An operating control method, device and system for an electric tracing heating system

Abstract

The present application relates to the technical field of electric tracing heating systems, and specifically relates to a method, device and system for operating and controlling an electric tracing heating system, which specifically includes: analyzing the severity of the heat compensation imbalance condition of the electric tracing caused by external strong convection and PTC characteristics, and constructing a heat compensation imbalance degree of the electric tracing; analyzing the heat compensation lag condition of the electric tracing for the heated body caused by heat inertia, and constructing a compensation response lag of the electric tracing; combining the two to construct a temperature compensation factor, obtaining the proportional term of the PID control system in the next control interval, and adjusting the power of the electric tracing heating system, reducing the heat compensation lag of the electric tracing heating system under unstable convective heat dissipation conditions, avoiding the drawback that the power output of the electric tracing heating system is frequently adjusted due to the influence of temperature response compensation lag, resulting in local overcooling of the heated body, and improving the temperature stability of the heated body.

Description

Technical Field

[0001] This application relates to the technical field of electric tracing heating systems, and specifically relates to a method, device, and system for controlling the operation of an electric tracing heating system. Background Art

[0002] An electric tracing cable is composed of a conductive polymer, two parallel metal wires, and an insulating protective layer. Because the conductive polymer has a high positive temperature coefficient characteristic and is connected in parallel with each other, it can automatically adjust the output power according to the temperature change of the heated system, automatically limit the heating temperature, and can be arbitrarily cut short or lengthened within a certain range, with the advantages of energy conservation, high efficiency, and strong adaptability. Electric tracing cables are usually divided into two types: self-limiting temperature electric tracing cables and constant power electric tracing cables. Due to the strong installation flexibility of self-limiting temperature electric tracing cables, they can automatically adjust the power to avoid overheating, and are mostly used to maintain the temperature stability of outdoor facilities such as solar energy, water pipes, eaves ramps, and tanks.

[0003] The core advantage of the self-limiting temperature electric tracing cable lies in its PTC characteristic, that is, the positive temperature coefficient effect. However, in the outdoor strong convection environment, the electric tracing heating system cannot linearly increase the power due to the intensification of the convection heat dissipation phenomenon, and cannot timely compensate for the heat loss, resulting in the breakage of the heat compensation balance; at the same time, under the action of the outdoor complex environment, the response control of the heating system has obvious hysteresis in the case of unstable convection heat dissipation, resulting in the need for frequent adjustment of the power output of the electric tracing heating system, which not only causes a sharp increase in instantaneous energy consumption, but also may bring local overcooling. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of this application is to provide a method, device, and system for controlling the operation of an electric tracing heating system, and the specific technical solutions adopted are as follows:

[0005] In the first aspect, an embodiment of this application provides a method for controlling the operation of an electric tracing heating system, and the method includes the following steps:

[0006] Take the area where each section of the electric tracing cable is located as a monitoring area in advance, and take the preset time period as a control interval; in each monitoring area within each control interval, collect the temperature of the electric tracing cable, the temperature of the heated body, and the external environment temperature at each moment, and construct an electric tracing cable temperature sequence, a heated body temperature sequence, and an environmental temperature sequence;

[0007] In each monitoring area within each control interval, construct the convective temperature difference of the electric tracing heating system based on the severity of data mutations in the ambient temperature sequence; construct the heat dynamic balance of the electric tracing heating system based on the degree of chaos in the temperature difference between the electric tracing and the external environment, as well as the overall temperature level of the electric tracing; construct the heat compensation imbalance of the electric tracing based on the convective temperature difference, heat dynamic balance, and the change trend of the heated body temperature sequence.

[0008] Based on the data changes in the heated body temperature sequence and the electric tracing temperature sequence, analyze the response delay degree between the cooling moment of the heated body and the corresponding heating moment of the electric tracing, and construct the temperature response delay of the electric tracing; construct the significance degree of the thermal inertia of the electric tracing based on the similarity of the electric tracing temperature data fluctuations between the corresponding heating moments of the electric tracing; construct the compensation response lag of the electric tracing based on the temperature response delay and the significance degree of the thermal inertia.

[0009] Take the normalized value of the product of the compensation response lag and the heat compensation imbalance in each monitoring area within each control interval as the temperature compensation factor for each monitoring area in each control interval.

[0010] Based on all the temperature compensation factors of each control interval, determine the proportional parameter of the PID control system in the next control interval, and use the PID control system to adjust the power of the electric tracing heating system.

[0011] In one embodiment, the method for obtaining the convective temperature difference is as follows:

[0012] Obtain each mutation point and its mutation probability in each ambient temperature sequence through a mutation point detection algorithm; calculate the mean value of all elements in the ambient temperature sequence, denoted as the first ambient temperature mean; take the absolute value of the difference between the temperature of each mutation point and the first ambient temperature mean as the first temperature difference of each mutation point; denote the sum value of the first temperature differences of all mutation points in the ambient temperature sequence as the first sum value.

[0013] Calculate the mean value of the mutation probabilities of all mutation points in the ambient temperature sequence, denoted as the first mean.

[0014] Take the product of the first sum value and the first mean as the convective temperature difference of the electric tracing heating system.

[0015] In one embodiment, the method for obtaining the heat dynamic balance is as follows:

[0016] Calculate the absolute value of the difference between the electric tracing temperature and the external environment temperature at each moment, denoted as the heat difference at each moment.

[0017] Denote the heat dynamic balance of the electric tracing heating system in the $i$-th monitoring area of the $t$-th control interval as , . The expression of

[0018] is: , where is the mean of all data in the electric tracing temperature sequence of the $i$-th monitoring area in the $t$-th control interval;

[0019] In one embodiment, the method for obtaining the heat compensation imbalance degree is:

[0020] Obtain the $Z$-value statistic of the heated body temperature sequence through the MK test method; Denote the heat compensation imbalance degree of the electric tracing in the $i$-th monitoring area of the $t$-th control interval as , . The expression of

[0021] is: , where is the convective temperature difference of the electric tracing heating system in the $i$-th monitoring area of the $t$-th control interval; is the $Z$-value statistic of the heated body temperature sequence of the $i$-th monitoring area in the $t$-th control interval; is the heat dynamic balance of the electric tracing heating system in the $i$-th monitoring area of the $t$-th control interval;

[0022] In one embodiment, the process for obtaining the temperature response delay degree is:

[0023] If the temperature of the heated body at a certain moment is greater than the temperature of the heated body at the next moment, then record the certain moment as the cooling moment of the heated body; If the temperature of the electric tracing at any moment is less than the temperature of the electric tracing at the next moment, then record the any moment as the heating moment of the electric tracing;

[0024] Calculate the time interval between any cooling moment of the heated body and each heating moment of the electric tracing in the time after it, and take the heating moment of the electric tracing corresponding to the minimum value of the time interval as the heat response moment of the any cooling moment of the heated body;

[0025] Denote the slope of each moment in the fitting curve of the heated body temperature sequence as the first slope, and denote the slope of each moment in the fitting curve of the electric tracing temperature sequence as the second slope; Calculate the difference between the absolute value of the first slope at each cooling moment of the heated body and the absolute value of the second slope at its heat response moment, and denote it as the first difference;

[0026] Calculate the absolute value of the difference between the temperature of the heated body at the cooling moment and the temperature of the electric tracing band at its heat response moment for each heated body, and denote it as the second difference; take the product of the sum of the first differences and the sum of the second differences at the cooling moments of all heated bodies as the temperature response delay degree of the electric tracing band.

[0027] In one embodiment, the process of obtaining the degree of thermal inertia significance is as follows:

[0028] Take the sequence composed of temperature data between each heat response moment and its next heat response moment as the compensation response sequence for each heat response moment; calculate the Pearson correlation coefficient between the compensation response sequences of any two heat response moments in the electric tracing band temperature sequence, and denote the sum of all the Pearson correlation coefficients in the electric tracing band temperature sequence as the second sum; calculate the variance of the elements in the electric tracing band temperature sequence, and denote it as the first variance;

[0029] Denote the degree of thermal inertia significance of the electric tracing band in the i-th monitoring area of the t-th control interval as , The expression of is:

[0030] , where, is the first variance of the electric tracing band temperature sequence in the i-th monitoring area of the t-th control interval; is the second sum of the electric tracing band temperature sequence in the i-th monitoring area of the t-th control interval; is a preset extremely small positive number.

[0031] In one embodiment, the compensation response lag is: the normalized value of the product of the temperature response delay degree and the degree of thermal inertia significance.

[0032] Based on all the temperature compensation factors of each control interval, determine the proportional parameter of the PID control system for the next control interval, and use the PID control system to adjust the power of the electric tracing band heating system. Specifically:

[0033] If the average value of the temperature compensation factors of all monitoring areas in the control interval is less than the preset temperature compensation threshold, do not adjust the electric tracing band heating system in the control interval;

[0034] Otherwise, calculate the difference between the temperature compensation factor of the current control interval and that of its previous control interval, and denote it as the first difference; take the sum of the temperature compensation factor of the current control interval and the first difference as the proportional parameter of the PID control system for the next control interval of the current control interval, take the preset temperature value of the heated body in the current control interval as the input, and adjust the output power of the electric tracing band through the control signal output by the PID control system.

[0035] In a second aspect, an embodiment of the present application further provides an operating control device for an electric tracing heating system. A computer program is stored in the device, and when the computer program is executed by a processor, the steps of the method described in the first aspect are implemented.

[0036] In a third aspect, an embodiment of the present application further provides an operating control system for an electric tracing heating system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of the method described in the first aspect are implemented.

[0037] The embodiments of the present application have at least the following beneficial effects:

[0038] In the present application, the heat compensation imbalance more accurately reflects the situation where the self-limiting electric tracing tape cannot linearly increase the power due to severe forced convection heat dissipation, resulting in the breakdown of the thermal balance. Compared with the prior art that only uses the temperature difference between the electric tracing tape and the heated body as the control basis for the heating system, the present application can accurately evaluate the increased heat dissipation of the self-limiting electric tracing tape affected by strong outdoor convection, and use this as part of the basis for the operation control of the electric tracing heating system, which can effectively contain the risk of the breakdown of the thermal balance and provide reliable and stable heat support for the heated body; by combining the compensation response lag of the electric tracing tape to construct a temperature compensation factor, determining the proportional term of the PID control system in the next control interval, and adjusting the power of the electric tracing heating system, it can effectively reduce the heat compensation lag of the electric tracing heating system under unstable convection heat dissipation conditions, avoid the frequent adjustment of the power output of the electric tracing heating system caused by the temperature response compensation lag, resulting in a sharp increase in instantaneous energy consumption and even causing local overcooling of the heated body, and improve the temperature stability of the heated body. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0040] Figure 1 It is a flowchart of the steps of an operating control method for an electric tracing heating system provided by an embodiment of the present application;

[0041] Figure 2 It is a schematic diagram for obtaining the convective temperature difference. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To further elaborate on the technical means and effects adopted by this application to achieve the intended invention purpose, the following specifically describes, in conjunction with the accompanying drawings and preferred embodiments, a method, device, and system for controlling the operation of an electric tracing heating system proposed according to this application, including its specific implementation manner, structure, features, and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which this application belongs.

[0044] The following specifically describes, in conjunction with the accompanying drawings, the specific solutions of a method, device, and system for controlling the operation of an electric tracing heating system provided by this application.

[0045] Please refer to Figure 1 , which shows a flowchart of the steps of a method for controlling the operation of an electric tracing heating system provided by an embodiment of this application. The method includes the following steps:

[0046] Step S1, taking the area where each section of the self-regulating electric tracing tape is located as a monitoring area, and taking the preset time duration as a control interval; in each monitoring area within each control interval, collect the temperature of the electric tracing tape, the temperature of the heated body, and the external environment temperature at each moment, and construct an electric tracing tape temperature sequence, a heated body temperature sequence, and an environmental temperature sequence.

[0047] This application uses a self-regulating electric tracing tape to heat the heated body. Among them, the electric tracing tape is wound around the heated body in a spiral manner, evenly distributed according to a winding coefficient of 1.4, and the minimum bending radius is greater than 5 times the thickness of the electric tracing tape.

[0048] Mark and divide the self-regulating electric tracing tape every 1 m, and take the area where each section of the divided self-regulating electric tracing tape is located as a monitoring area; in each monitoring area, collect the temperature of the electric tracing tape, the temperature of the heated body, and the external environment temperature at each moment through temperature sensors respectively.

[0049] It should be noted that for the marking and division of the self-regulating electric tracing tape, this application only provides one division method, and implementers can also use other division methods to mark and divide the self-regulating electric tracing tape, and this application does not make specific restrictions.

[0050] For the collection of the temperature of the electric tracing tape, the temperature of the heated body, and the external environment temperature, preferably, in the embodiments of this application, the temperature data collection frequency is set to 1 Hz. As other embodiments of this application, implementers can set the temperature data collection frequency according to the actual situation.

[0051] To prevent data loss in the various temperature data collected, the median filling method is used to fill the missing values in the time series of the temperature of the electric tracing band, the temperature of the heated body, and the ambient temperature respectively, and the wavelet transform algorithm is used to denoise the various temperature data collected to eliminate noise interference. Among them, the median filling method and the wavelet transform algorithm are both well-known technologies, and the specific acquisition process will not be elaborated.

[0052] Taking every 20 minutes as a control interval, the time series of the temperature of the electric tracing band, the temperature of the heated body, and the ambient temperature collected in each monitoring area within each control interval are respectively recorded as the electric tracing band temperature series, the heated body temperature series, and the ambient temperature series.

[0053] It should be noted that for the setting of the duration of the control interval, the present application only provides one setting method, and the implementer can also set the duration of the control interval to other values, and the present application does not make specific restrictions.

[0054] Step S2, in each monitoring area within each control interval, construct the convective temperature difference of the electric tracing band heating system based on the severity of data mutation in the ambient temperature series; construct the heat dynamic balance of the electric tracing band heating system based on the degree of chaos of the temperature difference between the electric tracing band and the external environment and the overall temperature level of the electric tracing band; construct the heat compensation imbalance degree of the electric tracing band based on the convective temperature difference, the heat dynamic balance, and the change trend of the heated body temperature series.

[0055] In an outdoor strong convection environment, the convective heat dissipation phenomenon will become more severe with the change of temperature difference. At this time, the rate of the convective heat dissipation condition is usually no longer a simple linear relationship. When the external environment convective heat dissipation phenomenon intensifies, the system needs to output a higher power to maintain the temperature of the heated body and compensate for the heat loss; however, limited by the PTC characteristics of the self-limiting temperature electric tracing band, when the external environment convective heat dissipation is severe but the temperature of the electric tracing band itself is relatively high, the power increase of the electric tracing band heating control system is limited, and it is more likely to cause the thermal balance to be broken.

[0056] When the self-limiting temperature electric tracing band is affected by the PTC characteristics and the intensified external strong convective heat dissipation, resulting in the risk of the heat loss not being compensated in time and the thermal balance being broken becoming higher, the greater the change in the external environment temperature, the more obvious the trend of heat loss through convection, and the more serious the impact of the outdoor strong convection condition on the heat loss of the heated body; at the same time, due to the resistance characteristics of the PTC material suppressing the power of the electric tracing band, the dynamic imbalance between the temperature of the electric tracing band and the ambient temperature becomes more significant.

[0057] To characterize the degree of heat compensation imbalance of the electric tracing band caused by the external strong convection and the PTC characteristics of the electric tracing band itself in each monitoring area within each control interval, the following processing is carried out:

[0058] (1) Take the environmental temperature sequences of each monitoring area in each control interval as the input of the Bayesian change point detection algorithm, and the output is each change point in the environmental temperature sequence and the change probability of each change point. Among them, the Bayesian change point detection algorithm is a well-known technology, and the specific process will not be elaborated.

[0059] It should be noted that for the detection of change points in the environmental temperature sequence, this application only provides a change point detection method. There are many existing change point detection methods, and implementers can also use other change point detection algorithms to detect change points in the environmental temperature sequence. This application does not make specific restrictions.

[0060] Further, in each monitoring area within each control interval, calculate the mean value of all elements in the environmental temperature sequence, denoted as the first environmental temperature mean value; calculate the absolute value of the difference between the temperature of each change point in the environmental temperature sequence and the first environmental temperature mean value, as the first temperature difference of each change point; denote the sum value of the first temperature differences of all change points in the environmental temperature sequence as the first sum value;

[0061] Calculate the mean value of the change probabilities of all change points in the environmental temperature sequence, denoted as the first mean value;

[0062] Further, determine the convective temperature difference of the electric tracing heating system in each monitoring area within each control interval based on the first sum value and the first mean value, where the convective temperature difference is positively correlated with the first sum value and the first mean value respectively.

[0063] Preferably, in the embodiment of this application, the expression of the convective temperature difference is: , in the formula, is the convective temperature difference of the electric tracing heating system in the i-th monitoring area within the t-th control interval, is the first sum value of the environmental temperature sequence in the i-th monitoring area within the t-th control interval, is the first mean value of the environmental temperature sequence in the i-th monitoring area within the t-th control interval.

[0064] It reflects the difference between the change point temperature and the overall temperature level in the environmental temperature sequence. When the environmental temperature change difference in the monitoring area within the control interval is larger and the environmental temperature change probability is higher, it means that the monitoring area is more severely affected by external strong convection in the control interval, and when the heat loss cannot be compensated in time, the environmental temperature difference caused by heat loss through convection is larger, and the degree of heat loss caused by the influence of strong convection on temperature is larger, and the calculated is larger.

[0065] When the electric tracing heating system is operating, within each monitoring area of each control interval, calculate the absolute value of the difference between the temperature of the electric tracing at each moment and the external ambient temperature, which is denoted as the heat difference at each moment.

[0066] Based on the degree of chaos in the distribution of heat differences at all moments within each monitoring area of each control interval, and the average temperature in the temperature sequence of the electric tracing, construct the heat dynamic balance of the electric tracing heating system within each monitoring area of each control interval. The expression is:

[0067] , where in the formula, is the heat dynamic balance of the electric tracing heating system in the i-th monitoring area of the t-th control interval; is the average value of all data in the temperature sequence of the electric tracing in the i-th monitoring area of the t-th control interval; is the information entropy of the heat differences at all moments in the i-th monitoring area of the t-th control interval. Among them, the information entropy is a well-known technology, and the specific process will not be elaborated.

[0068] The larger the , the higher the temperature of the electric tracing itself; The smaller the , the smaller the degree of chaos in the difference between the temperature of the electric tracing and the external ambient temperature; thus, the electric tracing is less inhibited by the PTC characteristic in the monitoring area, and the electric tracing can effectively respond to the change of the external ambient temperature and supplement heat in time; the heat dynamic balance characterizes the balance degree of the temperature difference between the electric tracing in the monitoring area of the control interval and the external environment caused by the inhibition of the PTC characteristic. The larger the heat dynamic balance, the smaller the possibility of the heat compensation imbalance of the electric tracing in the monitoring area.

[0069] For the temperature sequence of the heated body in each monitoring area of each control interval, obtain the Z-value statistic of the temperature sequence of the heated body through the Mann-Kendall (MK) test method. The smaller the Z-value statistic, the less obvious the trend of the temperature of the heated body in the short-term monitoring area rising steadily, that is, the more serious the heat loss of the heated body in the monitoring area caused by strong external convection, and the greater the possibility that the monitoring area is in a heat compensation imbalance state. Among them, the Mann-Kendall (MK) test method is a well-known technology, and the specific process will not be elaborated.

[0070] It should be noted that for the trend detection of the temperature sequence of the heated body, this application only provides a method for detecting the trend of time series data. There are many existing methods for detecting the trend of time series data, and implementers can also use other algorithms for detecting the trend of time series data to detect the trend of the temperature sequence of the heated body. This application does not make specific restrictions.

[0071] (4)Based on the above analysis, calculate the heat compensation imbalance degree of the electric tracing tape in each monitoring area within each control interval. The expression is as follows:

[0072] , where in the formula, is the heat compensation imbalance degree of the electric tracing tape in the i-th monitoring area within the t-th control interval; is the convective temperature difference of the electric tracing tape heating system in the i-th monitoring area within the t-th control interval; is the Z-value statistic of the temperature sequence of the heated body in the i-th monitoring area within the t-th control interval; is the heat dynamic balance of the electric tracing tape heating system in the i-th monitoring area within the t-th control interval; is a normalization function such that has a value range within [0, 1].

[0073] The heat compensation imbalance degree reflects the severity of the heat compensation imbalance of the electric tracing tape caused by strong external convection and PTC characteristics in this monitoring area within this control interval. The greater the heat compensation imbalance degree, the more serious the heat compensation imbalance of the electric tracing tape.

[0074] Step S3: Based on the data changes in the heated body temperature sequence and the electric tracing tape temperature sequence, analyze the response delay degree between the moment when the heated body cools down and the corresponding moment when the electric tracing tape heats up, and construct the temperature response delay degree of the electric tracing tape; based on the similarity of the fluctuations of the electric tracing tape temperature data between the corresponding moments when the electric tracing tape heats up, construct the significant degree of the thermal inertia of the electric tracing tape; based on the temperature response delay degree and the significant degree of the thermal inertia, construct the compensation response lag of the electric tracing tape.

[0075] During the operation of the electric tracing tape heating system, relying solely on the heat compensation imbalance degree of the self-limiting temperature electric tracing tape as the basis for temperature adjustment still has certain drawbacks. There is a lack of analysis of the thermal inertia of the PTC material of the self-limiting temperature electric tracing tape. Under the condition that the convective heat dissipation of the external environment is unstable, the adjustment lag of the power output makes the output power out of touch with the actual heat demand, easily causing local overcooling of the heated body before the preset temperature is reached, and also causing frequent adjustment of the output power of the electric tracing tape heating system.

[0076] When the external convective heat dissipation condition is unstable, resulting in a more serious adjustment lag of the power output of the electric heating tape due to the influence of thermal inertia, the cooling rate of the heated body is greater than the heating response of the electric heating tape; and when the heated body cools down, the power increase of the self-limiting temperature electric heating tape affected by thermal inertia shows a more obvious step pattern, and then the temperature increase of the self-limiting temperature electric heating tape shows a more obvious step pattern. Due to the influence of strong external convection on the heat transfer between the electric heating tape and the heated body, the temperature of the electric heating tape will also show an obvious fluctuation.

[0077] In order to analyze the heat compensation lag of the self-limiting temperature electric heating tape for the heated body in each monitoring area of each control interval, the following processing is carried out:

[0078] (1) For each monitoring area, taking the x-th moment as an example, if the temperature of the heated body at the x-th moment in this monitoring area is greater than the temperature of the heated body at its next moment y, then the x-th moment is recorded as the cooling moment of the heated body in this monitoring area; if the temperature of the electric heating tape at the x-th moment is less than the temperature of the electric heating tape at its next moment y, then the x-th moment is recorded as the heating moment of the electric heating tape in this monitoring area.

[0079] Furthermore, due to the influence of the thermal inertia of the PTC material, after each time the heated body is cooled by strong convection, the heating moment of the electric heating tape to adjust the power lags behind the cooling moment of the heated body. In each monitoring area of each control interval, obtain the heat response moment of each cooling moment of the heated body, specifically: calculate the time interval between any cooling moment of the heated body and each heating moment of the electric heating tape after this cooling moment of the heated body, and take the heating moment of the electric heating tape corresponding to the minimum value of the time interval as the heat response moment of this cooling moment of the heated body.

[0080] Furthermore, in each monitoring area of each control interval, respectively take the input of the least squares method of the heated body temperature sequence and the electric heating tape temperature sequence, and perform curve fitting respectively. The obtained fitting curves are respectively recorded as the heated body temperature fitting curve and the electric heating tape temperature fitting curve; record the slope at each moment in the fitting curve of the heated body temperature sequence as the first slope, and record the slope at each moment in the fitting curve of the electric heating tape temperature sequence as the second slope;

[0081] Calculate the difference between the absolute value of the first slope at each cooling moment of the heated body and the absolute value of the second slope at the corresponding heat response moment, and record it as the first difference;

[0082] Calculate the absolute value of the difference between the temperature of the heated body at each cooling moment of the heated body and the temperature of the electric heating tape at the corresponding heat response moment, and record it as the second difference.

[0083] (2) In each monitoring area of each control interval, based on the first difference and the second difference, construct the temperature response delay degree of the electric heating tape, and the expression is:

[0084] , where is the temperature response delay degree of the electric tracing band in the i-th monitoring area of the t-th control interval; is the sum value of all the second differences in the i-th monitoring area of the t-th control interval; is the sum value of all the first differences in the i-th monitoring area of the t-th control interval.

[0085] When the lag of the temperature adjustment of the thermal inertia power output of the electric tracing band caused by the unstable external convective heat dissipation condition is more serious, the delay between the cooling rate of the heated body and the heating response of the electric tracing band is higher, the temperature difference is more obvious, and the degree of mismatch of the heating response rate is greater, the greater.

[0086] (3) In the electric tracing band temperature sequence of each monitoring area in each control interval, the sequence composed of the temperature data between each heat response moment and its next heat response moment is used as the compensation response sequence of each heat response moment. Among them, the compensation response sequence acquisition is not performed on the last heat response moment in the electric tracing band temperature sequence.

[0087] Furthermore, calculate the Pearson correlation coefficient between the compensation response sequences of any two heat response moments in the electric tracing band temperature sequence, and record the sum value of all the Pearson correlation coefficients in the electric tracing band temperature sequence as the second sum value;

[0088] At the same time, calculate the variance of the elements in the electric tracing band temperature sequence, and record it as the first variance.

[0089] (4) Calculate the thermal inertia significance degree of the electric tracing band in each monitoring area of each control interval based on the second sum value and the first variance, and the expression is:

[0090] , where is the thermal inertia significance degree of the electric tracing band in the i-th monitoring area of the t-th control interval; is the first variance of the electric tracing band temperature sequence in the i-th monitoring area of the t-th control interval; is the second sum value of the electric tracing band temperature sequence in the i-th monitoring area of the t-th control interval; is a preset extremely small positive number, which functions to prevent the denominator from being 0. Preferably, in the embodiments of the present application, is set to 0.1. As other embodiments of the present application, the implementer can set according to the actual situation.

[0091] When the hysteresis of the temperature adjustment of the self-limiting heating cable caused by the unstable convective heat dissipation condition in the external environment is more serious, the self-limiting heating cable makes multiple adjustments due to the adjustment hysteresis, resulting in a more serious temperature fluctuation condition of the heating cable, and the temperature difference within the temperature rise response time range of the heating cable each time is obvious. The larger it is, the more obvious the temperature difference between the temperature ranges of the heating cable after each temperature rise is; The larger it is, the more obvious the temperature fluctuation condition of the heating cable is; thus The larger it is, the more serious the hysteresis of the temperature adjustment of the heat inertia power output of the heating cable caused by the unstable convective heat dissipation condition in the external environment is.

[0092] (5) Based on the above analysis, the compensation response hysteresis of the heating cable in each monitoring area of each control interval is constructed, and the expression is:

[0093]

[0094] In the formula, is the compensation response hysteresis of the heating cable in the i-th monitoring area of the t-th control interval; is the temperature response delay degree of the heating cable in the i-th monitoring area of the t-th control interval; is the significant degree of heat inertia of the heating cable in the i-th monitoring area of the t-th control interval; is the normalization function.

[0095] The temperature response delay degree reflects the delay between the cooling rate of the heated body and the temperature rise response of the heating cable in the monitoring area within the control interval; the significant degree of heat inertia reflects the obvious stepped state of the temperature rise of the heating cable and the temperature fluctuation degree of the electric heating cable caused by the influence of heat inertia in the monitoring area; thus, the compensation response hysteresis reflects the lagging state of the heat compensation of the heating cable for the heated body due to the influence of heat inertia in the monitoring area within the control interval.

[0096] Step S4, use the normalized value of the product of the compensation response hysteresis and the heat compensation imbalance degree in each monitoring area of each control interval as the temperature compensation factor for each monitoring area in each control interval.

[0097] During the operation of the heating cable heating system, when the heat compensation imbalance condition of the self-limiting heating cable in each monitoring area caused by the strong convection in the external environment is more serious, and the lagging condition of the heat compensation response of the heating cable in the monitoring area due to the influence of heat inertia is more obvious, it is more impossible to provide stable and reliable heat support for the heated body.

[0098] Based on the above analysis, the present application constructs a heat compensation factor to characterize the heat compensation degree of the electric tracing heating system within the control interval, and the expression is:

[0099]

[0100] Wherein, is the temperature compensation factor of the i-th monitoring area in the t-th control interval; and are respectively the heat compensation imbalance degree and the compensation response lag of the i-th monitoring area in the t-th control interval; is a normalization function, such that has a value range within [0, 1].

[0101] The heat compensation factor reflects the temperature lag compensation imbalance condition of the monitoring area in the control interval. When the self-limiting temperature electric tracing in the monitoring area within the control interval is affected by strong convection in the external environment and the thermal inertia of the PTC material, resulting in the breakdown of thermal equilibrium, the more obvious the heat compensation imbalance condition, and the stronger the heat compensation response lag of the electric tracing, it indicates that the heated body is less able to obtain reliable and stable heat support at this time, and it is more necessary to timely adjust the power of the electric tracing in the monitoring area to increase the temperature to ensure the temperature stability of the heated body.

[0102] Step S5: Based on all the temperature compensation factors of each control interval, determine the proportional parameter of the PID control system in the next control interval, and use the PID control system to adjust the power of the electric tracing heating system.

[0103] Set a temperature compensation threshold W. Preferably, in the embodiment of the present application, the value of W is set to 0.7. As other embodiments of the present application, the implementer can set the value of W according to the actual situation.

[0104] When the average value of the temperature compensation factors of all monitoring areas in the control interval is less than the temperature compensation threshold W, it is determined that the heat compensation imbalance and temperature compensation response lag conditions caused by strong convection in the external environment and the thermal inertia of the PTC material in the electric tracing heating system in the control interval are slight, and there is no need to adjust the electric tracing heating system in the control interval; while when the average value of the temperature compensation factors of all monitoring areas in the control interval is greater than or equal to the temperature compensation threshold W, it is determined that the heat compensation imbalance and temperature compensation response lag conditions caused by strong convection in the external environment and the thermal inertia of the PTC material in the electric tracing heating system in the control interval are serious, and the risk of breakdown of the thermal equilibrium of the heated body increases, and the self-limiting temperature electric tracing cannot provide stable and reliable heat support for the heated body, and it is necessary to timely adjust the power output of the electric tracing to increase the heat compensation of the electric tracing heating system. The specific adjustment method for the electric tracing heating system is as follows:

[0105] This application uses a PID control system to obtain the output power of the electric tracing heating system. The initial parameters of the proportional term, integral term, and derivative term in the PID control are set to 0.5, 0.45, and 0.6 respectively. Calculate the difference between the temperature compensation factor of each control interval and that of its previous control interval, which is denoted as the first difference. The sum of the temperature compensation factor of this control interval and the first difference is used as the proportional term of the next control interval of this control interval. The proportional term is used as the proportional parameter of the PID control system in the electric tracing heating system. The preset temperature value of the heated body in each control interval is used as the input. Preferably, in the embodiment of this application, the preset temperature of the heated body is set to 20 . As other embodiments of this application, the implementer can set the preset temperature of the heated body according to the actual situation. It should be noted that, in order to avoid the problem that the response of the control system is too slow due to too small a value of the proportional term, the lower limit of the proportional term is set to 0.4. The output power of the electric tracing belt is adjusted through the control signal output by the PID control system, thereby completing the control of the temperature of the self-limiting electric tracing belt. Among them, the PID control system is a well-known technology, and the specific process will not be elaborated.

[0106] The schematic diagram for obtaining the convective temperature difference is as Figure 2 shown.

[0107] Based on the same inventive concept as the above method, the embodiment of this application also provides an operating control device for an electric tracing heating system. A computer program is stored in the device, and when the computer program is executed by a processor, the steps of any one of the above methods for operating an electric tracing heating system are implemented.

[0108] Based on the same inventive concept as the above method, the embodiment of this application also provides an operating control system for an electric tracing heating system, including a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, the steps of any one of the above methods for operating an electric tracing heating system are implemented.

[0109] In summary, the embodiment of the present application provides a method for controlling the operation of an electric tracing heating system. The heat compensation imbalance more accurately reflects the situation where the self-limiting electric tracing belt cannot linearly increase the power due to severe forced convection heat dissipation, resulting in the breakdown of the thermal balance. Compared with the prior art that only uses the temperature difference between the electric tracing belt and the heated body as the control basis for the heating system, the present application can accurately evaluate the increased heat dissipation of the self-limiting electric tracing belt affected by outdoor forced convection, and use this as part of the basis for controlling the operation of the electric tracing heating system, which can effectively contain the risk of the breakdown of the thermal balance and provide reliable and stable heat support for the heated body; by combining the compensation response lag of the electric tracing belt to construct a temperature compensation factor, determining the proportional term of the PID control system in the next control interval, and adjusting the power of the electric tracing heating system, it can effectively reduce the heat compensation lag of the electric tracing heating system under unstable convection heat dissipation conditions, avoid the frequent adjustment of the power output of the electric tracing heating system caused by the temperature response compensation lag, resulting in a sudden increase in instantaneous energy consumption, and even causing the drawback of local overcooling of the heated body, and improve the temperature stability of the heated body.

[0110] It should be noted that the above sequence of embodiments of the present application is only for description and does not represent the superiority or inferiority of the embodiments. And the above specific embodiments of the present application have been described. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0111] The embodiments in the present application are all described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the key points of each embodiment are the differences from other embodiments.

[0112] The above are only the preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control method for the operation of an electric tracing heating system, characterized in that, The method includes the following steps: Taking the area where each pre-divided section of the electric tracing tape is located as a monitoring area, and taking a preset time duration as a control interval; in each monitoring area within each control interval, collecting the temperatures of the electric tracing tape, the heated body, and the external environment at each moment, and constructing an electric tracing tape temperature sequence, a heated body temperature sequence, and an environmental temperature sequence; In each monitoring area within each control interval, constructing the convective temperature difference of the electric tracing tape heating system based on the severity of data mutations in the environmental temperature sequence; constructing the heat dynamic balance of the electric tracing tape heating system based on the degree of chaos of the temperature difference between the electric tracing tape and the external environment, and the overall temperature level of the electric tracing tape; constructing the heat compensation imbalance degree of the electric tracing tape based on the convective temperature difference, the heat dynamic balance, and the change trend of the heated body temperature sequence; Based on the data changes in the heated body temperature sequence and the electric tracing tape temperature sequence, analyzing the response delay degree between the heated body cooling moment and the corresponding electric tracing tape heating moment, and constructing the temperature response delay degree of the electric tracing tape; constructing the thermal inertia significance degree of the electric tracing tape based on the similarity of the electric tracing tape temperature data fluctuations between the corresponding electric tracing tape heating moments; constructing the compensation response lag of the electric tracing tape based on the temperature response delay degree and the thermal inertia significance degree; Taking the normalized value of the product of the compensation response lag and the heat compensation imbalance degree in each monitoring area within each control interval as the temperature compensation factor for each monitoring area in each control interval; Based on all the temperature compensation factors of each control interval, determining the proportional parameter of the PID control system for the next control interval, and using the PID control system to adjust the power of the electric tracing tape heating system.

2. The operation control method of an electric tracing heating system according to claim 1, characterized in that The method for obtaining the convective temperature difference is as follows: Obtaining each mutation point and its mutation probability in each environmental temperature sequence through a mutation point detection algorithm; calculating the mean value of all elements in the environmental temperature sequence, denoted as the first environmental temperature mean; taking the absolute value of the difference between the temperature of each mutation point and the first environmental temperature mean as the first temperature difference of each mutation point; denoting the sum value of the first temperature differences of all mutation points in the environmental temperature sequence as the first sum value; Calculating the mean value of the mutation probabilities of all mutation points in the environmental temperature sequence, denoted as the first mean value; Taking the product of the first sum value and the first mean value as the convective temperature difference of the electric tracing tape heating system.

3. A method for controlling the operation of an electric tracing heating system according to claim 1, characterized in that, The method for obtaining the heat dynamic balance is as follows: Calculating the absolute value of the difference between the temperature of the electric tracing tape and the external environment at each moment, denoted as the heat difference at each moment; Denote the heat dynamic balance of the electric tracing heating system in the $i$-th monitoring area of the $t$-th control interval as , The expression of which is: , where is the mean of all data in the electric tracing tape temperature sequence of the i-th monitoring area in the t-th control interval; is the information entropy of the heat difference at all times in the i-th monitoring area in the t-th control interval.

4. The operation control method of an electric tracing heating system according to claim 1, wherein The method for obtaining the heat compensation imbalance degree is as follows: Obtain the Z-value statistic of the temperature sequence of the heated body through the MK test method; Denote the heat compensation imbalance degree of the electric tracing belt in the i-th monitoring area of the t-th control interval as , The expression of is: , where is the convective temperature difference of the electric tracing heating system in the i-th monitoring area of the t-th control interval; is the Z-value statistic of the temperature sequence of the heated body in the i-th monitoring area of the t-th control interval; is the heat dynamic balance of the electric tracing heating system in the i-th monitoring area of the t-th control interval; is the normalization function.

5. The operating control method of an electric tracing heating system according to claim 1, characterized in that The process for obtaining the temperature response delay degree is as follows: If the temperature of the heated body at a certain moment is greater than the temperature of the heated body at the next moment, then denoting the certain moment as the heated body cooling moment; if the temperature of the electric tracing tape at any moment is less than the temperature of the electric tracing tape at the next moment, then denoting the any moment as the electric tracing tape heating moment; Calculate the time interval between any heat-receiving body's cooling moment and each heating moment of the electric tracing band in the subsequent time, and take the heating moment of the electric tracing band corresponding to the minimum value of the time interval as the heat response moment of the any heat-receiving body's cooling moment; Denote the slope at each moment in the fitting curve of the heat-receiving body temperature sequence as the first slope, and denote the slope at each moment in the fitting curve of the electric tracing band temperature sequence as the second slope; calculate the difference between the absolute value of the first slope at each heat-receiving body's cooling moment and the absolute value of the second slope at its heat response moment, and denote it as the first difference; Calculate the absolute value of the difference between the heat-receiving body temperature at each heat-receiving body's cooling moment and the electric tracing band temperature at its heat response moment, and denote it as the second difference; take the product of the sum value of the first differences and the sum value of the second differences at all heat-receiving body's cooling moments as the temperature response delay degree of the electric tracing band.

6. The operation control method of an electric tracing heating system according to claim 5, characterized in that The process of obtaining the significant degree of thermal inertia is as follows: Take the sequence composed of the temperature data between each heat response moment and its next heat response moment as the compensation response sequence of each heat response moment; calculate the Pearson correlation coefficient between the compensation response sequences of any two heat response moments in the electric tracing band temperature sequence, and denote the sum value of all the Pearson correlation coefficients in the electric tracing band temperature sequence as the second sum value; Calculate the variance of the elements in the electric tracing band temperature sequence, and denote it as the first variance; Denote the thermal inertia significance level of the electric tracing tape in the \(i\)-th monitoring area of the \(t\)-th control interval as , The expression of which is: , where is the first variance of the electric tracing temperature sequence of the i-th monitoring area in the t-th control interval; is the second sum value of the electric tracing temperature sequence of the i-th monitoring area in the t-th control interval; is a preset extremely small positive number.

7. The operation control method of an electric tracing heating system according to claim 1, characterized in that, The compensation response lag is: the normalized value of the product of the temperature response delay degree and the significant degree of thermal inertia.

8. The operation control method of an electric tracing heating system according to claim 1, characterized in that, Based on all the temperature compensation factors in each control interval, determine the proportional parameter of the PID control system in the next control interval, and use the PID control system to adjust the power of the electric tracing band heating system. Specifically: If the average value of the temperature compensation factors in all monitoring areas in the control interval is less than the preset temperature compensation threshold, then do not adjust the electric tracing band heating system in the control interval; Otherwise, calculate the difference between the temperature compensation factors of the current control interval and its previous control interval, and denote it as the first difference; take the sum of the temperature compensation factor of the current control interval and the first difference as the proportional parameter of the PID control system in the next control interval of the current control interval, take the preset temperature value of the heat-receiving body in the current control interval as the input, and adjust the output power of the electric tracing band through the control signal output by the PID control system.

9. An operating control device for an electric tracing heating system, wherein a computer program is stored in the device, characterized in that, When the computer program is executed by the processor, it realizes the steps of an electric tracing band heating system operation control method as described in any one of claims 1-8.

10. An operating control system for an electric tracing heating system, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it realizes the steps of an electric tracing band heating system operation control method as described in any one of claims 1-8.

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