Cooling control method of test box and test box

Abstract

The embodiment of the invention discloses a cooling control method of a test box and the test box. The cooling control method comprises the following steps: acquiring the current temperature of the test box; determining a control deviation of the pulse electromagnetic valve based on the current temperature and a preset temperature parameter of the test box; determining the opening increment of the pulse electromagnetic valve based on the control deviation and the gain coefficient of the pulse electromagnetic valve; determining the opening degree of the pulse electromagnetic valve based on the opening degree increment of the pulse electromagnetic valve; determining the opening degree of the electronic expansion valve based on the opening degree of the pulse electromagnetic valve; and determining the rotating speed of an evaporator fan based on the superheat degree of the evaporator, the opening degree of the pulse electromagnetic valve and the opening degree of the electronic expansion valve so as to control the test box to cool. The technical problem that in the prior art, when linear cooling is carried out on a test box, the requirement for linear cooling at different rates cannot be met at the same time through single-path or multi-path arrangement of a throttling valve is solved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of temperature control technology, and in particular to a temperature reduction control method of a test box and a test box. Background Art

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

[0003] At present, linear cooling mostly uses fixed-frequency compressors. When the throttle valve uses an electronic expansion valve, the system structure is simple and the curve stability is good. However, due to the problem of its adjustment rate, the electronic expansion valve cannot perform linear cooling at a higher rate. When the linear cooling rate is required to be high, the throttle valve generally uses a multi-way combination. At this time, the system structure is complex, the curve stability is poor, and it cannot meet the low-rate linear cooling requirements. In addition, the control of the fan is also crucial. When the fan air volume is too small, the refrigerant in the evaporator cannot be completely evaporated. When the fan air volume is too large, the energy saving is poor. Summary of the invention

[0004] The embodiment of the present invention provides a test box temperature reduction control method and a test box, which solves the technical problem in the prior art that the test box cannot simultaneously meet the linear temperature reduction requirements of different rates through the single-channel or multi-channel setting of the throttle valve when performing linear temperature reduction.

[0005] An embodiment of the present invention provides a temperature reduction control method for a test chamber, the temperature reduction control method comprising:

[0006] Get the current temperature of the test chamber;

[0007] Determining a control deviation of the pulse solenoid valve based on the current temperature and preset temperature parameters of the test chamber, wherein the preset temperature parameters at least include a set starting temperature, a set target temperature, and a target cooling time of the test chamber;

[0008] Determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve, wherein the gain coefficient is obtained by querying a preset database, and the preset database stores a relationship table between the linear cooling rate of the test box, the control deviation of the pulse solenoid valve, and the gain coefficient;

[0009] determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve;

[0010] determining the opening of the electronic expansion valve based on the opening of the pulse solenoid valve;

[0011] The rotation speed of the evaporator fan is determined based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve to control the test box to cool down.

[0012] Further, determining the control deviation of the pulse solenoid valve based on the current temperature and the preset temperature parameter of the test box includes:

[0013] Using the formula Determine the control deviation of the pulse solenoid valve, where e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, t≥τ≥0, T is the current temperature, T0 is the set starting temperature, T SV A target temperature is set for the .

[0014] Further, determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve includes:

[0015] The opening increment ΔZ (τ) of the pulse solenoid valve is determined based on the following formula:

[0016] ΔZ(τ)=k·P1·[e1(τ)-e1(τ-1)]+k·I1·e1(τ)+k·D1·[e1(τ)-

[0017] 2e1(τ-1)+e1(τ-2)];

[0018] Among them, k is the gain coefficient, P1 is the proportional coefficient, I1 is the integral coefficient, D1 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e1(τ), e1(τ-1), e1(τ-2) are the control deviations of the pulse solenoid valve at τ, τ-1, τ-2 respectively.

[0019] Further, determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve includes:

[0020] The opening of the pulse solenoid valve is determined based on the formula Z(τ)=Z(τ-1)+ΔZ(τ), wherein Z(τ) is the opening of the pulse solenoid valve at time τ, Z(τ-1) is the opening of the pulse solenoid valve at time τ-1, and ΔZ(τ) is the opening increment of the pulse solenoid valve.

[0021] Further, determining the opening of the electronic expansion valve based on the opening of the pulse solenoid valve includes:

[0022] determining a control deviation of the electronic expansion valve based on the opening degree of the pulse solenoid valve;

[0023] determining an opening increment of the electronic expansion valve based on a control deviation of the electronic expansion valve;

[0024] The opening degree of the electronic expansion valve is determined based on the opening degree increment of the electronic expansion valve.

[0025] Further, determining the control deviation of the electronic expansion valve based on the opening of the pulse solenoid valve includes:

[0026] Using the formula e2(τ)=MIN[exp(e1(τ)), Y e ]·(Y Z ·sinZ) to determine the control deviation of the electronic expansion valve, wherein e2(τ) is the control deviation of the electronic expansion valve, e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, and Y e is the maximum gain coefficient of the opening degree of the electronic expansion valve, Y z is the opening equity coefficient of the pulse solenoid valve, and Z is the opening of the pulse solenoid valve.

[0027] Further, determining the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve includes:

[0028] The opening increment ΔE(τ) of the electronic expansion valve is determined based on the following formula:

[0029] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+

[0030] e2(τ-2)];

[0031] Among them, P2 is the proportional coefficient, I2 is the integral coefficient, D2 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e2(τ), e2(τ-1), e2(τ-2) are the control deviations of the electronic expansion valve at τ, τ-1, τ-2 respectively.

[0032] Further, determining the opening degree of the electronic expansion valve based on the opening degree increment of the electronic expansion valve includes:

[0033] The opening of the electronic expansion valve is determined based on the 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 opening increment of the electronic expansion valve.

[0034] Further, determining the rotation speed of the evaporator fan based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve includes:

[0035] When the superheat of the evaporator is less than or equal to the critical superheat, the speed of the evaporator fan is the maximum speed of the fan;

[0036] When the superheat of the evaporator is greater than the critical superheat, the speed of the evaporator fan is determined by the following method:

[0037] determining a control deviation of the evaporator fan based on the opening of the pulse solenoid valve and the opening of the electronic expansion valve;

[0038] determining a speed increment of the evaporator fan based on a control deviation of the evaporator fan;

[0039] The speed of the evaporator fan is determined based on the speed increment of the evaporator fan.

[0040] Further, determining the control deviation of the evaporator fan based on the opening of the pulse solenoid valve and the opening of the electronic expansion valve includes:

[0041] Using the formula Determine the control deviation of the evaporator fan, where e3(τ) is the control deviation of the evaporator fan, k0 is the superheat of the evaporator, k obj is the control target value of the evaporator superheat, τ is any time within the target cooling time t, T is the current temperature, T0 is the set starting temperature, T SV is the set target temperature, Z is the opening degree of the pulse solenoid valve, and E is the opening degree of the electronic expansion valve.

[0042] Further, determining the speed increment of the evaporator fan based on the control deviation of the evaporator fan includes:

[0043] The speed increment ΔH (τ) of the evaporator fan is determined based on the following formula:

[0044] ΔH(τ)=P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+

[0045] e3(τ-2)];

[0046] Among them, P3 is the proportional coefficient, I3 is the integral coefficient, D3 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e3(τ), e3(τ-1), e3(τ-2) are the control deviations of the evaporator fan at τ, τ-1, τ-2 respectively.

[0047] Further, determining the speed of the evaporator fan based on the speed increment of the evaporator fan includes:

[0048] The speed of the evaporator fan is determined based on the formula H(τ)=H(τ-1)+ΔH(τ), wherein H(τ) is the speed of the evaporator fan at time τ, H(τ-1) is the speed of the evaporator fan at time τ-1, and ΔH(τ) is the speed increment of the evaporator fan.

[0049] An embodiment of the present invention further provides a test box, the test box comprising a box body, a control system and a refrigeration system, the control system executing the temperature reduction control method of the test box described in any of the above embodiments;

[0050] The control system comprises a display unit, a sensor unit and a control unit, wherein the sensor unit is arranged in the box, the display unit is arranged on the surface of the box, the control unit is arranged in the box or outside the box, and the display unit and the sensor unit are electrically connected to the control unit respectively;

[0051] The refrigeration system is arranged in the box, and includes a compressor, a condenser, an evaporator, an evaporator fan, a pulse solenoid valve and an electronic expansion valve;

[0052] The evaporator, the electronic expansion valve, the pulse solenoid valve, the condenser and the compressor are connected in series in sequence to form a loop, and the evaporator fan is arranged at the evaporator.

[0053] Further, the sensor unit includes an in-box temperature sensor, an evaporator outlet temperature sensor, and an evaporator outlet pressure sensor;

[0054] The evaporator outlet temperature sensor is arranged at the outlet of the evaporator; the evaporator outlet pressure sensor is arranged at the outlet of the evaporator;

[0055] The control unit includes a fan speed control module, an electronic expansion valve opening control module, a pulse solenoid valve opening control module and a collection calculation control module;

[0056] The acquisition calculation control module is electrically connected to the sensor in the sensor unit, the fan speed control module, the electronic expansion valve opening control module, and the pulse solenoid valve opening control module respectively;

[0057] The fan speed control module is electrically connected to the evaporator fan;

[0058] The electronic expansion valve opening control module is electrically connected to the electronic expansion valve;

[0059] The pulse solenoid valve opening control module is electrically connected to the pulse solenoid valve.

[0060] The embodiment of the present invention discloses a cooling control method for a test box and a test box, the cooling control method comprising: obtaining the current temperature of the test box; determining the control deviation of a pulse solenoid valve based on the current temperature and a preset temperature parameter of the test box; determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve; determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve; determining the opening of the electronic expansion valve based on the opening of the pulse solenoid valve; determining the speed of the evaporator fan based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve, so as to control the cooling of the test box. The present application uses the control deviation of each valve to accurately calculate the opening of the pulse solenoid valve and the electronic expansion valve, and uses the opening of the pulse solenoid valve and the electronic expansion valve to determine the speed of the evaporator fan, which solves the technical problem that the test box in the prior art cannot simultaneously meet the linear cooling requirements of different rates through the single-channel or multi-channel setting of the throttle valve when performing linear cooling, and achieves the technical effects of improving the stability of the linear cooling temperature curve of the test box, increasing the cooling rate adaptation range of the test box, and reducing the operating energy consumption of the cooling system of the test box. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 is a structural diagram of a temperature reduction control method for a test box provided by an embodiment of the present invention;

[0062] Figure 2 is a structural diagram of another temperature reduction control method for a test chamber provided by an embodiment of the present invention;

[0063] Figure 3 is a structural diagram of another temperature reduction control method for a test chamber provided by an embodiment of the present invention;

[0064] Figure 4 It is a structural diagram of a test box provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0065] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0066] It should be noted that the terms "first", "second", etc. in the specification, claims and drawings of the present invention are used to distinguish different objects, rather than to limit a specific order. The following embodiments of the present invention can be implemented separately, or in combination with each other, and the embodiments of the present invention do not impose specific limitations on this.

[0067] Figure 1 It is a structural diagram of a temperature reduction control method for a test chamber provided in an embodiment of the present invention.

[0068] like Figure 1 As shown, the temperature reduction control method of the test chamber specifically includes the following steps:

[0069] S101, obtaining the current temperature of the test chamber;

[0070] Specifically, a control system is provided in the environmental test chamber, and the control system includes a display unit, a sensor unit and a control unit. The sensor unit includes an in-chamber temperature sensor, which can obtain the current temperature in the test chamber in real time.

[0071] S102, determining a control deviation of the pulse solenoid valve based on the current temperature and preset temperature parameters of the test chamber, wherein the preset temperature parameters at least include a set starting temperature, a set target temperature, and a target cooling time of the test chamber.

[0072] Optionally, S102 specifically includes:

[0073] Using the formula Determine the control deviation of the pulse solenoid valve, where e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, t≥τ≥0, T is the current temperature, T0 is the set starting temperature, T SV To set the target temperature.

[0074] S103, determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve, wherein the gain coefficient is obtained by querying a preset database, which stores a relationship table between the linear cooling rate of the test chamber, the control deviation of the pulse solenoid valve and the gain coefficient.

[0075] Specifically, the preset temperature parameters of the test chamber include the set starting temperature T0 of the test chamber, the set target temperature T SV And the target cooling time t. According to the preset temperature parameters, use the formula Determine the linear cooling rate V of the environmental test box to be controlled, and then establish a preset database based on the linear cooling rate V. The preset database stores a relationship table between the linear cooling rate V of the test box, the control deviation e1(τ) of the pulse solenoid valve, and the gain coefficient k. The relationship table can be a value obtained by experimental measurement or a theoretical analysis value, which is not specifically limited here. See Table 1, which is a relationship table between V, e1(τ) and k of a certain environmental test box, where i and j both represent numbers used to distinguish parameters. After querying the preset database to obtain the gain coefficient k, determine the opening increment ΔZ(τ) of the pulse solenoid valve based on the control deviation e1(τ) and gain coefficient k of the pulse solenoid valve.

[0076] Table 1. Relationship between V, e1(τ) and k of an environmental test chamber

[0077] <![CDATA[e1(τ)1]]> <![CDATA[e1(τ)2]]> … <![CDATA[e1(τ)j]]> <![CDATA[V1]]> <![CDATA[k 11 ]]> <![CDATA[k 12 ]]> … <![CDATA[k 1j ]]> <![CDATA[V2]]> <![CDATA[k 21 ]]> <![CDATA[k 22 ]]> … <![CDATA[k 2j ]]> … … … … … <![CDATA[V i ]]> <![CDATA[k i1 ]]> <![CDATA[k i2 ]]> … <![CDATA[k ij ]]>

[0078] Optionally, S103 specifically includes:

[0079] The opening increment ΔZ (τ) of the pulse solenoid valve is determined based on the following formula:

[0080] ΔZ(τ)=k·P1·[e1(τ)-e1(τ-1)]+k·I1·e1(τ)+k·D1·[e1(τ)-

[0081] 2e1(τ-1)+e1(τ-2)];

[0082] Among them, k is the gain coefficient, P1 is the proportional coefficient, I1 is the integral coefficient, D1 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e1(τ), e1(τ-1), e1(τ-2) are the control deviations of the pulse solenoid valve at τ, τ-1, τ-2 respectively.

[0083] S104, determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve.

[0084] Specifically, after obtaining the opening increment ΔZ(τ) of the pulse solenoid valve, the opening of the pulse solenoid valve at the previous moment and the opening increment ΔZ(τ) of the pulse solenoid valve are used to determine the opening of the pulse solenoid valve at the current moment.

[0085] Optionally, S104 specifically includes:

[0086] The opening of the pulse solenoid valve is determined based on the formula Z(τ)=Z(τ-1)+ΔZ(τ), where Z(τ) is the opening of the pulse solenoid valve at time τ, Z(τ-1) is the opening of the pulse solenoid valve at time τ-1, and ΔZ(τ) is the opening increment of the pulse solenoid valve.

[0087] S105, determining the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve.

[0088] Specifically, after obtaining the opening Z(τ) of the pulse solenoid valve, the opening Z(τ) of the pulse solenoid valve can be used to determine the control deviation e2(τ) of the electronic expansion valve, and then the control deviation e2(τ) of the electronic expansion valve can be used to determine the opening increment ΔE(τ) of the electronic expansion valve, and finally the opening increment ΔE(τ) of the electronic expansion valve can be used to determine the opening E(τ) of the electronic expansion valve.

[0089] S106, determining the rotation speed of the evaporator fan based on the superheat of the evaporator, the opening of the pulse solenoid valve, and the opening of the electronic expansion valve, so as to control the test box to cool down.

[0090] Specifically, after the opening Z(τ) of the pulse electromagnetic valve and the opening E(τ) of the electronic expansion valve are obtained, the speed H(τ) of the evaporator fan is comprehensively determined by considering the superheat k0 of the evaporator.

[0091] In an embodiment of the present invention, the openings of the pulse solenoid valve and the electronic expansion valve are accurately calculated by utilizing the control deviations of each valve, and the speed of the evaporator fan is determined by utilizing the openings of the pulse solenoid valve and the electronic expansion valve. This solves the technical problem in the prior art that the single-channel or multi-channel setting of the throttle valve during linear cooling of the test box cannot simultaneously meet the linear cooling requirements of different rates, thereby achieving the technical effects of improving the stability of the linear cooling temperature curve of the test box, increasing the cooling rate adaptability range of the test box, and reducing the operating energy consumption of the cooling system of the test box.

[0092] On the basis of the above technical solutions, Figure 2 is a structural diagram of another test box temperature reduction control method provided by an embodiment of the present invention, such as Figure 2 As shown, S105 specifically includes:

[0093] S201, determining a control deviation of the electronic expansion valve based on the opening degree of the pulse solenoid valve.

[0094] Optionally, S201, determining the control deviation of the electronic expansion valve based on the opening of the pulse solenoid valve includes:

[0095] Using the formula e2(τ)=MIN[exp(e1(τ)), Y e ]·(Y Z ·sinZ) to determine the control deviation of the electronic expansion valve, where e2(τ) is the control deviation of the electronic expansion valve, e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, and Y e is the maximum gain coefficient of the opening degree of the electronic expansion valve, Y z is the opening equity coefficient of the pulse solenoid valve, and Z is the opening of the pulse solenoid valve.

[0096] S202: Determine an opening increment of the electronic expansion valve based on a control deviation of the electronic expansion valve.

[0097] Optionally, S202, determining the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve includes:

[0098] The opening increment ΔE(τ) of the electronic expansion valve is determined based on the following formula:

[0099] ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+

[0100] e2(τ-2)];

[0101] Among them, P2 is the proportional coefficient, I2 is the integral coefficient, D2 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e2(τ), e2(τ-1), e2(τ-2) are the control deviations of the electronic expansion valve at τ, τ-1, τ-2 respectively.

[0102] S203: Determine the opening degree of the electronic expansion valve based on the opening degree increment of the electronic expansion valve.

[0103] Optionally, S203, determining the opening degree of the electronic expansion valve based on the opening degree increment of the electronic expansion valve includes:

[0104] The opening of the electronic expansion valve is determined based on the 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 opening increment of the electronic expansion valve.

[0105] On the basis of the above technical solutions, Figure 3 is a structural diagram of another test box temperature reduction control method provided by an embodiment of the present invention, such as Figure 3 As shown, S106 specifically includes:

[0106] S301, when the superheat of the evaporator is less than or equal to the critical superheat, the speed of the evaporator fan is the maximum speed of the fan.

[0107] Specifically, when the superheat k0 of the evaporator is less than or equal to the critical superheat k obj When the evaporator fan speed H(τ) is the maximum fan speed H max .

[0108] S302, when the superheat of the evaporator is greater than the critical superheat, the speed of the evaporator fan is determined by the following method:

[0109] S1, determining the control deviation of the evaporator fan based on the opening of the pulse solenoid valve and the opening of the electronic expansion valve.

[0110] Optionally, when the superheat k0 of the evaporator is greater than the critical superheat k obj When, step S1 specifically includes:

[0111] Using the formula Determine the control deviation of the evaporator fan, where e3(τ) is the control deviation of the evaporator fan, k0 is the superheat of the evaporator, and k obj is the control target value of the evaporator superheat, τ is any time within the target cooling time t, T is the current temperature, T0 is the set starting temperature, T SVTo set the target temperature, Z is the opening of the pulse solenoid valve, and E is the opening of the electronic expansion valve.

[0112] S2, determining a speed increment of the evaporator fan based on a control deviation of the evaporator fan.

[0113] Optionally, step S2 specifically includes:

[0114] The speed increment ΔH (τ) of the evaporator fan is determined based on the following formula:

[0115] ΔH(τ)=P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+

[0116] e3(τ-2)];

[0117] Among them, P3 is the proportional coefficient, I3 is the integral coefficient, D3 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e3(τ), e3(τ-1), e3(τ-2) are the control deviations of the evaporator fan at τ, τ-1, τ-2 respectively.

[0118] S3, determining the speed of the evaporator fan based on the speed increment of the evaporator fan.

[0119] Optionally, step S3 specifically includes:

[0120] The speed of the evaporator fan is determined based on the formula H(τ)=H(τ-1)+ΔH(τ), where H(τ) is the speed of the evaporator fan at time τ, H(τ-1) is the speed of the evaporator fan at time τ-1, and ΔH(τ) is the speed increment of the evaporator fan.

[0121] Figure 4 It is a structural diagram of a test box provided by an embodiment of the present invention.

[0122] An embodiment of the present invention further provides a test box, which includes a box body, a control system and a refrigeration system. The control system executes the temperature reduction control method of the test box in any of the above embodiments.

[0123] The control system includes a display unit, a sensor unit and a control unit. The sensor unit is arranged in the box, the display unit is arranged on the surface of the box, the control unit is arranged in the box or outside the box, and the display unit and the sensor unit are electrically connected to the control unit respectively;

[0124] The refrigeration system is arranged in the box, and includes a compressor 1, a condenser 2, an evaporator 3, an evaporator fan 4, a pulse solenoid valve 5 and an electronic expansion valve 6;

[0125] like Figure 4As shown, the evaporator 3 , the electronic expansion valve 6 , the pulse solenoid valve 5 , the condenser 2 and the compressor 1 are connected in series in sequence to form a loop, and the evaporator fan 4 is arranged at the evaporator 3 .

[0126] Optionally, the sensor unit includes an in-box temperature sensor 7, an evaporator outlet temperature sensor 8, and an evaporator outlet pressure sensor 9;

[0127] The evaporator outlet temperature sensor 8 is arranged at the outlet of the evaporator 3; the evaporator outlet pressure sensor 9 is arranged at the outlet of the evaporator 3;

[0128] The control unit includes a fan speed control module 10, an electronic expansion valve opening control module 11, a pulse solenoid valve opening control module 12 and a collection calculation control module 13;

[0129] The acquisition calculation control module 13 is electrically connected to the sensor in the sensor unit, the fan speed control module 10, the electronic expansion valve opening control module 11, and the pulse solenoid valve opening control module 12 respectively;

[0130] The fan speed control module 10 is electrically connected to the evaporator fan 4;

[0131] The electronic expansion valve opening control module 11 is electrically connected to the electronic expansion valve 6;

[0132] The pulse solenoid valve opening control module 12 is electrically connected to the pulse solenoid valve 5 .

[0133] Specifically, the acquisition calculation control module 13 is used to obtain the current temperature of the test box; determine the control deviation of the pulse solenoid valve based on the current temperature and the preset temperature parameters of the test box; determine the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve; determine the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve; determine the opening of the electronic expansion valve based on the opening of the pulse solenoid valve; determine the speed of the evaporator fan based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve; then generate corresponding control instructions based on the calculated opening of the pulse solenoid valve, the opening of the electronic expansion valve and the speed of the evaporator fan, and transmit the corresponding control instructions to the pulse solenoid valve opening control module 12, the electronic expansion valve opening control module 11 and the fan speed control module 10 respectively, so that the pulse solenoid valve opening control module 12, the electronic expansion valve opening control module 11, and the fan speed control module 10 respectively control the pulse solenoid valve 5, the electronic expansion valve 6, and the evaporator fan 4 of the test box to perform corresponding actions, so as to achieve high stability of the test box and linear cooling control with a large cooling rate adaptation range.

[0134] The test box provided in the embodiment of the present invention uses the temperature reduction control method of the test box in the above embodiment, so the test box provided in the embodiment of the present invention also has the beneficial effects described in the above embodiment, which will not be described in detail here.

[0135] In the description of the embodiments of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0136] Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for controlling the temperature of a test chamber, characterized in that: The temperature reduction control method comprises: Get the current temperature of the test chamber; Determining a control deviation of the pulse solenoid valve based on the current temperature and preset temperature parameters of the test chamber, wherein the preset temperature parameters at least include a set starting temperature, a set target temperature, and a target cooling time of the test chamber; Determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve, wherein the gain coefficient is obtained by querying a preset database, and the preset database stores a relationship table between the linear cooling rate of the test box, the control deviation of the pulse solenoid valve, and the gain coefficient; determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve; determining the opening of the electronic expansion valve based on the opening of the pulse solenoid valve; The rotation speed of the evaporator fan is determined based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve to control the test box to cool down.

2. The temperature reduction control method of the test chamber according to claim 1, characterized in that: Determining the control deviation of the pulse solenoid valve based on the current temperature and the preset temperature parameter of the test box includes: Using the formula Determine the control deviation of the pulse solenoid valve, where e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, t≥τ≥0, T is the current temperature, T0 is the set starting temperature, T SV A target temperature is set for the .

3. The temperature reduction control method of the test chamber according to claim 1, characterized in that: Determining the opening increment of the pulse solenoid valve based on the control deviation and gain coefficient of the pulse solenoid valve includes: The opening increment ΔZ (τ) of the pulse solenoid valve is determined based on the following formula: ΔZ(τ)=k·P1·[e1(τ)-e1(τ-1)]+k·I1·e1(τ)+k·D1·[e1(τ)- 2e1(τ-1)+e1(τ-2)]; Among them, k is the gain coefficient, P1 is the proportional coefficient, I1 is the integral coefficient, D1 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e1(τ), e1(τ-1), e1(τ-2) are the control deviations of the pulse solenoid valve at τ, τ-1, τ-2 respectively.

4. The temperature reduction control method of the test chamber according to claim 1, characterized in that: Determining the opening of the pulse solenoid valve based on the opening increment of the pulse solenoid valve includes: The opening of the pulse solenoid valve is determined based on the formula Z(τ)=Z(τ-1)+ΔZ(τ), wherein Z(τ) is the opening of the pulse solenoid valve at time τ, Z(τ-1) is the opening of the pulse solenoid valve at time τ-1, and ΔZ(τ) is the opening increment of the pulse solenoid valve.

5. The temperature reduction control method of the test chamber according to claim 1, characterized in that: Determining the opening degree of the electronic expansion valve based on the opening degree of the pulse solenoid valve includes: determining a control deviation of the electronic expansion valve based on the opening degree of the pulse solenoid valve; determining an opening increment of the electronic expansion valve based on a control deviation of the electronic expansion valve; The opening degree of the electronic expansion valve is determined based on the opening degree increment of the electronic expansion valve.

6. The temperature reduction control method of the test chamber according to claim 5, characterized in that: Determining the control deviation of the electronic expansion valve based on the opening of the pulse solenoid valve includes: Using the formula e2(τ)=MIN[exp(e1(τ)), Y e ]·(Y Z ·sinZ) to determine the control deviation of the electronic expansion valve, wherein e2(τ) is the control deviation of the electronic expansion valve, e1(τ) is the control deviation of the pulse solenoid valve, τ is any time within the target cooling time t, and Y e is the maximum gain coefficient of the opening degree of the electronic expansion valve, Y z is the opening equity coefficient of the pulse solenoid valve, and Z is the opening of the pulse solenoid valve.

7. The temperature reduction control method of the test chamber according to claim 5, characterized in that: Determining the opening increment of the electronic expansion valve based on the control deviation of the electronic expansion valve includes: The opening increment ΔE(τ) of the electronic expansion valve is determined based on the following formula: ΔE(τ)=P2·[e2(τ)-e2(τ-1)]+I2·e2(τ)+D2·[e2(τ)-2e2(τ-1)+ e2(τ-2)]; Among them, P2 is the proportional coefficient, I2 is the integral coefficient, D2 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e2(τ), e2(τ-1), e2(τ-2) are the control deviations of the electronic expansion valve at τ, τ-1, τ-2 respectively.

8. The temperature reduction control method of the test chamber according to claim 5, characterized in that: Determining the opening degree of the electronic expansion valve based on the opening degree increment of the electronic expansion valve includes: The opening of the electronic expansion valve is determined based on the 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 opening increment of the electronic expansion valve.

9. The temperature reduction control method of the test chamber according to claim 1, characterized in that: Determining the rotation speed of the evaporator fan based on the superheat of the evaporator, the opening of the pulse solenoid valve and the opening of the electronic expansion valve includes: When the superheat of the evaporator is less than or equal to the critical superheat, the speed of the evaporator fan is the maximum speed of the fan; When the superheat of the evaporator is greater than the critical superheat, the speed of the evaporator fan is determined by the following method: determining a control deviation of the evaporator fan based on the opening of the pulse solenoid valve and the opening of the electronic expansion valve; determining a speed increment of the evaporator fan based on a control deviation of the evaporator fan; The speed of the evaporator fan is determined based on the speed increment of the evaporator fan.

10. The temperature reduction control method of the test chamber according to claim 9, characterized in that: Determining the control deviation of the evaporator fan based on the opening of the pulse solenoid valve and the opening of the electronic expansion valve includes: Using the formula Determine the control deviation of the evaporator fan, where e3(τ) is the control deviation of the evaporator fan, k0 is the superheat of the evaporator, k obj is the control target value of the evaporator superheat, τ is any time within the target cooling time t, T is the current temperature, T0 is the set starting temperature, T SV is the set target temperature, Z is the opening degree of the pulse solenoid valve, and E is the opening degree of the electronic expansion valve.

11. The temperature reduction control method of the test chamber according to claim 9, characterized in that: Determining the speed increment of the evaporator fan based on the control deviation of the evaporator fan includes: The speed increment ΔH (τ) of the evaporator fan is determined based on the following formula: ΔH(τ)=P3·[e3(τ)-e3(τ-1)]+I3·e3(τ)+D3·[e3(τ)-2e3(τ-1)+ e3(τ-2)]; Among them, P3 is the proportional coefficient, I3 is the integral coefficient, D3 is the differential coefficient, τ, τ-1, τ-2 are all moments within the target cooling time t, e3(τ), e3(τ-1), e3(τ-2) are the control deviations of the evaporator fan at τ, τ-1, τ-2 respectively.

12. The temperature reduction control method of the test chamber according to claim 9, characterized in that: Determining the speed of the evaporator fan based on the speed increment of the evaporator fan includes: The speed of the evaporator fan is determined based on the formula H(τ)=H(τ-1)+ΔH(τ), wherein H(τ) is the speed of the evaporator fan at time τ, H(τ-1) is the speed of the evaporator fan at time τ-1, and ΔH(τ) is the speed increment of the evaporator fan.

13. A test box, characterized in that: The test box includes a box body, a control system and a refrigeration system, and the control system executes the temperature reduction control method of the test box according to any one of claims 1 to 12 above; The control system comprises a display unit, a sensor unit and a control unit, wherein the sensor unit is arranged in the box, the display unit is arranged on the surface of the box, the control unit is arranged in the box or outside the box, and the display unit and the sensor unit are electrically connected to the control unit respectively; The refrigeration system is arranged in the box, and includes a compressor, a condenser, an evaporator, an evaporator fan, a pulse solenoid valve and an electronic expansion valve; The evaporator, the electronic expansion valve, the pulse solenoid valve, the condenser and the compressor are connected in series in sequence to form a loop, and the evaporator fan is arranged at the evaporator.

14. The test box according to claim 13, characterized in that: The sensor unit includes an in-box temperature sensor, an evaporator outlet temperature sensor, and an evaporator outlet pressure sensor; The evaporator outlet temperature sensor is arranged at the outlet of the evaporator; the evaporator outlet pressure sensor is arranged at the outlet of the evaporator; The control unit includes a fan speed control module, an electronic expansion valve opening control module, a pulse solenoid valve opening control module and a collection calculation control module; The acquisition calculation control module is electrically connected to the sensor in the sensor unit, the fan speed control module, the electronic expansion valve opening control module, and the pulse solenoid valve opening control module respectively; The fan speed control module is electrically connected to the evaporator fan; The electronic expansion valve opening control module is electrically connected to the electronic expansion valve; The pulse solenoid valve opening control module is electrically connected to the pulse solenoid valve.

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