Valve control method for refrigeration cycle system, refrigeration cycle system, and storage medium

Abstract

This application relates to a valve control method for a refrigeration cycle system, a refrigeration cycle system, and a storage medium. Upon receiving a start-up signal, the method controls the main circuit throttle valve to operate at a first anti-liquid slugging opening. When the refrigeration cycle branch includes a hot gas bypass branch, the method controls the hot gas bypass valve to operate at a first preset opening. When the refrigeration cycle branch includes a liquid injection bypass branch, after the load and compressor meet preset conditions, the method controls the liquid injection valve to operate at a second preset opening. And / or, upon receiving a stop signal, the method controls the main circuit throttle valve to operate at a second anti-liquid slugging opening. When the refrigeration cycle branch includes a liquid injection bypass branch, the liquid injection valve immediately closes. When the refrigeration cycle branch includes a hot gas bypass valve, the method controls the hot gas bypass valve to adjust to a third preset opening. After the main circuit throttle valve operates at the second anti-liquid slugging opening for a first preset time, the method controls the compressor to stop. This significantly reduces the risk of liquid carryover (oil slugging / liquid slugging) during the start-up / shutdown phases of the equipment, improving control reliability.

Description

Technical Field

[0001] This application relates to the field of refrigeration system technology, and in particular to a valve control method for a refrigeration cycle system, a refrigeration cycle system, and a storage medium. Background Technology

[0002] Testing equipment typically uses a refrigeration system as the cold source and heating elements as the heat source, providing a stable temperature supply to the load through a thermo-cold confrontation method. The temperature of electronic components is then controlled at the load level to perform low-temperature, room-temperature, and high-temperature tests. Traditional refrigeration cycle systems often only focus on temperature control during stable operation, ensuring the system can start normally during startup, neglecting the risk of liquid carryover during startup / shutdown, resulting in low control reliability. Summary of the Invention

[0003] Therefore, it is necessary to provide a valve control method, refrigeration cycle system, and storage medium for a refrigeration cycle system that can reduce the risk of liquid carryover during start-up / shutdown and improve control reliability, in order to address the above problems.

[0004] The first aspect of this application provides a valve control method for a refrigeration cycle system. The refrigeration cycle system has a main refrigeration circuit equipped with a compressor, a condenser, a main circuit expansion valve, and a load evaporator, which are sequentially connected and closed. A refrigeration cycle branch is branched onto the main refrigeration circuit. The refrigeration cycle branch includes a hot gas bypass branch and / or a liquid injection bypass branch. A hot gas bypass valve is provided on the hot gas bypass branch, and a liquid injection valve is provided on the liquid injection bypass branch. The method includes:

[0005] Upon receiving the start-up signal, the main circuit throttle valve is controlled to operate at a first anti-liquid hammer opening. When the refrigeration cycle branch includes the hot gas bypass branch, the hot gas bypass valve is controlled to operate at a first preset opening. When the refrigeration cycle branch includes the liquid injection bypass branch, the liquid injection valve is controlled to operate at a second preset opening after the load and the compressor meet preset conditions.

[0006] And / or, upon receiving a shutdown signal, the main circuit throttle valve is controlled to operate at a second anti-liquid slugging opening degree; when the refrigeration cycle branch includes the liquid injection bypass branch, the liquid injection valve is immediately closed; when the refrigeration cycle branch includes the hot gas bypass valve branch, the hot gas bypass valve is controlled to adjust to a third preset opening degree; after the main circuit throttle valve operates at the second anti-liquid slugging opening degree for a first preset time, the compressor is controlled to shut down.

[0007] In one embodiment, after the step of controlling the hot gas bypass valve to operate at a first preset opening degree when the refrigeration cycle branch includes the hot gas bypass branch, the method further includes:

[0008] The hot gas bypass valve operates at the first preset opening degree until a preset time, then the hot gas bypass valve switches to the first control mode. In the first control mode, the opening degree of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

[0009] In one embodiment, the refrigeration main circuit includes a cascaded high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit, which are thermally coupled through a condenser-evaporator; the hot gas bypass valve operates at the first preset opening degree until a preset time, and the step of switching the hot gas bypass valve to the first control mode includes:

[0010] After the compressor in the low-temperature refrigeration circuit starts, the timing begins. After a second preset time delay, the preset time is reached. The hot gas bypass valve switches to the first control mode. In the first control mode, the opening degree of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

[0011] In one embodiment, different load operating temperatures correspond to different second preset opening degrees; when the refrigeration cycle branch includes the liquid injection bypass branch, after the load and the compressor meet preset conditions, the step of controlling the liquid injection valve to operate at the second preset opening degree specifically includes:

[0012] If the load operating temperature is greater than the preset temperature, and the timing starts after the compressor starts, after a third preset time delay, the injection valve operates at the second preset opening degree corresponding to the load operating temperature.

[0013] In one embodiment, different load operating temperatures correspond to different second preset opening degrees. The refrigeration main circuit includes cascaded high-temperature stage refrigeration circuits and low-temperature stage refrigeration circuits, which are thermally coupled through a condenser-evaporator. When the refrigeration cycle branch includes the liquid injection bypass branch, after the load and the compressor meet preset conditions, the step of controlling the liquid injection valve to operate at the second preset opening degree specifically includes:

[0014] If the load operating temperature is greater than the preset temperature, and the timing starts after the compressor in the low-temperature refrigeration circuit is started, after a third preset time delay, the liquid injection valve operates at the second preset opening degree corresponding to the load operating temperature.

[0015] In one embodiment, after the step of controlling the main throttle valve to operate at a first anti-liquid hammer opening degree after receiving the power-on signal, the method further includes:

[0016] After the main throttle valve maintains the first anti-liquid hammer opening for a fourth preset time, the main throttle valve switches to feedback adjustment mode. In the feedback adjustment mode, the opening of the main throttle valve is adjusted according to the target physical parameters and the actual physical parameters, wherein the physical parameters include one or more of temperature, pressure, superheat and subcooling.

[0017] In one embodiment, after the step of controlling the compressor to stop following the operation of the main throttle valve at the second anti-liquid hammer opening for a first preset time, the method further includes:

[0018] After the main throttle valve maintains the second anti-liquid hammer opening for a fifth preset time, the opening of the main throttle valve is switched to a preset balanced opening, which is greater than the first anti-liquid hammer opening and the second anti-liquid hammer opening.

[0019] When the refrigeration cycle branch includes the hot gas bypass branch, the hot gas bypass valve operates at the fourth preset opening degree for the fifth preset duration and then closes.

[0020] In one embodiment, prior to the step of controlling the main throttle valve to operate at a first preset opening, the method further includes:

[0021] Upon receiving the power-on signal, the main throttle valve, the hot gas bypass valve, and / or the liquid injection valve perform a reset self-test step.

[0022] A second aspect of this application provides a refrigeration cycle system, including a refrigeration main circuit and a controller. The refrigeration main circuit is provided with a compressor, a condenser, a main circuit expansion valve, and a load evaporator, which are connected and closed in sequence. A refrigeration cycle branch is connected to the refrigeration main circuit. The refrigeration cycle branch includes a hot gas bypass branch and / or the liquid injection bypass branch. A hot gas bypass valve is provided on the hot gas bypass branch, and a liquid injection valve is provided on the liquid injection bypass branch. The controller controls the valves according to the above method.

[0023] A third aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0024] The aforementioned valve control method for the refrigeration cycle system, the refrigeration cycle system, and the storage medium, upon receiving a start-up signal, control the main circuit throttle valve to operate at a first anti-liquid slugging opening. When the refrigeration cycle branch includes a hot gas bypass branch, the hot gas bypass valve is controlled to operate at a first preset opening. When the refrigeration cycle branch includes a liquid injection bypass branch, after the load and compressor meet preset conditions, the liquid injection valve is controlled to operate at a second preset opening. And / or, upon receiving a stop signal, control the main circuit throttle valve to operate at a second anti-liquid slugging opening. When the refrigeration cycle branch includes a liquid injection bypass branch, the liquid injection valve immediately closes. When the refrigeration cycle branch includes a hot gas bypass valve, the hot gas bypass valve is controlled to adjust to a third preset opening. After the main circuit throttle valve operates at the second anti-liquid slugging opening for a first preset time, the compressor is controlled to stop. This significantly reduces the risk of liquid carryover (oil slugging / liquid slugging) during the start-up / shutdown phases of the equipment, improving control reliability. Attached Figure Description

[0025] Figure 1 This is a flowchart of a valve control method for a refrigeration cycle system in one embodiment;

[0026] Figure 2 This is a schematic diagram of the refrigeration cycle system in one embodiment;

[0027] Figure 3 This is a flowchart of a valve control method for a refrigeration cycle system in another embodiment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. It is understood that the term "connection" in the following embodiments, if the connected circuits, modules, units, etc., transmit electrical signals or data to each other, should be understood as "electrical connection," "communication connection," etc.

[0030] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, the term “and / or” as used in this specification includes any and all combinations of the associated listed items.

[0031] For semiconductor industry testing equipment, not only is high temperature control stability required for providing a low-temperature environment, but also excellent reliability is essential to ensure a longer service life. Currently, in cascade refrigeration systems, system temperature control is primarily achieved using valves (electronic expansion valves / thermal expansion valves / solenoid valves). The main evaporation temperature of the cryogenic stage system is typically controlled by an electronic expansion valve, while the bypass branch regulating system parameters (pressure / temperature) is usually controlled by either an electronic expansion valve or a solenoid valve. This control approach focuses only on temperature control during stable operation, neglecting the risk of liquid carryover during start-up / shutdown.

[0032] Based on this, this application provides a valve control method for a refrigeration cycle system. Upon receiving a start-up signal, the method controls the main circuit throttle valve to operate at a first anti-liquid hammer opening. When the refrigeration cycle branch includes a hot gas bypass branch, the method controls the hot gas bypass valve to operate at a first preset opening. When the refrigeration cycle branch includes a liquid injection bypass branch, after the load and compressor meet preset conditions, the method controls the liquid injection valve to operate at a second preset opening. And / or, upon receiving a stop signal, the method controls the main circuit throttle valve to operate at a second anti-liquid hammer opening. When the refrigeration cycle branch includes a liquid injection bypass branch, the liquid injection valve immediately closes. When the refrigeration cycle branch includes a hot gas bypass valve, the method controls the hot gas bypass valve to adjust to a third preset opening. After the main circuit throttle valve operates at the second anti-liquid hammer opening for a first preset time, the method controls the compressor to stop. By controlling each valve to a fixed opening during the start-up / shutdown phases, liquid refrigerant / refrigeration oil is prevented from being drawn into the return gas end of the load evaporator in large quantities, thus avoiding liquid slugging / oil slugging. This significantly reduces the risk of liquid carryover during the return gas phases of the equipment and improves control reliability.

[0033] In one embodiment, a valve control method for a refrigeration cycle system is provided. The refrigeration main circuit of the refrigeration cycle system includes a compressor, a condenser, a main circuit expansion valve, and a load evaporator, which are sequentially connected and closed. A refrigeration cycle branch is branched onto the main circuit. The refrigeration cycle branch includes a hot gas bypass branch and / or a liquid injection bypass branch. A hot gas bypass valve is provided on the hot gas bypass branch, and a liquid injection valve is provided on the liquid injection bypass branch. Figure 1 As shown, the method includes step S110 and / or step S140.

[0034] Step S110: After receiving the start-up signal, control the main circuit throttle valve to operate at the first anti-liquid hammer opening degree. When the refrigeration cycle branch includes a hot gas bypass branch, control the hot gas bypass valve to operate at the first preset opening degree. When the refrigeration cycle branch includes a liquid injection bypass branch, control the liquid injection valve to operate at the second preset opening degree after the load and compressor meet the preset conditions.

[0035] The main refrigeration circuit can be a single-stage refrigeration circuit or a multi-stage cascade refrigeration circuit. For example... Figure 2 As shown, when the main refrigeration circuit adopts a single-stage refrigeration circuit, it is equipped with a compressor 5, a condenser 4, a main circuit throttling valve 8, and a load evaporator (not shown in the figure), which are connected and closed in sequence. The load evaporator is used for heat exchange with the load end. A hot gas bypass valve 7 is provided on the hot gas bypass branch, and a liquid injection valve 12 is provided on the liquid injection bypass branch.

[0036] Furthermore, the main refrigeration circuit (when using a single-stage refrigeration circuit) may also include an oil separator 6, a regenerator 9, a first shut-off valve 10, a second shut-off valve 11, and an expansion tank 13. The oil separator 6 connects to the compressor 5, the condenser 4, and the expansion tank 13 (specifically connected to the output port of the expansion tank 13). The main circuit throttle valve 8 connects to the condenser 4 and the regenerator 9. The regenerator 9 connects to the main circuit throttle valve 8 and the first shut-off valve 10. The hot gas bypass valve 7 connects to the oil separator 6 and the first shut-off valve 10. The first shut-off valve 10 connects to one end of the load evaporator, and the second shut-off valve 11 connects to the other end of the load evaporator and the regenerator 9. The regenerator 9 also connects to the expansion tank 13 (specifically connected to the input port of the expansion tank 13) and the input port of the compressor 5. The liquid injection valve 12 connects to the condenser 4 and the return gas pipeline (located between the load evaporator and the input port of the compressor 5). The first shut-off valve 10 and the second shut-off valve 11 connect to the load evaporator to control the flow path. The hot gas bypass branch runs from the discharge end of compressor 5 to the shut-off valve 10 to mix with the main refrigerant. Its main function is to bypass and regulate the cooling capacity supplied to the load, and to increase the superheat of the low-temperature stage return gas. The liquid injection bypass branch runs from the rear end of condenser 4 to the return gas end of the load evaporator. Its main function is to reduce the low-temperature stage return gas temperature. Specifically, when the liquid injection valve 12 is open, it mixes the refrigerant output from condenser 4 with the refrigerant output from the load evaporator to reduce the return gas temperature and prevent excessive superheat from causing the discharge temperature to be too high (mainly used in high-temperature production conditions, such as >50℃).

[0037] In addition, the main refrigeration circuit (when a single-stage refrigeration circuit is used) may also include a first angle valve 14 and a second angle valve 15. The first angle valve 14 is located at the inlet of the expansion tank 13, and the second angle valve 15 is located at the outlet of the expansion tank 13. The main function of the expansion tank 13 is to stabilize the system pressure when the unit is not running, and to prevent damage to system piping components. Whether the expansion tank 13 is in use can be adjusted by controlling the opening and closing of the first angle valve 14 and the second angle valve 15.

[0038] The main throttle valve 8 can be an electronic expansion valve, the hot gas bypass valve 7 can be an electronic expansion valve or a solenoid valve, and the injection valve 12 can be an electronic expansion valve or a solenoid valve. The main throttle valve 8, hot gas bypass valve 7, injection valve 12, first shut-off valve 10, second shut-off valve 11, first angle valve 14, and second angle valve 15 can be connected to the controller for on / off / opening degree control. The controller can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices, such as smartwatches, smart bracelets, and head-mounted devices.

[0039] When the main refrigeration circuit adopts a multi-stage cascade refrigeration circuit (taking a two-stage cascade refrigeration circuit as an example), it includes cascaded high-temperature stage refrigeration circuits and low-temperature stage refrigeration circuits. The low-temperature stage refrigeration circuit can use the above-mentioned structure, with compressor 5 serving as the low-temperature stage compressor and condenser 4 serving as a condenser-evaporator for heat exchange between the low-temperature stage and high-temperature stage refrigeration circuits. In the high-temperature stage refrigeration circuit, high-temperature stage compressor 1, water-cooled condenser 2, thermostatic expansion valve 3, and condenser-evaporator are connected in sequence. The condenser-evaporator is connected to high-temperature stage compressor 1, and water-cooled condenser 2 is used for heat exchange with an external chiller.

[0040] In the low-temperature stage refrigeration circuit, the refrigerant after heat exchange with the high-temperature stage refrigeration circuit in the condenser-evaporator is transported to the regenerator 9 through the main throttling valve 8 for further heat exchange. Then, it is transported to the load evaporator through the first shut-off valve 10. The refrigerant output from the load evaporator is transported to the regenerator 9 through the second shut-off valve 11, where it exchanges heat with the refrigerant output from the main throttling valve 8 before being transported to the low-temperature stage compressor. The refrigerant output from the low-temperature stage compressor is returned to the condenser-evaporator through the oil separator 6 for heat exchange with the high-temperature stage circulation circuit. When the liquid injection valve 12 is open, the refrigerant output from the condenser-evaporator is transported to both the main throttling valve 8 and the liquid injection valve 12. The refrigerant output from the liquid injection valve 12 mixes with the refrigerant output from the second shut-off valve 11 to lower the low-temperature stage return gas temperature. The mixed refrigerant is then sent to the regenerator 9 for heat exchange with the refrigerant output from the main throttling valve 8. In addition, when the hot gas bypass valve 7 is open, part of the refrigerant output from the oil separator 6 is also mixed with the refrigerant output from the regenerator 9 through the hot gas bypass valve 7, and then transported to the load evaporator through the first shut-off valve 10.

[0041] Specifically, after receiving the start-up signal, the controller controls the main circuit throttle valve 8 to operate at a first anti-liquid-slugging opening. If the refrigeration cycle branch includes a hot gas bypass branch, the controller also controls the hot gas bypass valve 7 to operate at a first preset opening. If the refrigeration cycle branch includes a liquid injection bypass branch, the controller controls the liquid injection valve 12 to operate at a second preset opening after the load and compressor meet preset conditions. The first anti-liquid-slugging opening, the first preset opening, and the second preset opening serve as fixed openings for the start-up phase, and their specific values ​​are not unique and can be set according to actual needs. In this embodiment, the first anti-liquid-slugging opening can be 5%, the first preset opening can be 10%, and the second preset opening can be 100%. Furthermore, different second preset openings can be set according to different load operating temperatures. Similarly, the specific content of the preset conditions is not unique and can be set according to actual conditions.

[0042] Hot gas bypass valve 7 and liquid injection valve 12 are auxiliary temperature control components. During startup, hot gas bypass valve 7 is initially controlled to operate at a first preset opening degree (e.g., 10%). The liquid injection valve branch transmits low-temperature liquid refrigerant, used to regulate the return gas superheat. During startup, liquid injection valve 12 cannot be directly opened; it is closed by default (0% opening). This is because, firstly, the external load does not undergo sufficient thermal resistance during startup, leading to liquid carryover in the return gas; secondly, it increases the refrigerant flow at the return gas end of the load evaporator, increasing the risk of liquid slugging. Therefore, after the load and compressor meet preset conditions, liquid injection valve 12 needs to be controlled to operate at a second preset opening degree (e.g., kept open at 100%).

[0043] In one embodiment, such as Figure 3 As shown, after receiving the power-on signal in step S110, the method further includes step S120: after the main throttle valve maintains the first anti-liquid hammer opening for a fourth preset time, the main throttle valve switches to feedback regulation mode.

[0044] Similarly, the value of the fourth preset duration is not unique and can be set according to actual needs. After the main circuit throttle valve 8 maintains the first anti-liquid slugging opening for the fourth preset duration, the controller switches the main circuit throttle valve 8 to feedback regulation mode. By maintaining the main circuit throttle valve 8 at the initial first anti-liquid slugging opening for a period of time before switching to feedback regulation mode, the refrigerant circulation flow is reduced while ensuring that the system does not trigger a high-pressure alarm, thus preventing a large amount of liquid refrigerant / refrigeration oil from being drawn into the return gas end of the load evaporator and causing oil slugging (especially during the start-up phase of continuous start-stop).

[0045] In feedback control mode, the controller adjusts the opening of the main throttle valve 8 based on target and actual physical parameters. These physical parameters include one or more of temperature, pressure, superheat, and subcooling. PID temperature control can be performed by combining the collected actual physical parameters and the set target physical parameters to adjust the opening of the main throttle valve 8. Temperature can include the system set temperature, exhaust temperature, etc., and pressure can include exhaust pressure, etc. The exhaust temperature can be calculated based on the detected exhaust pressure. For example, when both the actual and target physical parameters include exhaust temperature, the actual exhaust pressure of the compressor 5 can be monitored in real time and converted to obtain the actual exhaust temperature. The actual exhaust temperature is then compared with the set target exhaust temperature, and the opening of the main throttle valve 8 is adjusted based on the comparison result. When both actual and target physical parameters include pressure (e.g., exhaust pressure) and superheat (e.g., return gas superheat), the system can be pre-determined by debugging to determine the correspondence between the pressure difference, superheat difference, and target opening, and stored in the controller. In feedback adjustment mode, the actual pressure and actual superheat of compressor 5 are monitored in real time. The actual pressure and target pressure are compared to determine the pressure difference, and the actual superheat is compared to the target superheat to determine the superheat difference. Then, the corresponding target opening is determined by combining the pressure difference and superheat difference, and the opening of the main throttle valve 8 is adjusted to the target opening.

[0046] It is understood that the above is merely an example of adjusting the opening of the main throttle valve 8 in the feedback regulation mode by combining one or two physical parameters. In other embodiments, different types of physical parameters may be used, or more physical parameters may be combined as the basis for adjusting the opening of the main throttle valve 8, which will not be elaborated here.

[0047] Furthermore, in step S110, when the refrigeration cycle branch includes a hot gas bypass branch, after controlling the hot gas bypass valve to operate at a first preset opening, the method further includes step S130: the hot gas bypass valve 7 operates at the first preset opening until a preset time, and then the hot gas bypass valve 7 switches to a first control mode. In the first control mode, the opening of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

[0048] It is understandable that the setting method for the preset time is not unique and can be adjusted according to the structure of the refrigeration main circuit. Specifically, when the refrigeration main circuit adopts a single-stage refrigeration circuit, the controller controls the compressor 5 to start according to the received start signal. After the compressor 5 starts, the timing begins. During the timing, the first preset opening degree of the hot gas bypass valve 7 remains unchanged. After maintaining this for a second preset duration, the preset time begins, and the hot gas bypass valve 7 switches to the first control mode. The value of the second preset duration is also not unique and can be set according to actual needs. In this embodiment, the second preset duration can be set to 30 seconds.

[0049] When the main refrigeration circuit adopts a multi-stage cascaded refrigeration circuit, it includes a cascaded high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit, which are thermally coupled through a condenser-evaporator. Step S130 includes: starting a timer after the compressor 5 of the low-temperature stage refrigeration circuit starts, delaying for a second preset time, and then entering a preset time, the hot gas bypass valve 7 switches to the first control mode. In the first control mode, the opening degree of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

[0050] like Figure 2 As shown, when a multi-stage cascade refrigeration circuit is used in the main refrigeration circuit, the controller controls the high-temperature stage compressor 1 to start based on the received start signal. Compressor 5 (low-temperature stage compressor) starts after a certain delay following the start of high-temperature stage compressor 1, or after determining that the return gas pressure of high-temperature stage compressor 1 has reached a certain limit value. The controller starts timing after the low-temperature stage compressor starts, and during the timing period, the first preset opening of the hot gas bypass valve 7 remains unchanged. After maintaining the second preset duration (e.g., 30 seconds), it enters the preset time, and the hot gas bypass valve 7 switches to the first control mode. In the first control mode, the controller can perform PID control based on the target liquid outlet temperature and the actual liquid outlet temperature of the main refrigeration circuit, adjusting the opening of the hot gas bypass valve 7 to make the actual liquid outlet temperature of the main refrigeration circuit close to the target liquid outlet temperature, i.e., the actual liquid outlet temperature is equal to the target liquid outlet temperature, or the actual liquid outlet temperature is less than the target liquid outlet temperature but the difference between the two is within the allowable error range.

[0051] It should be noted that when a higher evaporation temperature is required from the refrigeration cycle system, auxiliary temperature control is activated. After the hot gas bypass valve 7 operates at the first preset opening for a preset time, it switches to the first control mode. PID control is then applied based on the target and actual liquid outlet temperatures of the main refrigeration circuit to adjust the opening of the hot gas bypass valve 7. If auxiliary temperature control is not required during the stable operation phase of the refrigeration cycle system, the hot gas bypass valve 7 operates at the first preset opening for a preset time and then closes. During the stable operation phase, superheat control is primarily achieved by adjusting the main circuit throttle valve 8.

[0052] In this embodiment, after controlling the hot gas bypass valve 7 to operate at the first preset opening during the start-up phase, the timing starts after the low-temperature stage compressor starts, and after a second preset delay, the original control logic is restored (if auxiliary temperature control is not required during the stable operation phase, it is turned off; if auxiliary temperature control is required, the hot gas bypass valve 7 switches to the first control mode). During the start-up phase, the refrigerant at the return gas end of the load evaporator can be heated and evaporated to avoid the refrigerant in the load evaporator not evaporating sufficiently during the start-up phase, resulting in liquid carryover in the return gas.

[0053] In one embodiment, different load operating temperatures correspond to different second preset opening degrees. In step S110, when the refrigeration cycle branch includes a liquid injection bypass branch, after the load and compressor meet preset conditions, the liquid injection valve is controlled to operate at the second preset opening degree. Specifically, if the load operating temperature is greater than the preset temperature, and timing starts after the compressor 5 starts, after a third preset time delay, the liquid injection valve 12 operates at the second preset opening degree corresponding to the load operating temperature.

[0054] Similarly, the main refrigeration circuit can be a single-stage refrigeration circuit or a multi-stage cascaded refrigeration circuit. When the main refrigeration circuit adopts a multi-stage cascaded refrigeration circuit, this application takes a two-stage cascaded refrigeration circuit as an example, including a cascaded high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit. The high-temperature stage refrigeration circuit and the low-temperature stage refrigeration circuit are thermally coupled through a condenser-evaporator. In step S110, when the refrigeration cycle branch includes a liquid injection bypass branch, after the load and compressor meet the preset conditions, the liquid injection valve is controlled to operate at a second preset opening degree. Specifically, if the load operating temperature is greater than the preset temperature, and the timing starts after the compressor 5 of the low-temperature stage refrigeration circuit starts, after a third preset time delay, the liquid injection valve 12 operates at the second preset opening degree corresponding to the load operating temperature.

[0055] The values ​​of the preset temperature and the third preset duration are not unique and can be set according to actual needs. If the load operating temperature is higher than the preset temperature, the load can be considered as a high-temperature production temperature condition. After the compressor 5 starts, the timing starts and after a delay of the third preset duration (such as 30 seconds), the liquid injection valve 12 is controlled to operate at the second preset opening degree corresponding to the load operating temperature, which is more in line with the actual operating conditions.

[0056] Furthermore, before controlling the main throttle valve to operate at the first preset opening degree in step S110, the method further includes: after receiving the start-up signal, the main throttle valve, the hot gas bypass valve, and / or the injection valve perform a reset self-test step. After receiving the start-up signal, the controller first performs a reset process, i.e., a valve self-test process, on the main throttle valve 8, the hot gas bypass valve 7 (if any), and the injection valve 12 (if any), to prevent the accumulation of valve body step loss from causing control failure. After the valve reset self-test passes, step S110 is executed to perform the corresponding fixed opening degree control for each valve during the start-up phase.

[0057] Step S140: After receiving the shutdown signal, control the main circuit throttle valve to operate at the second anti-liquid hammer opening degree. When the refrigeration cycle branch includes the liquid injection bypass branch, the liquid injection valve is immediately closed. When the refrigeration cycle branch includes the hot gas bypass valve branch, control the hot gas bypass valve to adjust to the third preset opening degree. After the main circuit throttle valve operates at the second anti-liquid hammer opening degree for a first preset time, control the compressor to stop.

[0058] Specifically, the values ​​of the second anti-liquid hammer opening, the third preset opening, and the first preset duration are not unique and can be set according to actual needs. The second anti-liquid hammer opening and the third preset opening serve as the fixed opening for shutdown during the shutdown phase. The fixed opening for each valve during the shutdown phase can be the same as or different from the fixed opening for startup during the startup phase. In this embodiment, after receiving the shutdown signal, the controller adjusts each valve to the corresponding fixed shutdown opening (liquid injection valve 12 closes) regardless of its current opening, and then controls the compressor 5 to shut down after a first preset duration (e.g., 30 seconds). During the shutdown phase, the main function of the main circuit throttle valve 8 is to reduce the refrigerant flow rate. The hot gas bypass valve 7 is used to reduce the suction and discharge pressure difference, thereby reducing the risk of liquid carryover during the shutdown phase while weakening the suction effect at the return end of the load evaporator. Upon receiving the shutdown signal, the controller immediately controls the liquid injection valve 12 to close (fixed opening of 0%) to prevent the low-temperature liquid refrigerant from continuously returning to the suction end of the compressor 5 after the external load is no longer heated.

[0059] It should be noted that after the controller receives a shutdown signal and switches the opening of the main throttle valve 8, the opening of the main throttle valve 8 after the switch (the second anti-liquid slugging opening) is not fixed compared to the opening before the switch. That is, the opening of the main throttle valve 8 after the switch may be larger or smaller. For example, if the set temperature is low during normal temperature control, the main throttle valve 8 and the hot gas bypass valve 7 need to work together to adjust the refrigerant state at the suction end of the compressor 5. In this case, the opening of the main throttle valve 8 may be relatively small. However, when the system is shut down, the opening of the main throttle valve 8 after the switch (the second anti-liquid slugging opening) may be larger than the opening before the switch.

[0060] The second anti-liquid hammer opening (e.g., 10%) and the third preset opening are determined during the system temperature control design. If the system is in a stable temperature control state before shutdown, the controller may adjust the opening of the main throttle valve 8 from 20% to 10% and the hot gas bypass valve 7 to decrease its opening after receiving the shutdown signal. If the system is not in a stable temperature control state before shutdown, that is, the main throttle valve 8 and the hot gas bypass valve 7 are mismatched before receiving the shutdown signal, the controller may adjust the opening of the main throttle valve 8 and the hot gas bypass valve 7 in opposite directions after receiving the shutdown signal, that is, one of the main throttle valve 8 and the hot gas bypass valve 7 is increased and the other is decreased.

[0061] In one embodiment, continue to refer to Figure 3 After the main circuit throttle valve operates at the second anti-liquid hammer opening for a first preset time in step S140 and the compressor is stopped, the method further includes step S150: after the main circuit throttle valve maintains the second anti-liquid hammer opening for a fifth preset time, the opening of the main circuit throttle valve is switched to a preset balanced opening. When the refrigeration cycle branch includes a hot gas bypass branch, the hot gas bypass valve operates at the fourth preset opening for a fifth preset time and then closes.

[0062] The preset balance opening is greater than the first and second anti-liquid hammer openings. For example, if the first anti-liquid hammer opening is set to 5% and the second anti-liquid hammer opening is set to 10%, then the preset balance opening can be set to 20%. The values ​​of the fourth preset opening and the fifth preset duration are not unique and can be adjusted according to actual needs. After the controller maintains the second anti-liquid hammer opening at the main circuit throttle valve for the fifth preset duration (e.g., 30 seconds), it switches the opening of the main circuit throttle valve 8 to the preset balance opening. When an external load is heated to a high temperature and the refrigerant compressor is not turned on, the refrigerant in the load channel needs to flow. In this case, a larger preset balance opening needs to be set for the main circuit throttle valve 8 to ensure that the system can maintain flow and that the internal pressure quickly balances after shutdown, avoiding high resistance during the next startup.

[0063] When the refrigeration cycle branch includes a hot gas bypass branch, the controller will switch the hot gas bypass valve 7 to the fourth preset opening and run it for the fifth preset time (e.g., 30 seconds) before closing the hot gas bypass valve 7 (closed under static conditions). This facilitates rapid pressure balance in the circuit. The principle is as follows: For the low-temperature refrigerant used, pressure balance essentially means that the discharge and suction pressures are basically the same (in a gaseous state at room temperature). Delaying the closure of the hot gas bypass valve 7 during the shutdown phase is equivalent to directly connecting the discharge end of the compressor 5 to the return end of the load evaporator, bypassing the main throttling valve 8. Whether from the perspective of having an additional discharge and suction connection branch or from the perspective of the high discharge temperature facilitating the low suction temperature evaporation, this is beneficial for pressure balance.

[0064] The valve control method for the above-mentioned refrigeration cycle system has the following advantages compared with the prior art:

[0065] 1. In the prior art, the hot gas bypass valve 7 only opens to a certain degree during operation based on the superheat of the return gas and the exhaust temperature of the low-temperature stage system. It does not maintain a fixed opening during the start / stop phase, and therefore cannot adjust the intake and exhaust pressure difference and the return gas temperature, thus failing to prevent liquid slugging. In this application, the hot gas bypass valve 7 is set to a fixed opening and maintained for a period of time during the start / stop phase, which can greatly reduce the risk of liquid slugging.

[0066] 2. In the prior art, the liquid injection valve 12 will remain open under high-temperature production conditions to avoid excessively high return gas overheating. Currently, it opens when the compressor starts up, but the external load has not yet started thermal resistance, resulting in a large amount of liquid refrigerant returning to the compressor. In this application, the liquid injection valve 12 opens with a delay according to the compressor 5 start-up time, which effectively reduces the risk of liquid slugging.

[0067] 3. In existing technology, the main circuit throttle valve 8 is mainly used to regulate the refrigerant flow and evaporation temperature at the load end. During startup, it operates at a fixed opening degree, but during shutdown, upon receiving a shutdown signal, it directly switches back to the initial fixed opening degree. This causes a sudden increase in the amount of refrigerant returning to the system, exacerbating the risk of liquid slugging. In this application, upon receiving a shutdown signal, the main circuit throttle valve 8 is controlled to operate at a fixed opening degree (reducing the refrigerant flow), and the compressor 5 is controlled to stop after a certain delay. The hot gas bypass valve 7, in conjunction with reducing the suction and discharge pressure difference, reduces the suction effect at the return gas end of the load evaporator, effectively reducing the risk of liquid slugging.

[0068] It should be understood that although the steps in the flowcharts of the embodiments described above are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the embodiments described above may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0069] In one embodiment, such as Figure 2 As shown, a refrigeration cycle system is also provided, including a main refrigeration circuit and a controller. The main refrigeration circuit is equipped with a compressor 5, a condenser 4, a main circuit expansion valve 8, and a load evaporator, which are sequentially connected and closed. A refrigeration cycle branch is branched onto the main refrigeration circuit, including a hot gas bypass branch and / or a liquid injection bypass branch. A hot gas bypass valve 7 is provided on the hot gas bypass branch, and a liquid injection valve 12 is provided on the liquid injection bypass branch. The controller controls the valves according to the above method. The controller can be, but is not limited to, various personal computers, laptops, smartphones, tablets, and portable wearable devices. Portable wearable devices can be smartwatches, smart bracelets, head-mounted devices, etc.

[0070] The refrigeration main circuit can be a single-stage refrigeration circuit or a multi-stage cascade refrigeration circuit. When the refrigeration main circuit adopts a multi-stage cascade refrigeration circuit, this application takes a two-stage cascade refrigeration circuit as an example, which includes a cascaded high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit. The high-temperature stage refrigeration circuit and the low-temperature stage refrigeration circuit are thermally coupled through a condenser-evaporator.

[0071] It is understood that the specific embodiments of the above-mentioned refrigeration cycle system have been explained in detail in the valve control method of the above-mentioned refrigeration cycle system, and will not be repeated here.

[0072] In one embodiment, a computer-readable storage medium is also provided, on which a computer program is stored, which, when executed by a processor, implements the steps of the above method.

[0073] In one embodiment, a computer program product is also provided, including a computer program that, when executed by a processor, implements the steps of the above-described method.

[0074] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The processors involved in the embodiments provided in this application can be general-purpose processors, central processing units, graphics processors, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited thereto.

[0075] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0076] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A valve control method for a refrigeration cycle system, characterized in that, The refrigeration main circuit of the refrigeration cycle system is equipped with a compressor, condenser, main circuit expansion valve, and load evaporator, which are sequentially connected and closed. A refrigeration cycle branch is branched onto the main refrigeration circuit. The refrigeration cycle branch includes a hot gas bypass branch and / or a liquid injection bypass branch. A hot gas bypass valve is provided on the hot gas bypass branch, and a liquid injection valve is provided on the liquid injection bypass branch. The method includes: Upon receiving the start-up signal, the main circuit throttle valve is controlled to operate at a first anti-liquid hammer opening. When the refrigeration cycle branch includes the hot gas bypass branch, the hot gas bypass valve is controlled to operate at a first preset opening. When the refrigeration cycle branch includes the liquid injection bypass branch, the liquid injection valve is controlled to operate at a second preset opening after the load and the compressor meet preset conditions. And / or, upon receiving a shutdown signal, the main circuit throttle valve is controlled to operate at a second anti-liquid slugging opening degree; when the refrigeration cycle branch includes the liquid injection bypass branch, the liquid injection valve is immediately closed; when the refrigeration cycle branch includes the hot gas bypass valve branch, the hot gas bypass valve is controlled to adjust to a third preset opening degree; after the main circuit throttle valve operates at the second anti-liquid slugging opening degree for a first preset time, the compressor is controlled to shut down.

2. The method according to claim 1, characterized in that, After the step of controlling the hot gas bypass valve to operate at a first preset opening degree when the refrigeration cycle branch includes the hot gas bypass branch, the method further includes: The hot gas bypass valve operates at the first preset opening degree until a preset time, then the hot gas bypass valve switches to the first control mode. In the first control mode, the opening degree of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

3. The method according to claim 2, characterized in that, The main refrigeration circuit includes a cascaded high-temperature stage refrigeration circuit and a low-temperature stage refrigeration circuit, which are thermally coupled through a condenser-evaporator; the hot gas bypass valve operates at the first preset opening degree until a preset time, and the step of switching the hot gas bypass valve to the first control mode includes: After the compressor in the low-temperature refrigeration circuit starts, the timing begins. After a second preset time delay, the preset time is reached. The hot gas bypass valve switches to the first control mode. In the first control mode, the opening degree of the hot gas bypass valve is adjusted according to the target liquid outlet temperature and the actual liquid outlet temperature.

4. The method according to claim 1, characterized in that, Different load conditions correspond to different second preset opening degrees; when the refrigeration cycle branch includes the liquid injection bypass branch, after the load and the compressor meet preset conditions, the specific steps of controlling the liquid injection valve to operate at the second preset opening degree include: If the load operating temperature is greater than the preset temperature, and the timing starts after the compressor starts, after a third preset time delay, the injection valve operates at the second preset opening degree corresponding to the load operating temperature.

5. The method according to claim 1, characterized in that, Different load conditions correspond to different second preset opening degrees. The main refrigeration circuit includes cascaded high-temperature and low-temperature refrigeration circuits, which are thermally coupled through a condenser-evaporator. When the refrigeration cycle branch includes the liquid injection bypass branch, the steps of controlling the liquid injection valve to operate at the second preset opening degree after the load and the compressor meet preset conditions specifically include: If the load operating temperature is greater than the preset temperature, and the timing starts after the compressor in the low-temperature refrigeration circuit is started, after a third preset time delay, the liquid injection valve operates at the second preset opening degree corresponding to the load operating temperature.

6. The method according to claim 1, characterized in that, After receiving the power-on signal, the step of controlling the main throttle valve to operate at the first anti-liquid hammer opening degree further includes: After the main throttle valve maintains the first anti-liquid hammer opening for a fourth preset time, the main throttle valve switches to feedback adjustment mode. In the feedback adjustment mode, the opening of the main throttle valve is adjusted according to the target physical parameters and the actual physical parameters, wherein the physical parameters include one or more of temperature, pressure, superheat and subcooling.

7. The method according to claim 1, characterized in that, After the main throttle valve operates at the second anti-liquid hammer opening for a first preset time, and then controls the compressor to stop, the method further includes: After the main throttle valve maintains the second anti-liquid hammer opening for a fifth preset time, the opening of the main throttle valve is switched to a preset balanced opening, which is greater than the first anti-liquid hammer opening and the second anti-liquid hammer opening. When the refrigeration cycle branch includes the hot gas bypass branch, the hot gas bypass valve operates at the fourth preset opening degree for the fifth preset duration and then closes.

8. The method according to claim 1, characterized in that, Before the step of controlling the main throttle valve to operate at a first preset opening, the method further includes: Upon receiving the power-on signal, the main throttle valve, the hot gas bypass valve, and / or the liquid injection valve perform a reset self-test step.

9. A refrigeration cycle system, characterized in that, The system includes a refrigeration main circuit and a controller. The refrigeration main circuit is equipped with a compressor, a condenser, a main circuit throttle valve, and a load evaporator, which are connected and closed in sequence. A refrigeration circulation branch is connected to the refrigeration main circuit. The refrigeration circulation branch includes a hot gas bypass branch and / or the liquid injection bypass branch. A hot gas bypass valve is provided on the hot gas bypass branch, and a liquid injection valve is provided on the liquid injection bypass branch. The controller performs valve control according to any one of claims 1 to 8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 8.

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