A linear cooling control method for an environmental test chamber and the environmental test chamber itself.

Abstract

This invention discloses a linear cooling control method for an environmental test chamber and an environmental test chamber itself. The method includes: acquiring the internal temperature, evaporator outlet temperature, and evaporator outlet pressure of the environmental test chamber; calculating the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the environmental test chamber based on the internal temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters; and controlling the operation of the pulse solenoid valve, electronic expansion valve, and evaporator fan of the environmental test chamber based on the calculated pulse solenoid valve opening degree, electronic expansion valve opening degree, and evaporator fan speed, thereby achieving linear cooling control of the environmental test chamber. The technical solution provided by this invention solves the technical problems of poor stability of the linear cooling temperature curve and small adaptability range of the cooling rate in the linear cooling process of existing environmental test chambers.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology, and in particular to a linear cooling control method for an environmental test chamber and the environmental test chamber itself. Background Technology

[0002] Currently, linear cooling systems mostly use fixed-frequency compressors. When a single electronic expansion valve is used as the expansion valve, the system structure is simple and the curve stability is good. However, due to the limitation of the electronic expansion valve's adjustment rate, it cannot achieve high-rate linear cooling. For applications requiring higher linear cooling rates, multi-channel combinations of expansion valves are generally used. In this case, the system structure is complex, the curve stability is poor, and it cannot cover low-rate linear cooling requirements. Furthermore, fan control is also crucial. If the fan airflow is too low, the refrigerant in the evaporator cannot evaporate completely; if the fan airflow is too high, energy efficiency is poor.

[0003] Therefore, optimizing the system control and operation during the linear cooling process is crucial for improving the stability of the linear cooling temperature curve, increasing the cooling rate adaptation range, simplifying the system, and reducing system operating energy consumption. Summary of the Invention

[0004] This invention provides a linear cooling control method and an environmental test chamber for an environmental test chamber, in order to solve the technical problems of poor stability of the linear cooling temperature curve and small adaptability range of the cooling rate in the linear cooling process of existing environmental test chambers.

[0005] According to one aspect of the present invention, a linear cooling control method for an environmental test chamber is provided, comprising:

[0006] Obtain the internal temperature, evaporator outlet temperature, and evaporator outlet pressure of the controlled environment test chamber;

[0007] Based on the temperature inside the chamber, the evaporator outlet temperature, the evaporator outlet pressure, and the preset temperature parameters, the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the controlled environment test chamber are calculated respectively.

[0008] Based on the calculated opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the speed of the evaporator fan, the pulse solenoid valve, the electronic expansion valve, and the evaporator fan of the test chamber under control are respectively controlled to achieve linear cooling control of the test chamber under control.

[0009] Optionally, the preset temperature parameters include: starting temperature, ending temperature, and total cooling time;

[0010] Based on the chamber temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters, the pulse solenoid valve opening, electronic expansion valve opening, and evaporator fan speed of the controlled environment test chamber are calculated, including:

[0011] The opening degree of the pulse solenoid valve is calculated based on the temperature inside the chamber, the initial temperature, the final temperature, and the total cooling time.

[0012] Calculate the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve;

[0013] The evaporator fan speed is calculated based on the evaporator outlet temperature, the evaporator outlet pressure, the preset evaporator superheat control target value, the opening degree of the pulse solenoid valve, and the opening degree of the electronic expansion valve.

[0014] Optionally, calculating the pulse solenoid valve opening based on the chamber temperature, the initial temperature, the final temperature, and the total cooling time includes:

[0015] Calculate the control deviation of the pulse solenoid valve based on the temperature inside the chamber, the initial temperature, the final temperature, and the total cooling time.

[0016] Calculate the pulse solenoid valve opening increment based on the pulse solenoid valve control deviation;

[0017] The opening degree of the pulse solenoid valve is calculated based on the opening degree increment of the pulse solenoid valve.

[0018] Optionally, calculating the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve includes:

[0019] Calculate the control deviation of the electronic expansion valve based on the opening degree of the pulse solenoid valve and the control deviation of the pulse solenoid valve;

[0020] Calculate the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve;

[0021] The opening degree of the electronic expansion valve is calculated based on the opening degree increment of the electronic expansion valve.

[0022] Optionally, calculating the evaporator fan speed based on the evaporator outlet temperature, the evaporator outlet pressure, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening includes:

[0023] Calculate the evaporator superheat based on the evaporator outlet temperature and the evaporator outlet pressure;

[0024] The evaporator fan control deviation is calculated based on the evaporator superheat, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening.

[0025] Calculate the evaporator fan speed increment based on the evaporator fan control deviation;

[0026] The evaporator fan speed is calculated based on the evaporator fan speed increment.

[0027] Optionally, calculating the control deviation of the pulse solenoid valve based on the chamber temperature, the initial temperature, the final temperature, and the total cooling time includes:

[0028] The control deviation of the pulse solenoid valve is calculated using the following formula:

[0029] In the formula, T0 is the initial temperature, T SV Let t be the final temperature, T be the total cooling time, T be the temperature inside the chamber, τ be any time within the total cooling time t, and e1(τ) be the control deviation of the pulse solenoid valve at time τ.

[0030] The calculation of the pulse solenoid valve opening increment based on the pulse solenoid valve control deviation includes:

[0031] The following formula is used to calculate the opening increment of the pulse solenoid valve:

[0032] ΔZ(τ)=P1·[e1(τ)-e1(τ-1)]+I1·e1(τ)+D1·[e1(τ)-2e1(τ-1)+e1(τ-2)]

[0033] T0≥T≥T SV , t≥τ≥0; where ΔZ(τ) is the pulse solenoid valve opening increment at time τ, P1 is the pulse solenoid valve control proportional coefficient, I1 is the pulse solenoid valve control integral coefficient, D1 is the pulse solenoid valve control differential coefficient, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0034] The step of calculating the pulse solenoid valve opening degree based on the pulse solenoid valve opening degree increment includes:

[0035] The opening degree of the pulse solenoid valve is calculated using the following formula:

[0036] Z(τ)=Z(τ-1)+ΔZ(τ); where Z(τ) is the opening degree of the pulse solenoid valve at time τ.

[0037] Optionally, calculating the electronic expansion valve control deviation based on the pulse solenoid valve opening degree and the pulse solenoid valve control deviation includes:

[0038] The control deviation of the electronic expansion valve is calculated using the following formula:

[0039] In the formula, e2(τ) is the electronic expansion valve control deviation at time τ;

[0040] The calculation of the electronic expansion valve opening increment based on the electronic expansion valve control deviation includes:

[0041] The opening increment of the electronic expansion valve is calculated using the following formula:

[0042] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+e2(τ-2)]

[0043] T0≥T≥T SV , t≥τ≥0; where ΔE(τ) is the opening increment of the electronic expansion valve at time τ, P2 is the proportional coefficient of the electronic expansion valve control, I2 is the integral coefficient of the electronic expansion valve control, D2 is the differential coefficient of the electronic expansion valve control, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0044] The step of calculating the electronic expansion valve opening based on the electronic expansion valve opening increment includes:

[0045] The opening degree of the electronic expansion valve is calculated using the following formula:

[0046] E(τ)=E(τ-1)+ΔE(τ); where E(τ) is the opening degree of the electronic expansion valve at time τ.

[0047] Optionally, calculating the evaporator fan control deviation based on the evaporator superheat, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening includes:

[0048] The evaporator fan control deviation is calculated using the following formula:

[0049] In the formula, e3(τ) is the evaporator fan control deviation at time (τ), k is the evaporator superheat, and k obj The preset target value for evaporator superheat control;

[0050] The calculation of the evaporator fan speed increment based on the evaporator fan control deviation includes:

[0051] The evaporator fan speed increment is calculated using the following formula:

[0052] ΔH(τ)=P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+e3(τ-2)]

[0053] T0≥T≥T SV, t≥τ≥0; where ΔH(τ) is the evaporator fan speed increment at time τ, P3 is the evaporator fan speed control proportional coefficient, I3 is the evaporator fan speed control integral coefficient, D3 is the evaporator fan speed control differential coefficient, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0054] The calculation of the evaporator fan speed based on the evaporator fan speed increment includes:

[0055] H(τ)=H(τ-1)+ΔH(τ); where H(τ) is the evaporator fan speed at time τ.

[0056] According to another aspect of the present invention, an environmental test chamber is provided, the environmental test chamber including a chamber body, a control system and a refrigeration system, wherein the control system executes the linear cooling control method of the environmental test chamber described in any of the above embodiments;

[0057] The control system includes a display unit, a sensor unit, and a control unit. The sensor unit is disposed inside the housing, the display unit is disposed on the surface of the housing, and the control unit is disposed inside or outside the housing. The display unit and the sensor unit are electrically connected to the control unit.

[0058] The refrigeration system is installed inside the housing and includes a compressor, a condenser, an evaporator, an evaporator fan, a pulse solenoid valve, and an electronic expansion valve; the evaporator, the electronic expansion valve, the pulse solenoid valve, the condenser, and the compressor are connected in series to form a circuit.

[0059] Optionally, the sensor unit includes an internal temperature sensor, an evaporator outlet temperature sensor, and an evaporator outlet pressure sensor; the evaporator outlet temperature sensor and the evaporator outlet pressure sensor are respectively located at the outlet of the evaporator.

[0060] The control unit includes an electronic expansion valve opening control module, a pulse solenoid valve opening control module, an evaporator fan speed control module, and a data acquisition and calculation control module.

[0061] The data acquisition and calculation control module is electrically connected to the internal temperature sensor; the electronic expansion valve opening control module is electrically connected to the electronic expansion valve; the pulse solenoid valve opening control module is electrically connected to the pulse solenoid valve; and the evaporator fan speed control module is electrically connected to the evaporator.

[0062] This invention provides a linear cooling control method for an environmental test chamber and an environmental test chamber itself. The method includes: acquiring the internal temperature, evaporator outlet temperature, and evaporator outlet pressure of the environmental test chamber to be controlled; calculating the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the environmental test chamber to be controlled based on the internal temperature, the evaporator outlet temperature, the evaporator outlet pressure, and preset temperature parameters; and controlling the pulse solenoid valve, the electronic expansion valve, and the evaporator fan speed of the environmental test chamber to be controlled based on the calculated pulse solenoid valve opening degree, electronic expansion valve opening degree, and evaporator fan speed, thereby achieving linear cooling control of the environmental test chamber to be controlled. This application solves the technical problems of poor stability of the linear cooling temperature curve and small cooling rate adaptation range in the linear cooling process of existing environmental test chambers by accurately calculating the pulse solenoid valve opening degree, the electronic expansion valve opening degree, and the evaporator fan speed, and using the calculation results to control the corresponding mechanisms. It achieves the technical effects of improving the stability of linear cooling control of the environmental test chamber, increasing the cooling rate adaptation range, reducing system operating energy consumption, and simplifying the system control structure.

[0063] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 A flowchart illustrating a linear cooling control method for an environmental test chamber provided in an embodiment of the present invention;

[0066] Figure 2 A flowchart of another linear cooling control method for an environmental test chamber provided in an embodiment of the present invention;

[0067] Figure 3 This is a structural schematic diagram of an environmental test chamber provided in an embodiment of the present invention. Detailed Implementation

[0068] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0069] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0070] Figure 1 A flowchart of a linear cooling control method for an environmental test chamber provided in an embodiment of the present invention is shown below. Figure 1 The linear cooling control method includes:

[0071] S110. Obtain the internal temperature of the controlled environment test chamber, the outlet temperature of the evaporator, and the outlet pressure of the evaporator.

[0072] An environmental test chamber is a device used to simulate various environmental conditions to test the performance and reliability of products or materials under different environments. Environmental test chambers can simulate various environmental factors, such as temperature, humidity, air pressure, light, and vibration. By placing products or materials inside the test chamber and testing them under set environmental conditions for a period of time, it is possible to understand the conditions the product might face in actual use environments, allowing for product improvement and optimization.

[0073] Specifically, the controlled environment test chamber is equipped with an internal temperature sensor, an evaporator outlet temperature sensor, and an evaporator outlet pressure sensor. The internal temperature, evaporator outlet temperature, and evaporator outlet pressure of the controlled environment test chamber can be obtained through these sensors.

[0074] S120. Based on the chamber temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters, calculate the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the controlled environment test chamber.

[0075] The preset temperature parameters can be set in advance according to the test requirements. The preset temperature parameters include at least one of the following: starting temperature, ending temperature, and total cooling time.

[0076] Specifically, after obtaining the internal temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters, the opening degree or speed of the pulse solenoid valve, electronic expansion valve, and evaporator fan are calculated respectively using the pulse solenoid valve opening degree formula, electronic expansion valve opening degree formula, and evaporator fan speed formula.

[0077] S130: Based on the calculated opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the speed of the evaporator fan, the pulse solenoid valve, the electronic expansion valve, and the evaporator fan of the controlled environment test chamber are controlled to achieve linear cooling control of the controlled environment test chamber.

[0078] Specifically, the pulse solenoid valve opening, electronic expansion valve opening, and evaporator fan speed of the environmental test chamber are controlled using calculated parameters. Since the calculation of the pulse solenoid valve opening involves the linear cooling rate, which characterizes the refrigerant flow rate, controlling these parameters achieves refrigerant flow control, thereby enabling stable linear cooling control of the environmental test chamber and increasing the adaptability of the cooling rate. Simultaneously, the evaporator fan speed is controlled according to changes in cooling capacity demand, effectively reducing fan energy consumption while ensuring system reliability.

[0079] The technical solution provided by this invention solves the technical problems of poor stability of the linear cooling temperature curve and small cooling rate adaptation range in the linear cooling process of existing environmental test chambers by accurately calculating the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the speed of the evaporator fan, and using the calculation results to control the corresponding mechanisms. It achieves the technical effects of improving the stability of the linear cooling control of the environmental test chamber, increasing the cooling rate adaptation range, reducing system operating energy consumption, and simplifying the system control structure.

[0080] Figure 2 This is a flowchart illustrating another linear cooling control method for an environmental test chamber provided by an embodiment of the present invention. This embodiment further refines the aforementioned embodiments based on the present invention. See also... Figure 2The linear cooling control method includes:

[0081] S210. Obtain the internal temperature of the controlled environment test chamber, the outlet temperature of the evaporator, and the outlet pressure of the evaporator.

[0082] S220. Calculate the opening degree of the pulse solenoid valve based on the temperature inside the chamber, the initial temperature, the final temperature, and the total cooling time.

[0083] Optionally, the pulse solenoid valve opening degree can be calculated based on the chamber temperature, initial temperature, final temperature, and total cooling time, including:

[0084] Calculate the control deviation of the pulse solenoid valve based on the internal temperature, initial temperature, final temperature, and total cooling time; calculate the pulse solenoid valve opening increment based on the control deviation; and calculate the pulse solenoid valve opening degree based on the pulse solenoid valve opening increment.

[0085] Specifically, the control deviation of the pulse solenoid valve is calculated using the following formula:

[0086] In the formula, T0 is the initial temperature, T SV Let t be the final temperature, T be the total cooling time, T be the temperature inside the chamber, τ be any time within the total cooling time t, and e1(τ) be the control deviation of the pulse solenoid valve at time τ.

[0087] The following formula is used to calculate the opening increment of the pulse solenoid valve:

[0088] ΔZ(τ)=P1·[e1(τ)-e1(τ-1)]+I1·e1(τ)+D1·[e1(τ)-2e1(τ-1)+e1(τ-2)]

[0089] T0≥T≥T SV , t≥τ≥0; where ΔZ(τ) is the pulse solenoid valve opening increment at time τ, P1 is the pulse solenoid valve control proportional coefficient, I1 is the pulse solenoid valve control integral coefficient, D1 is the pulse solenoid valve control differential coefficient, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0090] The opening degree of the pulse solenoid valve is calculated using the following formula:

[0091] Z(τ)=Z(τ-1)+ΔZ(τ); where Z(τ) is the opening degree of the pulse solenoid valve at time τ.

[0092] S230. Calculate the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve.

[0093] Optionally, the calculation of the electronic expansion valve opening based on the pulse solenoid valve opening includes:

[0094] Calculate the control deviation of the electronic expansion valve based on the opening degree and control deviation of the pulse solenoid valve; calculate the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve; calculate the opening degree of the electronic expansion valve based on the opening increment of the electronic expansion valve.

[0095] Specifically, the control deviation of the electronic expansion valve is calculated using the following formula:

[0096] In the formula, e2(τ) is the electronic expansion valve control deviation at time τ;

[0097] The opening increment of the electronic expansion valve is calculated using the following formula:

[0098] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+e2(τ-2)]

[0099] T0≥T≥T SV , t≥τ≥0; where ΔE(τ) is the opening increment of the electronic expansion valve at time τ, P2 is the proportional coefficient of the electronic expansion valve control, I2 is the integral coefficient of the electronic expansion valve control, D2 is the differential coefficient of the electronic expansion valve control, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0100] The opening degree of the electronic expansion valve is calculated using the following formula:

[0101] E(τ)=E(τ-1)+ΔE(τ); where E(τ) is the opening degree of the electronic expansion valve at time τ.

[0102] S240. Calculate the evaporator fan speed based on the evaporator outlet temperature, evaporator outlet pressure, preset evaporator superheat control target value, pulse solenoid valve opening degree, and electronic expansion valve opening degree.

[0103] Optionally, the evaporator fan speed is calculated based on the evaporator outlet temperature, evaporator outlet pressure, preset evaporator superheat control target value, pulse solenoid valve opening, and electronic expansion valve opening, including:

[0104] Calculate the evaporator superheat based on the evaporator outlet temperature and evaporator outlet pressure; calculate the evaporator fan control deviation based on the evaporator superheat, the preset evaporator superheat control target value, the opening degree of the pulse solenoid valve, and the opening degree of the electronic expansion valve; calculate the evaporator fan speed increment based on the evaporator fan control deviation; and calculate the evaporator fan speed based on the evaporator fan speed increment.

[0105] Specifically, evaporator superheat = evaporator outlet temperature - saturation temperature corresponding to evaporator outlet pressure. For example, assuming the evaporator outlet temperature is 10℃, by consulting the pressure-temperature conversion table, we find that the corresponding saturation temperature at the current evaporator outlet pressure is 5℃. Therefore, superheat = 10℃ - 5℃ = 5℃. The evaporator fan control deviation is calculated using the following formula:

[0106] In the formula, e3(τ) is the evaporator fan control deviation at time (τ), k is the evaporator superheat, and k obj This is the preset target value for evaporator superheat control.

[0107] The evaporator fan speed increment is calculated using the following formula:

[0108] ΔH(τ)=P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+e3(τ-2)]

[0109] T0≥T≥T SV , t≥τ≥0; where ΔH(τ) is the evaporator fan speed increment at time τ, P3 is the evaporator fan speed control proportional coefficient, I3 is the evaporator fan speed control integral coefficient, D3 is the evaporator fan speed control differential coefficient, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0110] The evaporator fan speed is calculated using the following formula:

[0111] H(τ)=H(τ-1)+ΔH(τ); where H(τ) is the evaporator fan speed at time τ.

[0112] S250 controls the pulse expansion valve, electronic expansion valve, and evaporator fan of the controlled environment test chamber based on the calculated opening degree of the pulse expansion valve, electronic expansion valve, and evaporator fan speed, thereby achieving linear cooling control of the controlled environment test chamber.

[0113] Figure 3 This is a structural schematic diagram of an environmental test chamber provided in an embodiment of the present invention. See also: Figure 3 The environmental test chamber includes a chamber body, a control system, and a refrigeration system. The control system executes the linear cooling control method for the environmental test chamber provided in any of the above embodiments.

[0114] The control system includes a display unit, a sensor unit, and a control unit. The sensor unit is located inside the enclosure, the display unit is located on the surface of the enclosure, and the control unit is located inside or outside the enclosure. The display unit and the sensor unit are electrically connected to the control unit.

[0115] The refrigeration system is installed inside the cabinet and includes compressor 2, condenser 3, evaporator fan 6, evaporator 7, pulse solenoid valve 4 and electronic expansion valve 5; evaporator 7, electronic expansion valve 5, pulse solenoid valve 4, condenser 3 and compressor 2 are connected in series to form a circuit.

[0116] Optionally, the sensor unit includes an internal temperature sensor 1, an evaporator outlet temperature sensor 8, and an evaporator outlet pressure sensor 9; the evaporator outlet temperature sensor 8 and the evaporator outlet pressure sensor 9 are respectively located at the outlet of the evaporator 7.

[0117] The control unit includes an electronic expansion valve opening control module 11, a pulse solenoid valve opening control module 12, an evaporator fan speed control module 10, and a data acquisition and calculation control module 13; the data acquisition and calculation control module 13 is electrically connected to the internal temperature sensor 1; the electronic expansion valve opening control module 11 is electrically connected to the electronic expansion valve 5; the pulse solenoid valve opening control module 12 is electrically connected to the pulse solenoid valve 4; and the evaporator fan speed control module 10 is electrically connected to the evaporator fan 6.

[0118] Specifically, the data acquisition and calculation control module 13 is used to calculate the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the environmental test chamber based on the chamber temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters. Then, based on the calculated opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed, corresponding control commands are generated and transmitted to the pulse solenoid valve opening degree control module 12, the electronic expansion valve opening degree control module 11, and the evaporator fan speed control module 10, respectively. This enables the pulse solenoid valve opening degree control module 12, the electronic expansion valve opening degree control module 11, and the evaporator fan speed control module 10 to control the pulse solenoid valve 4, the electronic expansion valve 5, and the evaporator fan 6 of the environmental test chamber to perform corresponding actions based on the control commands, thereby achieving linear cooling control of the environmental test chamber.

[0119] The environmental test chamber provided in this embodiment of the invention uses the linear cooling control method of the environmental test chamber in the above embodiment. Therefore, the environmental test chamber provided in this embodiment of the invention also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0120] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0121] The specific embodiments described above do not constitute a limitation on the scope of protection of this 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 principles of this invention should be included within the scope of protection of this invention.

Claims

1. A linear cooling control method for an environmental test chamber, characterized in that, include: Obtain the internal temperature, evaporator outlet temperature, and evaporator outlet pressure of the controlled environment test chamber; Based on the temperature inside the chamber, the evaporator outlet temperature, the evaporator outlet pressure, and the preset temperature parameters, the opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the evaporator fan speed of the controlled environment test chamber are calculated respectively. Based on the calculated opening degree of the pulse solenoid valve, the opening degree of the electronic expansion valve, and the speed of the evaporator fan, the pulse solenoid valve, the electronic expansion valve, and the evaporator fan of the test chamber under control are respectively controlled to achieve linear cooling control of the test chamber under control. The preset temperature parameters include: starting temperature, ending temperature, and total cooling time. Based on the chamber temperature, evaporator outlet temperature, evaporator outlet pressure, and preset temperature parameters, the pulse solenoid valve opening, electronic expansion valve opening, and evaporator fan speed of the controlled environment test chamber are calculated, including: The opening degree of the pulse solenoid valve is calculated based on the temperature inside the chamber, the initial temperature, the final temperature, and the total cooling time. Calculate the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve; The evaporator fan speed is calculated based on the evaporator outlet temperature, the evaporator outlet pressure, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening. The calculation of the pulse solenoid valve opening based on the chamber temperature, the initial temperature, the final temperature, and the total cooling time includes: Calculate the control deviation of the pulse solenoid valve based on the temperature inside the chamber, the initial temperature, the final temperature, and the total cooling time. Calculate the pulse solenoid valve opening increment based on the pulse solenoid valve control deviation; The opening degree of the pulse solenoid valve is calculated based on the pulse solenoid valve opening degree increment; The calculation of the electronic expansion valve opening based on the pulse solenoid valve opening includes: Calculate the control deviation of the electronic expansion valve based on the opening degree of the pulse solenoid valve and the control deviation of the pulse solenoid valve; Calculate the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve; The opening degree of the electronic expansion valve is calculated based on the opening degree increment of the electronic expansion valve. The calculation of the evaporator fan speed based on the evaporator outlet temperature, the evaporator outlet pressure, the preset evaporator superheat control target value, the opening degree of the pulse solenoid valve, and the opening degree of the electronic expansion valve includes: Calculate the evaporator superheat based on the evaporator outlet temperature and the evaporator outlet pressure; The evaporator fan control deviation is calculated based on the evaporator superheat, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening. Calculate the evaporator fan speed increment based on the evaporator fan control deviation; The evaporator fan speed is calculated based on the evaporator fan speed increment; The calculation of the pulse solenoid valve control deviation based on the chamber temperature, the initial temperature, the final temperature, and the total cooling time includes: The control deviation of the pulse solenoid valve is calculated using the following formula: In the formula, The starting temperature, The final temperature, Total cooling time The temperature inside the chamber. For any time within the total cooling time t, for The control deviation of the pulse solenoid valve at any given moment; The calculation of the pulse solenoid valve opening increment based on the pulse solenoid valve control deviation includes: The following formula is used to calculate the opening increment of the pulse solenoid valve: In the formula, for The instantaneous pulse solenoid valve opening increment. This refers to the proportional coefficient for pulse solenoid valve control. This represents the integral coefficient for pulse solenoid valve control. For the differential coefficient of the pulse solenoid valve control, , , They represent time, Time and time; The step of calculating the pulse solenoid valve opening degree based on the pulse solenoid valve opening degree increment includes: The opening degree of the pulse solenoid valve is calculated using the following formula: In the formula, for The opening degree of the pulse solenoid valve at any given moment; The calculation of the electronic expansion valve control deviation based on the pulse solenoid valve opening degree and the pulse solenoid valve control deviation includes: The control deviation of the electronic expansion valve is calculated using the following formula: In the formula, for The control deviation of the electronic expansion valve at any given moment; The calculation of the electronic expansion valve opening increment based on the electronic expansion valve control deviation includes: The opening increment of the electronic expansion valve is calculated using the following formula: In the formula, for The increment of the electronic expansion valve opening at any given time. This refers to the proportional control coefficient of the electronic expansion valve. This refers to the integral coefficient for electronic expansion valve control. The differential coefficient for electronic expansion valve control. , , They represent time, Time and time; The step of calculating the electronic expansion valve opening based on the electronic expansion valve opening increment includes: The opening degree of the electronic expansion valve is calculated using the following formula: In the formula, for The opening degree of the electronic expansion valve at any given time; The calculation of the evaporator fan control deviation based on the evaporator superheat, the preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening includes: The evaporator fan control deviation is calculated using the following formula: In the formula, for Evaporator fan control deviation at any given time For evaporator superheat, The preset target value for evaporator superheat control; The calculation of the evaporator fan speed increment based on the evaporator fan control deviation includes: The evaporator fan speed increment is calculated using the following formula: In the formula, for The instantaneous increase in evaporator fan speed. This is the proportional coefficient for controlling the evaporator fan speed. The integral coefficient for evaporator fan speed control. This is the differential coefficient for controlling the evaporator fan speed. , , They represent time, Time and time; The calculation of the evaporator fan speed based on the evaporator fan speed increment includes: In the formula, for The evaporator fan speed at any given time.

2. An environmental test chamber, characterized in that, The environmental test chamber includes a chamber body, a control system, and a refrigeration system. The control system executes the linear cooling control method for the environmental test chamber as described in claim 1. The control system includes a display unit, a sensor unit, and a control unit. The sensor unit is disposed inside the housing, the display unit is disposed on the surface of the housing, and the control unit is disposed inside or outside the housing. The display unit and the sensor unit are electrically connected to the control unit. The refrigeration system is installed inside the housing and includes a compressor, a condenser, an evaporator, an evaporator fan, a pulse solenoid valve, and an electronic expansion valve; the evaporator, the electronic expansion valve, the pulse solenoid valve, the condenser, and the compressor are connected in series to form a circuit.

3. The environmental test chamber according to claim 2, characterized in that, The sensor unit includes an internal temperature sensor, an evaporator outlet temperature sensor, and an evaporator outlet pressure sensor; the evaporator outlet temperature sensor and the evaporator outlet pressure sensor are respectively located at the outlet of the evaporator; The control unit includes an electronic expansion valve opening control module, a pulse solenoid valve opening control module, an evaporator fan speed control module, and a data acquisition and calculation control module. The data acquisition and calculation control module is electrically connected to the internal temperature sensor; the electronic expansion valve opening control module is electrically connected to the electronic expansion valve; the pulse solenoid valve opening control module is electrically connected to the pulse solenoid valve; and the evaporator fan speed control module is electrically connected to the evaporator.

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