Intelligent control method and system for output power of electric heating cable

Abstract

The present invention relates to the field of constant temperature device control technology, and more specifically to a method and system for intelligently controlling the output power of an electric heating cable. The present invention first acquires temperature data, and further acquires the uniformity of the temperature change trend based on the change trend of the temperature data of all monitoring points; further segments the monitoring points, and acquires the constant temperature recovery coefficient of the pipeline at the current moment based on the change in the number of monitoring point segments at adjacent moments; further acquires the proportional gain correction coefficient at the current moment based on the delayed synchronous change of the temperature data of two adjacent monitoring points, combined with the uniformity of the temperature change trend and the constant temperature recovery coefficient; finally, adjusts the initial proportional gain coefficient at the current moment based on the proportional gain correction coefficient to control the output power of the electric heating cable, thereby achieving precise control of the output power of the heating cable and improving temperature uniformity, response speed, and energy efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of thermostat control, and in particular to a method and system for intelligently controlling the output power of an electric heating tape. Background Art

[0002] Electric heating is a technology that uses electrical energy to generate heat. By installing the electric heating tape on the surface of the pipeline, it generates heat when powered on to compensate for the heat loss of the pipeline, thereby maintaining the temperature of the medium in the pipeline.

[0003] Temperature control is generally carried out based on the difference between the set temperature and the actual temperature. The pipeline temperature is generally the average temperature of multiple monitoring points evenly distributed on the pipeline at the same time. Therefore, for the same pipeline temperature, the temperature distribution at different positions of the pipeline may be uniform or uneven. In addition, the reasons for the change of pipeline temperature are diverse, such as changes in ambient temperature, changes in the temperature of the liquid in the pipeline, etc., and the temperature change may recover quickly or slowly. Therefore, adjusting the output power of the electric heating cable only according to the difference between the set temperature and the actual temperature will lead to inaccurate control of the output power of the electric heating cable, affecting the constant temperature control effect. Summary of the Invention

[0004] In order to solve the technical problem that the existing control of the output power of electric heating cables is not accurate and affects the constant temperature control effect, the purpose of the present invention is to provide an intelligent control method and system for the output power of electric heating cables. The technical solutions adopted are as follows:

[0005] A method for intelligently controlling the output power of an electric heating cable, the method comprising:

[0006] Obtain temperature data at each sampling moment for all monitoring points on the pipeline;

[0007] Obtaining the uniformity of the temperature change trend at the current moment based on the change trend of the temperature data of all the monitoring points within the first preset neighborhood at the current moment; dividing the temperature data at the same moment based on the APCA algorithm to obtain corresponding monitoring point segments; obtaining the constant temperature recovery coefficient of the pipeline at the current moment based on the change in the number of monitoring point segments at adjacent moments within the second preset neighborhood at the current moment;

[0008] Acquire, along the flow direction of the material in the pipeline, temperature delay synchronization factors corresponding to the two adjacent monitoring points at the current moment based on delayed synchronous changes in the temperature data within a third preset neighborhood at the current moment; acquire, based on the distribution of all the temperature delay synchronization factors at the current moment, a proportional gain correction coefficient at the current moment in combination with the uniformity of the temperature change trend and the constant temperature recovery coefficient;

[0009] The initial proportional gain coefficient at the current moment is adjusted according to the proportional gain correction coefficient to control the output power of the electric heating tape.

[0010] Furthermore, the method for obtaining the uniformity of the temperature change trend includes:

[0011] Obtaining the latest first-order difference value and second-order difference value of the temperature data of each of the monitoring points within the first preset neighborhood;

[0012] Obtaining the same trend factor according to the dominant proportion of the non-positive and non-negative first-order difference values;

[0013] Obtaining a trend opposite factor according to a difference between the non-negative first-order difference value and the non-positive first-order difference value, in combination with a difference between the second-order difference value corresponding to the non-negative first-order difference value and the second-order difference value corresponding to the non-positive first-order difference value;

[0014] The same trend factor and the opposite trend factor are integrated to obtain the temperature change trend uniformity at the current moment.

[0015] Furthermore, the method for obtaining the trend identical factor includes:

[0016] Among the non-positive first-order difference values ​​and the non-negative first-order difference values, the ratio of the largest number of the first-order difference values ​​to the number of the monitoring points is used as the trend identity factor.

[0017] Furthermore, the method for obtaining the constant temperature recovery coefficient includes:

[0018] Select any moment as the target moment, and in the monitoring point segments of the next adjacent moment of the target moment, obtain the number of monitoring point segments that have monitoring point intersections with each monitoring point segment of the target moment as the number of splits of each monitoring point segment of the target moment;

[0019] The ratio of the sum of all the split numbers corresponding to the target moment to the number of the monitoring point segments is used as the split degree coefficient of the target moment;

[0020] The constant temperature recovery coefficient at the current moment is obtained based on the overall characteristics of the splitting degree coefficient and the downward trend strength of the number of monitoring point segments; the overall characteristics of the splitting degree coefficient are negatively correlated with the constant temperature recovery coefficient; the downward trend strength is positively correlated with the constant temperature recovery coefficient.

[0021] Furthermore, the method for obtaining the temperature delay synchronization factor includes:

[0022] Matching two adjacent monitoring points to form a matching group, and performing DTW matching on the temperature data corresponding to the two monitoring points in each matching group within a third preset neighborhood at the current moment;

[0023] According to the slope distribution between the matching data pairs in the DTW matching results of each matching group, the temperature delay synchronization factor of the matching group at the current moment is obtained.

[0024] Furthermore, the method for obtaining the temperature delay synchronization factor of the matching group at the current moment according to the slope distribution between the matching data pairs in the DTW matching results of each matching group includes:

[0025] For each matching group, the temperature delay synchronization factor of each matching group at the current moment is obtained based on the variance of the slopes between all matching pairs, the proportion of matching pairs with negative slopes, and the DTW distance.

[0026] Furthermore, the method for obtaining the proportional gain correction coefficient includes:

[0027] If the number of the temperature delay synchronization factors greater than the first preset threshold at the current moment is greater than the second preset threshold, it is determined that there is a raw material switch; otherwise, it is determined that there is no raw material switch;

[0028] When it is determined that there is no raw material switching, obtaining a proportional gain correction coefficient at the current moment according to the temperature change trend uniformity, the constant temperature recovery coefficient, and the temperature delay synchronization factor;

[0029] When it is determined that there is a raw material switch, the proportional gain correction coefficient at the current moment is obtained based on the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold, combined with the temperature change trend uniformity, the constant temperature recovery coefficient, and the temperature delay synchronization factor;

[0030] The temperature change trend uniformity, the constant temperature recovery coefficient and the temperature delay synchronization factor are all negatively correlated with the proportional gain correction coefficient; the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold is positively correlated with the proportional gain correction coefficient.

[0031] Furthermore, the method for controlling the output power of the electric heating tape includes:

[0032] The proportional gain correction coefficient is mapped to a preset correction interval, and the sum of the mapped proportional gain correction coefficient and a constant 1 is used as a correction factor; a corrected proportional gain coefficient is obtained according to the correction factor and the proportional gain coefficient, and the output power of the electric heating tape is controlled based on the corrected proportional gain coefficient.

[0033] Furthermore, the preset correction interval is [-0.2, 0.2].

[0034] The present invention also proposes an intelligent control system for the output power of an electric heating tape, the system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps of any one of the methods for intelligently controlling the output power of an electric heating tape are implemented.

[0035] The present invention has the following beneficial effects:

[0036] The present invention first obtains temperature data to provide a data basis for subsequent analysis; further, according to the change trend of the temperature data of all monitoring points, the uniformity of the temperature change trend is obtained, the uniformity of the temperature change trend is characterized, the heating effect of the electric heating tape is reflected, and the basis for the subsequent adjustment of the output power of the electric heating tape is provided; the monitoring points are further segmented, and according to the change in the number of monitoring point segments at adjacent moments, the constant temperature recovery coefficient of the pipeline at the current moment is obtained, the speed at which the pipeline restores temperature uniformity is quantified, and the proportional gain coefficient is assisted in adjusting; further, according to the delayed synchronous change of the temperature data of two adjacent monitoring points, the temperature delay synchronization factor is obtained, and the temperature of the adjacent monitoring points is quantified. The intensity of temperature delay synchronization change is used to distinguish the actual cause of uneven temperature in the pipeline, determine the most suitable adjustment method, and provide a basis for accurately adjusting the output power; further, based on the distribution of all temperature delay synchronization factors, combined with the uniformity of temperature change trend and constant temperature recovery coefficient, the proportional gain correction coefficient at the current moment is obtained, the real cause of temperature unevenness is accurately identified, the adaptability of the adjustment strategy is improved, and the accuracy and adaptability of the proportional gain adjustment are improved; finally, the initial proportional gain coefficient at the current moment is adjusted according to the proportional gain correction coefficient to control the output power of the electric heating cable, so as to achieve precise control of the output power of the heating cable and improve temperature uniformity, response speed and energy efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions and advantages of the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 A flow chart of an intelligent control method for output power of an electric heating cable provided by one embodiment of the present invention;

[0039] Figure 2 A schematic diagram of a constant power electric heating method provided by one embodiment of the present invention;

[0040] Figure 3A schematic diagram of a constant power electric heating tape wrapped around a pipe and monitoring point distribution provided by one embodiment of the present invention;

[0041] Figure 4 A schematic diagram of segmented comparison of monitoring points at adjacent moments provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0042] To further illustrate the technical means and effectiveness of the present invention in achieving its intended objectives, the following, in conjunction with the accompanying drawings and preferred embodiments, describes in detail the specific implementation, structure, features, and effectiveness of a method and system for intelligently controlling the output power of an electric heating cable according to the present invention. In the following description, references to "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

[0043] Unless defined otherwise, 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 belongs.

[0044] The specific scheme of the intelligent control method and system for the output power of an electric heating tape provided by the present invention is described in detail below with reference to the accompanying drawings.

[0045] See also Figure 1 , which shows a flow chart of an intelligent control method for output power of an electric heating cable provided by one embodiment of the present invention, specifically comprising:

[0046] Step S1: Obtain the temperature data of all monitoring points on the pipeline at each sampling moment.

[0047] In chemical production, many media are corrosive or prone to solidification, such as oleum and asphalt residue. Constant-wattage heating cables, through continuous and stable heating, effectively prevent freezing and blockage of pipelines, tanks, valves, and other equipment in low-temperature environments. For example, in the insulation of oleum pipelines, constant-wattage heating cables are used to maintain a temperature range of 15-18°C, preventing solidification and blockage of the oleum.

[0048] See also Figure 2 , which shows a schematic diagram of a constant power electric heating provided by an embodiment of the present invention. Figure 2 The figure shows a constant power type electric heat tracing including conductor, insulation, inner sheath, braiding and jacket from the inside out.

[0049] Constant power heating cables usually require a thermostat to control the temperature. The thermostat can adjust the output power of the heating cable according to the set temperature range to maintain the pipe temperature within the set range.

[0050] In one embodiment of the present invention, a constant power type electric heating cable is evenly wound around a pipeline in a chemical production process, and a number of monitoring points are set at equal intervals on the pipeline. Each monitoring point collects the temperature in real time through a temperature sensor. In this solution, each single-pass pipeline corresponds to a constant power type electric heating cable. Figure 3 , which shows a schematic diagram of a constant power electric heating tape wrapped around a pipeline and the distribution of monitoring points provided by an embodiment of the present invention, Figure 3 The figure shows how the constant power electric heating tape is wrapped around the pipeline, and the monitoring points are evenly distributed on the pipeline.

[0051] In one embodiment of the present invention, the acquisition frequency is 10 seconds per time, and the temperature data of each sampling moment of all monitoring points on the pipeline are obtained to provide a data basis for subsequent analysis.

[0052] Step S2: According to the change trend of the temperature data of all monitoring points in the first preset neighborhood at the current moment, the uniformity of the temperature change trend at the current moment is obtained; based on the APCA algorithm, the temperature data at the same moment is divided to obtain corresponding monitoring point segments; according to the change in the number of monitoring point segments at adjacent moments in the second preset neighborhood at the current moment, the constant temperature recovery coefficient of the pipeline at the current moment is obtained.

[0053] In temperature control, when the difference between the setpoint and the actual pipe temperature is small, but the pipe temperature is uneven, adjusting the proportional (P) value in the PID controller is a common method. The proportional control component is responsible for adjusting the control output based on the current temperature deviation. Therefore, this solution analyzes the temperature data from each monitoring point on the pipeline and adjusts the proportional gain coefficient to control the output power of the heating cable.

[0054] Since constant power electric heating cables provide constant heat output, they should theoretically produce a uniform heating effect on the entire pipeline. Therefore, the temperature change trend of all monitoring points reflects the uniformity of pipeline heating. Therefore, based on the change trend of the temperature data of all monitoring points in the first preset neighborhood at the current moment, the uniformity of the temperature change trend at the current moment is obtained, which characterizes the uniformity of the temperature change trend, reflects the heating effect of the electric heating cable, and provides a basis for subsequent adjustment of the output power of the electric heating cable.

[0055] Preferably, in one embodiment of the present invention, considering that the positive and negative signs of the first-order difference values ​​of the temperature data of the monitoring point can reflect the rising or falling trend of the temperature, the temperature rising is positive and the temperature falling is negative; at the same time, the second-order difference value can also reflect the changing trend of the temperature, which is negative when the temperature rises slower, falls faster, or rises first and then falls; and positive when the temperature rises faster, falls slower, or falls first and then rises, so within the first preset neighborhood, the latest first-order difference value and second-order difference value of the temperature data of each monitoring point are obtained, and the changing trend of the temperature data is analyzed with the help of the first-order difference value and the second-order difference value.

[0056] As an example, the first preset neighborhood is the last 3 seconds of the current moment, including the temperature at the current moment t, t-1, and t-2. For each monitoring point, the first-order difference value of the temperature at the current moment is obtained. , and the second-order difference value ,in 、 as well as are the temperatures at the x-th monitoring point at time t, time t-1, and time t-2 respectively.

[0057] Considering that the temperature change trends in most areas of the pipeline at the same time are similar, there are a large number of non-positive first-order difference values ​​or a large number of non-negative first-order difference values. The greater the dominant proportion of the signs of the first-order difference values, the trend similarity factor is obtained according to the dominant proportion of the non-positive and non-negative first-order difference values.

[0058] As an example, among the non-positive first-order difference values ​​and the non-negative first-order difference values, the non-positive number S1 and the non-negative number S2 of the first-order difference values ​​are counted, and the ratio of the maximum value of S1 and S2 to the number of monitoring points is used as the trend identity factor, that is, the ratio of the number of the largest number of first-order difference values ​​to the number of monitoring points is used as the trend identity factor. The larger the ratio, the greater the dominant proportion of a certain type of first-order difference value, and the stronger the same temperature change trend on the pipeline.

[0059] Considering that the temperature of the external environment varies at different locations on the pipeline, and that chemicals of different temperatures may be transported within the pipeline, this can lead to temperature differences in different areas of the pipeline at the same time, resulting in uneven temperature distribution on the pipeline. Therefore, the intensity of opposite temperature change trends at the same time is also analyzed.

[0060] Considering that the greater the difference between the non-negative first-order difference value and the non-positive first-order difference value, it means that the temperature rise degree in the temperature rising area of ​​the pipeline at the same time is greater, and the temperature drop degree in the temperature dropping area is greater, and the degree of opposite temperature change trend is stronger; the greater the difference between the second-order difference value corresponding to the non-negative first-order difference value and the second-order difference value corresponding to the non-positive first-order difference value, it means that the temperature rising trend and falling trend in different areas are stronger, and the degree of opposite temperature change trend is stronger;

[0061] Based on this, according to the difference between the non-negative first-order difference value and the non-positive first-order difference value, combined with the difference between the second-order difference value corresponding to the non-negative first-order difference value and the second-order difference value corresponding to the non-positive first-order difference value, the trend opposite factor is obtained;

[0062] As an example, the linearly normalized value of the difference between the mean Z2 of all non-negative values ​​in the latest first-order difference values ​​at the current moment and the mean Z1 of all non-positive values ​​is used as the first inverse factor; the difference between the mean U2 of the second-order difference values ​​corresponding to the non-negative first-order difference values ​​and the mean U1 of the second-order difference values ​​corresponding to the non-positive first-order difference values ​​is linearly normalized and used as the second inverse factor;

[0063] The product of the first opposite factor and the second opposite factor is taken as the trend opposite factor.

[0064] Finally, the same trend factor and the opposite trend factor are integrated to obtain the uniformity of the temperature change trend at the current moment. From the two perspectives of the same temperature change trend and the opposite temperature change trend at the same moment, the changing trend of the temperature data is shown, and the uniformity intensity of the temperature change trend on the pipeline is quantified.

[0065] As an example, the ratio of the factor with the same trend to the factor with the opposite trend is taken as the uniformity of the temperature change trend at the current moment.

[0066] In another embodiment of the present invention, considering that the better the uniform heating effect of the pipeline, the more consistent the temperature change trend, the more similar the current temperature, and the larger the variance of the temperature data of different monitoring points at the current moment, the greater the degree of temperature dispersion, which can be reflected from the side that the more uneven the temperature distribution is, the more uneven the temperature change trend is, so the first opposite factor is used as the numerator, the product of the second opposite factor and the variance of the temperature data is used as the denominator, and the fractional ratio is used as the uniformity of the temperature change trend.

[0067] Considering that the temperature data at the same time can be automatically divided into several temperature segments according to similarity based on the APCA algorithm, the monitoring points are also divided, and the corresponding monitoring point segments are obtained. The number of monitoring point segments can reflect the uneven heating and cooling of the pipeline;

[0068] Taking into account the changes in the number of monitoring point segments at adjacent moments, the evolution of the uniform temperature distribution of the pipeline is reflected. Therefore, according to the changes in the number of monitoring point segments at adjacent moments in the second preset neighborhood at the current moment, the constant temperature recovery coefficient of the pipeline at the current moment is obtained, the speed at which the pipeline restores temperature uniformity is quantified, and the proportional gain coefficient is assisted in adjusting to control the output power of the electric heating tape.

[0069] Preferably, in one embodiment of the present invention, the second preset neighborhood includes the six most recent collection time points (the current collection time point and the five most recent historical collection time points), and any time point is first selected as the target time point to facilitate analysis one by one;

[0070] See also Figure 4 , which shows a schematic diagram of segmented comparison of monitoring points at adjacent moments provided by an embodiment of the present invention; Figure 4 The figure contains the segmentation results of the monitoring points at time t1, time t2 and time t3, where t1 to t3 are in positive time sequence; each horizontal line represents all the monitoring points on the pipeline, the black dots represent the segmentation points, and the numbers are the segmentation numbers.

[0071] Considering that the pipeline shows a gradual temperature uniformity, the number of monitoring point segments decreases gradually with time, and some monitoring point segments at the target moment will be merged into one monitoring point segment at the next adjacent moment, such as Figure 4 Segments 3 and 4 of t1 are merged into 2 segments in t2; segments 1 and 2 of t2 are merged into 1 segment in t3. The more obvious the segment merging effect is, the fewer segments there are that intersect with the segment of the monitoring point at the next adjacent moment.

[0072] Based on this, in the monitoring point segments at the next adjacent moment of the target moment, the number of monitoring point segments that have monitoring point intersections with each monitoring point segment at the target moment is obtained as the number of splits of each monitoring point segment at the target moment;

[0073] The ratio of the sum of all the split numbers corresponding to the target moment to the number of monitoring point segments is used as the split degree coefficient at the target moment;

[0074] It is also considered that the more the number of segments shows a downward trend, the more the splitting of the monitoring point segments is alleviated and the temperature distribution tends to be uniform; at the same time, the smaller the overall characteristics of the splitting degree coefficient, the more uniform the temperature distribution and the better the constant temperature recovery. Therefore, the constant temperature recovery coefficient at the current moment is obtained according to the overall characteristics of the splitting degree coefficient and the downward trend strength of the number of monitoring point segments; the overall characteristics of the splitting degree coefficient are negatively correlated with the constant temperature recovery coefficient; the downward trend strength is positively correlated with the constant temperature recovery coefficient.

[0075] As an example, Figure 4As shown in the figure, segment 1 at t1 intersects with segment 1 at t2, resulting in a split of 1, denoted by t1-1 = 1. Segment 2 at t1 intersects with both segment 1 and segment 2 at t2, denoted by t1-2 = 2. Similarly, t1-3 = 1 and t1-4 = 1. The sum of all splits at t1 is 5, the number of monitoring point segments is 4, and the splitting coefficient is 5 / 4 = 1.25.

[0076] t2-1=1, t2-2=1, the sum of all split numbers at time t2 is 2, the number of monitoring point segments is 2, and the split degree coefficient is 1.

[0077] When the pipeline tends to be temperature-uniform, the segments are gradually merged. The closer the splitting degree coefficient is to 1 (gradually smaller), the larger the constant temperature recovery coefficient is. The change in the number of monitoring point segments is reflected from the perspective of segment splitting and merging.

[0078] In the second preset neighborhood at the current moment, the least squares method is used to obtain a fitting straight line showing the change of the number of monitoring point segments over time. The slope of the fitting straight line is obtained and linear normalization is performed to obtain K. The difference between the constant 1 and K is used as the numerator, representing the intensity of the downward trend in the number of monitoring point segments. The mean of all splitting degree coefficients is used as the denominator, representing the overall characteristics of the splitting degree coefficient. The fractional ratio is used as the constant temperature recovery coefficient.

[0079] It should be noted that the segmentation method of the APCA algorithm, the least squares method for fitting a straight line, and obtaining a slope are all technical means well known to those skilled in the art and will not be described in detail here.

[0080] In other embodiments of the present invention, implementers can also directly use the least squares method to obtain a fitted line showing the change in the number of monitoring point segments over time, obtain the slope of the fitted line, and apply a negative correlation mapping, such as using the exponential function exp(-x) with the natural constant e as the base, to the slope. The mapping result is used as the constant temperature recovery coefficient, with x as the independent variable. This eliminates the need to analyze the splitting degree coefficient, reduces the number of angles for analyzing changes in the number of monitoring point segments, sacrifices a certain degree of accuracy to improve computational efficiency, and places greater emphasis on the correction rate of the output power.

[0081] Step S3: along the flow direction of the material in the pipeline, according to the delayed synchronous change of the temperature data of the two adjacent monitoring points in the third preset neighborhood at the current moment, obtain the temperature delay synchronization factor corresponding to the two monitoring points at the current moment; according to the distribution of all temperature delay synchronization factors at the current moment, combined with the uniformity of the temperature change trend and the constant temperature recovery coefficient, obtain the proportional gain correction coefficient at the current moment.

[0082] During the chemical production process, the feed pipeline of the chemical reactor needs to add different raw materials or solvents in a specific order, or the source of the raw materials transported by the pipeline changes, and the temperature of the same raw materials changes, so chemicals of different temperatures may be transported in the pipeline.

[0083] Temperature fluctuations caused by material switching can cause significant temperature changes at the same monitoring point within a short period of time. This is because during the switching process, new raw materials begin to enter the pipeline before the old materials are completely discharged, causing a rapid temperature change within the pipeline. This temperature change will automatically and quickly recover as the raw material or solvent switch is completed. If the uneven pipeline temperature is caused by temperature changes in a certain link, the pipeline temperature will not have the automatic recovery feature.

[0084] Taking into account that different situations require different adjustments to the proportional gain coefficient, it is necessary to distinguish the actual causes of temperature unevenness. The temperature change caused by raw material switching will flow as the material flows in the pipeline, resulting in similar temperature changes at the monitoring points along the flow direction of the pipeline, showing the characteristics of delayed synchronous change. Therefore, along the flow direction of the material in the pipeline, according to the delayed synchronous change of the temperature data of the two adjacent monitoring points in the third preset neighborhood at the current moment, the temperature delay synchronization factor of the corresponding two monitoring points at the current moment is obtained, and the intensity of the temperature delay synchronous change of the adjacent monitoring points is quantified. This provides a basis for distinguishing the actual causes of pipeline temperature unevenness, determining the most appropriate adjustment method, and accurately adjusting the output power.

[0085] Preferably, in one embodiment of the present invention, considering that the Dynamic Time Warping (DTW) algorithm can optimally align two time series with nonlinear temporal offsets to minimize the overall distance between them, the slope between each pair of matching points can reflect the synchronization status on the time axis, thereby comparing and analyzing the delayed synchronization characteristics of the two temperature data series;

[0086] Based on this, two adjacent monitoring points are matched to form a matching group, and the temperature data corresponding to the two monitoring points in each matching group within the third preset neighborhood at the current moment are matched by DTW;

[0087] According to the slope distribution between the matching data pairs in the DTW matching results of each matching group, the temperature delay synchronization factor of the matching group at the current moment is obtained.

[0088] Preferably, in one embodiment of the present invention, the third preset neighborhood includes the current moment and the most recent 30 historical moments; each monitoring point is matched with the temperature data of the next monitoring point in the medium flow direction; considering that when the slope is less than zero, it indicates that there is a delay in the temperature data of the next monitoring point, the higher the proportion of matches with a negative slope, the more obvious the delay feature, and the smaller the variance of the slope and the DTW, the more concentrated the slope, the stronger the similarity of the temperature data, and the stronger the temperature delay synchronization;

[0089] Based on this, for each matching group, the temperature delay synchronization factor of each matching group at the current moment is obtained according to the variance of the slopes between all matching pairs, the proportion of matching pairs with negative slopes, and the DTW distance.

[0090] As an example, for each matching group, the variance of the slopes between all matching pairs is used as the denominator. After the DTW distance is negatively correlated with exp(-x), the product of the mapping value and the proportion of matching pairs with negative slopes is used as the numerator. The linear normalization result of the fractional ratio is used as the temperature delay synchronization factor of the corresponding matching group at the current moment.

[0091] It should be noted that the DTW algorithm is a technical means well known to those skilled in the art and will not be described in detail here.

[0092] Considering that the distribution of all temperature delay synchronization factors at the current moment reflects the main cause of temperature unevenness at the current moment, the temperature change trend uniformity represents the consistency strength of the current temperature change trend of the pipeline in the spatial distribution, and the constant temperature recovery coefficient represents the current ability of the pipeline to restore constant temperature, the proportional gain correction coefficient at the current moment is obtained based on the distribution of all temperature delay synchronization factors at the current moment, combined with the temperature change trend uniformity and the constant temperature recovery coefficient. This can accurately identify the true cause of temperature unevenness, improve the adaptability of the regulation strategy, enhance the accuracy and adaptability of the proportional gain adjustment, and prevent over- or under-regulation.

[0093] Preferably, in one embodiment of the present invention, since the change in ambient temperature is relatively slow, when the difference between the set temperature and the actual temperature of the pipeline is small, but the pipeline temperature is uneven, if the uneven pipeline temperature is caused by the switching of raw materials or solvents, it will recover faster as the switching is completed. In this case, it is necessary to reduce the proportional gain coefficient to reduce the direct response of the control output to the temperature deviation, that is, to prevent frequent changes in the output power of the electric heating tape, thereby reducing over-adjustment and under-adjustment, and contributing to the stability and uniform distribution of temperature.

[0094] If the uneven pipe temperature is caused by link temperature changes, the proportional gain coefficient needs to be increased to improve the response speed of the control output to temperature deviation, thereby accelerating the temperature recovery speed.

[0095] Considering that there are more large temperature delay synchronization factors, it means that the temperature data of adjacent monitoring points on the pipeline show a stronger characteristic of delayed synchronous change of temperature with the flow of the medium, which is more likely to be raw material switching. Therefore, if the number of temperature delay synchronization factors greater than the first preset threshold at the current moment is greater than the second preset threshold, it is determined that there is raw material switching, otherwise it is determined that there is no raw material switching; the distribution of all temperature delay synchronization factors is analyzed with the help of the first preset threshold and the second preset threshold.

[0096] As an example, the first preset threshold is 0.7, since the total number of all temperature delay synchronization factors is , set the second preset threshold to , S4 is the number of monitoring points on the pipeline; is a rounding function; obtain the number of temperature delay synchronization factors greater than 0.7 S3, when S3 is greater than , it is determined that there is a raw material switch; otherwise, it is determined that there is no raw material switch.

[0097] When it is determined that there is no raw material switching, the smaller the temperature change trend uniformity and the constant temperature recovery coefficient, the weaker the temperature uniform change trend and the trend of the pipeline restoring temperature uniformity, the stronger the impact of the environment on temperature unevenness, and the more adjustment is needed; at the same time, the smaller the temperature delay synchronization factor, the less likely there is raw material switching, and the more likely it is that the ambient temperature change causes the pipeline temperature unevenness. Therefore, a larger proportional gain coefficient is required at this time to increase the control output's response speed to temperature deviation, thereby accelerating the temperature recovery speed.

[0098] Based on this, the proportional gain correction coefficient at the current moment is obtained according to the temperature change trend uniformity, constant temperature recovery coefficient and temperature delay synchronization factor; the temperature change trend uniformity, constant temperature recovery coefficient and temperature delay synchronization factor are all negatively correlated with the proportional gain correction coefficient.

[0099] As an example, the product of the temperature change trend uniformity and the constant temperature recovery coefficient at the current moment is used as the independent variable, and is negatively correlated with exp(-x) and used as the first factor; the constant 1 minus the average value of the temperature delay synchronization factor is used as the second factor, and the linear normalized value of the product of the first factor and the second factor is used as the proportional gain correction coefficient.

[0100] When raw material switching is determined, the impact of ambient temperature changes during the chemical raw material switching process within the pipeline must also be considered. The fewer the number of temperature delay synchronization factors below the first preset threshold, the fewer monitoring points where the environment prevents adjacent monitoring points from exhibiting synchronized temperature delay changes. This weakens the environmental impact and requires a smaller proportional gain coefficient to reduce the control output's direct response to temperature deviations. This prevents frequent changes in the heating cable output power, thereby reducing overshoot and undershoot, and contributing to stable and uniform temperature distribution.

[0101] Based on this, according to the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold, combined with the temperature change trend uniformity, the constant temperature recovery coefficient and the temperature delay synchronization factor, the proportional gain correction coefficient at the current moment is obtained;

[0102] As an example, the calculation formula for the proportional gain correction factor includes:

[0103] ;

[0104] in Represents the proportional gain correction coefficient; represents the linear normalization function; Indicates the uniformity of temperature change trend; represents the constant temperature recovery coefficient; represents the mean value of the temperature delay synchronization factor; Indicates the number of temperature delay synchronization factors that are less than or equal to a first preset threshold; Indicates the total number of all temperature delay synchronization factors; Indicates the ratio of the temperature delay synchronization factor that is less than or equal to the first preset threshold.

[0105] In the calculation formula of the proportional gain correction coefficient, the temperature change trend uniformity and the constant temperature recovery coefficient are integrated by multiplication, and the proportional gain correction coefficient is calculated. Perform linear normalization so that 、 、 At the same order of magnitude, to avoid one factor dominating and causing other factors to have less influence; Represents the overall characteristics of the temperature delay synchronization factor, The smaller it is, the greater the environmental impact is, and the larger the proportional gain correction coefficient is; The larger the value, the wider the scope of environmental influence, the larger the proportional gain correction coefficient, and the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold is positively correlated with the proportional gain correction coefficient.

[0106] In other embodiments of the present invention, the implementer may also fuse the 、 、 , thereby obtaining the proportional gain correction coefficient.

[0107] Step S4: adjusting the initial proportional gain coefficient at the current moment according to the proportional gain correction coefficient to control the output power of the electric heating cable.

[0108] After obtaining the proportional gain correction coefficient and obtaining the basis for adjustment, the initial proportional gain coefficient at the current moment can be adjusted according to the proportional gain correction coefficient to control the output power of the electric heating cable, thereby achieving precise control of the output power of the electric heating cable and optimizing the temperature control effect.

[0109] Preferably, in one embodiment of the present invention, in order to control the correction range of the proportional gain coefficient, the proportional gain correction coefficient is mapped to a preset correction interval, and the sum of the mapped proportional gain correction coefficient and a constant 1 is used as a correction factor;

[0110] As an example, the preset correction interval is [-0.2, 0.2], the corresponding range of the correction factor is [0.8, 1.2], and the correction range of the proportional gain coefficient is 80% to 120%.

[0111] A corrected proportional gain coefficient is obtained according to the correction factor and the proportional gain coefficient, and the output power of the electric heating tape is controlled based on the corrected proportional gain coefficient.

[0112] As an example, the product of the correction factor and the proportional gain coefficient is used as the correction proportional gain coefficient.

[0113] It should be noted that the initial proportional gain coefficient at the current moment is a preset value, which can be obtained by a tuning method; in other embodiments of the present invention, it can also be obtained by any one or more methods such as empirical preset, trial and error method or response curve method, which will not be repeated here.

[0114] One embodiment of the present invention uses an adaptive PID controller to intelligently control the output power of the electric heating cable, wherein the adaptive PID control can adjust parameters in real time according to changes in system status, thereby improving control accuracy and response speed.

[0115] Based on the real-time temperature of all detection points on the pipeline, combined with the corrected proportional gain coefficient after real-time adjustment, an adaptive PID controller is used to achieve intelligent control of the output power of the electric heating cable, specifically:

[0116] (1) By installing temperature sensors, the temperature of each monitoring point on the pipeline surface is monitored in real time, and the temperature signal is transmitted to the control system.

[0117] (2) The intelligent controller automatically adjusts the output power of the electric heating cable based on the temperature data collected by the temperature sensor and the proportional gain coefficient adjusted in real time, combined with the preset temperature control strategy, to achieve precise temperature control.

[0118] (3) Through the communication module, the intelligent controller can exchange data with other devices to achieve remote monitoring and control.

[0119] Therefore, by analyzing the collected data, the temperature control effect is optimized to achieve precise control of the output power of the electric heating tape, reduce energy consumption, and improve the reliability and safety of the electric heating tape.

[0120] An embodiment of the present invention also provides an intelligent control system for the output power of an electric heating tape, which includes a memory, a processor, and a computer program, wherein the memory is used to store the corresponding computer program, and the processor is used to run the corresponding computer program. When the computer program runs in the processor, it can implement an intelligent control method for the output power of an electric heating tape described in steps S1-S4.

[0121] In summary, in response to the technical problem that the existing control of the output power of electric heating tape is not precise and affects the constant temperature control effect, the present invention proposes an intelligent control method and system for the output power of electric heating tape. The present invention first obtains temperature data, and further obtains the uniformity of the temperature change trend based on the change trend of the temperature data of all monitoring points; further divides the monitoring points into segments, and obtains the constant temperature recovery coefficient of the pipeline at the current moment based on the change in the number of monitoring point segments at adjacent moments; further, based on the delayed synchronous change of the temperature data of two adjacent monitoring points, combined with the uniformity of the temperature change trend and the constant temperature recovery coefficient, obtains the proportional gain correction coefficient at the current moment; finally, according to the proportional gain correction coefficient, the initial proportional gain coefficient at the current moment is adjusted to control the output power of the electric heating tape, thereby achieving precise control of the output power of the electric heating tape and improving temperature uniformity, response speed and energy efficiency.

[0122] It should be noted that the order in which the embodiments of the present invention are described above is for illustrative purposes only and does not necessarily represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0123] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments.

Claims

1. An intelligent control method for output power of an electric heating cable, characterized in that: The method comprises: Obtain temperature data at each sampling moment for all monitoring points on the pipeline; Obtaining the uniformity of the temperature change trend at the current moment based on the change trend of the temperature data of all the monitoring points within the first preset neighborhood at the current moment; dividing the temperature data at the same moment based on the APCA algorithm to obtain corresponding monitoring point segments; obtaining the constant temperature recovery coefficient of the pipeline at the current moment based on the change in the number of monitoring point segments at adjacent moments within the second preset neighborhood at the current moment; Acquire, along the flow direction of the material in the pipeline, temperature delay synchronization factors corresponding to the two adjacent monitoring points at the current moment based on delayed synchronous changes in the temperature data within a third preset neighborhood at the current moment; acquire, based on the distribution of all the temperature delay synchronization factors at the current moment, a proportional gain correction coefficient at the current moment in combination with the uniformity of the temperature change trend and the constant temperature recovery coefficient; Adjusting the initial proportional gain coefficient at the current moment according to the proportional gain correction coefficient to control the output power of the electric heating cable; The method for obtaining the uniformity of the temperature change trend includes: Obtaining the latest first-order difference value and second-order difference value of the temperature data of each of the monitoring points within the first preset neighborhood; Obtaining the same trend factor according to the dominant proportion of the non-positive and non-negative first-order difference values; Obtaining a trend opposite factor according to a difference between the non-negative first-order difference value and the non-positive first-order difference value, in combination with a difference between the second-order difference value corresponding to the non-negative first-order difference value and the second-order difference value corresponding to the non-positive first-order difference value; The uniformity of the temperature change trend at the current moment is obtained by fusing the same trend factor and the opposite trend factor; The method for obtaining the constant temperature recovery coefficient includes: Select any moment as the target moment, and in the monitoring point segments of the next adjacent moment of the target moment, obtain the number of monitoring point segments that have monitoring point intersections with each monitoring point segment of the target moment as the number of splits of each monitoring point segment of the target moment; The ratio of the sum of all the split numbers corresponding to the target moment to the number of the monitoring point segments is used as the split degree coefficient of the target moment; Obtaining the constant temperature recovery coefficient at the current moment according to the overall characteristics of the splitting degree coefficient and the downward trend strength of the number of monitoring point segments; the overall characteristics of the splitting degree coefficient are negatively correlated with the constant temperature recovery coefficient; and the downward trend strength is positively correlated with the constant temperature recovery coefficient; The method for obtaining the temperature delay synchronization factor includes: Matching two adjacent monitoring points to form a matching group, and performing DTW matching on the temperature data corresponding to the two monitoring points in each matching group within a third preset neighborhood at the current moment; According to the slope distribution between the matching data pairs in the DTW matching results of each matching group, the temperature delay synchronization factor of the matching group at the current moment is obtained.

2. The method for intelligently controlling the output power of an electric heating tape according to claim 1, characterized in that: The method for obtaining the trend identical factor includes: Among the non-positive first-order difference values ​​and the non-negative first-order difference values, the ratio of the largest number of the first-order difference values ​​to the number of the monitoring points is used as the trend identity factor.

3. The method for intelligently controlling the output power of an electric heating cable according to claim 1, characterized in that: The method for obtaining the temperature delay synchronization factor of the matching group at the current moment according to the slope distribution between the matching data pairs in the DTW matching results of each matching group includes: For each matching group, the temperature delay synchronization factor of each matching group at the current moment is obtained based on the variance of the slopes between all matching pairs, the proportion of matching pairs with negative slopes, and the DTW distance.

4. The method for intelligently controlling the output power of an electric heating tape according to claim 1, wherein: The method for obtaining the proportional gain correction coefficient includes: If the number of the temperature delay synchronization factors greater than the first preset threshold at the current moment is greater than the second preset threshold, it is determined that there is a raw material switch; otherwise, it is determined that there is no raw material switch; When it is determined that there is no raw material switching, obtaining a proportional gain correction coefficient at the current moment according to the temperature change trend uniformity, the constant temperature recovery coefficient, and the temperature delay synchronization factor; When it is determined that there is a raw material switch, the proportional gain correction coefficient at the current moment is obtained based on the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold, combined with the temperature change trend uniformity, the constant temperature recovery coefficient, and the temperature delay synchronization factor; The temperature change trend uniformity, the constant temperature recovery coefficient and the temperature delay synchronization factor are all negatively correlated with the proportional gain correction coefficient; the proportion of the temperature delay synchronization factor that is less than or equal to the first preset threshold is positively correlated with the proportional gain correction coefficient.

5. The method for intelligently controlling the output power of an electric heating tape according to claim 1, characterized in that: The method for controlling the output power of the electric heating tape comprises: The proportional gain correction coefficient is mapped to a preset correction interval, and the sum of the mapped proportional gain correction coefficient and a constant 1 is used as a correction factor; a corrected proportional gain coefficient is obtained according to the correction factor and the proportional gain coefficient, and the output power of the electric heating tape is controlled based on the corrected proportional gain coefficient.

6. The method for intelligently controlling the output power of an electric heating tape according to claim 5, characterized in that: The preset correction interval is [-0.2, 0.2].

7. An intelligent control system for output power of an electric heating cable, the system comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for intelligently controlling the output power of an electric heating tape as described in any one of claims 1 to 6 are implemented.

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