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: averagely dividing set parameters of the test box into a set number of sections; calculating a reference increment of each set parameter in each segment; determining target control values of the setting parameters in different segments based on the reference increments and the control gain coefficients of the setting parameters; and regulating and controlling the setting parameters in the corresponding sections based on the target control values of the setting parameters in the different sections so as to control the test box to cool. The technical problems that in the prior art, due to the fact that an environment test box only depends on the maximum refrigerating capacity to conduct model selection of the fixed-frequency compressor, the energy consumption of the fixed-frequency compressor is high, and the capacity is wasted in the initial operation stage are solved, and the technical effect that all set parameters including the rotating speed of the variable-frequency compressor are regulated and controlled in a time-phased and high-precision mode is achieved; the operation reliability of the test box is improved, and the operation energy consumption of the test box is reduced.

Description

Technical Field

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

[0002] With the continuous advancement of life and technology, the demand for product reliability is becoming increasingly higher. In many fields, it is necessary to test the reliability of products or components during the process of cooling from high temperature to low temperature over a certain period of time, and to test changes in material stress and material properties.

[0003] During linear cooling, as the temperature drops, the cooling capacity demand increases, while as the temperature drops, the evaporation temperature also needs to decrease. When the condensing temperature remains constant, the compressor's cooling capacity decreases as the evaporation temperature decreases. Therefore, the compressor's capacity at the beginning and end of linear cooling varies significantly.

[0004] At present, linear cooling mostly uses fixed-frequency compressors, and the compressor selection is usually based on the maximum cooling capacity requirement of the linear cooling process. However, this will result in higher overall compressor energy consumption during the linear cooling process, making the system operation energy consumption higher. Summary of the Invention

[0005] The embodiments of the present invention provide a temperature reduction control method for a test chamber and a test chamber, which solve the technical problems in the prior art of selecting a fixed-frequency compressor for an environmental test chamber based solely on maximum cooling capacity, such as high energy consumption of the fixed-frequency compressor and waste of capacity in the initial stage of operation.

[0006] An embodiment of the present invention provides a temperature reduction control method for a test chamber, the temperature reduction control method comprising:

[0007] Divide the set parameters of the test box into a set number of segments, wherein the set parameters at least include the speed of the variable frequency compressor, the opening of the electronic expansion valve, the speed of the evaporator fan, and the speed of the condenser fan;

[0008] Calculating a reference increment of each set parameter within each of the segments;

[0009] Determining target control values of the setting parameters in different segments based on the reference increments and the control gain coefficients of the setting parameters, wherein the control gain coefficients of the setting parameters are obtained by querying a preset database, wherein the preset database stores the control gain coefficients corresponding to the setting parameters determined based on the influencing factors of the setting parameters in the test chamber;

[0010] Based on the target control values of the set parameters in different segments, the set parameters in the corresponding segments are regulated to control the test box to cool down.

[0011] Furthermore, the method for establishing the preset database includes:

[0012] Determining a linear cooling rate of the test chamber based on preset temperature parameters, wherein the preset temperature parameters include at least a set starting temperature, a set target temperature, and a target cooling time of the test chamber;

[0013] Divide the cooling section into a set number of segments and calculate the starting temperature of each segment;

[0014] Obtaining equipment operating parameters of the test chamber, wherein the equipment operating parameters at least include variable frequency compressor suction pressure, variable frequency compressor exhaust pressure, condensing temperature, condenser liquid supply temperature, evaporation temperature, and evaporator outlet temperature;

[0015] Calculating the state parameters of the test box based on the equipment operating parameters, wherein the state parameters at least include the compression ratio of the variable frequency compressor, the condenser subcooling, and the evaporator superheating;

[0016] The preset database is established by taking the linear cooling rate, the segment starting temperature, the equipment operating parameters and the state parameters as influencing factors of the set parameters.

[0017] Furthermore, establishing the preset database by using the linear cooling rate, the segmented starting temperature, the equipment operating parameters, and the state parameters as influencing factors of the set parameters includes:

[0018] Establishing a first preset database between a first gain coefficient and the linear cooling rate and the segmented starting temperature, and establishing a second preset database between a second gain coefficient and the compression ratio of the variable frequency compressor and the condenser subcooling degree, wherein the first gain coefficient and the second gain coefficient are both control gain coefficients for the speed of the variable frequency compressor;

[0019] Establishing a third preset database between a third gain coefficient and the linear cooling rate and the segmented starting temperature; establishing a fourth preset database between a fourth gain coefficient and the variable frequency compressor speed and the condenser subcooling degree; establishing a fifth preset database between a fifth gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat degree; wherein the third gain coefficient, the fourth gain coefficient, and the fifth gain coefficient are all control gain coefficients for the opening of the electronic expansion valve;

[0020] Establishing a sixth preset database between a sixth gain coefficient and the electronic expansion valve opening and the segmented starting temperature; establishing a seventh preset database between a seventh gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat, wherein the sixth gain coefficient and the seventh gain coefficient are both control gain coefficients for the evaporator fan speed;

[0021] An eighth preset database is established between the eighth gain coefficient and the exhaust pressure of the variable frequency compressor and the subcooling degree of the condenser, and a ninth preset database is established between the ninth gain coefficient and the speed of the variable frequency compressor and the segmented starting temperature, wherein the eighth gain coefficient and the ninth gain coefficient are both control gain coefficients for the speed of the condenser fan.

[0022] Furthermore, calculating the reference increment of each setting parameter in each segment includes:

[0023] Based on the formula Calculate the reference increment of the compressor speed, where Δf is the reference increment of the compressor speed, F max is the maximum speed of the variable frequency compressor, F min is the minimum speed of the variable frequency compressor, M is the number of segments of the variable frequency compressor speed;

[0024] Based on the formula Calculate the reference increment of the compressor speed, where Δe is the reference increment of the electronic expansion valve opening, E max is the maximum opening of the electronic expansion valve, E min is the minimum opening of the electronic expansion valve, and A is the number of segments of the electronic expansion valve opening;

[0025] Based on the formula Calculate the reference increment of the evaporator fan speed, where Δh is the reference increment of the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, and B is the number of segments of the evaporator fan speed;

[0026] Based on the formula Calculate the reference increment of the condenser fan speed, where Δd is the reference increment of the condenser fan speed, D max is the maximum speed of the condenser fan, D min is the minimum speed of the condenser fan, and C is the number of segments of the condenser fan speed.

[0027] Furthermore, determining the target control value of each of the setting parameters in different segments based on each of the reference increments and the control gain coefficient of each of the setting parameters includes:

[0028] Based on the formula F=F min +Δf(w1+w2) to determine the speed of the variable frequency compressor in different segments, wherein 0≤w1+w2≤M, F is the speed of the variable frequency compressor, Δf is the reference increment of the compressor speed, w1 is the first gain coefficient, w2 is the second gain coefficient, and M is the number of segments of the variable frequency compressor speed;

[0029] Based on the formula E=E min +Δe(k1+k2+k3) determines the opening of the electronic expansion valve in different segments, wherein 0≤k1+k2+k3≤A, E is the opening of the electronic expansion valve, Δe is the reference increment of the opening of the electronic expansion valve, k1 is the third gain coefficient, k2 is the fourth gain coefficient, k3 is the fifth gain coefficient, and A is the number of segments of the electronic expansion valve opening;

[0030] Based on the formula H=H min +Δh(r1+r2) determines the evaporator fan speed in different segments, wherein 0≤r1+r2≤B, H is the evaporator fan speed, Δh is the reference increment of the evaporator fan speed, r1 is the sixth gain coefficient, r2 is the seventh gain coefficient, and B is the number of segments of the evaporator fan speed;

[0031] Based on the formula D=D min +Δd(p1+p2) determines the condenser fan speed in different segments, where 0≤p1+p2≤C, D is the condenser fan speed, Δd is the reference increment of the condenser fan speed, p1 is the eighth gain coefficient, p2 is the ninth gain coefficient, and C is the number of segments of the condenser fan speed.

[0032] Furthermore, the cooling section is evenly divided into a set number of segments, and the segment starting temperature of each segment is calculated including:

[0033] Divide the cooling section into n segments evenly, using the formula Calculate the segment starting temperature of each segment;

[0034] Wherein, i=1, 2, ..., n, n is the number of segments in the cooling section, i represents the i-th segment among n segments, T0 is the starting temperature of the segment, V is the linear cooling rate, and t is the target cooling time.

[0035] Furthermore, calculating the state parameter of the test box based on the state parameter includes:

[0036] Comparing the exhaust pressure of the variable frequency compressor with the suction pressure of the variable frequency compressor to obtain the compression ratio of the variable frequency compressor;

[0037] Subtracting the condensing temperature from the condenser liquid supply temperature to obtain the condenser subcooling degree;

[0038] The evaporator superheat is obtained by subtracting the evaporator outlet temperature from the evaporation temperature.

[0039] An embodiment of the present invention further provides a test box, comprising a box body, a control system, and a refrigeration system, wherein the control system executes the temperature reduction control method of the test box described in any of the above embodiments;

[0040] The control system includes 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, and the control unit is arranged in or outside the box, and the display unit and the sensor unit are electrically connected to the control unit respectively;

[0041] The refrigeration system is arranged in the box, and includes a variable frequency compressor, a condenser, a condenser fan, an evaporator, an evaporator fan and an electronic expansion valve;

[0042] The evaporator, the electronic expansion valve, the condenser, and the variable frequency compressor are sequentially connected in series to form a loop. The condenser fan is arranged at the condenser, and the evaporator fan is arranged at the evaporator.

[0043] Furthermore, the sensor unit includes an in-box temperature sensor, an evaporator outlet temperature sensor, a variable frequency compressor suction pressure sensor, a variable frequency compressor discharge pressure sensor, and a condenser supply liquid temperature sensor;

[0044] The temperature sensor in the box is arranged in the box;

[0045] The evaporator outlet temperature sensor is arranged at the outlet of the evaporator;

[0046] The variable frequency compressor suction pressure sensor is arranged at the air inlet of the variable frequency compressor, and the variable frequency compressor exhaust pressure sensor is arranged at the exhaust port of the variable frequency compressor;

[0047] The condenser liquid supply temperature sensor is arranged at the liquid supply port of the condenser.

[0048] Furthermore, the control unit includes an evaporator fan speed control module, a variable frequency compressor speed control module, an electronic expansion valve opening control module, a condenser fan speed control module and an acquisition calculation control module;

[0049] The acquisition calculation control module is electrically connected to the sensor in the sensor unit, the evaporator fan speed control module, the variable frequency compressor speed control module, the electronic expansion valve opening control module, and the condenser fan speed control module respectively;

[0050] The evaporator fan speed control module is electrically connected to the evaporator fan;

[0051] The variable frequency compressor speed control module is electrically connected to the variable frequency compressor;

[0052] The electronic expansion valve opening control module is electrically connected to the electronic expansion valve;

[0053] The condenser fan speed control module is electrically connected to the condenser fan.

[0054] The present invention discloses a cooling control method for a test chamber and the test chamber. The cooling control method includes: dividing the set parameters of the test chamber into a set number of segments; calculating a baseline increment for each set parameter within each segment; determining a target control value for each set parameter within each segment based on each baseline increment and a control gain coefficient for each set parameter; and regulating each set parameter within the corresponding segment based on the target control value for each set parameter within the different segment to control the cooling of the test chamber. The present invention divides the set parameters of the test chamber into segments, determines a control gain coefficient corresponding to each set parameter based on an influencing factor of each set parameter within the test chamber, and then uses the control gain coefficient within each segment to determine the target control value for each set parameter within each segment. This solves the technical problem of high energy consumption and waste of initial capacity of fixed-frequency compressors in environmental test chambers that is caused by selecting fixed-frequency compressors based solely on maximum cooling capacity in the prior art. The method achieves the technical effect of time-dividing and high-precision regulation of each set parameter, including the speed of a variable-frequency compressor, thereby improving the reliability of the test chamber operation and reducing the operating energy consumption of the test chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a structural diagram of a temperature reduction control method for a test chamber provided by an embodiment of the present invention;

[0056] Figure 2 This is a structural diagram of a test box provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0057] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It will be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all structures.

[0058] It should be noted that the terms "first," "second," and so on, in the specification, claims, and drawings of the present invention are used to distinguish different objects, and are not intended to limit a specific order. The following embodiments of the present invention can be implemented independently or in combination with each other, and the present invention does not impose specific limitations on this.

[0059] Figure 1 It is a structural diagram of a temperature reduction control method for a test chamber provided by an embodiment of the present invention.

[0060] like Figure 1 As shown, the temperature reduction control method of the test chamber specifically includes the following steps:

[0061] S101 , evenly dividing the setting parameters of the test box into a set number of segments, wherein the setting parameters at least include the speed of the variable frequency compressor, the opening of the electronic expansion valve, the speed of the evaporator fan, and the speed of the condenser fan.

[0062] Specifically, the traditional fixed-frequency compressor is replaced by a variable-frequency compressor. Through the variable-frequency technology of the compressor, the cooling output is dynamically matched to achieve on-demand cooling, avoiding the problem of high energy consumption caused by the continuous full-load operation of the traditional compressor; due to the large change in cooling capacity during the linear cooling process, the opening of the electronic expansion valve can change the refrigerant flow into the evaporator to ensure that the cooling output matches the system requirements; for the evaporator and condenser, the control of the evaporator fan and the condenser fan is also crucial. When the air volume of the evaporator fan and the condenser fan is too small, it will affect the system operation reliability and cooling capacity. When the air volume is too large, the energy saving is poor. Therefore, the evaporator fan and the condenser fan also need to be regulated to assist in controlling the cooling environment of the test chamber.

[0063] After determining the set parameters as the variable frequency compressor speed, electronic expansion valve opening, evaporator fan speed, and condenser fan speed, each set parameter is averaged and segmented. Subsequently, each segment of the set parameter is adjusted to improve control accuracy. It should be noted that the number of segment settings for each set parameter can be the same or different, and this is not specifically limited here.

[0064] S102, calculating the reference increment of each setting parameter in each segment.

[0065] Specifically, each set parameter has maximum and minimum value restrictions. When the equipment is in operation, its set parameter cannot exceed the maximum value MAX and minimum value MIN that the equipment can achieve. Therefore, in each segment of the set parameter, the difference between the maximum value MAX and the minimum value MIN (MAX-MIN) is evenly divided into each segment, which is the benchmark increment of the set parameter in a segment. For example, if the segment is X, the benchmark increment is (MAX-MIN) / X.

[0066] Optionally, S102 specifically includes:

[0067] Based on the formula Calculate the reference increment of the compressor speed, where △f is the reference increment of the compressor speed, F max is the maximum speed of the variable frequency compressor, F min is the minimum speed of the variable frequency compressor, M is the number of segments of the variable frequency compressor speed;

[0068] Based on the formula Calculate the reference increment of the compressor speed, where △e is the reference increment of the electronic expansion valve opening, E max is the maximum opening of the electronic expansion valve, E min is the minimum opening of the electronic expansion valve, and A is the number of segments of the electronic expansion valve opening;

[0069] Based on the formula Calculate the reference increment of the evaporator fan speed, where △h is the reference increment of the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, and B is the number of segments of the evaporator fan speed;

[0070] Based on the formula Calculate the reference increment of the condenser fan speed, where △d is the reference increment of the condenser fan speed, D max is the maximum speed of the condenser fan, D min is the minimum speed of the condenser fan, and C is the number of segments of the condenser fan speed.

[0071] S103, determining the target control value of each setting parameter in different segments based on each benchmark increment and the control gain coefficient of each setting parameter, wherein the control gain coefficient of each setting parameter is obtained by querying a preset database, and the preset database stores the control gain coefficient corresponding to each setting parameter determined based on the influencing factor of each setting parameter in the test chamber.

[0072] Specifically, when the test chamber is in the refrigeration operation process, different set parameters have different influencing factors. If an influencing factor changes, the corresponding set parameter will also change. Therefore, by conducting experiments in advance, the control gain coefficient of the corresponding set parameter can be determined using the influencing factor, and a corresponding database can be established. After obtaining the current operating parameters of each device in the current test chamber (i.e., the following device operating parameters), the corresponding database is queried based on the obtained current operating parameters to obtain the control gain coefficient of each device parameter. Finally, the benchmark increment and the queried control gain coefficient are used to determine the target control value of the device parameter in the segment corresponding to the current operating parameter.

[0073] Optionally, S103 specifically includes:

[0074] Based on the formula F=F min +Δf(w1+w2) determines the speed of the variable frequency compressor in different segments, where 0≤w1+w2≤M, F is the speed of the variable frequency compressor, Δf is the reference increment of the compressor speed, w1 is the first gain coefficient, w2 is the second gain coefficient, and M is the number of segments of the variable frequency compressor speed;

[0075] Based on the formula E=E min +Δe(k1+k2+k3) determines the electronic expansion valve opening in different segments, where 0≤k1+k2+k3≤A, E is the electronic expansion valve opening, Δe is the reference increment of the electronic expansion valve opening, k1 is the third gain coefficient, k2 is the fourth gain coefficient, k2 is the fifth gain coefficient, and A is the number of segments of the electronic expansion valve opening;

[0076] Based on the formula H=H min +Δh(r1+r2) determines the evaporator fan speed in different segments, where 0≤r1+r2≤B, H is the evaporator fan speed, Δh is the reference increment of the evaporator fan speed, r1 is the sixth gain coefficient, r2 is the seventh gain coefficient, and B is the number of segments of the evaporator fan speed;

[0077] Based on the formula D=D min +Δd(p1+p2) determines the condenser fan speed in different segments, where 0≤p1+p2≤C, D is the condenser fan speed, Δd is the reference increment of the condenser fan speed, p1 is the eighth gain coefficient, p2 is the ninth gain coefficient, and C is the number of segments of the condenser fan speed.

[0078] Specifically, M, A, B, and C are all determined by the control accuracy of the corresponding set parameters and can be set as needed. It should be noted that for the first gain coefficient w1 and the second gain coefficient w2, since the maximum value of the gain coefficient w multiplied by the number of equally divided segments M is the maximum value of the increment, that is, the maximum value of Δf, in order to limit the maximum value of Δf to not exceed the maximum speed F max , it is necessary to limit 0≤w1+w2≤M. Similarly, the limitations on other gain coefficients are similar to those on the gain coefficient w.

[0079] S104 , regulating each set parameter in the corresponding segment based on the target control value of each set parameter in the different segment, so as to control the test box to cool down.

[0080] Specifically, each set parameter is regulated based on the target control value obtained in different segments, so that the regulation accuracy is improved, and the test chamber can stably and reliably achieve a linear temperature reduction process.

[0081] The present invention divides the setting parameters of the test chamber into even segments, determines the control gain coefficient corresponding to each setting parameter based on the influencing factor of each setting parameter in the test chamber, and then uses the control gain coefficient in different segments to determine the target control value of each setting parameter in each segment. This solves the technical problems in the prior art of the environmental test chamber that the fixed-frequency compressor only relies on the maximum cooling capacity to select the fixed-frequency compressor, such as high energy consumption of the fixed-frequency compressor and waste of capacity in the initial stage of operation. It achieves the technical effect of regulating each setting parameter including the speed of the variable-frequency compressor in a time period and with high precision, thereby improving the reliability of the test chamber operation and reducing the operating energy consumption of the test chamber.

[0082] Optionally, the method for establishing the preset database includes:

[0083] S1, determining a linear cooling rate of the test chamber based on preset temperature parameters, 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.

[0084] 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 controlled environment test chamber.

[0085] S2, divides the cooling section into a set number of segments, and calculates the starting temperature of each segment.

[0086] Optionally, step S2 specifically includes:

[0087] Divide the cooling section into n segments evenly, using the formula Calculate the segment starting temperature of each segment; where i = 1, 2, ..., n, n is the number of segments in the cooling section, i represents the i-th segment among n segments, T0 is the segment starting temperature, V is the linear cooling rate, and t is the target cooling time.

[0088] S3, obtaining equipment operating parameters of the test chamber, wherein the equipment operating parameters at least include variable frequency compressor suction pressure, variable frequency compressor exhaust pressure, condensing temperature, condenser liquid supply temperature, evaporation temperature, and evaporator outlet temperature.

[0089] Specifically, a control system is provided in the environmental test chamber, which includes a display unit, a sensor unit and a control unit. The sensor unit includes an in-box temperature sensor, an evaporator outlet temperature sensor, a variable frequency compressor suction pressure sensor, a variable frequency compressor exhaust pressure sensor and a condenser supply liquid temperature sensor, which can obtain the current temperature in the test chamber and the temperature parameters of each device in real time.

[0090] Among them, the variable frequency compressor exhaust pressure sensor is used to obtain the exhaust pressure of the variable frequency compressor, and then the condensing temperature of the test chamber is calculated based on the exhaust pressure; the variable frequency compressor suction pressure sensor is used to obtain the suction pressure of the variable frequency compressor, and then the evaporation temperature of the test chamber is calculated based on the suction pressure. Other equipment temperature parameters are directly obtained by the corresponding sensors.

[0091] S4, calculating the state parameters of the test box based on the equipment operating parameters, wherein the state parameters at least include the compression ratio of the variable frequency compressor, the subcooling degree of the condenser, and the superheating degree of the evaporator.

[0092] Optionally, step S4 specifically includes:

[0093] Compare the exhaust pressure of the variable frequency compressor with the suction pressure of the variable frequency compressor to obtain the compression ratio of the variable frequency compressor; subtract the condensing temperature from the condenser supply temperature to obtain the condenser subcooling; subtract the evaporator outlet temperature from the evaporation temperature to obtain the evaporator superheat.

[0094] Specifically, after obtaining the variable frequency compressor exhaust pressure HP and the variable frequency compressor suction pressure LP, HP and LP are compared to obtain the variable frequency compressor compression ratio PR = HP / LP; after obtaining the condensing temperature T con and condenser supply liquid temperature T 11 Afterwards, T con With T 11 Subtract and get the condenser subcooling SC=T con -T 11 ; After obtaining the evaporator outlet temperature T8 and evaporation temperature T eva After that, T8 and T eva Subtract and get the evaporator superheat SH = T8-Teva .

[0095] S5, establishing a preset database by taking the linear cooling rate, segment starting temperature, equipment operating parameters and state parameters as influencing factors of the set parameters.

[0096] Optionally, step S5 specifically includes:

[0097] S51, establish a first preset database between the first gain coefficient and the linear cooling rate and the segmented starting temperature, and establish a second preset database between the second gain coefficient and the compression ratio of the variable frequency compressor and the condenser subcooling degree, wherein the first gain coefficient and the second gain coefficient are both control gain coefficients of the variable frequency compressor speed.

[0098] For example, see Table 1 and Table 2. Table 1 shows the relationship between the first gain coefficient w1 and the linear cooling rate V and the segment starting temperature (T0). i Table 2 is a second preset database between the second gain coefficient w2 and the compression ratio PR of the variable frequency compressor, the condenser subcooling degree SC, wherein i represents the i-th segment, j represents the linear cooling rate V or the compression ratio PR of the variable frequency compressor number.

[0099] Table 1. First preset database

[0100]

[0101]

[0102] Table 2. Second preset database

[0103] <![CDATA[SC1]]> <![CDATA[SC2]]> … <![CDATA[SC i ]]> <![CDATA[PR1]]> <![CDATA[w 2_11 ]]> <![CDATA[w 2_12 ]]> … <![CDATA[w 2_1j ]]> <![CDATA[PR2]]> <![CDATA[w 2_21 ]]> <![CDATA[w 2_22 ]]> … <![CDATA[w 2_2j ]]> … … … … … <![CDATA[PR j ]]> <![CDATA[w 2_i1 ]]> <![CDATA[w 2_i2 ]]> … <![CDATA[w 2_ij ]]>

[0104] S52, establish a third preset database between the third gain coefficient and the linear cooling rate and the segmented starting temperature, establish a fourth preset database between the fourth gain coefficient and the variable frequency compressor speed and the condenser subcooling degree, establish a fifth preset database between the fifth gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat, wherein the third gain coefficient, the fourth gain coefficient and the fifth gain coefficient are all control gain coefficients of the electronic expansion valve opening.

[0105] For example, see Table 3, Table 4 and Table 5. Table 3 shows the relationship between the third gain coefficient k1 and the linear cooling rate V and the segment starting temperature (T0). iTable 4 is a fourth preset database between the fourth gain coefficient k2 and the variable frequency compressor speed F and the condenser subcooling degree SC; Table 5 is a fifth preset database between the fifth gain coefficient k3 and the variable frequency compressor suction pressure LP and the evaporator superheat SH, wherein i represents the i-th segment, and j represents the number of the linear cooling rate V, the variable frequency compressor speed F, or the variable frequency compressor suction pressure LP.

[0106] Table 3. The third preset database

[0107]

[0108]

[0109] Table 4. The fourth preset database

[0110] <![CDATA[SC1]]> <![CDATA[SC2]]> … <![CDATA[SC i ]]> <![CDATA[F1]]> <![CDATA[k 2_11 ]]> <![CDATA[k 2_12 ]]> … <![CDATA[k 2_1j ]]> <![CDATA[F2]]> <![CDATA[k 2_21 ]]> <![CDATA[k 2_22 ]]> … <![CDATA[k 2_2j ]]> … … … … … <![CDATA[F j ]]> <![CDATA[k 2_i1 ]]> <![CDATA[k 2_i2 ]]> … <![CDATA[k 2_ij ]]>

[0111] Table 5. Fifth preset database

[0112] SH1 SH2 … SHi <![CDATA[LP1]]> <![CDATA[k 3_11 ]]> <![CDATA[k 3_12 ]]> … <![CDATA[k 3_1j ]]> <![CDATA[LP2]]> <![CDATA[k 3_21 ]]> <![CDATA[k 3_22 ]]> … <![CDATA[k 3_2j ]]> … … … … … <![CDATA[LP j ]]> <![CDATA[k 3_i1 ]]> <![CDATA[k 3_i2 ]]> … <![CDATA[k 3_ij ]]>

[0113] S53, establish a sixth preset database between the sixth gain coefficient and the electronic expansion valve opening and the segmented starting temperature, and establish a seventh preset database between the seventh gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat, wherein the sixth gain coefficient and the seventh gain coefficient are both control gain coefficients for the evaporator fan speed.

[0114] For example, see Table 6 and Table 7. Table 6 shows the sixth gain coefficient r1, the electronic expansion valve opening E, and the segment starting temperature (T0). i Table 7 is a seventh preset database between the seventh gain coefficient r2 and the variable frequency compressor suction pressure LP, the evaporator superheat SH, wherein i represents the i-th segment, j represents the electronic expansion valve opening E or the variable frequency compressor suction pressure LP number.

[0115] Table 6. Sixth preset database

[0116] <![CDATA[(T0)1]]> <![CDATA[(T0)2]]> … <![CDATA[(T0) i ]]> <![CDATA[E1]]> <![CDATA[r 1_11 ]]> <![CDATA[r 1_12 ]]> … <![CDATA[r 1_1j ]]> <![CDATA[E2]]> <![CDATA[r 1_21 ]]> <![CDATA[r 1_22 ]]> … <![CDATA[r 1_2j ]]> … … … … … <![CDATA[E j ]]> <![CDATA[r 1_i1 ]]> <![CDATA[r 1_i2 ]]> … <![CDATA[r 1_ij ]]>

[0117] Table 7. Seventh preset database

[0118] <![CDATA[SH1]]> <![CDATA[SH2]]> … <![CDATA[SH i ]]> <![CDATA[LP1]]> <![CDATA[r 2_11 ]]> <![CDATA[r 2_12 ]]> … <![CDATA[r 2_1j ]]> <![CDATA[LP2]]> <![CDATA[r 2_21 ]]> <![CDATA[r 2_22 ]]> … <![CDATA[r 2_2j ]]> … … … … … <![CDATA[LP i ]]> <![CDATA[r 2_i1 ]]> <![CDATA[r 2_i2 ]]> … <![CDATA[r 2_ij ]]>

[0119] S54, establish an eighth preset database between the eighth gain coefficient and the exhaust pressure of the variable frequency compressor and the subcooling degree of the condenser, and establish a ninth preset database between the ninth gain coefficient and the speed of the variable frequency compressor and the segment starting temperature, wherein the eighth gain coefficient and the ninth gain coefficient are both control gain coefficients for the speed of the condenser fan.

[0120] For example, referring to Table 8 and Table 9, Table 8 is the eighth preset database between the eighth gain coefficient p1 and the compressor exhaust pressure HP and the condenser subcooling degree SC; Table 9 is the ninth gain coefficient p2 and the compressor speed F and the segment starting temperature (T0). i The ninth preset database between , wherein i represents the i-th segment, and j represents the number of the compressor exhaust pressure HP or the compressor speed F.

[0121] Table 8. The eighth preset database

[0122]

[0123]

[0124] Table 9. Ninth preset database

[0125] <![CDATA[(T0)1]]> <![CDATA[(T0)2]]> … <![CDATA[(T0) i ]]> <![CDATA[F1]]> <![CDATA[p 2_11 ]]> <![CDATA[p 2_12 ]]> … <![CDATA[p 2_1j <!-- 9 -->]]> <![CDATA[F2]]> <![CDATA[p 2_21 ]]> <![CDATA[p 2_22 ]]> … <![CDATA[p 2_2j ]]> … … … … … <![CDATA[F j ]]> <![CDATA[p 2_i1 ]]> <![CDATA[p 2_i2 ]]> … <![CDATA[p 2_ij ]]>

[0126] In an embodiment of the present invention, by using the temperature reduction control method of the test chamber provided by the embodiment of the present invention, the speed of the variable frequency compressor and the opening of the electronic expansion valve can be accurately calculated, so that the cooling capacity of the variable frequency compressor matches the required cooling capacity, thereby reducing the energy consumption of the system; at the same time, the speed of the evaporator fan and the speed of the condenser fan can also be accurately calculated, which can reduce the energy consumption of the fan while improving the operating reliability of the system.

[0127] Figure 2 This is a structural diagram of a test box provided by an embodiment of the present invention.

[0128] An embodiment of the present invention further provides a test box, comprising a box body, a control system, and a refrigeration system, wherein the control system executes the temperature reduction control method of the test box in any of the above embodiments;

[0129] 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, and the control unit is arranged in the box or outside the box. The display unit and the sensor unit are electrically connected to the control unit respectively.

[0130] The refrigeration system is arranged in the box, and includes a variable frequency compressor 1, a condenser 2, a condenser fan 3, an evaporator 4, an evaporator fan 5 and an electronic expansion valve 6.

[0131] like Figure 2 As shown, the evaporator 4 , the electronic expansion valve 6 , the condenser 2 and the variable frequency compressor 1 are connected in series to form a loop, the condenser fan 3 is arranged at the condenser 2 , and the evaporator fan 5 is arranged at the evaporator 4 .

[0132] Optionally, the sensor unit includes an in-box temperature sensor 7 , an evaporator outlet temperature sensor 8 , a variable frequency compressor suction pressure sensor 9 , a variable frequency compressor discharge pressure sensor 10 , and a condenser liquid supply temperature sensor 11 .

[0133] like Figure 2 As shown, the box temperature sensor 7 is arranged inside the box;

[0134] The evaporator outlet temperature sensor 8 is arranged at the outlet of the evaporator 4;

[0135] The variable frequency compressor suction pressure sensor 9 is arranged at the air inlet of the variable frequency compressor 1, and the variable frequency compressor exhaust pressure sensor 10 is arranged at the exhaust port of the variable frequency compressor 1;

[0136] The condenser liquid supply temperature sensor 11 is arranged at the liquid supply port of the condenser 2 .

[0137] Optionally, the control unit includes an evaporator fan speed control module 12, a variable frequency compressor speed control module 13, an electronic expansion valve opening control module 14, a condenser fan speed control module 15 and an acquisition calculation control module 16;

[0138] The acquisition calculation control module 16 is electrically connected to the sensor in the sensor unit, the evaporator fan speed control module 12, the variable frequency compressor speed control module 13, the electronic expansion valve opening control module 14, and the condenser fan speed control module 15;

[0139] The evaporator fan speed control module 12 is electrically connected to the evaporator fan 5;

[0140] The variable frequency compressor speed control module 13 is electrically connected to the variable frequency compressor 1;

[0141] The electronic expansion valve opening control module 14 is electrically connected to the electronic expansion valve 6;

[0142] The condenser fan speed control module 15 is electrically connected to the condenser fan 3 .

[0143] Specifically, the acquisition and calculation control module 16 is used to divide the set parameters of the test box into a set number of segments on average, calculate the baseline increment of each set parameter in each segment, determine the target control value of each set parameter in different segments based on each baseline increment and the control gain coefficient of each set parameter, generate corresponding control instructions based on the target control value of each set parameter in different segments, and transmit the corresponding control instructions to the evaporator fan speed control module 12, the variable frequency compressor speed control module 13, the electronic expansion valve opening control module 14 and the condenser fan speed control module 15 respectively, so that the evaporator fan speed control module 12, the variable frequency compressor speed control module 13, the electronic expansion valve opening control module 14 and the condenser fan speed control module 15 respectively control the evaporator fan 5, the variable frequency compressor 1, the electronic expansion valve 6 and the condenser stage 3 of the test box to perform corresponding actions, thereby realizing high reliability and low operating energy consumption linear cooling control of the test box.

[0144] 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. Therefore, 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 again here.

[0145] In the description of the embodiments of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0146] Finally, it should be noted that the above are only preferred embodiments of the present invention and the technical principles employed. 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 detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A test chamber temperature control method, characterized in that: The temperature reduction control method comprises: Divide the set parameters of the test box into a set number of segments, wherein the set parameters at least include the speed of the variable frequency compressor, the opening of the electronic expansion valve, the speed of the evaporator fan, and the speed of the condenser fan; Calculating a reference increment of each set parameter within each of the segments; Determining target control values of the setting parameters in different segments based on the reference increments and the control gain coefficients of the setting parameters, wherein the control gain coefficients of the setting parameters are obtained by querying a preset database, wherein the preset database stores the control gain coefficients corresponding to the setting parameters determined based on the influencing factors of the setting parameters in the test chamber; Based on the target control values of the set parameters in different segments, the set parameters in the corresponding segments are regulated to control the test box to cool down.

2. The test chamber temperature control method according to claim 1, characterized in that: The method for establishing the preset database includes: Determining a linear cooling rate of the test chamber based on preset temperature parameters, wherein the preset temperature parameters include at least a set starting temperature, a set target temperature, and a target cooling time of the test chamber; Divide the cooling section into a set number of segments and calculate the starting temperature of each segment; Obtaining equipment operating parameters of the test chamber, wherein the equipment operating parameters at least include variable frequency compressor suction pressure, variable frequency compressor exhaust pressure, condensing temperature, condenser liquid supply temperature, evaporation temperature, and evaporator outlet temperature; Calculating the state parameters of the test box based on the equipment operating parameters, wherein the state parameters at least include the compression ratio of the variable frequency compressor, the condenser subcooling, and the evaporator superheating; The preset database is established by taking the linear cooling rate, the segment starting temperature, the equipment operating parameters and the state parameters as influencing factors of the set parameters.

3. The test chamber temperature control method according to claim 2, characterized in that: Establishing the preset database by using the linear cooling rate, the segment starting temperature, the equipment operating parameters, and the state parameters as influencing factors of the set parameters includes: Establishing a first preset database between a first gain coefficient and the linear cooling rate and the segmented starting temperature, and establishing a second preset database between a second gain coefficient and the compression ratio of the variable frequency compressor and the condenser subcooling degree, wherein the first gain coefficient and the second gain coefficient are both control gain coefficients for the speed of the variable frequency compressor; Establishing a third preset database between a third gain coefficient and the linear cooling rate and the segmented starting temperature; establishing a fourth preset database between a fourth gain coefficient and the variable frequency compressor speed and the condenser subcooling degree; establishing a fifth preset database between a fifth gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat degree; wherein the third gain coefficient, the fourth gain coefficient, and the fifth gain coefficient are all control gain coefficients for the opening of the electronic expansion valve; Establishing a sixth preset database between a sixth gain coefficient and the electronic expansion valve opening and the segmented starting temperature; establishing a seventh preset database between a seventh gain coefficient and the variable frequency compressor suction pressure and the evaporator superheat, wherein the sixth gain coefficient and the seventh gain coefficient are both control gain coefficients for the evaporator fan speed; An eighth preset database is established between the eighth gain coefficient and the exhaust pressure of the variable frequency compressor and the subcooling degree of the condenser, and a ninth preset database is established between the ninth gain coefficient and the speed of the variable frequency compressor and the segmented starting temperature, wherein the eighth gain coefficient and the ninth gain coefficient are both control gain coefficients for the speed of the condenser fan.

4. The test chamber temperature control method according to claim 1, characterized in that: Calculating the reference increment of each setting parameter in each segment includes: Based on the formula Calculate the reference increment of the compressor speed, where Δf is the reference increment of the compressor speed, F max is the maximum speed of the variable frequency compressor, F min is the minimum speed of the variable frequency compressor, M is the number of segments of the variable frequency compressor speed; Based on the formula Calculate the reference increment of the compressor speed, where Δe is the reference increment of the electronic expansion valve opening, E max is the maximum opening of the electronic expansion valve, E min is the minimum opening of the electronic expansion valve, and A is the number of segments of the electronic expansion valve opening; Based on the formula Calculate the reference increment of the evaporator fan speed, where Δh is the reference increment of the evaporator fan speed, H max is the maximum speed of the evaporator fan, H min is the minimum speed of the evaporator fan, and B is the number of segments of the evaporator fan speed; Based on the formula Calculate the reference increment of the condenser fan speed, where Δd is the reference increment of the condenser fan speed, D max is the maximum speed of the condenser fan, D min is the minimum speed of the condenser fan, and C is the number of segments of the condenser fan speed.

5. The test chamber temperature control method according to claim 3, characterized in that: Determining the target control value of each setting parameter in different segments based on each reference increment and the control gain coefficient of each setting parameter includes: Based on the formula F=F min +Δf(w1+w2) to determine the speed of the variable frequency compressor in different segments, wherein 0≤w1+w2≤M, F is the speed of the variable frequency compressor, Δf is the reference increment of the compressor speed, w1 is the first gain coefficient, w2 is the second gain coefficient, and M is the number of segments of the variable frequency compressor speed; Based on the formula E=E min +Δe(k1+k2+k3) determines the opening of the electronic expansion valve in different segments, wherein 0≤k1+k2+k3≤A, E is the opening of the electronic expansion valve, Δe is the reference increment of the opening of the electronic expansion valve, k1 is the third gain coefficient, k2 is the fourth gain coefficient, k3 is the fifth gain coefficient, and A is the number of segments of the electronic expansion valve opening; Based on the formula H=H min +Δh(r1+r2) determines the evaporator fan speed in different segments, wherein 0≤r1+r2≤B, H is the evaporator fan speed, Δh is the reference increment of the evaporator fan speed, r1 is the sixth gain coefficient, r2 is the seventh gain coefficient, and B is the number of segments of the evaporator fan speed; Based on the formula D=D min +Δd(p1+p2) determines the condenser fan speed in different segments, where 0≤p1+p2≤C, D is the condenser fan speed, Δd is the reference increment of the condenser fan speed, p1 is the eighth gain coefficient, p2 is the ninth gain coefficient, and C is the number of segments of the condenser fan speed.

6. The test chamber temperature control method according to claim 2, characterized in that: Divide the cooling section into a set number of segments and calculate the starting temperature of each segment including: Divide the cooling section into n segments evenly, using the formula Calculate the segment starting temperature of each segment; Wherein, i=1, 2, ..., n, n is the number of segments in the cooling section, i represents the i-th segment among n segments, T0 is the starting temperature of the segment, V is the linear cooling rate, and t is the target cooling time.

7. The test chamber temperature control method according to claim 2, characterized in that: Calculating the state parameter of the test box based on the state parameter includes: Comparing the exhaust pressure of the variable frequency compressor with the suction pressure of the variable frequency compressor to obtain the compression ratio of the variable frequency compressor; Subtracting the condensing temperature from the condenser liquid supply temperature to obtain the condenser subcooling degree; The evaporator superheat is obtained by subtracting the evaporator outlet temperature from the evaporation temperature.

8. A test box, characterized in that: The test chamber includes a chamber body, a control system, and a refrigeration system, wherein the control system executes the temperature reduction control method of the test chamber according to any one of claims 1 to 7; The control system includes 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, and the control unit is arranged in 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 variable frequency compressor, a condenser, a condenser fan, an evaporator, an evaporator fan and an electronic expansion valve; The evaporator, the electronic expansion valve, the condenser, and the variable frequency compressor are sequentially connected in series to form a loop. The condenser fan is arranged at the condenser, and the evaporator fan is arranged at the evaporator.

9. The test box according to claim 8, characterized in that The sensor unit includes an in-box temperature sensor, an evaporator outlet temperature sensor, a variable frequency compressor suction pressure sensor, a variable frequency compressor exhaust pressure sensor, and a condenser liquid supply temperature sensor; The temperature sensor in the box is arranged in the box; The evaporator outlet temperature sensor is arranged at the outlet of the evaporator; The variable frequency compressor suction pressure sensor is arranged at the air inlet of the variable frequency compressor, and the variable frequency compressor exhaust pressure sensor is arranged at the exhaust port of the variable frequency compressor; The condenser liquid supply temperature sensor is arranged at the liquid supply port of the condenser.

10. The test box according to claim 8, characterized in that The control unit includes an evaporator fan speed control module, a variable frequency compressor speed control module, an electronic expansion valve opening control module, a condenser fan speed control module and an acquisition calculation control module; The acquisition calculation control module is electrically connected to the sensor in the sensor unit, the evaporator fan speed control module, the variable frequency compressor speed control module, the electronic expansion valve opening control module, and the condenser fan speed control module respectively; The evaporator fan speed control module is electrically connected to the evaporator fan; The variable frequency compressor speed control module is electrically connected to the variable frequency compressor; The electronic expansion valve opening control module is electrically connected to the electronic expansion valve; The condenser fan speed control module is electrically connected to the condenser fan.

Images