Evaporator outlet superheat degree control method and system, electronic equipment and storage medium

Abstract

The invention discloses an evaporator outlet superheat degree control method and system, electronic equipment and a storage medium. The method comprises the steps that after a first electronic expansion valve and a second electronic expansion valve are forced to operate based on a first preset opening degree, the outlet pressure of a condenser is obtained; when the outlet pressure of the condenser reaches the preset judgment pressure, the opening degree of the first electronic expansion valve and the opening degree of the second electronic expansion valve are adjusted based on a preset calibration table; the evaporator outlet temperature and the evaporator outlet pressure are obtained, and the evaporator outlet superheat degree is calculated according to the evaporator outlet temperature and the evaporator outlet pressure; and according to the evaporator outlet superheat degree, the opening degree of the first electronic expansion valve is adjusted based on a PID algorithm, so that the evaporator outlet superheat degree reaches the preset target superheat degree. According to the technical scheme provided by the embodiment of the invention, on the basis of the double-expansion-valve assembly, double optimization of the superheat degree reaction speed and precision of the refrigerating system is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration system control, and in particular, to a method, a system, an electronic device, and a storage medium for controlling the superheat at the evaporator outlet. Background Art

[0002] At present, the superheat regulation of refrigeration systems generally relies on fuzzy logic, which is a more advanced optimization method based on Proportional-Integral–Derivative (PID) regulation. The PID regulation of superheat requires feedback based on deviation. When the superheat is relatively high, fuzzy logic can often achieve good results, adjusting the expansion valve at a relatively fast speed to increase the flow rate so that the superheat can be quickly responded. When the flow rate is relatively large, due to the existence of latent heat, the superheat often does not drop below 0K, but remains between 0 and 1K, resulting in too small a deviation and the multiplication factor of fuzzy logic not being well utilized, causing the opening degree of the expansion valve to decrease too slowly, the flow rate to remain relatively large, the superheat of the system to be low, and the system to remain in a two-phase state for a long time, resulting in distorted measured heat transfer. Summary of the Invention

[0003] The present invention provides a method, a system, an electronic device, and a storage medium for controlling the superheat at the evaporator outlet to solve the problem of slow adjustment speed in existing superheat adjustment methods.

[0004] According to an aspect of the present invention, there is provided a method for controlling the superheat at the evaporator outlet, which is executed by a system for controlling the superheat at the evaporator outlet. The system includes a condenser, a pressure sensor, a first electronic expansion valve, a second electronic expansion valve, an evaporator, and a temperature sensor. The method includes:

[0005] After forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, obtain the condenser outlet pressure;

[0006] When the condenser outlet pressure reaches a preset determination pressure, adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table;

[0007] Obtain the evaporator outlet temperature and the evaporator outlet pressure, and calculate the superheat at the evaporator outlet according to the evaporator outlet temperature and the evaporator outlet pressure;

[0008] According to the superheat at the evaporator outlet, adjust the opening degree of the first electronic expansion valve based on the PID algorithm so that the superheat at the evaporator outlet reaches a preset target superheat.

[0009] Optionally, the preset determination pressure includes a first preset determination pressure and a second preset determination pressure;

[0010] When the condenser outlet pressure reaches the preset determination pressure, adjusting the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table includes:

[0011] When the condenser outlet pressure reaches the first preset determination pressure, adjust the opening degree of the second electronic expansion valve to a second preset opening degree based on the preset calibration table;

[0012] When the condenser outlet pressure reaches the second preset determination pressure, adjust the opening degree of the first electronic expansion valve to a third preset opening degree based on the preset calibration table.

[0013] Optionally, after the forced first electronic expansion valve and the second electronic expansion valve operate based on the first preset opening degree and the condenser outlet pressure is obtained, it further includes;

[0014] Obtain the rotational speed of the condenser fan;

[0015] According to the condenser outlet pressure, control the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure.

[0016] Optionally, the controlling the rotational speed of the condenser fan based on the PID algorithm according to the condenser outlet pressure so that the condenser outlet pressure reaches the preset determination pressure includes;

[0017] When the condenser outlet pressure is greater than the preset determination pressure, calculate the pressure deviation;

[0018] According to the pressure deviation, increase the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure;

[0019] Or, when the condenser outlet pressure is less than the preset determination pressure, calculate the pressure deviation;

[0020] According to the pressure deviation, decrease the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure.

[0021] Optionally, the adjusting the opening degree of the first electronic expansion valve based on the PID algorithm according to the superheat degree at the evaporator outlet so that the superheat degree at the evaporator outlet reaches the preset target superheat degree includes:

[0022] When the superheat degree at the evaporator outlet is greater than the preset target superheat degree, calculate the superheat degree deviation;

[0023] According to the superheat degree deviation, increase the opening degree of the first electronic expansion valve based on the PID algorithm so that the superheat degree at the evaporator outlet reaches the preset target superheat degree;

[0024] Alternatively, when the superheat at the evaporator outlet is less than the preset target superheat, calculate the superheat deviation;

[0025] Based on the superheat deviation and the PID algorithm, reduce the opening degree of the first electronic expansion valve so that the superheat at the evaporator outlet reaches the preset target superheat.

[0026] According to another aspect of the present invention, there is provided a superheat control system for an evaporator outlet, including a condenser, a pressure sensor, a first electronic expansion valve, a second electronic expansion valve, an evaporator, and a temperature sensor;

[0027] The pressure sensor includes a first pressure sensor and a second pressure sensor;

[0028] The condenser, the first pressure sensor, the first electronic expansion valve, the evaporator, the second pressure sensor, and the temperature sensor are sequentially connected in series, and the second electronic expansion valve is connected in parallel with the first electronic expansion valve; the system further includes a controller;

[0029] The first pressure sensor is used to obtain the condenser outlet pressure after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree;

[0030] The controller is used to adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table when the condenser outlet pressure reaches a preset determination pressure;

[0031] The temperature sensor and the second pressure sensor are respectively used to obtain the evaporator outlet temperature and the evaporator outlet pressure, and the controller is further used to calculate the superheat at the evaporator outlet according to the evaporator outlet temperature and the evaporator outlet pressure;

[0032] The controller is further used to adjust the opening degree of the first electronic expansion valve based on the PID algorithm according to the superheat at the evaporator outlet so that the superheat at the evaporator outlet reaches the preset target superheat.

[0033] According to another aspect of the present invention, there is provided an electronic device, the electronic device includes:

[0034] At least one processor; and

[0035] A memory communicatively connected to the at least one processor; wherein,

[0036] The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the superheat control method for the evaporator outlet according to any embodiment of the present invention.

[0037] According to another aspect of the present invention, there is provided a computer-readable storage medium storing computer instructions for causing a processor to implement the evaporator outlet superheat control method according to any embodiment of the present invention when executed.

[0038] Embodiments of the present invention provide an evaporator outlet superheat control method, system, electronic device and storage medium. The method includes: after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, obtaining the condenser outlet pressure; when the condenser outlet pressure reaches a preset determination pressure, adjusting the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table; obtaining the evaporator outlet temperature and the evaporator outlet pressure, and calculating the evaporator outlet superheat according to the evaporator outlet temperature and the evaporator outlet pressure; adjusting the opening degree of the first electronic expansion valve based on the PID algorithm according to the evaporator outlet superheat so that the evaporator outlet superheat reaches a preset target superheat. The technical solution provided by the embodiments of the present invention is based on a dual expansion valve assembly. First, the first electronic expansion valve and the second electronic expansion valve are forced to operate based on a first preset opening degree, and the opening degrees of the first electronic expansion valve and the second electronic expansion valve are adjusted based on a preset calibration table, realizing a dual optimization of the superheat response speed and accuracy of the refrigeration system. On the basis of primary fuzzy regulation, both the regulation accuracy and the regulation speed are ensured, and it has strong applicability to refrigeration scenarios that pursue fast response. According to actual measurements, only using primary fuzzy logic regulation, the fastest superheat response time of the system is about 9 minutes. By adopting the technical solution provided by the embodiments of the present invention, the superheat control accuracy can be achieved ±1K, and the specified superheat within the range of 0-10K can be reached 180 seconds after startup.

[0039] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0041] Figure 1 It is a flowchart of an evaporator outlet superheat control method provided by an embodiment of the present invention;

[0042] Figure 2 It is a schematic structural diagram of an evaporator outlet superheat control system provided by an embodiment of the present invention;

[0043] Figure 3 This is a schematic structural diagram of another superheat control system at the evaporator outlet provided by an embodiment of the present invention;

[0044] Figure 4 This is a schematic structural diagram of an electronic device for a superheat control method at the evaporator outlet provided by an embodiment of the present invention. Detailed implementation manners

[0045] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units does not necessarily need to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these process, method, product or device.

[0047] Figure 1 This is a flowchart of a superheat control method at the evaporator outlet provided by an embodiment of the present invention. This embodiment is applicable to the situation of controlling the superheat at the evaporator outlet. This method can be executed by a superheat control system at the evaporator outlet. The superheat control system at the evaporator outlet can be implemented in the form of hardware and / or software, and the superheat control system at the evaporator outlet can be configured in any electronic device with communication functions. Figure 2 This is a schematic structural diagram of a superheat control system at the evaporator outlet provided by an embodiment of the present invention. Refer to Figure 2, the system includes a condenser COND, a pressure sensor, a first electronic expansion valve EEV1, a second electronic expansion valve EEV2, an evaporator EVP, and a temperature sensor TT; among them, the pressure sensor includes a first pressure sensor TP1 and a second pressure sensor TP2, and the condenser COND, the first pressure sensor TP1, the first electronic expansion valve EEV1, the evaporator EVP, the second pressure sensor TP2, and the temperature sensor TT are sequentially connected in series, and the second electronic expansion valve EEV2 is connected in parallel with the first electronic expansion valve EEV1. See Figure 1 , the method includes:

[0048] S110. After forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, obtain the condenser outlet pressure.

[0049] Among them, the first preset opening degree can be preset according to the maximum opening degree of the expansion valve. In the embodiment of the present invention, the first preset opening degree is set to 100%.

[0050] Specifically, when the refrigeration system is started up, the first electronic expansion valve and the second electronic expansion valve are forced to be kept at the maximum opening degree. After forcing the first electronic expansion valve and the second electronic expansion valve to operate based on the maximum opening degree, that is, the first preset opening degree, the condenser outlet pressure is obtained through the pressure sensor. Among them, when the refrigeration system is started up, forcing the expansion valve to be kept at the maximum opening degree can enable the refrigerant to enter components such as the evaporator at the maximum flow rate. This can accelerate the circulation speed of the refrigerant in the system and quickly establish the pressure required for normal operation in the system. Because the rapid establishment of the system pressure is crucial for the refrigeration system to reach a stable working state as soon as possible. Only after the system pressure is stable can each component work normally under appropriate pressure conditions to achieve functions such as refrigeration or heating. And the rapid establishment of the system pressure helps to shorten the start-up time of the refrigeration system. If the opening degree of the expansion valve is small, the refrigerant flow is limited, and the system pressure is established slowly, which will cause equipment such as compressors to operate at a low efficiency for a long time, not only increasing the start-up energy consumption but also possibly affecting the service life of the equipment. By forcing the expansion valve to open to the maximum opening degree, the system can quickly enter the normal working state and improve the overall start-up efficiency.

[0051] S120. When the condenser outlet pressure reaches the preset determination pressure, adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on the preset calibration table.

[0052] Among them, the preset determination pressure can be preset according to the pressure required for the normal operation of the refrigeration system combined with the empirical values obtained through multiple tests. The preset calibration table is a table containing the correspondence between the refrigeration load heat transfer quantity and the expansion valve opening degree, and it can be obtained by calibrating the expansion valve opening degree under different refrigeration load heat transfer quantities.

[0053] Specifically, when the condenser outlet pressure reaches the preset determination pressure, the opening degrees of the first electronic expansion valve and the second electronic expansion valve are adjusted according to the load heat transfer amount by querying a preset calibration table. Among them, the refrigeration load heat transfer amount can be calculated by detecting the outlet refrigerant enthalpy value and the inlet refrigerant enthalpy value of the measured component, calculating the enthalpy difference between the outlet refrigerant enthalpy value and the inlet refrigerant enthalpy value, and multiplying the enthalpy difference by the flow rate. The flow rate can be detected by a mass flowmeter.

[0054] Exemplarily, assume that the required pressure during the normal operation of the refrigeration system is 1700 kPa, and the preset determination pressures are 1450 kPa and 1550 kPa respectively. When the condenser outlet pressure reaches 1450 kPa, the opening degree of the second electronic expansion valve is adjusted to 0% according to the current load heat transfer amount by querying the preset calibration table; when the condenser outlet pressure reaches 1550 kPa, the opening degree of the first electronic expansion valve is adjusted to 80% according to the current load heat transfer amount by querying the preset calibration table.

[0055] S130. Obtain the evaporator outlet temperature and the evaporator outlet pressure, and calculate the evaporator outlet superheat degree according to the evaporator outlet temperature and the evaporator outlet pressure.

[0056] Specifically, the evaporator outlet temperature is obtained through a temperature sensor, the evaporator outlet pressure is obtained through a pressure sensor, the evaporator outlet saturation temperature is determined by querying the physical property table of the corresponding refrigerant according to the evaporator outlet pressure, and the difference obtained by subtracting the evaporator outlet saturation temperature from the evaporator outlet temperature is determined as the evaporator outlet superheat degree.

[0057] S140. Based on the evaporator outlet superheat degree and the PID algorithm, adjust the opening degree of the first electronic expansion valve so that the evaporator outlet superheat degree reaches the preset target superheat degree.

[0058] Among them, the preset target superheat degree can be preset according to user requirements.

[0059] Specifically, compare the superheat at the evaporator outlet with the preset target superheat, calculate the deviation between the two, and based on the deviation between the superheat at the evaporator outlet and the preset target superheat, adjust the opening degree of the first electronic expansion valve based on the PID algorithm so that the superheat at the evaporator outlet reaches the preset target superheat. For example, first, proportional adjustment: The proportional link adjusts the opening degree of the first electronic expansion valve proportionally according to the magnitude of the deviation. The larger the deviation, the stronger the proportional adjustment effect, and the greater the change in the opening degree of the first electronic expansion valve to quickly reduce the deviation. Integral adjustment: The integral link integrates the deviation. As time accumulates, the integral effect will gradually increase. It is mainly used to eliminate the steady-state error of the system so that the superheat at the evaporator outlet finally stabilizes near the preset target superheat. Differential adjustment: The differential link adjusts the opening degree of the first electronic expansion valve according to the rate of change of the deviation. When the deviation changes rapidly, the differential adjustment effect will act in advance to suppress the drastic change of the superheat and make the system have better dynamic response performance. Finally, based on the combined effects of the proportional, integral, and differential links, the PID algorithm calculates the value of the opening degree of the first electronic expansion valve that needs to be adjusted, thereby accurately adjusting the opening degree of the first electronic expansion valve and changing the refrigerant flow rate entering the evaporator. By continuously measuring the superheat at the evaporator outlet, calculating the deviation, performing PID adjustment, and adjusting the opening degree of the expansion valve, a closed-loop feedback control system is formed. Over time, the system will gradually adjust the superheat at the evaporator outlet to near the preset target superheat and maintain stability.

[0060] An embodiment of the present invention provides a method, a system, an electronic device, and a storage medium for controlling the superheat at the evaporator outlet. The method includes: after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, obtaining the condenser outlet pressure; when the condenser outlet pressure reaches a preset determination pressure, adjusting the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table; obtaining the evaporator outlet temperature and the evaporator outlet pressure, and calculating the superheat at the evaporator outlet according to the evaporator outlet temperature and the evaporator outlet pressure; and adjusting the opening degree of the first electronic expansion valve based on the PID algorithm according to the superheat at the evaporator outlet so that the superheat at the evaporator outlet reaches the preset target superheat. The technical solution provided by the embodiment of the present invention is based on a dual expansion valve assembly. First, force the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, and adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table to achieve double optimization of the reaction speed and accuracy of the superheat of the refrigeration system. On the basis of primary fuzzy adjustment, both the adjustment accuracy and the adjustment speed are ensured, which has strong applicability for refrigeration scenarios that require fast response. According to actual measurements, only using primary fuzzy logic adjustment, the fastest superheat response time of the system is about 9 minutes. By adopting the technical solution provided by the embodiment of the present invention, the superheat control accuracy can reach ±1K, and the specified superheat within the range of 0-10K can be achieved 180 seconds after startup.

[0061] In some other embodiments, optionally, the preset determination pressure includes a first preset determination pressure and a second preset determination pressure, and the first preset determination pressure is less than the second preset determination pressure; step S120 specifically includes:

[0062] When the condenser outlet pressure reaches the first preset determination pressure, based on the preset calibration table, adjust the opening degree of the second electronic expansion valve to the second preset opening degree; when the condenser outlet pressure reaches the second preset determination pressure, based on the preset calibration table, adjust the opening degree of the first electronic expansion valve to the third preset opening degree.

[0063] Specifically, when the refrigeration system is operating, the condenser outlet pressure is monitored in real time. When this pressure reaches the first preset determination pressure, according to the current heat exchange amount of the refrigeration load, by querying the preset calibration table, determine the opening degree value of the second electronic expansion valve corresponding to the heat exchange amount of the refrigeration load, and adjust the opening degree of the second electronic expansion valve to the second preset opening degree. The purpose of this is to control the flow rate and pressure of the refrigerant in the relevant pipelines by adjusting the opening degree of the second electronic expansion valve, so as to adapt to the current operating state of the refrigeration system and ensure that the system can operate stably and efficiently. Similarly, when the pressure reaches the second preset determination pressure, according to the current heat exchange amount of the refrigeration load, by querying the preset calibration table, determine the opening degree value of the first electronic expansion valve corresponding to the heat exchange amount of the refrigeration load, and adjust the opening degree of the first electronic expansion valve to the third preset opening degree. This operation is also to enable the refrigeration system to optimize the refrigerant flow distribution and system pressure by precisely controlling the opening degree of the first electronic expansion valve according to the current condenser outlet pressure state, and ensure the performance and stability of the refrigeration system.

[0064] Optionally, after step S110, it further includes;

[0065] Obtain the rotational speed of the condenser fan.

[0066] Specifically, the rotational speed of the condenser fan is controlled by the input power magnitude. The current rotational speed of the fan can be determined according to the input power. For example, by measuring or obtaining the input voltage and current of the fan, calculating the power value, and then referring to the power-rotational speed correspondence table provided by the fan manufacturer, the actual rotational speed of the fan at this moment can be determined. This control method enables the rotational speed of the condenser fan to be precisely controlled by adjusting the input power to adapt to different operating conditions of the refrigeration system and heat dissipation requirements.

[0067] Based on the PID algorithm, control the rotational speed of the condenser fan according to the condenser outlet pressure, so that the condenser outlet pressure reaches the preset determination pressure.

[0068] Optionally, according to the condenser outlet pressure, based on a PID algorithm, controlling the speed of the condenser fan so that the condenser outlet pressure reaches a preset determination pressure includes:

[0069] When the condenser outlet pressure is greater than the preset judgment pressure, the pressure deviation is calculated;

[0070] According to the pressure deviation, based on the PID algorithm, the speed of the condenser fan is increased so that the condenser outlet pressure reaches the preset judgment pressure; alternatively, when the condenser outlet pressure is lower than the preset judgment pressure, the pressure deviation is calculated; according to the pressure deviation, based on the PID algorithm, the speed of the condenser fan is reduced so that the condenser outlet pressure reaches the preset judgment pressure.

[0071] Specifically, the condenser outlet pressure is compared with the preset judgment pressure, the deviation between the two is calculated, and the speed of the condenser fan is adjusted according to the calculated deviation based on the PID algorithm. First, proportional regulation: The proportional link adjusts the fan speed proportionally according to the size of the deviation. If the deviation is large, the proportional regulation will cause the fan speed to change significantly to quickly reduce the deviation. Integral regulation: The integral link integrates the deviation, and the integral effect gradually increases with the accumulation of time. It is mainly used to eliminate the steady-state error of the system and ensure that the condenser outlet pressure is finally stabilized near the preset judgment pressure. Even when the pressure deviation is small, the integral regulation will continue to work, so that the fan speed is continuously adjusted until the pressure is stable. Differential regulation: The differential link adjusts the fan speed according to the rate of change of the deviation. When the deviation changes rapidly, the differential regulation will act in advance to suppress the drastic change of pressure, so that the system has better dynamic response performance. Finally, the PID algorithm calculates the fan speed value that needs to be adjusted according to the comprehensive effect of the three links of proportional, integral and differential, so as to accurately adjust the fan speed, change the heat dissipation effect of the condenser, and then affect the condenser outlet pressure. By continuously measuring the condenser outlet pressure, calculating the deviation, performing PID adjustment and adjusting the fan speed, a closed-loop feedback control system is formed. As time goes by, the system will gradually adjust the condenser outlet pressure to near the preset judgment pressure and keep it stable, so that the refrigeration system is in good operating condition.

[0072] In some other embodiments, optionally, step S140 specifically includes:

[0073] When the superheat at the evaporator outlet is greater than the preset target superheat, the superheat deviation is calculated; based on the superheat deviation, the opening of the first electronic expansion valve is increased based on the PID algorithm to make the superheat at the evaporator outlet reach the preset target superheat; or, when the superheat at the evaporator outlet is less than the preset target superheat, the superheat deviation is calculated; based on the superheat deviation, the opening of the first electronic expansion valve is reduced based on the PID algorithm to make the superheat at the evaporator outlet reach the preset target superheat.

[0074] Specifically, compare the superheat at the evaporator outlet with the preset target superheat, calculate the deviation between the two, and based on the deviation between the superheat at the evaporator outlet and the preset target superheat, adjust the opening of the first electronic expansion valve according to the PID algorithm to make the superheat at the evaporator outlet reach the preset target superheat. For example, first, proportional adjustment: The proportional link adjusts the opening of the first electronic expansion valve proportionally according to the magnitude of the deviation. The larger the deviation, the stronger the proportional adjustment effect, and the greater the change in the opening of the first electronic expansion valve to quickly reduce the deviation. Integral adjustment: The integral link integrates the deviation. As time accumulates, the integral effect will gradually increase. It is mainly used to eliminate the steady-state error of the system so that the superheat at the evaporator outlet finally stabilizes near the preset target superheat. Differential adjustment: The differential link adjusts the opening of the first electronic expansion valve according to the rate of change of the deviation. When the deviation changes rapidly, the differential adjustment effect will act in advance to suppress the drastic change of the superheat and make the system have better dynamic response performance. Finally, the PID algorithm calculates the value of the opening of the first electronic expansion valve that needs to be adjusted based on the combined action of the proportional, integral, and differential links, thereby accurately adjusting the opening of the first electronic expansion valve and changing the refrigerant flow rate entering the evaporator. By continuously measuring the superheat at the evaporator outlet, calculating the deviation, performing PID adjustment, and adjusting the expansion valve opening, a closed-loop feedback control system is formed. Over time, the system will gradually adjust the superheat at the evaporator outlet to near the preset target superheat and maintain stability.

[0075] The technical solution provided by the embodiment of the present invention is based on a dual expansion valve assembly. By regulating the opening of the expansion valve, it realizes the dual optimization of the reaction speed and accuracy of the superheat of the refrigeration system, improving the regulation speed while ensuring the regulation accuracy.

[0076] Figure 3 A schematic structural diagram of another evaporator outlet superheat control system provided by the embodiment of the present invention is shown in Figure 3 , the system includes a condenser COND, a pressure sensor, a first electronic expansion valve EEV1, a second electronic expansion valve EEV2, an evaporator EVP, and a temperature sensor TT; wherein, the pressure sensor includes a first pressure sensor TP1 and a second pressure sensor TP2, and the condenser COND, the first pressure sensor TP1, the first electronic expansion valve EEV1, the evaporator EVP, the second pressure sensor TP2, and the temperature sensor TT are connected in sequence. The second electronic expansion valve EEV2 is connected in parallel with the first electronic expansion valve EEV1. The system further includes a controller 110, and the controller 110 is respectively connected to the condenser COND, the first pressure sensor TP1, the first electronic expansion valve EEV1, the second electronic expansion valve EEV2, the evaporator EVP, the second pressure sensor TP2, and the temperature sensor TT.

[0077] The first pressure sensor TP1 is used to obtain the condenser outlet pressure after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree.

[0078] The controller 110 is used to adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table when the condenser outlet pressure reaches a preset determination pressure.

[0079] The temperature sensor TT and the second pressure sensor TP2 are respectively used to obtain the evaporator outlet temperature and the evaporator outlet pressure, and the controller 110 is further used to calculate the evaporator outlet superheat degree according to the evaporator outlet temperature and the evaporator outlet pressure.

[0080] The controller 110 is further used to adjust the opening degree of the first electronic expansion valve based on the PID algorithm according to the evaporator outlet superheat degree, so that the evaporator outlet superheat degree reaches a preset target superheat degree.

[0081] The evaporator outlet superheat degree control system provided by the embodiments of the present invention can execute the evaporator outlet superheat degree control method provided by any embodiment of the present invention, and has the corresponding functional modules and beneficial effects for executing the method.

[0082] Figure 4 It is a schematic structural diagram of an electronic device for an evaporator outlet superheat degree control method provided by an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as, laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as, personal digital processors, cellular phones, smart phones, wearable devices (such as helmets, glasses, watches, etc.) and other similar computing devices. The components shown herein, their connections and relationships, and their functions are only examples and are not intended to limit the implementation of the present invention described and / or claimed herein.

[0083] As Figure 4 shown, the electronic device 10 includes at least one processor 11, and a memory communicatively connected to at least one processor 11, such as a read-only memory (ROM) 12, a random access memory (RAM) 13, etc. Among them, the memory stores a computer program executable by at least one processor, and the processor 11 can execute various appropriate actions and processes according to the computer program stored in the read-only memory (ROM) 12 or the computer program loaded from the storage unit 18 into the random access memory (RAM) 13. In the RAM 13, various programs and data required for the operation of the electronic device 10 can also be stored. The processor 11, the ROM 12, and the RAM 13 are connected to each other through a bus 14. The input / output (I / O) interface 15 is also connected to the bus 14.

[0084] Multiple components in the electronic device 10 are connected to the I / O interface 15, including: an input unit 16, such as a keyboard, a mouse, etc.; an output unit 17, such as various types of displays, speakers, etc.; a storage unit 18, such as a disk, an optical disc, etc.; and a communication unit 19, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 19 allows the electronic device 10 to exchange information / data with other devices through a computer network such as the Internet and / or various telecommunication networks.

[0085] The processor 11 can be various general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of the processor 11 include but are not limited to a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any suitable processor, controller, microcontroller, etc. The processor 11 executes the various methods and processes described above, such as a method for controlling the superheat at the evaporator outlet.

[0086] In some embodiments, the method for controlling the superheat at the evaporator outlet can be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as the storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed onto the electronic device 10 via the ROM 12 and / or the communication unit 19. When the computer program is loaded into the RAM 13 and executed by the processor 11, one or more steps of the method for controlling the superheat at the evaporator outlet described above can be executed. Alternatively, in other embodiments, the processor 11 can be configured to execute the method for controlling the superheat at the evaporator outlet in any other suitable manner (e.g., by means of firmware).

[0087] The various embodiments of the systems and techniques described above in this article can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SOCs), complex programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include: being implemented in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which can be a special-purpose or general-purpose programmable processor, and can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit the data and instructions to the storage system, the at least one input device, and the at least one output device.

[0088] A computer program for implementing the method of the present invention may be written in any combination of one or more programming languages. These computer programs can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowchart and / or block diagram to be implemented. The computer programs may be executed entirely on the machine, partly on the machine, as a stand-alone software package partly on the machine and partly on a remote machine, or entirely on a remote machine or server.

[0089] In the context of the present invention, a computer-readable storage medium may be a tangible medium that can contain or store a computer program for use by or in connection with an instruction execution system, apparatus, or device. The computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, the computer-readable storage medium may be a machine-readable signal medium. More specific examples of the machine-readable storage medium would include an electrical connection based on one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0090] In order to provide interaction with a user, the systems and techniques described herein may be implemented on an electronic device having: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and a pointing device (e.g., a mouse or a trackball) by which the user can provide input to the electronic device. Other kinds of devices may also be used to provide interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user may be received in any form (including acoustic input, voice input, or tactile input).

[0091] The systems and techniques described herein can be implemented in a computing system including backend components (e.g., as a data server), or a computing system including middleware components (e.g., an application server), or a computing system including frontend components (e.g., a user computer having a graphical user interface or a web browser through which a user can interact with an implementation of the systems and techniques described herein), or a computing system including any combination of such backend components, middleware components, or frontend components. The components of the system can be interconnected with each other by digital data communication in any form or medium (e.g., a communication network). Examples of communication networks include: local area network (LAN), wide area network (WAN), blockchain network, and the Internet.

[0092] A computing system can include a client and a server. The client and the server are generally remote from each other and typically interact through a communication network. The client-server relationship is created by computer programs running on respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or a cloud host, which is a host product in the cloud computing service system and solves the defects of difficult management and weak business scalability existing in traditional physical hosts and VPS services.

[0093] It should be understood that various forms of the processes shown above can be used, steps can be reordered, added, or deleted. For example, the steps recited in the present invention can be executed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0094] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for controlling the superheat at the evaporator outlet, characterized in that, Executed by an evaporator outlet superheat control system, the system includes a condenser, a pressure sensor, a first electronic expansion valve, a second electronic expansion valve, an evaporator, and a temperature sensor; the method includes: After forcing the first electronic expansion valve and the second electronic expansion valve to operate based on a first preset opening degree, obtain the condenser outlet pressure; When the condenser outlet pressure reaches a preset determination pressure, adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table; Obtain the evaporator outlet temperature and the evaporator outlet pressure, and calculate the evaporator outlet superheat according to the evaporator outlet temperature and the evaporator outlet pressure; According to the evaporator outlet superheat, adjust the opening degree of the first electronic expansion valve based on the PID algorithm so that the evaporator outlet superheat reaches a preset target superheat.

2. The method according to claim 1, characterized in that, The preset determination pressure includes a first preset determination pressure and a second preset determination pressure; The step of when the condenser outlet pressure reaches the preset determination pressure, adjusting the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on the preset calibration table includes: When the condenser outlet pressure reaches the first preset determination pressure, adjust the opening degree of the second electronic expansion valve to reach a second preset opening degree based on the preset calibration table; When the condenser outlet pressure reaches the second preset determination pressure, adjust the opening degree of the first electronic expansion valve to reach a third preset opening degree based on the preset calibration table.

3. The method according to claim 1, wherein After obtaining the condenser outlet pressure after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on the first preset opening degree, it further includes; Obtain the rotational speed of the condenser fan; According to the condenser outlet pressure, control the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure.

4. The method according to claim 3, wherein The step of according to the condenser outlet pressure, controlling the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure includes; When the condenser outlet pressure is greater than the preset determination pressure, calculate the pressure deviation; According to the pressure deviation, increase the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure; Or, when the condenser outlet pressure is less than the preset determination pressure, calculate the pressure deviation; According to the pressure deviation, decrease the rotational speed of the condenser fan based on the PID algorithm so that the condenser outlet pressure reaches the preset determination pressure.

5. The method according to claim 1, wherein The step of according to the evaporator outlet superheat, adjusting the opening degree of the first electronic expansion valve based on the PID algorithm so that the evaporator outlet superheat reaches the preset target superheat includes: When the evaporator outlet superheat is greater than the preset target superheat, calculate the superheat deviation; According to the superheat deviation, increase the opening degree of the first electronic expansion valve based on the PID algorithm so that the evaporator outlet superheat reaches the preset target superheat; Or, when the evaporator outlet superheat is less than the preset target superheat, calculate the superheat deviation; Based on the superheat deviation and the PID algorithm, reduce the opening degree of the first electronic expansion valve so that the superheat at the evaporator outlet reaches the preset target superheat.

6. An evaporator outlet superheat control system, characterized in that, It includes a condenser, a pressure sensor, a first electronic expansion valve, a second electronic expansion valve, an evaporator, and a temperature sensor; The pressure sensor includes a first pressure sensor and a second pressure sensor; The condenser, the first pressure sensor, the first electronic expansion valve, the evaporator, the second pressure sensor, and the temperature sensor are sequentially connected in series, and the second electronic expansion valve is connected in parallel with the first electronic expansion valve; the system further includes a controller; The first pressure sensor is used to obtain the condenser outlet pressure after forcing the first electronic expansion valve and the second electronic expansion valve to operate based on the first preset opening degree; The controller is used to adjust the opening degrees of the first electronic expansion valve and the second electronic expansion valve based on a preset calibration table when the condenser outlet pressure reaches the preset determination pressure; The temperature sensor and the second pressure sensor are respectively used to obtain the evaporator outlet temperature and the evaporator outlet pressure, and the controller is further used to calculate the superheat at the evaporator outlet according to the evaporator outlet temperature and the evaporator outlet pressure; The controller is further used to adjust the opening degree of the first electronic expansion valve based on the PID algorithm according to the superheat at the evaporator outlet so that the superheat at the evaporator outlet reaches the preset target superheat.

7. An electronic device, characterized in that, The electronic device includes: At least one processor; and A memory communicatively connected to the at least one processor; wherein, The memory stores a computer program executable by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the method for controlling the superheat at the evaporator outlet according to any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing a processor to implement the method for controlling the superheat at the evaporator outlet according to any one of claims 1-5 when executed.

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