Linear cooling control method of environmental test chamber

Abstract

The application discloses a linear cooling control method of an environmental test chamber, and comprises the following steps: obtaining the temperature in the chamber, the suction pressure of a variable frequency compressor, the exhaust pressure of the variable frequency compressor, the outlet air temperature of an evaporator, the evaporation temperature, the inlet air temperature of a condenser and the linear cooling rate of a to-be-controlled environmental test chamber; calculating 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 environmental test chamber respectively according to the temperature in the chamber, 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; and controlling the variable frequency compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the to-be-controlled environmental test chamber to act respectively based on the calculated rotating speed of the variable frequency compressor, the opening degree of the electronic expansion valve, the rotating speed of the evaporator fan and the rotating speed of the condenser fan. The technical problem of high energy consumption of the compressor and poor system operation reliability in the prior art is solved.

Description

TECHNICAL FIELD

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

[0002] With the increasing progress of life and technology, the requirement for product reliability is higher and higher. In many fields, it is necessary to test the reliability, material stress change, material property change and the like of a product or a part during the process of decreasing from high temperature to low temperature according to a certain time.

[0003] During the linear cooling process, the refrigerating capacity requirement increases with the decrease of temperature. Moreover, the evaporating temperature also needs to be decreased with the decrease of temperature, and when the condensing temperature is constant, the compressor refrigerating capacity decreases with the decrease of evaporating temperature. Therefore, the compressor capacity exerted from the beginning to the end of the linear cooling process is quite different.

[0004] At present, a fixed-frequency compressor is mostly used in the linear cooling. The compressor is selected according to the maximum refrigerating capacity requirement of the linear cooling process, which causes the high overall compressor energy consumption in the linear cooling process. In addition, the control of the evaporator fan and the condenser fan is also crucial in the linear cooling process. When the air volume of the evaporator fan and the condenser fan is small, the system operation reliability and the refrigerating capacity exerted are affected, and when the air volume is large, the energy saving is poor.

[0005] Therefore, it is crucial to optimize the system control and operation in the linear cooling process for improving the system operation reliability and reducing the system operation energy consumption. SUMMARY

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

[0007] According to an aspect of the present application, a linear cooling control method of an environmental test chamber is provided, comprising:

[0008] obtaining the temperature in the chamber, the suction pressure of a variable-frequency compressor, the discharge pressure of the variable-frequency compressor, the outlet air temperature of an evaporator, the evaporating temperature, the inlet air temperature of a condenser and the linear cooling rate of a to-be-controlled environmental test chamber;

[0009] calculating the variable-frequency compressor rotating speed, the electronic expansion valve opening degree, the evaporator fan rotating speed and the condenser fan rotating speed of the to-be-controlled environmental test chamber according to the temperature in 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 evaporating temperature, the inlet air temperature of the condenser and the linear cooling rate;

[0010] Controlling the variable frequency compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the environmental test chamber according to the calculated variable frequency compressor rotating speed, the electronic expansion valve opening, the evaporator fan rotating speed and the condenser fan rotating speed respectively.

[0011] Optionally, the calculating the variable frequency compressor rotating speed, the electronic expansion valve opening, the evaporator fan rotating speed and the condenser fan rotating speed of the environmental test chamber according to the chamber temperature, the variable frequency compressor suction pressure, the variable frequency compressor discharge pressure, the evaporator outlet temperature, the evaporating temperature, the condenser inlet temperature and the linear cooling rate respectively comprises:

[0012] calculating the variable frequency compressor rotating speed according to the chamber temperature, the variable frequency compressor suction pressure and the linear cooling rate;

[0013] calculating the electronic expansion valve opening according to the chamber temperature, the evaporator outlet temperature, the evaporating temperature, the preset starting temperature and the linear cooling rate;

[0014] calculating the evaporator fan rotating speed according to the evaporator outlet temperature, the evaporating temperature and the variable frequency compressor suction pressure;

[0015] calculating the condenser fan rotating speed according to the condenser inlet temperature and the variable frequency compressor discharge pressure.

[0016] Optionally, the calculating the variable frequency compressor rotating speed according to the chamber temperature, the variable frequency compressor suction pressure and the linear cooling rate comprises:

[0017] calculating a variable frequency compressor rotating speed control deviation according to the chamber temperature, the variable frequency compressor suction pressure and the linear cooling rate;

[0018] calculating a variable frequency compressor rotating speed increment according to the variable frequency compressor rotating speed control deviation;

[0019] calculating the variable frequency compressor rotating speed according to the variable frequency compressor rotating speed increment.

[0020] Optionally, the calculating the electronic expansion valve opening according to the chamber temperature, the evaporator outlet temperature, the evaporating temperature, the preset starting temperature and the linear cooling rate comprises:

[0021] calculating an electronic expansion valve control deviation according to the chamber temperature, the evaporator outlet temperature, the evaporating temperature, the preset starting temperature and the linear cooling rate;

[0022] calculating an electronic expansion valve opening increment according to the electronic expansion valve control deviation;

[0023] calculating the electronic expansion valve opening degree according to the electronic expansion valve opening degree increment.

[0024] Optionally, the calculating the evaporator fan rotating speed according to the evaporator outlet air temperature, the evaporating temperature and the variable frequency compressor suction pressure comprises:

[0025] calculating an evaporator fan rotating speed control deviation according to the evaporator outlet air temperature, the evaporating temperature and the variable frequency compressor suction pressure;

[0026] calculating an evaporator fan rotating speed increment according to the evaporator fan control deviation;

[0027] calculating the evaporator fan rotating speed according to the evaporator fan rotating speed increment.

[0028] Optionally, the calculating the condenser fan rotating speed according to the condenser inlet air temperature and the variable frequency compressor discharge pressure comprises:

[0029] calculating a condenser fan rotating speed control deviation according to the condenser inlet air temperature and the variable frequency compressor discharge pressure;

[0030] calculating a condenser fan rotating speed increment according to the condenser fan rotating speed control deviation;

[0031] calculating the condenser fan rotating speed according to the condenser fan rotating speed increment.

[0032] Optionally, the calculating the variable frequency compressor rotating speed control deviation according to the indoor temperature, the variable frequency compressor suction pressure and the linear temperature reduction rate comprises:

[0033] calculating the variable frequency compressor rotating speed control deviation by using the following formula:

[0034] wherein, T is the indoor temperature, V is the linear temperature reduction rate, LP is the variable frequency compressor suction pressure, τ is an arbitrary time within the total temperature reduction time t, and e1(τ) is the variable frequency compressor rotating speed control deviation;

[0035] the calculating the variable frequency compressor rotating speed increment according to the variable frequency compressor rotating speed control deviation comprises:

[0036] calculating the variable frequency compressor rotating speed increment by using the following formula:

[0037] ΔF(τ)=P1·[e1(τ)-e1(τ-1)]+I1·e1(τ)+D1·[e1(τ)-2e1(τ-1)+e1(τ-2)];

[0038] T0≥T≥T SV, t≥τ≥0; wherein, ΔF(τ) is the rotational speed increment of the variable frequency compressor at time τ, P1 is the proportional coefficient of the rotational speed control of the variable frequency compressor, I1 is the integral coefficient of the rotational speed control of the variable frequency compressor, D1 is the differential coefficient of the rotational speed control of the variable frequency compressor, τ, τ-1 and τ-2 respectively represent time τ, time τ-1 and time τ-2, T0 is the preset starting time, T SV is the preset ending time;

[0039] The variable frequency compressor rotational speed is calculated according to the variable frequency compressor rotational speed increment.

[0040] The variable frequency compressor rotational speed is calculated according to the following formula:

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

[0042] The electronic expansion valve control deviation is calculated according to the indoor temperature, the evaporator outlet air temperature, the evaporating temperature, the preset starting temperature and the linear cooling rate.

[0043] The electronic expansion valve control deviation is calculated according to the following formula:

[0044] wherein, e2(τ) is the electronic expansion valve control deviation at time τ, T9 is the evaporator outlet air temperature, T EVA is the evaporating temperature, T0 is the preset starting temperature, T is the indoor temperature, and V is the linear cooling rate.

[0045] The electronic expansion valve opening increment is calculated according to the electronic expansion valve control deviation.

[0046] The electronic expansion valve opening increment is calculated according to the following formula:

[0047] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+e2(τ-2)];

[0048] T0≥T≥T SV , t≥τ≥0; wherein, ΔE(τ) is the electronic expansion valve opening increment at time τ, P2 is the proportional coefficient of the opening control of the electronic expansion valve, I2 is the integral coefficient of the opening control of the electronic expansion valve, and D2 is the differential coefficient of the opening control of the electronic expansion valve.

[0049] The electronic expansion valve opening is calculated according to the electronic expansion valve opening increment.

[0050] The electronic expansion valve opening degree is calculated by the following formula:

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

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

[0053] The evaporator fan control deviation is calculated by the following formula:

[0054] wherein, e3(τ) is the evaporator fan speed control deviation at (τ) time, T9 is the evaporator outlet air temperature, T EVA is the evaporating temperature, and LP is the variable frequency compressor suction pressure;

[0055] The calculation of the evaporator fan speed increment according to the evaporator fan control deviation comprises:

[0056] The evaporator fan speed increment is calculated by the following formula:

[0057] ΔH(τ) = P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+e3(τ-2)];

[0058] T0≥T≥T SV , t≥τ≥0; wherein, ΔH(τ) is the evaporator fan speed increment at τ time, P3 is the evaporator fan speed control proportional coefficient, I3 is the evaporator fan speed control integral coefficient, D3 is the evaporator fan speed control differential coefficient, τ, τ-1, and τ-2 respectively represent τ time, τ-1 time, and τ-2 time;

[0059] The calculation of the evaporator fan speed according to the evaporator fan speed increment comprises:

[0060] The evaporator fan speed is calculated by the following formula:

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

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

[0063] The condenser fan speed control deviation is calculated using the following formula:

[0064] In the formula, 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 discharge pressure.

[0065] The condenser fan speed control deviation is calculated using the following formula:

[0066] The condenser fan speed control deviation is calculated using the following formula:

[0067] ΔC(τ) = P4·[e4(τ) - e4(τ-1)] + I4·e4(τ) + D4·[e4(τ) - 2e4(τ-1) + e4(τ-2)];

[0068] T0≥T≥T SV , t≥τ≥0; In the formula, ΔC(τ) is the condenser fan speed increment at time τ, P4 is the condenser fan speed control proportional coefficient, I4 is the condenser fan speed control integral coefficient, D4 is the condenser fan speed control differential coefficient, τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

[0069] The condenser fan speed control deviation is calculated using the following formula:

[0070] The condenser fan speed control deviation is calculated using the following formula:

[0071] C(τ) = C(τ-1) + ΔC(τ); In the formula, 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.

[0072] The embodiment of the present application provides a linear cooling control method of an environmental test chamber, comprising: obtaining the temperature in a chamber of a to-be-controlled environmental test chamber, suction pressure of a variable frequency compressor, exhaust pressure of the variable frequency compressor, evaporator air outlet temperature, evaporation temperature, condenser air inlet temperature and linear cooling rate; calculating the variable frequency compressor rotating speed, electronic expansion valve opening degree, evaporator fan rotating speed and condenser fan rotating speed of the to-be-controlled environmental test chamber respectively according to the temperature in the chamber, the suction pressure of the variable frequency compressor, the exhaust pressure of the variable frequency compressor, the evaporator air outlet temperature, the evaporation temperature, the condenser air inlet temperature and the linear cooling rate; and controlling the variable frequency compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the to-be-controlled environmental test chamber to act respectively based on the calculated variable frequency compressor rotating speed, electronic expansion valve opening degree, evaporator fan rotating speed and condenser fan rotating speed. The technical scheme provided by the embodiment of the present application 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 by accurately calculating the variable frequency compressor rotating speed, the electronic expansion valve opening degree, the evaporator fan rotating speed and the condenser fan rotating speed and controlling the corresponding mechanisms by using the calculation results, and realizes the technical effects of improving the stability of the linear cooling control of the environmental test chamber and the system operation reliability and reducing the compressor energy consumption and the fan energy consumption.

[0073] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0074] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0075] Figure 1 A flow chart of a linear cooling control method of an environmental test chamber provided by the embodiment of the present application is shown in the figure.

[0076] Figure 2 A flow chart of another linear cooling control method of an environmental test chamber provided by the embodiment of the present application is shown in the figure.

[0077] Figure 3 A structure schematic diagram of an environmental test chamber provided by the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0078] In the following, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, so that those skilled in the art can better understand the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work should belong to the protection scope of the present application.

[0079] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0080] Figure 1 A flow chart of a linear cooling control method of an environmental test chamber according to an embodiment of the present application is shown in FIG. 1. Figure 1 The method comprises the following steps.

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

[0082] The 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, the product can be tested under the set environmental conditions for a period of time to understand the possible situations the product may face in actual use environment, so as to improve and optimize the product.

[0083] Specifically, the temperature sensor in the box, the condenser inlet air temperature sensor, the evaporator outlet air temperature sensor, the compressor suction pressure sensor and the compressor discharge pressure sensor are arranged in the test chamber, and the temperature in the test chamber, the frequency conversion compressor suction pressure, the frequency conversion compressor discharge pressure, the evaporator outlet air temperature, the evaporating temperature and the condenser inlet air temperature can be obtained by the temperature sensor in the box, the condenser inlet air temperature sensor, the evaporator outlet air temperature sensor, the compressor suction pressure sensor and the compressor discharge pressure sensor. The evaporating temperature and the linear cooling rate can be calculated, the evaporating temperature can be calculated by the compressor suction pressure, and the linear cooling rate can be calculated by the preset initial temperature, the preset final temperature and the preset total cooling time.

[0084] S120, according to the temperature in the box, the frequency conversion compressor suction pressure, the frequency conversion compressor discharge pressure, the evaporator outlet air temperature, the evaporating temperature, the condenser inlet air temperature and the linear cooling rate, the frequency conversion compressor speed, the electronic expansion valve opening, the evaporator fan speed and the condenser fan speed of the test chamber are calculated respectively.

[0085] Specifically, after obtaining the temperature in the box, the frequency conversion compressor suction pressure, the frequency conversion compressor discharge pressure, the evaporator outlet air temperature, the evaporating temperature, the condenser inlet air temperature and the linear cooling rate, the frequency conversion compressor, the electronic expansion valve, the evaporator fan and the condenser fan are calculated respectively by the frequency conversion compressor speed formula, the electronic expansion valve opening formula, the evaporator fan speed formula and the condenser fan speed formula.

[0086] S130, based on the calculated frequency conversion compressor speed, electronic expansion valve opening, evaporator fan speed and condenser fan speed, the frequency conversion compressor, electronic expansion valve, evaporator fan and condenser fan of the test chamber are controlled respectively.

[0087] Specifically, the calculated variable frequency compressor speed, the calculated electronic expansion valve opening degree, the calculated evaporator fan speed and the calculated condenser fan speed are used to control the variable frequency compressor, the electronic expansion valve, the evaporator fan and the condenser fan of the controlled environment test chamber.

[0088] The technical scheme provided by the embodiment of the present application solves the technical problems of high compressor energy consumption and poor system operation reliability in the linear cooling process of the existing environment test chamber by accurately calculating the variable frequency compressor speed, the electronic expansion valve opening degree, the evaporator fan speed and the condenser fan speed and using the calculation results to control the corresponding mechanisms, and achieves the technical effects of improving the stability of the linear cooling control of the environment test chamber and the system operation reliability and reducing the compressor energy consumption and the fan energy consumption.

[0089] Figure 2 The flowchart of another linear cooling control method of an environment test chamber provided by the embodiment of the present application is based on the above-mentioned embodiment and further refines the above-mentioned embodiment. Figure 2 The method comprises the following steps of:

[0090] S210, obtaining the temperature in 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 evaporating temperature, the inlet air temperature of the condenser and the linear cooling rate of the controlled environment test chamber.

[0091] S220, calculating the variable frequency compressor speed according to the temperature in the chamber, the suction pressure of the variable frequency compressor and the linear cooling rate.

[0092] Optionally, calculating the variable frequency compressor speed according to the temperature in the chamber, the suction pressure of the variable frequency compressor and the linear cooling rate comprises the following steps of:

[0093] calculating the variable frequency compressor speed control deviation according to the temperature in the chamber, the suction pressure of the variable frequency compressor and the linear cooling rate.

[0094] Specifically, the variable frequency compressor speed control deviation is calculated using the following formula:

[0095] In the formula, T is the temperature in the box, V is the linear cooling rate, LP is the variable frequency compressor suction pressure, τ is any time within the total cooling time t, and e1(τ) is the variable frequency compressor speed control deviation.

[0096] The variable frequency compressor speed increment is calculated according to the variable frequency compressor speed control deviation.

[0097] Specifically, the variable frequency compressor speed increment is calculated using the following formula:

[0098] ΔF(τ)=P1·[e1(τ)-e1(τ-1)]+I1·e1(τ)+D1·[e1(τ)-2e1(τ-1)+e1(τ-2)];

[0099] T0≥T≥T SV , t≥τ≥0; in the formula, ΔF(τ) is the variable frequency compressor speed increment at time τ, P1 is the variable frequency compressor speed control proportional coefficient, I1 is the variable frequency compressor speed control integral coefficient, D1 is the variable frequency compressor speed control differential coefficient, τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively, T0 is the preset starting time, T SV is the preset ending time.

[0100] The variable frequency compressor speed is calculated according to the variable frequency compressor speed increment.

[0101] Specifically, the variable frequency compressor speed is calculated using the following formula:

[0102] F(τ)=F(τ-1)+ΔF(τ); in the formula, 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.

[0103] S230, according to the temperature in the box, the evaporator outlet air temperature, the evaporation temperature, the preset starting temperature, and the linear cooling rate, the electronic expansion valve opening degree is calculated.

[0104] Optionally, calculating the electronic expansion valve opening degree according to the temperature in the box, the evaporator outlet air temperature, the evaporation temperature, the preset starting temperature, and the linear cooling rate includes:

[0105] According to the temperature in the box, the evaporator outlet air temperature, the evaporation temperature, the preset starting temperature, and the linear cooling rate, the electronic expansion valve control deviation is calculated.

[0106] Specifically, the electronic expansion valve control deviation is calculated using the following formula:

[0107] In the formula, e2(τ) is the electronic expansion valve control deviation at time τ, T9 is the evaporator outlet air temperature, T EVA is the evaporating temperature, T0 is the preset starting temperature, T is the tank temperature, and V is the linear cooling rate.

[0108] The electronic expansion valve opening increment is calculated according to the electronic expansion valve control deviation.

[0109] Specifically, the electronic expansion valve opening increment is calculated by the following formula:

[0110] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+e2(τ-2)];

[0111] T0≥T≥T SV , t≥τ≥0; in the formula, ΔE(τ) is the electronic expansion valve opening increment at time τ, P2 is the electronic expansion valve opening control proportional coefficient, I2 is the electronic expansion valve opening control integral coefficient, D2 is the electronic expansion valve opening control differential coefficient, τ, τ-1, and τ-2 represent τ time, τ-1 time, and τ-2 time respectively.

[0112] The electronic expansion valve opening is calculated according to the electronic expansion valve opening increment.

[0113] Specifically, the electronic expansion valve opening is calculated by the following formula:

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

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

[0116] Optionally, the evaporator fan speed is calculated according to the evaporator outlet air temperature, the evaporating temperature, and the variable frequency compressor suction pressure, comprising:

[0117] The evaporator fan speed control deviation is calculated according to the evaporator outlet air temperature, the evaporating temperature, and the variable frequency compressor suction pressure.

[0118] Specifically, the evaporator fan control deviation is calculated by the following formula:

[0119] In the formula, e3(τ) is the evaporator fan speed control deviation at time (τ), T9 is the evaporator outlet air temperature, T EVA is the evaporating temperature, and LP is the variable frequency compressor suction pressure.

[0120] The evaporator fan speed increment is calculated according to the evaporator fan control deviation.

[0121] Specifically, the evaporator fan speed increment is calculated by the following formula:

[0122] ΔH(τ) = P3·[e3(τ) - e3(τ-1)] + I3·e3(τ) + D3·[e3(τ) - 2e3(τ-1) + e3(τ-2)];

[0123] T0≥T≥T SV , t≥τ≥0; in the formula, ΔH(τ) is the evaporator fan speed increment at τ moment, P3 is the evaporator fan speed control proportional coefficient, I3 is the evaporator fan speed control integral coefficient, D3 is the evaporator fan speed control differential coefficient, τ, τ-1 and τ-2 respectively represent τ moment, τ-1 moment and τ-2 moment.

[0124] The evaporator fan speed is calculated according to the evaporator fan speed increment.

[0125] Specifically, the evaporator fan speed is calculated by the following formula:

[0126] H(τ) = H(τ-1) + ΔH(τ); in the formula, H(τ) is the evaporator fan speed at τ moment, H(τ-1) is the evaporator fan speed at τ-1 moment, and ΔH(τ) is the evaporator fan speed increment at τ moment.

[0127] S250, the condenser fan speed is calculated according to the condenser inlet air temperature and the variable frequency compressor discharge pressure.

[0128] Optionally, the condenser fan speed is calculated according to the condenser inlet air temperature and the variable frequency compressor discharge pressure, comprising:

[0129] The condenser fan speed control deviation is calculated according to the condenser inlet air temperature and the variable frequency compressor discharge pressure.

[0130] Specifically, the condenser fan speed control deviation is calculated by the following formula:

[0131] In the formula, e4(τ) is the condenser fan speed control deviation at τ moment, T5 is the condenser inlet air temperature, and HP is the variable frequency compressor discharge pressure.

[0132] The condenser fan speed increment is calculated according to the condenser fan speed control deviation.

[0133] Specifically, the condenser fan speed increment is calculated by the following formula:

[0134] ΔC(τ)=P4·[e4(τ)-e4(τ-1)]+I4·e4(τ)+D4·[e4(τ)-2e4(τ-1)+e4(τ-2)];

[0135] T0≥T≥T SV , t≥τ≥0; where ΔC(τ) is the condenser fan speed increment at time τ, P4 is the condenser fan speed control proportional coefficient, I4 is the condenser fan speed control integral coefficient, D4 is the condenser fan speed control differential coefficient, and τ, τ-1, and τ-2 represent time τ, time τ-1, and time τ-2, respectively.

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

[0137] Specifically, the condenser fan speed is calculated using the following formula:

[0138] C(τ)=C(τ-1)+ΔC(τ); where 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.

[0139] S260 controls the operation of the variable frequency compressor, electronic expansion valve, evaporator fan speed, and condenser fan of the environmental test chamber based on the calculated variable frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed.

[0140] The technical solution provided by this invention improves system reliability and reduces system energy consumption by controlling the operation of the variable frequency compressor, electronic expansion valve, evaporator fan, and condenser fan in the test chamber based on the calculated variable frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed.

[0141] Figure 3 This is a structural schematic diagram of an environmental test chamber provided in an embodiment of the present invention. See also: Figure 3 The environmental test chamber includes a chamber body, a control system, and a refrigeration system. The control system executes the linear cooling control method for the environmental test chamber provided in any of the above embodiments.

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

[0143] The refrigeration system is arranged in the cabinet and comprises 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 sequentially connected in series to form a loop.

[0144] The sensor unit comprises an in-cabinet 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 arranged at the inlet and outlet of the variable frequency compressor 2 respectively; the condenser inlet air temperature sensor 5 is arranged at the air inlet of the condenser 3; and the evaporator outlet air temperature sensor 9 is arranged at the air outlet of the evaporator 3.

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

[0146] Specifically, the collection and calculation control module 16 is used to calculate the variable frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed and the condenser fan speed of the controlled environmental test chamber respectively according to the in-cabinet temperature, the variable frequency compressor suction pressure, the variable frequency compressor discharge pressure, the evaporator outlet air temperature, the evaporating temperature, the condenser inlet air temperature and the linear cooling rate; then corresponding control instructions are generated based on the calculated variable frequency compressor speed, the electronic expansion valve opening, the evaporator fan speed and the condenser fan speed, and the corresponding control instructions are transmitted 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 based on the control instructions, so as to realize the linear cooling control of the environmental test chamber.

[0147] The environmental test chamber provided by the embodiment of the present application 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 application also has the beneficial effects described in the above embodiment, which will not be repeated here.

[0148] It should be understood that the various forms of flow shown above can be used to reorder, add, or remove steps. For example, the steps recited in the present application can be performed in parallel, in series, or in a different order, as long as the desired results of the technical solutions of the present application can be achieved, which are not limited herein.

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

Claims

1. A linear cooling control method of an environmental test chamber, characterized by, The method comprises: acquiring the temperature in the test chamber, the suction pressure of the variable frequency compressor, the discharge pressure of the variable frequency compressor, the temperature of the evaporator outlet air, the evaporating temperature, the temperature of the condenser inlet air, and the linear cooling rate; calculating the variable frequency compressor speed control deviation according to the temperature in the test chamber, the suction pressure of the variable frequency compressor, and the linear cooling rate; calculating the variable frequency compressor speed increment according to the variable frequency compressor speed control deviation; calculating the variable frequency compressor speed according to the variable frequency compressor speed increment; calculating the variable frequency compressor speed control deviation by using the following formula: wherein, Tbox is the temperature inside the box, is the linear cooling rate, is the suction pressure of the variable frequency compressor, is the arbitrary time within the total cooling time t, is the variable frequency compressor speed control deviation; calculating the electronic expansion valve control deviation according to the temperature in the test chamber, the temperature of the evaporator outlet air, the evaporating temperature, the preset initial temperature, and the linear cooling rate; calculating the electronic expansion valve opening increment according to the electronic expansion valve control deviation; calculating the electronic expansion valve opening according to the electronic expansion valve opening increment; calculating the electronic expansion valve control deviation by using the following formula: ; wherein is is an electronic expansion valve control deviation at the moment, is an evaporator outlet air temperature, is an evaporation temperature, is a preset initial temperature, is a tank temperature, is a linear cooling rate; calculating the evaporator fan speed control deviation according to the temperature of the evaporator outlet air, the evaporating temperature, and the suction pressure of the variable frequency compressor; calculating the evaporator fan speed increment according to the evaporator fan control deviation; calculating the evaporator fan speed according to the evaporator fan speed increment; calculating the evaporator fan control deviation by using the following formula: ; wherein is a control deviation of the evaporator fan speed at the moment, is the evaporator outlet air temperature, is the evaporating temperature, is the variable frequency compressor suction pressure; calculating the condenser fan speed control deviation according to the temperature of the condenser inlet air and the discharge pressure of the variable frequency compressor; calculating the condenser fan speed increment according to the condenser fan speed control deviation; calculating the condenser fan speed according to the condenser fan speed increment; calculating the condenser fan speed control deviation by using the following formula: ; wherein is a condenser fan speed control deviation at the time instant, is a condenser inlet air temperature, is a variable frequency compressor discharge pressure; controlling the variable frequency compressor, the electronic expansion valve, the evaporator fan, and the condenser fan of the test chamber to be controlled based on the calculated variable frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, respectively.

2. The linear demagnetization control method according to claim 1, characterized by, The method further comprises: calculating the variable frequency compressor speed increment by using the following formula: ; wherein is is the incremental value of the variable frequency compressor speed at the time point, is the proportional coefficient of the variable frequency compressor speed control, is the integral coefficient of the variable frequency compressor speed control, is the differential coefficient of the variable frequency compressor speed control, , , respectively represent the time point, the time point and the time point, is the preset starting time, is the preset ending time; The method further comprises: calculating the variable frequency compressor speed by using the following formula: wherein is the variable frequency compressor speed at the time instant, is the variable frequency compressor speed at the time instant, is the variable frequency compressor speed increment at the time instant.

3. The linear cooling control method according to claim 1, wherein The method further comprises: calculating the electronic expansion valve opening increment by using the following formula: wherein is an electronic expansion valve opening degree increment at the time point, is an electronic expansion valve opening degree control proportional coefficient, is an electronic expansion valve opening degree control integral coefficient, is an electronic expansion valve opening degree control differential coefficient, , , respectively represent a time point, a time point, and a time point; The method further comprises: calculating the electronic expansion valve opening by using the following formula: wherein is the electronic expansion valve opening at the time point, is the electronic expansion valve opening at the time point, is the electronic expansion valve opening increment at the time point.

4. The linear cooling control method according to claim 1, wherein The method further comprises: calculating the evaporator fan speed increment by using the following formula: ; wherein is an increment of the evaporator fan speed at the time t, is a proportional coefficient of the evaporator fan speed control, is an integral coefficient of the evaporator fan speed control, is a differential coefficient of the evaporator fan speed control, , , respectively represent the time t, the time t and the time t. The method further comprises: calculating the evaporator fan speed by using the following formula: wherein is the evaporator fan speed at the time instant, is the evaporator fan speed at the time instant, is the evaporator fan speed increment at the time instant.

5. The linear cooling control method according to claim 1, wherein The method further comprises: The condenser fan speed increment is calculated by the following formula: ; wherein is an incremental value of the condenser fan speed at the time t, is a proportional coefficient of the condenser fan speed control, is an integral coefficient of the condenser fan speed control, is a differential coefficient of the condenser fan speed control, , , respectively represent the time t, the time t and the time t. The condenser fan speed is calculated according to the condenser fan speed increment, and the calculation method comprises the following steps: The condenser fan speed is calculated by the following formula: wherein is the condenser fan speed at time t, is the condenser fan speed at time t, is the condenser fan speed increment at time t.

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