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

Abstract

This invention discloses a linear cooling control method and an environmental test chamber for an environmental test chamber. The method includes determining the linear cooling rate of the environmental test chamber to be controlled; determining the linear target temperature at any time based on the linear cooling rate; obtaining the current temperature parameters of the environmental test chamber to be controlled; calculating the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed of the environmental test chamber to be controlled based on the linear target temperature and the current temperature parameters; and controlling the operation of the main circuit electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan speed of the environmental test chamber to be controlled based on the calculated opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed, thereby achieving linear cooling control of the environmental test chamber to be controlled. This application solves the technical problem of poor stability of the linear cooling temperature curve and poor system reliability in the linear cooling process of existing environmental test chambers by accurately calculating the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed, and using the calculation results to control the corresponding mechanisms.

Description

TECHNICAL FIELD

[0001] The embodiment of the present application relates to the technical field of temperature control, in particular to a linear cooling control method of an environmental test chamber and the environmental test chamber. BACKGROUND

[0002] At present, the linear cooling mostly uses a fixed-frequency compressor, and the cooling capacity is more than the compressor capacity in the early and middle stages of cooling, so the throttle valve adopts a multi-branch combination, and is switched on and off in different temperature intervals. When the throttle valves in different branches are opened, the system cooling capacity suddenly increases, resulting in a large fluctuation of the linear cooling temperature curve. At this time, the system uses heating to counteract again to reach the curve stability. If the selection or adjustment is unreasonable when the throttle valve is opened, the compressor suction may be liquid, affecting the system reliability. At the same time, the control of the fan is also crucial. When the fan air volume is small, the refrigerant in the evaporator cannot be completely evaporated, and when the fan air volume is large, the energy saving is poor.

[0003] In addition, in the early stage of cooling, the compressor suction temperature is high due to the high initial cooling temperature. In order to prevent the compressor motor from overheating, liquid needs to be sprayed into the compressor suction pipe to reduce the compressor suction temperature. However, when the liquid spraying amount control accuracy is poor, the compressor suction may be liquid, affecting the system operation reliability.

[0004] Therefore, optimizing the system control and operation in the linear cooling process is crucial for the linear cooling temperature curve stability, system simplification, system energy saving, and system operation reliability. SUMMARY

[0005] The embodiment of the present application provides a linear cooling control method of an environmental test chamber and the environmental test chamber, which solves the technical problem of poor linear cooling temperature curve stability and system operation reliability in the linear cooling process of the existing environmental test chamber.

[0006] The embodiment of the present application provides a linear cooling control method of an environmental test chamber, and the control method comprises:

[0007] Determine the linear cooling rate of the controlled environmental test chamber;

[0008] Determine the linear target temperature at any time based on the linear cooling rate;

[0009] Obtain the current temperature parameter of the controlled environmental test chamber, wherein the current temperature parameter comprises the chamber temperature, evaporator inlet temperature, evaporator outlet temperature, evaporator inlet air temperature, and compressor suction temperature of the controlled environmental test chamber;

[0010] calculating a main route electronic expansion valve opening degree, a liquid bypass electronic expansion valve opening degree and an evaporator fan rotating speed of the controlled environment test chamber based on the linear target temperature and the current temperature parameter respectively;

[0011] controlling the main route electronic expansion valve, the liquid bypass electronic expansion valve and the evaporator fan of the controlled environment test chamber based on the calculated main route electronic expansion valve opening degree, the liquid bypass electronic expansion valve opening degree and the evaporator fan rotating speed respectively, so as to realize linear cooling control of the controlled environment test chamber.

[0012] Further, the linear cooling rate of the controlled environment test chamber comprises:

[0013] acquiring preset temperature parameters of the controlled environment test chamber; wherein the preset temperature parameters at least include one of the following: a starting temperature, a final temperature and a total cooling time;

[0014] determining the linear cooling rate of the controlled environment test chamber by using the preset temperature parameters.

[0015] Further, the calculation of the main route electronic expansion valve opening degree of the controlled environment test chamber based on the linear target temperature and the current temperature parameter comprises:

[0016] based on the linear target temperature and the current temperature parameter, the main route electronic expansion valve opening degree is calculated by using a main route electronic expansion valve opening degree formula wherein Z is the main route electronic expansion valve opening degree, K1, I1 and D1 are respectively proportional-integral-derivative control proportional coefficient, integral coefficient and derivative coefficient of the main route electronic expansion valve, is a main route control deviation, τ is an arbitrary time within the total cooling time t, T is the temperature in the chamber, T0 is the starting temperature, T SV is the final temperature, p is a main route gain coefficient, V is the linear cooling rate, V C is a rate constant, T C is a temperature constant, T n is the linear target temperature, and n is a number corresponding to the linear target temperature and the corresponding time.

[0017] Further, before calculating the liquid bypass electronic expansion valve opening degree of the controlled environment test chamber based on the current temperature parameter, the control method further comprises:

[0018] establishing a first database between the evaporation temperature of the controlled environment test chamber, the temperature in the chamber and a first target value, wherein the first target value is a target value of the difference between the compressor suction temperature and the evaporator outlet temperature.

[0019] Furthermore, calculating the opening degree of the liquid bypass electronic expansion valve of the controlled environment test chamber based on the current temperature parameter includes:

[0020] Based on the current temperature parameters, the opening formula of the liquid bypass electronic expansion valve is used. Calculate the opening degree of the liquid bypass electronic expansion valve, where Q is the opening degree of the liquid bypass electronic expansion valve, and K2, I2, and D2 are the proportional coefficient, integral coefficient, and derivative coefficient of the proportional-integral-derivative control of the liquid bypass electronic expansion valve, respectively. Let τ be the liquid bypass control deviation, and τ be any moment within the total cooling time t. T a T is the suction temperature of the compressor. eo A is the outlet temperature of the evaporator. ij Here, i represents the first target value in the first database, j represents the number of the evaporation temperature, m represents the number of the chamber temperature, and m represents the liquid bypass gain coefficient. T is the temperature inside the chamber. Q This is the temperature constant of the electronic expansion valve.

[0021] Furthermore, after determining the linear target temperature at any given time based on the linear cooling rate, the control method further includes:

[0022] A second database is established between the linear target temperature, the linear cooling rate, and the second target value, wherein the second target value is a target value representing the difference between the evaporator inlet air temperature and the chamber temperature.

[0023] Furthermore, calculating the evaporator fan speed of the controlled environment test chamber based on the linear target temperature and the current temperature parameter includes:

[0024] Based on the linear target temperature and the current temperature parameters, the evaporator fan speed formula is used. Calculate the evaporator fan speed, where H is the evaporator fan speed, and K3, I3, and D3 are the proportional, integral, and derivative coefficients of the proportional-integral-derivative control of the evaporator fan speed, respectively. Let τ be the evaporator fan speed control deviation, and τ be any moment within the total cooling time t. T ai T is the evaporator inlet air temperature, B is the chamber temperature, and B is the inlet air temperature. s The second target value is the value in the second database, and s is the number of the linear target temperature.

[0025] Furthermore, determining the linear target temperature at any given time based on the linear cooling rate includes:

[0026] Based on the linear cooling rate, utilizing Determine the linear target temperature at any given time, where T n Let n be the linear target temperature, n be the number corresponding to the linear target temperature and any time τ, V be the linear cooling rate, and T0 be the initial temperature.

[0027] This invention also provides an environmental test chamber, which 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 described in any of the above embodiments.

[0028] 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.

[0029] The refrigeration system is installed inside the housing and includes a compressor, a condenser, an evaporator, an evaporator fan, a main electronic expansion valve, and a liquid bypass electronic expansion valve.

[0030] The main circuit electronic expansion valve, the evaporator, the compressor, and the condenser are connected in series to form a circuit. The liquid bypass electronic expansion valve is connected in parallel at both ends of the evaporator and the main circuit electronic expansion valve. The evaporator fan is located at the evaporator.

[0031] Furthermore, the sensor unit includes an internal temperature sensor, an evaporator inlet temperature sensor, an evaporator inlet air temperature sensor, an evaporator outlet temperature sensor, and a compressor suction air temperature sensor.

[0032] The evaporator inlet temperature sensor is located at the inlet of the evaporator; the evaporator air inlet temperature sensor is located at the air inlet of the evaporator; the evaporator outlet temperature sensor is located at the outlet of the evaporator; and the compressor suction temperature sensor is located at the compressor suction inlet.

[0033] The control unit includes a liquid bypass electronic expansion valve control module, a main circuit electronic expansion valve control module, and a data acquisition and calculation control module.

[0034] The data acquisition, calculation, and control module is electrically connected to the sensors in the sensor unit, the liquid bypass electronic expansion valve control module, and the main electronic expansion valve, respectively.

[0035] The liquid bypass electronic expansion valve control module is electrically connected to the liquid bypass electronic expansion valve.

[0036] The main circuit electronic expansion valve control module is electrically connected to the main circuit electronic expansion valve and the evaporator fan, respectively.

[0037] This invention discloses a linear cooling control method for an environmental test chamber and an environmental test chamber. The control method includes determining the linear cooling rate of the environmental test chamber to be controlled; determining the linear target temperature at any time based on the linear cooling rate; obtaining the current temperature parameters of the environmental test chamber to be controlled; calculating the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed of the environmental test chamber to be controlled based on the linear target temperature and the current temperature parameters; and controlling the operation of the main circuit electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan of the environmental test chamber to be controlled based on the calculated opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed, thereby realizing the 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 poor system reliability in the linear cooling process of existing environmental test chambers by accurately calculating the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass 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, improving the reliability of system operation, reducing system energy consumption, and simplifying the system control structure. Attached Figure Description

[0038] Figure 1 This is a flowchart of a linear cooling control method for an environmental test chamber provided in an embodiment of the present invention;

[0039] Figure 2 This is a structural diagram of an environmental test chamber provided in an embodiment of the present invention. Detailed Implementation

[0040] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0041] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this invention are used to distinguish different objects, not to limit a specific order. The various embodiments of this invention described below can be performed individually or in combination with each other; the embodiments of this invention do not impose specific limitations in this regard.

[0042] Figure 1 This is a flowchart of a linear cooling control method for an environmental test chamber provided in an embodiment of the present invention, as shown below. Figure 1As shown, the linear cooling control method of this environmental test chamber specifically includes the following steps:

[0043] S101, determine the linear cooling rate of the controlled environment test chamber.

[0044] Optionally, S101 specifically includes: acquiring preset temperature parameters of the controlled environment test chamber; wherein the preset temperature parameters include at least one of the following: initial temperature, final temperature, and total cooling time; and determining the linear cooling rate of the controlled environment test chamber using the preset temperature parameters.

[0045] Specifically, the environmental test chamber is equipped with a control system, which includes a display unit, a sensor unit, and a control unit. The control unit includes a liquid bypass electronic expansion valve control module, a main circuit electronic expansion valve control module, and a data acquisition and calculation control module. The data acquisition and calculation control module within the environmental test chamber can acquire the initial temperature T0 and the final temperature T of the test chamber. SV And the total cooling time t, then using the formula Determine the linear cooling rate of the controlled environment test chamber, where V is the linear cooling rate.

[0046] S102 determines the linear target temperature at any given time based on the linear cooling rate.

[0047] Optionally, S102 specifically includes:

[0048] Based on linear cooling rate utilization Determine the linear target temperature at any given time, where T n Let τ be the linear target temperature, n be the index corresponding to the linear target temperature at any time τ, V be the linear cooling rate, and T0 be the initial temperature.

[0049] S103, obtain the current temperature parameters of the controlled environment test chamber, including the internal temperature of the controlled environment test chamber, the evaporator inlet temperature, the evaporator outlet temperature, the evaporator inlet air temperature, and the compressor suction temperature.

[0050] Specifically, the control system of the environmental test chamber includes a sensor unit, which includes an internal temperature sensor, an evaporator inlet temperature sensor, an evaporator inlet air temperature sensor, an evaporator outlet temperature sensor, and a compressor suction temperature sensor, respectively used to acquire the internal temperature, evaporator inlet temperature, evaporator inlet air temperature, evaporator outlet temperature, and compressor suction temperature of the environmental test chamber under control.

[0051] S104, based on the linear target temperature and the current temperature parameters, calculate the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed of the test chamber under control.

[0052] Specifically, after obtaining the linear target temperature and the current temperature parameters, the opening degree or speed of the main circuit electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan are calculated using the linear target temperature, the current temperature parameters, the main circuit electronic expansion valve opening degree formula, the liquid bypass electronic expansion valve opening degree formula, and the evaporator fan speed formula.

[0053] S105 controls the operation of the main circuit electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan based on the calculated opening degree of the main circuit electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan speed, thereby achieving linear cooling control of the test chamber.

[0054] Specifically, by using the calculated opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the evaporator fan speed to control the main circuit electronic expansion valve, liquid bypass electronic expansion valve, and evaporator fan of the environmental test chamber under test, stable linear cooling control of the environmental test chamber under test can be achieved, and the risk of liquid carryover during compressor suction can be avoided.

[0055] This application solves the technical problems of poor stability of the linear cooling temperature curve and poor system reliability in the linear cooling process of existing environmental test chambers by accurately calculating the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass 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, improving the reliability of system operation, reducing system energy consumption, and simplifying the system control structure.

[0056] Based on the above technical solutions, S104, the calculation of the main electronic expansion valve opening of the controlled environment test chamber based on the linear target temperature and the current temperature parameters includes:

[0057] Based on the linear target temperature and current temperature parameters, the main circuit electronic expansion valve opening formula is used. Calculate the opening degree of the main circuit electronic expansion valve, where Z is the opening degree of the main circuit electronic expansion valve, and K1, I1, and D1 are the proportional coefficient, integral coefficient, and derivative coefficient of the proportional-integral-derivative control of the main circuit electronic expansion valve, respectively. Let τ be the main path control deviation, and τ be any moment within the total cooling time t. T is the internal temperature of the chamber, T0 is the initial temperature, and T SV For the final temperature, p is the main path gain coefficient. V is the linear cooling rate, V C T is the rate constant. C T is a temperature constant. n Let n be the linear target temperature, and n be the number corresponding to the linear target temperature and the corresponding time.

[0058] Based on the above technical solutions, before S104 calculates the opening degree of the liquid bypass electronic expansion valve of the test chamber under control based on the current temperature parameters, the control method also includes:

[0059] A first database is established to compare the evaporation temperature, the internal temperature of the test chamber, and the first target value of the controlled environment test chamber. The first target value is the target value of the difference between the compressor suction temperature and the evaporator outlet temperature.

[0060] Specifically, the first target value can be an empirically based calibration value, a theoretically analyzed value, or a value obtained from experimental measurements; no specific limitations are made here. Table 1 is a record table of the first database.

[0061] Table 1. Records of the First Database

[0062]

[0063] Based on the above technical solutions, S104, the calculation of the liquid bypass electronic expansion valve opening of the controlled environment test chamber based on the current temperature parameters includes:

[0064] Based on the current temperature parameters, the opening formula of the liquid bypass electronic expansion valve is used. Calculate the opening degree of the liquid bypass electronic expansion valve, where Q is the opening degree of the liquid bypass electronic expansion valve, and K2, I2, and D2 are the proportional coefficient, integral coefficient, and derivative coefficient of the proportional-integral-derivative control of the liquid bypass electronic expansion valve, respectively. Let τ be the liquid bypass control deviation, and τ be any moment within the total cooling time t. T a T is the compressor suction temperature. eo A is the evaporator outlet temperature. ij Here, i represents the first target value in the first database, j represents the number of the evaporation temperature, j represents the number of the chamber temperature, and m represents the liquid bypass gain coefficient. T is the temperature inside the chamber. Q This is the temperature constant of the electronic expansion valve.

[0065] Based on the above technical solutions, in S102, after determining the linear target temperature at any time based on the linear cooling rate, the control method further includes:

[0066] A second database is established to connect linear target temperature, linear cooling rate, and second target value, where the second target value is the target value of the difference between the evaporator inlet air temperature and the box temperature.

[0067] Specifically, the second target value can be an empirically based calibration value, a theoretically analyzed value, or a value obtained from experimental measurements; no specific limitations are made here. Table 2 is a record table of the second database.

[0068] Table 2. Records of the Second Database

[0069]

[0070] Based on the above technical solutions, S104, the calculation of the evaporator fan speed of the controlled environment test chamber based on the linear target temperature and the current temperature parameters includes:

[0071] Based on the linear target temperature and the current temperature parameters, the evaporator fan speed formula is used. Calculate the evaporator fan speed, where H is the evaporator fan speed, and K3, I3, and D3 are the proportional, integral, and derivative coefficients of the proportional-integral-derivative control of the evaporator fan speed, respectively. Let τ be the evaporator fan speed control deviation, and τ be any moment within the total cooling time t. T ai T is the evaporator inlet air temperature, B is the chamber internal temperature, and T is the inlet air temperature. s s represents the second target value in the second database, and s is the number of the linear target temperature.

[0072] Figure 2 This is a structural diagram of an environmental test chamber provided in an embodiment of the present invention.

[0073] The environmental test chamber includes a chamber body, a control system, and a refrigeration system. The control system executes the linear cooling control method of the environmental test chamber in any of the above embodiments.

[0074] 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.

[0075] The refrigeration system is located inside the cabinet and includes a compressor 1, a condenser 2, an evaporator 3, an evaporator fan 4, a main electronic expansion valve 5, and a liquid bypass electronic expansion valve 6.

[0076] like Figure 2 As shown, the main circuit electronic expansion valve 5, evaporator 3, compressor 1 and condenser 2 are connected in series to form a circuit. The liquid bypass electronic expansion valve 6 is connected in parallel at both ends of the evaporator 3 and the main circuit electronic expansion valve 5. The evaporator fan 4 is located at the evaporator.

[0077] Optionally, the sensor unit includes an internal temperature sensor 7, an evaporator inlet temperature sensor 8, an evaporator inlet air temperature sensor 9, an evaporator outlet temperature sensor 10, and a compressor suction temperature sensor 11; the evaporator inlet temperature sensor 8 is located at the inlet of the evaporator 3; the evaporator inlet air temperature sensor 9 is located at the air inlet of the evaporator 3; the evaporator outlet temperature sensor 10 is located at the outlet of the evaporator 3; and the compressor suction temperature sensor 11 is located at the suction port of the compressor 1.

[0078] The control unit includes a liquid bypass electronic expansion valve control module 12, a main circuit electronic expansion valve control module 13, and a data acquisition and calculation control module 14. The data acquisition and calculation control module 14 is electrically connected to the sensor in the sensor unit, the liquid bypass electronic expansion valve control module 12, and the main circuit electronic expansion valve control module 13, respectively. The liquid bypass electronic expansion valve control module 12 is electrically connected to the liquid bypass electronic expansion valve 6. The main circuit electronic expansion valve control module 13 is electrically connected to the main circuit electronic expansion valve 5 and the evaporator fan 4, respectively.

[0079] Specifically, the data acquisition and calculation control module 14 is used to determine the linear cooling rate of the environmental test chamber; determine the linear target temperature at any time based on the linear cooling rate; acquire the current temperature parameters of the environmental test chamber through various sensors; calculate the opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the speed of the evaporator fan based on the linear target temperature and the current temperature parameters, and then generate corresponding control commands based on the calculated opening degree of the main circuit electronic expansion valve, the opening degree of the liquid bypass electronic expansion valve, and the speed of the evaporator fan, and transmit the corresponding control commands to the liquid bypass electronic expansion valve control module 12 and the main circuit electronic expansion valve control module 13, so that the liquid bypass electronic expansion valve control module 12 and the main circuit electronic expansion valve control module 13 control the main circuit electronic expansion valve 5, the liquid bypass electronic expansion valve 6, and the evaporator fan 4 of the environmental test chamber to perform corresponding actions, thereby realizing the linear cooling control of the environmental test chamber.

[0080] 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.

[0081] In the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0082] Finally, it should be noted that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A linear cooling control method of an environmental test chamber, characterized by, The control method comprises: determining a linear cooling rate of the controlled environment test chamber; determining a linear target temperature at any time based on the linear cooling rate; obtaining a current temperature parameter of the controlled environment test chamber, wherein the current temperature parameter comprises an internal temperature of the controlled environment test chamber, an evaporator inlet temperature, an evaporator outlet temperature, an evaporator inlet air temperature, and a compressor suction temperature; calculating a main route electronic expansion valve opening degree, a liquid bypass electronic expansion valve opening degree, and an evaporator fan speed of the controlled environment test chamber based on the linear target temperature and the current temperature parameter, respectively; controlling the main route electronic expansion valve, the liquid bypass electronic expansion valve, and the evaporator fan of the controlled environment test chamber based on the calculated main route electronic expansion valve opening degree, the liquid bypass electronic expansion valve opening degree, and the evaporator fan speed, respectively, to realize linear cooling control of the controlled environment test chamber; calculating the main route electronic expansion valve opening degree of the controlled environment test chamber based on the linear target temperature and the current temperature parameter comprises: based on the linear target temperature and the current temperature parameter, using a main circuit electronic expansion valve opening degree formula calculating the main circuit electronic expansion valve opening degree, wherein Z is the main circuit electronic expansion valve opening degree, K1, I1, and D1 are respectively the proportional coefficient, integral coefficient, and differential coefficient of proportional-integral-differential control of the main circuit electronic expansion valve, is the main circuit control deviation, τ is the total cooling time t at any time, , T is the temperature in the box, T0 is the initial temperature, T SV is the final temperature, p is the main circuit gain coefficient, , V is the linear cooling rate, V C is the rate constant, T C is the temperature constant, T n is the linear target temperature, n is the number corresponding to the linear target temperature and the corresponding time. calculating the liquid bypass electronic expansion valve opening degree of the controlled environment test chamber based on the current temperature parameter comprises: based on the current temperature parameter, using a liquid bypass electronic expansion valve opening degree formula calculating the liquid bypass electronic expansion valve opening degree, wherein Q is the liquid bypass electronic expansion valve opening degree, K2, I2, D2 are respectively the proportional coefficient, integral coefficient, differential coefficient of proportional-integral-differential control of the liquid bypass electronic expansion valve, is the liquid bypass control deviation, τ is the total cooling time t at any time, , T a is the compressor suction temperature, T eo is the evaporator outlet temperature, A ij is the first target value in the first database, i is the number of evaporation temperature, j is the number of the box temperature, m is the liquid bypass gain coefficient, , T is the box temperature, T Q is the electronic expansion valve temperature constant.

2. The linear cooling control method of the environmental test chamber according to claim 1, characterized by, determining a linear cooling rate of the controlled environment test chamber comprises: obtaining a preset temperature parameter of the controlled environment test chamber, wherein the preset temperature parameter comprises at least one of a starting temperature, an ending temperature, and a total cooling time; determining the linear cooling rate of the controlled environment test chamber using the preset temperature parameter.

3. The linearly decreasing temperature control method of an environmental test chamber according to claim 1, characterized by, Before calculating the liquid bypass electronic expansion valve opening degree of the controlled environment test chamber based on the current temperature parameter, the control method further comprises: establishing a first database between an evaporating temperature of the controlled environment test chamber, the internal temperature, and a first target value, wherein the first target value is a target value of the difference between the compressor suction temperature and the evaporator outlet temperature.

4. The linearly decreasing temperature control method of an environmental test chamber according to claim 1, characterized by, After determining the linear target temperature at any time based on the linear cooling rate, the control method further comprises: establishing a second database between the linear target temperature, the linear cooling rate, and a second target value, wherein the second target value is a target value of the difference between the evaporator inlet air temperature and the internal temperature.

5. The linearly decreasing temperature control method of an environmental test chamber according to claim 4, wherein, calculating the evaporator fan speed of the controlled environment test chamber based on the linear target temperature and the current temperature parameter comprises: Based on the linear target temperature and the current temperature parameter, the evaporator fan speed is calculated by using an evaporator fan speed formula The evaporator fan speed is calculated, wherein H is the evaporator fan speed, K3, I3, D3 are respectively the proportional coefficient, integral coefficient, differential coefficient of the proportional-integral-differential control of the evaporator fan speed, The evaporator fan speed control deviation is calculated, τ is the total cooling time t at any time, , T ai The evaporator fan speed control deviation is calculated, τ is the total cooling time t at any time, s The second target value in the second database is calculated, s is the number of the linear target temperature.

6. The linearly decreasing temperature control method of an environmental test chamber according to claim 2, wherein, determining a linear target temperature at any time based on the linear cooling rate comprises: determining a linear target temperature at an arbitrary time point based on the linear cooling rate determining a linear target temperature at an arbitrary time point based on the linear cooling rate n wherein T is the linear target temperature, n is a number corresponding to the linear target temperature at an arbitrary time point τ, V is the linear cooling rate, and T0 is the initial temperature.

7. An environmental test chamber characterized by, The environmental test chamber comprises a chamber body, a control system, and a refrigeration system, and the control system executes the linear cooling control method of the environmental test chamber according to any one of claims 1-6; The control system comprises a display unit, a sensor unit, and a control unit, the sensor unit is arranged in the chamber body, the display unit is arranged on the surface of the chamber body, and the control unit is arranged in or outside the chamber body, and the display unit and the sensor unit are electrically connected with the control unit, respectively; The refrigeration system is arranged in the chamber body and comprises a compressor, a condenser, an evaporator, an evaporator fan, a main route electronic expansion valve, and a liquid bypass electronic expansion valve. The main route electronic expansion valve, the evaporator, the compressor and the condenser are sequentially connected in series to form a circuit, the liquid bypass electronic expansion valve is connected in parallel at both ends of the evaporator and the main route electronic expansion valve, and the evaporator fan is arranged at the evaporator.

8. Environmental test chamber according to claim 7, characterized in that The sensor unit comprises an in-box temperature sensor, an evaporator inlet temperature sensor, an evaporator inlet air temperature sensor, an evaporator outlet temperature sensor and a compressor suction temperature sensor. The evaporator inlet temperature sensor is arranged at the inlet of the evaporator, the evaporator inlet air temperature sensor is arranged at the air inlet of the evaporator, the evaporator outlet temperature sensor is arranged at the outlet of the evaporator, and the compressor suction temperature sensor is arranged at the suction port of the compressor. The control unit comprises a liquid bypass electronic expansion valve control module, a main route electronic expansion valve control module and a collection and calculation control module. The collection and calculation control module is electrically connected with the sensors in the sensor unit, the liquid bypass electronic expansion valve control module and the main route electronic expansion valve control module respectively. The liquid bypass electronic expansion valve control module is electrically connected with the liquid bypass electronic expansion valve. The main route electronic expansion valve control module is electrically connected with the main route electronic expansion valve and the evaporator fan respectively.

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