Array electric tracing band heating control method and system

Abstract

The invention relates to an array electric tracing band heating control method and system, and the method comprises the steps: an array construction and control circuit construction step: arranging and fixing a heating unit array on a supporting body, and configuring one-to-one voltage regulation and control links; a temperature value obtaining step: calculating resistance by collecting voltage and current of the heating unit, and obtaining the real-time temperature of the heating unit in combination with the resistance-temperature reference curve; a compensation voltage calculation step: establishing a model based on the bearing body partition temperature difference, the heating unit temperature and the multi-dimensional influence parameters, and calculating a compensation voltage; a temperature regulation and control step: superposing the compensation voltage and the real-time voltage to regulate the heating power so as to realize the precise temperature control of the bearing body partition; the system comprises a main control module, a power drive and control module, a sensor module and a power supply module, and all the modules cooperate to complete control logic. According to the invention, the bearing body partition temperature control precision and the reliability of the system are improved, and the system adapts to various bearing body forms.

Description

A heating control method and system for arrayed electric heating tape Technical Field

[0001] This invention relates to the field of temperature control and regulation system technology, specifically to a heating control method and system for arrayed electric heating tapes. Background Technology

[0002] Currently, in many electric heat tracing applications, such as pipeline antifreeze and tank insulation, control systems based on mechanical temperature controllers or contactors are still widely used. This system senses the temperature of the object being heated or the environment through one or more mechanical temperature sensors. When the temperature falls below a set lower limit, the mechanical contacts within the temperature controller close, connecting the circuit and initiating heating with the electric heat tracing tape. When the temperature reaches the set upper limit, the contacts mechanically open, stopping heating. This technology has some drawbacks and problems in practical applications. Mechanical temperature controllers suffer from low control accuracy and significant energy waste; control systems based on mechanical temperature controllers or contactors have limited control functions and cannot achieve intelligent management; the systems typically operate in isolation, lacking remote communication, fault alarm functions, and centralized monitoring and data recording capabilities; furthermore, mechanical contacts are prone to generating electrical sparks, posing a safety hazard.

[0003] Furthermore, a self-regulating heating cable, also known as an electric heating cable, is proposed, which utilizes its ability to automatically adjust its heating power according to changes in ambient temperature. Its core component is a PTC polymer material as the heating element. When the ambient temperature is low, the microstructure of the PTC material shrinks, forming more conductive paths, reducing resistance and increasing heating power. When the ambient temperature rises, the PTC material expands, reducing conductive paths, increasing resistance, and automatically decreasing heating power.

[0004] However, the electric heating tape mentioned above still has problems in application. Because the adjustment function of the electric heating tape is local and passive, it cannot receive instructions from the central control system, nor can it achieve global and precise temperature control according to the needs of the entire process, such as different areas of the pipe section needing to meet different temperature requirements. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide an arrayed electric heating cable heating control method and system, in order to solve the problems of low temperature control accuracy, disconnection of carrier temperature control, poor adaptability to working conditions, and insufficient reliability of the control system in the current electric heating cable heating control technology.

[0006] This invention provides a heating control method for arrayed electric heating tapes, characterized in that the control method specifically includes:

[0007] The control circuit establishment step divides the carrier into several heating zones, and sets up multiple independent heating units in each heating zone. Each heating unit is equipped with a power regulation unit, forming a one-to-one control link. This step achieves zoned arrangement and distributed control of the carrier, thus avoiding the inability to locally regulate traditional whole-section heat tracing. The temperature value acquisition step acquires the real-time voltage and current of each heating unit to obtain its real-time resistance value. Using the real-time resistance value as an index, a matching real-time heating temperature value is searched in a preset resistance-temperature baseline. The real-time heating temperature value represents the estimated self-temperature of the heating unit at the current moment. This step obtains the real-time heating temperature value of the heating unit by establishing a resistance-temperature baseline, eliminating the need for temperature sensors and reducing... The process involves low cost and direct acquisition of the heating unit's body temperature. A compensation calculation step involves acquiring the measured temperature value of each heating zone and comparing it with the preset temperature value of each zone to obtain the temperature deviation. This temperature deviation is then substituted into a PID algorithm to obtain the corresponding power control amount for each heating zone. This step uses a mature PID control algorithm, taking the temperature deviation between the measured temperature and the preset temperature as input to obtain the total power control amount for that heating zone. A temperature control step involves allocating the power control amount for each heating zone according to a distribution strategy to obtain the corresponding compensation power for each heating unit within that zone, and inputting this power to the corresponding heating unit. This process is repeated for each heating unit, following the temperature value acquisition step, compensation calculation step, and temperature control step, until the temperature deviation is less than a preset temperature difference threshold, making the measured temperature value of the zone close to the corresponding preset temperature value.

[0008] This step distributes the total power control amount of the region to each heating unit according to the allocation strategy, making the control more precise, and repeats the process until the temperature deviation is less than the threshold.

[0009] Furthermore, the allocation strategy specifically involves: obtaining the relative position of each heating unit in the target heating area relative to the target heating area and obtaining the relative position of the target heating area relative to the carrier; obtaining the real-time heating temperature value of each heating unit in the target heating area, as well as the measured regional temperature value of the target heating area and the measured regional temperature value of the adjacent heating areas; calculating the power control allocation weight value corresponding to each heating unit in the target heating area based on the relative position of each heating unit in the target heating area, the real-time heating temperature value, and the measured regional temperature value of the adjacent heating areas; and obtaining the compensation power of each heating unit based on the power control allocation weight value.

[0010] The allocation strategy comprehensively considers the relative position of the heating unit within the region when calculating the weight of each heating unit to compensate for the difference between being located at the edge or the center. The heating unit heats the temperature value in real time to achieve on-demand compensation. It also considers the thermal coupling between the temperatures of adjacent heating areas, making the control more realistic and more accurate.

[0011] Furthermore, the temperature value acquisition step is configured with a heating unit self-temperature correction sub-strategy. After the real-time heating temperature value is found from the resistance-temperature baseline, the heating unit self-temperature correction sub-strategy is executed. Specifically, the cumulative power-on time of each heating unit is recorded, and the duration aging correction amount is calculated based on the cumulative power-on time; the real-time heating temperature value corresponding to the heating unit is obtained according to the resistance-temperature baseline, and the temperature difference between the heating unit and the adjacent heating unit is calculated based on the real-time heating temperature values ​​of the heating unit and the corresponding adjacent heating units; the thermal coupling correction amount is calculated using a preset thermal coupling coefficient; the temperature value obtained by summing the real-time heating temperature value of the heating unit with the duration aging correction amount and the thermal coupling correction amount is used as the corrected real-time heating temperature value of the heating unit.

[0012] The correction sub-strategy aims to obtain a more accurate real-time heating temperature value for the heating unit. It requires compensation for aging caused by long-term use and correction for the thermal coupling effect between adjacent heating units, so as to improve the accuracy of the real-time heating temperature value and provide a reliable basis for weight allocation.

[0013] Furthermore, the adjacent heating units include adjacent heating units within the same heating area of ​​the heating unit, and cross-regional adjacent heating units in other heating areas that are adjacent to the heating area of ​​the heating unit.

[0014] When considering adjacent heating units, it is necessary to consider not only heating units within the same heating area, but also heating units across different areas, so as to fully cover all adjacent units that have a thermal impact on the target heating unit.

[0015] Furthermore, the specific steps for establishing the resistance-temperature baseline are as follows: In a simulated constant temperature chamber, by adjusting the power of the input heating unit and the temperature of the constant temperature chamber, and keeping the current operating conditions unchanged and allowing it to remain stationary for a period of time, temperature and resistance values ​​are collected. When it is determined that both the temperature change rate and the resistance change rate of the heating unit are lower than the threshold, the current moment is considered a stable state, and the resistance and temperature values ​​of the heating unit at this time are recorded. The recorded resistance, temperature, and ambient temperature values ​​are combined into a set of data, and multiple sets of data form a dataset. By establishing a fitting relationship between the datasets, the resistance-temperature baseline of the heating unit is obtained.

[0016] Through constant temperature chamber experiments, an accurate, reliable resistance-temperature mapping relationship with environmental temperature compensation was established.

[0017] Furthermore, in the repeated temperature value acquisition step, after inputting compensation power to each heating unit in the heating area, the power output remains unchanged and the area temperature value of the heating area is collected after a preset stable duration. The area temperature value that meets the stability condition is determined as the measured temperature value of the area. The stability condition is specifically the temperature change rate obtained by the ratio of the temperature difference between the current area temperature value and the area temperature value at the previous moment to time, and the temperature change rate is lower than the change threshold.

[0018] After each application of compensation power to the heating unit, a preset stabilization time is waited for, and stability is determined by the temperature change rate being lower than a threshold. Then, the regional temperature is collected as feedback to ensure that the input temperature difference is a stable temperature difference and to avoid frequent adjustments caused by transient temperature fluctuations.

[0019] Furthermore, the temperature control step includes a fault judgment strategy, specifically comprising: accumulating the number of times each heating zone performs continuous compensation steps and comparing it with a set threshold number; if the number exceeds the threshold number and the temperature deviation is still greater than the temperature difference threshold, then it is determined that the heating unit in that heating zone is abnormal and a fault alarm is triggered; obtaining the measured temperature of the heating zone after two adjacent compensation adjustments, calculating the absolute value of the temperature change between the two adjacent measured temperatures, and comparing it with a set change threshold; if the change is less than the change threshold and the temperature deviation is still greater than the temperature difference threshold, then it is determined that the heating unit in that heating zone is abnormal and a fault alarm is triggered.

[0020] If the number of consecutive compensations is too high and the temperature still does not meet the standard, or if the temperature change is very small after two consecutive compensations but the stability still does not meet the standard, it indicates that there is an abnormality in the heating unit, thus enabling timely detection of abnormalities in the heating unit during the closed-loop regulation process.

[0021] Furthermore, the temperature control step also includes a compensation power adjustment strategy, specifically: the compensation power of each heating unit is summed with the current actual input power to obtain the total input power; the total input power is compared with the rated maximum power; if it exceeds the rated maximum power, the rated maximum power is set as the input power of the heating unit; the total input power is compared with the rated minimum power; if it is lower than the rated minimum power, the rated minimum power is set as the input power of the heating unit.

[0022] The compensation power adjustment strategy ensures the upper and lower limits of the input power of each heating unit, avoiding damage to the heating unit due to excessive power or waste of energy due to insufficient power.

[0023] This invention also provides a system applicable to the above-mentioned arrayed electric heating cable heating control method. The system includes: a main control module, storing the control link addresses of all heating units and the resistance-temperature reference line, used for running compensation calculation steps and executing control logic tasks; a power drive and control module, including a power regulation unit corresponding to each heating unit, the power regulation unit being used to receive control signals from the main control module to adjust the conduction of the power regulation unit, the power regulation unit being used to regulate the power input to the heating unit; a temperature acquisition module, used to acquire the measured temperature values ​​of each heating area; a power supply module, used to provide power to each module; a wireless communication module, used for data interaction between the main control module and the remote monitoring platform; a human-machine interaction module, used to display on-site working parameter information and allow local parameter setting and operation; and a remote monitoring platform, used to display the real-time operating parameters of each heating unit and to be responsible for alarm management and remote control.

[0024] Furthermore, the heating unit is an electric heating tape.

[0025] Technical effects of the present invention: The present invention achieves differentiated and precise temperature control of multiple regions of the carrier by dividing the carrier into sections and using an array of multiple heating units for independent control. By obtaining the temperature difference of each heating area and relying on regional PID adjustment and fine power distribution, the present invention significantly improves temperature uniformity and control accuracy, and solves the problems of large local temperature differences and unsatisfactory carrier temperature control caused by traditional overall control.

[0026] This invention achieves more accurate real-time heating temperature values ​​of the heating unit by setting a temperature correction sub-strategy; and limits the input power range by designing a fault judgment strategy and an input power adjustment strategy, thereby avoiding system risks caused by compensation failure or heating unit failure and improving long-term operational reliability. Attached Figure Description

[0027] Figure 1 is a schematic flowchart of a heating control method for an arrayed electric heating cable according to the present invention.

[0028] Figure 2 is a block diagram of the control circuit of a single electric heating cable in an arrayed electric heating cable control system of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that when a component is described as "fixed to" another component, it can be directly on the other component or may have a component in between. When a component is considered "connected to" another component, it can be directly connected to the other component or may have a component in between. When a component is considered "set on" another component, it can be directly set on the other component or may have a component in between. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] This invention proposes an arrayed electric heating cable heating control system. The system is installed in an intelligent control box and includes: a main control module, which stores the control link addresses of all heating units and the resistance-temperature baseline of each heating unit. It can employ an STM32F103 series ARM Cortex-M3 core microcontroller U3, containing a computational model for calculating power values ​​based on temperature difference data, PID controller proportional parameters, PID controller integral parameters, and PID controller derivative parameters. This model is responsible for running compensation calculation steps to calculate the power regulation amount for each heating zone, processing data, managing communication, and executing control logic tasks. A power drive and control module includes a power regulation unit corresponding to each heating unit. Each power regulation unit receives control signals from the main control module to adjust its conduction, and each power regulation unit is used to regulate the power input to its corresponding heating unit.

[0033] In one embodiment of the present invention, the power regulation unit adopts a zero-crossing optocoupler-type bidirectional thyristor, which has a built-in zero-crossing detection function to reduce electromagnetic interference when the thyristor is turned on. The input terminal of the optocoupler-type bidirectional thyristor is connected to the PWM_P output pin of the main control module U3 through a current-limiting resistor. When the main control module U3 outputs a trigger signal, the optocoupler-type bidirectional thyristor conducts, which in turn triggers the high-power thyristor to conduct near the zero-crossing point of the AC current. The effective voltage and power input to the heating unit are adjusted by changing the conduction angle of each half-wave cycle. The temperature acquisition module includes temperature sensors that collect the measured temperature values ​​of each heating zone. PT100 platinum resistance temperature sensors can be used as probes, installed on each zone of the carrier. A high-precision ADC digital converter chip and its peripheral circuitry are configured to convert the resistance signal of the PT100 platinum resistance temperature sensor into a high-precision digital temperature value, which is then transmitted to the main control module U3. The power supply module uses a switching power supply with a 220V AC input and a +12V DC output. The +12V DC is converted to +5V DC via a DC-DC circuit to power the communication module. The +5V DC is then converted to +3.3V via an LD1117-3.3 LDO regulator chip to power the main control module U3, the temperature acquisition module, and other core circuits. The wireless communication module uses LoRa+4G. The CAT.1 dual-mode module consists of two parts: the LoRa portion uses EBITE's E22-400T30D module, connected to the main control module U3 via UART, for communication with the LoRa gateway within the factory area to achieve low-power data aggregation; the 4G portion uses Yike Communication's NC_ML307R module, connected to the main control module U3 via UART, serving as the primary channel for directly uploading data to the cloud platform; and the human-machine interface module, specifically an OLED display mounted on the enclosure, communicates with the main control module U3 via I2C for displaying on-site operating parameters and information. Human-machine interaction can be achieved via Bluetooth using a handheld device, allowing for local parameter setting and operation. The handheld device is a portable device for controlling industrial equipment, typically interacting with operators through buttons, knobs, or touchscreens, or establishing a wireless connection with the controlled equipment via Bluetooth for remote control. The remote monitoring platform adopts a B / S architecture, deployed on a cloud server, with the backend developed using languages ​​such as Java or Python, the database using MySQL, and the frontend using the Vue.js framework. This remote monitoring platform receives data from a 4G module and a LoRa gateway via the MQTT protocol.

[0034] In one embodiment of the present invention, the heating unit adopts electric heating tape. In practical applications, the area is first divided according to the temperature control requirements of the carrier, and the boundaries between adjacent heating areas must be clear, without overlap or omission, and the entire surface to be heated must be covered. Each heating area has independent temperature control, independent power output, and independent temperature acquisition. Multiple electric heating tapes are arranged in each heating area, and these electric heating tapes need to be standardized. Specifically, the electric heating tapes in all heating areas have the same length, shape, size, nominal power, and resistance value. In addition, the electric heating tapes in all heating areas are laid out in the same way, and the laying spacing between electric heating tapes in the same area and between electric heating tapes across areas are consistent, thereby ensuring that the control algorithm, the baseline, and the weight allocation of the heating unit are universal for all heating areas. It is also necessary to configure an independent control link for each electric heating tape in each heating area to realize independent voltage sampling, current sampling, and power adjustment output for each heating unit.

[0035] In one embodiment of the present invention, multiple heating areas are divided on the carrier, and multiple heating units are installed in each heating area. During the installation process, the position of each heating area relative to the carrier, the adjacency relationship between each heating area, the position of each heating unit relative to its heating area, and the adjacency relationship between each heating unit are recorded and stored in the control system. Specifically, after the heating area division of the carrier and the installation and deployment of each heating unit are completed, during the system installation and configuration stage, the position information of each heating area relative to the carrier, the adjacency relationship between each heating area, the position information of each heating unit relative to its heating area (including center position, internal position, and edge position), and the adjacency relationship between each heating unit and other heating units (including adjacency within the same area and adjacency across areas) are recorded and stored in the control system. It is also necessary to store the spacing between adjacent heating units within the same area and the spacing between adjacent heating units across areas in the control system.

[0036] Because the position of each heating zone and each heating unit remains unchanged after installation, there is no need to detect or identify the position again during subsequent temperature control. The stored position information can be directly called to determine the relative position and adjacent relationship of each heating unit.

[0037] Based on the above-mentioned arrayed electric heating cable heating control system, this invention also proposes a heating control method, including a control circuit establishment step, a temperature acquisition step, a compensation calculation step, and a temperature regulation step, to achieve precise temperature control, as shown in Figure 1. Specifically, in the control circuit establishment step, the carrier is divided into several heating areas, and multiple independent heating units are set in each heating area, with each heating unit configured with a power regulation unit to form a one-to-one control link. This step is the foundational step in the arrayed electric heating cable heating control method. Dividing the carrier into multiple heating areas is to achieve distributed and refined temperature control, overcoming the technical deficiency of traditional whole-section heating that cannot be locally adjusted. In this invention, the heating zone refers to several independent and clearly defined temperature control units formed by dividing the entire surface to be heated of the carrier according to the temperature control requirements, structural form, heat dissipation conditions, and actual application conditions. Each heating zone has independent temperature acquisition and power regulation capabilities. Each heating zone is equipped with heating units, which are the smallest independent heating elements constituting the arrayed heating structure. In this invention, the heating units use electric heating tapes, specifically self-regulating electric heating products using PTC polymer material as the heating element, possessing the basic characteristic of adjusting its resistance value according to changes in ambient temperature. For example, an industrial pipeline requires full insulation and antifreeze protection, with a total length of 100 meters. The specific details depend on the pipeline's on-site installation... The environmental heat dissipation conditions divide the tank into 10 heating zones, each 10 meters long. The target insulation temperature for each zone is 5 degrees Celsius. The fixed supports of the pipes serve as natural boundaries, ensuring clear and relatively independent boundaries. For circular storage tanks, the tank can be divided using a combination of circumferential and radial divisions. Taking a vertical liquid storage tank with a diameter of 5 meters and a height of 8 meters as an example, the tank is divided into circumferential zones every 90 degrees and radial zones every 2 meters, forming 16 heating zones. Each heating zone is set with a target temperature based on the actual heat dissipation characteristics of the tank. The target temperature for the lower part of the tank wall is set at 8 degrees Celsius, while the target temperature for the upper part is set at... The target temperature of the heating area is set at 5 degrees Celsius to ensure that the division matches the actual temperature control requirements. A corresponding power control unit is assigned to each independent heating unit. The power control unit is used to control the input power to the corresponding heating unit, and each heating unit uniquely corresponds to one power control unit to form a one-to-one control link. Each heating unit is equipped with an independent voltage and current acquisition channel, forming a dedicated control and data acquisition link from the main control module to the corresponding power control unit and then to the corresponding heating unit. This link has the characteristics of unidirectional signal transmission and independent data feedback to ensure that the control and monitoring of each heating unit do not interfere with each other, as shown in the control block diagram of a single heating unit in Figure 2.

[0038] For example, if a single heating area has 8 heating units, then there are 8 corresponding power control units. The output of each power control unit is connected to the input of the heating unit, and the input is connected to the corresponding output signal pin of the main control module. The main control module calculates the power input to each heating unit and adjusts the output signal of the corresponding pin. After being input to the corresponding power control unit, the conduction angle of the power control unit is adjusted. Furthermore, the real-time voltage and current data of each heating unit are fed back to the main control module through a dedicated acquisition channel, without data interaction with other control links.

[0039] The temperature value acquisition step involves acquiring the real-time voltage and current of each heating unit to obtain its real-time resistance value. Using this real-time resistance value as an index, a matching real-time heating temperature value is searched within a preset resistance-temperature baseline. The real-time heating temperature value represents the estimated intrinsic temperature of the heating unit at the current moment. This step first requires establishing a resistance-temperature baseline for the heating units through calibration experiments. The establishment process is as follows: In a simulated constant temperature chamber, the power input to the heating unit and the temperature of the chamber are adjusted, and the current operating conditions are kept constant for a period of time before collecting temperature and resistance values. When both the temperature change rate and resistance change rate of the heating unit are determined to be below a threshold, then... The previous step was to establish a stable state and record the resistance and temperature values ​​of the heating unit at that moment. The simulated constant temperature chamber refers to an experimental device capable of simulating different ambient temperature conditions and possessing precise temperature control and constant temperature maintenance capabilities. This device can achieve precise temperature control within a set temperature range, and the temperature fluctuation must meet experimental requirements. In this calibration test, the electric heating cable with the smallest independent heating element is used as the object, and the set ambient temperature of the simulated constant temperature chamber and the electrical power input to the heating unit are used as the experimental conditions. After each change in experimental conditions, the current experimental conditions must remain unchanged, allowing the heating unit to exchange heat under these conditions until its own temperature reaches thermal equilibrium with the ambient temperature, ensuring the obtained values ​​are accurate and consistent. Both the temperature and resistance values ​​are the actual values ​​of the heating unit after it has reached a stable thermal equilibrium state. To determine whether the heating unit has reached a stable thermal equilibrium state, threshold values ​​for the rate of temperature change and the rate of resistance change are set as judgment indicators. The rate of temperature change refers to the amount of temperature change of the heating unit per unit time, reflecting the trend of temperature change over time. The rate of resistance change refers to the amount of resistance change of the heating unit per unit time, reflecting the trend of resistance change over time. When both the actual rate of temperature change and the rate of resistance change of the heating unit are lower than the set threshold values, it is determined that it has reached a stable state. The recorded resistance value, temperature value, and ambient temperature value are combined into a set of data, and multiple sets of data are used to form a dataset. The dataset specifically includes multiple sets of resistance values, temperature values, and corresponding ambient temperature values ​​recorded after calibration experiments on the heating unit under different experimental calibration conditions. Subsequently, all data in the acquired dataset were processed and filtered to remove outliers caused by experimental errors, ensuring the accuracy and validity of the dataset. Then, the least squares method was used to perform curve fitting on the processed dataset. The curve corresponding to the obtained fitting function is the resistance-temperature baseline of the heating unit. The inherent characteristic of resistance adaptively adjusting to ambient temperature was incorporated into the baseline fitting process, resulting in the resistance-temperature baseline of the heating unit after ambient temperature compensation. The function corresponding to the baseline is... Where R is the real-time resistance value of the heating unit, in ohms, representing the actual resistance of the heating unit at a certain temperature, which is the core detection value calculated by collecting real-time voltage and current; T is the real-time heating temperature value of the heating unit, in degrees Celsius, representing the estimated self-temperature of the heating unit at the current moment, which is obtained by looking up the baseline from the resistance value. The coefficient of the quadratic term has a dimension of ohms per degree Celsius squared. It is determined by the nonlinear temperature resistance characteristics of the heating unit material and is a proportionality coefficient obtained by fitting, reflecting the rate of change of resistance with the square of temperature. The coefficient of the first term, with dimensions in ohms per degree Celsius, is the proportionality coefficient obtained from the fitting, reflecting the rate of linear change of resistance with temperature. The constant term, with the dimension of ohms, is the baseline constant obtained through fitting, representing the basic resistance value of the heating unit at a temperature of 0℃. After obtaining the resistance-temperature baseline, the validation data in the dataset that were not involved in the fitting calculation are selected and substituted into the fitting function to calculate the resistance value. This value is then compared with the actual measured resistance value. After obtaining the error, it is determined whether the error is within the experimental error range. Otherwise, it is necessary to continue to use the data in the dataset for fitting and adjustment to ensure the accuracy of the fitted resistance-temperature baseline.

[0040] The temperature acquisition step also includes a heating unit self-temperature correction sub-strategy. This sub-strategy is executed after the real-time heating temperature value is found from the resistance-temperature baseline. This sub-strategy eliminates the self-temperature error caused by the heating unit's aging and thermal coupling with adjacent units during actual operation through multi-dimensional correction compensation, thereby improving the accuracy of temperature detection and ensuring reliable temperature data for subsequent power allocation and temperature control. Specifically, it records the cumulative power-on time of each heating unit. The cumulative power-on time refers to the total power-on working time of a single heating unit from its initial operation to the current moment. This time is continuously accumulated and not interrupted by the start and stop of the heating unit. Because the long-term power-on operation of the heating unit causes slow changes in the physical properties of its internal PTC polymer heating material, resulting in self-temperature deviation, the duration aging correction amount is calculated using the cumulative power-on time. ; Duration aging correction The calculation is based on existing aging correction formulas, and the duration of aging correction has a negative correlation with the real-time heating temperature of the heating unit. The real-time heating temperature of the heating unit is obtained through resistance-temperature baseline matching, and the temperature difference between the heating unit and its adjacent units is calculated based on the real-time heating temperature of the heating unit and its adjacent units. Adjacent heating units refer to those physically adjacent to the target heating unit and exchanging heat through conduction and radiation. These adjacent heating units include those within the same heating region as the target heating unit and those across regions within other heating regions adjacent to the target heating unit's heating region. Adjacent heating units within a region and adjacent heating units across regions; because the target heating unit and its adjacent heating units have different temperatures, the existence of temperature differences causes heat exchange between the target heating unit and its adjacent heating units, resulting in a deviation in the estimation of the target heating unit's own temperature. Therefore, it is necessary to use a pre-set thermal coupling coefficient to calculate a thermal coupling correction amount for compensation. The thermal coupling coefficient refers to a coefficient obtained through experimental calibration beforehand, used to quantify the degree of thermal coupling between the target heating unit and a single adjacent heating unit. This coefficient is related to the physical spacing and laying method between the heating units, as well as the thermal conductivity of the carrier. Different adjacency relationships correspond to different thermal coupling coefficients, with values ​​ranging from 0 to 1. The formula for calculating the thermal coupling correction amount is as follows: ,in, This is a thermal coupling correction value, with dimensions in degrees Celsius, representing the compensation value for temperature estimation deviation caused by heat exchange between the target heating unit and adjacent heating units. The summation symbol represents the summation calculated over all adjacent heating units of the target heating unit, where m is the total number of adjacent heating units of the target heating unit, which is dimensionless. The thermal coupling coefficient between the target heating unit and the nth adjacent heating unit is dimensionless and ranges from 0 to 1. It is determined by experiments based on the spacing between the heating units and the thermal conductivity of the carrier. When the spacing and carrier are the same, a fixed value is taken. For example, it is 0.8 to 0.9 for adjacent units across the edge and 0.5 to 0.7 for adjacent units within the same area. The real-time heating temperature value of the nth adjacent heating unit is expressed in degrees Celsius. The original real-time heating temperature value of the target heating unit is found from the resistance-temperature baseline, with the dimension in degrees Celsius. Finally, the corrected real-time heating temperature value is obtained by summing the real-time heating temperature value of the heating unit with the time-aging correction and thermal coupling correction. The general formula for the corrected real-time heating temperature value is as follows: , This is the real-time heating temperature value after correction of the heating unit.

[0041] The compensation calculation step involves obtaining the measured temperature value of each heating zone and comparing it with the preset temperature value of each heating zone to obtain the temperature deviation of each heating zone. The temperature deviation is then substituted into the PID algorithm to obtain the power control amount corresponding to each heating zone.

[0042] Specifically, the measured temperature value of the aforementioned area refers to the actual temperature value accurately acquired by the temperature acquisition module when the heating area is in a thermal equilibrium stable state. Thermal equilibrium stable state means that after the main control module adjusts the input signal to the power control unit corresponding to each heating unit in the heating area, the power input must remain constant for a preset stable duration before acquiring the area temperature value. It is then determined whether the area temperature value meets the stability condition, i.e., when the temperature change rate is lower than the change threshold, it is considered a thermal equilibrium stable state. The acquired measured temperature value is a true reflection of the overall temperature state of the heating area and is also the actual value basis for temperature deviation calculation. The preset temperature value refers to the target temperature value pre-set for each heating area according to the actual temperature control requirements of the carrier. This value is entered into the main control module during the system configuration phase and can be adjusted locally or remotely according to actual working conditions. It is the target value basis for temperature deviation calculation. The PID algorithm used is a mature existing calculation method, a classic closed-loop control algorithm composed of proportional, integral, and derivative links. This algorithm performs proportional, integral, and derivative operations on the input temperature deviation signal to output a power control quantity that can eliminate the deviation.

[0043] The main control module executes a PID control algorithm at a fixed period, which can be 1 second. Specifically: ,in, is the proportional coefficient, which is a parameter of the proportional element in a PID controller; is the integral coefficient, which is a parameter of the PID integral element; These are the differential coefficients, which are parameters of the PID differential element; The temperature difference of the target heating area. , A target temperature value preset for the target heating area. The temperature acquisition module collects the measured temperature value of the target heating area; Output is the calculated control quantity, which is used to determine the conduction angle of the power regulation unit; in the actual arrayed electric heating cable heating control system, after the main control module calculates the output value, it also needs to calculate the allocation weight of each heating unit in the heating area according to the allocation strategy, and calculate the duty cycle of the PWM signal mapped to each heating unit, so that the power regulation unit output from the designated pin to the corresponding heating unit, i.e., the optocoupler-type bidirectional thyristor, adjusts the conduction of the heating unit, thereby completing the corresponding adjustment of the input power of each heating unit; after the allocation strategy, the Output value input to the power regulation unit that regulates each heating unit is calculated. When the calculated Output value is... When the ut value is close to its maximum value, it indicates that the main control module outputs a high duty cycle PWM signal, causing the thyristor of the power regulation unit to operate in a fully or nearly fully conducting state, thereby maximizing the power input to the heating unit. This allows for precise heating and regional temperature rise by independently controlling each heating unit in the region. When the calculated Output value decreases, the conduction angle of the corresponding power regulation unit decreases, thus reducing the power input to that heating unit. The above compensation calculation steps are executed independently for each heating region. The PID algorithm calculation for the temperature deviation of each heating region is independent, ensuring that different heating regions can accurately adjust their power according to their own temperature conditions. After calculating the power regulation amount, the main control module transmits the power regulation amount for each heating region to the temperature regulation step.

[0044] The temperature control step involves obtaining the corresponding compensation power for each heating unit in each heating zone according to the allocation strategy, and inputting it to the corresponding heating unit. The temperature value acquisition step, compensation calculation step, and temperature control step are repeated until the temperature deviation is less than the preset temperature difference threshold, so that the measured temperature value of the zone is close to the corresponding preset temperature value.

[0045] The allocation strategy in the above temperature control steps is as follows: First, obtain the relative position of each heating unit within the target heating area. This position refers to the specific orientation of a single heating unit within the target heating area. This position is categorized into three types: center position, internal position, and edge position. It is a spatial parameter that determines the power allocation weight and can be obtained by directly calling the pre-stored position information in the main control module. Second, obtain the relative position of the target heating area with respect to the carrier. This position is used to determine the adjacency relationship between the target heating area and other heating areas, and to determine whether cross-regional thermal coupling effects need to be considered. This position information can be obtained by directly calling the pre-stored position information in the main control module. Third, obtain the real-time heating temperature value of each heating unit within the target heating area. Here, the real-time heating temperature value refers to the accurate self-temperature value of the heating unit after correction by the self-temperature correction sub-strategy. This value reflects the heating temperature. The actual heating state of the heating unit is the core parameter for achieving on-demand power compensation. Obtaining the measured temperature values ​​of the target heating area and its adjacent heating areas is to consider the temperature of the adjacent heating areas when calculating the weight value of the heating unit located at the edge of the target heating area. Based on the relative position of each heating unit in the target heating area, the real-time heating temperature value, and the measured temperature values ​​of the heating areas adjacent to the target heating area, the power control allocation weight value corresponding to each heating unit in the target heating area is calculated. The weight value is specifically the proportion that a single heating unit should be allocated in the total power control amount of the target heating area. This value is a dimensionless value between 0 and 1, and the sum of the weight values ​​of all heating units in each heating area is 1. The compensation power of each heating unit is calculated based on the power control amount and the allocation weight value.

[0046] The specific steps for calculating the weight of each heating unit are as follows: Obtain the basic position coefficient of the target heating unit based on its location within the heating area. Dimensionless, it can be directly calibrated based on its location; the center of the heating area corresponds to... =0.8; the corresponding position inside the heating zone =1.0; located at the edge of the heating area =1.2; Based on the deviation between the real-time heating temperature of the target heating unit and the overall temperature of its heating area, on-demand power compensation is achieved, thereby obtaining the temperature deviation coefficient. Since it is dimensionless, the calculation formula is:

[0047] in, The measured temperature value of the heating area is expressed in degrees Celsius. The real-time heating temperature of the target heating unit after temperature correction is expressed in degrees Celsius. The thermal influence of the temperature of adjacent heating regions on the edge heating units is calculated only for heating units located at the edge of the target heating region. For heating units located at the center and interior, this coefficient is 0. The cross-region thermal coupling coefficient is also calculated. Since it is dimensionless, its calculation formula is:

[0048] in, The measured temperature value of the heating area is expressed in degrees Celsius. The measured temperature value of the heating region adjacent to the target heating unit is expressed in degrees Celsius. The initial comprehensive weight of the heating unit is obtained by combining the effects of location, temperature, and cross-regional thermal coupling on power distribution using the three single-factor coefficients mentioned above. Based on this formula, the initial weight of each heating unit in the target heating area can be calculated. Then, the initial weight of all heating units in the target heating area is normalized to ensure that the sum of the weights of all heating units is 1, achieving complete allocation of the total power control. Thus, the weight of each heating unit is obtained as follows:

[0049] in, Let be the initial weight of the i-th heating unit within the target heating area, where i is an integer from 1 to v, and v is the total number of heating units in the target heating area.

[0050] After calculating the weight values ​​for the power regulation amount, the main control module retrieves the total power regulation amount corresponding to the target heating area to calculate the compensation power for each heating unit. Then, the main control module outputs a signal to the power regulation unit corresponding to each heating unit and inputs the compensation power to the heating unit.

[0051] In addition, a compensation power adjustment strategy is incorporated into the temperature control process. This strategy is designed to ensure the safe and stable operation of the heating unit. By limiting the upper and lower limits of the heating unit's input power, it prevents damage caused by over-power operation or heating failure and energy waste due to under-power operation, while ensuring reasonable power adjustment and the lifespan of the heating unit. Specifically, the compensation power of each heating unit is summed with the current actual input power to obtain the total input power. The total input power is then compared with the rated maximum power; if it exceeds the rated maximum power, the rated maximum power is set as the input power of the heating unit. Conversely, the total input power is compared with the rated minimum power; if it is lower than the rated minimum power, the rated minimum power is set as the input power of the heating unit. The rated maximum power and rated minimum power mentioned above are electrical power limits calibrated during the design and production stages of the heating unit, ensuring long-term safe and stable operation.

[0052] Furthermore, the temperature control process involves repeated adjustments. During the repeated temperature value acquisition step, after inputting compensation power to each heating unit in the heating area, the power output needs to remain constant and remain stable for a preset duration before acquiring the regional temperature value of the heating area. The regional temperature value after determining whether the stability condition is met is used as the actual measured temperature value of the area. Specifically, the stability condition is the rate of temperature change obtained by using the ratio of the temperature difference between the current regional temperature value and the regional temperature value at the previous moment to time, and the rate of temperature change is lower than the change threshold. Through repeated temperature control adjustments, the temperature of the heating area gets closer and closer to the preset target temperature value until the temperature difference of the heating area is less than the preset temperature difference threshold.

[0053] In one embodiment of the present invention, a fault judgment strategy is set in the temperature control step. This strategy identifies abnormal operation of the heating unit and triggers a fault alarm in a timely manner by dual monitoring of the continuous compensation behavior of the heating area and the effect of temperature change after compensation. This avoids the failure of the carrier temperature control due to heating unit failure, and at the same time realizes early warning and location of abnormalities, reducing system maintenance costs. Specifically, the number of times the continuous compensation step is executed in each heating area is accumulated and compared with the set number threshold. If the number of times exceeds the threshold and the temperature deviation is still greater than the temperature difference threshold, it is determined that there is an abnormality in the heating unit under that heating area, and a fault alarm is triggered. The continuous compensation step refers to the continuous operation process of the heating area continuously executing the compensation calculation step and the temperature control step because the temperature deviation is greater than the temperature difference threshold. Each time the compensation power is input and the temperature value is collected after waiting for thermal equilibrium, it is considered as one compensation step. The number of continuous control steps is accumulated by the main control module. When the temperature deviation of the heating area is less than the temperature difference threshold, the counter is immediately cleared and the initial state is restored. The number of steps threshold refers to the upper limit of the number of consecutive compensation steps preset to determine whether there is an abnormality in the heating area; the measured temperature of the heating area after two adjacent compensation adjustments is obtained, the absolute value of the temperature change between the two adjacent measured temperatures is calculated and compared with the set change threshold. If it is less than the change threshold and the temperature deviation is still greater than the temperature difference threshold, it is determined that there is an abnormality in the heating unit in the heating area, and a fault alarm is triggered. The change threshold refers to the lower limit of the temperature change preset to determine whether the compensation adjustment of the heating area is effective. When the absolute value of the temperature change after two adjacent compensations is less than this value, it is considered that the compensation adjustment is invalid.

[0054] In a practical arrayed electric heating cable control system, after a fault alarm is triggered, the main control module will simultaneously execute multiple linkage operations. First, the fault information is transmitted to the human-machine interaction module in real time, and the location information of the fault heating area is displayed on the OLED screen, making it convenient for on-site operators to check in a timely manner. Second, the fault information is uploaded to the remote monitoring platform through the wireless communication module. The platform will immediately send an alarm notification to the management personnel, including key information such as the location of the fault area and the time of the fault, to achieve remote early warning.

[0055] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A method for controlling arrayed electric heating tape, characterized in that, The control method specifically includes: a control circuit establishment step, dividing the carrier into several heating areas, and setting multiple independent heating units in each heating area, with a power regulation unit configured for each heating unit to form a one-to-one control link; a temperature value acquisition step, acquiring the real-time voltage and real-time current of each heating unit to obtain the real-time resistance value of each heating unit, and using the real-time resistance value as an index to find the matching real-time heating temperature value in a preset resistance-temperature baseline, wherein the real-time heating temperature value represents the estimated self-temperature value of the heating unit at the current moment; a compensation calculation step, acquiring the measured temperature value of each heating area, comparing it with the preset temperature value of each heating area to obtain the temperature deviation of each heating area, and inputting the temperature deviation into a PID algorithm to obtain the power regulation amount corresponding to each heating area; a temperature regulation step, obtaining the corresponding compensation power of each heating unit in each heating area according to the power regulation amount of each heating area according to the allocation strategy, inputting it to the corresponding heating unit, and repeating the temperature value acquisition step, compensation calculation step, and temperature regulation step until the temperature deviation is less than a preset temperature difference threshold, so that the measured temperature value of the area is close to the corresponding preset temperature value.

2. The arrayed electric heating tape heating control method according to claim 1, characterized in that, The allocation strategy specifically involves: obtaining the relative position of each heating unit in the target heating area relative to the target heating area and obtaining the relative position of the target heating area relative to the carrier; obtaining the real-time heating temperature value of each heating unit in the target heating area, as well as the measured temperature value of the target heating area and the measured temperature value of the adjacent heating areas; Based on the relative position of each heating unit in the target heating area, the real-time heating temperature value, and the measured temperature value of the heating area adjacent to the target heating area, the power regulation allocation weight value corresponding to each heating unit in the target heating area is calculated, and the compensation power of each heating unit is obtained based on the power regulation allocation weight value.

3. The method for controlling arrayed electric heating tape according to claim 1, characterized in that, The temperature value acquisition step is configured with a heating unit self-temperature correction sub-strategy. After the real-time heating temperature value is found from the resistance-temperature baseline, the heating unit self-temperature correction sub-strategy is executed. Specifically, the cumulative power-on time of each heating unit is recorded, and the duration aging correction amount is calculated based on the cumulative power-on time. The real-time heating temperature value corresponding to the heating unit is obtained according to the resistance-temperature baseline, and the temperature difference between the heating unit and the adjacent heating unit is calculated based on the real-time heating temperature values ​​of the heating unit and the corresponding adjacent heating units. Then, the thermal coupling correction amount is calculated using a preset thermal coupling coefficient. The temperature value obtained by summing the real-time heating temperature value of the heating unit with the duration aging correction amount and the thermal coupling correction amount is used as the corrected real-time heating temperature value of the heating unit.

4. The arrayed electric heating tape heating control method according to claim 3, characterized in that, The adjacent heating units include adjacent heating units within the same heating area of ​​the heating unit, and cross-regional adjacent heating units in other heating areas that are adjacent to the heating area of ​​the heating unit.

5. The arrayed electric heating tape heating control method according to claim 1, characterized in that, The specific steps for establishing the resistance-temperature baseline are as follows: In a simulated constant temperature chamber, by adjusting the power of the input heating unit and the temperature of the constant temperature chamber, and keeping the current operating conditions unchanged and allowing it to remain stationary for a period of time, temperature and resistance values ​​are collected. When it is determined that both the temperature change rate and the resistance change rate of the heating unit are lower than the threshold, the current moment is considered a stable state, and the resistance and temperature values ​​of the heating unit at this time are recorded. The recorded resistance, temperature, and ambient temperature values ​​are combined into a set of data, and multiple sets of data form a dataset. By establishing a fitting relationship between the datasets, the resistance-temperature baseline of the heating unit is obtained.

6. The arrayed electric heating tape heating control method according to claim 1, characterized in that, In the repeated temperature value acquisition step, after inputting compensation power to each heating unit in the heating area, the power output is kept constant and the area temperature value of the heating area is collected after a preset stable time. The area temperature value that meets the stability condition is determined as the measured temperature value of the area. The stability condition is specifically the temperature change rate obtained by the ratio of the temperature difference between the current area temperature value and the area temperature value at the previous moment to the time, and the temperature change rate is lower than the change threshold.

7. The method for controlling arrayed electric heating tape according to claim 1, characterized in that, The temperature control step includes a fault judgment strategy, which specifically includes: accumulating the number of times each heating zone performs continuous compensation steps and comparing it with a set threshold number; if the number exceeds the threshold number and the temperature deviation is still greater than the temperature difference threshold, then it is determined that the heating unit in that heating zone is abnormal and a fault alarm is triggered; obtaining the measured temperature of the heating zone after two consecutive compensation adjustments, calculating the absolute value of the temperature change between the two consecutive measured temperatures, and comparing it with a set change threshold number; if the change is less than the change threshold number and the temperature deviation is still greater than the temperature difference threshold number, then it is determined that the heating unit in that heating zone is abnormal and a fault alarm is triggered.

8. The method for controlling arrayed electric heating tape according to claim 1, characterized in that, The temperature control step also includes a compensation power adjustment strategy, which is as follows: the compensation power of each heating unit is summed with the current actual input power to obtain the total input power; the total input power is compared with the rated maximum power; if it exceeds the rated maximum power, the rated maximum power is set as the input power of the heating unit; the total input power is compared with the rated minimum power; if it is lower than the rated minimum power, the rated minimum power is set as the input power of the heating unit.

9. A control system for arrayed electric heating tape, applicable to the control method for arrayed electric heating tape as described in any one of claims 1-8, characterized in that, The system includes: a main control module, which stores the control link addresses of all heating units and the resistance-temperature baseline, used for running compensation calculation steps and executing control logic tasks; a power drive and control module, including a power regulation unit corresponding to each heating unit, which receives control signals from the main control module to adjust the conduction of the power regulation unit and regulates the power input to the heating unit; a temperature acquisition module, used to acquire the measured temperature values ​​of each heating area; a power supply module, used to provide power to each module; a wireless communication module, used for data interaction between the main control module and the remote monitoring platform; a human-machine interaction module, used to display on-site working parameter information and allow local parameter setting and operation; and a remote monitoring platform, used to display the real-time operating parameters of each heating unit and to manage alarms and perform remote control.

10. A heating control system for arrayed electric heating cables according to claim 9, characterized in that, The heating unit is an electric heating tape.

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