A temperature control method and system for an environmental test chamber

Abstract

The application discloses a kind of environmental test chamber temperature control method and system.The method comprises: according to the final temperature of environmental test chamber and adjusting step value, determine the target temperature of current time;According to the actual temperature in chamber and target temperature, the opening of main road electromagnetic valve is controlled;According to the actual temperature in chamber, initial temperature and the temperature parameter of evaporator, the opening of gas bypass electromagnetic valve is controlled;According to the actual temperature in chamber, initial temperature, bypass temperature, the temperature parameter of evaporator and the temperature parameter of compressor, the opening of liquid bypass electromagnetic valve is controlled according to proportional integral differential control strategy, and return to execute according to the final temperature of environmental test chamber and adjusting step value determines the target temperature of current time step, until the actual temperature of environmental test chamber reaches final temperature.The scheme of the application can more accurately adjust the opening of gas bypass electromagnetic valve and liquid bypass electromagnetic valve, more accurately adjust the temperature of test chamber, can make that compressor oil return is smooth, reduce system energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental test chamber, and particularly relates to an environmental test chamber temperature control method and system. BACKGROUND

[0002] With the increasing progress of life and technology, the requirement for product reliability is higher and higher. In many fields, it is necessary to test the reliability of products or parts, material stress changes, changes in material properties, etc. during the process of decreasing from high temperature to low temperature for a certain time.

[0003] At present, linear cooling mostly uses a fixed-frequency compressor. The cooling capacity of the compressor is more than the cooling demand in the early and middle stages of cooling. In order to ensure the oil return reliability of the system, the flow rate of the refrigerant in the system pipeline needs to be maintained within a certain range, and the fixed-frequency compressor itself cannot adjust the cooling capacity of the compressor. Therefore, a heating offset method needs to be used, which will cause a large amount of waste of electric energy. Therefore, optimizing the system control and operation in the linear cooling process is crucial for system operation reliability and energy saving. SUMMARY

[0004] The present application provides an environmental test chamber temperature control method and system to realize more accurate control of the temperature of the environmental test chamber.

[0005] According to one aspect of the present application, an environmental test chamber temperature control method is provided, which is realized by an environmental test chamber temperature control system. The system includes a controller, a main circuit, a gas bypass and a liquid bypass. The main circuit includes a compressor, a condenser, a main circuit electromagnetic valve and an evaporator connected in series. The liquid bypass is connected between the inlet of the compressor and the outlet of the condenser, and includes a liquid bypass electromagnetic valve. The gas bypass is connected between the inlet of the compressor and the inlet of the condenser, and includes a gas bypass electromagnetic valve. The controller is connected with the main circuit electromagnetic valve, the liquid bypass electromagnetic valve and the gas bypass electromagnetic valve respectively. The method is executed by the controller. The method includes:

[0006] determining a target temperature at the current time according to the final temperature of the environmental test chamber and the adjustment step value; wherein the target temperature is less than the initial temperature of the environmental test chamber and greater than or equal to the final temperature;

[0007] controlling the opening degree of the main circuit electromagnetic valve according to the proportional-integral-derivative strategy according to the actual temperature in the chamber and the target temperature;

[0008] controlling the opening degree of the gas bypass electromagnetic valve according to the proportional-integral-derivative control strategy according to the actual temperature in the chamber, the initial temperature and the temperature parameter of the evaporator;

[0009] controlling the opening of the liquid bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on the actual temperature in the chamber, the initial temperature, bypass temperature, temperature parameters of the evaporator and temperature parameters of the compressor, and returning to performing the step of determining the target temperature at the current time according to the final temperature of the environmental test chamber and the adjustment step value until the actual temperature of the environmental test chamber reaches the final temperature.

[0010] Optionally, controlling the opening of the gas bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on the actual temperature in the chamber, the initial temperature and the temperature parameters of the evaporator, comprises:

[0011] controlling the opening of the gas bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on a first deviation value of the actual temperature in the chamber and the initial temperature, a second deviation value of the actual temperature in the chamber and the evaporator outlet temperature, a third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and a fourth deviation value of the actual temperature in the chamber and the evaporator inlet temperature;

[0012] controlling the opening of the liquid bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on the actual temperature in the chamber, the initial temperature, bypass temperature, temperature parameters of the evaporator and temperature parameters of the compressor, comprises:

[0013] controlling the opening of the liquid bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on the first deviation value, a fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, a sixth deviation value of the bypass temperature and the evaporator outlet temperature, and a seventh deviation value of the bypass temperature and the compressor suction temperature.

[0014] Optionally, after controlling the opening of the liquid bypass electromagnetic valve according to a proportional-integral-derivative control strategy based on the actual temperature in the chamber, the initial temperature, bypass temperature, temperature parameters of the evaporator and temperature parameters of the compressor, it further comprises:

[0015] when the opening of the liquid bypass electromagnetic valve is greater than a preset threshold value, correcting the opening of the gas bypass electromagnetic valve according to the opening of the liquid bypass electromagnetic valve.

[0016] Optionally, the step of correcting the opening of the gas bypass electromagnetic valve according to the opening of the liquid bypass electromagnetic valve, comprises:

[0017] determining a target correction coefficient according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening of the gas bypass electromagnetic valve and the opening of the liquid bypass electromagnetic valve;

[0018] The opening degree of the gas bypass electromagnetic valve is updated according to the product of the opening degree of the gas bypass electromagnetic valve and the target correction coefficient.

[0019] Optionally, the target correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve, including:

[0020] The first correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value and the sixth deviation value;

[0021] The second correction coefficient is determined according to the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve;

[0022] The maximum value between the first correction coefficient and the second correction coefficient is taken as the target correction coefficient.

[0023] Optionally, the opening degree of the gas bypass electromagnetic valve is controlled according to the first deviation value of the actual temperature in the box and the initial temperature, the second deviation value of the actual temperature in the box and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature, according to a proportional-integral-derivative control strategy, including:

[0024] The first adjustment value is the product of the first ratio of the second deviation value to the first deviation value, the second ratio of the third deviation value to the first deviation value, and the third ratio of the fourth deviation value to the first deviation value;

[0025] The first target control amount is the sum of the product of the first proportional coefficient and the first adjustment value, the product of the first integral coefficient and the integral value of the first adjustment value, and the product of the first derivative coefficient and the derivative value of the first adjustment value, so as to control the opening degree of the gas bypass electromagnetic valve according to the first target control amount.

[0026] Optionally, the opening degree of the liquid bypass electromagnetic valve is controlled according to the first deviation value, the fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, the sixth deviation value of the bypass temperature and the evaporator outlet temperature, and the seventh deviation value of the bypass temperature and the compressor suction temperature, according to a proportional-integral-derivative control strategy, including:

[0027] The second adjustment value is the ratio of the fifth deviation value to the first deviation value;

[0028] The third adjustment value is the ratio of the sixth deviation value to the seventh deviation value;

[0029] According to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to a proportional-integral-derivative control strategy.

[0030] Optionally, according to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to a proportional-integral-derivative control strategy, including:

[0031] A sum of a product of a second proportional coefficient and the second adjustment value, a product of a second integral coefficient and an integral value of the second adjustment value, and a product of a second derivative coefficient and a derivative value of the second adjustment value is taken as a first control quantity;

[0032] A sum of a product of a third proportional coefficient and the third adjustment value, a product of a third integral coefficient and an integral value of the third adjustment value, and a product of a third derivative coefficient and a derivative value of the third adjustment value is taken as a second control quantity;

[0033] A maximum value between the first control quantity and the second control quantity is taken as a second target control quantity, so as to control the opening of the liquid bypass electromagnetic valve according to the second target control quantity.

[0034] Optionally, according to the actual temperature in the chamber and the target temperature, the opening of the main circuit electromagnetic valve is controlled according to a proportional-integral-derivative control strategy, including:

[0035] A temperature adjustment time is calculated according to a difference between the initial temperature and the final temperature and a temperature change rate;

[0036] A fourth adjustment value is determined according to the actual temperature in the chamber, a product of the temperature change rate and a time difference value, and the final temperature; the time difference value is a difference between the temperature adjustment time and a current time;

[0037] A sum of a product of a fourth proportional coefficient and the fourth adjustment value, a product of a fourth integral coefficient and an integral value of the fourth adjustment value, and a product of a fourth derivative coefficient and a derivative value of the fourth adjustment value is taken as a third target control quantity, so as to control the opening of the main circuit electromagnetic valve according to the third target control quantity.

[0038] According to another aspect of the present application, there is provided an environmental test chamber temperature control system, the system comprising a controller, a main circuit, a gas bypass and a liquid bypass; the controller is configured to execute the environmental test chamber temperature control method according to any one of the embodiments of the present application.

[0039] The main circuit comprises a compressor, a condenser, a main circuit electromagnetic valve and an evaporator connected in series; the liquid bypass is connected between the inlet of the compressor and the outlet of the condenser, and comprises a liquid bypass electromagnetic valve; the gas bypass is connected between the inlet of the compressor and the inlet of the condenser, and comprises a gas bypass electromagnetic valve; the controller is connected with the main circuit electromagnetic valve, the liquid bypass electromagnetic valve and the gas bypass electromagnetic valve respectively.

[0040] Optionally, the system further comprises an in-chamber temperature sensor, a suction temperature sensor, a bypass temperature sensor, an evaporator inlet temperature sensor and an evaporator outlet temperature sensor;

[0041] The in-chamber temperature sensor is located in the test chamber, and is connected with the controller, and is used for detecting the actual temperature in the chamber and sending to the controller;

[0042] The suction temperature sensor is located at the inlet of the compressor, and is connected with the controller, and is used for detecting the suction temperature of the compressor and sending to the controller;

[0043] The bypass temperature sensor is located between the inlet of the compressor and the liquid bypass, and is connected with the controller, and is used for detecting the bypass temperature and sending to the controller;

[0044] The evaporator inlet temperature sensor is located at the inlet of the evaporator, and is connected with the controller, and is used for detecting the evaporator inlet temperature and sending to the controller;

[0045] The evaporator outlet temperature sensor is located at the outlet of the evaporator, and is connected with the controller, and is used for detecting the evaporator outlet temperature and sending to the controller.

[0046] The technical scheme of the embodiment of the present application realizes coupled calculation of refrigerant main flow, gas bypass flow and liquid bypass flow, can more accurately adjust the opening degree of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve, so as to more accurately adjust the temperature of the environmental test chamber. Moreover, the compressor oil return can be smoother, the risk of oil shortage of the compressor can be avoided, and the operation reliability of the environmental test chamber is improved. Through accurate control of the opening degree of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve, the opening degree of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve can be avoided to be too large, and the system energy consumption is reduced.

[0047] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0049] Figure 1 is a flow chart of an environmental test chamber temperature control method provided by an embodiment of the present application;

[0050] Figure 2 is a flow chart of another environmental test chamber temperature control method provided by an embodiment of the present application;

[0051] Figure 3 is a flow chart of another environmental test chamber temperature control method provided by an embodiment of the present application;

[0052] Figure 4 is a flow chart of another environmental test chamber temperature control method provided by an embodiment of the present application;

[0053] Figure 5 is a structural schematic diagram of an environmental test chamber temperature control system provided by an embodiment of the present application;

[0054] Figure 6 is a structural schematic diagram of another environmental test chamber temperature control system provided by an embodiment of the present application. Detailed Implementation

[0055] 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.

[0056] 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.

[0057] This invention provides a method for controlling the temperature of an environmental test chamber. This method is implemented by a temperature control system for the environmental test chamber, which includes a controller, a main circuit, a gas bypass, and a liquid bypass. The main circuit includes a compressor, a condenser, a main circuit solenoid valve, and an evaporator connected in series. The liquid bypass is connected between the compressor inlet and the condenser outlet and includes a liquid bypass solenoid valve. The gas bypass is connected between the compressor inlet and the condenser inlet and includes a gas bypass solenoid valve. The controller is connected to the main circuit solenoid valve, the liquid bypass solenoid valve, and the gas bypass solenoid valve. The environmental test chamber temperature control method is executed by the controller.

[0058] Specifically, the compressor can draw in superheated vapor, compressing the gaseous refrigerant into high-temperature, high-pressure gaseous refrigerant superheated vapor. This high-temperature, high-pressure gaseous refrigerant superheated vapor enters the condenser through the exhaust pipe, where it is condensed by the condenser and condenser fan into a normal-temperature, high-pressure liquid refrigerant. This normal-temperature, high-pressure liquid refrigerant then enters the evaporator, where it evaporates and vaporizes, absorbing heat and lowering the test chamber temperature. By setting up liquid and gas bypasses, the liquid and gas flow rates in the main circuit can be adjusted to prevent poor oil return from the compressor.

[0059] Figure 1 This is a flowchart of a temperature control method for an environmental test chamber provided in an embodiment of the present invention, for reference. Figure 1The temperature control method of the environmental test chamber comprises the following steps:

[0060] S110, determining a target temperature at the current time according to the final temperature of the environmental test chamber and an adjustment step value; wherein the target temperature is less than an initial temperature of the environmental test chamber and greater than or equal to the final temperature; wherein the initial temperature is the temperature of the environmental test chamber at the beginning of adjustment.

[0061] Specifically, when a device is tested by using the environmental test chamber, for example, linear cooling is performed, the final temperature and the cooling rate can be set, and the temperature of the environmental test chamber is adjusted for multiple times until the final temperature is reached. The target temperature is the target value of each adjustment, and the target temperature can be the sum of the final temperature and the adjustment step value. The adjustment step value is different at each adjustment, for example. The adjustment step value can be calculated according to the total adjustment time, the current time and the speed change rate. For example, the cooling rate is 0.5℃ / s, the total adjustment time is 10s, the final temperature is-20℃, and the current time is the 2nd second of adjustment, then the target temperature corresponding to the current time is 0.5x(10-2)-20=-16℃; the current time is the 4th second, then the target temperature corresponding to the current time is 0.5x(10-4)-20=-17℃, thereby realizing linear cooling.

[0062] S120, controlling the opening degree of the main electromagnetic valve according to the proportional-integral-derivative strategy according to the actual temperature in the chamber and the target temperature.

[0063] Specifically, by obtaining the actual temperature in the chamber, the difference between the actual temperature in the chamber and the target temperature at the current time is taken as a deviation value, and the control amount of the current adjustment is determined according to the proportional-integral-derivative strategy. The control amount is, for example, an opening degree adjustment amount, and the main electromagnetic valve is controlled according to the obtained control amount, so that the main electromagnetic valve reaches the opening degree corresponding to the target temperature, thereby adjusting the refrigerant flow of the main circuit and facilitating the adjustment of the temperature of the environmental test chamber to the target temperature.

[0064] S130, controlling the opening degree of the gas bypass electromagnetic valve according to the proportional-integral-derivative control strategy according to the actual temperature in the chamber, the initial temperature and the temperature parameter of the evaporator.

[0065] Specifically, by combining the actual temperature in the test chamber and the temperature parameter of the evaporator, the operation of the evaporator is considered instead of adjusting only according to the temperature of the test chamber. By combining the actual temperature in the test chamber and the temperature change caused by the operation of the evaporator, the coupled calculation of the gas bypass flow and the main flow of the refrigerant is realized, the opening of the gas bypass electromagnetic valve can be more accurately adjusted, and the temperature of the environmental test chamber can be more accurately adjusted. Moreover, by controlling the opening of the gas bypass electromagnetic valve, the gas flow of the main circuit can be adjusted to supplement the compressor, so that the oil return of the compressor is smoother, the risk of oil shortage of the compressor is avoided, and the operation reliability of the environmental test chamber is improved. Moreover, by precisely controlling the opening of the gas bypass electromagnetic valve, the opening of the gas bypass electromagnetic valve can be avoided to be too large, and the energy consumption of the system can be reduced.

[0066] S140, according to the actual temperature in the chamber, the initial temperature, the bypass temperature, the temperature parameter of the evaporator and the temperature parameter of the compressor, the opening of the liquid bypass electromagnetic valve is controlled according to the proportional integral differential control strategy.

[0067] The bypass temperature is the temperature between the bypass (the junction of the liquid bypass and the gas bypass) and the compressor inlet.

[0068] Specifically, the bypass temperature is related to the operation of the compressor and the evaporator, so the operation of the compressor and the evaporator is considered, the coupled calculation of the gas bypass flow, the main flow of the refrigerant and the liquid bypass flow is realized, the opening of the liquid bypass electromagnetic valve can be more accurately adjusted, and the temperature of the environmental test chamber can be more accurately adjusted. Moreover, by controlling the opening of the liquid bypass electromagnetic valve, the refrigerant flow of the main circuit can be adjusted, so that the temperature of the main circuit is adjusted, the suction temperature of the compressor is ensured, the temperature rise caused by the gas bypass supplement can be avoided, and the temperature of the environmental test chamber can be more accurately adjusted. Moreover, by precisely controlling the opening of the liquid bypass electromagnetic valve, the opening of the liquid bypass electromagnetic valve can be avoided to be too large, and the energy consumption of the system can be reduced.

[0069] S150, it is judged whether the actual temperature in the chamber reaches the final temperature, if yes, the process is ended, if not, the process returns to step S110.

[0070] Specifically, by continuously controlling the opening of the main circuit electromagnetic valve, the opening of the gas bypass electromagnetic valve and the opening of the liquid bypass electromagnetic valve until the actual temperature in the chamber reaches the final temperature, the temperature adjustment is completed, and the cooling of the test chamber is completed, so that the cooling test of the device in the test chamber is facilitated.

[0071] The technical scheme of the embodiment controls the opening degree of the main path electromagnetic valve according to the proportional integral differential strategy according to the actual temperature in the box and the target temperature, controls the opening degree of the gas bypass electromagnetic valve according to the proportional integral differential control strategy according to the actual temperature in the box, the initial temperature and the temperature parameter of the evaporator, and controls the opening degree of the liquid bypass electromagnetic valve according to the proportional integral differential control strategy according to the actual temperature in the box, the initial temperature, the bypass temperature, the temperature parameter of the evaporator and the temperature parameter of the compressor, realizes the coupling calculation of the refrigerant main path flow, the gas bypass flow and the liquid bypass flow, can more accurately adjust the opening degrees of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve, and thus more accurately adjusts the temperature of the environmental test chamber. Moreover, the compressor oil return can be smoother, the risk of oil shortage of the compressor can be avoided, and the operation reliability of the environmental test chamber is improved. Through the accurate control of the opening degrees of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve, the opening degrees of the gas bypass electromagnetic valve and the liquid bypass electromagnetic valve can be avoided to be too large, and the system energy consumption is reduced.

[0072] On the basis of the above technical scheme, the steps S120 and S130 in the above scheme are specifically described below, but not as a limitation of the present application.

[0073] Figure 2 is a flow chart of another environmental test chamber temperature control method provided by the embodiment of the present application, and optionally, reference is made to Figure 2 The environmental test chamber temperature control method comprises the following steps.

[0074] S210, determining the target temperature at the current time according to the final temperature of the environmental test chamber and the adjustment step value; wherein the target temperature is less than the initial temperature of the environmental test chamber and greater than or equal to the final temperature. The initial temperature is the temperature of the environmental test chamber when the adjustment starts.

[0075] S220, controlling the opening degree of the main path electromagnetic valve according to the proportional integral differential strategy according to the actual temperature in the box and the target temperature.

[0076] S230, controlling the opening degree of the gas bypass electromagnetic valve according to the proportional integral differential control strategy according to the first deviation value of the actual temperature in the box and the initial temperature, the second deviation value of the actual temperature in the box and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature.

[0077] Specifically, by controlling the opening degree of the gas bypass electromagnetic valve according to the first deviation value of the actual temperature in the box and the initial temperature, the second deviation value of the actual temperature in the box and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature, the work of the evaporator is considered when adjusting the opening degree of the gas bypass electromagnetic valve, instead of only adjusting according to the temperature of the test box. By combining the actual temperature in the test box and the temperature change caused by the work of the evaporator, the coupling calculation of the refrigerant main road flow and the gas bypass flow is realized, the opening degree of the gas bypass electromagnetic valve can be adjusted more accurately, and the temperature of the environmental test chamber can be adjusted more accurately. Moreover, by controlling the opening degree of the gas bypass electromagnetic valve, the gas flow of the main road can be adjusted to supplement the gas for the compressor, so that the oil return of the compressor is smoother, the risk of oil shortage of the compressor is avoided, and the operation reliability of the environmental test chamber is improved. Moreover, by precisely controlling the opening degree of the gas bypass electromagnetic valve, the opening degree of the gas bypass electromagnetic valve can be avoided to be too large, and the system energy consumption is increased.

[0078] S240, according to the first deviation value, the fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, the sixth deviation value of the bypass temperature and the evaporator outlet temperature, and the seventh deviation value of the bypass temperature and the compressor suction temperature, the opening degree of the liquid bypass electromagnetic valve is controlled according to the proportional integral derivative control strategy.

[0079] Specifically, by controlling the opening degree of the liquid bypass electromagnetic valve according to the first deviation value, the fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, the sixth deviation value of the bypass temperature and the evaporator outlet temperature, and the seventh deviation value of the bypass temperature and the compressor suction temperature, the bypass temperature is related to the work of the compressor and the evaporator, so the work of the compressor and the evaporator is considered, the coupling calculation of the refrigerant main road flow, the gas bypass flow and the liquid bypass flow is realized, the opening degree of the liquid bypass electromagnetic valve can be adjusted more accurately, and the temperature of the environmental test chamber can be adjusted more accurately. Moreover, by controlling the opening degree of the liquid bypass electromagnetic valve, the refrigerant flow of the main road can be adjusted, so that the main road temperature is adjusted, the suction temperature of the compressor is ensured, the temperature rise caused by the gas bypass gas supplement can be avoided, and the temperature of the environmental test chamber can be adjusted more accurately. Moreover, by precisely controlling the opening degree of the liquid bypass electromagnetic valve, the opening degree of the liquid bypass electromagnetic valve can be avoided to be too large, and the system energy consumption is increased.

[0080] S250, judging whether the actual temperature in the box reaches the final temperature, if yes, ending; if no, returning to execute step S210.

[0081] On the basis of the above technical solutions, Figure 3 is a flowchart of another environmental test chamber temperature control method provided by the embodiment of the present application, which can be optionally referred to Figure 3The temperature control method of the environmental test chamber comprises the following steps:

[0082] S310, determining a target temperature at the current time according to the final temperature of the environmental test chamber and the adjustment step value; wherein the target temperature is less than the initial temperature of the environmental test chamber and greater than or equal to the final temperature; wherein the initial temperature is the temperature of the environmental test chamber at the beginning of adjustment.

[0083] S320, controlling the opening degree of the main electromagnetic valve according to the proportional-integral-derivative strategy according to the actual temperature in the chamber and the target temperature.

[0084] S330, controlling the opening degree of the gas bypass electromagnetic valve according to the proportional-integral-derivative control strategy according to the first deviation value of the actual temperature in the chamber and the initial temperature, the second deviation value of the actual temperature in the chamber and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the chamber and the evaporator inlet temperature.

[0085] S340, controlling the opening degree of the liquid bypass electromagnetic valve according to the proportional-integral-derivative control strategy according to the first deviation value, the fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, the sixth deviation value of the bypass temperature and the evaporator outlet temperature, and the seventh deviation value of the bypass temperature and the compressor suction temperature.

[0086] S350, when the opening degree of the liquid bypass electromagnetic valve is greater than a preset threshold value, correcting the initial opening degree according to the opening degree of the liquid bypass electromagnetic valve.

[0087] Specifically, if the opening degree of the liquid bypass electromagnetic valve is less than or equal to a preset threshold value, for example, a small value, for example, 0.1%, it indicates that the liquid bypass electromagnetic valve is not opened, and the gas bypass electromagnetic valve can operate according to the initial opening degree. If the opening degree of the liquid bypass electromagnetic valve is greater than the preset threshold value, it indicates that the liquid bypass electromagnetic valve is opened, which will affect the system operating pressure, so it is necessary to adjust the opening degree of the gas bypass electromagnetic valve, correct the initial opening degree according to the opening degree of the liquid bypass electromagnetic valve, and avoid affecting the compressor oil return.

[0088] S360, judging whether the actual temperature in the chamber reaches the final temperature, if yes, ending; if no, returning to execute step S310.

[0089] On the basis of the above technical solution, optionally, correcting the initial opening degree according to the opening degree of the liquid bypass electromagnetic valve comprises the following steps:

[0090] Step a1, determining a target correction coefficient according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve, and the opening degree of the liquid bypass electromagnetic valve.

[0091] Specifically, when the liquid bypass electromagnetic valve is opened, the compressor suction temperature, the bypass temperature, the evaporator outlet temperature and the temperature of the environmental test chamber are affected, so that the target correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve, the coupling calculation of the gas bypass electromagnetic valve can be realized, so that the opening degree of the gas bypass electromagnetic valve can be corrected accurately, and the accurate control of the temperature of the environmental test chamber and the reliability of system operation are improved.

[0092] Step a2, updating the opening degree of the gas bypass electromagnetic valve according to the product of the opening degree of the gas bypass electromagnetic valve and the target correction coefficient.

[0093] Specifically, the initial opening degree of the gas bypass electromagnetic valve (determined according to the first deviation value, the second deviation value, the third deviation value and the fourth deviation value) is multiplied by the target correction coefficient to correct the initial opening degree of the gas bypass electromagnetic valve, so that the opening degree of the gas bypass electromagnetic valve can be matched with the opening degree of the liquid bypass electromagnetic valve.

[0094] Optionally, in step a1, the target correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve, and the target correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve.

[0095] Step a11, determining a first correction coefficient according to the fifth deviation value, the first deviation value, the third deviation value and the sixth deviation value.

[0096] For example, the compressor suction temperature is T a , the evaporator outlet temperature is T eo , the fifth deviation value is T a -T eo , the actual temperature in the chamber is T, the initial temperature is T0, the first deviation value is T0-T, the evaporator inlet temperature is T ei , the third deviation value is T eo -T ei , the bypass temperature is T gq , the sixth deviation value is T gq -T eo , and the first correction coefficient is wherein the actual temperature T in the chamber is greater than or equal to the final temperature and less than the initial temperature.

[0097] Step a12, determining a second correction coefficient according to the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve.

[0098] Specifically, the initial opening degree of the gas bypass electromagnetic valve (determined according to the first deviation value, the second deviation value, the third deviation value and the fourth deviation value) is U, the opening degree of the liquid bypass electromagnetic valve is Q, and the second correction coefficient is Wherein, λ is a parameter greater than 0, for example, λ is much smaller than the opening degree U of the gas bypass electromagnetic valve and the opening degree Q of the liquid bypass electromagnetic valve, and the specific value of λ can be set during actual debugging, and the embodiment is not limited. The second correction coefficient is related to the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve, so the opening degree of the gas bypass electromagnetic valve can be adjusted according to the opening degree of the liquid bypass electromagnetic valve.

[0099] Step a13, taking the maximum value of the first correction coefficient and the second correction coefficient as the target correction coefficient.

[0100] Specifically, when the first correction coefficient is larger, it indicates that the compressor suction temperature, the working of the evaporator and the temperature of the test box have greater influence on the gas bypass electromagnetic valve, and then the opening degree of the gas bypass electromagnetic valve is corrected according to the first correction coefficient. When the second correction coefficient is larger, it indicates that the opening degree of the liquid bypass electromagnetic valve has greater influence on the gas bypass electromagnetic valve, and then the opening degree of the gas bypass electromagnetic valve is corrected according to the second correction coefficient. In this way, the opening degree of the gas bypass electromagnetic valve can be accurately corrected, and the system operation reliability is improved.

[0101] Optionally, according to the first deviation value of the actual temperature in the box and the initial temperature, the second deviation value of the actual temperature in the box and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature, the opening degree of the gas bypass electromagnetic valve is determined according to a proportional-integral-derivative control strategy, comprising:

[0102] Step b1, taking the product of the first adjustment value of the first deviation value and the first ratio, the second ratio of the third deviation value and the first deviation value, and the third ratio of the fourth deviation value and the first deviation value as the first adjustment value.

[0103] Specifically, the second deviation value of the actual temperature in the box and the evaporator outlet temperature is T-T eo , the first deviation value is T0-T, the third deviation value is T eo -T ei , and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature is T-T ei , then the first adjustment value is

[0104] Step b2, taking the sum of the product of the first proportional coefficient and the first adjustment value, the product of the integral value of the product of the first integral coefficient and the first adjustment value, and the product of the differential value of the product of the first differential coefficient and the first adjustment value as the first target control quantity, so as to control the opening degree of the gas bypass electromagnetic valve according to the first target control quantity.

[0105] Specifically, the first proportional coefficient is K1, the first integral coefficient is I1, and the first differential coefficient is D1, then the first target control quantity corresponding to τ time is Where τ is greater than or equal to 0 and less than or equal to the total temperature adjustment time. The first target control quantity is, for example, the opening quantity, or the voltage value corresponding to the target opening degree (the opening degree corresponding to the target temperature) of the gas bypass solenoid valve. This allows the controller to control the opening degree of the gas bypass solenoid valve according to the first target control quantity, ensuring the flow rate of the compressor suction pipe, thereby ensuring the return of oil to the compressor. In this way, by combining the temperature of the test chamber and the operation of the evaporator, the opening degree of the gas bypass solenoid valve can be controlled, achieving precise control of the gas bypass solenoid valve.

[0106] Based on the above technical solutions, Figure 4 This is a flowchart of another environmental test chamber temperature control method provided in an embodiment of the present invention. Optionally, refer to... Figure 4 The temperature control methods for environmental test chambers include:

[0107] S410. Determine the target temperature at the current moment based on the final temperature of the environmental test chamber and the adjustment step value; wherein the target temperature is less than the initial temperature of the environmental test chamber and greater than or equal to the final temperature. The initial temperature is the temperature of the environmental test chamber at the start of adjustment.

[0108] S420: Based on the actual temperature inside the chamber and the target temperature, the opening degree of the main solenoid valve is controlled according to the proportional-integral-derivative strategy.

[0109] S430: Based on the first deviation value between the actual temperature inside the chamber and the initial temperature, the second deviation value between the actual temperature inside the chamber and the evaporator outlet temperature, the third deviation value between the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value between the actual temperature inside the chamber and the evaporator inlet temperature, the opening degree of the gas bypass solenoid valve is controlled according to the proportional-integral-derivative control strategy.

[0110] S440. The ratio of the fifth deviation value to the first deviation value is used as the second adjustment value.

[0111] Specifically, the compressor suction temperature T a With evaporator outlet temperature T eo The fifth deviation value is T a -T eo If the first deviation value is T0-T, then the second adjustment value is... This makes it easy to adjust the opening of the liquid bypass solenoid valve according to the operation of the compressor and evaporator.

[0112] S450, Use the ratio of the sixth deviation value to the seventh deviation value as the third adjustment value.

[0113] Specifically, bypass temperature T gq With evaporator outlet temperature T eo The sixth deviation value is T gq -T eo Bypass temperature Tgq a seventh deviation value of the compressor suction temperature T a gq -T a a third adjustment value is T In this way, the opening of the liquid bypass electromagnetic valve is adjusted according to the working of the evaporator, the working of the compressor and the bypass temperature.

[0114] S460, according to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to the proportional-integral-derivative control strategy.

[0115] Specifically, the second adjustment value or the third adjustment value is substituted into the proportional-integral-derivative control strategy, so that the opening of the liquid bypass electromagnetic valve is adjusted according to the working of the evaporator and the working of the compressor, which facilitates accurate control of the opening of the liquid bypass electromagnetic valve.

[0116] S470, it is judged whether the actual temperature in the tank reaches the final temperature, if yes, the process is ended, if not, the process returns to step S410.

[0117] Optionally, S460, according to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to the proportional-integral-derivative control strategy, including:

[0118] Step c1, the sum of the product of the second proportional coefficient and the second adjustment value, the product of the second integral coefficient and the integral value of the second adjustment value, and the product of the second differential coefficient and the differential value of the second adjustment value is taken as the first control quantity.

[0119] Specifically, the second proportional coefficient is K2, the second integral coefficient is I2, and the second differential coefficient is D2, and the first control quantity corresponding to τ is The first control quantity Q1 can be the opening value of the liquid bypass electromagnetic valve, or the voltage value corresponding to the opening value, so that the controller can control the opening of the liquid bypass electromagnetic valve according to the first control quantity.

[0120] Step c2, the sum of the product of the third proportional coefficient and the third adjustment value, the product of the third integral coefficient and the integral value of the third adjustment value, and the product of the third differential coefficient and the differential value of the third adjustment value is taken as the second control quantity.

[0121] Specifically, the third proportional coefficient is K3, the third integral coefficient is I3, and the third differential coefficient is D2, and the second control quantity corresponding to τ is The second control quantity Q2 can be the opening value of the liquid bypass electromagnetic valve, or the voltage value corresponding to the opening value, so that the controller can control the opening of the liquid bypass electromagnetic valve according to the second control quantity.

[0122] ​Step c3, taking the maximum value between the first control amount and the second control amount as the second target control amount to control the opening degree of the liquid bypass electromagnetic valve.

[0123] Specifically, when the first control amount is larger, it indicates that the second adjustment value is larger, and the compressor suction temperature, the evaporator outlet temperature and the actual temperature in the tank have greater influence on the flow of the liquid bypass electromagnetic valve. Therefore, the first control amount is taken as the second target control amount, i.e. the opening degree of the liquid bypass electromagnetic valve is adjusted according to the first control amount, which can better balance the compressor temperature and the temperature in the tank, facilitate accurate control of the temperature of the test chamber, and improve the reliability of system operation.

[0124] On the basis of the above technical solutions, in step S120 (S220 and S320), the opening degree of the main electromagnetic valve is controlled according to the proportional-integral-derivative strategy according to the actual temperature in the tank and the target temperature, comprising:

[0125] Step d1, calculating the temperature adjustment time according to the difference between the initial temperature and the final temperature and the temperature change rate.

[0126] Specifically, when the temperature of the environmental test chamber is controlled to rise, the difference between the initial temperature and the final temperature is the value of the final temperature minus the initial temperature; when the temperature of the environmental test chamber is controlled to fall, the difference between the initial temperature and the final temperature is the value of the initial temperature minus the final temperature. The temperature adjustment time can be obtained by taking the difference between the initial temperature and the final temperature as the temperature change rate, which can be preset.

[0127] Step d2, determining the fourth adjustment value according to the product of the actual temperature in the tank, the temperature change rate and the time difference, and the final temperature; wherein the time difference is the difference between the temperature adjustment time and the current time, and the target temperature is the target temperature corresponding to the current time.

[0128] Specifically, the temperature change rate is V, the temperature adjustment time is t, the time difference between the temperature adjustment time and the current time τ is t-τ, and the final temperature is T SV . The actual temperature in the tank is T, and the fourth adjustment value is e(τ) = T-(V·(t-τ)+T SV ).

[0129] Step d3, taking the sum of the product of the fourth proportional coefficient and the fourth adjustment value, the product of the fourth integral coefficient and the integral value of the fourth adjustment value, and the product of the fourth differential coefficient and the differential value of the fourth adjustment value as the third target control amount to control the opening degree of the main electromagnetic valve according to the third target control amount.

[0130] Specifically, the fourth proportional coefficient is K4, the fourth integral coefficient is I4, and the fourth differential coefficient is D4. The third target control amount corresponding to time τ is The third target control quantity is, for example, an opening degree quantity, and can also be a voltage value corresponding to a target opening degree (an opening degree corresponding to a target temperature) of the main circuit electromagnetic valve, so that the controller can control the opening degree of the main circuit electromagnetic valve according to the third target control quantity, so that the opening degree of the main circuit electromagnetic valve is the opening degree corresponding to the target temperature, and then the temperature of the test chamber is adjusted, so that the temperature of the test chamber reaches the target temperature corresponding to the τ moment.

[0131] The application further provides an environmental test chamber temperature control system, Figure 5 is a structural schematic diagram of an environmental test chamber temperature control system provided by an embodiment of the application, referring to Figure 5 The system comprises a controller 10, a main circuit 20, a gas bypass 30 and a liquid bypass 40; the controller 10 is used for executing the environmental test chamber temperature control method provided by any of the above embodiments;

[0132] The main circuit 20 comprises a compressor 201, a condenser 202, a main circuit electromagnetic valve 203 and an evaporator 204 connected in series; the liquid bypass 40 is connected between the inlet of the compressor 201 and the outlet of the condenser 202, and comprises a liquid bypass electromagnetic valve 401; the gas bypass 30 is connected between the inlet of the compressor 201 and the inlet of the condenser 202, and comprises a gas bypass electromagnetic valve 301; the controller 10 is connected with the main circuit electromagnetic valve 203, the liquid bypass electromagnetic valve 401 and the gas bypass electromagnetic valve 301 respectively.

[0133] Specifically, the controller 10 can control the opening degree of the main circuit electromagnetic valve 203 according to the actual temperature in the chamber and the target temperature according to a proportional-integral-derivative control strategy, control the opening degree of the gas bypass electromagnetic valve 301 according to the actual temperature in the chamber, the initial temperature and the temperature parameter of the evaporator 204 according to a proportional-integral-derivative control strategy, and control the opening degree of the liquid bypass electromagnetic valve 401 according to the actual temperature in the chamber, the initial temperature, the bypass temperature, the temperature parameter of the evaporator 204 and the temperature parameter of the compressor 201 according to a proportional-integral-derivative control strategy, so as to realize coupled calculation of the main circuit flow, the gas bypass flow and the liquid bypass flow, more accurately adjust the opening degrees of the gas bypass electromagnetic valve 301 and the liquid bypass electromagnetic valve 401, more accurately adjust the temperature of the environmental test chamber, and make the compressor return oil smoothly and reduce system energy consumption.

[0134] Figure 6 is a structural schematic diagram of another environmental test chamber temperature control system provided by an embodiment of the application, and optionally referring to Figure 6 The main circuit 20 further comprises a main circuit throttle valve 205, which is connected between the inlet of the evaporator 204 and the main circuit electromagnetic valve 203, and can throttle the refrigerant output by the main circuit electromagnetic valve 203.

[0135] The liquid bypass 40 further comprises a liquid bypass throttle valve 402, which is connected between the inlet of the compressor 201 and the liquid bypass solenoid valve 401, and can throttle the refrigerant output by the liquid bypass solenoid valve 401.

[0136] The gas bypass 30 further comprises a gas bypass throttle valve 302, which is connected between the inlet of the compressor 201 and the gas bypass solenoid valve 301, and can throttle the gas output by the gas bypass solenoid valve 301.

[0137] Optionally, referring to Figure 6 , the environmental test chamber temperature control system further comprises an in-chamber temperature sensor 501, an inlet temperature sensor 502, a bypass temperature sensor 503, an evaporator inlet temperature sensor 504 and an evaporator outlet temperature sensor 505;

[0138] The in-chamber temperature sensor 501 is located in the test chamber, and is connected to the controller 10, and is used to detect the actual temperature in the chamber and send it to the controller 10.

[0139] The inlet temperature sensor 502 is located at the inlet of the compressor 201, and can be connected to the controller 10, and is used to detect the suction temperature of the compressor 201 and send it to the controller 10.

[0140] The bypass temperature sensor 503 is located on the merging branch 50, which is the merging branch of the liquid bypass 40 and the gas bypass 30, and is connected between the inlet of the compressor 201 and the liquid bypass 40 (at the same time, it is connected between the inlet of the compressor 201 and the gas bypass 30), and can be connected to the controller 10, and is used to detect the bypass temperature and send it to the controller 10.

[0141] The evaporator inlet temperature sensor 504 is located at the inlet of the evaporator 204, and can be connected to the controller 10, and is used to detect the evaporator inlet temperature and send it to the controller 10.

[0142] The evaporator outlet temperature sensor 505 is located at the outlet of the evaporator 204, and can be connected to the controller 10, and is used to detect the evaporator outlet temperature and send it to the controller 10.

[0143] Specifically, by setting the box temperature sensor 501, the suction temperature sensor 502, the bypass temperature sensor 503, the evaporator inlet temperature sensor 504 and the evaporator outlet temperature sensor 505, the actual temperature in the box, the bypass temperature, the temperature parameter of the compressor (suction temperature), the temperature parameter of the evaporator (evaporator inlet temperature and evaporator outlet temperature) can be obtained in real time, so as to control the opening degree of the main road electromagnetic valve 203, the gas bypass electromagnetic valve 301 and the liquid bypass electromagnetic valve 401 according to the temperature of the test box, the bypass temperature, the temperature parameter of the compressor and the temperature parameter of the evaporator, so that the temperature of the test box reaches the target temperature set each time, and then the temperature of the environmental test chamber can realize linear cooling, which is convenient for testing the devices in the environmental test chamber.

[0144] It should be understood that the various forms of flow shown above can be reordered, added to, or deleted from without departing from the scope of the present application. For example, the steps described in the present application can be executed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, and the present application is not limited herein.

[0145] The above detailed description does not constitute a limitation on the protection scope of the present application. 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 modification, equivalent replacement and improvement within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A temperature control method for an environmental test chamber, characterized by, The temperature control system of the environmental test chamber is realized, and the system comprises a controller, a main circuit, a gas bypass and a liquid bypass; the main circuit comprises a compressor, a condenser, a main circuit electromagnetic valve and an evaporator connected in series; the liquid bypass is connected between the inlet of the compressor and the outlet of the condenser, and the liquid bypass comprises a liquid bypass electromagnetic valve; the gas bypass is connected between the inlet of the compressor and the inlet of the condenser, and the gas bypass comprises a gas bypass electromagnetic valve; the controller is connected with the main circuit electromagnetic valve, the liquid bypass electromagnetic valve and the gas bypass electromagnetic valve respectively; the method is executed by the controller; the method comprises: determining a target temperature at the current time according to the final temperature of the environmental test chamber and a regulation step value; wherein the target temperature is less than the initial temperature of the environmental test chamber and greater than or equal to the final temperature; controlling the opening degree of the main circuit electromagnetic valve according to the actual temperature in the chamber and the target temperature according to a proportional-integral-derivative control strategy; controlling the opening degree of the gas bypass electromagnetic valve according to the actual temperature in the chamber, the initial temperature and the temperature parameter of the evaporator according to a proportional-integral-derivative control strategy; controlling the opening degree of the liquid bypass electromagnetic valve according to the actual temperature in the chamber, the initial temperature, the bypass temperature, the temperature parameter of the evaporator and the temperature parameter of the compressor according to a proportional-integral-derivative control strategy, and returning to the step of determining the target temperature at the current time according to the final temperature of the environmental test chamber and the regulation step value until the actual temperature of the environmental test chamber reaches the final temperature; the bypass temperature is the temperature between the confluence of the liquid bypass and the gas bypass and the inlet of the compressor; controlling the opening degree of the gas bypass electromagnetic valve according to the actual temperature in the chamber, the initial temperature and the temperature parameter of the evaporator according to a proportional-integral-derivative control strategy, comprises: controlling the opening degree of the gas bypass electromagnetic valve according to the first deviation value of the actual temperature in the chamber and the initial temperature, the second deviation value of the actual temperature in the chamber and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the chamber and the evaporator inlet temperature according to a proportional-integral-derivative control strategy; controlling the opening degree of the liquid bypass electromagnetic valve according to the actual temperature in the chamber, the initial temperature, the bypass temperature, the temperature parameter of the evaporator and the temperature parameter of the compressor according to a proportional-integral-derivative control strategy, comprises: controlling the opening degree of the liquid bypass electromagnetic valve according to the first deviation value, the fifth deviation value of the compressor suction temperature and the evaporator outlet temperature, the sixth deviation value of the bypass temperature and the evaporator outlet temperature, and the seventh deviation value of the bypass temperature and the compressor suction temperature according to a proportional-integral-derivative control strategy; controlling the opening degree of the main circuit electromagnetic valve according to the actual temperature in the chamber and the target temperature according to a proportional-integral-derivative control strategy, comprises: calculating the temperature regulation time according to the difference value of the initial temperature and the final temperature and the temperature change rate; A fourth adjustment value is determined according to the actual temperature in the box, the product of the temperature change rate and the time difference, and the final temperature, wherein the time difference is the difference between the temperature adjustment time and the current time; A sum of a product of a fourth proportional coefficient and the fourth adjustment value, a product of a fourth integral coefficient and an integral value of the fourth adjustment value, and a product of a fourth differential coefficient and a differential value of the fourth adjustment value is taken as a third target control quantity, so as to control the opening degree of the main electromagnetic valve according to the third target control quantity.

2. The method of claim 1, wherein, After the opening degree of the liquid bypass electromagnetic valve is controlled according to the proportional integral differential control strategy based on the actual temperature in the box, the initial temperature, the bypass temperature, the temperature parameter of the evaporator, and the temperature parameter of the compressor, the method further comprises: When the opening degree of the liquid bypass electromagnetic valve is greater than a preset threshold, the opening degree of the gas bypass electromagnetic valve is corrected according to the opening degree of the liquid bypass electromagnetic valve.

3. The method of claim 2, wherein, The correction of the opening degree of the gas bypass electromagnetic valve according to the opening degree of the liquid bypass electromagnetic valve comprises: A target correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve, and the opening degree of the liquid bypass electromagnetic valve; The opening degree of the gas bypass electromagnetic valve is updated according to the product of the opening degree of the gas bypass electromagnetic valve and the target correction coefficient.

4. The method of claim 3, wherein, The determination of the target correction coefficient according to the fifth deviation value, the first deviation value, the third deviation value, the sixth deviation value, the opening degree of the gas bypass electromagnetic valve, and the opening degree of the liquid bypass electromagnetic valve comprises: A first correction coefficient is determined according to the fifth deviation value, the first deviation value, the third deviation value, and the sixth deviation value; A second correction coefficient is determined according to the opening degree of the gas bypass electromagnetic valve and the opening degree of the liquid bypass electromagnetic valve; The maximum value between the first correction coefficient and the second correction coefficient is taken as the target correction coefficient.

5. The method of claim 1, wherein, The control of the opening degree of the gas bypass electromagnetic valve according to the proportional integral differential control strategy based on the first deviation value of the actual temperature in the box and the initial temperature, the second deviation value of the actual temperature in the box and the evaporator outlet temperature, the third deviation value of the evaporator inlet temperature and the evaporator outlet temperature, and the fourth deviation value of the actual temperature in the box and the evaporator inlet temperature comprises: A first adjustment value is determined according to the product of the first ratio of the second deviation value and the first deviation value, the second ratio of the third deviation value and the first deviation value, and the third ratio of the fourth deviation value and the first deviation value; A sum of a product of a first proportional coefficient and the first adjustment value, a product of a first integral coefficient and an integral value of the first adjustment value, and a product of a first differential coefficient and a differential value of the first adjustment value is taken as a first target control quantity, so as to control the opening degree of the gas bypass electromagnetic valve according to the first target control quantity.

6. The method of claim 1, wherein, According to the first deviation value, a fifth deviation value of a compressor suction temperature and the evaporator outlet temperature, a sixth deviation value of a bypass temperature and the evaporator outlet temperature, a seventh deviation value of the bypass temperature and the compressor suction temperature, the opening of the liquid bypass electromagnetic valve is controlled according to a proportional-integral-derivative control strategy, comprising: The ratio of the fifth deviation value and the first deviation value is taken as a second adjustment value; The ratio of the sixth deviation value and the seventh deviation value is taken as a third adjustment value; According to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to a proportional-integral-derivative control strategy.

7. The method of claim 6, wherein, According to the second adjustment value or the third adjustment value, the opening of the liquid bypass electromagnetic valve is controlled according to a proportional-integral-derivative control strategy, comprising: The sum of the product of a second proportional coefficient and the second adjustment value, the product of a second integral coefficient and the integral value of the second adjustment value, and the product of a second derivative coefficient and the derivative value of the second adjustment value is taken as a first control amount; The sum of the product of a third proportional coefficient and the third adjustment value, the product of a third integral coefficient and the integral value of the third adjustment value, and the product of a third derivative coefficient and the derivative value of the third adjustment value is taken as a second control amount; The maximum value of the first control amount and the second control amount is taken as a second target control amount, so as to control the opening of the liquid bypass electromagnetic valve according to the second target control amount.

8. An environmental test chamber temperature control system characterized by, The system comprises a controller, a main circuit, a gas bypass and a liquid bypass; the controller is used to execute the environmental test chamber temperature control method of any one of claims 1-7; The main circuit comprises a compressor, a condenser, a main circuit electromagnetic valve and an evaporator connected in series; the liquid bypass is connected between the inlet of the compressor and the outlet of the condenser, and the liquid bypass comprises a liquid bypass electromagnetic valve; The gas bypass is connected between the inlet of the compressor and the inlet of the condenser, and the gas bypass comprises a gas bypass electromagnetic valve; The controller is connected with the main circuit electromagnetic valve, the liquid bypass electromagnetic valve and the gas bypass electromagnetic valve respectively.

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