Multi-region cooperative control method and system for temperature field of carbon nanotube CVD (chemical vapor deposition) growth furnace

Abstract

The invention relates to the technical field of control systems, and discloses a multi-zone cooperative control method and system for a temperature field of a carbon nanotube CVD growth furnace, and the method comprises the steps: obtaining the real-time temperatures of a plurality of temperature zones, and calculating the temperature deviation of each temperature zone; the actual temperature gradient is calculated, if the change rate of the actual temperature gradient exceeds a preset threshold value, the gradient maintaining deviation is calculated, and otherwise, the gradient maintaining deviation is zero; calculating a gain weight; calculating predictive thermal disturbance compensation amount of each temperature zone; calculating a first control item; the predictive thermal disturbance compensation amount forms a second control item; the gradient feed-forward correction value forms a third control item, and the gradient feed-forward correction value is proportional to the gradient maintenance deviation of the temperature zone; and taking the sum of the first control item, the second control item and the third control item as the power control quantity of the temperature zone. Unification and coordination of local temperature control and overall temperature are realized, a stable thermal environment is provided for growth of the carbon nanotubes, and consistency and uniformity of growth of the carbon nanotubes are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of control system, and particularly relates to a carbon nanotube CVD growth furnace temperature field multi-region collaborative control method and system. BACKGROUND

[0002] Chemical vapor deposition (CVD) is the mainstream technology for industrial production of high-quality carbon nanotubes. In the CVD growth process of carbon nanotubes, the temperature distribution in the furnace tube is the core process parameter that determines the key characteristics such as the final morphology, purity and growth rate. To meet the stringent requirements of temperature in different growth stages, modern CVD equipment generally adopts a multi-temperature zone series design. By independently adjusting the heating power of each heating unit arranged along the axial direction of the furnace tube, a specific temperature profile can be accurately constructed, such as forming a complex temperature gradient containing a stable growth zone and a rapid cooling zone.

[0003] However, due to the combined effects of heat conduction, convection and radiation, there is a significant thermal coupling effect between each temperature zone. This means that adjusting the heating power of any temperature zone will inevitably cause thermal disturbance to the adjacent temperature zone. This characteristic of mutual influence makes the system control complex and easily causes temperature overshoot or long-time oscillation, thereby making it difficult to quickly and stably establish and maintain the ideal temperature profile.

[0004] The main limitation of the current control strategy is that it focuses on the accurate tracking of the single-point temperature of each temperature zone, but ignores the direct monitoring and maintenance of the temperature gradient between the temperature zones. Therefore, when the system is disturbed, the difference in response speed of each temperature zone will cause fluctuations in the key temperature gradient. This unstable temperature gradient will directly affect the uniformity and consistency of carbon nanotube growth, ultimately damaging the overall performance and reliability of the product. SUMMARY

[0005] The present application provides a carbon nanotube CVD growth furnace temperature field multi-region collaborative control method and system to solve the problem of poor stability of the temperature gradient in the prior art, which leads to poor uniformity and consistency of carbon nanotube growth.

[0006] In a first aspect, the carbon nanotube CVD growth furnace temperature field multi-region collaborative control method of the present application comprises the following steps: Obtaining the real-time temperature of a plurality of temperature zones distributed along the axial direction of the growth furnace, and calculating the temperature deviation of each temperature zone according to the preset target temperature distribution; Calculate the actual temperature gradient between each temperature zone and its adjacent temperature zones. If the rate of change of the actual temperature gradient exceeds a preset threshold, calculate the gradient maintenance deviation based on the difference between the actual temperature gradient and the target temperature gradient; otherwise, the gradient maintenance deviation is zero. Based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of its adjacent temperature zones, calculate the gain weight of the proportional-integral control output. Based on the influence factor matrix of thermal correlation between multiple temperature zones and the historical power output of other temperature zones, the predictive thermal disturbance compensation amount for each temperature zone is calculated. The temperature deviation of the temperature zone is processed by a proportional-integral controller, and the output of the proportional-integral control is adjusted by gain weight to obtain the first control term; the predictive thermal disturbance compensation amount constitutes the second control term; the gradient feedforward correction amount constitutes the third control term, which is proportional to the gradient maintenance deviation of the temperature zone; the sum of the first control term, the second control term and the third control term is used as the power control amount of the temperature zone.

[0007] Preferably, the actual temperature gradient is calculated using the following formula: ; Where i is greater than or equal to 2 and less than or equal to N, and N is the total number of temperature zones; Let be the actual temperature gradient of the i-th temperature zone at time t. Let be the distance between the center points of the i-th temperature zone and the (i-1)-th temperature zone. Let t be the real-time temperature of the i-th temperature zone; Let t be the real-time temperature of the (i-1)th temperature zone.

[0008] Preferably, if the rate of change of the actual temperature gradient exceeds a preset threshold, the gradient maintenance deviation is calculated based on the difference between the actual temperature gradient and the target temperature gradient, including: The rate of change of the actual temperature gradient is calculated using the following formula: ; in, The actual temperature gradient of the i-th temperature zone during the sampling period Rate of change within; Let t be the actual temperature gradient of the i-th temperature zone; For a moment At that time, the actual temperature gradient of the i-th temperature zone; The sampling period; when When the gradient maintenance bias exceeds a preset threshold, the gradient maintenance bias is calculated using the following formula: ,in, To maintain the gradient deviation for the i-th temperature zone, is the actual temperature gradient of the i-th temperature zone at time t, is the target temperature gradient.

[0009] Preferably, calculating the gain weight of the proportional-integral control output based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of its adjacent temperature zones includes: When 1 < i < N, where N is the total number of temperature zones, the gain weight of the i-th temperature zone is calculated by the following formula ; ; where, is the attenuation coefficient, is the gradient maintenance deviation of the i-th temperature zone, is the gradient maintenance deviation of the (i + 1)-th temperature zone; When i = 1, the gain weight of the first temperature zone is calculated by the following formula ; ; where, is the attenuation coefficient, is the gradient maintenance deviation of the second temperature zone; When i = N, where N is the total number of temperature zones, the gain weight of the N-th temperature zone is calculated by the following formula ; ; where, is the attenuation coefficient, [[ID=4))is the gradient maintenance deviation of the N-th temperature zone.

[0010] Preferably, calculating the predictive thermal disturbance compensation amount for each temperature zone based on the influence factor matrix of the thermal correlation relationship between multiple temperature zones and the historical power output of other temperature zones includes: Establish a dimensional influence factor matrix H, where N is the total number of temperature zones, and the matrix element represents the steady-state influence coefficient of the unit power change of the j-th temperature zone on the temperature of the i-th temperature zone, and the diagonal element represents the steady-state influence coefficient of the i-th temperature zone itself; Calculate the predictive thermal disturbance compensation amount of the i-th temperature zone at time t through the following formula ; ; where, is the power output of the j-th temperature zone at time, is the power output of the j-th temperature zone at time, is the sampling period.

[0011] Preferably, the first control term is calculated by the following formula: wherein, is the first control term of the i-th temperature zone at time t, is the gain weight of the i-th temperature zone, is the proportional coefficient, is the temperature deviation of the i-th temperature zone at time t, is the integral coefficient, is the integral of the temperature deviation of the i-th temperature zone.

[0012] Preferably, the gradient feedforward correction quantity is calculated by the following formula: gradient feedforward correction quantity of the first temperature zone at time t ; When , ; wherein, is the gradient feedforward correction quantity of the i-th temperature zone at time t, is the feedforward coefficient, is the gradient maintenance deviation of the i-th temperature zone.

[0013] Preferably, the real-time temperature of the plurality of temperature zones distributed along the axis of the growth furnace is obtained by arranging temperature sensors in each temperature zone of the growth furnace and collecting the real-time temperature of each temperature zone.

[0014] Preferably, the temperature deviation is the difference between the target temperature and the real-time temperature.

[0015] In a second aspect, the carbon nanotube CVD growth furnace temperature field multi-region collaborative control system of the present application comprises a memory and a processor, and the memory stores computer instructions. When the processor executes the computer instructions, the carbon nanotube CVD growth furnace temperature field multi-region collaborative control method described above is realized.

[0016] The present application has the following advantages: the present application can pre-compensate the thermal disturbance of adjacent temperature zones through predictive thermal disturbance compensation based on the influence factor matrix, can overcome the temperature overshoot and oscillation problem caused by the thermal coupling of traditional independent control, and can improve the stability speed of the temperature field. Furthermore, the present application takes the temperature gradient between the temperature zones as the control object, can maintain the temperature gradient stability of the key process section through calculating the gradient maintenance deviation and introducing the gradient feedforward correction quantity, and can avoid the gradient drastic fluctuation caused by disturbance. In addition, through the gain weight collaborative adjustment of the control output of each temperature zone based on the gradient state of adjacent temperature zones, the unity and coordination of local temperature control and overall temperature are ensured, a more accurate and stable thermal environment is provided for carbon nanotube growth, and the consistency and quality of carbon nanotube growth are improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1A flowchart of a carbon nanotube CVD growth furnace temperature field multi-region collaborative control method provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0018] Embodiments of the present application are described in detail below with reference to examples shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.

[0019] As shown in Figure 1 An embodiment of the carbon nanotube CVD growth furnace temperature field multi-region collaborative control method provided by the present application includes the following steps: S1, acquiring real-time temperatures of a plurality of temperature zones distributed along the axial direction of the growth furnace, and calculating temperature deviations of each temperature zone according to a preset target temperature distribution.

[0020] Specifically, a temperature sensor such as a thermocouple is arranged inside or near each temperature zone of the growth furnace to collect the real-time temperature of each temperature zone. At the same time, an ideal temperature distribution curve along the axial direction of the growth furnace, i.e., a target temperature distribution, is preset according to process requirements, so as to obtain the target temperature of each temperature zone. For each temperature zone, the target temperature is subtracted from the real-time temperature to obtain the temperature deviation of the temperature zone.

[0021] S2, calculating the actual temperature gradient between each temperature zone and the adjacent temperature zone, if the change rate of the actual temperature gradient exceeds a preset threshold, then calculating the gradient maintenance deviation according to the difference between the actual temperature gradient and the target temperature gradient, otherwise the gradient maintenance deviation is zero; based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of the adjacent temperature zone, the gain weight of the adjustment proportional-integral control output is calculated.

[0022] Specifically, the actual temperature gradient is calculated by the following formula: ; Wherein, i is greater than or equal to 2, and i is less than or equal to N, N is the total number of temperature zones; is the actual temperature gradient of the i-th temperature zone at time t, is the distance between the center points of the i-th temperature zone and the i-1-th temperature zone, is the real-time temperature of the i-th temperature zone at time t; is the real-time temperature of the i-1-th temperature zone at time t.

[0023] If the change rate of the actual temperature gradient exceeds the preset threshold, then the gradient maintenance deviation is calculated according to the difference between the actual temperature gradient and the target temperature gradient, including: The change rate of the actual temperature gradient is calculated by the following formula: ; Wherein, is the change rate of the actual temperature gradient in the i-th temperature zone within the sampling period ; is the actual temperature gradient of the i-th temperature zone at time t; is at time the actual temperature gradient of the i-th temperature zone; is the sampling period; When is greater than the preset threshold, the gradient maintenance deviation is calculated by the following formula: , wherein, is the gradient maintenance deviation of the i-th temperature zone, is the actual temperature gradient of the i-th temperature zone at time t, is the target temperature gradient.

[0024] Exemplarily, in a growth furnace with five temperature zones, for the actual temperature gradient between the third temperature zone and the second temperature zone, assuming the distance L between the central points of the two temperature zones is 10 cm, the target temperature gradient is 5 degrees Celsius per centimeter, and the sampling period is 1 second. At the current time t, the measured real-time temperature of the second temperature zone is 200 degrees Celsius, and the real-time temperature of the third temperature zone is 252 degrees Celsius, then the current actual temperature gradient is 5.2 degrees Celsius per centimeter. At the previous sampling moment t-〖1〗, the real-time temperature of the second temperature zone is 200 degrees Celsius, and the real-time temperature of the third temperature zone is 245 degrees Celsius. The actual temperature gradient at the previous moment is calculated as 4.5 degrees Celsius per centimeter. The calculated change rate of the actual temperature gradient within 1 second is 0.7 degrees Celsius per centimeter per second. Assuming the preset threshold is 0.5 degrees Celsius per centimeter per second, then 0.7 exceeds the preset threshold of 0.5, and then the gradient maintenance deviation is calculated by the formula , and 0.2 degrees Celsius per centimeter is obtained. The gradient maintenance deviation is used to correct the power output to suppress the gradient fluctuation. Conversely, if the change rate of the actual temperature gradient is less than 0.5, the gradient maintenance deviation is zero.

[0025] In an optional embodiment, calculating the gain weight of the proportional-integral control output based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of its adjacent temperature zones includes: When 1 < i < N, where N is the total number of temperature zones, the gain weight of the i-th temperature zone is calculated by the following formula ; ; wherein, is the attenuation coefficient, a gradient maintenance deviation for the i-th temperature zone, a gradient maintenance deviation for the i+1-th temperature zone; a gain weight for the 1st temperature zone is calculated by the following equation when i = 1 ; ; wherein, a decay coefficient, a gradient maintenance deviation for the 2nd temperature zone; a gain weight for the Nth temperature zone is calculated by the following equation when i = N, N is the total number of temperature zones ; ; wherein, a decay coefficient, a gradient maintenance deviation for the Nth temperature zone.

[0026] When a gradient maintenance deviation for a certain temperature zone is large, it indicates that the temperature zone is in an unstable state. The gain weight calculated for the temperature zone will be reduced, thus weakening the output of the proportional-integral controller and preventing the excessive reaction of the temperature deviation from intensifying system oscillation. On the contrary, when the gradient maintenance deviation is small or zero, the gain weight is close to 1, thus strengthening the output of the proportional-integral controller. For example, in a growth furnace containing five temperature zones, assume that the decay coefficient is 0.8. For the third temperature zone, its gain weight depends on both the gradient maintenance deviation between it and the second temperature zone and the gradient maintenance deviation between it and the fourth temperature zone. Assume that at a certain moment, the gradient maintenance deviation between the third and second temperature zones is calculated to be 0.2 degree Celsius per centimeter, and the gradient maintenance deviation between the third and fourth temperature zones is calculated to be -0.1 degree Celsius per centimeter, then the gain weight for the third temperature zone is approximately equal to 0.787. The gain weight less than 1 will properly suppress the proportional-integral control output of the third temperature zone. For the first temperature zone, its gain weight is only affected by the gradient maintenance deviation between it and the second temperature zone. If the gradient maintenance deviation is 0.05 degree Celsius per centimeter, then the gain weight for the first temperature zone is approximately equal to 0.961, indicating that the proportional-integral control of the first temperature zone is basically not affected by the gradient fluctuation at this moment.

[0027] S3, based on the influence factor matrix of the thermal correlation between the multiple temperature zones and the historical power output of other temperature zones, calculates a predictive thermal disturbance compensation for each temperature zone.

[0028] Specifically, an influence factor matrix H of dimensions is established, where N is the total number of temperature zones, and the matrix element This represents the steady-state influence coefficient of the unit power change in the j-th temperature zone on the temperature of the i-th temperature zone, with diagonal elements. This represents the steady-state influence coefficient of the i-th temperature zone itself; The predictive thermal disturbance compensation for the i-th temperature zone at time t is calculated using the following formula. ; ;in, For the j-th temperature zone Power output at any given moment For the j-th temperature zone Power output at any given moment The sampling period.

[0029] When the heating power of one temperature zone changes, the heat generated will inevitably be conducted to adjacent temperature zones, causing temperature disturbances. This embodiment measures the degree of mutual influence using a pre-calibrated influence factor matrix H and predicts the temperature impact that the recent power changes of all other temperature zones will have on the current temperature zone based on these changes. A predictive thermal disturbance compensation amount is then calculated. This is applied in advance to the current temperature zone to counteract external thermal disturbances. For example, in a growth furnace containing three temperature zones, for the second temperature zone, some elements of the influence factor matrix H, as measured experimentally, are: This equals 0.3 degrees Celsius per watt, meaning that increasing the power in the first temperature zone by 1 watt will ultimately raise the temperature in the second temperature zone by 0.3 degrees Celsius. Equal to 0.2 degrees Celsius per watt; the steady-state influence coefficient of the second temperature zone itself. The value is 1.5 degrees Celsius per watt. Assume that over the past two sampling periods, the power in the first temperature zone increased from 50 watts to 55 watts, while the power in the third temperature zone remained constant at 60 watts. The predictive thermal disturbance compensation for the second temperature zone is calculated. The power is -1 watt. The controller then reduces the power of the second temperature zone by 1 watt to offset the heat that will be conducted due to the increased power of the first temperature zone, thereby stabilizing the temperature of the second temperature zone.

[0030] S4. The temperature deviation of the temperature zone is processed by the proportional-integral controller, and the proportional-integral control output is adjusted by the gain weight to obtain the first control term; the predictive thermal disturbance compensation amount constitutes the second control term; the gradient feedforward correction amount constitutes the third control term, and the gradient feedforward correction amount is proportional to the gradient maintenance deviation of the temperature zone; the sum of the first control term, the second control term and the third control term is used as the power control amount of the temperature zone.

[0031] Specifically, the first control item is calculated using the following formula: ,in, is a first control term of the i-th temperature zone at time t, is a gain weight of the i-th temperature zone, is a proportional coefficient, is a temperature deviation of the i-th temperature zone at time t, is an integral coefficient, is an integral of the temperature deviation of the i-th temperature zone.

[0032] The gradient feedforward correction amount is calculated by the following formula: The gradient feedforward correction amount of the first temperature zone at time t is ; When , ; wherein, is a gradient feedforward correction amount of the i-th temperature zone at time t, is a feedforward coefficient, is a gradient maintenance deviation of the i-th temperature zone.

[0033] For example, assuming that the real-time temperature of the third temperature zone is 0.5 degrees Celsius lower than the target temperature, the integral of the temperature deviation of the third temperature zone is -2.0 degrees Celsius seconds, the gain weight of the third temperature zone is 0.787, the proportional and integral coefficients are 1.2 and 0.3 respectively, then the first control term is -0.944 watts. Assuming that the predictive thermal disturbance compensation amount is calculated as 0.8 watts, the gradient maintenance deviation is 0.2 degrees Celsius per centimeter, the feedforward coefficient is 0.5, then the gradient feedforward correction amount is 0.1 watts. Adding the first control term, the second control term and the third control term, the power control amount of the third temperature zone is -0.044 watts, then the power control amount is generated and sent to the corresponding heating actuator.

[0034] The implementation principle of the multi-region synergistic control method for the temperature field of the carbon nanotube CVD growth furnace is as follows: the application introduces a predictive thermal disturbance compensation mechanism based on an influence factor matrix, which can predict and offset thermal disturbances caused by the adjustment of adjacent temperature zones in advance, thereby effectively overcoming the problems of temperature overshoot and long-time oscillation in the traditional independent control mode, and significantly improving the establishment speed and stability of the target temperature profile. In addition, the application innovatively incorporates the temperature gradient between temperature zones into the control loop, calculates the gradient maintenance deviation in real time, and introduces a feedforward correction amount, so that the system can actively maintain the temperature gradient of the key process section constant, effectively avoiding the drastic fluctuation of the gradient caused by external disturbances. In addition, the application also includes a gain weight synergistic adjustment module, which dynamically adjusts the control output of each temperature zone according to the gradient state of the adjacent temperature zones, realizes the unity of local precise temperature control and overall temperature profile coordination, and ensures the global optimality of the control action.

[0035] The application provides a multi-region synergistic control system for the temperature field of a carbon nanotube CVD growth furnace, which comprises a memory and a processor, and the memory stores computer instructions.

[0036] Although the embodiments of the application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the application.

Claims

1. A method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace, characterized in that, Includes the following steps: The real-time temperatures of multiple temperature zones distributed along the axial direction of the growth furnace are obtained, and the temperature deviation of each temperature zone is calculated based on the preset target temperature distribution. Calculate the actual temperature gradient between each temperature zone and its adjacent temperature zones. If the rate of change of the actual temperature gradient exceeds a preset threshold, calculate the gradient maintenance deviation based on the difference between the actual temperature gradient and the target temperature gradient; otherwise, the gradient maintenance deviation is zero. Based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of its adjacent temperature zones, calculate the gain weight of the proportional-integral control output. Based on the influence factor matrix of thermal correlation between multiple temperature zones and the historical power output of other temperature zones, the predictive thermal disturbance compensation amount for each temperature zone is calculated. The temperature deviation of the temperature zone is processed by a proportional-integral controller, and the output of the proportional-integral control is adjusted by gain weight to obtain the first control term; the predictive thermal disturbance compensation amount constitutes the second control term; the gradient feedforward correction amount constitutes the third control term, which is proportional to the gradient maintenance deviation of the temperature zone; the sum of the first control term, the second control term and the third control term is used as the power control amount of the temperature zone.

2. The method for multi-region coordinated control of temperature field in a carbon nanotube CVD growth furnace according to claim 1, characterized in that, The actual temperature gradient is calculated using the following formula: ； Where i is greater than or equal to 2 and less than or equal to N, and N is the total number of temperature zones; Let be the actual temperature gradient of the i-th temperature zone at time t. Let be the distance between the center points of the i-th temperature zone and the (i-1)-th temperature zone. Let t be the real-time temperature of the i-th temperature zone; Let t be the real-time temperature of the (i-1)th temperature zone.

3. The method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 2, characterized in that, If the rate of change of the actual temperature gradient exceeds a preset threshold, the gradient maintenance deviation is calculated based on the difference between the actual temperature gradient and the target temperature gradient, including: The rate of change of the actual temperature gradient is calculated using the following formula: ； in, The actual temperature gradient of the i-th temperature zone during the sampling period Rate of change within; Let t be the actual temperature gradient of the i-th temperature zone; For a moment At that time, the actual temperature gradient of the i-th temperature zone; The sampling period; when When the gradient maintenance bias exceeds a preset threshold, the gradient maintenance bias is calculated using the following formula: ,in, To maintain the gradient deviation for the i-th temperature zone, Let be the actual temperature gradient of the i-th temperature zone at time t. The target temperature gradient.

4. The method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 3, characterized in that, The gain weight of the proportional-integral control output is calculated based on the gradient maintenance deviation of the temperature zone itself and the gradient maintenance deviation of its adjacent temperature zones, including: When 1 < i < N, where N is the total number of temperature zones, the gain weight of the i-th temperature zone is calculated by the following formula ; ;in, The attenuation coefficient is... To maintain the gradient deviation for the i-th temperature zone, The gradient maintenance deviation for the (i+1)th temperature zone; When i=1, the gain weight of the first temperature zone is calculated using the following formula. ; ;in, The attenuation coefficient is... To maintain the gradient deviation in the second temperature zone; When i=N, N is the total number of temperature zones. The gain weight of the Nth temperature zone is calculated using the following formula. ; ;in, The attenuation coefficient is... This is the gradient maintenance deviation for the Nth temperature zone.

5. The method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 4, characterized in that, The influence factor matrix based on the thermal correlation between multiple temperature zones and the historical power output of other temperature zones is used to calculate the predictive thermal disturbance compensation for each temperature zone, including: Establish A multidimensional influence factor matrix H, where N is the total number of temperature zones, and the matrix elements are... This represents the steady-state influence coefficient of the unit power change in the j-th temperature zone on the temperature of the i-th temperature zone, with diagonal elements. This represents the steady-state influence coefficient of the i-th temperature zone itself; The predictive thermal disturbance compensation for the i-th temperature zone at time t is calculated using the following formula. ; ;in, For the j-th temperature zone Power output at any given moment For the j-th temperature zone Power output at any given moment The sampling period.

6. The method for multi-region coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 5, characterized in that, The first control item is calculated using the following formula: ,in, Let t be the first control term of the i-th temperature zone. The gain weight for the i-th temperature region. This is the proportionality coefficient. Let be the temperature deviation of the i-th temperature zone at time t. The integral coefficient is... Let be the integral of the temperature deviation of the i-th temperature zone.

7. The method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 6, characterized in that, The gradient feedforward correction amount is calculated using the following formula: Gradient feedforward correction at time t in the first temperature zone ; when hour, ;in, Let be the gradient feedforward correction amount for the i-th temperature zone at time t. Forward coefficients, The gradient maintenance deviation for the i-th temperature zone.

8. The method for multi-regional coordinated control of the temperature field in a carbon nanotube CVD growth furnace according to claim 1, characterized in that, The method of acquiring the real-time temperature of multiple temperature zones distributed along the axial direction of the growth furnace includes: arranging temperature sensors inside each temperature zone of the growth furnace and collecting the real-time temperature of each temperature zone.

9. The method for multi-region coordinated control of temperature field in a carbon nanotube CVD growth furnace according to claim 1, characterized in that, The temperature deviation is the difference between the target temperature and the real-time temperature.

10. A multi-regional collaborative control system for the temperature field of a carbon nanotube CVD growth furnace, characterized in that, It includes a memory and a processor. The memory stores computer instructions. When the processor executes the computer instructions, it implements the multi-region collaborative control method of the temperature field of the carbon nanotube CVD growth furnace as described in any one of claims 1-9.

Images