An industrial oven temperature self-adaptive control method, device and instrument system based on load heat capacity estimation

Abstract

The application discloses an industrial oven temperature self-adaptive control method and device based on load heat capacity estimation and an instrument system, and belongs to the technical field of industrial process control. The method comprises the following steps: in a temperature rising trigger stage, a preset constant excitation power is output by a main controller, and the temperature inside an oven is collected to obtain a temperature rising slope; a virtual heat capacity characteristic value under a current working condition is estimated according to the constant excitation power and the temperature rising slope; the proportional coefficient and the integral time of a PID controller are adaptively mapped according to the relationship between the virtual heat capacity characteristic value and a reference heat capacity; the adjusted control parameters are used for closed-loop temperature control, and after the system enters a quasi-static heat balance state, a stable output power reference is locked based on the moving average trend of the output control quantity, and the integral term is limited to continue accumulation. The method can improve the matching of the PID control parameters and the actual load heat inertia of the industrial oven, help reduce the risk of light load overshoot or oscillation, and improve the response delay problem under a heavy load working condition.

Description

Technical Field

[0001] This invention relates to the field of industrial process control technology, and in particular to a temperature adaptive control method, device and instrument system based on load heat capacity estimation for industrial ovens under variable load conditions. Background Technology

[0002] Industrial ovens are widely used in industrial production processes that require heating, heat preservation, or curing. In actual use, the quantity, volume, or thermal inertia of the materials loaded inside the oven may vary from batch to batch. For temperature control systems, changes in loading conditions will alter the overall heat capacity and temperature rise response characteristics of the controlled object.

[0003] Existing industrial ovens typically employ PID control. PID control parameters are generally tuned under a typical load condition. When the oven load changes, the previously tuned fixed parameters may no longer match the characteristics of the current object. For example, under light load conditions, the controlled object has low thermal inertia; if the control action is too strong, overshoot or oscillation may occur when approaching the target temperature. Under heavy load conditions, the controlled object has high thermal inertia; if the original parameters are still used, it may exhibit slow heating response and prolonged time to reach the set temperature.

[0004] To address the aforementioned issues, engineering approaches include manually switching multiple sets of preset parameters or employing more complex online parameter optimization methods. However, manual switching relies on experience and is difficult to cover continuously changing load ranges; complex online optimization methods place high demands on computing resources, convergence processes, and operational stability, resulting in high implementation costs in real-time industrial control equipment.

[0005] Therefore, it is necessary to provide a temperature control method that is compatible with the temperature response characteristics of industrial ovens. Without introducing a complex optimization process, the current load thermal inertia can be estimated based on the response information during the heating stage, and the PID control parameters can be adjusted accordingly to improve the matching between the control parameters and the actual operating conditions. Summary of the Invention

[0006] 1. Technical problems to be solved This invention aims to solve the problem that when the fixed PID control parameters of an industrial oven are mismatched with the current load heat capacity under different loading or material thermal inertia conditions, overshoot or oscillation may occur under light load conditions, and slow response may occur under heavy load conditions.

[0007] 2. Technical Solution To achieve the above objectives, the present invention provides an adaptive temperature control method for an industrial oven based on load heat capacity estimation, comprising the following steps: During the heating triggering phase, the main controller outputs a preset constant excitation power. The temperature acquisition module collects the internal temperature of the oven in real time and obtains the heating slope based on the temperature change over time. Since different load thermal inertia will exhibit different heating responses under the same or comparable constant power excitation, the heating slope can be used as input for subsequent load heat capacity estimation.

[0008] The heat capacity estimation module estimates the virtual heat capacity characteristic value under the current operating conditions based on the preset constant excitation power and heating slope. This virtual heat capacity characteristic value is not a direct measurement of the material's actual heat capacity, but rather a characterization of the overall thermal inertia characteristics formed by the oven, the material, and their heat exchange states.

[0009] The parameter mapping module adaptively maps the proportional gain and integral time of the PID controller based on the relationship between the virtual heat capacity characteristic value and the reference heat capacity. This mapping allows the controller parameters to adjust according to changes in load thermal inertia, thereby reducing the risk of mismatch between fixed parameters under varying load conditions.

[0010] The main controller inputs the adjusted proportional coefficient and integral time into the PID calculation, generates a control output based on the deviation between the current temperature and the target temperature, and drives the heating actuator through the power drive module.

[0011] Furthermore, after the system completes adaptive parameter adjustment and enters a quasi-static thermal equilibrium state, the steady-state output power reference is locked based on the moving average trend of the control output within the sliding time window, and the accumulation of the integral term is limited. This process enables the controller to maintain thermal equilibrium with the fixed output power reference in the steady-state phase, while the proportional and derivative terms correct for instantaneous disturbances, which helps to reduce the slow temperature drift caused by the continuous accumulation of the integral term.

[0012] To address the aforementioned problems, this invention also provides an adaptive temperature control device for an industrial oven based on load heat capacity estimation. The device includes a temperature acquisition module, a heat capacity estimation module, a parameter mapping module, a main controller module, and a power drive module. The temperature acquisition module provides temperature data to the heat capacity estimation module and the main controller module; the heat capacity estimation module outputs a virtual heat capacity characteristic value based on a constant excitation power and a heating slope; the parameter mapping module outputs adaptive PID parameters based on the virtual heat capacity characteristic value; the main controller module generates a control output based on the adaptive PID parameters; and the power drive module drives the heating actuator based on the control output.

[0013] This invention also provides an industrial oven temperature adaptive control instrument system based on load heat capacity estimation. The instrument system includes a temperature sensor interface, a power output interface, a human-machine interface unit, a storage unit, and the temperature adaptive control device. The temperature sensor interface is used to receive temperature detection signals from inside the oven; the human-machine interface unit is used to set the target temperature, preset constant excitation power, reference heat capacity, and PID reference parameters; the storage unit is used to store control parameters, heat capacity estimation parameters, and operating data; the power output interface is used to output control signals to the heating actuator or power driver according to the control output quantity.

[0014] To address the aforementioned problems, the present invention also provides a storage medium storing a computer program, wherein the computer program is configured to execute the above-described method at runtime.

[0015] To address the aforementioned problems, the present invention also provides an electronic device, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the method described in any of the preceding claims.

[0016] 3. Beneficial effects Compared with the fixed-parameter PID control method, the present invention has at least the following advantages: This invention applies a preset constant excitation power during the heating triggering stage and uses the heating slope to estimate the virtual heat capacity characteristic value, enabling the control system to obtain the thermal inertia characterization quantity related to the current loading state, thereby providing a basis for PID parameter adjustment.

[0017] This invention adjusts the proportional coefficient and integral time based on the relationship between the virtual heat capacity characteristic value and the reference heat capacity, so that the control parameters can change with the change of load thermal inertia, which helps to improve the problems of overly strong control action under light load conditions and slow response under heavy load conditions.

[0018] This invention locks the steady-state output power reference after the system enters a quasi-static thermal equilibrium state and limits the continued accumulation of integral terms, which helps to reduce the risk of slow temperature drift caused by the accumulation of integral terms in the steady-state stage.

[0019] The heat capacity estimation and parameter mapping process used in this invention is directly related to the heating response of industrial ovens. The control logic is clear and easy to implement in industrial temperature control devices and instrument systems. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the adaptive temperature control method for industrial ovens based on load heat capacity estimation proposed in this invention. Figure 2This is a functional block diagram of the industrial oven temperature adaptive control device based on load heat capacity estimation proposed in this invention. Figure 3 This is a schematic diagram of the electronic device for implementing the adaptive temperature control method for industrial ovens based on load heat capacity estimation proposed in this invention. Detailed Implementation

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0022] See Figure 1 This invention provides an adaptive temperature control method for industrial ovens based on load heat capacity estimation. Before executing this method, the control system loads process reference parameters from non-volatile memory, including: no-load reference proportional coefficient. No-load reference integration time Unloaded reference heat capacity Excitation power (For example, set to 60% of rated power), proportional coefficient safety threshold and thermal efficiency compensation coefficient The method specifically includes the following steps: S1: Output a preset constant excitation power and obtain the heating slope.

[0023] During the temperature rise triggering phase, the main controller uses the power drive module to cause the heating actuator to operate at a preset constant excitation power. The temperature acquisition module collects the internal temperature of the oven in real time and provides temperature data to the main controller and the heat capacity estimation module.

[0024] During this phase, the control system obtains the temperature rise slope based on the temperature change over time. Because the overall thermal inertia of the oven varies under different loading conditions, its temperature rise slope will also differ under the same preset constant excitation power. Therefore, the temperature rise slope can reflect the temperature rise response characteristics under the current load condition.

[0025] In practice, the temperature change trend can be obtained within a preset temperature rise measurement range to reduce the impact of instantaneous temperature fluctuations on the extraction of the temperature rise slope. This process does not change the basic idea of ​​characterizing the thermal inertia of the current load through the temperature rise response.

[0026] S2: Estimate the virtual heat capacity characteristic value.

[0027] The heat capacity estimation module receives the temperature rise slope. And combined with a preset constant excitation power Estimate the virtual heat capacity characteristic value under current operating conditions The virtual heat capacity characteristic value It can be determined using the following formula: in, This is the preset oven thermal efficiency compensation coefficient, used to compensate for the impact of environmental heat dissipation and other factors on the estimation results.

[0028] The virtual heat capacity characteristic value in this embodiment Used to characterize the overall thermal inertia of the oven under current loading conditions. If Relative to reference heat capacity A larger value indicates that the current load has strong thermal inertia; if Relative to reference heat capacity A smaller value indicates that the current load thermal inertia is relatively weak.

[0029] S3: Perform adaptive mapping of PID parameters and implement safety limiting.

[0030] The parameter mapping module is based on the virtual heat capacity characteristic value. Compared with reference heat capacity The relationship between them generates an adaptive scaling factor. and adaptive integral time The mapping relationship can be represented as follows: in, As the benchmark scaling factor, As the baseline integration time, The reference heat capacity is used.

[0031] Through the above mapping, as the current virtual heat capacity characteristic value increases, the adaptive proportional coefficient also increases, and the adaptive integral time also increases accordingly. The former is used to enhance the control effect under heavy load conditions, while the latter is used to avoid excessive integral action leading to a decrease in stability. In this way, the control parameters can establish a correspondence with the current load thermal inertia, reducing the mismatch of fixed parameters under variable load conditions.

[0032] To avoid the proportional coefficient being too large and affecting control stability, the parameter mapping module can use the calculated adaptive proportional coefficient. Compare with a preset proportional coefficient safety threshold. When When this safety threshold is exceeded, The limit is set within this safety threshold. This safety limit applies to the control parameter output and does not alter the estimated virtual heat capacity characteristic value.

[0033] S4: Execute closed-loop PID control and solidify the steady-state output power reference.

[0034] The main controller module receives the adaptive proportional coefficient. and adaptive integral time It then performs PID calculations based on the deviation between the current temperature and the target temperature to generate the control output. The power drive module receives control output signals. Then, the heating actuator is driven to work to regulate the internal temperature of the oven.

[0035] After the system completes the adaptive parameter update and the temperature enters the preset deviation range of the target temperature, the main controller further monitors the control output. The changing trend. Specifically, the control output can be calculated. The system calculates the moving average value within the sliding time window and determines whether the trend of this moving average value meets the preset stability conditions. If it does, the system is determined to have entered a quasi-static thermal equilibrium state.

[0036] Once the system reaches quasi-static thermal equilibrium, the main controller locks the current moving average value as the steady-state output power reference. Thereafter, the controller uses this steady-state output power reference as the basis for maintaining thermal equilibrium, limiting the accumulation of the integral term and correcting for instantaneous temperature disturbances using the proportional and derivative terms. This process reduces the risk of slow temperature drift caused by the continuous accumulation of the integral term after the system has reached a new thermal equilibrium.

[0037] See Figure 2 This embodiment provides an industrial oven temperature adaptive control device based on load heat capacity estimation, whose functional modules specifically include: Temperature acquisition module 201: used to acquire the internal temperature of the oven and send the temperature data to heat capacity estimation module 202 and main controller module 204; Heat capacity estimation module 202: Used to receive temperature data during the heating triggering phase and calculate virtual heat capacity characteristic values ​​based on preset constant excitation power and heating slope. This virtual heat capacity characteristic value is used to characterize the overall thermal inertia formed by the oven and the loaded materials under the current operating conditions; Parameter mapping module 203: Used to receive virtual heat capacity characteristic values and according to Compared with reference heat capacity Generate adaptive scaling coefficients based on the relationship between them and adaptive integral time The parameter mapping module 203 can also perform safety limiting on the adaptive scaling factor; Main controller module 204: Receives temperature data, adaptive proportional coefficient, and adaptive integral time; performs PID calculations based on the deviation between the current temperature and the target temperature; and generates the control output. The main controller module 204 is also used to lock the steady-state output power reference based on the moving average trend of the control output after the system enters a quasi-static thermal equilibrium state, and to limit the continued accumulation of the integral term; Power drive module 205: Used to receive control output from main controller module 204. The control output is used to drive the heating actuator to change the heating power of the oven.

[0038] This embodiment also provides an industrial oven temperature adaptive control instrument system based on load heat capacity estimation. The instrument system includes a temperature sensor interface, a power output interface, a human-machine interface unit, a storage unit, and the aforementioned temperature adaptive control device.

[0039] The system includes a temperature sensor interface for receiving temperature detection signals from inside the oven and providing these signals to the temperature acquisition module. A power output interface for outputting control signals to the heating actuator or power driver based on the control output generated by the main controller module. A human-machine interface unit allows operators to set at least one parameter among the following: target temperature, preset constant excitation power, reference heat capacity, reference proportional coefficient, reference integral time, and proportional coefficient safety threshold. It also displays at least one piece of information: current temperature, target temperature, control output, virtual heat capacity characteristic value, and operating status. A storage unit stores at least one type of data, including process reference parameters, heat capacity estimation parameters, adaptive PID parameters, steady-state output power reference, and operating data.

[0040] With the above settings, the instrument system can complete temperature acquisition, load heat capacity estimation, PID parameter adaptive adjustment, control output, and display and storage of operating parameters during the operation of the industrial oven, thereby facilitating the application of the temperature adaptive control method to industrial temperature control instruments.

[0041] See Figure 3 This embodiment also provides an electronic device architecture for implementing the above-described temperature adaptive control method. The electronic device includes a processor and a memory connected via a system bus. A non-volatile storage medium can store an operating system and a computer program. The computer program includes program instructions that, when executed, cause the processor to perform any industrial oven adaptive temperature control method based on load heat capacity estimation.

[0042] The processor provides computing and control capabilities, supporting the operation of the entire computer device.

[0043] The internal memory provides an environment for the execution of computer programs in non-volatile storage media. When the computer program is executed by the processor, it enables the processor to execute any adaptive temperature control method for industrial ovens based on load heat capacity estimation.

[0044] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific electronic devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

Claims

1. A method for adaptive temperature control of an industrial oven based on load heat capacity estimation, characterized in that, Includes the following steps: S1: During the temperature rise triggering phase, the main controller outputs a preset constant excitation power. The temperature acquisition module collects the internal temperature of the oven in real time. The heating slope is obtained based on the change in the internal temperature of the oven over time. ; S2: The heat capacity estimation module estimates the heat capacity based on the preset constant excitation power. and the aforementioned heating slope Estimate the virtual heat capacity characteristic value under the current operating conditions. The virtual heat capacity characteristic value is used to characterize the overall thermal inertia of the oven after it is loaded with materials; S3: The parameter mapping module maps the virtual heat capacity characteristic value. The relationship with the reference heat capacity is used to generate the adaptive proportional coefficient of the PID controller. and adaptive integral time This allows the control parameters of the PID controller to be adjusted according to changes in the thermal inertia of the current load; S4: The main controller substitutes the adaptive proportional coefficient and the adaptive integral time into the PID calculation, and calculates the temperature based on the deviation between the current temperature and the target temperature. Generate control output And drive the heating actuator through the power drive module; After the system enters a quasi-static thermal equilibrium state, the steady-state output power reference is locked based on the moving average trend of the control output, and the integral term is limited from accumulating further.

2. The method according to claim 1, characterized in that, In step S2, the virtual heat capacity characteristic value The calculation formula is: in, This is the preset oven thermal efficiency compensation coefficient, used to correct estimation errors caused by environmental heat dissipation.

3. The method according to claim 1, characterized in that, In step S3, the mapping relationship between the adaptive scaling factor and the adaptive integral time is as follows: in, and These represent the baseline proportional gain and baseline integral time of the system under no-load conditions, respectively. This is the baseline heat capacity value under no-load conditions.

4. The method according to claim 3, characterized in that, Step S3 further includes a safety limiting step: comparing the adaptive scaling factor with a preset scaling factor safety threshold, and when the adaptive scaling factor exceeds the preset scaling factor safety threshold, limiting the adaptive scaling factor to within the preset scaling factor safety threshold.

5. The method according to claim 1, characterized in that, In step S4, the quasi-static thermal equilibrium state is determined as follows: when the temperature enters a preset deviation range of the target temperature, the moving average value of the control output quantity within a sliding time window is calculated; if the trend of the moving average value meets a preset stability condition, the system is determined to have entered a quasi-static thermal equilibrium state, and the current moving average value is used as the steady-state output power reference. After locking the steady-state output power reference, the main controller uses the steady-state output power reference as the output reference for maintaining thermal equilibrium, and limits the further accumulation of the integral term, while the proportional and derivative terms correct for instantaneous temperature disturbances.

6. An adaptive temperature control device for an industrial oven based on load heat capacity estimation, characterized in that, The device includes: The temperature acquisition module collects the internal temperature of the oven and provides temperature data to the heat capacity estimation module and the main controller module. The heat capacity estimation module receives the temperature data and, in conjunction with the preset constant excitation power and heating slope of the heating triggering stage, outputs the virtual heat capacity characteristic value under the current operating conditions. The parameter mapping module receives the virtual heat capacity characteristic value and outputs the adaptive proportional coefficient and adaptive integral time of the PID controller based on the relationship between the virtual heat capacity characteristic value and the reference heat capacity. The main controller module generates a control output based on the adaptive proportional coefficient, the adaptive integral time, and the deviation between the current temperature and the target temperature, and performs steady-state output power reference solidification after the system enters a quasi-static thermal equilibrium state. A power drive module receives the control output and drives the heating actuator according to the control output.

7. An adaptive temperature control instrument system for an industrial oven based on load heat capacity estimation, characterized in that, It includes a temperature sensor interface, a power output interface, a human-machine interaction unit, a storage unit, and a temperature adaptive control device as described in claim 6; The temperature sensor interface is used to receive the temperature detection signal inside the oven and provide the temperature detection signal to the temperature adaptive control device. The human-computer interaction unit is used to set at least one parameter among the following: target temperature, preset constant excitation power, reference heat capacity, reference proportional coefficient, reference integral time, and proportional coefficient safety threshold. The storage unit is used to store at least one of the following data: target temperature, preset constant excitation power, reference heat capacity, reference proportional coefficient, reference integration time, proportional coefficient safety threshold, virtual heat capacity characteristic value, and steady-state output power reference. The power output interface is used to output control signals to the heating actuator or power driver according to the control output generated by the temperature adaptive control device.

8. A storage medium, characterized in that, The storage medium stores a computer program, wherein the computer program is configured to execute the method of any one of claims 1-4 when it is run.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the method of any one of claims 1-4.

Images