CN114489177B - Temperature control method - Google Patents
Temperature control method Download PDFInfo
- Publication number
- CN114489177B CN114489177B CN202111681784.5A CN202111681784A CN114489177B CN 114489177 B CN114489177 B CN 114489177B CN 202111681784 A CN202111681784 A CN 202111681784A CN 114489177 B CN114489177 B CN 114489177B
- Authority
- CN
- China
- Prior art keywords
- temperature
- control
- segment
- adjustment
- pulse width
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Control Of Temperature (AREA)
Abstract
The invention discloses a temperature control method, and relates to the technical field of temperature adjustment. Firstly, calculating the duty ratio disconnection time length of each sectional control according to a pulse width modulation output value, an adjustment period and an opening threshold value of each sectional control; and then in one adjusting period, after the switching-off time of the duty ratio, starting a sectional adjusting control corresponding to the switching-off time of the duty ratio so as to realize sectional temperature adjustment of the box body. The temperature control method provided by the invention can realize the sectional regulation and control of the temperature regulating device by executing the sectional regulation and control parts with different duty ratios, improves the temperature stability under the slow temperature change state, avoids the output oscillation of PID, reduces the temperature fluctuation, improves the temperature uniformity, and improves the stability and the accuracy of executing the PID output under the fast temperature change state.
Description
Technical Field
The invention relates to the technical field of temperature adjustment, in particular to a temperature control method.
Background
At present, high temperature, low temperature and temperature rise and fall rates are generally simulated in a high and low temperature environment test box. In order to meet the controllability of any temperature point of an environmental test box in a large-range temperature interval, a high-power temperature regulating device is generally adopted for heating or refrigerating, but in this way, the temperature stability is extremely difficult in a slow temperature change state, and the temperature stability is influenced by the minimum response time of electronic components, in the closed loop control of a PID (proportion-integral-derivative controller), when the output of the PID is infinitely close to 0%, a solid relay for driving heating and an electromagnetic valve for driving refrigerating cannot be connected, so that the oscillation (switching between heating and refrigerating) of the PID output is caused, the temperature fluctuation is large, and the temperature uniformity is poor. In addition, the existing test box has the defects of overlarge output power, higher energy consumption and poor stability and accuracy of executing PID output when executing large PID output under a fast temperature change state.
In view of this, it is important to design a uniform, stable, accurate and reliable temperature control method, especially in environmental test chambers.
Disclosure of Invention
The invention aims to provide a temperature control method which can realize sectional regulation and control of temperature, improve the stability of temperature in a slow temperature change state, avoid the output oscillation of PID, reduce temperature fluctuation, improve temperature uniformity and improve the stability and accuracy of executing PID output in a fast temperature change state.
The invention is realized by adopting the following technical scheme.
The temperature control method is applied to an environment test box, the environment test box comprises a box body, a controller, a temperature adjusting device and at least two sectional adjusting pieces, the temperature adjusting device is connected with the box body through the at least two sectional adjusting pieces so as to adjust the temperature of the box body, and the controller is electrically connected with the at least two sectional adjusting pieces at the same time, and the temperature control method comprises the following steps: calculating the duty ratio disconnection time length of each sectional control according to the pulse width modulation output value, the adjustment period and the opening threshold value of each sectional control; and in one regulation period, after the switching-off time of the duty ratio, starting a sectional regulation control corresponding to the switching-off time of the duty ratio so as to realize sectional temperature regulation of the box body.
Optionally, before the step of calculating the duty cycle off duration of each segment modulation control according to the pulse width modulation output value, the adjustment period and the opening threshold value of each segment modulation control, the temperature control method further includes: calculating a pulse width modulation output value according to the preset temperature and the actual temperature in the box body; setting an adjusting period according to the hardware life and the minimum response time of the temperature adjusting device and the calculated frequency of the controller; and calculating the opening threshold value of each sectional control piece according to the total power of the temperature regulating device and the sub power of each sectional control piece.
Optionally, the step of calculating the pulse width modulation output value according to the preset temperature and the actual temperature in the box body includes: the method comprises the steps that a register is used for inputting preset temperature into a controller, and a temperature sensor is used for collecting the actual temperature in a box body and inputting the actual temperature into the controller; setting a proportional parameter, an integral parameter and a differential parameter of the controller, and setting a pulse width modulation output value output by the controller to be bipolar; and calculating to obtain a pulse width modulation output value.
Optionally, the controller includes PID control module and a plurality of PLC control module, and register and temperature sensor all are connected with PID control module electricity, and PID control module is used for calculating out pulse width modulation output value, and PID control module is connected with a plurality of PLC control module electricity simultaneously, and a plurality of PLC control module are connected with a plurality of segmentation accent controlling parts electricity in one-to-one correspondence, and every PLC control module is used for controlling a segmentation accent controlling part and adjusts the temperature.
Optionally, in the step of calculating the opening threshold value of each segment tuning element according to the total power of the temperature adjusting device and the sub-power of each segment tuning element, a calculation formula of the opening threshold value of the segment tuning element is as follows:
S M1 ＝0；
wherein a is a ratio parameter, a ranges from 0.8 to 1.2, S M1 For the opening threshold value of the first segment control piece, S Mn Is the opening threshold value of the nth sectional temperature regulating control, QW is the total power of the temperature regulating device, and QW 1 Adjusting the sub-power of the control for the first segment, QW n-1 The sub-power of the control is adjusted for the n-1 th segment.
Optionally, a=1, and the calculation formula of the opening threshold value of the segment tuning control is:
S M1 ＝0；
optionally, in the step of calculating the duty cycle disconnection time length of each segment tuning control according to the pulse width modulation output value, the adjustment period and the opening threshold value of each segment tuning control, a calculation formula of the duty cycle disconnection time length of the segment tuning control is as follows:
if M is less than or equal to S Mn TS is then Mn ＝T M ；
If M > S Mn Then
Wherein M is a pulse width modulation output value, S Mn Opening threshold value of nth segment control part, TS Mn The duty ratio of the nth segment control is cut-off time length, T M To adjust the period.
Optionally, the number of the segment adjustment controls is three, the duty cycle disconnection time length of the first segment adjustment control is smaller than the duty cycle disconnection time length of the second segment adjustment control, and the duty cycle disconnection time length of the second segment adjustment control is smaller than the duty cycle disconnection time length of the third segment adjustment control; in one adjusting period, after the duty ratio off-time, starting a segment adjusting control corresponding to the duty ratio off-time to realize segment temperature adjustment of the box body, wherein the step of adjusting the temperature of the box body comprises the following steps: in one adjusting period, after the duty ratio of the first sectional adjusting part is cut off, starting the first sectional adjusting part, and adjusting the temperature of the box body by the first sectional adjusting part at the moment; after the duty ratio of the second sectional control part is cut off, the second sectional control part is started, and at the moment, the first sectional control part and the second sectional control part regulate the temperature of the box body at the same time; after the switching-off time of the duty ratio of the third sectional control part, the third sectional control part is started, and at the moment, the first sectional control part, the second sectional control part and the third sectional control part are used for simultaneously regulating the temperature of the box body.
Optionally, the temperature adjusting device comprises an electric heater and a compression refrigerator, the sectional adjusting and controlling piece comprises a relay and a refrigeration valve, the electric heater is connected with the box body through the relay to heat the box body, the compression refrigerator is connected with the box body through the refrigeration valve to refrigerate the box body, and the pulse width modulation output value comprises a pulse width modulation heating output value and a pulse width modulation refrigeration output value; when M is more than 0, H=M and L=0, the electric heater and the relay are started, and the compression refrigerator and the refrigeration valve are not started; when m=0, h=l=m=0, and at this time, the electric heater, the relay, the compression refrigerator, and the refrigeration valve are not activated; when M is smaller than 0, L= -M and H=0, at the moment, the electric heater and the relay are not started, and the compression refrigerator and the refrigeration valve are started; wherein M is a pulse width modulation output value, M is more than or equal to-100% and less than or equal to 100%, H is a pulse width modulation heating output value, and L is a pulse width modulation refrigeration output value.
Optionally, after the duty cycle off-time is passed in one adjustment period, starting a segment adjustment control corresponding to the duty cycle off-time to realize segment adjustment of the temperature of the box, and the temperature control method further comprises: and calculating the duty ratio disconnection time length of each sectional control piece according to the pulse width modulation output value, the adjustment period and the opening threshold value of each sectional control piece, and entering the next adjustment period.
The temperature control method provided by the invention has the following beneficial effects:
according to the temperature control method provided by the invention, firstly, the duty ratio disconnection time length of each sectional control piece is calculated according to the pulse width modulation output value, the adjustment period and the opening threshold value of each sectional control piece; and then in one adjusting period, after the switching-off time of the duty ratio, starting a sectional adjusting control corresponding to the switching-off time of the duty ratio so as to realize sectional temperature adjustment of the box body. Compared with the prior art, the temperature control method provided by the invention has the advantages that the step of sectionally regulating the temperature of the box body by the temperature regulating device is realized by starting the sectionally regulating control corresponding to the duty ratio off-time after the sectionally duty ratio off-time is calculated in one regulating period, so that the sectionally regulating and controlling of the temperature regulating device can be realized by executing the sectionally regulating and controlling parts with different duty ratios, the stability of the temperature in a slow temperature state is improved, the output oscillation of PID is avoided, the temperature fluctuation is reduced, the temperature uniformity is improved, and the stability and the accuracy of executing PID output in a fast temperature state are improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a block diagram of an environmental test chamber to which the temperature control method of the present invention is applied;
FIG. 2 is a block diagram of a controller in an environmental test chamber to which the temperature control method of the present invention is applied, connected to a segment control member;
FIG. 3 is a block diagram illustrating steps of a temperature control method according to the present invention;
FIG. 4 is a graph showing the adjustment of the PID control module output in the temperature control method according to embodiment 1 of the present invention;
fig. 5 is an amplification chart of the output power of the relay in the temperature control method according to embodiment 2 of the present invention;
FIG. 6 is a graph showing the adjustment of the PID control module output in the temperature control method according to comparative example 1 of the present invention;
fig. 7 is an amplification graph of the output power of the relay in the temperature control method provided in comparative example 2 of the present invention.
Icon: 100-environmental test chamber; 110-a box body; 120-registers; 130-a temperature sensor; 140-a controller; 141-PID control module; 142-a PLC control module; 150-a temperature regulating device; 151-an electric heater; 152-compression refrigerator; 160-segmenting the control; 161-relay; 162-refrigeration valve.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "inner", "outer", "upper", "lower", "horizontal", etc., are directions or positional relationships based on those shown in the drawings, or those that are conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "connected," "mounted," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Some embodiments of the present invention are described in detail below with reference to the accompanying drawings. Features of the embodiments described below may be combined with each other without conflict.
Referring to fig. 1, 2 and 3, an embodiment of the present invention provides a temperature control method for controlling the temperature of an environmental test chamber 100. The method can realize sectional regulation and control of temperature, improve the stability of the temperature in a slow temperature change state, avoid the output oscillation of PID, reduce temperature fluctuation, improve temperature uniformity and improve the stability and accuracy of executing PID output in a fast temperature change state.
It should be noted that, the temperature control method is applied to the environmental test chamber 100, and the environmental test chamber 100 includes a chamber body 110, a register 120, a temperature sensor 130, a controller 140, a temperature adjustment device 150, and at least two segmented adjustment members 160. The temperature adjusting device 150 is connected with the box 110 through at least two sectional adjusting pieces 160 to adjust the temperature of the box 110, and the temperature adjusting device 150 is used for outputting heating quantity or refrigerating capacity and outputting the heating quantity or refrigerating capacity into the box 110 through the sectional adjusting pieces 160 to realize the heating or refrigerating function of the box 110. The controller 140 is electrically connected to at least two segment tuning elements 160 at the same time, and the controller 140 is configured to perform a temperature control method, so that the segment tuning elements 160 are started or suspended, thereby realizing segment tuning of temperature, improving stability of temperature in a slow temperature state, avoiding output oscillation of PID, reducing temperature fluctuation, improving temperature uniformity, and improving stability and accuracy of performing PID output in a fast temperature state.
Further, the register 120 and the temperature sensor 130 are both connected to the controller 140, the register 120 is used for inputting a preset temperature to the controller 140, and the temperature sensor 130 is used for collecting an actual temperature in the tank 110 and inputting it to the controller 140.
In this embodiment, the controller 140 includes a PID control module 141 and a plurality of PLC control modules 142. The register 120 and the temperature sensor 130 are electrically connected with the PID control module 141, so that the preset temperature and the actual temperature are input into the PID control module 141, and the PID control module 141 is used for calculating a pulse width modulation output value. The PID control module 141 is electrically connected to the plurality of PLC control modules 142 at the same time, the plurality of PLC control modules 142 are electrically connected to the plurality of segment tuning control members 160 in a one-to-one correspondence manner, each PLC control module 142 is configured to control one segment tuning control member 160 to perform temperature adjustment, and the PID control module 141 can control different segment tuning control members 160 to start or pause through the PLC control modules 142 in different time periods.
Notably, the thermostat 150 includes an electric heater 151 and a compression refrigerator 152, and the segmented control 160 includes a relay 161 and a refrigeration valve 162. The electric heater 151 is connected to the case 110 through a relay 161 to heat the case 110; after the electric heater 151 is started, the relay 161 needs to be controlled to be started, so that the heating capacity of the electric heater 151 can be conveyed into the box 110, and the box 110 is heated. The compression refrigerator 152 is connected to the case 110 through a refrigeration valve 162 to refrigerate the case 110; after the compression refrigerator 152 is started, the refrigeration valve 162 needs to be controlled to be started, so that the refrigerating capacity of the compression refrigerator 152 can be conveyed into the box 110, and the box 110 is cooled.
In this embodiment, the sectional control 160 includes three relays 161 and three refrigeration valves 162, where the three relays 161 can divide the total power of the electric heater 151 into three parts to realize sectional heating of the tank 110, and the three refrigeration valves 162 can divide the total power of the compression refrigerator 152 into three parts to realize sectional refrigeration of the tank 110. Specifically, the number of PLC control modules 142 is six, and each PLC control module 142 is electrically connected to one relay 161 or one refrigeration valve 162, so as to control each relay 161 or each refrigeration valve 162, respectively, thereby improving stability and accuracy of temperature control. However, the present invention is not limited thereto, and in other embodiments, the sectionalizing control 160 may include two relays 161 and two refrigeration valves 162, and may also include four relays 161 and four refrigeration valves 162, and the number of relays 161 and refrigeration valves 162 in the sectionalizing control 160 is not particularly limited.
The temperature control method comprises the following steps:
step S110: the pwm output value is calculated according to the preset temperature and the actual temperature in the case 110.
Specifically, step S110 includes three steps, namely:
step S111: the preset temperature is input to the controller 140 by the register 120, and the actual temperature in the case 110 is acquired by the temperature sensor 130 and input to the controller 140.
It should be noted that, in step S111, the PID control module 141 is invoked, and the register 120 and the temperature sensor 130 are connected to the input terminal of the PID control module 141, so as to send the preset temperature data and the actual temperature data to the PID control module 141.
Step S112: the proportional, integral and derivative parameters of the controller 140 are set and the pwm output value of the controller 140 is set to bipolar.
It should be noted that, in step S112, the preset temperature and the actual temperature are displayed on the HMI interface of the controller 140, and the setting value display control is set to be readable and writable (the HMI interface can change the setting value), and the history data storage and the history data curve drawing are configured on the HMI interface.
Specifically, the pulse width modulation output values are bipolar, the pulse width modulation output values comprise pulse width modulation heating output values and pulse width modulation refrigerating output values, the range of the pulse width modulation output values is-100% to 100%, the range of the pulse width modulation refrigerating output values is-100% to 0, and the range of the pulse width modulation heating output values is 0 to 100%. For ease of understanding, M is expressed as a pulse width modulation output value, -100% M100%; h is expressed as a pulse width modulation heating output value, and H is more than or equal to 0 and less than or equal to 100 percent; l is a pulse width modulation refrigeration output value which is more than or equal to-100% and less than or equal to 0.
Step S113: and calculating to obtain a pulse width modulation output value.
In step S113, the PID control module 141 calculates and outputs a pulse width modulation output value. When M >0, h=m, l=0, at which time the electric heater 151 and the relay 161 are activated, the compression refrigerator 152 and the refrigeration valve 162 are not activated, and the electric heater 151 heats the case 110 through the relay 161 to raise the temperature inside the case 110; when m=0, h=l=m=0, and at this time, the electric heater 151, the relay 161, the compression refrigerator 152, and the refrigeration valve 162 are not activated, keeping the temperature inside the tank 110 unchanged; when M <0, l= -M, h=0, at which time the electric heater 151 and the relay 161 are not activated, the compression refrigerator 152 and the refrigeration valve 162 are activated, and the compression refrigerator 152 cools the case 110 through the refrigeration valve 162 to reduce the temperature inside the case 110.
Step S120: the adjustment period is set according to the hardware life and minimum response time of the thermostat 150 and the calculated frequency of the controller 140.
In step S120, the adjustment period is a duration of one duty cycle, and the specific duration of the adjustment period is not particularly limited, and a technician may set the adjustment period according to the hardware lifetime and the minimum response duration of the temperature adjustment device and the calculation frequency of the controller. In the present embodiment, the adjustment period of the relay 161 ranges from 2 to 3 seconds, and the adjustment period of the refrigeration valve 162 ranges from 10 to 14 seconds.
Step S130: the opening threshold value of each segment tuning control 160 is calculated according to the total power of the temperature adjusting device 150 and the sub-power of each segment tuning control 160.
In step S130, the calculation formula of the opening threshold of the segment adjustment control 160 is as follows:
S M1 ＝0；
wherein a is a ratio parameter, a ranges from 0.8 to 1.2, S M1 For the opening threshold of the first segment tuning control 160, S Mn For the opening threshold of the nth segment tuning control 160, QW is the total power of the tuning device 150, QW 1 For the first segment, the sub-power of control 160, QW n-1 The sub-power of control 160 is adjusted for the n-1 th segment.
In this embodiment, a=1, n=3, and the calculation formula of the opening threshold of the piecewise adjustment control 160 is:
S M1 ＝0；
however, in other embodiments, a may be equal to 0.8 or 1.2, and if the range is exceeded, the opening threshold of the segment control 160 and the power matching of the temperature control device 150 connected thereto are too low, which may reduce the accuracy of PID execution.
Meanwhile, the opening threshold value of each sectional control piece 160 is calculated through the total power of the temperature adjusting device 150 and the sub power of each sectional control piece 160 (the relay 161 or the refrigeration valve 162), and the calculation according to the calculation formula is beneficial to enabling the temperature adjustment to be smoother, and the energy consumption can be reduced.
Step S140: and calculating the duty ratio disconnection time length of each segment regulating control 160 according to the pulse width modulation output value, the regulating period and the opening threshold value of each segment regulating control 160.
In step S140, the calculation formula of the duty cycle off duration of the segment adjustment control 160 is as follows:
if M is less than or equal to S Mn TS is then Mn ＝T M ；
If M > S Mn Then
Wherein M is a pulse width modulation output value, S Mn For the opening threshold of the nth segment control 160, TS Mn For the duty cycle off-time length, T, of the nth segment control 160 M To adjust the period.
In this embodiment, n=3, when the pulse width modulation output value is less than or equal to the opening threshold of the sectionalized modulating control 160, the pulse width modulation output value does not reach or just reaches the opening threshold of the sectionalized modulating control 160, and the on-duty turn-off duration of the sectionalized modulating control 160 is equal to the adjustment period, that is, the sectionalized modulating control 160 is always in the turn-off and pause state in the whole adjustment period, the sectionalized modulating control 160 does not apply work to the tank 110, that is, the relay 161 and the refrigeration valve 162 are not started in the whole adjustment period, and the tank 110 is not heated or refrigerated.
When the pulse width modulation output value is greater than the opening threshold value of the segment control 160, the pulse width modulation output value exceeds the opening threshold value of the segment control 160, and the pulse width modulation output value, the adjustment period and the opening threshold value of the segment control 160 are calculated by using the formula to obtain the duty ratio disconnection time length of the segment control 160. In one adjustment period, after the duty cycle off period is reached, the sectionalized adjustment control 160 is started until the adjustment period is finished, and in the process of starting the sectionalized adjustment control 160, the sectionalized adjustment control 160 can apply work to the box 110, that is, in the process of starting the sectionalized adjustment control 160, the relay 161 or the refrigeration valve 162 is started to heat or refrigerate the box 110.
Specifically, during heating, M >0, h=m; when the pulse width modulation heating output value is smaller than or equal to the opening threshold value of the relay 161, the pulse width modulation heating output value does not reach or just reaches the opening threshold value of the relay 161, and at the moment, the switching-off duration of the duty ratio of the relay 161 is equal to the regulating period, namely, the relay 161 is always in a switching-off and suspending state in the whole regulating period; when the pulse width modulation heating output value is greater than the opening threshold value of the relay 161, the duty cycle off time of the relay 161 is calculated by using the formula at the moment, and in one adjustment period, after the duty cycle off time is reached, the relay 161 is started until the adjustment period is ended.
Accordingly, during refrigeration, M <0, l= -M; when the pulse width modulation refrigeration output value is smaller than or equal to the opening threshold value of the refrigeration valve 162, the pulse width modulation refrigeration output value does not reach or just reaches the opening threshold value of the refrigeration valve 162, and at this time, the off-time length of the duty cycle of the refrigeration valve 162 is equal to the adjustment period, that is, the refrigeration valve 162 is always in an off-pause state in the whole adjustment period; when the pulse width modulation refrigeration output value is greater than the opening threshold of the refrigeration valve 162, the pulse width modulation refrigeration output value exceeds the opening threshold of the refrigeration valve 162, and the duty cycle off time of the refrigeration valve 162 is calculated by using the formula, and in one adjustment period, after the duty cycle off time is reached, the refrigeration valve 162 is started until the adjustment period is ended.
Step S150: after the duty cycle off period is elapsed in one adjustment period, the segment adjustment control 160 corresponding to the duty cycle off period is started to realize segment adjustment of the box 110.
Note that during heating, the sectionalizing control 160 is a relay 161, the number of which is three, i.e., n=3; during refrigeration, the sectionalizing control 160 is a refrigeration valve 162, which is also three in number, i.e., n=3. Whether during heating or cooling, the duty cycle off-time of the first segment control 160 is less than the duty cycle off-time of the second segment control 160, and the duty cycle off-time of the second segment control 160 is less than the duty cycle off-time of the third segment control 160.
Specifically, step S150 includes three steps, namely:
step S151: in one adjustment period, after the duty cycle of the first segment adjustment control 160 is turned off, the first segment adjustment control 160 is started, and at this time, the first segment adjustment control 160 adjusts the temperature of the box 110.
Step S152: after the duty cycle of the second segment control 160 is turned off, the second segment control 160 is started, and at this time, the first segment control 160 and the second segment control 160 regulate the temperature of the box 110 at the same time.
Step S153: after the duty cycle of the third segment tuning control 160 is turned off, the third segment tuning control 160 is started, and at this time, the first segment tuning control 160, the second segment tuning control 160 and the third segment tuning control 160 perform temperature adjustment on the box 110 at the same time.
In step S150, the three section control pieces 160 may be the relays 161 or the refrigeration valves 162. When the three sectional adjustment controls 160 may be all relays 161, in one adjustment period, after the first relay 161 is turned off for a period of time after the duty ratio of the first relay 161 is turned off, only the first relay 161 heats the case 110, and the starting state of the first relay 161 continues until the adjustment period is finished, while the second and third relays 161 are in a pause state; after the duty cycle of the second relay 161 is turned off, the second relay 161 is started, and at this time, the first and second relays 161 heat the case 110 at the same time, and the start state of the second relay 161 continues until the adjustment period is completed, and the third relay 161 is in a pause state; after the off-period of the duty ratio of the third relay 161, the third relay 161 is activated, and at this time, the first, second and third relays 161 heat the case 110 at the same time, and the activation state of the third relay 161 is continued until the end of the adjustment period. Thus, the three relays 161 cooperate to realize the sectional control of the temperature rise of the case 110, thereby improving the temperature stability in the slow temperature state.
When the three sectional adjustment members 160 may be the refrigeration valves 162, in one adjustment period, after the duty cycle of the first refrigeration valve 162 is turned off, the first refrigeration valve 162 is started, only the first refrigeration valve 162 is used for refrigerating the tank 110, the starting state of the first refrigeration valve 162 is continued until the adjustment period is finished, and the second and third refrigeration valves 162 are in a pause state; after the duty cycle of the second refrigeration valve 162 is turned off, the second refrigeration valve 162 is started, and at this time, the first and second refrigeration valves 162 simultaneously refrigerate the tank 110, and the start state of the second refrigeration valve 162 is continued until the end of the adjustment period, and the third refrigeration valve 162 is in a pause state; after the off period of the duty cycle of the third refrigeration valve 162, the third refrigeration valve 162 is activated, and at this time, the first, second and third refrigeration valves 162 simultaneously cool the tank 110, and the activation state of the third refrigeration valve 162 is continued until the end of the adjustment period. In this way, the three refrigeration valves 162 cooperate to realize the sectional control of the temperature reduction of the tank 110, and improve the temperature stability in the slow temperature state.
It should be noted that, in the temperature control method provided by the present invention, the duty cycle off duration of the segment control 160 is calculated, that is, the segment control 160 is controlled to be paused and then started in one adjustment period, compared with the manner of controlling the segment control 160 to be paused and then started in the prior art, since the temperature adjustment action period of the temperature adjustment device 150 is greater than or even far greater than the calculation period of the PID control module 141, the temperature adjustment device 150 can more accurately execute the pulse width modulation output value calculated and output by the PID control module 141 by adopting the delayed start (pause and start before) manner.
Step S160: and calculating the duty cycle disconnection time length of each segment regulating control 160 again according to the pulse width modulation output value, the regulating period and the opening threshold value of each segment regulating control 160, and entering the next regulating period.
In step S160, when one adjustment period is completed, the polarity of the pwm output value needs to be determined again. If the pwm output value M >0, the duty cycle off duration of each relay 161 is calculated, and the next adjustment cycle is entered, and the plurality of relays 161 are used to heat the tank 110. If the pwm output value m=0, neither the relay 161 nor the refrigeration valve 162 is activated and the next conditioning cycle is entered to keep the temperature of the tank 110 unchanged. If the pwm output value M <0, the duty cycle off duration of each of the refrigeration valves 162 is calculated, and the next adjustment cycle is entered, and the plurality of refrigeration valves 162 are used to cool the tank 110.
According to the temperature control method provided by the embodiment of the invention, firstly, the duty ratio disconnection time length of each segment regulating member 160 is calculated according to the pulse width modulation output value, the regulating period and the opening threshold value of each segment regulating member 160; then, after the duty cycle off period is passed in one adjustment period, the segment adjustment control 160 corresponding to the duty cycle off period is started to realize segment adjustment of the box 110. Compared with the prior art, the temperature control method provided by the invention has the advantages that the step of sectionally regulating the temperature of the box body 110 by the temperature regulating device 150 is realized by adopting the sectionally regulating control 160 corresponding to the duty ratio off-time after the sectionally duty ratio off-time is calculated in one regulating period, so that the sectionally regulating and controlling of the temperature regulating device 150 can be realized by executing the sectionally regulating control 160 with different duty ratios, the stability of the temperature in a slow temperature state is improved, the output oscillation of PID is avoided, the temperature fluctuation is reduced, the temperature uniformity is improved, and the stability and the accuracy of executing the PID output in a fast temperature state are improved.
The technical features and advantageous effects of the present invention are described in further detail below with reference to examples and comparative examples.
Example 1
Referring to fig. 4, a temperature control method according to an embodiment of the present invention is used for heating a case 110 in a slow temperature state.
In embodiment 1, the number of relays 161The amount is three, the total power of the electric heater 151 is divided into three parts by using three relays 161, the power of each relay 161 is 10KW, and the opening threshold S of the first relay 161 M1 =0, the second relay 161 has an open threshold S M2 =30%, the third relay 161 has an open threshold S M3 =60%. When the temperature of the case 110 is kept at 60 ℃, the required heating power is about 300W, and since the heating process is controlled by the segments of the three relays 161, the pulse width modulation output value outputted by the PID control module 141 is 3%, and the first relay 161 is started and both the second and third relays 161 are suspended in a small output regulation state. Specifically, the activation time of the first relay 161 is determined by the duty-cycle off-period of the first relay 161, and after the duty-cycle off-period of the first relay 161 has elapsed in one adjustment period, the first relay 161 is activated until the adjustment period ends.
Example 2
Referring to fig. 5, a temperature control method according to an embodiment of the invention is used for heating a case 110 in a fast temperature change state.
In example 2, the number of relays 161 is three, the total power of the electric heater 151 is divided into three by using three relays 161, the power of each relay 161 is 10KW, and the threshold value S of the opening of the first relay 161 M1 =0, the second relay 161 has an open threshold S M2 =30%, the third relay 161 has an open threshold S M3 =60%. When the temperature of the box 110 is rapidly increased from 60 ℃ to 180 ℃, the required heating power is about 20KW, and the first, second and third relays 161 are all started because the heating process is controlled by the segments of the three relays 161, the pulse width modulation output value output by the PID control module 141 is 80%, and the box is in a large output regulation state. Specifically, the activation time of each relay 161 is determined by the duty-cycle off-time of the relay 161, and in one adjustment period, after the duty-cycle off-time of the first relay 161, the first relay 161 is activated, and after the duty-cycle off-time of the second relay 161, the second relay 161 is activated, and after the duty-cycle off-time of the third relay 161, the first relay 161 is activatedAfter the off period of the duty cycle, the third relay 161 is activated until the end of the adjustment period.
Comparative example 1
Referring to fig. 6, a temperature control method is used to heat the case 110 in a slow temperature state.
In comparative example 1, the case 110 was directly heated by the electric heater 151, and the power of the electric heater 151 was not lower than 30KW. When the temperature of the box 110 is kept at 60 ℃, the required heating power is about 300W, and since the heating process is not controlled by the segment, the pulse width modulation output value output by the PID control module 141 is 1%, and in a very small output adjustment state, if the parameter setting of the PID control module 141 is not nearly perfect (most of the adjustment engineers are difficult to achieve nearly perfect), the actual temperature in the box 110 may be higher than the preset temperature, and at this time, the output of the PID control module 141 is less than 0, and the refrigeration function is started. In this process, since the electric heater 151 and the compression refrigerator 152 have different hysteresis in temperature adjustment, temperature fluctuation is caused, and the temperature fluctuation in turn causes oscillation output from the PID control module 141, so that heating and cooling are switched back and forth.
Comparative example 2
Referring to fig. 7, a temperature control method is used to raise the temperature of the case 110 in a fast-temperature state.
In comparative example 2, the electric heater 151 was directly used to heat the case 110 through three relays 161, the three relays 161 were simultaneously activated or suspended, the sectional temperature adjustment was not performed, and the power of the electric heater 151 was not lower than 30KW. When the temperature of the box 110 is quickly increased from 60 ℃ to 180 ℃, the required heating power is about 25KW, and the pulse width modulation output value output by the PID control module 141 is 90% because the heating process is not regulated and controlled in a sectional mode, so that the box is in a maximum output regulation state, the energy consumption is higher, and the output stability and accuracy of the PID control module 141 are lower.
As is clear from example 1 and comparative example 1, the temperature fluctuation of the temperature control method provided in example 1 is much smaller than that of the temperature control method provided in comparative example 1 when the temperature of the case 110 is adjusted in a slow temperature change state. This means that the temperature stability and uniformity of the temperature control method provided by the embodiment of the invention under the slow temperature state are obviously higher than those of the temperature control method in the prior art.
As can be seen from example 2 and comparative example 2, when the temperature of the case 110 is adjusted in a rapid temperature change state, the output amount of the PID control module 141 increases as the temperature difference increases, and the total output power also increases to satisfy the rapid response of the entire closed loop control. Compared with comparative example 1, the temperature control method provided in example 1 adopts a sectional regulation mode, so that the increase of the output power is greatly reduced, the output stability of the PID control module 141 is facilitated, and the accuracy of the adjustment of the PID control module 141 is improved. This means that the stability and accuracy of the regulation of the PID control module 141 in the temperature control method provided by the embodiment of the present invention are significantly higher than those of the temperature control method in the prior art.
The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (8)
1. The utility model provides a temperature control method, is applied to environmental test case (100), characterized in that, environmental test case (100) include box (110), controller (140), attemperator (150) and two at least segmentation attemperator (160), attemperator (150) through two at least segmentation attemperator (160) with box (110) are connected, in order to attemperate box (110), controller (140) are simultaneously with two at least segmentation attemperator (160) electricity is connected, temperature control method includes:
calculating a pulse width modulation output value according to a preset temperature and an actual temperature in the box body (110);
setting an adjustment period according to a hardware lifetime and a minimum response time of the temperature adjustment device (150) and a calculated frequency of the controller (140);
calculating an opening threshold value of each segmented regulating piece (160) according to the total power of the temperature regulating device (150) and the sub power of each segmented regulating piece (160);
calculating the duty ratio disconnection time length of each segment regulating control (160) according to the pulse width modulation output value, the regulating period and the opening threshold value of each segment regulating control (160), wherein the calculation formula of the duty ratio disconnection time length of the segment regulating control (160) is as follows:
if M is less than or equal to S Mn TS is then Mn ＝T M ；
If M > S Mn Then
Wherein M is the pulse width modulation output value, S Mn Is the opening threshold value, TS, of the nth segment adjustment control (160) Mn For the duty cycle off-time length, T, of the nth segment control (160) M For the adjustment period;
and in one regulating period, after the duty cycle switching-off time length is passed, starting the sectional regulating control (160) corresponding to the duty cycle switching-off time length so as to realize sectional temperature regulation of the box body (110).
2. The temperature control method according to claim 1, wherein the step of calculating the pulse width modulation output value from a preset temperature and an actual temperature within the tank (110) comprises:
inputting the preset temperature into the controller (140) by using a register (120), and acquiring the actual temperature in the box (110) by using a temperature sensor (130) and inputting the actual temperature into the controller (140);
setting a proportional parameter, an integral parameter and a derivative parameter of the controller (140), and setting the pulse width modulation output value output by the controller (140) to be bipolar;
and calculating the pulse width modulation output value.
3. The temperature control method according to claim 2, wherein the controller (140) comprises a PID control module (141) and a plurality of PLC control modules (142), the register (120) and the temperature sensor (130) are electrically connected to the PID control module (141), the PID control module (141) is configured to calculate the pulse width modulation output value, the PID control module (141) is simultaneously electrically connected to a plurality of PLC control modules (142), the plurality of PLC control modules (142) are electrically connected to a plurality of segment control elements (160) in a one-to-one correspondence, and each PLC control module (142) is configured to control one segment control element (160) to perform temperature adjustment.
4. The temperature control method according to claim 1, wherein in the step of calculating the opening threshold value of each of the segment adjustment members (160) according to the total power of the temperature adjustment device (150) and the sub power of each of the segment adjustment members (160), a calculation formula of the opening threshold value of each segment adjustment member (160) is:
S M1 ＝0；
wherein a is a ratio parameter, a ranges from 0.8 to 1.2, S M1 Is the opening threshold value of the first segmented control (160), S Mn Is the opening threshold value of the nth segmented temperature control member (160), QW is the total power of the temperature control device (150), QW 1 For the first of said segmented tuning controls (160) the sub-power, QW n-1 Sub-power for the n-1 th said sectionalized control (160).
5. The temperature control method according to claim 4, wherein a=1, and the calculation formula of the opening threshold value of the segment adjustment control (160) is:
S M1 ＝0；
6. the temperature control method according to claim 1, wherein the number of the segment-wise control members (160) is three, and the duty cycle off-time period of a first segment-wise control member (160) is smaller than the duty cycle off-time period of a second segment-wise control member (160), and the duty cycle off-time period of the second segment-wise control member (160) is smaller than the duty cycle off-time period of a third segment-wise control member (160);
the step of starting the segment adjustment control (160) corresponding to the duty cycle off duration after the duty cycle off duration in one adjustment period to realize segment adjustment of the box (110) comprises the following steps:
starting a first segmented control (160) after the switching-off duration of the duty ratio of the first segmented control (160) in one adjustment period, and adjusting the temperature of the box body (110) by the first segmented control (160);
after the time length of the disconnection of the duty ratio of the second segment adjusting part (160), starting the second segment adjusting part (160), and simultaneously adjusting the temperature of the box body (110) by the first segment adjusting part (160) and the second segment adjusting part (160);
after the time length of disconnection of the duty ratio of the third segmented control (160), starting the third segmented control (160), wherein at the moment, the first segmented control (160), the second segmented control (160) and the third segmented control (160) are used for simultaneously adjusting the temperature of the box body (110).
7. The temperature control method according to claim 1, wherein the temperature regulating device (150) includes an electric heater (151) and a compression refrigerator (152), the step-wise regulating control (160) includes a relay (161) and a refrigerating valve (162), the electric heater (151) is connected to the tank (110) through the relay (161) to heat the tank (110), the compression refrigerator (152) is connected to the tank (110) through the refrigerating valve (162) to cool the tank (110), and the pulse width modulation output value includes a pulse width modulation heating output value and a pulse width modulation refrigerating output value;
when M >0, h=m, l=0, at which time the electric heater (151) and the relay (161) are activated, and the compression refrigerator (152) and the refrigeration valve (162) are not activated;
when m=0, H-L-M-0, at which time none of the electric heater (151), the relay (161), the compression refrigerator (152), and the refrigeration valve (162) is activated;
when M <0, l= -M, h=0, when the electric heater (151) and the relay (161) are not activated, the compression refrigerator (152) and the refrigeration valve (162) are activated;
wherein M is the pulse width modulation output value, M is more than or equal to-100% and less than or equal to 100%, H is the pulse width modulation heating output value, and L is the pulse width modulation refrigeration output value.
8. The temperature control method according to claim 1, wherein after the step of starting the segment adjustment control (160) corresponding to the duty cycle off-period after the duty cycle off-period has elapsed in one of the adjustment periods to achieve segment adjustment of the temperature of the case (110), the temperature control method further comprises:
and calculating the duty ratio disconnection time length of each segment regulating control (160) according to the pulse width modulation output value, the regulating period and the opening threshold value of each segment regulating control (160) again, and entering the next regulating period.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111681784.5A CN114489177B (en) | 2021-12-30 | 2021-12-30 | Temperature control method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111681784.5A CN114489177B (en) | 2021-12-30 | 2021-12-30 | Temperature control method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114489177A CN114489177A (en) | 2022-05-13 |
| CN114489177B true CN114489177B (en) | 2023-05-09 |
Family
ID=81509402
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111681784.5A Active CN114489177B (en) | 2021-12-30 | 2021-12-30 | Temperature control method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114489177B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115079562B (en) * | 2022-07-20 | 2022-11-01 | 中国飞机强度研究所 | Determination method of temperature change control method for testing thermal strength of aerospace plane |
| CN115674769B (en) * | 2022-11-21 | 2023-03-21 | 苏州艾特森制药设备有限公司 | Intelligent preparation control method and equipment for liposome extrusion |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09128062A (en) * | 1995-10-27 | 1997-05-16 | Hitachi Ltd | Pulse width modulation type temperature controller |
| WO2020000150A1 (en) * | 2018-06-25 | 2020-01-02 | 深圳市丽福科技有限责任公司 | Control method and device for electronic cigarette heating temperature |
| CN112214048A (en) * | 2020-09-02 | 2021-01-12 | 重庆邮电大学 | Temperature control system and method for miniature rapid temperature change experiment box |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TW499637B (en) * | 1999-07-19 | 2002-08-21 | Winbond Electronics Corp | Method and apparatus of rotation speed control for heat dissipation fan |
| JP4538852B2 (en) * | 2006-03-27 | 2010-09-08 | 株式会社デンソー | Vehicle control device |
| CN201621910U (en) * | 2010-01-18 | 2010-11-03 | 重庆安吉拉通力实验设备有限公司 | Energy-saving cold side adjusting device of rapid temperature change testing box |
| CN102183978A (en) * | 2011-01-21 | 2011-09-14 | 丹纳赫西特传感工业控制（天津）有限公司 | Self-learning function balanced and unbalanced cooling control method suitable for high-low temperature test cases |
| CN104571219A (en) * | 2014-12-17 | 2015-04-29 | 深圳市华宝电子科技有限公司 | Device and method for automatically controlling temperature of vehicle-mounted equipment |
| KR102196265B1 (en) * | 2017-06-13 | 2020-12-29 | 주식회사 엘지화학 | Method and system for controling temperature of a battery pack |
| CN108490775B (en) * | 2018-03-19 | 2020-12-08 | 上海微小卫星工程中心 | Temperature stability control device and control method for spacecraft |
| US11367645B2 (en) * | 2019-03-13 | 2022-06-21 | Applied Materials, Inc. | Temperature tunable multi-zone electrostatic chuck |
| CN110015696B (en) * | 2019-04-29 | 2021-12-03 | 电子科技大学 | Method for controlling reaction temperature change rate and application of method in synthesis of magnetic nanoparticles |
| CN113249930B (en) * | 2021-04-21 | 2023-04-11 | 海信冰箱有限公司 | Heating control circuit, heating control method, washing machine and dryer |
| CN113652348A (en) * | 2021-07-23 | 2021-11-16 | 广东省科学院健康医学研究所 | PCR amplification system and control method thereof |
-
2021
- 2021-12-30 CN CN202111681784.5A patent/CN114489177B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH09128062A (en) * | 1995-10-27 | 1997-05-16 | Hitachi Ltd | Pulse width modulation type temperature controller |
| WO2020000150A1 (en) * | 2018-06-25 | 2020-01-02 | 深圳市丽福科技有限责任公司 | Control method and device for electronic cigarette heating temperature |
| CN112214048A (en) * | 2020-09-02 | 2021-01-12 | 重庆邮电大学 | Temperature control system and method for miniature rapid temperature change experiment box |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114489177A (en) | 2022-05-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114489177B (en) | Temperature control method | |
| CN108980441B (en) | Proportional electromagnetic valve driving method based on PWM | |
| KR100769238B1 (en) | Temperature control apparatus | |
| CN105783193B (en) | The initial opening control method and device of electric expansion valve | |
| CN105423513B (en) | Power continuously adjustabe electric heating system and its control method | |
| CN101587355A (en) | Temperature control equipment and temperature control method thereof | |
| CN106873663B (en) | A kind of temprature control method and system | |
| CN101789707A (en) | The load balance of the inverter module that is connected in parallel | |
| CN104457073A (en) | Frequency conversion control method | |
| CN111086551A (en) | Steering wheel heating control method based on temperature closed-loop adjustment | |
| CN111485097B (en) | Temperature control device and method for low-temperature heat treatment furnace | |
| CN114061078A (en) | Method and device for controlling air conditioner and multi-split air conditioner | |
| CN109708394B (en) | Control method and control system for cooling fan of refrigerator | |
| Quartarone et al. | Model predictive control: First application of a novel control strategy for adjustable speed drive compressors | |
| CN104833059A (en) | Air conditioner control method and device | |
| CN116538743B (en) | Control method of water chiller | |
| CN113834249A (en) | Automatic adjusting method and system for refrigeration energy of environmental chamber | |
| CN112890616A (en) | Low-temperature amplitude control method for air fryer | |
| CN115291649B (en) | Temperature control method of oven, temperature control method of film wrapping machine, oven and film wrapping machine | |
| CN111196125A (en) | Vehicle-mounted air conditioner, operation method, control device and computer-readable storage medium | |
| CN112904910B (en) | Oven control system and temperature control method thereof | |
| CN112886794B (en) | Control method and control device for high-power high-frequency switching power supply | |
| CN109708391B (en) | Control method and self-adaptive adjusting circuit for cooling fan of refrigerator | |
| JP2002140119A (en) | Work temperature controller | |
| CN216716743U (en) | Adjustable electric heating device for refrigerating unit |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |