Resistance type steam overheating system capable of accurately controlling temperature and control method

Abstract

The invention relates to the technical field of industrial fluid heating, and discloses a precise temperature control resistance type steam overheating system and a control method, the precise temperature control resistance type steam overheating system comprises a sectional type self-sensing heating core, the sectional type self-sensing heating core is composed of a plurality of electrically independent heating sections made of materials with preset resistance temperature coefficients, and the heating sections have heating and temperature sensing functions. The driving and measuring module measures the dynamic resistance value of the heating section in real time while applying main heating power to the heating section. And the processing and control module calculates the real-time temperature of each section based on the resistance value, and reconstructs a dynamic thermal field profile representing on-way temperature distribution. According to the method, the state of the internal thermal field is changed from an unobservable state into a state variable which can be quantitatively monitored in real time and with high resolution, and closed-loop control and unbalanced power distribution are carried out based on the profile, so that the measurement lag is fundamentally eliminated, and the temperature control response speed and stability of the system under a dynamic working condition are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of industrial fluid heating technology, specifically to a resistance-type steam superheating system and control method for precise temperature control. Background Technology

[0002] Steam superheating technology plays a crucial role in modern industrial production, widely applied in power generation, chemical engineering, materials processing, and food processing. In these applications, precise and stable temperature control of superheated steam directly impacts production efficiency, product quality, and even equipment safety. One common method for achieving steam superheating is the use of resistance heaters, which are widely used due to their simple structure, relatively fast response, and ease of control.

[0003] However, existing resistance-type steam superheating systems often have inherent limitations in their structural design and control strategies. In these systems, the temperature measurement point and the heating execution point are physically separated. Typically, the temperature sensor is located downstream of the heating element to monitor the final steam temperature. This spatial separation leads to unavoidable measurement lag. This lag consists of two parts: first, the time required for heat to transfer from the heating element to the steam and then be carried by the steam to the sensor location; and second, the thermal inertia of the sensor itself.

[0004] This delay in information acquisition means the control system always adjusts based on past states. Furthermore, the controller can only acquire a single, mixed and delayed outlet temperature value, while the actual temperature distribution along the heating core remains completely unknown. This makes the entire heating process a black box for the controller, preventing it from gaining insight into and intervening in the internal thermodynamic dynamics.

[0005] The delay and incompleteness of this information acquisition directly restrict the dynamic performance of the control system. When faced with rapid fluctuations in operating conditions such as steam flow, inlet temperature, or pressure, traditional feedback controllers such as PID controllers, which rely on lagging temperature feedback, often do not respond quickly enough. They are prone to significant temperature overshoot and continuous oscillations during the adjustment process, making it difficult to meet the stringent temperature stability requirements of some high-precision applications.

[0006] Therefore, how to overcome measurement lag, obtain real-time thermal field information inside the system, and thereby achieve rapid, stable, and accurate dynamic control of steam temperature is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a precise temperature-controlled resistance-type steam superheating system and control method. It solves the problem that existing resistance-type steam superheating systems suffer from response delays, overshoot, and fluctuations when faced with fluctuations in operating conditions such as steam flow, due to the physical separation of the heating element and temperature measuring point, as well as the inherent thermal inertia of the system. This makes it difficult to achieve high-precision dynamic temperature control.

[0008] To address the aforementioned technical problems, this invention provides a resistance-type steam superheating system and control method for precise temperature control.

[0009] The first aspect of this invention provides a resistance-type steam superheating system with precise temperature control, the system comprising:

[0010] The heating and sensing module includes a segmented self-sensing heating core arranged along the steam flow direction. The segmented self-sensing heating core consists of multiple electrically independent heating sections, and the heating sections are made of a material with a preset, stable temperature coefficient of resistance.

[0011] The driving and measurement module is electrically connected to each heating segment in the heating and sensing module. The driving and measurement module is configured to perform dual functions: first, to apply main heating power to the heating segment to heat steam; second, to measure the dynamic resistance value of each heating segment in real time and continuously by superimposing a high-frequency, low-amplitude detection AC signal onto the main heating power and demodulating the signal using a lock-in amplifier.

[0012] A processing and control module, which is communicatively connected to the drive and measurement module, is configured to perform the following operations:

[0013] Dynamic thermal profile reconstruction: The processing and control module is based on the dynamic resistance value R of each heating segment received from the drive and measurement module. i (t), and the pre-calibrated reference resistance value R i,ref The real-time temperature T of each heating section is calculated using the following formula, based on the material's temperature coefficient of resistance α. i (t):

[0014]

[0015] Among them, T ref This is the reference temperature used to calibrate the base resistance value. Furthermore, the real-time temperature values ​​of all heating sections are combined into a vector to reconstruct a dynamic thermal field profile T that characterizes the temperature distribution along the segmented self-sensing heating core. profile (t).

[0016] Online thermodynamic parameter identification: The processing and control module is configured to perform active thermal wave detection periodically or as needed. This process includes controlling the drive and measurement module to superimpose an angular frequency of W onto the main heating power applied to the upstream heating section. tw The power disturbance forms a heat wave. By monitoring the temperature response of other downstream heating sections, the location of this heat wave between any two heating sections S is analyzed and extracted. i and S j Phase delay Δφ propagating between ij Based on this phase delay, the effective steam velocity is identified using the following formula. :

[0017]

[0018] Among them, L ij The heating section S i From the center to the heating section S j The physical distance between the centers.

[0019] Hierarchical control and power allocation: The processing and control module employs a hierarchical control strategy to generate power control signals. This strategy includes:

[0020] The feedforward control layer calculates the compensatory main heating power in advance based on the real-time changes in steam flow measured by the flow meter at the system inlet.

[0021] The inner ring profile control layer aims to maintain a preset optimal thermal field profile T. profile,ideal This layer calculates the dynamic thermal field profile T. profile (t) and the optimal thermal field profile T profile,ideal Vector error E between profile (t) is used to generate the power adjustment amount, and the formula for calculating the vector error is:

[0022] E profile (t)=T profile,ideal -T profile (t);

[0023] The outer loop setpoint tracking layer adjusts based on the deviation between the actual temperature measured by the temperature sensor at the system's main outlet and the final target temperature to eliminate steady-state errors. Finally, the processing and control module integrates the outputs of each control layer and performs unbalanced power distribution on the multiple heating sections to generate and output the final power control signal.

[0024] A second aspect of this invention provides a method for precise temperature control of resistive steam superheating, which is applied to the aforementioned system and includes the following steps:

[0025] S1. Using the driving and measurement module, measure the dynamic resistance value of each heating segment in the segmented self-sensing heating core in real time;

[0026] S2. Based on the dynamic resistance value measured in step S1 and the temperature coefficient of resistance of the heating section material, the temperature of each heating section is calculated in real time, thereby reconstructing the dynamic thermal field profile.

[0027] S3. Based on the comparison results between the dynamic thermal field profile reconstructed in step S2 and one or more target control states, generate and distribute power control signals to each of the heating segments to drive the heating segments to generate heat.

[0028] This invention provides a resistance-type steam superheating system and control method for precise temperature control. It offers the following advantages:

[0029] 1. This invention employs a segmented self-sensing heating core, enabling the heating segment itself to function as a temperature sensor. This fundamentally eliminates the measurement lag and spatial errors caused by traditional external sensors due to heat conduction delays and installation position deviations. This structure allows the system to acquire real-time temperature information that directly reflects the state of the heating element itself without delay, providing a high-fidelity state feedback basis for achieving rapid and accurate dynamic control.

[0030] 2. By reconstructing the real-time temperatures of multiple heating sections into a dynamic thermal field profile, this invention overcomes the limitations of traditional control methods that rely solely on the temperature of a single outlet point. This allows the controller to gain insight into the thermodynamic processes within the system, such as the evolution of temperature gradients and the internal propagation of disturbances. Consequently, it enables forward-looking, profile-based control decisions based on more comprehensive state information, rather than simply providing lag compensation for the final result.

[0031] 3. This invention introduces a hierarchical control strategy that combines feedforward control, inner-loop profile control, and outer-loop setpoint tracking. The system can rapidly compensate for measurable flow disturbances via feedforward, while simultaneously utilizing the high-speed feedback of the inner loop to directly correct internal heat distribution deviations based on the dynamic thermal field profile. This effectively suppresses disturbances before they propagate to the system outlet. Combined with unbalanced power distribution capabilities, it achieves rapid temperature response and effective overshoot suppression, thereby improving the overall dynamic control performance of the system. Attached Figure Description

[0032] Figure 1 This is a system architecture diagram of the present invention;

[0033] Figure 2 This is a flowchart of the method of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example:

[0036] Please see the appendix Figure 1 This invention provides a resistance-type steam superheating system and control method for precise temperature control, including:

[0037] The heating and sensing module includes a segmented self-sensing heating core arranged along the steam flow direction. The segmented self-sensing heating core includes multiple electrically independent heating sections. The heating sections are made of materials with preset resistance temperature coefficients. The heating and sensing module is used to heat the steam and provide physical signals reflecting its own temperature status.

[0038] In this embodiment, the basic component of the precisely temperature-controlled resistance steam superheating system is the heating and sensing module. This module, in terms of both physical structure and function, provides the necessary prerequisites for the overall system's state perception and precise control.

[0039] Specifically, the core of the heating and sensing module is a segmented self-sensing heating core. This core is physically arranged along the direction of steam flow in the pipeline, aiming to provide segmented and controllable heating of the flowing steam.

[0040] The segmented self-sensing heating core consists of multiple heating segments. These heating segments are electrically independent, meaning that each segment can be individually voltageed, current-driven, and its electrical parameters measured independently, thus avoiding electrical crosstalk between segments. Physically, these heating segments can be designed to be closely adjacent or integrally formed to ensure spatial continuity in heating the steam flow.

[0041] The key feature of this embodiment is that each heating section is made of a specific material with a preset, stable temperature coefficient of resistance. Specific grades of nickel-chromium alloys, iron-chromium-aluminum alloys, or other metals or alloys with significant and linear temperature coefficients of resistance can be used. This characteristic is the basis for achieving the self-sensing function, meaning that the resistance value of the heating section changes predictably and quantifiably with its own temperature.

[0042] The heating and sensing module has a dual function. Its primary function is to act as an actuator to heat the steam. When the external drive and measurement module applies the main heating power to it, its resistive material generates heat due to the Joule effect and transfers the heat to the steam through convection heat transfer.

[0043] The second, and core function of this invention, is to act as a distributed sensor array, providing a physical signal reflecting its real-time temperature state. Due to the aforementioned temperature coefficient of resistance characteristic, the real-time temperature of each heating segment during operation uniquely corresponds to a real-time resistance value. Therefore, by measuring this resistance value, the average temperature of the heating segment can be derived. This physical signal is the real-time dynamic resistance value of the heating segment.

[0044] It is worth noting that the heating and sensing functions are performed by the same physical entity, the heating section itself. This is fundamentally different from the existing technology where the heating element and temperature sensor are separate.

[0045] In this embodiment, the real-time temperature T of the i-th heating segment i (t) and its real-time dynamic resistance value R i The relationship between (t) can be precisely characterized by the following formula:

[0046]

[0047] Among them, T i (t) represents the real-time temperature of the i-th heating segment at time t; R i (t) represents the dynamic resistance value of the heating section measured at time t; T ref For calibration reference temperature; R i,ref For this heating section at the reference temperature T ref The reference resistance is pre-calibrated; α is the temperature coefficient of resistance of the material.

[0048] By combining the real-time temperature values ​​of all heating sections, a dynamic thermal field profile T can be constructed. profile (t). This profile presents a high-resolution snapshot of the temperature distribution along the steam flow direction in the form of a vector, transforming the unobservable internal thermodynamic processes in traditional control systems into physical states that can be quantified and monitored in real time and at high resolution.

[0049] Furthermore, the segmented structure of this heating and sensing module provides a physical basis for performing active thermal wave detection. In this application scenario, one or more upstream heating segments can be used as thermal wave excitation sources, actively generating thermal waves by applying small power perturbations. All the other downstream heating segments naturally form a distributed receiving array to capture the characteristic changes of the thermal wave as it propagates through the vapor medium, such as phase delay and amplitude attenuation.

[0050] This design allows subsequent processing and control modules to further identify key thermodynamic parameters of the system, such as the effective steam flow rate, based on the characteristics of heat wave propagation. The flow velocity can be estimated using the following formula:

[0051]

[0052] Among them, W tw Let Δφ be the angular frequency of the heat wave. ij For the heating segment S of the heat wave at two different locations i and S j The phase delay propagating between them, L ij This is the physical distance between the center points of the two heating sections.

[0053] In summary, the heating and sensing module in this embodiment, through its segmented structural design and the inherent physical properties of its materials, is no longer merely a heating actuator, but rather a composite functional unit integrating distributed temperature sensing and process detection. It provides subsequent control algorithms with unprecedented and abundant information about the real-time internal state of the system, thus laying the foundation for achieving precise temperature control that surpasses the performance of traditional control methods.

[0054] The drive and measurement module is electrically connected to the heating and sensing module. The drive and measurement module is used to: apply the main heating power to the heating section and simultaneously measure the real-time dynamic resistance value of the heating section as a physical signal.

[0055] In this embodiment, the drive and measurement module is a key component connecting the processing and control module and the heating and sensing module, providing the necessary hardware execution and data acquisition support for realizing the system's self-sensing function. This module establishes an independent electrical connection with each heating segment in the segmented self-sensing heating core.

[0056] Specifically, the core function of the drive and measurement module is that it is configured to simultaneously perform two seemingly conflicting tasks on the same physical conductor: apply a main heating power sufficient to cause a significant temperature rise, and simultaneously and independently measure the minute resistance change of the conductor caused by temperature changes.

[0057] To achieve this function, the driving and measurement module in this embodiment adopts a technical solution based on signal frequency domain separation. Each heating section within this module is equipped with an independent driving and measurement circuit.

[0058] Firstly, regarding the drive function, the module receives a power control signal from the processing and control module. This signal can be a digital quantity, such as the duty cycle of a pulse-width modulation signal or a power setpoint. The power drive unit within the drive and measurement module converts this control signal into the main heating power actually applied to the corresponding heating section. This main heating power is typically in DC or low-frequency AC form, and its energy is the primary source of steam temperature rise. Since each heating section is controlled by an independent drive unit, this provides the hardware execution basis for subsequently implementing an unbalanced power distribution strategy.

[0059] Secondly, regarding the measurement function, the module injects a probe AC ​​signal into the same heating section while applying the main heating power. This probe AC ​​signal has the characteristics of high frequency and low amplitude. The high frequency setting is to significantly separate it from the low-frequency or DC main heating power signal in the frequency domain, thereby avoiding spectral aliasing. The low amplitude setting is to ensure that the thermal effect generated by the probe signal itself is negligible and will not have a substantial impact on the main heating process and temperature field.

[0060] At the signal processing level, the drive and measurement module includes a sophisticated signal demodulation unit. This unit employs lock-in amplifier technology. When a composite current containing the main heating signal and the probe AC ​​signal flows through the heating section, the module simultaneously acquires the voltage across the heating section and the current flowing through it. The lock-in amplifier uses the frequency of the injected probe AC ​​signal as a reference frequency to perform phase-sensitive detection and low-pass filtering on the acquired composite signal.

[0061] In this way, the lock-in amplifier can accurately extract the voltage and current components that are in phase, frequency, and quadrature of the probed AC signal from an extremely noisy background overwhelmed by the powerful main heating signal. Based on these components, the complex impedance of the heating section at the probed frequency can be calculated with high precision. Since the heating section material is primarily resistive, the real part of its impedance is its real-time dynamic resistance value R. i (t).

[0062] This dynamic resistance value R i (t) is a clean measurement result, decoupled from the main heating power, and is transmitted to the processing and control module in real time. This value is directly and uniquely associated with the current average temperature of the heating section and is the source of all data for subsequent dynamic thermal profile reconstruction, online parameter identification, and closed-loop feedback control.

[0063] In summary, the drive and measurement module in this embodiment, through its unique dual-mode operating mechanism and frequency domain separation-based precision measurement method, successfully solves the technical challenge of detecting weak signals while injecting strong energy. It acts as an interface, transforming the abstract instructions of the upper-level control algorithm into heating behavior in the physical world, while simultaneously converting the temperature state of the physical world into a clean data stream that can be processed by the upper-level algorithm, thus forming a bridge connecting digital control and the physical process.

[0064] The processing and control module communicates with the drive and measurement module. The processing and control module is used for:

[0065] Based on the dynamic resistance value received from the drive and measurement module, and the temperature coefficient of resistance of the material, the real-time temperature of each heating section is calculated.

[0066] In this embodiment, the processing and control module serves as the core of the system's computation and decision-making, establishing a communication connection with the drive and measurement module. The primary and fundamental function of this module is to receive and process raw measurement data from the underlying hardware, transforming it into a precise description of the system's physical state.

[0067] Specifically, the processing and control module is configured to continuously receive data streams from the drive and measurement module at a high sampling rate. This data stream contains the real-time dynamic resistance value R of each independent heating segment in the segmented self-sensing heating core at a given moment. i (t).

[0068] Upon receiving the dynamic resistance value, the processing and control module performs a crucial calculation operation: converting this electrical measurement into a thermodynamic temperature value. This conversion is not a simple estimation but is based on a pre-established, precise physical model. The module internally stores the material physical property parameters for each heating section, among which the crucial parameters are the material's temperature coefficient of resistance α and the resistance at a specific reference temperature T. ref The reference resistance value R is pre-calibrated precisely. i,ref .

[0069] The processing and control module processes each heating section S i Perform an independent temperature calculation. This calculation follows the established mathematical formula:

[0070]

[0071] In this formula:

[0072] T i (t) represents the real-time average temperature of the i-th heating segment at time t, calculated by the processing and control module.

[0073] Ri (t) is the real-time dynamic resistance value of the heating section received by the module from the drive and measurement module at time t;

[0074] T ref The known stable temperature at which the reference resistor is calibrated;

[0075] R i,ref For the i-th heating segment at the reference temperature T ref The reference resistance value is used as the reference point for calculation.

[0076] α is the inherent, known temperature coefficient of resistance of the heating section material.

[0077] By repeatedly performing the above calculations for each heating segment in the segmented self-sensing heating core, the processing and control module is able to obtain a set of discrete data points representing the current temperature of all heating segments in each control cycle.

[0078] The realization of this function is the cornerstone of the entire self-sensing control scheme. It transforms previously unobservable, distributed physical quantities into quantified digital signals that can be directly utilized by advanced algorithms through precise measurement of electrical quantities and solution of physical property models. The calculation result, namely the real-time temperature of each heating segment, is the data input source for all subsequent advanced functions such as dynamic thermal field profile reconstruction, system state analysis, fault diagnosis, and closed-loop feedback control.

[0079] Based on the real-time temperature of each heating segment, a dynamic thermal field profile characterizing the temperature distribution along the segmented self-sensing heating core is reconstructed.

[0080] In this embodiment, after calculating the real-time temperature of each independent heating segment, the processing and control module further performs a crucial data integration and state characterization task. This task aims to transform discrete, multi-point temperature information into a holistic description that comprehensively and intuitively reflects the internal thermodynamic state of the system.

[0081] Specifically, the processing and control module is configured to process the real-time temperature values ​​T1(t), T2(t), ..., T of the N heating segments located at different physical locations obtained in the previous calculation step. N (t) is organized and integrated in an orderly manner according to its physical arrangement in the segmented self-sensing heating core.

[0082] In terms of data structure, this integration process is represented by constructing a one-dimensional column vector. This vector at any time t is defined as the dynamic thermal field profile T. profile (t), whose mathematical expression is as follows:

[0083] T profile(t)=[T1(t),T2(t),…,T N (t)] T ;

[0084] In this vector:

[0085] T profile (t) is the dynamic thermal field profile reconstructed at time t;

[0086] Each element T of the vector i (t) all correspond to the real-time average temperature of the i-th heating section along the steam flow direction at that moment;

[0087] The dimension N of the vector is equal to the number of physical segments of the segmented self-sensing heating core.

[0088] The significance of constructing this dynamic thermal profile lies in transforming the originally independent, scalar temperature readings into vectorized system state variables capable of characterizing spatial distribution properties. This fundamentally differs from existing technologies that rely solely on a single outlet temperature sensor. A single sensing point can only provide delayed, spatially averaged scalar information, while the dynamic thermal profile in this embodiment provides an instantaneous snapshot of the temperature distribution along the system's internal path.

[0089] By continuously reconstructing this dynamic thermal field profile, the processing and control module can observe, with extremely high temporal resolution, the propagation process of thermal energy within the heating core as it flows with steam, the formation and evolution of temperature gradients, and the dynamic impact of external disturbances on the internal temperature field.

[0090] Once reconstructed, this dynamic thermal profile is no longer a simple list of raw data, but rather serves as core, structured information that directly supports subsequent, higher-level control decisions. For example, in the subsequent inner-loop profile control layer, this T... profile (t) will be the controlled object, and compared with the preset optimal thermal field profile T, which represents the optimal heating process. profile,ideal Direct vector comparisons are performed to calculate the control law for rapidly stabilizing the internal thermal processes.

[0091] In summary, the process of reconstructing the dynamic thermal field profile is a key transitional step in this embodiment, enabling the transition from basic sensing to advanced control. It transforms low-level, discrete physical measurements into an information-rich system state representation that can be directly utilized by modern control theory, providing the necessary data foundation for achieving refined and proactive control of the entire heating process, not just the final outlet temperature.

[0092] Based on the dynamic thermal field profile, a power control signal is generated and output to the drive and measurement module to control the main heating power;

[0093] In this embodiment, after reconstructing a dynamic thermal profile that accurately characterizes the internal state of the system, the core task of the processing and control module shifts to making control decisions based on this information and ultimately generating executable power control commands. This process aims to adjust the main heating power to an appropriate level to drive the system to reach and maintain a preset temperature target.

[0094] Specifically, the processing and control module employs a layered, decoupled composite control strategy that integrates multiple control concepts to generate and output power control signals. This strategy is not a single feedback loop, but rather decomposes the complex control task into multiple collaborative layers to address different control requirements.

[0095] First, the strategy includes a feedforward control layer. This layer's function is to provide predictive open-loop compensation for the most significant, directly measurable disturbance in the system: the inlet steam flow rate. The processing and control module receives the real-time mass flow rate signal m from the flow meter located at the system inlet. steam (t). Based on the fundamental principle of steady-state thermal balance, this layer pre-calculates the basic total power P required to cope with the current flow rate change. ff (t):

[0096] P ff (t)=m steam (t)·C p,steam ·(T set -T in );

[0097] Among them, C p,steam T is the specific heat capacity of steam at constant pressure. set For the final target steam outlet temperature, T in This refers to the inlet temperature of the steam.

[0098] Building upon this, the control strategy includes an inner-loop profile control layer, which is its core innovation. Unlike traditional control methods that only focus on the final outlet temperature, the direct control objective of this layer is the vectorized dynamic thermal field profile T reconstructed in the aforementioned steps. profile (t). The processing and control module internally stores a preset optimal thermal field profile T. profile,ideal This optimal profile represents the most ideal temperature distribution along the path under specific operating conditions. The inner ring profile control layer calculates the vector error E between the current dynamic thermal field profile and this optimal thermal field profile in real time. profile (t):

[0099] E profile (t)=T profile,ideal -T profile (t);

[0100] Based on this vector error, this layer uses the scaling gain matrix K p,inner Calculate the power adjustment vector ΔP inner (t). Each component of this vector corresponds to a power fine-tuning amount in the heating section, the purpose of which is to quickly suppress any local deviations in the internal heat distribution and eliminate them before the disturbance propagates to the outlet.

[0101] To ensure the steady-state accuracy of the final control, the control strategy also includes an outer-loop setpoint tracking layer. This layer employs a conventional proportional-integral-derivative (PID) controller, whose input is the actual temperature T measured by a temperature sensor located at the system's total output. out (t) and the final target temperature T set scalar error e between out (t). This layer is used to eliminate any long-term steady-state errors caused by model mismatch or unmeasured perturbations, and outputs the overall corrected power P. outer (t).

[0102] Finally, the processing and control module performs power fusion and allocation. It first adds the outputs of the feedforward control layer and the outer loop setpoint tracking layer to obtain the required base total power P at the current moment. total (t)=P ff (t)+P outer (t). Subsequently, the module does not distribute this total power evenly, but instead uses a preset reference power distribution coefficient vector β, combined with the dynamic adjustment amount ΔP calculated by the inner ring profile control layer. inner (t), performing unbalanced power distribution. The final power vector P(t) applied to each heating section is determined by the following equation:

[0103] P(t) = β·P total (t)+ΔP inner (t);

[0104] The processing and control module uses this calculated power vector P(t) as the final power control signal and outputs it to the drive and measurement module via the communication interface. Based on this instruction, the drive and measurement module applies precise main heating power to each heating section, thus completing the entire control closed loop.

[0105] Please see the appendix Figure 2 Another embodiment of the invention provides a method for precisely controlling the temperature of resistance-type steam superheating, comprising the following steps:

[0106] S1. Using the drive and measurement module, the dynamic resistance value of each heating segment in the segmented self-sensing heating core is measured in real time.

[0107] S2. Based on the measured dynamic resistance value and the temperature coefficient of resistance of the heating section material, the temperature of each heating section is calculated in real time, thereby reconstructing the dynamic thermal field profile.

[0108] S3. Based on the comparison results between the dynamic thermal field profile and the target control state, generate and distribute power control signals to each heating section.

[0109] The method in this embodiment can be used to execute the above system embodiment, and its principle and technical effect are similar, so it will not be described again here.

[0110] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A resistance-type steam superheating system with precise temperature control, characterized in that, include: The heating and sensing module includes a segmented self-sensing heating core arranged along the steam flow direction. The segmented self-sensing heating core includes multiple electrically independent heating sections. The heating sections are made of a material with a preset temperature coefficient of resistance. The heating and sensing module is used to heat the steam and provide physical signals reflecting its own temperature state. The driving and measurement module is electrically connected to the heating and sensing module. The driving and measurement module is used to: apply the main heating power to the heating section and simultaneously measure the real-time dynamic resistance value of the heating section as the physical signal. The processing and control module is communicatively connected to the drive and measurement module, and the processing and control module is used for: Based on the dynamic resistance value received from the drive and measurement module and the temperature coefficient of resistance of the material, the real-time temperature of each heating section is calculated. Based on the real-time temperature of each heating segment, a dynamic thermal field profile characterizing the temperature distribution along the segmented self-sensing heating core is reconstructed. Based on the dynamic thermal field profile, a power control signal is generated and output to the drive and measurement module to control the main heating power.

2. The resistance-type steam superheating system with precise temperature control according to claim 1, characterized in that, The processing and control module is also configured to perform active thermal wave detection to identify system thermodynamic parameters online, the active thermal wave detection including: The drive and measurement module is controlled to superimpose a preset power disturbance onto the main heating power applied to the upstream heating section to form a heat wave; The propagation characteristics of the heat wave are obtained by monitoring the temperature response of other downstream heating sections. Based on the propagation characteristics of the heat wave, at least one thermodynamic parameter of the system is identified.

3. The precise temperature-controlled resistance steam superheating system according to claim 2, characterized in that, The propagation characteristics of the heat wave include the phase delay between any two heating sections, and the thermodynamic parameter is the effective steam velocity. The processing and control module calculates the effective steam velocity using the following formula. in, The effective flow rate of the steam; Δφ ij The heat wave in the heating section S, which is the upstream segment. i With the heating section S as the downstream section j Phase delay propagation between them; W tw The angular frequency of the heat wave; L ij The heating section S i From the center to the heating section S j The physical distance between the centers.

4. The resistance-type steam superheating system with precise temperature control according to claim 1, characterized in that, The processing and control module is configured to generate the power control signal using a hierarchical control strategy, the hierarchical control strategy including: The inner ring profile control layer is used to maintain the dynamic thermal field profile at a preset optimal thermal field profile. The outer loop setpoint tracking layer is used to adjust based on the deviation between the actual temperature at the system's total outlet and the final target temperature.

5. The resistance-type steam superheating system with precise temperature control according to claim 4, characterized in that, The inner ring profile control layer generates a power adjustment amount by calculating the vector error between the dynamic thermal field profile and the optimal thermal field profile, wherein the vector error E profile The formula for calculating (t) is: E profile (t)=T profile,ideal -T profile (t); in, E profile (t) represents the vector error at time t; T profile,ideal This is the preset optimal thermal field profile; T profile (t) is the dynamic thermal field profile at time t.

6. The resistance-type steam superheating system with precise temperature control according to claim 4, characterized in that, The hierarchical control strategy also includes a feedforward control layer, which is used to pre-calculate the compensatory main heating power based on the real-time changes in the steam flow rate at the system inlet.

7. The resistance-type steam superheating system with precise temperature control according to claim 1, characterized in that, The processing and control module is configured to perform unbalanced power distribution on the multiple heating sections based on the power control signal, so as to actively adjust the shape of the dynamic thermal field profile.

8. The resistance-type steam superheating system with precise temperature control according to claim 1, characterized in that, The drive and measurement module measures the dynamic resistance value by superimposing a high-frequency, low-amplitude detection AC signal onto the main heating power and using a lock-in amplifier for demodulation.

9. The resistance-type steam superheating system with precise temperature control according to claim 1, characterized in that, Also includes: A flow meter installed at the steam inlet; A temperature sensor is installed at the main steam outlet; wherein, the processing and control module uses the measurement signals from the flow meter and the temperature sensor for feedforward control and outer loop setpoint tracking control, respectively.

10. A method for controlling the precise temperature of a resistance-type superheated steam system, according to any one of claims 1-9, comprising the following steps: S1. Using the driving and measurement module, measure the dynamic resistance value of each heating segment in the segmented self-sensing heating core in real time; S2. Based on the measured dynamic resistance value and the temperature coefficient of resistance of the heating section material, the temperature of each heating section is calculated in real time, thereby reconstructing the dynamic thermal field profile. S3. Based on the comparison results between the dynamic thermal field profile and the target control state, generate and distribute power control signals to each of the heating sections.

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