Temperature control method and system for double-screw extruder

Abstract

The invention provides a temperature control method and system for a double-screw extruder. The method comprises the steps that the current actual temperature and the set temperature of a target double-screw extruder temperature control system are obtained in real time; determining a temperature return difference area by using the current actual temperature and the set temperature; when the current actual temperature is out of the temperature return difference area and the absolute value of the difference value between the current actual temperature and the set temperature is larger than a preset threshold value, an intermediate set value is calculated through the current actual temperature and the set temperature to serve as a temporary control target so as to guide a PID controller to drive a heating component or a water cooling component; the temperature of the double-screw extruder is accurately adjusted, excessive adjustment caused by too large adjustment amplitude is effectively avoided, the problems of overshoot and undershoot existing in a temperature control system of the double-screw extruder are fundamentally solved, and the temperature control precision and stability of the double-screw extruder are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of equipment temperature control, and particularly relates to a temperature control method and system for a twin-screw extruder. Background Art

[0002] A twin-screw extruder is a commonly used plastic processing equipment. During the operation of the twin-screw extruder, the internal temperature control is an extremely complex and crucial link. Each channel integrates a heating part and a cooling part. This design aims to achieve precise control of the material processing temperature, ensuring the smooth progress of the production process and the stability of product quality.

[0003] Its cooling part adopts the water cooling method, which is based on the unique physical properties of water. When water absorbs heat, it will undergo a phase change and turn into water vapor, and this process will absorb a large amount of heat. In the actual operation of the twin-screw extruder, when the material temperature is too high and needs to be cooled, water flows through the cooling channel, absorbs the heat of the material through heat exchange, and the water vaporizes to form water vapor, thereby effectively reducing the temperature of the material. However, this cooling method also has certain disadvantages. Since the water vapor will cause a large drop in temperature after absorbing a large amount of heat, if the control of the cooling system is not precise enough, it is easy to cause the material temperature to drop excessively, deviate from the set process temperature range, and thus affect the product quality.

[0004] In addition, the channels of the twin-screw extruder are closely connected. Although this helps to a certain extent with the compactness of the overall structure and the heat conduction efficiency, it also brings the problem of temperature crosstalk. Temperature crosstalk means that the temperature change of one channel will affect the temperature of adjacent channels. When a certain channel is heated, the heat will be transferred to adjacent channels through structures such as the barrel wall; similarly, during the cooling process, the low temperature may also spread to the surrounding channels. This temperature crosstalk will cause a deviation between the actual temperature and the set temperature of each channel, increasing the difficulty of temperature control.

[0005] The traditional PID control technology is widely used in the temperature control of twin-screw extruders. In some occasions where the requirements for temperature control accuracy are not high, PID control can meet the basic needs. However, for a temperature control system with complex characteristics such as large lag and nonlinearity like a twin-screw extruder, PID control has problems such as large overshoot and slow response speed. When the material characteristics change, it is difficult to adjust the PID parameters in real time, resulting in poor temperature control effects.

[0006] To address these issues, continuous innovation and optimization are needed in temperature control technology. On the one hand, the control strategy of the cooling system should be improved. Through precise flow control and temperature feedback mechanisms, the stability and accuracy of the cooling process can be ensured, and excessive temperature drops can be avoided. However, for the large-lag temperature control system of a twin-screw extruder, there is an obvious delay in the system's response to temperature adjustment commands. When the difference between the temperature set value (SV) and the current value (PV) is large, overshoot or undershoot phenomena are likely to occur, seriously affecting the temperature control accuracy and system stability, reducing production efficiency and product quality, and increasing energy consumption and equipment wear. Summary of the Invention

[0007] The present invention provides a temperature control method and system for a twin-screw extruder, aiming to solve the overshoot and undershoot problems in the temperature control system of the twin-screw extruder and improve the temperature control accuracy and stability of the twin-screw extruder.

[0008] To achieve the above object, the present invention provides a temperature control method for a twin-screw extruder. The twin-screw extruder includes a heating component and a water-cooling component, and both the heating component and the water-cooling component are controlled by a PID controller. The temperature control method includes:

[0009] Obtain the current actual temperature and the set temperature of the temperature control system of the target twin-screw extruder in real time;

[0010] Determine the temperature deadband region based on the current actual temperature and the set temperature;

[0011] When the current actual temperature is outside the temperature deadband region and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculate an intermediate set value as a temporary control target through the current actual temperature and the set temperature, so as to guide and drive the heating component or the water-cooling component by the PID controller to achieve precise adjustment of the temperature of the twin-screw extruder.

[0012] Furthermore, the current actual temperature of the temperature control system of the target twin-screw extruder is obtained through the thermocouple of the twin-screw extruder.

[0013] Furthermore, the temperature deadband region includes a heating temperature deadband region and a cooling temperature deadband region;

[0014] When the current actual temperature is less than the set temperature and the current actual temperature is greater than a first preset threshold, it is determined that the current actual temperature is in the heating temperature deadband region, and the heating temperature deadband region is between the first preset threshold and the set temperature;

[0015] When the current actual temperature is greater than the set temperature and the current actual temperature is less than a second preset threshold, it is determined that the current actual temperature is in the cooling temperature deadband region, and the cooling temperature deadband region is between the set temperature and the second preset threshold.

[0016] Furthermore, when the current actual temperature is outside the temperature dead zone and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, an intermediate set value is calculated from the current actual temperature and the set temperature as a temporary control target, including:

[0017] When the current actual temperature is outside the heating temperature dead zone or the cooling temperature dead zone and the absolute value of the difference between the current actual temperature and the set temperature is greater than a third preset threshold, an intermediate set value is calculated from the current actual temperature and the set temperature as a temporary control target.

[0018] Furthermore, the calculation formula for the intermediate set value is:

[0019] sv MID = pv + (sv - pv)·ratio

[0020] where sv MID represents the intermediate set value, pv represents the current actual temperature, sv represents the set temperature, and ratio represents the set coefficient.

[0021] Furthermore, guiding the PID controller to drive the heating component or the water cooling component includes:

[0022] When the current actual temperature is within the heating temperature dead zone or the cooling temperature dead zone, the PID control is not switched;

[0023] When the current actual temperature is less than the set temperature and the current actual temperature is less than a first preset threshold, it is determined that the current actual temperature is outside the heating temperature dead zone, and the PID controller is guided to drive the heating component;

[0024] When the current actual temperature is greater than the set temperature and the current actual temperature is greater than a second preset threshold, it is determined that the current actual temperature is outside the cooling temperature dead zone, and the PID controller is guided to drive the cooling component.

[0025] Furthermore, the termination conditions for guiding the PID controller to drive the heating component or the cooling component to adjust the temperature are:

[0026] The absolute value of the difference between the current actual temperature and the set temperature is less than a third preset threshold;

[0027] Within a continuous time interval, the volatility of the current actual temperature is less than a preset threshold.

[0028] The present invention also provides a temperature control system for a twin-screw extruder, including the temperature control method for the twin-screw extruder.

[0029] The above solution of the present invention has the following beneficial effects:

[0030] Compared with the prior art, the present invention obtains the current actual temperature and the set temperature of the temperature control system of the target twin-screw extruder in real time; determines the temperature dead zone based on the current actual temperature and the set temperature; when the current actual temperature is outside the temperature dead zone and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculates an intermediate set value as a temporary control target through the current actual temperature and the set temperature, so as to guide the PID controller to drive the heating component or the water-cooling component, realizing precise adjustment of the temperature of the twin-screw extruder, effectively avoiding overshoot caused by excessive adjustment amplitude, fundamentally solving the overshoot and undershoot problems existing in the temperature control system of the twin-screw extruder, and improving the temperature control accuracy and stability of the twin-screw extruder.

[0031] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation part. Brief Description of the Drawings

[0032] Figure 1 It is a schematic diagram of the temperature control system of the twin-screw extruder;

[0033] Figure 2 It is a schematic flowchart of an embodiment of the present invention;

[0034] Figure 3 It is a schematic diagram of the temperature dead zone in an embodiment of the present invention;

[0035] Figure 4 It is a schematic diagram of the change process of the temperature curve and the control quantity curve in an embodiment of the present invention;

[0036] Figure 5 It is a temperature change curve graph of the traditional PID control and the control method of the present invention during the heating process;

[0037] Figure 6 It is a temperature change curve graph of the two control methods during the cooling process. Detailed Description of the Invention

[0038] To make the technical problems, technical solutions and advantages to be solved by the present invention clearer, the following will be described in detail with reference to the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0039] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0040] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a locking connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0041] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] The present invention provides a temperature control method and system for a twin-screw extruder in view of existing problems.

[0043] As Figure 1 、 2 shown, an embodiment of the present invention provides a temperature control method for a twin-screw extruder. The twin-screw extruder includes a heating component and a water-cooling component, and both the heating component and the water-cooling component are controlled by a PID controller. The temperature control method includes:

[0044] Step 1, obtaining the current actual temperature and the set temperature of the temperature control system of the target twin-screw extruder in real time;

[0045] Step 2, determining the temperature dead zone by using the current actual temperature and the set temperature;

[0046] Step 3, when the current actual temperature is outside the temperature dead zone and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculating an intermediate set value as a temporary control target through the current actual temperature and the set temperature, so as to guide the PID controller to drive the heating component or the water-cooling component to achieve precise adjustment of the temperature of the twin-screw extruder.

[0047] Specifically, the current actual temperature of the temperature control system of the target twin-screw extruder is obtained through the thermocouple of the twin-screw extruder.

[0048] It should be noted that the mathematical expression of the PID controller is as follows:

[0049]

[0050] where output represents the control quantity output by the PID controller, K p represents the proportional coefficient, K i represents the integral coefficient, K d represents the differential coefficient. The values of the proportional, integral, and differential coefficients play a key role in the control effect of the PID controller. Usually, they need to be determined through rigorous debugging according to the characteristics of the specific temperature control system. sv represents the set temperature, and pv represents the current actual temperature. The difference between the set temperature and the current actual temperature and its change situation determine the adjustment direction and amplitude of the control output.

[0051] In the embodiment of the present invention, the temperature sensor is connected to the thermocouple of the twin-screw extruder to collect the current actual temperature of the temperature control system of the target twin-screw extruder, which is used to reflect the actual temperature situation of the temperature control system of the target twin-screw extruder at any time.

[0052] Specifically, as Figure 3 shown, the temperature hysteresis region includes the heating temperature hysteresis region Zone1 and the cooling temperature hysteresis region Zone2;

[0053] When the current actual temperature is less than the set temperature and greater than the first preset threshold, it is determined that the current actual temperature is in the heating temperature hysteresis region Zone1, and the heating temperature hysteresis region Zone1 is located between the first preset threshold and the set temperature;

[0054] When the current actual temperature is greater than the set temperature and less than the second preset threshold, it is determined that the current actual temperature is in the cooling temperature hysteresis region Zone2, and the cooling temperature hysteresis region Zone2 is located between the set temperature and the second preset threshold.

[0055] Specifically, when the current actual temperature is outside the temperature hysteresis region and the absolute value of the difference between the current actual temperature and the set temperature is greater than the preset threshold, the intermediate set value is calculated through the current actual temperature and the set temperature as the temporary control target, including:

[0056] When the current actual temperature is outside the heating temperature hysteresis region or the cooling temperature hysteresis region and the absolute value of the difference between the current actual temperature and the set temperature is greater than the third preset threshold, the intermediate set value is calculated through the current actual temperature and the set temperature as the temporary control target.

[0057] Before the intermediate set value is calculated by the temperature control system of the target twin-screw extruder as a temporary control target in the embodiments of the present invention, it is necessary to use a judgment function to judge the stability state of the temperature control system of the target twin-screw extruder, and decide whether to start the intermediate set value according to the judgment result to guide the PID controller to drive the heating component or the cooling component to adjust the temperature. The expression of the judgment function is:

[0058] if pv(t) == pv(t-T) and |sv-pv| ≥ threshold

[0059] Wherein, T represents the time interval, which is a fixed time period for monitoring the temperature change situation. By comparing the temperature data within different time intervals, the change trend and stability state of the system temperature are judged. t represents the current moment during the operation of the system, serving as a reference point in the time dimension to facilitate recording and analyzing the temperature-related parameters and state changes of the system at different moments. threshold represents the third preset threshold.

[0060] This judgment process means that within a specific time interval T, if the current actual temperature pv remains the same at time t and time t-T, and the third preset threshold is an important threshold for judging the temperature difference magnitude. When the absolute value of the difference |SV-PV| between the current actual temperature and the set temperature is greater than the third preset threshold, it is determined that the temperature control system of the target twin-screw extruder has not reached a stable state, indicating that the temperature adjustment process still needs to continue, and then subsequent control operations such as intermediate set value adjustment are triggered to promote the temperature to further approach the set value.

[0061] In the embodiments of the present invention, the intermediate set value, as a temporarily set temperature value, is calculated according to the real-time state of the temperature control system and established rules during the temperature control process of the target twin-screw extruder, and serves as a phased control target to guide a more stable temperature adjustment. The calculation formula of the intermediate set value is:

[0062] sv MID = pv+(sv-pv)·ratio

[0063] Wherein, sv MID represents the intermediate set value, pv represents the current actual temperature, sv represents the set temperature, and ratio represents the set coefficient.

[0064] In the embodiments of the present invention, the set coefficient serves as a key coefficient for control adjustment, and its value range is usually determined according to the system characteristics and actual debugging conditions. In the embodiments of the present invention, it is set to 1 / 2 to reasonably allocate the amplitude of each temperature adjustment.

[0065] Specifically, guiding the PID controller to drive the heating component or the water-cooling component includes:

[0066] When the current actual temperature is in the heating temperature dead zone Zone1 or the cooling temperature dead zone Zone2, the PID control is not switched.

[0067] When the current actual temperature is less than the set temperature and the current actual temperature is less than the first preset threshold, it is determined that the current actual temperature is outside the heating temperature dead zone Zone1, and the PID controller is guided to drive the heating component.

[0068] When the current actual temperature is greater than the set temperature and the current actual temperature is greater than the second preset threshold, it is determined that the current actual temperature is outside the cooling temperature dead zone Zone2, and the PID controller is guided to drive the cooling component.

[0069] Specifically, the termination conditions for guiding the PID controller to drive the heating component or the cooling component for temperature adjustment are:

[0070] The absolute value of the difference between the current actual temperature and the set temperature is less than the third preset threshold;

[0071] Within a continuous time interval, the volatility of the current actual temperature is less than the preset threshold.

[0072] Since after each new intermediate set value is calculated, the temperature control system of the target twin-screw extruder immediately substitutes this intermediate set value into the control function of the PID controller to drive the corresponding heating component or cooling component for polar temperature adjustment operations, and this temperature adjustment process will continue to cycle until the termination conditions are met, that is, the stable determination conditions are met. The termination conditions for guiding the PID controller to drive the heating component or the cooling component for temperature adjustment are:

[0073] The absolute value of the difference between the current actual temperature and the set temperature gradually shrinks until it is less than the third preset threshold, which indicates that the current actual temperature has approached the set temperature and is within a reasonable control error range;

[0074] From the perspective of the temperature change trend, within a continuous time interval, the volatility of the current actual temperature is less than the preset threshold, that is, there is no obvious change or fluctuation, which means that the current actual temperature has approached a stable state and meets the requirements of stable control.

[0075] In order to more intuitively demonstrate the effectiveness of the control method provided by the embodiments of the present invention, the heating process of the twin-screw extruder is taken as a specific example for detailed description:

[0076] Suppose in a chemical production process, the set temperature SV of the temperature control system of a twin-screw extruder is 200 °C, the current actual temperature PV is 170 °C, the first preset threshold is 10 °C, the set coefficient is 1 / 2, the heating temperature deadband region Zone1 is 3 °C, the cooling temperature deadband region Zone2 is 2 °C, the PID control function of the heating component is PID_heating, the PID control function of the cooling component is PID_Cooling, the time interval is T = 10 s, and the intermediate set value SV_MID = absolute_zero.

[0077] Calculate the difference between the current actual temperature and the set temperature: ∣SV - PV∣ = ∣200 - 170∣ = 30 °C. Since 30 °C > 10 °C (the third preset threshold), it is necessary to start the intermediate set value adjustment mechanism;

[0078] Calculate the intermediate set value according to the formula SV_MID = PV + (SV - PV) × ratio. Substitute PV = 170 °C, SV = 200 °C, and ratio = 1 / 2 to get: SV_MID = 170 + (200 - 170) / 2 = 170 + 15 = 185 °C.

[0079] Compare the current temperature PV = 170 °C with SV_MID - Zone1 = 185 - 3 = 182 °C. Since 170 °C < 182 °C (the first preset threshold), the control variable MV output by the PID controller at this time is calculated by PID_Heating, and the system starts to heat up with 185 °C as the target.

[0080] As Figure 4 shown, the PID control function calculates according to the deviation between the current actual temperature of 170 °C and the intermediate set value of 185 °C. The PID_Heating of the heating component outputs a control variable according to the current deviation. The larger the deviation, the larger the output of PID_Heating, prompting the heating component to heat up quickly;

[0081] In the initial stage, the control variable MV output by PID_Heating is 100%. As the temperature gradually approaches 185 °C, the control variable MV gradually decreases. When the temperature exceeds 187 °C (the second preset threshold), that is, SV_MID + Zone2 = 187 °C, the control variable MV output at this time is calculated by the PID_Cooling of the cooling component. As Figure 4 shown at point C, this is the control variable output by the PID_Cooling of the cooling component, which cools down the equipment. The control variable output by the PID_Cooling of the cooling component gradually increases, and the maximum output control variable reaches -10%. Then the temperature slowly drops. When PV is less than 182 °C, as Figure 4 shown at point D, the control variable MV output at this time is calculated by PID_Heating;

[0082] When reaching point A, the determination logic is satisfied at this time, and the re - set intermediate set value SV_MID2 is set. The current actual temperature PV = 185°C.

[0083] Calculate the difference between the current actual temperature and the set temperature: ∣SV - PV∣ = ∣200 - 185∣ = 15°C. Since 15°C > 10°C (the third preset threshold), it is necessary to start the intermediate set value adjustment mechanism;

[0084] Calculate the intermediate set value according to the formula SV_MID = PV+(SV - PV)×ratio. Substitute PV = 185°C, SV = 200, and ratio = 1 / 2 into it: SV_MID = 185+(200 - 185) / 2 = 185 + 7.5 = 192.5°C;

[0085] Compare the current actual temperature PV = 185°C with SV_MID - Zone1 = 192.2 - 3 = 189.5°C (the first preset threshold). Since 185°C < 189.5°C, the control variable MV output at this time is obtained by PID_Heating calculation, and the system starts to heat up with 192.5°C as the target.

[0086] As the temperature continuously approaches the intermediate set value, when the temperature approaches 192.5, the PID control function will further reduce the output control variable MV. Since the third preset threshold is 10°C, when the current actual temperature PV is greater than 190°C, at this time ∣SV - PV∣ is less than the third preset threshold 10°C, such as Figure 4 at point E. At this time, the determination logic is not satisfied, and the intermediate set value is changed from SV_MID (192.5°C) to SV (200°C). As can be seen from Figure 4 it, there is a step change in the output control variable. At this time, the output control variable is 70%. As the temperature gradually approaches the set value, the output control variable MV gradually decreases. Until finally, when PV stabilizes near SV, the output control variable MV also gradually stabilizes at 40%.

[0087] From Figure 4 it can be seen that there is a step change in the control variable MV, until finally it stabilizes near SV. The temperature does not directly approach the set temperature in a violently fluctuating manner, but gradually and stably approaches the set value like along a series of gentle steps, and the adjustment amplitude of each time gradually decreases as the control process progresses. This characteristic essentially avoids the common large - amplitude overshoot and undershoot phenomena in traditional control methods, laying a solid foundation for achieving high - precision and high - stability temperature control effects.

[0088] In order to verify the effect of the method provided in the embodiment of the present invention, a comparative experiment is set up for verification. The experimental results are as Figure 5and Figure 6 as shown Figure 5 when SV > PV, curve 1 represents the control effect of traditional PID control, and curve 2 represents the control effect after using this solution. Figure 5 Compared with the traditional PID control effect, two intermediate set values are added to the control process of curve 2. During the heating process and the stable process, the fluctuation range is smaller and the adjustment time is shorter. Figure 6 when SV < PV, curve 1 represents the control effect of traditional PID control, and curve 2 represents the control effect after using this solution. Figure 6 Compared with the traditional PID control effect, two intermediate set values are added to the control process of curve 2. During the cooling process and the stable process, the fluctuation range is smaller and the adjustment time is shorter.

[0089] In summary, compared with the prior art, the embodiment of the present invention obtains the current actual temperature and the set temperature of the temperature control system of the target twin-screw extruder in real time; determines the temperature dead zone according to the current actual temperature and the set temperature; when the current actual temperature is outside the temperature dead zone and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculates an intermediate set value as a temporary control target through the current actual temperature and the set temperature, so as to guide the PID controller to drive the heating component or the water cooling component, realizing precise adjustment of the temperature of the twin-screw extruder, effectively avoiding overshoot caused by too large adjustment amplitude, fundamentally solving the overshoot and undershoot problems existing in the temperature control system of the twin-screw extruder, and improving the temperature control accuracy and stability of the twin-screw extruder.

[0090] The embodiment of the present invention also provides a temperature control system for a twin-screw extruder, including a temperature control method for the twin-screw extruder.

[0091] It should be noted that since the above system and the method embodiment of the present application are based on the same concept, for the content such as information interaction and execution process inside the above system, its specific functions and the technical effects brought, please refer to the method embodiment part for details, and will not be elaborated here.

[0092] Those skilled in the art can clearly understand that in practical applications, the above system can be allocated to be completed by different functional units and modules according to needs, that is, the internal structure of the system is divided into different functional units or modules to complete all the method steps corresponding to the above method. It can be implemented in the form of hardware or in the form of software functional units. The specific working process of the above system can refer to the corresponding process in the foregoing method embodiment, and will not be elaborated here.

[0093] The above are the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A temperature control method for a twin-screw extruder, characterized in that, The twin-screw extruder includes a heating component and a water-cooling component, and both the heating component and the water-cooling component are controlled by a PID controller. The temperature control method includes: Obtaining the current actual temperature and the set temperature of the temperature control system of the target twin-screw extruder in real time; Determining the temperature deadband region by using the current actual temperature and the set temperature; When the current actual temperature is outside the temperature deadband region and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculating an intermediate set value as a temporary control target through the current actual temperature and the set temperature, so as to guide the PID controller to drive the heating component or the water-cooling component to achieve precise adjustment of the temperature of the twin-screw extruder.

2. The temperature control method for a twin-screw extruder according to claim 1, wherein the current actual temperature of the temperature control system of the target twin-screw extruder is obtained through a thermocouple of the twin-screw extruder.

3. The temperature control method for a twin-screw extruder according to claim 2, wherein, The temperature deadband region includes a heating temperature deadband region and a cooling temperature deadband region; When the current actual temperature is less than the set temperature and the current actual temperature is greater than a first preset threshold, it is determined that the current actual temperature is in the heating temperature deadband region, and the heating temperature deadband region is between the first preset threshold and the set temperature; When the current actual temperature is greater than the set temperature and the current actual temperature is less than a second preset threshold, it is determined that the current actual temperature is in the cooling temperature deadband region, and the cooling temperature deadband region is between the set temperature and the second preset threshold.

4. The temperature control method for a twin-screw extruder according to claim 3, characterized in that, When the current actual temperature is outside the temperature deadband region and the absolute value of the difference between the current actual temperature and the set temperature is greater than a preset threshold, calculating an intermediate set value as a temporary control target through the current actual temperature and the set temperature includes: When the current actual temperature is outside the heating temperature deadband region or the cooling temperature deadband region and the absolute value of the difference between the current actual temperature and the set temperature is greater than a third preset threshold, calculating an intermediate set value as a temporary control target through the current actual temperature and the set temperature.

5. The temperature control method for a twin-screw extruder according to claim 4, characterized in that, The calculation formula of the intermediate set value is: sv MID = pv + (sv - pv) · ratio Among them, sv MID represents the intermediate set value, pv represents the current actual temperature, sv represents the set temperature, and ratio represents the set coefficient.

6. The temperature control method for a twin-screw extruder according to claim 5, wherein Guiding the PID controller to drive the heating component or the water-cooling component includes: When the current actual temperature is in the heating temperature deadband region or the cooling temperature deadband region, the PID control is not switched; When the current actual temperature is less than the set temperature and the current actual temperature is less than a first preset threshold, it is determined that the current actual temperature is outside the heating temperature deadband region, and the PID controller is guided to drive the heating component; When the current actual temperature is greater than the set temperature and the current actual temperature is greater than a second preset threshold, it is determined that the current actual temperature is outside the cooling temperature deadband region, and the PID controller is guided to drive the cooling component.

7. The temperature control method for a twin-screw extruder according to claim 6, characterized in that, The termination conditions for guiding the PID controller to drive the heating component or the cooling component to adjust the temperature are: the absolute value of the difference between the current actual temperature and the set temperature is less than a third preset threshold; within a continuous time interval, the volatility of the current actual temperature is less than a preset threshold.

8. A temperature control system for a twin-screw extruder, characterized in that, Comprising the temperature control method for a twin-screw extruder according to any one of claims 1-7.

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