conditioning unit

Abstract

The present invention discloses a cooling system, a control method, and an air conditioning unit. The cooling system includes a main circuit and a cooling branch for cooling heat-generating components. The main circuit has a compressor, a condenser, a flash unit, and an evaporator connected in sequence. One end of the cooling branch is connected to the condenser via a cooling throttle valve. The other end of the cooling branch is provided with a flash unit and an evaporation unit, both of which can be switched on and off. The flash unit is connected to the flash unit, and the evaporation unit is connected to the evaporator. The evaporation unit is equipped with a refrigerant pump. The present invention adds a refrigerant pump to the evaporation unit. When the evaporation unit is connected, the refrigerant is pressurized by the refrigerant pump, increasing the pressure difference between the front and rear ends of the cooling branch, thereby improving cooling capacity and avoiding insufficient cooling.

Description

Technical Field

[0001] The present invention relates to the technical field of cooling systems, and in particular to a cooling system with a condenser and a refrigerant pump jointly supplying liquid, a control method, and an air-conditioning unit. Background Art

[0002] For air-conditioning units, heat-generating components such as motors will generate a large amount of heat as the operating time accumulates and the operating load increases during use. Therefore, an effective cooling solution is needed to ensure the reliability of the motor operation. The current conventional cooling solution is to take high-pressure liquid refrigerant from the condenser, cool it down and reduce its pressure through an electronic expansion valve, and then use the pressure difference between the condensing pressure of the refrigerant in the condenser and the refrigerant in the evaporator to send the liquid refrigerant to the heat-generating components. The refrigerant absorbs heat and evaporates, then enters the evaporator, thereby achieving the purpose of cooling the heat-generating components. However, due to different operating conditions of the unit, the pressure difference between the condenser and the evaporator varies greatly. It is easy for the reduction in the pressure difference to cause a large change in the cooling liquid supply before and after the operating condition is switched, which in turn leads to an oversupply or undersupply of cooling for the heat-generating components, affecting the normal operation of the heat-generating components and the unit.

[0003] Existing solutions address the poor adaptability before and after operating mode switching. These solutions connect cooling branches to the flash unit and evaporator, switching the flow paths and adjusting the throttle valve opening to increase or decrease the cooling flow in the cooling branches, thus preventing over- or under-cooling. However, the throttle valve's ability to regulate refrigerant flow is very limited, making it impossible to effectively guarantee refrigerant supply. During unit operation, insufficient refrigerant flow due to a decrease in pressure differential can still occur.

[0004] Therefore, how to design a cooling system, control method and air-conditioning unit that effectively improves cooling capacity is a technical problem that needs to be solved urgently in the industry. Summary of the Invention

[0005] In order to solve the defects of limited pressure difference adjustment range and insufficient cooling output capacity of existing air-conditioning units, the present invention proposes a cooling system, a control method and an air-conditioning unit. By adding a refrigerant pump to the evaporative flow path, when the evaporative flow path is connected, the refrigerant is pressurized by the refrigerant pump, so that the pressure difference between the front and rear ends of the cooling branch is increased, thereby improving the cooling capacity and avoiding insufficient cooling.

[0006] The technical solution adopted by the present invention is to design a cooling system, including: a main circuit and a cooling branch for cooling heat-generating components, the main circuit has a compressor, a condenser, a flash heater and an evaporator connected in sequence, one end of the cooling branch is connected to the condenser through a cooling throttle valve, and the other end of the cooling branch is provided with a flash flow path and an evaporation flow path that can switch on and off states, the flash flow path is connected to the flash heater, the evaporation flow path is connected to the evaporator, and the evaporation flow path is installed with a refrigerant pump.

[0007] Furthermore, the cooling system also includes: a first detection module for detecting the refrigerant supply volume of the cooling system, the refrigerant pump and the first detection module are both connected to the controller of the cooling system; when the evaporation flow path is connected, the controller turns on the refrigerant pump and controls the working state of the refrigerant pump according to the refrigerant supply volume.

[0008] In some embodiments, the first detection module uses a liquid level sensor or a flow meter. The liquid level sensor is installed in the condenser or the evaporator, and the flow meter is installed in the cooling branch or the main circuit.

[0009] Furthermore, the main circuit is provided with a primary throttle valve and a secondary throttle valve, the primary throttle valve is connected in series between the condenser and the flash evaporator, and the secondary throttle valve is connected in series between the flash evaporator and the evaporator.

[0010] Furthermore, the cooling system also includes: a second detection module for detecting the temperature parameters of the main circuit and the cooling branch, the first-level throttle valve, the second-level throttle valve and the second detection module are all connected to the controller of the cooling system, and the controller synchronously adjusts the opening of the first-level throttle valve and the second-level throttle valve according to the temperature parameters.

[0011] Furthermore, the temperature parameters include: the actual temperature of the heat-generating component, the temperature of the refrigerant before and after the heat-generating component, the evaporation temperature of the evaporator, and the outlet temperature of the chilled water flowing out of the evaporator.

[0012] The present invention also proposes a control method for the above cooling system, comprising the following steps:

[0013] Detect the actual temperature of heating components;

[0014] Switch the on / off status of the flash flow path and the evaporation flow path according to the actual temperature;

[0015] After the evaporation flow path is connected, the working state of the refrigerant pump is controlled according to the refrigerant supply amount of the cooling system.

[0016] Furthermore, controlling the working state of the refrigerant pump according to the refrigerant supply amount includes:

[0017] When the refrigerant supply reaches or exceeds the set supply, the current opening of the refrigerant pump is maintained;

[0018] When the refrigerant supply volume is lower than the set supply volume, increase the opening of the refrigerant pump.

[0019] In some embodiments, the refrigerant supply volume is the actual liquid level of the condenser, and the set supply volume is the set liquid level of the condenser; the opening of the refrigerant pump after enlargement is calculated by the setting function model, and the setting function model is: opening = (actual liquid level × 0.3 × rated flow) / 100.

[0020] Furthermore, switching the on / off states of the flash flow path and the evaporation flow path according to the actual temperature includes:

[0021] When the actual temperature is lower than the set lower limit threshold, the flash flow path is connected and the evaporation flow path is closed;

[0022] When the actual temperature is higher than the set upper limit threshold, the flash flow path is closed and the evaporation flow path is connected.

[0023] Furthermore, the control method further includes: when the actual temperature is within the target temperature range, the opening of the first throttle valve and the opening of the second throttle valve remain unchanged;

[0024] When the actual temperature is outside the target temperature range, the temperature parameters of the main circuit and the cooling branch are detected, and the opening of the first-stage throttle valve and the opening of the second-stage throttle valve are synchronously adjusted according to the temperature parameters.

[0025] In some embodiments, synchronously adjusting the opening of the primary throttle valve and the opening of the secondary throttle valve according to the temperature parameter includes:

[0026] D=D1+D2,D C =U×D;

[0027] When │△Tshdt│≤set deviation, D1=0;

[0028] When │△Tshdt│>set deviation, D1=A_EXV1×Kp_EXV1×△Tshdt+A_EXV1×Ki_EXV1×(△Tshdt-△Tshdt'), △Tshdt=Tshd-Tshdt;

[0029] When Tdwc≥A_EXV1×dwc_EXV1, D2=A_EXV1×Kp1_EXV1×△Tdwct,△Tdwct=Tdwc-A_EXV1×dwc_EXV1;

[0030] When Tdwc<A_EXV1×dwc_EXV1, D2=0;

[0031] Among them, D is the opening adjustment of the first-stage throttle valve, D C is the opening adjustment amount of the secondary throttle valve, U is the proportional coefficient, Tshd is the actual superheat temperature of the heating component, Tshdt is the target superheat temperature of the heating component, △Tshdt is the superheat deviation of the heating component in the current cycle, △Tshdt' is the superheat deviation of the heating component in the previous cycle, A_EXV1 is the correction coefficient, Kp_EXV1 and Kp1_EXV1 are both proportional coefficients, Ki_EXV1 is the integral coefficient, Tdwc is the actual evaporator end temperature difference, dwc_EXV1 is the target evaporator end temperature difference, and △Tdwct is the evaporator end temperature difference deviation.

[0032] The present invention also provides an air-conditioning unit, which adopts the above cooling system.

[0033] In some embodiments, the air conditioning unit is a centrifugal chiller.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. By adding a refrigerant pump to the evaporation flow path, when the evaporation flow path is connected, the refrigerant is pressurized by the refrigerant pump, which increases the pressure difference between the front and rear ends of the cooling branch, thereby ensuring the refrigerant supply, effectively improving the cooling capacity and avoiding insufficient cooling;

[0036] 2. The controller synchronously adjusts the opening of the first-stage throttle valve and the second-stage throttle valve according to the temperature parameters to achieve a reasonable match between the cooling capacity of the cooling system and the heat generation of the heating components, avoid the cooling capacity loss of the cooling system, and improve the operating reliability of the air-conditioning unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which:

[0038] Figure 1 It is a connection diagram of the cooling system of the present invention. DETAILED DESCRIPTION

[0039] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this patent and are not intended to limit this patent.

[0040] like Figure 1As shown, the cooling system proposed in the present invention is applicable to air conditioning units, including but not limited to centrifugal chillers. The cooling system primarily comprises a main circuit and a cooling branch circuit. The main circuit comprises a compressor 5, a condenser 1, a flash unit 8, and an evaporator 13, which are sequentially connected. The cooling branch circuit cools heat-generating components 6. One end of the cooling branch circuit is connected to the condenser 1 via a cooling throttle valve 3, and the other end of the cooling branch circuit is connected to the low-pressure side of the cooling system. In more detail, part of the refrigerant flowing out of the condenser 1 is sent to the cooling branch, and a flash flow path and an evaporation flow path are arranged in parallel at the other end of the cooling branch. The flash flow path is connected to the flash condenser 8, and the air outlet of the flash condenser 8 is connected to the air supply port of the compressor 5 through the intermediate air supply pipe 2. The liquid outlet of the flash condenser 8 is connected to the evaporator 13, and the evaporation flow path is connected to the evaporator 13. The flash flow path is equipped with a flash control valve 7, and the evaporation flow path is equipped with an evaporation control valve 9. The flash control valve 7 and the evaporation control valve 9 can realize the flexible switching of the on and off states of the flow paths in which they are located. The refrigerant flowing out of the cooling branch can be sent to the flash condenser 8 through the flash flow path, or sent to the evaporator 13 through the evaporation flow path.

[0041] Heat-generating components include but are not limited to motors. Taking the motor as an example, the design principle of the cooling system is as follows: Based on the principles of fluid mechanics and related research experience, the mass flow rate of the fluid flowing through a throttle valve is calculated as follows: Among them, C D is the flow coefficient, A is the flow area of ​​the throttle valve, both of which are only related to the geometric structure of the throttle valve; Δp is the pressure difference before and after the throttle valve; ρ1 is the fluid density before the throttle valve.

[0042] According to the above flow formula, ignoring the flow loss of refrigerant inside the motor or evaporator, when the throttle valve is selected (the geometric structure is determined), C D and A are fixed values, Δp is the condensation pressure p c and evaporation pressure p e (cooling branch connected to evaporator) or condensing pressure p c and flash pressure p s (cooling branch connected to the flash ignition source), where ρ1 is the refrigerant liquid density at the front end of the cooling branch, i.e., at the condenser outlet. For identical design operating conditions, the outlet state of condenser 1 remains the same, i.e., ρ1 remains the same. Therefore, under the same other conditions, a greater pressure differential Δp when the cooling branch is connected to evaporator 13 than when it is connected to flash ignition source 8 results in a greater refrigerant flow rate in the cooling branch.

[0043] Under certain operating conditions where the difference between condensing and evaporating pressures is significantly greater, the refrigeration cycle efficiency is poor. To ensure the unit's maximum output capacity, the motor power must be significantly increased, resulting in greater motor heat generation than under normal operating conditions. To ensure cooling reliability, the cooling system must design the throttle valve based on the maximum heat generation. If the cooling line is connected solely to the evaporator 13 or the flash unit 8, the throttle valve's adjustment range is limited to the operating range under high-load conditions. The low-load operating range of the refrigeration condition deviates significantly from the high-load condition. Under these conditions, the motor heat generation is significantly lower, resulting in excess cooling capacity in the cooling system, causing system cooling loss. If the throttle valve is designed based on this, the required cooling capacity under high-load conditions cannot be met, causing the motor to overheat and shorten its service life.

[0044] Based on the above analysis, a flash flow path and an evaporation flow path are designed at the outlet of the cooling branch. The on-off state of the flash flow path and the evaporation flow path is switched according to the heat generated by the heating component to adjust the refrigerant supply volume to adapt to the heating conditions of the heating component. On the basis of the flash flow path and the evaporation flow path, the present invention installs a refrigerant pump in the evaporation flow path. When the temperature of the heating component is high, the evaporation flow path is connected and the refrigerant pump 10 is turned on. After the refrigerant flows out of the condenser 1, it is pressurized by the refrigerant pump 10, which increases the inlet and outlet pressure difference of the cooling branch, thereby ensuring the refrigerant supply volume, effectively improving the cooling capacity, and avoiding insufficient cooling.

[0045] like Figure 1 As shown, in some embodiments, the cooling system further includes a liquid level sensor 11, which is used to detect the actual liquid level of the condenser 1, and the actual liquid level accurately reflects the amount of refrigerant supplied to the cooling system. To achieve automated control of the refrigerant pump, the refrigerant pump 10 and the liquid level sensor 11 are both connected to a controller of the cooling system. When the evaporation flow path is connected, the controller turns on the refrigerant pump 10 and controls the operating state of the refrigerant pump 10 based on the actual liquid level. That is, when the actual liquid level is low, the opening of the refrigerant pump 10 is increased to increase the refrigerant supply.

[0046] It should be understood that the refrigerant supply of the cooling system is detected by the first detection module. The above-mentioned liquid level sensor is only a feasible implementation scheme of the first detection module. The first detection module can also use a flow meter to detect the refrigerant flow rate of the cooling branch through the flow meter to reflect the refrigerant supply amount of the cooling system. Since the refrigerant will circulate in the main circuit and the cooling branch, in actual applications, the liquid level sensor can also detect the liquid level of the evaporator to reflect the refrigerant supply amount of the cooling system. The flow meter detecting the refrigerant flow rate of the main circuit can also reflect the refrigerant supply amount of the cooling system. The present invention does not impose any special restrictions on the specific sensor type and installation position of the first detection module. It is sufficient to be able to reflect the refrigerant supply amount of the cooling system.

[0047] In some embodiments, the main circuit is provided with a primary throttle valve 4 and a secondary throttle valve 12. The primary throttle valve 4 is connected in series between the condenser 1 and the flash generator 8, and the secondary throttle valve 12 is connected in series between the flash generator 8 and the evaporator 13. The cooling flow rate is regulated by the primary throttle valve 4 and the secondary throttle valve 12. To achieve automated control of the primary throttle valve 4 and the secondary throttle valve 12, both the primary throttle valve 4 and the secondary throttle valve 12 are connected to a controller of the cooling system. The cooling system is also provided with a second detection module, which is used to detect temperature parameters of the main circuit and the cooling branch. The controller synchronously adjusts the opening of the primary throttle valve 4 and the secondary throttle valve 12 based on the temperature parameters.

[0048] More precisely, the second detection module includes multiple temperature sensors, which are used to detect the actual temperature of the heating component, the refrigerant temperature before and after passing through the heating component, the evaporation temperature of the evaporator, and the chilled water outlet temperature flowing out of the evaporator. The second detection module collects the refrigerant temperature before and after the cooling branch passes through the heating component. The controller takes the temperature difference between the refrigerant temperatures before and after passing through the heating component 6 to obtain the actual heating component temperature superheat, and uses the actual heating component temperature superheat to calculate part of the adjustment amount of the first-level throttle valve 4. The second detection module also collects the evaporation temperature of the evaporator 13 and the outlet temperature of the chilled water flowing out of the evaporator 13. The controller takes the temperature difference between the outlet temperature of the chilled water and the evaporation temperature to obtain the actual evaporator end temperature difference, and uses the actual evaporator end temperature difference to calculate another part of the adjustment amount of the first-level throttle valve 4. The two parts of the adjustment amount are superimposed to obtain the opening adjustment amount of the first-level throttle valve 4. The opening of the second-level throttle valve 12 is adjusted synchronously with the first-level throttle valve 4. By adjusting the openings of the first-level throttle valve 4 and the second-level throttle valve 12, the output capacity of the cooling system can reasonably match the heat generation of the heat-generating component 6 and the load requirements of the terminal equipment, thereby improving the operating stability of the unit and avoiding insufficient or wasteful cooling.

[0049] Specifically, the control method executed by the controller is as follows:

[0050] Detecting the actual temperature of the heating component 6;

[0051] The on / off states of the flash flow path and the evaporation flow path are switched according to the actual temperature. When the actual temperature is lower than the set lower limit threshold, the flash flow path is connected and the evaporation flow path is closed. When the actual temperature is higher than the set upper limit threshold, the flash flow path is closed and the evaporation flow path is connected.

[0052] After the evaporation flow path is connected, the working state of the refrigerant pump 10 is controlled according to the refrigerant supply amount of the cooling system.

[0053] Specifically, the working state adjustment process of the refrigerant pump 10 is: the refrigerant pump 10 works at the set initial opening when it starts. When the refrigerant supply reaches above the set supply, it means that the refrigerant supply of the cooling system is sufficient, and the controller maintains the current opening of the refrigerant pump 10. When the refrigerant supply is lower than the set supply, it means that the refrigerant supply of the cooling system is insufficient, and the controller increases the opening of the refrigerant pump 10 to increase the inlet and outlet pressure difference of the cooling branch and increase the refrigerant supply.

[0054] In order to achieve precise control of the opening of the refrigerant pump, in some embodiments, the refrigerant supply volume is the actual liquid level of the condenser, and the set supply volume is the set liquid level of the condenser. The inventors have obtained a setting function model suitable for centrifugal chillers through a large number of experimental statistical analyses. The opening of the refrigerant pump after enlargement is calculated through the setting function model. The setting function model is: opening = (actual liquid level × 0.3 × rated flow) / 100, and the rated flow is the rated flow of the refrigerant pump.

[0055] In some embodiments, the control method further includes:

[0056] When the actual temperature is within the target temperature range, it means that the temperature of the heat-generating component is within the appropriate range, the cooling capacity of the cooling system is adequate, and the opening of the first-stage throttle valve and the opening of the second-stage throttle valve remain unchanged;

[0057] When the actual temperature is outside the target temperature range, it means that the temperature of the heat-generating component is too high or too low, the cooling system is insufficiently supplied with cold water or has an excessive supply of cold water. The temperature parameters of the main circuit and the cooling branch are detected, and the opening of the first-stage throttle valve and the opening of the second-stage throttle valve are adjusted synchronously according to the temperature parameters.

[0058] It should be noted that the upper and lower thresholds are designed based on the heat resistance of the heat-generating components. For example, for a motor, the upper threshold can be set to 58°C, and the lower threshold can be set to 32°C. The target temperature range is the target temperature ± a margin, with a margin of, for example, 4°C. The target temperature range falls between the upper and lower thresholds. The set liquid level is designed based on the unit's optimal operating level. Depending on actual usage, 1 / 2 or another ratio of the optimal level can be used as the set liquid level.

[0059] In some embodiments, the opening of the primary throttle valve and the opening of the secondary throttle valve are adjusted as follows:

[0060] D=D1+D2,D C =U×D;

[0061] When │△Tshdt│≤set deviation, it means the temperature of the heating component is effectively controlled, D1=0;

[0062] When │△Tshdt│>set deviation, it means that the cooling supply deviation of the cooling branch is large, and the throttle valve needs to be adjusted to adapt to the heat generation of the heating component 6, D1=A_EXV1×Kp_EXV1×△Tshdt+A_EXV1×Ki_EXV1×

[0063] (△Tshdt-△Tshdt'), △Tshdt=Tshd-Tshdt;

[0064] When Tdwc≥A_EXV1×dwc_EXV1, it means that the cooling capacity supply deviation of the evaporator is large, and the throttle valve needs to be adjusted to adapt to the load demand of the terminal equipment. D2=A_EXV1×Kp1_EXV1×△Tdwct, △Tdwct=Tdwc-A_EXV1×dwc_EXV1;

[0065] When Tdwc<A_EXV1×dwc_EXV1, it means that the cooling capacity of the evaporator is appropriate, and D2=0;

[0066] Among them, D is the opening adjustment of the first-stage throttle valve, D C is the opening adjustment of the secondary throttle valve, U is the proportional coefficient, Tshd is the actual heating component temperature superheat, Tshdt is the target heating component temperature superheat, and the calculation formula for the target heating component humidity superheat can be obtained by fitting experimental data, or the target heating component temperature superheat can be set to a fixed value to simplify the control logic. ΔTshdt is the heating component superheat deviation in the current cycle, ΔTshdt' is the heating component superheat deviation in the previous cycle, A_EXV1 is the correction coefficient, Kp_EXV1 and Kp1_EXV1 are both proportional coefficients, Ki_EXV1 is the integral coefficient, Tdwc is the actual evaporator end temperature difference, dwc_EXV1 is the target evaporator end temperature difference, and ΔTdwct is the evaporator end temperature difference deviation. In some embodiments, the set deviation is 0.1°C. In actual applications, the specific values ​​of the set deviation and coefficients such as A_EXV1 can be designed according to specific needs.

[0067] It should be understood that the opening, maintenance, or closing of the primary and secondary throttle valves is determined by the positive or negative value of D1 + D2. When D1 + D2 > 0, the primary throttle valve opens, and the secondary throttle valve opens accordingly. When D1 + D2 < 0, the primary throttle valve closes, and the secondary throttle valve closes accordingly. When D1 + D2 = 0, the primary and secondary throttle valves maintain their current openings. During the adjustment process of the primary throttle valve 4 and the secondary throttle valve 12, when the throttle valve is already at its minimum opening and D1 + D2 < 0, the throttle valve maintains its minimum opening. When the throttle valve is already at its maximum opening and D1 + D2 > 0, the throttle valve maintains its maximum opening.

[0068] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. The "throttle valve" mentioned above can be an electronic expansion valve, and the "control valve" can be a solenoid valve.

[0069] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Cooling system, including: A main circuit and a cooling branch for cooling heat-generating components, the main circuit having a compressor, a condenser, a flash unit and an evaporator connected in sequence, one end of the cooling branch being connected to the condenser via a cooling throttle valve, the other end of the cooling branch being provided with a flash flow path and an evaporation flow path that can be switched on and off, the flash flow path being connected to the flash unit, and the evaporation flow path being connected to the evaporator; characterized in that the evaporation flow path is equipped with a refrigerant pump.

2. The cooling system according to claim 1, characterized in that Also includes: a first detection module for detecting the amount of refrigerant supplied to the cooling system, wherein the refrigerant pump and the first detection module are both connected to a controller of the cooling system; When the evaporation flow path is connected, the controller turns on the refrigerant pump and controls the working state of the refrigerant pump according to the refrigerant supply amount.

3. The cooling system according to claim 2, characterized in that The first detection module adopts a liquid level sensor or a flow meter. The liquid level sensor is installed in the condenser or the evaporator, and the flow meter is installed on the cooling branch or the main circuit.

4. The cooling system according to claim 1, wherein: The main circuit is provided with a primary throttle valve and a secondary throttle valve. The primary throttle valve is connected in series between the condenser and the flash evaporator, and the secondary throttle valve is connected in series between the flash evaporator and the evaporator.

5. The cooling system according to claim 4, characterized in that Also includes: A second detection module is used to detect the temperature parameters of the main circuit and the cooling branch. The first-level throttle valve, the second-level throttle valve and the second detection module are all connected to the controller of the cooling system. The controller synchronously adjusts the opening of the first-level throttle valve and the second-level throttle valve according to the temperature parameters.

6. The cooling system according to claim 5, characterized in that The temperature parameters include: the actual temperature of the heat-generating component, the temperature of the refrigerant before and after flowing through the heat-generating component, the evaporation temperature of the evaporator, and the outlet temperature of the chilled water flowing out of the evaporator.

7. A control method for a cooling system, the control method being applied to the cooling system according to any one of claims 1 to 6, characterized in that: The following steps are involved: detecting the actual temperature of the heating component; switching the on / off states of the flash flow path and the evaporation flow path according to the actual temperature; After the evaporation flow path is connected, the working state of the refrigerant pump is controlled according to the refrigerant supply amount of the cooling system.

8. The control method according to claim 7, characterized in that: Controlling the working state of the refrigerant pump according to the refrigerant supply amount includes: When the refrigerant supply volume reaches or exceeds the set supply volume, maintaining the current opening of the refrigerant pump; When the refrigerant supply amount is lower than the set supply amount, the opening of the refrigerant pump is increased.

9. The control method according to claim 8, characterized in that: The refrigerant supply volume is the actual liquid level of the condenser, and the set supply volume is the set liquid level of the condenser; the opening of the refrigerant pump after enlargement is calculated by a setting function model, and the setting function model is: opening = (actual liquid level × 0.3 × rated flow) / 100.

10. The control method according to claim 7, characterized in that: Switching the on / off states of the flash flow path and the evaporation flow path according to the actual temperature includes: When the actual temperature is lower than a set lower limit threshold, the flash flow path is connected and the evaporation flow path is closed; When the actual temperature is higher than a set upper limit threshold, the flash flow path is closed and the evaporation flow path is connected.

11. The control method according to claim 10, characterized in that: Also includes: When the actual temperature is within the target temperature range, the opening of the first-stage throttle valve and the opening of the second-stage throttle valve remain unchanged; When the actual temperature is outside the target temperature range, the temperature parameters of the main circuit and the cooling branch are detected, and the openings of the first-stage throttle valve and the second-stage throttle valve are synchronously adjusted according to the temperature parameters.

12. The control method according to claim 11, characterized in that: Synchronously adjusting the opening of the first-stage throttle valve and the opening of the second-stage throttle valve according to the temperature parameter includes: D=D1+D2,D C =U×D; When │△Tshdt│≤set deviation, D1=0; When │△Tshdt│>set deviation, D1=A_EXV1×Kp_EXV1×△Tshdt+A_EXV1×Ki_EXV1×(△Tshdt-△Tshdt'), △Tshdt=Tshd-Tshdt; When Tdwc≥A_EXV1×dwc_EXV1, D2=A_EXV1×Kp1_EXV1×△Tdwct,△Tdwct=Tdwc-A_EXV1×dwc_EXV1; When Tdwc<A_EXV1×dwc_EXV1, D2=0; Among them, D is the opening adjustment of the first-stage throttle valve, D C is the opening adjustment amount of the secondary throttle valve, U is the proportional coefficient, Tshd is the actual superheat temperature of the heating component, Tshdt is the target superheat temperature of the heating component, △Tshdt is the superheat deviation of the heating component in the current cycle, △Tshdt' is the superheat deviation of the heating component in the previous cycle, A_EXV1 is the correction coefficient, Kp_EXV1 and Kp1_EXV1 are both proportional coefficients, Ki_EXV1 is the integral coefficient, Tdwc is the actual evaporator end temperature difference, dwc_EXV1 is the target evaporator end temperature difference, and △Tdwct is the evaporator end temperature difference deviation.

13. An air conditioning unit, characterized in that: The air conditioning unit adopts the cooling system according to any one of claims 1 to 6.

14. The air conditioning unit according to claim 13, wherein: The air conditioning unit is a centrifugal chiller.

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