Linear cooling control method and device for environmental test box and environmental test box

Abstract

The embodiment of the invention discloses an environmental test box linear cooling control method and device and an environmental test box. The method comprises the following steps: acquiring temperature description information corresponding to an environmental test box; the temperature description information comprises the initial temperature, the final temperature, the current temperature, the current cooling time and the total cooling time. Determining a linear cooling rate according to the temperature description information; according to the current temperature, the current cooling time and the linear cooling rate, the opening degree of a pulse electromagnetic valve is determined; determining the opening degree of the electronic expansion valve according to the opening degree of the pulse electromagnetic valve and the temperature description information; according to the opening degree of the pulse electromagnetic valve and the opening degree of the electronic expansion valve, the rotating speed of an evaporator fan is determined, and the rotating speed of the evaporator fan is used for controlling linear cooling of an environment test box. According to the technical scheme provided by the embodiment of the invention, the stability of a linear cooling temperature curve can be improved, the cooling rate adaptation range is enlarged, and the linear cooling effect of the environmental test box is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental test chamber data processing, and in particular to an environmental test chamber linear temperature reduction control method and device, and an environmental test chamber. Background Art

[0002] With the advancement of life and technology, the requirements for product reliability are getting higher and higher. In many fields, it is necessary to test the reliability, material stress changes, and changes in material properties of products or components when they are cooled from high temperature to low temperature within a certain period of time.

[0003] At present, most linear cooling uses fixed-frequency compressors. When the throttle valve uses an electronic expansion valve, although the device structure is simple and the curve stability is good, it is impossible to perform linear cooling at a higher rate due to the problem of the electronic expansion valve's own adjustment rate. When the linear cooling rate requirement is high, the throttle valve needs to use a multi-way combination, but at this time the device structure is complex, the curve stability is poor, and it cannot meet the low-rate linear cooling requirements.

[0004] The problem of poor linear cooling stability in existing environmental test chambers has become a technical problem that needs to be urgently solved in the industry. Summary of the invention

[0005] The present invention provides a method and device for controlling linear cooling of an environmental test chamber and an environmental test chamber to solve the problem of poor linear cooling stability of existing environmental test chambers. The present invention improves the stability of the linear cooling temperature curve and increases the applicable range of the cooling rate.

[0006] According to one aspect of the present invention, a method for linear temperature reduction control of an environmental test chamber is provided, comprising:

[0007] Obtain temperature description information corresponding to the environmental test chamber; wherein the temperature description information includes the starting temperature, the ending temperature, the current temperature, the current cooling time and the total cooling time;

[0008] Determining a linear cooling rate according to the temperature description information;

[0009] Determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate;

[0010] Determining the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information;

[0011] The speed of the evaporator fan is determined according to the opening of the pulse solenoid valve and the opening of the electronic expansion valve. The speed of the evaporator fan is used to control the linear cooling of the environmental test box.

[0012] Optionally, determining the linear cooling rate according to the temperature description information includes:

[0013] The linear cooling rate is determined according to the ratio of the difference between the starting temperature and the ending temperature to the total cooling time.

[0014] Optionally, determining the pulse solenoid valve opening according to the current temperature and the linear temperature drop rate includes:

[0015] Determine the pulse solenoid valve control deviation according to the linear temperature drop rate, the starting temperature, the ending temperature, the current temperature and the current temperature drop time;

[0016] The pulse solenoid valve control deviation is proportionally amplified, integrated and differentiated to determine the pulse solenoid valve opening.

[0017] Optionally, the calculation formula of the pulse solenoid valve control deviation is:

[0018]

[0019] The calculation formula of the pulse solenoid valve opening is:

[0020]

[0021] Among them, e 1 (τ) is the pulse solenoid valve control deviation, V is the linear cooling rate, T 0 is the starting temperature, T sv is the end temperature, t is the total cooling time, T is the current temperature, τ is the current cooling time, Z is the pulse solenoid valve opening, P 1 is the first proportionality coefficient, I 1 is the first integral coefficient, D 1 is the first differential coefficient, T 0 ≥T≥T sv ,t≥τ≥0.

[0022] Optionally, the temperature description information further includes: evaporator superheat and evaporator superheat control target value;

[0023] Determining the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information includes:

[0024] determining an electronic expansion valve control deviation according to a ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve control deviation, and the pulse solenoid valve opening;

[0025] Proportionally amplifying, integrating and differentiating the electronic expansion valve control deviation to determine a calculated opening of the electronic expansion valve;

[0026] The calculated opening of the electronic expansion valve and the minimum opening of the electronic expansion valve are maximized to generate a first maximum value, and the first maximum value and the maximum opening of the electronic expansion valve are minimized to determine the opening of the electronic expansion valve.

[0027] Optionally, the calculation formula of the electronic expansion valve control deviation is:

[0028]

[0029] The calculation formula for calculating the opening of the electronic expansion valve is:

[0030]

[0031] The calculation formula of the opening degree of the electronic expansion valve is:

[0032] E=MIN[E max , MAX[E min ,E 0 ]]

[0033] Among them, e 2 (τ) is the electronic expansion valve control deviation, k is the evaporator superheat, k obj is the evaporator superheat control target value, E 0 is the calculated opening of the electronic expansion valve, P 2 is the second proportionality coefficient, I 2 is the second integral coefficient, D 2 is the second differential coefficient, E is the opening of the electronic expansion valve, E max is the maximum opening of the electronic expansion valve, E min is the minimum opening of the electronic expansion valve, T 0 ≥T≥T sv ,t≥τ≥0.

[0034] Optionally, determining the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening includes:

[0035] determining an evaporator fan control deviation according to a ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening;

[0036] Proportionally amplifying, integrating and differentiating the evaporator fan control deviation to determine a calculated speed of the evaporator fan;

[0037] The calculated rotation speed of the evaporator fan and the minimum rotation speed of the evaporator fan are taken as the maximum value to generate a second maximum value, and the second maximum value and the maximum rotation speed of the evaporator fan are taken as the minimum value to determine the rotation speed of the evaporator fan.

[0038] Optionally, the calculation formula of the evaporator fan control deviation is:

[0039]

[0040] The calculation formula for the calculated speed of the evaporator fan is:

[0041]

[0042] The calculation formula of the evaporator fan speed is:

[0043] H=MIN[H max , MAX[H min ,H 0 ]]

[0044] Among them, e 3 (τ) is the evaporator fan control deviation, a is the electronic expansion valve opening coefficient, H 0 is the calculated speed of the evaporator fan, P 3 is the third proportionality coefficient, I 3 is the third integral coefficient, D 3 is the third differential coefficient, H is the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, T 0 ≥T≥T sv ,t≥τ≥0.

[0045] According to another aspect of the present invention, there is provided a linear temperature reduction control device for an environmental test chamber, comprising:

[0046] The temperature description information acquisition module is used to obtain the temperature description information corresponding to the environmental test box; wherein the temperature description information includes at least one of the following: starting temperature, ending temperature, current temperature, current cooling time and total cooling time;

[0047] An acquisition calculation control module is used to determine a linear cooling rate according to the temperature description information;

[0048] A pulse solenoid valve opening control module, used to determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate;

[0049] An electronic expansion valve opening control module, used to determine the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information;

[0050] The evaporator fan speed control module is used to determine the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening. The evaporator fan speed is used to control the linear cooling of the environmental test box.

[0051] According to another aspect of the present invention, there is provided an environmental test chamber, comprising:

[0052] A compressor, a condenser, a pulse solenoid valve, an electronic expansion valve, an evaporator, an evaporator fan, and a linear temperature reduction control device for an environmental test chamber provided in any of the above embodiments;

[0053] The compressor is connected to the condenser and the evaporator to form a series circuit; the pulse solenoid valve is connected between the condenser and the evaporator; the electronic expansion valve is connected between the pulse solenoid valve and the evaporator;

[0054] The evaporator and the evaporator fan are arranged correspondingly, the evaporator fan is connected to the environmental test box linear temperature reduction control device, and the environmental test box linear temperature reduction control device is electrically connected to the pulse solenoid valve and the electronic expansion valve.

[0055] Optionally, the environmental test chamber linear temperature reduction control device includes: an evaporator fan speed control module, an electronic expansion valve opening control module, a pulse solenoid valve opening control module, a collection calculation control module and a temperature description information acquisition module;

[0056] The temperature description information acquisition module includes: an in-box temperature sensor, an evaporator outlet temperature sensor and an evaporator outlet pressure sensor;

[0057] The in-box temperature sensor is arranged in the environmental test box, and the in-box temperature sensor is used to obtain the current temperature, the starting temperature and the ending temperature of the environmental test box;

[0058] The evaporator outlet temperature sensor is arranged at the outlet of the evaporator, and is used to obtain the temperature information of the evaporator outlet;

[0059] The evaporator outlet pressure sensor is arranged at the outlet of the evaporator, and is used to obtain the pressure information of the evaporator outlet; wherein the temperature information of the evaporator outlet and the pressure information of the evaporator outlet are used to calculate the superheat of the evaporator;

[0060] The acquisition calculation control module is connected to the temperature sensor in the box and is used to calculate the linear cooling rate according to the current temperature, the starting temperature and the ending temperature;

[0061] The pulse solenoid valve opening control module is connected to the pulse solenoid valve and is used to determine the pulse solenoid valve opening according to the current temperature and the linear temperature drop rate;

[0062] The electronic expansion valve opening control module is connected to the electronic expansion valve and is used to determine the opening of the electronic expansion valve according to the opening of the pulse solenoid valve and the superheat of the evaporator;

[0063] The evaporator fan is connected to the evaporator fan speed control module, and the evaporator fan speed control module is used to control the evaporator fan speed according to the opening of the pulse solenoid valve and the opening of the electronic expansion valve.

[0064] The technical solution of the embodiment of the present invention first obtains the temperature description information corresponding to the environmental test chamber, and determines the linear cooling rate of the environmental test chamber according to the temperature description information. Then, the pulse solenoid valve opening and the electronic expansion valve opening are calculated according to the linear cooling rate and the temperature description information. The pulse solenoid valve opening and the electronic expansion valve opening can accurately control the flow rate of the refrigerant in the environmental test chamber. Finally, the evaporator fan speed is determined according to the pulse solenoid valve opening and the electronic expansion valve opening, so that the evaporator fan has a corresponding speed. This embodiment controls the flow rate of the refrigerant by calculating the pulse solenoid valve opening and the electronic expansion valve opening, and controls the wind speed of the evaporator fan by calculating the evaporator fan speed, so that the refrigerant flow rate and the wind speed in the environmental test chamber cooperate with each other to jointly control the linear cooling of the environmental test chamber. By calculating the precise opening of the pulse solenoid valve and the opening of the electronic expansion valve, the flow of the refrigerant in the environmental test chamber can be reasonably controlled. By calculating the reasonable evaporator fan speed and adopting the corresponding evaporator fan speed, the refrigerant flow and the fan of the environmental test chamber can be coordinated with each other, avoiding the waste of resources. At the same time, it can also improve the stability of the linear cooling temperature curve of the environmental test chamber and increase the adaptability range of the cooling rate.

[0065] It should be understood that the contents described in this section are not intended to identify the key or important features of the embodiments of the present invention, nor are they intended to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0067] Figure 1 A flow chart of a linear temperature reduction control method for an environmental test chamber provided by an embodiment of the present invention;

[0068] Figure 2 A flow chart of another method for linear temperature reduction control of an environmental test chamber provided by an embodiment of the present invention;

[0069] Figure 3 A flow chart of another method for linear temperature reduction control of an environmental test chamber provided by an embodiment of the present invention;

[0070] Figure 4 A flow chart for determining the speed of an evaporator fan provided by an embodiment of the present invention;

[0071] Figure 5 A schematic diagram of the structure of a linear temperature reduction control device for an environmental test chamber provided by an embodiment of the present invention;

[0072] Figure 6 A schematic structural diagram of an environmental test chamber provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0073] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0074] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0075] Figure 1 The present invention provides a flow chart of a method for linear temperature reduction control of an environmental test chamber. This embodiment is applicable to the situation where the temperature is linearly controlled in an environmental test chamber. The method can be executed by a linear temperature reduction control device for an environmental test chamber, and the linear temperature reduction control device for an environmental test chamber can be implemented in the form of hardware and / or software.

[0076] like Figure 1 As shown, the linear temperature reduction control method of the environmental test chamber provided in this embodiment includes:

[0077] S110, obtaining temperature description information corresponding to the environmental test chamber, wherein the temperature description information includes a starting temperature, an ending temperature, a current temperature, a current cooling time, and a total cooling time.

[0078] Specifically, the starting temperature refers to the temperature at which the environmental test chamber starts the test. The ending temperature refers to the temperature at which the environmental test chamber test is completely finished. The current temperature refers to the temperature of the environmental test chamber at this time during the experiment. The current cooling time refers to the time taken for the environmental test chamber to cool from the starting temperature to the current temperature. The total cooling time refers to the total time taken for the environmental test chamber to cool from the starting temperature to the ending temperature.

[0079] Specifically, the current temperature in the environmental test chamber can be obtained by real-time detection by the temperature sensor in the chamber. The starting temperature of the environmental test chamber, the ending temperature of the environmental test chamber and the total cooling time of the environmental test chamber can be set by the acquisition calculation control module, which can be set according to actual conditions and is not specifically limited here.

[0080] S120: Determine a linear cooling rate according to the temperature description information.

[0081] Specifically, the linear cooling rate refers to a fixed temperature change rate that can be guaranteed within any time period. The linear cooling rate is a key technical parameter in the environmental test chamber. It ensures that the cooling rate remains constant within any time period, which is essential for achieving precise temperature control and simulating environmental conditions. The starting temperature, ending temperature and total cooling time in the temperature description information can be selected, and the linear cooling rate of the environmental test chamber can be determined by the temperature difference between the selected starting temperature and ending temperature and the total cooling time.

[0082] S130, determining the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate.

[0083] Specifically, the pulse solenoid valve mainly controls the flow of refrigerant in the environmental test chamber during the linear cooling process. The opening of the pulse solenoid valve is calculated based on the current temperature and current cooling time obtained in real time by the temperature sensor in the chamber and the linear cooling rate. By adjusting the opening of the pulse solenoid valve, the flow of refrigerant in the environmental test chamber can be controlled. Reasonable control of the flow of refrigerant can improve the temperature control accuracy of the environmental test chamber and make the linear cooling curve of the environmental test chamber closer to linear.

[0084] S140: Determine the opening of the electronic expansion valve according to the pulse solenoid valve opening and temperature description information.

[0085] Specifically, the electronic expansion valve can quickly and accurately adjust the flow of the refrigerant to adapt to changes in the refrigeration load. The flow of the refrigerant during the linear cooling of the environmental test chamber can be further controlled by adjusting the opening of the electronic expansion valve. The opening of the electronic expansion valve can be calculated by the opening of the pulse solenoid valve, the linear cooling rate of the environmental test chamber, the current temperature of the environmental test chamber, the pre-set starting temperature and end temperature, etc. Since the higher the control accuracy of the refrigerant flow, the closer the linear cooling curve of the environmental test chamber is to linearity, by adjusting the opening of the electronic expansion valve, the flow of the refrigerant is controlled again, and the temperature control accuracy of the environmental test chamber is further improved, which can effectively reduce the risk of the compressor of the environmental test chamber sucking liquid and improve the reliability of the system operation.

[0086] S150, determining the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening, and the evaporator fan speed is used to control the linear temperature reduction of the environmental test chamber.

[0087] Specifically, the evaporator fan can be used to control the linear cooling of the environmental test chamber, and the evaporator fan speed can represent the air output of the evaporator fan. The evaporator fan speed can be calculated by the pulse solenoid valve opening and the electronic expansion valve opening. In this embodiment, the linear cooling of the environmental test chamber is controlled by the mutual coordination of the pulse solenoid valve opening, the electronic expansion valve opening and the evaporator fan speed, thereby improving the stability of the linear cooling temperature curve, increasing the cooling rate adaptation range, and improving the linear cooling effect of the environmental test chamber.

[0088] The linear temperature reduction control method of the environmental test chamber provided in this embodiment first obtains the temperature description information corresponding to the environmental test chamber, and determines the linear temperature reduction rate of the environmental test chamber according to the temperature description information. Then, the pulse solenoid valve opening and the electronic expansion valve opening are calculated according to the linear temperature reduction rate and the temperature description information. The pulse solenoid valve opening and the electronic expansion valve opening can accurately control the flow rate of the refrigerant in the environmental test chamber. Finally, the evaporator fan speed is determined according to the pulse solenoid valve opening and the electronic expansion valve opening, so that the evaporator fan has a corresponding speed.

[0089] This embodiment controls the flow of refrigerant by calculating the pulse electromagnetic valve opening and the electronic expansion valve opening, and controls the wind speed of the evaporator fan by calculating the evaporator fan speed, so that the refrigerant flow and wind speed in the environmental test box cooperate with each other to jointly control the linear cooling of the environmental test box. By calculating the precise pulse electromagnetic valve opening and the electronic expansion valve opening, the flow of refrigerant in the environmental test box is reasonably controlled, and by calculating the reasonable evaporator fan speed, the corresponding evaporator fan speed is adopted, so that the refrigerant flow and fan of the environmental test box cooperate with each other, avoiding waste of resources, and at the same time, it can also improve the stability of the linear cooling temperature curve of the environmental test box and increase the adaptability range of the cooling rate.

[0090] Optional, Figure 2 A flow chart of another method for controlling the linear temperature drop of an environmental test chamber provided by an embodiment of the present invention. Figure 2 , the environmental test chamber linear temperature reduction control method provided by the embodiment of the present invention includes:

[0091] S210. Obtain temperature description information corresponding to the environmental test chamber, wherein the temperature description information includes a starting temperature, an ending temperature, a current temperature, a current cooling time, and a total cooling time.

[0092] S220, determining a linear cooling rate according to a ratio of a difference between the starting temperature and the ending temperature to the total cooling time.

[0093] Specifically, the linear cooling rate can be calculated by subtracting the end temperature from the pre-acquired starting temperature to obtain the required total cooling data, and then the linear cooling rate is calculated by dividing the total cooling data by the pre-set total cooling time. Among them, the starting temperature in the environmental test chamber, the end temperature in the environmental test chamber and the total cooling time can be set by the acquisition and calculation control module, which can be set according to actual conditions and is not specifically limited here. For example, the starting temperature is set to 80°C, the end temperature is set to 20°C, and the total cooling time is set to 30 minutes. It can be calculated that the total cooling data is 60°C, and the linear cooling rate is 2 (°C / min).

[0094] S230: Determine the opening of the pulse solenoid valve according to the current temperature, the current cooling time and the linear cooling rate.

[0095] S240: Determine the opening of the electronic expansion valve according to the pulse solenoid valve opening and temperature description information.

[0096] S250, determining the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening, and the evaporator fan speed is used to control the linear cooling of the environmental test chamber.

[0097] Optional, Figure 3 A flow chart of another method for controlling the linear temperature drop of an environmental test chamber provided by an embodiment of the present invention. Figure 3 , the environmental test chamber linear temperature reduction control method provided by the embodiment of the present invention includes:

[0098] S310, obtaining temperature description information corresponding to the environmental test chamber, wherein the temperature description information includes a starting temperature, an ending temperature, a current temperature, a current cooling time, and a total cooling time.

[0099] S320: Determine a linear cooling rate according to the temperature description information.

[0100] S331. Determine the pulse solenoid valve control deviation according to the linear cooling rate, the starting temperature, the ending temperature, the current temperature and the current cooling time.

[0101] Specifically, the control deviation of the pulse solenoid valve will affect the response speed and control accuracy of the pulse solenoid valve, and thus affect the performance of the entire environmental test chamber. The control deviation of the pulse solenoid valve can be determined by the pre-acquired starting temperature, end temperature, current temperature, current cooling time and calculated linear cooling rate. The control deviation of the pulse solenoid valve is an important indicator to measure the working performance of the pulse solenoid valve.

[0102] Among them, the pulse solenoid valve control deviation is calculated using the following formula:

[0103]

[0104] Among them, e 1 (τ) is the pulse solenoid valve control deviation, V is the linear cooling rate, T 0 is the starting temperature, T sv is the termination temperature, t is the total cooling time, T is the current temperature, τ is the current cooling time, T 0 ≥T≥T sv ,t≥τ≥0.

[0105] S332, proportionally amplify, integrate and differentiate the pulse solenoid valve control deviation to determine the pulse solenoid valve opening.

[0106] Specifically, the pulse solenoid valve opening can be obtained by proportionally amplifying, integrating and differentiating the pulse solenoid valve control deviation. According to the calculation result, the pulse solenoid valve can be quickly and stably controlled, thereby improving the stability of the environmental test chamber.

[0107] Among them, the pulse solenoid valve opening is calculated using the following formula:

[0108]

[0109] Among them, Z is the pulse solenoid valve opening, e 1 (τ) is the pulse solenoid valve control deviation, τ is the current cooling time, P 1 is the first proportionality coefficient, I 1 is the first integral coefficient, D 1 is the first differential coefficient.

[0110] S341. Determine the electronic expansion valve control deviation according to the ratio of the evaporator superheat to the evaporator superheat control target value and the pulse solenoid valve opening.

[0111] The temperature description information also includes: evaporator superheat and evaporator superheat control target value.

[0112] Specifically, the evaporator superheat can be calculated based on the temperature value detected by the evaporator outlet temperature sensor and the pressure value detected by the evaporator outlet pressure sensor. The evaporator outlet superheat target value can be set according to actual conditions and is not specifically limited here.

[0113] Specifically, the electronic expansion valve control deviation will affect the control accuracy and response speed of the electronic expansion valve. The electronic expansion valve control deviation is determined by calculating the ratio of the evaporator superheat to the preset evaporator superheat control target value, the pulse solenoid valve control deviation and the pulse solenoid valve opening, thereby improving the stability of the linear cooling of the environmental test chamber. At the same time, it can also reasonably control the flow of refrigerant in the environmental test chamber and reduce the waste of resources.

[0114] The electronic expansion valve control deviation is calculated using the following formula:

[0115]

[0116] Among them, e 2 (τ) is the electronic expansion valve control deviation, e 1 (τ) is the pulse solenoid valve control deviation, Z is the pulse solenoid valve opening, k is the evaporator superheat, k obj It is the target value for evaporator superheat control.

[0117] S342, proportionally amplify, integrate and differentiate the electronic expansion valve control deviation to determine the calculated opening of the electronic expansion valve.

[0118] Specifically, after determining the electronic expansion valve control deviation, PID control is performed on the electronic expansion valve control deviation to determine the calculated opening of the electronic expansion valve. The calculated opening of the electronic expansion valve can be calculated by proportionally amplifying, integrating and differentiating the electronic expansion valve control deviation.

[0119] The opening of the electronic expansion valve is calculated using the following formula:

[0120]

[0121] Among them, e 2 (τ) is the electronic expansion valve control deviation, E 0 is the calculated opening of the electronic expansion valve, τ is the current cooling time, P 2 is the second proportionality coefficient, I 2 is the second integral coefficient, D 2 is the second differential coefficient.

[0122] S343, taking the maximum value of the calculated opening of the electronic expansion valve and the minimum opening of the electronic expansion valve to generate a first maximum value, and taking the minimum value of the first maximum value and the maximum opening of the electronic expansion valve to determine the opening of the electronic expansion valve.

[0123] Specifically, the minimum opening of the electronic expansion valve and the maximum opening of the electronic expansion valve are set when the electronic expansion valve leaves the factory and are fixed. The first maximum value can be generated by taking the maximum value of the calculated opening of the electronic expansion valve and the minimum opening of the electronic expansion valve, and the opening of the electronic expansion valve can be determined by taking the minimum value of the first maximum value and the maximum opening of the electronic expansion valve. This ensures that the opening of the electronic expansion valve is between the maximum opening and the minimum opening, and avoids the calculated opening of the electronic expansion valve exceeding the allowable range of the opening.

[0124] The opening of the electronic expansion valve is calculated using the following formula:

[0125] E=MIN[E max , MAX[E min ,E 0 ]]

[0126] Among them, E is the opening degree of the electronic expansion valve, E 0 is the calculated opening of the electronic expansion valve, E max is the maximum opening of the electronic expansion valve, E min It is the minimum opening of the electronic expansion valve.

[0127] S350, determining the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening, and the evaporator fan speed is used to control the linear cooling of the environmental test chamber.

[0128] Optional, Figure 4 A flow chart for determining the speed of the evaporator fan provided by an embodiment of the present invention. Figure 4 , according to the pulse solenoid valve opening and the electronic expansion valve opening, determine the evaporator fan speed, including:

[0129] S410, determining the evaporator fan control deviation according to the ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening.

[0130] Specifically, the evaporator fan control deviation is determined by the ratio of the calculated evaporator superheat to a preset evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening.

[0131] The evaporator fan control deviation is calculated using the following formula:

[0132]

[0133] Among them, e 3 (τ) is the evaporator fan control deviation, Z is the pulse solenoid valve opening, E is the electronic expansion valve opening, a is the electronic expansion valve opening coefficient, k is the evaporator superheat, k obj It is the target value for evaporator superheat control.

[0134] S420, proportionally amplify, integrate and differentiate the evaporator fan control deviation to determine the calculated speed of the evaporator fan.

[0135] Specifically, after obtaining the evaporator fan control deviation, it is necessary to perform PID processing on the evaporator fan control deviation to determine the calculated speed of the evaporator fan. The calculated speed of the evaporator fan can be determined by proportionally amplifying, integrating and differentiating the evaporator fan control deviation.

[0136] The calculated speed of the evaporator fan is calculated using the following formula:

[0137]

[0138] Among them, H 0 is the calculated speed of the evaporator fan, e 3 (τ) is the evaporator fan control deviation, P 3 is the third proportionality coefficient, I 3 is the third integral coefficient, D 3 is the third differential coefficient, and 3 is the current cooling time.

[0139] S430, taking the maximum value of the calculated rotation speed of the evaporator fan and the minimum rotation speed of the evaporator fan to generate a second maximum value, and taking the minimum value of the second maximum value and the maximum rotation speed of the evaporator fan to determine the rotation speed of the evaporator fan.

[0140] Specifically, the maximum value is taken according to the calculated speed of the evaporator fan and the minimum speed of the evaporator fan, a second maximum value is generated, and the minimum value is taken between the second maximum value and the maximum speed of the evaporator fan to determine the speed of the evaporator fan. This ensures that the speed of the evaporator fan is within a reasonable range set by the manufacturer, avoiding exceeding the maximum value of the evaporator fan speed and being less than the minimum value of the evaporator fan speed.

[0141] Among them, the maximum value of the evaporator fan speed and the minimum value of the evaporator fan speed are set at the factory.

[0142] The evaporator fan speed is calculated using the following formula:

[0143] H=MIN[H max , MAX[H min ,H 0 ]]

[0144] Among them, H is the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, H 0 is the calculated speed of the evaporator fan.

[0145] This embodiment determines the evaporator fan control deviation by the ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening. The calculated speed of the evaporator fan is determined by performing PID control on the evaporator fan control deviation, thereby reducing the influence of the error in the process of calculating the evaporator fan speed. Finally, the final speed of the evaporator fan is determined according to the maximum speed of the evaporator fan, the minimum speed of the evaporator fan, and the calculated speed of the evaporator fan, thereby preventing the evaporator fan speed from exceeding the reasonable range set by the manufacturer.

[0146] This embodiment accurately calculates the evaporator fan speed so that the environmental test chamber adopts the corresponding wind speed, thereby improving the precise control of the temperature of the environmental test chamber, making the linear cooling curve of the environmental test chamber closer to linear, further improving the stability of the linear cooling temperature curve of the environmental test chamber, and increasing the adaptability range of the cooling rate.

[0147] An embodiment of the present invention also provides a linear temperature reduction control device for an environmental test chamber. Figure 5 The following is a schematic diagram of a linear temperature reduction control device for an environmental test chamber provided by an embodiment of the present invention. Figure 5 As shown, the environmental test chamber linear temperature reduction control device 100 includes:

[0148] The temperature description information acquisition module 10 is used to obtain the temperature description information corresponding to the environmental test box; wherein the temperature description information includes the starting temperature, the ending temperature, the current temperature, the current cooling time and the total cooling time.

[0149] The acquisition calculation control module 11 is used to determine the linear cooling rate according to the temperature description information.

[0150] The pulse solenoid valve opening control module 12 is used to determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate.

[0151] The electronic expansion valve opening control module 13 is used to determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate.

[0152] The evaporator fan speed control module 14 is used to determine the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening. The evaporator fan speed is used to control the linear temperature reduction of the environmental test chamber.

[0153] The embodiment of the present invention obtains the temperature description information corresponding to the environmental test box through the temperature description information acquisition module, calculates the linear cooling rate according to the temperature description information through the acquisition calculation module, determines the pulse solenoid valve opening by the pulse solenoid valve opening control module, determines the electronic expansion valve opening by the electronic expansion valve opening control module, and determines the evaporator fan speed control module. By reasonably controlling the evaporator fan speed and refrigerant flow, the stability of the linear cooling temperature curve is improved, the cooling rate adaptation range is increased, and the linear cooling control device of the environmental test box is simplified, reducing the energy consumption of the device.

[0154] The environmental test chamber linear temperature reduction control device provided in the embodiment of the present invention can execute the environmental test chamber linear temperature reduction control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the execution method.

[0155] The embodiment of the present invention further provides an environmental testing box 50 . Figure 6 The following is a schematic diagram of the structure of an environmental test chamber provided by an embodiment of the present invention. Figure 6 The environmental test chamber 50 includes: a compressor 2, a condenser 3, a pulse solenoid valve 4, an electronic expansion valve 5, an evaporator 7, an evaporator fan 6, and an environmental test chamber linear temperature reduction control device 100 provided in any of the above embodiments. The compressor 2 is connected to the condenser 3 and the evaporator 7 to form a series circuit; the pulse solenoid valve 4 is connected between the condenser 3 and the evaporator 7; the electronic expansion valve 5 is connected between the pulse solenoid valve 4 and the evaporator 7. The evaporator 7 and the evaporator fan 6 are arranged correspondingly, the evaporator fan 6 is connected to the environmental test chamber linear temperature reduction control device 100, and the environmental test chamber linear temperature reduction control device 100 is electrically connected to the pulse solenoid valve 4 and the electronic expansion valve 5.

[0156] Optionally, based on the above embodiments, the environmental test chamber linear cooling control device 100 includes: an evaporator fan speed control module 14, an electronic expansion valve opening control module 13, a pulse solenoid valve opening control module 12, an acquisition and calculation control module 11 and a temperature description information acquisition module 10.

[0157] The temperature description information acquisition module 10 includes: an in-box temperature sensor 1 , an evaporator outlet temperature sensor 8 and an evaporator outlet pressure sensor 9 .

[0158] The in-box temperature sensor 1 is arranged in the environmental test box, and the in-box temperature sensor 1 is used to obtain the current temperature, starting temperature and ending temperature of the environmental test box. The evaporator outlet temperature sensor 8 is arranged at the outlet of the evaporator 7, and is used to obtain the temperature information of the outlet of the evaporator 7. The evaporator outlet pressure sensor 9 is arranged at the outlet of the evaporator 7, and is used to obtain the pressure information of the outlet of the evaporator 7. Among them, the temperature information of the outlet of the evaporator 7 and the pressure information of the outlet of the evaporator 7 are used to calculate the superheat of the evaporator.

[0159] The acquisition calculation control module 11 is connected to the temperature sensor 1 in the box, and is used to calculate the linear cooling rate according to the current temperature, the starting temperature and the ending temperature. The pulse solenoid valve opening control module 12 is connected to the pulse solenoid valve 4, and is used to determine the pulse solenoid valve opening according to the current temperature and the linear cooling rate. The electronic expansion valve opening control module 13 is connected to the electronic expansion valve 5, and is used to determine the electronic expansion valve opening according to the pulse solenoid valve opening and the evaporator superheat.

[0160] The evaporator fan 6 is connected to the evaporator fan speed control module 14, and the evaporator fan speed control module 14 is used to control the speed of the evaporator fan 6 according to the opening of the pulse solenoid valve and the opening of the electronic expansion valve.

[0161] The environmental test chamber provided in this embodiment controls the flow rate of the refrigerant through a pulse solenoid valve and an electronic expansion valve, so that the flow rate of the refrigerant corresponds to the linear cooling curve. The speed of the evaporator fan is controlled by the evaporator fan control module, so that the environmental test chamber has a corresponding wind speed. The problem that the throttle valve needs to be set in a multi-way combination to participate in cooling when the linear cooling rate is required to be high in the prior art is solved. This embodiment improves the stability of the linear cooling temperature curve and increases the adaptability range of the cooling rate, while simplifying the system and reducing the energy consumption of the system operation.

[0162] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A linear temperature reduction control method for an environmental test chamber, characterized in that: include: Obtain temperature description information corresponding to the environmental test chamber; wherein the temperature description information includes the starting temperature, the ending temperature, the current temperature, the current cooling time and the total cooling time; Determining a linear cooling rate according to the temperature description information; Determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate; Determining the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information; The speed of the evaporator fan is determined according to the opening of the pulse solenoid valve and the opening of the electronic expansion valve. The speed of the evaporator fan is used to control the linear cooling of the environmental test box.

2. The linear temperature reduction control method of the environmental test chamber according to claim 1, characterized in that: The step of determining the linear cooling rate according to the temperature description information includes: The linear cooling rate is determined according to the ratio of the difference between the starting temperature and the ending temperature to the total cooling time.

3. The linear temperature reduction control method of the environmental test chamber according to claim 1 or 2, characterized in that: The step of determining the pulse solenoid valve opening according to the current temperature and the linear temperature drop rate comprises: Determine the pulse solenoid valve control deviation according to the linear temperature drop rate, the starting temperature, the ending temperature, the current temperature and the current temperature drop time; The pulse solenoid valve control deviation is proportionally amplified, integrated and differentiated to determine the pulse solenoid valve opening.

4. The linear temperature reduction control method of the environmental test chamber according to claim 3, characterized in that: The calculation formula of the pulse solenoid valve control deviation is: The calculation formula of the pulse solenoid valve opening is: Among them, e1(τ) is the pulse solenoid valve control deviation, V is the linear cooling rate, T0 is the starting temperature, T sv is the end temperature, t is the total cooling time, T is the current temperature, τ is the current cooling time, Z is the pulse solenoid valve opening, P1 is the first proportional coefficient, I1 is the first integral coefficient, D1 is the first differential coefficient, T0≥T≥T sv , t≥τ≥0.

5. The linear temperature reduction control method of the environmental test chamber according to claim 4, characterized in that: The temperature description information also includes: evaporator superheat and evaporator superheat control target value; Determining the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information includes: determining an electronic expansion valve control deviation according to a ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve control deviation, and the pulse solenoid valve opening; Proportionally amplifying, integrating and differentiating the electronic expansion valve control deviation to determine a calculated opening of the electronic expansion valve; The calculated opening of the electronic expansion valve and the minimum opening of the electronic expansion valve are maximized to generate a first maximum value, and the first maximum value and the maximum opening of the electronic expansion valve are minimized to determine the opening of the electronic expansion valve.

6. The linear temperature reduction control method of the environmental test chamber according to claim 5, characterized in that: The calculation formula of the electronic expansion valve control deviation is: The calculation formula for calculating the opening of the electronic expansion valve is: The calculation formula of the opening degree of the electronic expansion valve is: E=MIN[E max ,MAX[E min ,E0]] Among them, e2(τ) is the electronic expansion valve control deviation, k is the evaporator superheat, k obj is the evaporator superheat control target value, E0 is the calculated opening of the electronic expansion valve, P2 is the second proportional coefficient, I2 is the second integral coefficient, D2 is the second differential coefficient, E is the opening of the electronic expansion valve, E max is the maximum opening of the electronic expansion valve, E min is the minimum opening of the electronic expansion valve, T0≥T≥T sv , t≥τ≥0.

7. The linear temperature reduction control method of the environmental test chamber according to claim 5, characterized in that: The step of determining the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening includes: determining an evaporator fan control deviation according to a ratio of the evaporator superheat to the evaporator superheat control target value, the pulse solenoid valve opening, and the electronic expansion valve opening; Proportionally amplifying, integrating and differentiating the evaporator fan control deviation to determine a calculated speed of the evaporator fan; The calculated rotation speed of the evaporator fan and the minimum rotation speed of the evaporator fan are taken as the maximum to generate a second maximum value, and the second maximum value and the maximum rotation speed of the evaporator fan are taken as the minimum to determine the rotation speed of the evaporator fan.

8. The linear temperature reduction control method of the environmental test chamber according to claim 7, characterized in that: The calculation formula of the evaporator fan control deviation is: The calculation formula for the calculated speed of the evaporator fan is: The calculation formula of the evaporator fan speed is: h=MIN[H max ,MAX[H min ,H0]] Wherein, e3(τ) is the evaporator fan control deviation, a is the electronic expansion valve opening coefficient, H0 is the calculated speed of the evaporator fan, P3 is the third proportional coefficient, I3 is the third integral coefficient, D3 is the third differential coefficient, H is the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, T0≥T≥T sv , t≥τ≥0.

9. A linear temperature reduction control device for an environmental test chamber, characterized in that: include: The temperature description information acquisition module is used to obtain the temperature description information corresponding to the environmental test chamber; wherein the temperature description information includes at least one of the following: starting temperature, ending temperature, current temperature, current cooling time and total cooling time; An acquisition calculation control module is used to determine a linear cooling rate according to the temperature description information; A pulse solenoid valve opening control module, used to determine the pulse solenoid valve opening according to the current temperature, the current cooling time and the linear cooling rate; An electronic expansion valve opening control module, used to determine the opening of the electronic expansion valve according to the pulse solenoid valve opening and the temperature description information; The evaporator fan speed control module is used to determine the evaporator fan speed according to the pulse solenoid valve opening and the electronic expansion valve opening. The evaporator fan speed is used to control the linear cooling of the environmental test box.

10. An environmental test chamber, characterized in that: include: A compressor, a condenser, a pulse solenoid valve, an electronic expansion valve, an evaporator, an evaporator fan, and the linear temperature reduction control device of the environmental test chamber as claimed in claim 9; The compressor is connected to the condenser and the evaporator to form a series circuit; the pulse solenoid valve is connected between the condenser and the evaporator; the electronic expansion valve is connected between the pulse solenoid valve and the evaporator; The evaporator and the evaporator fan are arranged correspondingly, the evaporator fan is connected to the environmental test box linear temperature reduction control device, and the environmental test box linear temperature reduction control device is electrically connected to the pulse solenoid valve and the electronic expansion valve.

11. The environmental test chamber according to claim 10, characterized in that: The linear temperature reduction control device of the environmental test chamber comprises: an evaporator fan speed control module, an electronic expansion valve opening control module, a pulse solenoid valve opening control module, a collection calculation control module and a temperature description information acquisition module; The temperature description information acquisition module includes: an in-box temperature sensor, an evaporator outlet temperature sensor and an evaporator outlet pressure sensor; The in-box temperature sensor is arranged in the environmental test box, and the in-box temperature sensor is used to obtain the current temperature, the starting temperature and the ending temperature of the environmental test box; The evaporator outlet temperature sensor is arranged at the outlet of the evaporator, and is used to obtain the temperature information of the evaporator outlet; The evaporator outlet pressure sensor is arranged at the outlet of the evaporator, and is used to obtain the pressure information of the evaporator outlet; wherein the temperature information of the evaporator outlet and the pressure information of the evaporator outlet are used to calculate the superheat of the evaporator; The acquisition calculation control module is connected to the temperature sensor in the box and is used to calculate the linear cooling rate according to the current temperature, the starting temperature and the ending temperature; The pulse solenoid valve opening control module is connected to the pulse solenoid valve and is used to determine the pulse solenoid valve opening according to the current temperature and the linear temperature drop rate; The electronic expansion valve opening control module is connected to the electronic expansion valve and is used to determine the opening of the electronic expansion valve according to the opening of the pulse solenoid valve and the superheat of the evaporator; The evaporator fan is connected to the evaporator fan speed control module, and the evaporator fan speed control module is used to control the evaporator fan speed according to the opening of the pulse solenoid valve and the opening of the electronic expansion valve.

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