Energy-saving brazing furnace heating process temperature self-adaptive control method and system

Abstract

This application relates to the field of industrial furnace temperature control technology, and discloses an energy-saving brazing furnace heating process temperature adaptive control method and system. The heating process of the brazing furnace is divided into at least three continuous temperature ranges, including a first temperature range, a second temperature range, and a transition temperature range. A first power control strategy and a first temperature fluctuation tolerance are configured for the first temperature range, and a second power control strategy and a second temperature fluctuation tolerance are configured for the second temperature range. The current temperature range of the brazing furnace is determined based on the current temperature. When it is determined that the brazing furnace is currently in the first temperature range, the first power control strategy is executed to output heating power, ensuring that the characteristic temperature is within the first temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the second temperature range, the second power control strategy is executed to output heating power, ensuring that the characteristic temperature is within the second temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the transition temperature range, a smooth switching logic is executed.

Description

Technical Field

[0001] This application relates to the field of industrial furnace temperature control technology, and more specifically, to an energy-saving brazing furnace heating process temperature adaptive control method and system. Background Technology

[0002] In industrial brazing production, temperature control of the brazing furnace is a crucial factor determining product quality and production costs. The heating process must not only ensure the workpiece reaches a precise and stable brazing temperature to form a high-quality weld, but also meet stringent energy-saving requirements. However, in actual production scenarios, especially in mixed-line production models handling different materials, batches, and loads, these two objectives often conflict. For example, in the initial heating stage, the control system may need to output a large power to rapidly raise the temperature, which contradicts the energy-saving goal; while in the holding stage near the target temperature, the system needs frequent power adjustments for precise temperature control, which may increase energy consumption due to over-response. Existing control methods typically employ a fixed set of control logic to handle the entire heating process, lacking the ability to adapt to the main contradictions at different stages. When furnace conditions change, such as changes in furnace atmosphere flow leading to variations in heat transfer efficiency, or differences in workpiece load causing variations in heat capacity, this fixed control strategy struggles to balance both objectives, often resulting in a dilemma: either sacrificing energy consumption to ensure temperature stability, or allowing temperature fluctuations to exceed process tolerances in pursuit of energy saving. The rigidity of this control strategy causes the control system to oscillate between energy saving and temperature stability, potentially leading to excessive temperature fluctuations and energy consumption, thus affecting product qualification rates and production economics. To address these issues, existing technologies urgently need improvement. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this application provides an energy-saving brazing furnace heating process temperature adaptive control method and system, which can solve the technical problem that in the existing brazing furnace temperature control, it is difficult to simultaneously achieve the energy-saving target and the temperature stability target, resulting in a rigid control strategy and poor process adaptability.

[0004] In a first aspect, this application provides an energy-saving brazing furnace heating process temperature adaptive control method, including: The heating process of the brazing furnace is divided into at least three consecutive temperature ranges, including a first temperature range, a second temperature range following the first temperature range, and a transition temperature range from the first temperature range to the second temperature range. A first power control strategy and a first temperature fluctuation tolerance are configured for a first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and a second power control strategy and a second temperature fluctuation tolerance are configured for a second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is smaller than the first temperature fluctuation tolerance. The current temperature of the brazing furnace is obtained in real time, and the current temperature range of the brazing furnace is determined based on the current temperature. When it is determined that the brazing furnace is currently in the first temperature range, the first power control strategy is executed to output heating power so that the characteristic temperature is within the first temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the second temperature range, the second power control strategy is executed to output heating power so that the characteristic temperature is within the second temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the transition temperature range, the smooth switching logic is executed, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

[0005] This technical solution divides the entire heating process into zones based on the core control objectives of different stages, and matches them with corresponding control strategies and tolerances. This allows the control system to focus on energy saving in the early stages of heating, and on high-precision temperature stabilization in the critical stage approaching the brazing temperature. The strategy is seamlessly switched through a smooth transition, which fundamentally solves the conflict between the two major objectives of energy saving and temperature stabilization, and achieves adaptive optimization control throughout the entire process.

[0006] Furthermore, the steps of acquiring the current temperature of the brazing furnace in real time and determining the current temperature range of the brazing furnace based on the current temperature include: Acquire real-time temperature data from multiple temperature measurement points distributed within the brazing furnace; The average temperature value is obtained by averaging the real-time temperature data from multiple temperature measurement points and used as the current temperature. The average temperature value is compared with the preset interval switching threshold to determine the current temperature range of the brazing furnace.

[0007] This technical solution uses multi-point temperature measurement and average value to characterize the current temperature inside the furnace, effectively overcoming the measurement errors that may be caused by single-point temperature measurement due to position deviation or local temperature anomalies. This results in a more comprehensive and accurate acquisition of the furnace temperature status, providing a reliable data foundation for subsequent interval judgment and strategy switching, and improving the robustness of control.

[0008] Furthermore, the step of executing the first power control strategy to output heating power includes: Obtain the real-time characteristic temperature rise rate of the brazing furnace; If the real-time characteristic temperature rise rate is within the preset reference rate range, then maintain the current heating power output; If the real-time characteristic temperature rise rate is not within the preset reference rate range, the heating power will be finely adjusted in steps according to the degree of deviation of the real-time characteristic temperature rise rate, with a preset adjustment frequency and adjustment range.

[0009] This technical solution focuses on the heating rate rather than the absolute temperature value as the control target within the first temperature range where energy saving is prioritized. It maintains an economical heating slope through gentle, step-by-step power fine-tuning, avoiding large power fluctuations and energy waste caused by pursuing rapid response, and minimizing energy consumption while meeting basic heating requirements.

[0010] Furthermore, the steps for implementing the second power control strategy to output heating power include: Calculate the temperature deviation between the current temperature and the preset target temperature in real time; When the temperature deviation exceeds the second temperature fluctuation tolerance, the power compensation amount is calculated based on the temperature deviation and the preset proportional coefficient. The heating power is adjusted in real time according to the power compensation amount so that the temperature deviation value returns to the second temperature fluctuation tolerance.

[0011] This technical solution employs a proportional control logic based on temperature deviation within the second temperature range, where temperature stability is extremely critical. This logic enables a rapid and precise response to any minute changes deviating from the target temperature. By directly correcting the heating power through the calculated power compensation, the furnace temperature is strictly locked within a very small fluctuation tolerance, thereby ensuring the process quality of the critical brazing stage.

[0012] Furthermore, the steps for calculating the power compensation amount based on the temperature deviation value and the preset proportional coefficient include: Obtain the preset scaling factor; Real-time acquisition of environmental media parameters inside the brazing furnace, including at least one of pressure information and flow information; Assess whether the heat transfer efficiency in the brazing furnace has deviated based on environmental medium parameters; If the heat transfer efficiency deviates, the preset proportional coefficient is corrected according to the change range of the environmental medium parameters to obtain the corrected proportional coefficient, and the corrected proportional coefficient is used as the effective proportional coefficient; otherwise, the preset proportional coefficient is used as the effective proportional coefficient. The power compensation is calculated based on the temperature deviation value and the effective proportionality coefficient.

[0013] This technical solution introduces the monitoring of environmental medium parameters within the furnace and dynamically adjusts control parameters accordingly. This allows the control system to proactively adapt to changes in heat transfer efficiency caused by factors such as variations in the furnace atmosphere. This feedforward compensation mechanism enhances the disturbance rejection capability of the second power control strategy, maintaining precise temperature control even when operating conditions fluctuate, thus avoiding the lag and overshoot inherent in relying solely on feedback control.

[0014] Furthermore, the steps to reduce the current temperature fluctuation tolerance include: Determine the end temperature of the first temperature range and the start temperature of the second temperature range. The tolerance shrinkage factor is calculated based on the linear ratio between the current temperature at the end of the first temperature range and the starting temperature of the second temperature range. The difference between the first temperature fluctuation tolerance and the second temperature fluctuation tolerance is weighted using a tolerance shrinkage coefficient so that the current temperature fluctuation tolerance decreases linearly from the first temperature fluctuation tolerance to the second temperature fluctuation tolerance.

[0015] This technical solution gradually tightens the temperature fluctuation tolerance from loose to strict within the transition temperature range, avoiding control system oscillations that may be caused by abrupt changes in tolerance. This progressive constraint strengthening guides the control system to gradually adapt to more precise control requirements, preparing it for the high-stability control stage in the second temperature range and ensuring the smoothness of the control process.

[0016] Furthermore, steps to increase the weight of temperature stability in current power control strategies include: Obtain the first power output value of the first power control strategy and the second power output value generated by the second power control strategy; The final heating power is obtained by calculating the weighted average of the first power output value and the second power output value. As the current temperature rises within the transition temperature range, the weight of the first power output value is gradually reduced, while the weight of the second power output value is gradually increased.

[0017] This technical solution achieves a flexible transition in control logic from energy saving priority to stability priority by dynamically weighting and fusing the outputs of two different strategies. The change in power output is continuous and smooth, avoiding the power surges and furnace temperature shocks that may occur when the two strategies are switched abruptly, thus ensuring the continuity and stability of the entire heating curve.

[0018] Further, after the step of calculating the weighted average of the first power output value and the second power output value to obtain the final heating power, the following steps are included: Real-time monitoring of the instantaneous output deviation between the first power output value and the second power output value; If the instantaneous output deviation exceeds the preset strategy conflict threshold, the maximum allowable range of a single heating power adjustment is dynamically adjusted according to the magnitude of the instantaneous output deviation, and the heating power is smoothly switched from the current heating power to the final heating power based on the maximum allowable range of a single heating power adjustment; otherwise, the heating power is smoothly switched from the current heating power to the final heating power based on the preset adjustment range.

[0019] This technical solution establishes a safety valve to monitor the degree of conflict between the two strategies. When the power recommendations given by the energy-saving strategy and the stability strategy differ too much, the conflict is mitigated by limiting the step size of the power adjustment. This effectively prevents drastic fluctuations in the control output caused by large differences in strategy objectives, further enhancing the smoothness and reliability of the transition process.

[0020] Furthermore, during the execution of the smooth switching logic, the method also includes: The temperature difference between multiple temperature measuring points distributed in the brazing furnace is compared in real time. If the maximum temperature difference among the multiple temperature measuring points is greater than or equal to the preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is suspended, and differentiated heating power compensation is performed on the area corresponding to the multiple temperature measuring points to reduce the maximum temperature difference. When the maximum temperature difference decreases to less than the preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is resumed.

[0021] This technical solution introduces the assessment of furnace temperature uniformity during critical strategy switching periods, ensuring that the temperature throughout the furnace is balanced before entering the high-precision temperature control stage. This logic of balancing first and then fine-tuning avoids entering the heat preservation stage with a large internal temperature difference, effectively preventing welding defects caused by uneven heating of the workpiece and significantly improving the overall quality of the final product.

[0022] Secondly, this application also discloses an energy-saving brazing furnace heating process temperature adaptive control system for executing the energy-saving brazing furnace heating process temperature adaptive control method as described in any of the preceding claims, the system comprising: The interval division module is used to divide the heating process of the brazing furnace into at least three continuous temperature intervals, including a first temperature interval, a second temperature interval following the first temperature interval, and a transition temperature interval from the first temperature interval to the first temperature interval. The strategy configuration module is used to configure a first power control strategy and a first temperature fluctuation tolerance for a first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and to configure a second power control strategy and a second temperature fluctuation tolerance for a second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is less than the first temperature fluctuation tolerance. The interval determination module is used to obtain the current temperature of the brazing furnace in real time and determine the current temperature interval of the brazing furnace based on the current temperature. The strategy execution module is used to execute a first power control strategy to output heating power when it is determined that the brazing furnace is currently in a first temperature range, so that the characteristic temperature fluctuation is within the first temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in a second temperature range, it executes a second power control strategy to output heating power, so that the characteristic temperature fluctuation is within the second temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in a transition temperature range, it executes a smooth switching logic, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

[0023] This application creatively divides the heating process of the brazing furnace into a first temperature zone for energy saving, a second temperature zone for temperature stability, and a transition temperature zone for smooth transition, and configures differentiated control strategies and tolerances for each zone, thereby bringing significant beneficial effects. Compared to the problem of conflict between energy saving and temperature stability objectives caused by the use of a single fixed control strategy in existing technologies, this application sets clear and unique optimization objectives for different heating stages through the concept of zoned control. In the initial stage of heating, the system implements a power strategy focused on limiting energy consumption at the expense of a relaxed temperature tolerance, effectively reducing energy consumption in non-critical stages. In the critical stage, approaching and reaching the brazing temperature, the system switches to a strategy focused on high-precision temperature stability, coupled with a stricter temperature tolerance, ensuring the final welding quality of the product. More importantly, by setting a transition interval between the two intervals and implementing logic including tolerance contraction and smooth switching of strategy weights, this application ensures that the transition from one control mode to another is gradual and shock-free. This effectively avoids system oscillations and temperature overshoot that may be caused by sudden changes in control parameters, guaranteeing the stability and controllability of the entire heating process. In summary, this application not only fundamentally solves the contradiction between energy saving and temperature stability, achieving a dynamic balance and synergistic optimization of the two throughout the entire process, but also significantly improves the adaptability and robustness of the control system to different operating conditions, ultimately achieving the dual goals of reducing production costs and ensuring product quality. Attached Figure Description

[0024] Figure 1This is a flowchart illustrating an energy-saving brazing furnace temperature adaptive control method provided in an embodiment of this application.

[0025] Figure 2 This is a schematic diagram of the structure of an energy-saving brazing furnace heating process temperature adaptive control system provided in an embodiment of this application.

[0026] Labeling Explanation: 210, Interval Division Module; 220, Strategy Configuration Module; 230, Interval Judgment Module; 240, Strategy Execution Module. Detailed Implementation

[0027] The technical solutions of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. The components of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0028] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] In modern precision manufacturing, brazing of metal components is a crucial process. The quality of the brazing directly determines the reliability and lifespan of the final product. In a brazing workshop with mixed production lines, the same vacuum brazing furnace needs to process multiple batches of workpieces within a single day. For example, in the morning, a batch of high-value titanium alloy turbine blades needs to be processed, requiring extremely stringent uniformity and stability of the brazing temperature; any temperature fluctuations outside the process window can lead to component scrap. In the afternoon, a batch of cost-sensitive standard stainless steel joints needs to be processed, where quality requirements are only within acceptable limits, but the manufacturer is more concerned with reducing the electric heating energy consumption per unit to control costs. Existing brazing furnace control systems typically employ a fixed heating strategy. If a high-precision, forceful control strategy is used to ensure the quality of the turbine blades, unnecessary energy waste occurs when heating the stainless steel joints; conversely, if a milder control strategy is used for energy saving, it is difficult to suppress temperature fluctuations when heating the turbine blades, posing a significant quality risk. This rigidity in the control strategy forces the production process to make difficult trade-offs between quality and cost, making it impossible to achieve a balance and optimization of both.

[0030] Regarding this, firstly, see... Figure 1 This application provides an energy-saving brazing furnace heating process temperature adaptive control method, the method comprising: S1. The heating process of the brazing furnace is divided into at least three consecutive temperature ranges, including a first temperature range, a second temperature range following the first temperature range, and a transition temperature range from the first temperature range to the second temperature range. S2. Configure a first power control strategy and a first temperature fluctuation tolerance for the first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and configure a second power control strategy and a second temperature fluctuation tolerance for the second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is smaller than the first temperature fluctuation tolerance. S3. Obtain the current temperature of the brazing furnace in real time, and determine the current temperature range of the brazing furnace based on the current temperature. S4. When it is determined that the brazing furnace is currently in the first temperature range, the first power control strategy is executed to output heating power so that the characteristic temperature is within the first temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the second temperature range, the second power control strategy is executed to output heating power so that the characteristic temperature is within the second temperature fluctuation tolerance. When it is determined that the brazing furnace is currently in the transition temperature range, the smooth switching logic is executed, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

[0031] The first temperature range refers to a relatively long heating phase from the start of the heating process to near the critical process temperature. In this range, the core task is to increase the overall furnace temperature; the precision requirements for temperature control are relatively low. However, due to the long duration and large total heating volume, this phase represents the main potential for energy saving and consumption reduction. The second temperature range refers to the critical process window immediately adjacent to the melting point or solidus temperature of the brazing material. In this range, any slight temperature fluctuation can affect the wetting, spreading, and final weld quality of the brazing filler metal. Therefore, the core task of control is to achieve extremely high temperature stability, ensuring that the temperature is precisely maintained near the target value. The transition temperature range serves as a bridge connecting the two ranges. Within this range, the control system needs to prepare for the upcoming high-precision control phase, gradually tightening the control constraints and smoothly transitioning to the control objective.

[0032] The first power control strategy is an economy-oriented control method that minimizes drastic power adjustments and peak output while ensuring basic heating tasks are met, thereby reducing total energy consumption. The second power control strategy is a quality-oriented control method that, at the cost of higher energy consumption, rapidly and forcefully corrects any deviations from the target temperature to ensure high temperature stability. Temperature fluctuation tolerance refers to the allowable deviation between the current temperature and the ideal temperature within a specific temperature range. A larger first temperature fluctuation tolerance means the system has a high tolerance for temperature fluctuations; a smaller second temperature fluctuation tolerance means extremely stringent temperature control is required. Smooth switching logic is used to achieve a gradual and seamless transition of control strategy and parameters from the first range to the second range within the transition temperature range.

[0033] The above method will be described in detail below with reference to a specific embodiment. Assume a vacuum brazing furnace needs to braze a batch of stainless steel components for precision medical devices, with a target brazing temperature of 1050 degrees Celsius. According to process requirements, the entire heating process is divided into three zones: the first temperature zone is from room temperature to 900 degrees Celsius; the transition temperature zone is from 900 degrees Celsius to 1030 degrees Celsius; and the second temperature zone is from 1030 degrees Celsius to 1060 degrees Celsius, which includes the target holding point of 1050 degrees Celsius.

[0034] During the process parameter setting phase, operators configure different control parameters for the three temperature ranges through a human-machine interface. The first temperature fluctuation tolerance configured for the first temperature range is ±10 degrees Celsius, meaning that below 900 degrees Celsius, as long as the actual temperature differs from the preset heating curve by no more than 10 degrees Celsius, the control system considers it within the normal range. Simultaneously, the first power control strategy configured for this range is a coarse-adjustment control based on the heating rate. The second temperature fluctuation tolerance configured for the second temperature range is extremely stringent, ±1.5 degrees Celsius, to ensure brazing quality. The second power control strategy configured for this range is a precision proportional-integral-derivative control based on temperature deviation.

[0035] Once the heating process begins, the control system, such as an industrial computer with an embedded control program, starts to acquire the current temperature of the brazing furnace in real time and determines its current temperature range.

[0036] When the furnace temperature is below 900 degrees Celsius, the system determines that it is currently in the first temperature range. At this time, the strategy execution module invokes the first power control strategy. The core of this strategy is not to focus on the absolute value of the temperature, but rather on the economic efficiency of temperature rise. For example, it may adjust the output power of the heater at a low frequency (e.g., once per minute), and the magnitude of each adjustment is also limited, avoiding frequent activation of high power output to catch up with small temperature differences. This ensures the overall temperature rise trend while significantly reducing energy consumption. The furnace temperature curve may fluctuate slightly during this stage, but it always remains within a tolerance range of ±10 degrees Celsius.

[0037] As the furnace temperature rises and enters the transition temperature range of 900°C to 1030°C, the smooth switching logic is activated. On one hand, the temperature fluctuation tolerance begins to dynamically shrink, no longer a fixed ±10°C, but decreasing linearly with increasing temperature. When the temperature reaches 1030°C, the tolerance smoothly converges to ±1.5°C. On the other hand, the heating power output is no longer determined by a single strategy, but by the combined effect of the first and second power control strategies. Specifically, the final power output is a weighted average of the suggested power calculated by the two strategies. At 900°C, the weight of the first power control strategy may be as high as 0.9, and the weight of the second power control strategy is 0.1; as the temperature rises, the weight of the former gradually decreases, and the weight of the latter gradually increases. When the temperature reaches 1030°C, the weight of the first power control strategy drops to 0, and the weight of the second power control strategy rises to 1.0. This gradual switching avoids the impact on the system caused by sudden changes in the control target.

[0038] Once the furnace temperature reaches the second temperature range of 1030 degrees Celsius, control is completely handed over to the second power control strategy. At this point, the control system monitors the temperature deviation at an extremely high frequency, such as several times per second, and makes rapid and subtle adjustments to the heating power based on a precise control algorithm, firmly locking the furnace temperature within ±1.5 degrees Celsius of the target point of 1050 degrees Celsius until the brazing process is completed.

[0039] This zoned, adaptive control method achieves global optimization of the entire heating process. It maximizes energy savings in the early, non-critical stages; ensures product quality during the critical brazing stage; and guarantees stability and reliability throughout the process through a smooth transition, perfectly resolving the inherent contradiction between energy saving and temperature stability in traditional control methods.

[0040] Furthermore, the steps of acquiring the current temperature of the brazing furnace in real time and determining the current temperature range of the brazing furnace based on the current temperature include: Acquire real-time temperature data from multiple temperature measurement points distributed within the brazing furnace; The average temperature value is obtained by averaging the real-time temperature data from multiple temperature measurement points and used as the current temperature. The average temperature value is compared with the preset interval switching threshold to determine the current temperature range of the brazing furnace.

[0041] During the heating phase, the temperature in areas closer to the heating element will be higher than in areas farther away, and the heating conditions of the workpiece also vary at different locations. If only data from a single temperature measurement point is relied upon, the data may not be representative, potentially causing the control system to determine the interval switching too early or too late, thus affecting the control effect.

[0042] In one specific implementation, five armored K-type thermocouples are installed at the top, middle, and bottom positions along the diagonal direction inside the brazing furnace, as well as at the center of the furnace door and bottom. The control system's data acquisition card polls these five thermocouples twice per second to obtain their real-time temperature readings. Before averaging, the system performs a simple validity check. For example, if a reading experiences a jump far exceeding physical probability within a short period, or if its difference from the other four readings exceeds a preset large threshold, such as 50 degrees Celsius, the reading may be considered an outlier and temporarily discarded to prevent sensor malfunction from interfering with the calculation. Subsequently, the system adds all valid readings and divides by the number of valid sensors to obtain an average temperature value that reflects the average thermodynamic state of the entire furnace. For example, at a certain moment, the readings of the five thermocouples are 851, 855, 849, 852, and 853 degrees Celsius, and the calculated average temperature value is 852 degrees Celsius. The control system uses this average temperature of 852 degrees Celsius to compare with preset interval switching thresholds such as 900 degrees Celsius and 1030 degrees Celsius to determine which temperature interval it is currently in. This method of obtaining the current temperature greatly reduces the limitations and random errors of a single measuring point, making the interval determination more reliable and robust.

[0043] Specifically, within the first temperature range where energy saving is prioritized, the steps for implementing the first power control strategy to output heating power include: Obtain the real-time characteristic temperature rise rate of the brazing furnace; If the real-time characteristic temperature rise rate is within the preset reference rate range, then maintain the current heating power output; If the real-time characteristic temperature rise rate is not within the preset reference rate range, the heating power will be finely adjusted in steps according to the degree of deviation of the real-time characteristic temperature rise rate, with a preset adjustment frequency and adjustment range.

[0044] In the brazing example of the aforementioned medical device components, the process engineer, based on experience and experimental data, set an economical reference rate range for temperature rise, such as 12 to 15 degrees Celsius per minute. When the control system operates within this first temperature range, it continuously calculates the rate of increase of the current average temperature (i.e., the real-time characteristic temperature). This rate can be obtained by linearly fitting the temperature over a certain time window, such as 30 seconds, to obtain the slope, or simply by subtracting the temperature from 30 seconds ago from the current temperature and then performing the calculation.

[0045] Suppose that at a certain moment, the system calculates a heating rate of 13.5 degrees Celsius per minute, which falls within the preset reference rate range. In this case, even if the current temperature is 3 degrees Celsius lower than the ideal heating curve, the first power control strategy will determine that everything is normal and instruct the power regulator to maintain the current heating power output. This laissez-faire approach avoids unnecessary power adjustments.

[0046] Let's assume that due to the larger load of the new batch of workpieces, the increased heat capacity causes the heating rate to slow to 9 degrees Celsius per minute, below the lower limit of the reference range. In this case, the control system will initiate a fine-tuning program. Instead of drastically increasing the power all at once, it will adjust the power in steps at a preset frequency, such as once every 20 seconds, and with an adjustment increment of 1% of the total power. That is, the power output will increase from the current level, say 50%, to 51% after 20 seconds, and if the rate still doesn't meet the target after another 20 seconds, it will continue to increase to 52%, and so on, until the heating rate returns to the reference range. Conversely, if the heating is too rapid, the power will be gradually reduced. This gentle, low-frequency adjustment effectively suppresses power peaks, making the energy consumption curve of the entire heating process smoother, thus achieving energy savings.

[0047] Specifically, within the second temperature range where temperature stability is prioritized, the steps for implementing the second power control strategy to output heating power include: Calculate the temperature deviation between the current temperature and the preset target temperature in real time; When the temperature deviation exceeds the second temperature fluctuation tolerance, the power compensation amount is calculated based on the temperature deviation and the preset proportional coefficient. The heating power is adjusted in real time according to the power compensation amount so that the temperature deviation value returns to the second temperature fluctuation tolerance.

[0048] In one embodiment, once the furnace temperature enters the second temperature range, the goal is to stabilize it at 1050 degrees Celsius. The preset second temperature fluctuation tolerance is ±1.5 degrees Celsius. The control system internally stores one or more preset proportional coefficients, which characterize how much power change is required to respond to a unit temperature change. For example, in a simple proportional control, the preset proportional coefficient is 20 kilowatts per degree Celsius.

[0049] During the heat preservation process, assuming that due to heat dissipation from the furnace body, the average temperature inside the furnace slowly decreases from 1050.5 degrees Celsius to 1048.3 degrees Celsius. At this point, the temperature deviation calculated by the control system is 1048.3 minus 1050, which is -1.7 degrees Celsius. The absolute value of this deviation, 1.7 degrees Celsius, exceeds the tolerance of 1.5 degrees Celsius.

[0050] The control system immediately triggers power compensation calculation. Based on the deviation value and the proportional gain, the calculated power compensation is -1.7 degrees Celsius multiplied by a negative proportional gain to form negative feedback, or simply the power that needs to be increased. If the compensation is defined to have the opposite sign to the deviation value, the power compensation is a positively correlated value.

[0051] Upon receiving this command, the power regulation module immediately adds a compensation amount to the current baseline insulation power and outputs it to the heater. This increase in heating power quickly suppresses the temperature drop and raises it back to the target temperature of around 1050 degrees Celsius. When the temperature returns to within the tolerance range, such as 1049.5 degrees Celsius, the deviation decreases, and the power compensation amount decreases or is reset to zero, thus achieving dynamic and stable temperature control. This highly sensitive response mechanism is the core of ensuring temperature stability during critical process stages.

[0052] Furthermore, the steps for calculating the power compensation amount based on the temperature deviation value and the preset proportional coefficient include: Obtain the preset scaling factor; Real-time acquisition of environmental media parameters inside the brazing furnace, including at least one of pressure information and flow information; Assess whether the heat transfer efficiency in the brazing furnace has deviated based on environmental medium parameters; If the heat transfer efficiency deviates, the preset proportional coefficient is corrected according to the change range of the environmental medium parameters to obtain the corrected proportional coefficient, and the corrected proportional coefficient is used as the effective proportional coefficient; otherwise, the preset proportional coefficient is used as the effective proportional coefficient. The power compensation is calculated based on the temperature deviation value and the effective proportionality coefficient.

[0053] The assessment of whether the heat transfer efficiency within the brazing furnace deviates based on environmental medium parameters involves analyzing real-time pressure and flow information to determine if the heat transfer efficiency differs from the initial set value. Specifically, this can be achieved by comparing real-time environmental medium parameters with a preset reference range; if the environmental medium parameters exceed the preset reference range, the heat transfer efficiency is considered to have deviated.

[0054] In one embodiment, the brazing furnace uses nitrogen as a protective atmosphere, and its flow rate is controlled by a mass flow controller. The standard process flow is set to a nitrogen flow rate of 20 cubic meters per hour, and the previously mentioned proportionality coefficient, such as 20 kilowatts per degree Celsius, is also tuned to this standard flow rate. In addition to monitoring the temperature, the control system also monitors the actual flow rate value fed back from the mass flow controller in real time.

[0055] Assume that during the heat preservation process in the second temperature range, pressure fluctuations in the external gas supply network cause the actual nitrogen flow rate entering the furnace to rise to 25 cubic meters per hour. This increased flow rate means enhanced convective heat transfer within the furnace, which would allow the heating elements to transfer heat to the workpiece more quickly. However, it could also lead to more heat being carried away by the flowing gas, altering the original thermal equilibrium. The system detects that the flow rate deviates from the preset reference range, a significant deviation in heat transfer efficiency.

[0056] At this point, the control system invokes a correction model to adjust the proportional gain. This model can be a simple lookup table or a function. For example, the correction function could be set such that the corrected proportional gain equals the preset proportional gain multiplied by a correction factor, where the correction factor is related to the rate of change of flow (i.e., the magnitude of change). For instance, when the flow rate increases, the system response may need to become more moderate to prevent overshoot, thus requiring a reduction in the proportional gain. The corrected proportional gain might become 18 kW per degree Celsius. This 18 kW per degree Celsius becomes the effective proportional gain for the current calculation. Subsequently, when temperature deviations occur again, the system will use this corrected factor to calculate the power compensation, making the power adjustment more suitable for the current actual heat transfer conditions.

[0057] In another parallel embodiment, for a vacuum brazing furnace, the environmental medium parameter is the vacuum level (pressure information) within the furnace. Changes in vacuum level significantly affect the heat transfer efficiency of thermal radiation and residual gas convection. The control system acquires the pressure readings of the vacuum gauge in real time. When the vacuum level changes (e.g., a slight leak causing a pressure increase), the system also assesses the deviation in heat transfer efficiency and dynamically corrects the proportional gain. For example, a pressure increase means more gas molecules and enhanced convective heat transfer; the system may accordingly lower the proportional gain to adapt to this change. In this way, the control system is no longer a rigid executor but an intelligent agent capable of proactively sensing changes in operating conditions and adjusting its behavior, thereby maintaining excellent temperature control performance under various disturbances.

[0058] Specifically, in order to achieve a smooth tightening of control constraints, the steps to reduce the current temperature fluctuation tolerance include: Determine the end temperature of the first temperature range and the start temperature of the second temperature range. The tolerance shrinkage factor is calculated based on the linear ratio between the current temperature at the end of the first temperature range and the starting temperature of the second temperature range. The difference between the first temperature fluctuation tolerance and the second temperature fluctuation tolerance is weighted using a tolerance shrinkage coefficient so that the current temperature fluctuation tolerance decreases linearly from the first temperature fluctuation tolerance to the second temperature fluctuation tolerance.

[0059] In one embodiment, the transition temperature range is 900°C to 1030°C. A first temperature fluctuation tolerance is ±10°C, and a second temperature fluctuation tolerance is ±1.5°C. Once the average furnace temperature enters this range, the control system begins to perform tolerance reduction calculations.

[0060] First, the system determines the boundaries of the interval: T_start = 900°C, T_end = 1030°C. It also determines the tolerance boundaries: Tol_1 = 10°C, Tol_2 = 1.5°C.

[0061] For any current temperature T_current within this range, the system calculates a linear scaling factor, i.e., the tolerance shrinkage coefficient k: k=(T_current-T_start) / (T_end-T_start) The value of this coefficient k increases linearly from 0 to 1 as T_current rises from 900°C to 1030°C.

[0062] Then, the system uses this coefficient k to calculate the current instantaneous temperature fluctuation tolerance Tol_current = Tol_1 - k * (Tol_1 - Tol_2) For example, when the furnace temperature rises to 965°C, it is exactly the midpoint of the transition range. At this time, k = (965-900) / (1030-900) = 65 / 130 = 0.5.

[0063] Therefore, the temperature fluctuation tolerance at this moment is 10 - 0.5 * (10 - 1.5) = 10 - 4.25 = 5.75°C.

[0064] This means that at the temperature of 965°C, the system allows a temperature fluctuation range of ±5.75°C. This tolerance is stricter than ±10°C in the first range but more lenient than ±1.5°C in the second range, placing it in a transitional state. As the temperature continues to rise, the k value increases, and Tol_current will continue to decrease smoothly until it reaches ±1.5°C at 1030°C, seamlessly connecting with the second temperature range.

[0065] Furthermore, steps to increase the weight of temperature stability in current power control strategies may include: Obtain the first power output value of the first power control strategy and the second power output value generated by the second power control strategy; The final heating power is obtained by calculating the weighted average of the first power output value and the second power output value. As the current temperature rises within the transition temperature range, the weight of the first power output value is gradually reduced, while the weight of the second power output value is gradually increased.

[0066] In one embodiment, within the transition temperature range, the control system runs two independent calculation logics in parallel: one calculates the recommended power output value P1 according to a first power control strategy; the other calculates the recommended power output value P2 according to a second power control strategy.

[0067] The final heating power P_final sent to the power regulator is obtained through weighted averaging. The weights can also be allocated using the aforementioned linear proportional coefficient k. The weight W1 of the first power control strategy can be set to (1-k), and the weight W2 of the second power control strategy can be set to k.

[0068] P_final=P1*W1+P2*W2=P1*(1-k)+P2*k Continuing with the example of a furnace temperature reaching 965°C (k=0.5), let's assume that at this point, the first power control strategy, based on the current heating rate, determines that only 45kW of power is needed to maintain economical heating, i.e., P1=45kW. The second power control strategy, however, calculates that based on the slight deviation between the current temperature and the ideal curve, 60kW of power is needed to quickly eliminate the deviation, i.e., P2=60kW. Therefore, the final output power is: P_final=45*(1-0.5)+60*0.5=22.5+30=52.5kW.

[0069] This 52.5kW output power represents a smooth compromise, balancing energy efficiency (lower than 60kW) with stability requirements (higher than 45kW). When the temperature just reaches 900°C, k approaches 0, and P_final will be very close to P1; when the temperature is about to leave 1030°C, k approaches 1, and P_final will be very close to P2. In this way, the control mechanism smoothly transitions from energy efficiency to stability.

[0070] In a preferred embodiment, after calculating the weighted average of the first power output value and the second power output value to obtain the final heating power, the method further includes: Real-time monitoring of the instantaneous output deviation between the first power output value and the second power output value; If the instantaneous output deviation exceeds the preset strategy conflict threshold, the maximum allowable range of a single heating power adjustment is dynamically adjusted according to the magnitude of the instantaneous output deviation, and the heating power is smoothly switched from the current heating power to the final heating power based on the maximum allowable range of a single heating power adjustment; otherwise, the heating power is smoothly switched from the current heating power to the final heating power based on the preset adjustment range.

[0071] Specifically, the system presets a policy conflict threshold of 30kW and a maximum allowable range of 5kW for a single power adjustment.

[0072] During operation, the system calculates the instantaneous output deviation value Delta_P=|P1-P2| in real time.

[0073] If Delta_P is less than or equal to 30kW, the discrepancy between the two strategies is within an acceptable range. The system will adjust step by step from the current power to the calculated P_final, following the conventional maximum adjustment increment of 5kW.

[0074] If Delta_P is greater than 30kW, for example, reaching 50kW, it indicates a severe policy conflict. In this case, the system will dynamically reduce the maximum allowable range for a single adjustment. For example, the new maximum allowable range can be set to: 5kW * (30kW / 50kW) = 3kW. This means that the system will approach the target power P_final with smaller steps and at a slower pace. This slow braking approach, while extending the time to reach the target power, effectively avoids drastic power jumps caused by policy conflicts, further ensuring the smoothness of the transition process.

[0075] Furthermore, during the execution of the smooth switching logic, the method may also include: The temperature difference between multiple temperature measuring points distributed in the brazing furnace is compared in real time. If the maximum temperature difference among the multiple temperature measuring points is greater than or equal to the preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is suspended, and differentiated heating power compensation is performed on the area corresponding to the multiple temperature measuring points to reduce the maximum temperature difference. When the maximum temperature difference decreases to less than the preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is resumed.

[0076] In one embodiment, the system presets a temperature field balance threshold of 20°C. Throughout the entire transition temperature range, in addition to performing the aforementioned tolerance contraction and strategy weight switching, the system also performs parallel temperature field uniformity monitoring, acquires the temperatures of all temperature measurement points, such as the aforementioned five thermocouples, in real time, and calculates the highest temperature T_max and the lowest temperature T_min, obtaining the maximum temperature difference value Max_Diff = T_max - T_min.

[0077] Assuming that when the furnace temperature rises to 980°C, the uneven placement of the workpieces causes the temperature at the center of the furnace (T_max=995°C) to be significantly higher than the temperature near the furnace door (T_min=970°C), with the maximum temperature difference reaching 25°C, exceeding the equilibrium threshold of 20°C.

[0078] At this point, the system will immediately trigger the temperature field equalization priority mode, and the coefficient k of the weights W1 and W2 will be frozen at the current value and will no longer change with the increase of temperature. This means that the center of gravity of the control strategy will temporarily no longer tilt towards the stable direction. If the brazing furnace is equipped with a zone heating function, for example, the furnace body is divided into three independent heating zones: upper, middle, and lower, the system will identify that the area where T_min is located is close to the furnace door and may belong to the lower heating zone, and increase the heating power of that area separately; at the same time, it will identify that the area where T_max is located is the center of the furnace and may belong to the middle heating zone, and appropriately reduce the heating power of that area.

[0079] This differentiated heating process continues until the system detects that the maximum temperature difference, Max_Diff, has fallen back below 20°C. Once the temperature field becomes uniform, the system will lift the pause and resume the normal switching process of the strategy weights, allowing the control center to continue transitioning smoothly towards stability. This mechanism ensures that the brazing furnace enters the second temperature range, which has the most stringent requirements for temperature stability, in a uniform thermal state, laying a solid foundation for high-quality brazing.

[0080] Secondly, see Figure 2 This application also provides an energy-saving brazing furnace heating process temperature adaptive control system for executing the energy-saving brazing furnace heating process temperature adaptive control method described in any of the preceding claims. The system includes: The interval division module 210 is used to divide the heating process of the brazing furnace into at least three continuous temperature intervals, including a first temperature interval, a second temperature interval located after the first temperature interval, and a transition temperature interval from the first temperature interval to the second temperature interval. The strategy configuration module 220 is used to configure a first power control strategy and a first temperature fluctuation tolerance for a first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and to configure a second power control strategy and a second temperature fluctuation tolerance for a second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is less than the first temperature fluctuation tolerance. The interval judgment module 230 is used to obtain the current temperature of the brazing furnace in real time and determine the current temperature interval of the brazing furnace based on the current temperature. The strategy execution module 240 is used to execute a first power control strategy to output heating power when it is determined that the brazing furnace is currently in a first temperature range, so that the characteristic temperature fluctuation is within the first temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in a second temperature range, it executes a second power control strategy to output heating power, so that the characteristic temperature fluctuation is within the second temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in a transition temperature range, it executes smooth switching logic, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

[0081] The system also includes an amplitude adjustment module, which is used to monitor the instantaneous output deviation between the first power output value and the second power output value in real time after the step of calculating the weighted average of the first power output value and the second power output value to obtain the final heating power; If the instantaneous output deviation exceeds the preset strategy conflict threshold, the maximum allowable range of a single heating power adjustment is dynamically adjusted according to the magnitude of the instantaneous output deviation, and the heating power is smoothly switched from the current heating power to the final heating power based on the maximum allowable range of a single heating power adjustment; otherwise, the heating power is smoothly switched from the current heating power to the final heating power based on the preset adjustment range.

[0082] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for adaptive control of the temperature in the heating process of an energy-saving brazing furnace, characterized in that, The method includes: The heating process of the brazing furnace is divided into at least three consecutive temperature ranges, including a first temperature range, a second temperature range following the first temperature range, and a transition temperature range from the first temperature range to the second temperature range. A first power control strategy and a first temperature fluctuation tolerance are configured for the first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and a second power control strategy and a second temperature fluctuation tolerance are configured for the second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is less than the first temperature fluctuation tolerance. The current temperature of the brazing furnace is acquired in real time, and the current temperature range of the brazing furnace is determined based on the current temperature. When it is determined that the brazing furnace is currently in the first temperature range, the first power control strategy is executed to output heating power so that the characteristic temperature is within the first temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in the second temperature range, the second power control strategy is executed to output heating power so that the characteristic temperature is within the second temperature fluctuation tolerance; when it is determined that the brazing furnace is currently in the transition temperature range, a smooth switching logic is executed, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

2. The energy-saving process temperature adaptive control method for a brazing furnace according to claim 1, characterized in that, The step of acquiring the current temperature of the brazing furnace in real time and determining the current temperature range of the brazing furnace based on the current temperature includes: Acquire real-time temperature data from multiple temperature measuring points distributed within the brazing furnace; The real-time temperature data from the multiple temperature measurement points are averaged to obtain the average temperature value, which is used as the current temperature. The average temperature value is compared with a preset interval switching threshold to determine the current temperature interval of the brazing furnace.

3. The energy-saving process temperature adaptive control method for a brazing furnace according to claim 1, characterized in that, The step of executing the first power control strategy to output heating power includes: Obtain the real-time characteristic temperature rise rate of the brazing furnace; If the real-time characteristic temperature rise rate is within the preset reference rate range, then the current heating power output is maintained. If the real-time characteristic temperature rise rate is not within the preset reference rate range, the heating power is finely adjusted in steps according to the degree of deviation of the real-time characteristic temperature rise rate, with a preset adjustment frequency and adjustment range.

4. The energy-saving process temperature adaptive control method for a brazing furnace according to claim 1, characterized in that, The step of executing the second power control strategy to output heating power includes: Calculate the temperature deviation between the current temperature and the preset target temperature in real time; When the temperature deviation exceeds the second temperature fluctuation tolerance, the power compensation amount is calculated based on the temperature deviation and a preset proportional coefficient. The heating power is adjusted in real time according to the power compensation amount so that the temperature deviation value returns to within the second temperature fluctuation tolerance.

5. The energy-saving process temperature adaptive control method for a brazing furnace according to claim 4, characterized in that, The step of calculating the power compensation amount based on the temperature deviation value and the preset proportional coefficient includes: Obtain the preset scaling factor; Real-time acquisition of environmental media parameters within the brazing furnace, wherein the environmental media parameters include at least one of pressure information and flow information; Evaluate whether the heat transfer efficiency in the brazing furnace has deviated based on the environmental medium parameters; If the heat transfer efficiency deviates, the preset proportional coefficient is corrected according to the change range of the environmental medium parameters to obtain the corrected proportional coefficient, and the corrected proportional coefficient is used as the effective proportional coefficient; otherwise, the preset proportional coefficient is used as the effective proportional coefficient. The power compensation amount is calculated based on the temperature deviation value and the effective proportionality coefficient.

6. The method of claim 1, wherein the method is characterized by: The step of reducing the current temperature fluctuation tolerance includes: Determine the end temperature of the first temperature range and the start temperature of the second temperature range; The tolerance shrinkage factor is calculated based on the linear ratio between the current temperature at the end of the first temperature range and the starting temperature of the second temperature range. The difference between the first temperature fluctuation tolerance and the second temperature fluctuation tolerance is weighted using the tolerance shrinkage coefficient so that the current temperature fluctuation tolerance decreases linearly from the first temperature fluctuation tolerance to the second temperature fluctuation tolerance.

7. The method for adaptive temperature control in the heating process of an energy-saving brazing furnace according to claim 1, characterized in that, The steps to increase the weight of temperature stability in the current power control strategy include: Obtain the first power output value of the first power control strategy and the second power output value generated by the second power control strategy; The final heating power is obtained by calculating the weighted average of the first power output value and the second power output value, wherein as the current temperature rises within the transition temperature range, the weight of the first power output value is gradually reduced, and the weight of the second power output value is gradually increased.

8. The energy-saving brazing furnace heating process temperature adaptive control method according to claim 7, characterized in that, After the step of calculating the weighted average of the first power output value and the second power output value to obtain the final heating power, the following is included: Real-time monitoring of the instantaneous output deviation between the first power output value and the second power output value; If the instantaneous output deviation exceeds the preset strategy conflict threshold, the maximum allowable range of a single heating power adjustment is dynamically adjusted according to the magnitude of the instantaneous output deviation, and the heating power is smoothly switched from the current heating power to the final heating power based on the maximum allowable range of the single heating power adjustment; otherwise, the heating power is smoothly switched from the current heating power to the final heating power based on the preset adjustment range.

9. The method for adaptive temperature control in the heating process of an energy-saving brazing furnace according to claim 1, characterized in that, During the execution of the smooth switching logic, the method further includes: The temperature difference between multiple temperature measuring points distributed in the brazing furnace is compared in real time. If the maximum temperature difference among the multiple temperature measuring points is greater than or equal to a preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is suspended, and differentiated heating power compensation is performed on the area corresponding to the multiple temperature measuring points to reduce the maximum temperature difference. When the maximum temperature difference decreases to less than the preset balance threshold, the step of increasing the weight of temperature stability in the current power control strategy is resumed.

10. An energy-saving brazing furnace heating process temperature adaptive control system, used to execute the energy-saving brazing furnace heating process temperature adaptive control method as described in any one of claims 1 to 9, characterized in that, The system includes: The interval division module is used to divide the heating process of the brazing furnace into at least three consecutive temperature intervals, including a first temperature interval, a second temperature interval located after the first temperature interval, and a transition temperature interval from the first temperature interval to the second temperature interval. The strategy configuration module is used to configure a first power control strategy and a first temperature fluctuation tolerance for the first temperature range, wherein the first power control strategy prioritizes limiting energy consumption; and to configure a second power control strategy and a second temperature fluctuation tolerance for the second temperature range, wherein the second power control strategy prioritizes temperature stability, and the second temperature fluctuation tolerance is less than the first temperature fluctuation tolerance. The interval determination module is used to obtain the current temperature of the brazing furnace in real time and determine the current temperature interval of the brazing furnace based on the current temperature. The strategy execution module is configured to, when determining that the brazing furnace is currently in the first temperature range, execute the first power control strategy to output heating power, so that the characteristic temperature fluctuation is within the first temperature fluctuation tolerance; when determining that the brazing furnace is currently in the second temperature range, execute the second power control strategy to output heating power, so that the characteristic temperature fluctuation is within the second temperature fluctuation tolerance; and when determining that the brazing furnace is currently in the transition temperature range, execute smooth switching logic, wherein the smooth switching logic includes shrinking the current temperature fluctuation tolerance and increasing the weight of temperature stability in the current power control strategy.

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