Linear cooling control method of environmental test box

Abstract

The invention discloses a linear cooling control method for an environmental test box. The method comprises the steps that the temperature in the environmental test box to be controlled, the suction pressure of a variable frequency compressor, the exhaust pressure of the variable frequency compressor, the air outlet temperature of an evaporator, the evaporation temperature, the air inlet temperature of a condenser and the linear cooling rate are obtained; according to the temperature in the box, the suction pressure of the variable-frequency compressor, the exhaust pressure of the variable-frequency compressor, the outlet air temperature of the evaporator, the evaporation temperature, the inlet air temperature of the condenser and the linear cooling rate, the rotating speed of the variable-frequency compressor, the opening degree of an electronic expansion valve, the rotating speed of an evaporator fan and the rotating speed of a condenser fan of the to-be-controlled environment test box are calculated; based on the calculated rotating speed of the inverter compressor, the calculated opening degree of the electronic expansion valve, the calculated rotating speed of the evaporator fan and the calculated rotating speed of the condenser fan, the inverter compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the environment test box to be controlled are controlled to act. The technical problems that in the prior art, a compressor is high in energy consumption, and system operation reliability is poor are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental test equipment, and particularly to a linear cooling control method for an environmental test chamber. Background Art

[0002] With the increasing progress 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, substance property changes, etc. of products or components during the process of cooling from high temperature to low temperature at a certain time.

[0003] During the linear cooling process, as the temperature drops, the demand for refrigeration capacity will increase. Moreover, as the temperature decreases, the evaporation temperature also needs to be reduced. When the condensation temperature is constant, the refrigeration capacity of the compressor will decrease as the evaporation temperature decreases. Therefore, there is a large difference in the compressor capacity exerted from the beginning to the end of the linear cooling process.

[0004] Currently, fixed-frequency compressors are mostly used for linear cooling. When selecting a compressor, it is based on the maximum refrigeration capacity demand during the linear cooling process, which will result in relatively high overall compressor energy consumption during the linear cooling process. In addition, the cooling capacity changes greatly during the linear cooling process, and the control of the evaporator fan and the condenser fan is also crucial. When the air volume of the evaporator fan and the condenser fan is too small, it will affect the system operation reliability and the exertion of the cooling capacity. When the air volume is too large, the energy saving performance is poor.

[0005] Therefore, optimizing the system control and operation during the linear cooling process is crucial for improving the system operation reliability and reducing the system operation energy consumption. Summary of the Invention

[0006] The present invention provides a linear cooling control method for an environmental test chamber to solve the technical problems of relatively high compressor energy consumption and relatively poor system operation reliability during the linear cooling process of the existing environmental test chamber.

[0007] According to one aspect of the present invention, there is provided a linear cooling control method for an environmental test chamber, including:

[0008] Obtaining the temperature inside the environmental test chamber to be controlled, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the outlet air temperature of the evaporator, the evaporation temperature, the inlet air temperature of the condenser, and the linear cooling rate;

[0009] Calculating the rotational speed of the variable-frequency compressor, the opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan of the environmental test chamber to be controlled respectively according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the outlet air temperature of the evaporator, the evaporation temperature, the inlet air temperature of the condenser, and the linear cooling rate;

[0010] Based on the calculated rotational speed of the variable-frequency compressor, the opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan, control the actions of the variable-frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the to-be-controlled environmental test chamber respectively.

[0011] Optionally, calculating the rotational speed of the variable-frequency compressor, the opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan of the to-be-controlled environmental test chamber according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the air outlet temperature of the evaporator, the evaporation temperature, the air inlet temperature of the condenser, and the linear cooling rate includes:

[0012] Calculate the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate;

[0013] Calculate the opening degree of the electronic expansion valve according to the temperature inside the chamber, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature, and the linear cooling rate;

[0014] Calculate the rotational speed of the evaporator fan according to the air outlet temperature of the evaporator, the evaporation temperature, and the suction pressure of the variable-frequency compressor;

[0015] Calculate the rotational speed of the condenser fan according to the air inlet temperature of the condenser and the discharge pressure of the variable-frequency compressor.

[0016] Optionally, calculating the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate includes:

[0017] Calculate the control deviation of the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate;

[0018] Calculate the rotational speed increment of the variable-frequency compressor according to the control deviation of the rotational speed of the variable-frequency compressor;

[0019] Calculate the rotational speed of the variable-frequency compressor according to the rotational speed increment of the variable-frequency compressor.

[0020] Optionally, calculating the opening degree of the electronic expansion valve according to the temperature inside the chamber, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature, and the linear cooling rate includes:

[0021] Calculate the control deviation of the electronic expansion valve according to the temperature inside the chamber, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature, and the linear cooling rate;

[0022] Calculate the opening degree increment of the electronic expansion valve according to the control deviation of the electronic expansion valve;

[0023] Calculate the opening degree of the electronic expansion valve based on the increment of the opening degree of the electronic expansion valve.

[0024] Optionally, calculating the rotational speed of the evaporator fan according to the outlet air temperature of the evaporator, the evaporation temperature, and the suction pressure of the variable-frequency compressor includes:

[0025] Calculate the control deviation of the rotational speed of the evaporator fan according to the outlet air temperature of the evaporator, the evaporation temperature, and the suction pressure of the variable-frequency compressor;

[0026] Calculate the increment of the rotational speed of the evaporator fan according to the control deviation of the evaporator fan;

[0027] Calculate the rotational speed of the evaporator fan according to the increment of the rotational speed of the evaporator fan.

[0028] Optionally, calculating the rotational speed of the condenser fan according to the inlet air temperature of the condenser and the discharge pressure of the variable-frequency compressor includes:

[0029] Calculate the control deviation of the rotational speed of the condenser fan according to the inlet air temperature of the condenser and the discharge pressure of the variable-frequency compressor;

[0030] Calculate the increment of the rotational speed of the condenser fan according to the control deviation of the condenser fan rotational speed;

[0031] Calculate the rotational speed of the condenser fan according to the increment of the rotational speed of the condenser fan.

[0032] Optionally, calculating the control deviation of the rotational speed of the variable-frequency compressor according to the temperature inside the box, the suction pressure of the variable-frequency compressor, and the linear cooling rate includes:

[0033] Calculate the control deviation of the rotational speed of the variable-frequency compressor using the following formula:

[0034] In the formula, T is the temperature inside the box, V is the linear cooling rate, LP is the suction pressure of the variable-frequency compressor, τ is any moment within the total cooling time t, e 1 (τ) is the control deviation of the rotational speed of the variable-frequency compressor;

[0035] Calculating the increment of the rotational speed of the variable-frequency compressor according to the control deviation of the rotational speed of the variable-frequency compressor includes:

[0036] Calculate the increment of the rotational speed of the variable-frequency compressor using the following formula:

[0037] ΔF(τ) = P 1 ·[e 1 (τ) - e 1 (τ - 1)] + I 1 ·e 1 (τ) + D 1 ·[e1 (τ) - 2e 1 (τ - 1) + e 1 (τ - 2)];

[0038] T 0 ≥T≥T SV , t≥τ≥0; Where ΔF(τ) is the speed increment of the variable - frequency compressor at time τ, P 1 is the speed control proportional coefficient of the variable - frequency compressor, I 1 is the speed control integral coefficient of the variable - frequency compressor, D 1 is the speed control differential coefficient of the variable - frequency compressor, τ, τ - 1, τ - 2 represent time τ, time τ - 1 and time τ - 2 respectively, T 0 is the preset start time, T SV is the preset end time;

[0039] The calculating the variable - frequency compressor speed according to the variable - frequency compressor speed increment includes:

[0040] Calculating the variable - frequency compressor speed using the following formula:

[0041] F(τ) = F(τ - 1)+ΔF(τ); Where F(τ) is the variable - frequency compressor speed at time τ, F(τ - 1) is the variable - frequency compressor speed at time τ - 1, and ΔF(τ) is the variable - frequency compressor speed increment at time τ.

[0042] Optionally, the calculating the electronic expansion valve control deviation according to the temperature inside the box, the air - outlet temperature of the evaporator, the evaporation temperature, the preset start temperature, and the linear cooling rate includes:

[0043] Calculating the electronic expansion valve control deviation using the following formula:

[0044] Where e 2 (τ) is the electronic expansion valve control deviation at time τ, T 9 is the air - outlet temperature of the evaporator, T EVA is the evaporation temperature, T 0 is the preset start temperature, T is the temperature inside the box, and V is the linear cooling rate;

[0045] The calculating the electronic expansion valve opening increment according to the electronic expansion valve control deviation includes:

[0046] Calculating the electronic expansion valve opening increment using the following formula:

[0047] ΔE(τ)=P 2 ·[e 2 (τ)-e 2 (τ - 1)]+I 2 ·e2 (τ) + D 2 ·[e 2 (τ) - 2e 2 (τ - 1) + e 2 (τ - 2)];

[0048] T 0 ≥ T ≥ T SV , t ≥ τ ≥ 0; Wherein, ΔE(τ) is the opening increment of the electronic expansion valve at time τ, P 2 is the opening control proportional coefficient of the electronic expansion valve, I 2 is the opening control integral coefficient of the electronic expansion valve, D 2 is the opening control differential coefficient of the electronic expansion valve, τ, τ - 1, τ - 2 respectively represent time τ, time τ - 1 and time τ - 2;

[0049] Calculating the opening of the electronic expansion valve according to the opening increment of the electronic expansion valve includes:

[0050] Calculating the opening of the electronic expansion valve using the following formula:

[0051] E(τ) = E(τ - 1) + ΔE(τ); Wherein, E(τ) is the opening of the electronic expansion valve at time τ, E(τ - 1) is the opening of the electronic expansion valve at time τ - 1, and ΔE(τ) is the opening increment of the electronic expansion valve at time τ.

[0052] Optionally, calculating the control deviation of the evaporator fan speed according to the outlet air temperature of the evaporator, the evaporation temperature and the suction pressure of the variable frequency compressor includes:

[0053] Calculating the control deviation of the evaporator fan using the following formula:

[0054] Wherein, e 3 (τ) is the control deviation of the evaporator fan speed at time (τ), T 9 is the outlet air temperature of the evaporator, T EVA is the evaporation temperature, and LP is the suction pressure of the variable frequency compressor;

[0055] Calculating the speed increment of the evaporator fan according to the control deviation of the evaporator fan includes:

[0056] Calculating the speed increment of the evaporator fan using the following formula:

[0057] ΔH(τ) = P 3 ·[e 3 (τ) - e 3 (τ - 1)] + I 3 ·e 3 (τ) + D 3 ·[e 3(τ) - 2e 3 (τ - 1) + e 3 (τ - 2);

[0058] T 0 ≥T≥T SV , t≥τ≥0; Wherein, ΔH(τ) is the increment of the evaporator fan speed at time τ, P 3 is the evaporator fan speed control proportionality coefficient, I 3 is the evaporator fan speed control integral coefficient, D 3 is the evaporator fan speed control differential coefficient, τ, τ - 1, τ - 2 respectively represent the time τ, the time τ - 1 and the time τ - 2;

[0059] Calculating the evaporator fan speed according to the evaporator fan speed increment includes:

[0060] Use the following formula to calculate the evaporator fan speed:

[0061] H(τ) = H(τ - 1) + ΔH(τ); Wherein, H(τ) is the evaporator fan speed at time τ, H(τ - 1) is the evaporator fan speed at time τ - 1, and ΔH(τ) is the increment of the evaporator fan speed at time τ.

[0062] Optionally, calculating the condenser fan speed control deviation according to the condenser inlet air temperature and the variable frequency compressor discharge pressure includes:

[0063] Use the following formula to calculate the condenser fan speed control deviation:

[0064] Wherein, e 4 (τ) is the condenser fan speed control deviation at time τ, T 5 is the condenser inlet air temperature, and HP is the variable frequency compressor discharge pressure;

[0065] Calculating the condenser fan speed increment according to the condenser fan speed control deviation includes:

[0066] Use the following formula to calculate the condenser fan speed increment:

[0067] ΔC(τ) = P 4 ·[e 4 (τ) - e 4 (τ - 1)] + I 4 ·e 4 (τ) + D 4 ·[e 4 (τ) - 2e 4 (τ - 1) + e 4 (τ - 2);

[0068] T 0 ≥T≥T SV ,t≥τ≥0; Wherein, ΔC(τ) is the increment of the condenser fan speed at time τ, P 4 is the proportional coefficient of the condenser fan speed control, I 4 is the integral coefficient of the condenser fan speed control, D 4 is the differential coefficient of the condenser fan speed control, τ, τ-1, and τ-2 respectively represent the time τ, the time τ-1, and the time τ-2;

[0069] The calculating the condenser fan speed according to the increment of the condenser fan speed includes:

[0070] Calculating the condenser fan speed by using the following formula:

[0071] C(τ) = C(τ-1) + ΔC(τ); Wherein, C(τ) is the condenser fan speed at time τ, C(τ-1) is the condenser fan speed at time τ-1, and ΔC(τ) is the increment of the condenser fan speed at time τ.

[0072] An embodiment of the present invention provides a linear cooling control method for an environmental test chamber, including: obtaining the temperature inside the chamber, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the air outlet temperature of the evaporator, the evaporation temperature, the air inlet temperature of the condenser, and the linear cooling rate of the environmental test chamber to be controlled; calculating the variable-frequency compressor speed, the opening of the electronic expansion valve, the evaporator fan speed, and the condenser fan speed of the environmental test chamber to be controlled respectively according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the air outlet temperature of the evaporator, the evaporation temperature, the air inlet temperature of the condenser, and the linear cooling rate; controlling the actions of the variable-frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the environmental test chamber to be controlled respectively based on the calculated variable-frequency compressor speed, the opening of the electronic expansion valve, the evaporator fan speed, and the condenser fan speed. The technical solution provided by the embodiment of the present invention solves the technical problems of high compressor energy consumption and poor system operation reliability during the linear cooling process of the existing environmental test chamber by accurately calculating the variable-frequency compressor speed, the opening of the electronic expansion valve, the evaporator fan speed, and the condenser fan speed, and using the calculation results to control the corresponding mechanisms, realizes the improvement of the stability of the linear cooling control of the environmental test chamber and the system operation reliability, and reduces the technical effects of compressor energy consumption and fan energy consumption.

[0073] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. Description of the Drawings

[0074] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for description in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0075] Figure 1 It is a flowchart of a linear cooling control method for an environmental test chamber provided by an embodiment of the present invention;

[0076] Figure 2 It is a flowchart of another linear cooling control method for an environmental test chamber provided by an embodiment of the present invention;

[0077] Figure 3 It is a schematic structural diagram of an environmental test chamber provided by an embodiment of the present invention. Detailed implementation manners

[0078] In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0079] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above drawings 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 under appropriate circumstances 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 "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those clearly listed steps or units, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0080] Figure 1 It is a flowchart of a linear cooling control method for an environmental test chamber provided by an embodiment of the present invention. Refer to Figure 1 and the method includes:

[0081] S110. Obtain the temperature inside the environmental test chamber to be controlled, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the air outlet temperature of the evaporator, the evaporation temperature, the air inlet temperature of the condenser, and the linear cooling rate.

[0082] Among them, an environmental test chamber is a device used to simulate various environmental conditions to test the performance and reliability of products or materials under different environments. The environmental test chamber can simulate various environmental factors, such as temperature, humidity, air pressure, light, vibration, etc. By placing the product or material in the test chamber and conducting tests under the set environmental conditions for a period of time, it is possible to understand the situations that the product may face in the actual use environment, so as to improve and optimize the product.

[0083] Specifically, a box temperature sensor, a condenser inlet air temperature sensor, an evaporator outlet air temperature sensor, a compressor suction pressure sensor, and a compressor discharge pressure sensor are provided inside the environmental test chamber to be controlled. The box temperature, the variable-frequency compressor suction pressure, the variable-frequency compressor discharge pressure, the evaporator outlet air temperature, the evaporation temperature, and the condenser inlet air temperature of the environmental test chamber to be controlled can be obtained respectively through the box temperature sensor, the condenser inlet air temperature sensor, the evaporator outlet air temperature sensor, the compressor suction pressure sensor, and the compressor discharge pressure sensor inside the environmental test chamber to be controlled. Among them, the evaporation temperature and the linear cooling rate can be obtained through calculation; the evaporation temperature can be calculated through the compressor suction pressure, and the linear cooling rate can be calculated through the preset starting temperature, the preset ending temperature, and the preset total cooling time.

[0084] S120. Calculate the variable-frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed, and the condenser fan speed of the environmental test chamber to be controlled respectively according to the box temperature, the variable-frequency compressor suction pressure, the variable-frequency compressor discharge pressure, the evaporator outlet air temperature, the evaporation temperature, the condenser inlet air temperature, and the linear cooling rate.

[0085] Specifically, after obtaining the box temperature, the variable-frequency compressor suction pressure, the variable-frequency compressor discharge pressure, the evaporator outlet air temperature, the evaporation temperature, the condenser inlet air temperature, and the linear cooling rate, use the variable-frequency compressor speed formula, the electronic expansion valve opening formula, the evaporator fan speed formula, and the condenser fan speed formula to calculate the opening or speed of the variable-frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the environmental test chamber to be controlled respectively.

[0086] S130. Control the actions of the variable-frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the environmental test chamber to be controlled respectively based on the calculated variable-frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed, and the condenser fan speed.

[0087] Specifically, the calculated rotational speed of the variable-frequency compressor, the opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan are used to control the variable-frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the environmental test chamber to be controlled. Since the linear cooling rate is involved in the process of calculating the rotational speed of the variable-frequency compressor, and the linear cooling rate can characterize the refrigerant flow rate, by using the calculated rotational speed of the variable-frequency compressor to control the variable-frequency compressor of the environmental test chamber to be controlled, the refrigeration capacity of the compressor is matched with the required refrigeration capacity, reducing the energy consumption of the compressor; by using the calculated opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan to control the electronic expansion valve, the evaporator fan, and the condenser fan of the environmental test chamber to be controlled, the purpose of further controlling the refrigeration capacity is achieved, and then the stable linear cooling control of the environmental test chamber to be controlled is realized, increasing the adaptability range of the cooling rate. At the same time, the rotational speeds of the evaporator fan and the condenser fan are controlled according to the change of the refrigeration capacity demand, effectively reducing the energy consumption of the fan on the basis of improving the operation reliability of the system.

[0088] The technical solution provided by the embodiment of the present invention, by accurately calculating the rotational speed of the variable-frequency compressor, the opening degree of the electronic expansion valve, the rotational speed of the evaporator fan, and the rotational speed of the condenser fan, and using the calculation results to control the corresponding mechanisms, solves the technical problems of high compressor energy consumption and poor system operation reliability in the linear cooling process of the existing environmental test chamber, realizes the improvement of the stability of the linear cooling control of the environmental test chamber and the operation reliability of the system, and reduces the technical effects of the compressor energy consumption and the fan energy consumption.

[0089] Figure 2 FIG. is a flowchart of another linear cooling control method for an environmental test chamber provided by an embodiment of the present invention. The embodiment of the present invention further refines the foregoing embodiment on the basis of the above embodiment. Refer to Figure 2 and the method includes:

[0090] S210. Obtain the temperature inside the environmental test chamber to be controlled, the suction pressure of the variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the outlet air temperature of the evaporator, the evaporation temperature, the inlet air temperature of the condenser, and the linear cooling rate.

[0091] S220. Calculate the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate.

[0092] Optionally, calculating the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate includes:

[0093] Calculate the control deviation of the rotational speed of the variable-frequency compressor according to the temperature inside the chamber, the suction pressure of the variable-frequency compressor, and the linear cooling rate.

[0094] Specifically, the following formula is used to calculate the speed control deviation of the variable-frequency compressor:

[0095] In the formula, T is the temperature inside the box, V is the linear cooling rate, LP is the suction pressure of the variable-frequency compressor, τ is any moment within the total cooling time t, and e 1 (τ) is the speed control deviation of the variable-frequency compressor.

[0096] Calculate the speed increment of the variable-frequency compressor based on the speed control deviation of the variable-frequency compressor.

[0097] Specifically, the following formula is used to calculate the speed increment of the variable-frequency compressor:

[0098] ΔF(τ) = P 1 ·[e 1 (τ) - e 1 (τ - 1)] + I 1 ·e 1 (τ) + D 1 ·[e 1 (τ) - 2e 1 (τ - 1) + e 1 (τ - 2)];

[0099] T 0 ≥T≥T SV , t≥τ≥0; In the formula, ΔF(τ) is the speed increment of the variable-frequency compressor at the moment τ, P 1 is the speed control proportionality coefficient of the variable-frequency compressor, I 1 is the speed control integral coefficient of the variable-frequency compressor, D 1 is the speed control differential coefficient of the variable-frequency compressor, τ, τ - 1, and τ - 2 respectively represent the moment τ, the moment τ - 1, and the moment τ - 2, T 0 is the preset start time, T SV is the preset end time.

[0100] Calculate the speed of the variable-frequency compressor based on the speed increment of the variable-frequency compressor.

[0101] Specifically, the following formula is used to calculate the speed of the variable-frequency compressor:

[0102] F(τ) = F(τ - 1) + ΔF(τ); In the formula, F(τ) is the speed of the variable-frequency compressor at the moment τ, F(τ - 1) is the speed of the variable-frequency compressor at the moment τ - 1, and ΔF(τ) is the speed increment of the variable-frequency compressor at the moment τ.

[0103] S230. Calculate the opening degree of the electronic expansion valve according to the temperature inside the box, the outlet air temperature of the evaporator, the evaporation temperature, the preset start temperature, and the linear cooling rate.

[0104] Optionally, calculating the opening degree of the electronic expansion valve based on the temperature inside the box, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature, and the linear cooling rate includes:

[0105] Calculating the control deviation of the electronic expansion valve based on the temperature inside the box, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature, and the linear cooling rate.

[0106] Specifically, the following formula is used to calculate the control deviation of the electronic expansion valve:

[0107] In the formula, e 2 (τ) is the control deviation of the electronic expansion valve at time τ, T 9 is the air outlet temperature of the evaporator, T EVA is the evaporation temperature, T 0 is the preset starting temperature, T is the temperature inside the box, and V is the linear cooling rate.

[0108] Calculating the opening degree increment of the electronic expansion valve based on the control deviation of the electronic expansion valve.

[0109] Specifically, the following formula is used to calculate the opening degree increment of the electronic expansion valve:

[0110] ΔE(τ) = P 2 ·[e 2 (τ) - e 2 (τ - 1)] + I 2 ·e 2 (τ) + D 2 ·[e 2 (τ) - 2e 2 (τ - 1) + e 2 (τ - 2)];

[0111] T 0 ≥T≥T SV , t≥τ≥0; In the formula, ΔE(τ) is the opening degree increment of the electronic expansion valve at time τ, P 2 is the proportional coefficient of the opening degree control of the electronic expansion valve, I 2 is the integral coefficient of the opening degree control of the electronic expansion valve, D 2 is the differential coefficient of the opening degree control of the electronic expansion valve, and τ, τ - 1, and τ - 2 represent time τ, time τ - 1, and time τ - 2 respectively.

[0112] Calculating the opening degree of the electronic expansion valve based on the opening degree increment of the electronic expansion valve.

[0113] Specifically, the following formula is used to calculate the opening degree of the electronic expansion valve:

[0114] E(τ) = E(τ - 1) + ΔE(τ); where E(τ) is the opening of the electronic expansion valve at time τ, E(τ - 1) is the opening of the electronic expansion valve at time τ - 1, and ΔE(τ) is the increment of the opening of the electronic expansion valve at time τ.

[0115] S240. Calculate the evaporator fan speed according to the evaporator outlet air temperature, evaporation temperature, and variable frequency compressor suction pressure.

[0116] Optionally, calculating the evaporator fan speed according to the evaporator outlet air temperature, evaporation temperature, and variable frequency compressor suction pressure includes:

[0117] Calculate the control deviation of the evaporator fan speed according to the evaporator outlet air temperature, evaporation temperature, and variable frequency compressor suction pressure.

[0118] Specifically, the following formula is used to calculate the control deviation of the evaporator fan:

[0119] where e 3 (τ) is the control deviation of the evaporator fan speed at time (τ), T 9 is the evaporator outlet air temperature, T EVA is the evaporation temperature, and LP is the variable frequency compressor suction pressure.

[0120] Calculate the increment of the evaporator fan speed according to the control deviation of the evaporator fan.

[0121] Specifically, the following formula is used to calculate the increment of the evaporator fan speed:

[0122] ΔH(τ) = P 3 ·[e 3 (τ) - e 3 (τ - 1)] + I 3 ·e 3 (τ) + D 3 ·[e 3 (τ) - 2e 3 (τ - 1) + e 3 (τ - 2)];

[0123] T 0 ≥T≥T SV , t≥τ≥0; where ΔH(τ) is the increment of the evaporator fan speed at time τ, P 3 is the control proportional coefficient of the evaporator fan speed, I 3 is the control integral coefficient of the evaporator fan speed, D 3 is the control differential coefficient of the evaporator fan speed, and τ, τ - 1, τ - 2 represent time τ, time τ - 1, and time τ - 2 respectively.

[0124] Calculate the evaporator fan speed based on the increment of the evaporator fan speed.

[0125] Specifically, the following formula is used to calculate the evaporator fan speed:

[0126] H(τ) = H(τ - 1) + ΔH(τ); where H(τ) is the evaporator fan speed at time τ, H(τ - 1) is the evaporator fan speed at time τ - 1, and ΔH(τ) is the increment of the evaporator fan speed at time τ.

[0127] S250. Calculate the condenser fan speed based on the condenser inlet air temperature and the discharge pressure of the variable frequency compressor.

[0128] Optionally, calculating the condenser fan speed based on the condenser inlet air temperature and the discharge pressure of the variable frequency compressor includes:

[0129] Calculate the control deviation of the condenser fan speed based on the condenser inlet air temperature and the discharge pressure of the variable frequency compressor.

[0130] Specifically, the following formula is used to calculate the control deviation of the condenser fan speed:

[0131] where e 4 (τ) is the control deviation of the condenser fan speed at time τ, T 5 is the condenser inlet air temperature, and HP is the discharge pressure of the variable frequency compressor.

[0132] Calculate the increment of the condenser fan speed based on the control deviation of the condenser fan speed.

[0133] Specifically, the following formula is used to calculate the increment of the condenser fan speed:

[0134] ΔC(τ) = P 4 ·[e 4 (τ) - e 4 (τ - 1)] + I 4 ·e 4 (τ) + D 4 ·[e 4 (τ) - 2e 4 (τ - 1) + e 4 (τ - 2)];

[0135] T 0 ≥T≥T SV , t≥τ≥0; where ΔC(τ) is the increment of the condenser fan speed at time τ, P 4 is the proportional coefficient of the condenser fan speed control, I 4 is the integral coefficient of the condenser fan speed control, and D 4is the differential coefficient for controlling the condenser fan speed. τ, τ-1, and τ-2 represent the τ-th moment, the (τ - 1)-th moment, and the (τ - 2)-th moment respectively.

[0136] Calculate the condenser fan speed based on the increment of the condenser fan speed.

[0137] Specifically, the following formula is used to calculate the condenser fan speed:

[0138] C(τ) = C(τ - 1) + ΔC(τ); where C(τ) is the condenser fan speed at the τ-th moment, C(τ - 1) is the condenser fan speed at the (τ - 1)-th moment, and ΔC(τ) is the increment of the condenser fan speed at the τ-th moment.

[0139] S260. Based on the calculated variable-frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, control the actions of the variable-frequency compressor, electronic expansion valve, evaporator fan, and condenser fan of the environment test chamber to be controlled respectively.

[0140] The technical solution provided by the embodiments of the present invention, through the variable-frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, and based on the calculated variable-frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, control the actions of the variable-frequency compressor, electronic expansion valve, evaporator fan, and condenser fan of the environment test chamber to be controlled respectively, thereby improving the system operation reliability and reducing the system operation energy consumption.

[0141] Figure 3 It is a schematic structural diagram of an environment test chamber provided by an embodiment of the present invention. Refer to Figure 3 , the environment test chamber includes a box body, a control system, and a refrigeration system. The control system executes the linear cooling control method of the environment test chamber provided by any of the above embodiments.

[0142] The control system includes a display unit, a sensor unit, and a control unit. The sensor unit is arranged inside the box body, the display unit is arranged on the surface of the box body, and the control unit is arranged inside or outside the box body. The display unit and the sensor unit are electrically connected to the control unit respectively.

[0143] The refrigeration system is arranged inside the box body and includes a variable-frequency compressor 2, a condenser 3, a condenser fan 4, an electronic expansion valve 6, an evaporator 7, and an evaporator fan 8; the evaporator 7, the electronic expansion valve 6, the condenser 3, and the variable-frequency compressor 2 are connected in series in sequence to form a loop.

[0144] The sensor unit includes an in-box temperature sensor 1, a condenser inlet air temperature sensor 5, an evaporator outlet air temperature sensor 9, a compressor suction pressure sensor 10, and a compressor discharge pressure sensor 11; the compressor suction pressure sensor 10 and the compressor discharge pressure sensor 11 are respectively arranged at the inlet and outlet of the variable-frequency compressor 2; the condenser inlet air temperature sensor 5 is arranged at the inlet of the condenser 3; the evaporator outlet air temperature sensor 9 is arranged at the outlet of the evaporator 3.

[0145] The control unit includes an evaporator fan speed control module 12, a compressor speed control module 13, an electronic expansion valve opening control module 14, a condenser fan speed control module 15, and an acquisition and calculation control module 16; the evaporator fan speed control module 12 is electrically connected to the evaporator fan 8; the compressor speed control module 13 is electrically connected to the variable-frequency compressor 2; the electronic expansion valve opening control module 14 is electrically connected to the electronic expansion valve 6; the condenser fan speed control module 15 is electrically connected to the condenser fan 4; the acquisition and calculation control module 16 is electrically connected to the in-box temperature sensor 1.

[0146] Specifically, the acquisition and calculation control module 16 is configured to calculate the variable-frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed, and the condenser fan speed of the environmental test chamber to be controlled respectively according to the in-box temperature, the variable-frequency compressor suction pressure, the variable-frequency compressor discharge pressure, the evaporator outlet air temperature, the evaporation temperature, the condenser inlet air temperature, and the linear cooling rate; then generate corresponding control instructions based on the calculated variable-frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, and transmit the corresponding control instructions to the compressor speed control module 13, the electronic expansion valve opening control module 14, the evaporator fan speed control module 12, and the condenser fan speed control module 15 respectively, so that the compressor speed control module 13, the electronic expansion valve opening control module 14, the evaporator fan speed control module 12, and the condenser fan speed control module 15 control the variable-frequency compressor 2, the electronic expansion valve 6, the evaporator fan 8, and the condenser fan 4 of the environmental test chamber to perform corresponding actions respectively based on the control instructions, and realize the linear cooling control of the environmental test chamber.

[0147] The environmental test chamber provided by the embodiment of the present invention uses the linear cooling control method of the environmental test chamber in the above embodiment, so the environmental test chamber provided by the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be elaborated here.

[0148] It should be understood that various forms of processes shown above can be used, steps can be reordered, added, or deleted. For example, the steps described in the present invention can be executed in parallel, sequentially, or in different orders, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0149] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A linear temperature reduction control method for an environmental test chamber, characterized in that: include: Obtain the temperature inside the controlled environment test chamber, the suction pressure of the variable frequency compressor, the exhaust pressure of the variable frequency compressor, the evaporator outlet temperature, the evaporation temperature, the condenser inlet temperature and the linear cooling rate; According to the temperature inside the box, the suction pressure of the variable frequency compressor, the exhaust pressure of the variable frequency compressor, the evaporator outlet temperature, the evaporation temperature, the condenser inlet temperature and the linear cooling rate, the variable frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed and the condenser fan speed of the controlled environmental test box are calculated respectively; Based on the calculated speed of the variable frequency compressor, the opening of the electronic expansion valve, the speed of the evaporator fan and the speed of the condenser fan, the actions of the variable frequency compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the controlled environmental test box are controlled respectively.

2. The linear temperature reduction control method according to claim 1, characterized in that: The step of calculating the variable frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed and the condenser fan speed of the controlled environment test box according to the box temperature, the variable frequency compressor suction pressure, the variable frequency compressor exhaust pressure, the evaporator outlet temperature, the evaporation temperature, the condenser inlet temperature and the linear cooling rate includes: Calculating the speed of the variable frequency compressor according to the temperature in the box, the suction pressure of the variable frequency compressor and the linear temperature reduction rate; Calculating the opening of the electronic expansion valve according to the temperature inside the box, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature and the linear cooling rate; Calculating the evaporator fan speed according to the evaporator outlet air temperature, the evaporation temperature and the variable frequency compressor suction pressure; The condenser fan speed is calculated according to the condenser inlet air temperature and the variable frequency compressor exhaust pressure.

3. The linear temperature reduction control method according to claim 2, characterized in that: The calculating the speed of the variable frequency compressor according to the temperature in the box, the suction pressure of the variable frequency compressor and the linear temperature drop rate comprises: Calculating the speed control deviation of the variable frequency compressor according to the temperature in the box, the suction pressure of the variable frequency compressor and the linear temperature reduction rate; Calculating a speed increment of the variable frequency compressor according to the speed control deviation of the variable frequency compressor; The speed of the variable frequency compressor is calculated according to the speed increment of the variable frequency compressor.

4. The linear temperature reduction control method according to claim 2, characterized in that: The calculating the opening of the electronic expansion valve according to the temperature in the box, the air outlet temperature of the evaporator, the evaporation temperature, the preset starting temperature and the linear temperature drop rate comprises: Calculating the electronic expansion valve control deviation according to the temperature inside the box, the evaporator air outlet temperature, the evaporation temperature, the preset starting temperature and the linear cooling rate; Calculating the electronic expansion valve opening increment according to the electronic expansion valve control deviation; The electronic expansion valve opening is calculated according to the electronic expansion valve opening increment.

5. The linear temperature reduction control method according to claim 2, characterized in that: The calculating of the evaporator fan speed according to the evaporator outlet air temperature, the evaporation temperature and the variable frequency compressor suction pressure comprises: Calculating the evaporator fan speed control deviation according to the evaporator outlet air temperature, the evaporation temperature and the variable frequency compressor suction pressure; calculating an evaporator fan speed increment according to the evaporator fan control deviation; The evaporator fan speed is calculated according to the evaporator fan speed increment.

6. The linear temperature reduction control method according to claim 2, characterized in that: The calculating of the condenser fan speed according to the condenser inlet air temperature and the variable frequency compressor exhaust pressure comprises: Calculating the condenser fan speed control deviation according to the condenser inlet air temperature and the variable frequency compressor exhaust pressure; calculating a condenser fan speed increment according to the condenser fan speed control deviation; The condenser fan speed is calculated according to the condenser fan speed increment.

7. The linear temperature reduction control method according to claim 3, characterized in that: The calculating of the speed control deviation of the variable frequency compressor according to the temperature in the box, the suction pressure of the variable frequency compressor and the linear temperature drop rate comprises: The following formula is used to calculate the speed control deviation of the variable frequency compressor: Where T is the temperature inside the box, V is the linear cooling rate, LP is the suction pressure of the variable frequency compressor, τ is any time within the total cooling time t, and e1(τ) is the speed control deviation of the variable frequency compressor; Calculating the speed increment of the variable frequency compressor according to the speed control deviation of the variable frequency compressor comprises: The speed increment of the variable frequency compressor is calculated using the following formula: Wherein, ΔF(τ) is the speed increment of the variable frequency compressor at time τ, P1 is the proportional coefficient of the variable frequency compressor speed control, I1 is the integral coefficient of the variable frequency compressor speed control, D1 is the differential coefficient of the variable frequency compressor speed control, τ, τ-1, τ-2 represent the time τ, τ-1 and τ-2 respectively, T0 is the preset start time, T SV To set the end time; Calculating the speed of the variable frequency compressor according to the speed increment of the variable frequency compressor comprises: The speed of the variable frequency compressor is calculated using the following formula: F(τ)=F(τ-1)+ΔF(τ); wherein, F(τ) is the speed of the variable frequency compressor at time τ, F(τ-1) is the speed of the variable frequency compressor at time τ-1, and ΔF(τ) is the speed increment of the variable frequency compressor at time τ.

8. The linear temperature reduction control method according to claim 4, characterized in that: The calculating of the electronic expansion valve control deviation according to the temperature in the box, the evaporator air outlet temperature, the evaporation temperature, the preset starting temperature and the linear temperature drop rate comprises: The electronic expansion valve control deviation is calculated using the following formula: Where, e2(τ) is the electronic expansion valve control deviation at time τ, T9 is the evaporator outlet air temperature, T EVA is the evaporation temperature, T0 is the preset starting temperature, T is the temperature inside the box, and V is the linear cooling rate; Calculating the electronic expansion valve opening increment according to the electronic expansion valve control deviation comprises: The electronic expansion valve opening increment is calculated using the following formula: Wherein, ΔE(τ) is the increment of the opening degree of the electronic expansion valve at time τ, P2 is the proportional coefficient of the opening degree control of the electronic expansion valve, I2 is the integral coefficient of the opening degree control of the electronic expansion valve, D2 is the differential coefficient of the opening degree control of the electronic expansion valve, τ, τ-1, τ-2 represent the time τ, the time τ-1 and the time τ-2 respectively; Calculating the opening of the electronic expansion valve according to the opening increment of the electronic expansion valve comprises: The opening of the electronic expansion valve is calculated using the following formula: E(τ)=E(τ-1)+ΔE(τ); wherein E(τ) is the opening of the electronic expansion valve at time τ, E(τ-1) is the opening of the electronic expansion valve at time τ-1, and ΔE(τ) is the increment of the opening of the electronic expansion valve at time τ.

9. The linear temperature reduction control method according to claim 5, characterized in that: The calculating of the evaporator fan speed control deviation according to the evaporator outlet air temperature, the evaporation temperature and the variable frequency compressor suction pressure comprises: The evaporator fan control deviation is calculated using the following formula: Where, e3(τ) is the evaporator fan speed control deviation at time (τ), T9 is the evaporator outlet air temperature, T EVA is the evaporation temperature, LP is the suction pressure of the variable frequency compressor; The step of calculating the evaporator fan speed increment according to the evaporator fan control deviation comprises: The evaporator fan speed increment is calculated using the following formula: Wherein, ΔH(τ) is the increment of the evaporator fan speed at time τ, P3 is the proportional coefficient of the evaporator fan speed control, I3 is the integral coefficient of the evaporator fan speed control, D3 is the differential coefficient of the evaporator fan speed control, τ, τ-1, τ-2 represent the time τ, time τ-1 and time τ-2 respectively; The calculating the evaporator fan speed according to the evaporator fan speed increment comprises: Use the following formula to calculate the evaporator fan speed: H(τ)=H(τ-1)+ΔH(τ); wherein H(τ) is the evaporator fan speed at time τ, H(τ-1) is the evaporator fan speed at time τ-1, and ΔH(τ) is the evaporator fan speed increment at time τ.

10. The linear temperature reduction control method according to claim 6, characterized in that: The calculating of the condenser fan speed control deviation according to the condenser inlet air temperature and the variable frequency compressor exhaust pressure comprises: The condenser fan speed control deviation is calculated using the following formula: Where, e4(τ) is the condenser fan speed control deviation at time τ, T5 is the condenser inlet air temperature, and HP is the variable frequency compressor exhaust pressure; The calculating the condenser fan speed increment according to the condenser fan speed control deviation comprises: The condenser fan speed increment is calculated using the following formula: Wherein, ΔC(τ) is the increment of the condenser fan speed at time τ, P4 is the proportional coefficient of the condenser fan speed control, I4 is the integral coefficient of the condenser fan speed control, D4 is the differential coefficient of the condenser fan speed control, τ, τ-1, τ-2 represent the time τ, τ-1 and τ-2 respectively; Calculating the condenser fan speed according to the condenser fan speed increment includes: Use the following formula to calculate the condenser fan speed: C(τ)=C(τ-1)+ΔC(τ); wherein, C(τ) is the condenser fan speed at time τ, C(τ-1) is the condenser fan speed at time τ-1, and ΔC(τ) is the condenser fan speed increment at time τ.

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