Vapor concentration stable control method and device, electronic equipment, medium and product

Abstract

This invention relates to the field of semiconductor formic acid reflow soldering technology, and discloses a vapor concentration stabilization control method, device, electronic device, medium, and product. The method includes: calculating a feedforward compensation amount to compensate for temperature changes caused by evaporation endothermic of the liquid raw material based on the current temperature and current remaining mass of the liquid raw material, and the molar flow rate of the carrier gas, according to a pre-established thermal balance model; calculating a feedback correction amount based on the concentration deviation between the current concentration of the raw material vapor in the mixed vapor and the target concentration; superimposing the feedforward compensation amount and the feedback correction amount to obtain a control output amount, which is then transmitted to the thermal management actuator of the liquid raw material. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed to control the concentration of liquid raw material vapor in the mixed vapor. This invention solves the problem that feedback control cannot timely suppress the drop in liquid temperature and concentration drift due to heating lag.

Description

Technical Field

[0001] This invention relates to the field of semiconductor process control technology, specifically to methods, devices, electronic equipment, media, and products for stable control of vapor concentration. Background Technology

[0002] Formic acid reflow soldering utilizes the reducing properties of formic acid (HCOOH) vapor at high temperatures to remove solder oxides, achieving high-quality soldering without flux or cleaning. This process requires a continuous flow of a stable concentration (approximately 5% by volume) of formic acid / nitrogen mixture into the reflow oven chamber.

[0003] Existing formic acid vapor generation systems generally employ a bubbling method combined with closed-loop PID (Proportional-Integral-Derivative) control. Nitrogen gas carries saturated formic acid vapor from the bubbling tank into the reflow oven chamber. A non-dispersive infrared (NDIR) sensor detects the concentration, and the flow rate of the mass flow controller (MFC) or the heating jacket power is adjusted to achieve concentration stability. However, the endothermic evaporation of formic acid causes a continuous decrease in liquid temperature, leading to an exponential decrease in saturated vapor pressure. Even with constant flow rate and heating power, the outlet concentration exhibits a slow drift over several tens of minutes. Conventional PID control is limited by the heating hysteresis caused by the large heat capacity of the liquid, failing to suppress this drift in time. Forcibly increasing the heating power easily causes overshoot and temperature oscillations. While increasing the nitrogen flow rate can temporarily increase the vapor carrying capacity, it accelerates evaporation and cooling, exacerbating concentration deterioration. Ultimately, this results in an unacceptably slow drift in formic acid concentration during the reflow soldering process, severely impacting soldering repeatability and weld consistency. Summary of the Invention

[0004] This invention provides a method, device, electronic equipment, medium, and product for stable vapor concentration control, in order to solve the problems in the prior art where evaporation cooling leads to a continuous drop in liquid temperature and slow concentration drift, while feedback control is limited by heating lag and cannot make advance predictions or timely and effective compensation.

[0005] In a first aspect, the present invention provides a method for stabilizing and controlling vapor concentration, used to control the concentration of raw material vapor in a mixed vapor formed by the evaporation of liquid raw materials carried by a carrier gas, the method comprising: Obtain the current temperature and current remaining mass of the liquid feedstock, as well as the molar flow rate of the carrier gas; Based on the current temperature and remaining mass of the liquid feedstock, and the molar flow rate of the carrier gas, a feedforward compensation amount is calculated according to a pre-established heat balance model to compensate for the temperature change caused by the evaporation heat absorption of the liquid feedstock. The heat balance model is based on the heat conservation relationship of the liquid feedstock, which consists of the balance between the change in the internal energy of the liquid feedstock, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount. The specific heat capacity, latent heat of vaporization of the liquid feedstock, the heat transfer coefficient of the environment, the carrier gas flow rate, the saturated vapor pressure, and the total outlet pressure are used as characteristic parameters. Obtain the current concentration of the raw material vapor in the mixed steam, and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration; The control output is obtained by superimposing the feedforward compensation and the feedback correction. The control output is transmitted to the thermal management actuator of the liquid feedstock. The thermal management actuator adjusts the temperature of the liquid feedstock, and the saturated vapor pressure of the liquid feedstock is changed by adjusting the temperature of the liquid feedstock, so as to control the concentration of liquid feedstock vapor in the mixed vapor.

[0006] This invention provides a method for stable vapor concentration control. By establishing a heat balance model that includes evaporation heat absorption, ambient heat exchange, and liquid heat capacity, and by calculating the feedforward compensation amount in real time based on the heat balance model, the method actively outputs compensation heat before the liquid temperature drops due to evaporation cooling. This solves the problem in existing technologies where feedback control cannot timely suppress liquid temperature drop and concentration drift due to heating lag. The feedforward compensation amount is calculated and output before the temperature drops, which also solves the fundamental defect of feedback control that cannot predict in advance due to reliance on deviation signals. At the same time, by superimposing the feedforward compensation amount and the feedback correction amount and transmitting them to the thermal management actuator, the feedback correction amount only needs to correct the small residual after feedforward compensation, avoiding overshoot, oscillation, and concentration deterioration caused by simply increasing the heating power or carrier gas flow rate. The thermal management actuator adjusts the temperature of the liquid feedstock, thereby changing the saturated vapor pressure of the liquid feedstock and controlling the concentration of liquid feedstock vapor in the mixed vapor, thus achieving constant liquid temperature and long-term stability of outlet vapor concentration.

[0007] In one optional implementation, a feedforward compensation amount is calculated based on a pre-established heat balance model to compensate for temperature changes caused by the evaporation and heat absorption of the liquid raw material, including: To obtain the latent heat of vaporization and molar mass of liquid feedstock; Determine the saturated vapor pressure of the liquid feedstock at the current temperature, based on the current temperature, latent heat of vaporization, and molar mass. The mole fraction of the feed vapor in the mixed vapor is determined based on the saturated vapor pressure and the total pressure at the outlet of the mixed vapor. Calculate the current evaporation mass flow rate of the liquid feedstock based on the molar flow rate and molar fraction of the carrier gas; Calculate the heat carried away by evaporation based on the current evaporation mass flow rate and latent heat of vaporization; Calculate the heat transferred to the environment based on the difference between the current temperature and the ambient temperature and the preset heat transfer coefficient; When the temperature change rate of the liquid feedstock is zero, the feedforward compensation is calculated based on the heat carried away by evaporation and the heat transferred in from the environment.

[0008] In the above technical solution, based on real-time state quantities such as the current temperature of the liquid raw material, the molar flow rate of the carrier gas, and the ambient temperature difference, the saturated vapor pressure, mole fraction, evaporation mass flow rate, heat carried away by evaporation, and heat transferred to the environment are calculated sequentially. Then, combined with the current remaining mass and specific heat capacity, the feedforward compensation amount is calculated. Thus, the compensation amount to offset the effect can be predicted and output before the temperature drop caused by evaporation cooling, thereby realizing the proactive suppression of the temperature change of the liquid raw material in advance.

[0009] In one optional implementation, the formula for calculating the feedforward compensation amount is as follows: ; in, This is the feedforward compensation amount, representing the feedforward power calculated in real time. To remove heat through evaporation, Heat is transferred to the environment. The current temperature of the liquid raw material. The molar flow rate of the carrier gas. Indicates the type of carrier gas. It is the saturated vapor pressure. This is the total pressure at the outlet of the mixed vapor. The latent heat of vaporization of liquid feedstock, The heat transfer coefficient is... For ambient temperature, At the current sampling time, This represents the temperature difference as a function of the sampling time.

[0010] In one alternative implementation, the method further includes: When the change in the current remaining mass exceeds a preset mass threshold, and / or when the change in the ambient temperature exceeds a preset temperature threshold, at least one parameter in the thermal balance model is updated.

[0011] In one alternative implementation, updating at least one parameter in the thermal equilibrium model includes: Re-identify the heat transfer coefficients in the thermal equilibrium model; Update the specific heat capacity and current remaining mass of the liquid feedstock.

[0012] In the above technical solution, by updating the parameters in the thermal balance model in a timely manner when the change in the remaining mass of liquid raw materials and / or the change in ambient temperature exceeds a preset threshold, the calculation of the feedforward compensation amount can always match the actual working conditions after the change, thus avoiding compensation deviation caused by model mismatch due to liquid level drop or ambient temperature change.

[0013] In one optional implementation, the feedback correction amount is calculated based on the concentration deviation between the current concentration and the target concentration, including: Calculate the concentration deviation between the current concentration and the target concentration; Based on the concentration deviation, a closed-loop control algorithm is used to calculate the feedback correction amount.

[0014] In the above technical solution, the deviation between the current concentration and the target concentration is calculated, and the feedback correction amount is calculated in real time using a closed-loop control algorithm. The residual deviation after feedforward compensation is continuously corrected, thereby eliminating the influence of model error and environmental disturbance on the concentration control accuracy and ensuring that the outlet steam concentration is stable near the target value.

[0015] In one optional implementation, the closed-loop control algorithm is an incremental PID algorithm. Based on the concentration deviation, a closed-loop control algorithm is used to calculate the feedback correction amount, including: Obtain the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation between the two previous sampling times; Based on the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation between the two previous sampling times, the increment of the feedback correction is calculated using the incremental PID algorithm. The feedback correction amount at the current sampling moment is determined based on the increment of the feedback correction amount.

[0016] In the above technical solution, by adopting an incremental PID algorithm, the increment of the feedback correction amount is calculated based on the concentration deviation at the current, previous, and two previous sampling times. Then, the feedback correction amount at the current time is determined by the increment. This ensures that each output is only the change in the correction amount rather than the absolute value, thereby avoiding sudden output changes caused by integral saturation. It is particularly suitable for scenarios where only small residual correction is needed after feedforward compensation.

[0017] In one optional implementation, when the absolute value of the concentration deviation is less than a preset threshold, the feedback correction amount is zero or remains unchanged.

[0018] In the above technical solution, by making the feedback correction amount zero or unchanged when the absolute value of the concentration deviation is less than the preset threshold, the reciprocating adjustment of the thermal management actuator and concentration oscillation caused by frequent actions of the feedback control when the feedforward compensation has brought the concentration close to the target value are avoided, thus ensuring the output stability of the system under steady-state conditions.

[0019] In one optional implementation, the formula for calculating the feedback correction amount is as follows: ; in, For feedback correction amount, , and These represent the proportional coefficient, integral coefficient, and derivative coefficient of the incremental PID algorithm, respectively. This represents the concentration deviation at the current sampling time. This represents the concentration deviation at the previous sampling time, which is the first sampling time before the current time. This represents the concentration difference between the previous two sampling times, where the previous two sampling times are the second sampling time before the current time. The sampling period.

[0020] In one optional implementation, the control output is transmitted to a thermal management actuator for the liquid feedstock, and the thermal management actuator is used to regulate the temperature of the liquid feedstock, including: Generate drive signals based on control output; The drive signal is transmitted to the thermal management actuator, which responds to the drive signal and adjusts the temperature of the liquid raw material.

[0021] In the above technical solution, by generating a drive signal based on the control output and transmitting it to the thermal management actuator, the thermal management actuator directly adjusts the temperature of the liquid raw material in response to the drive signal. This realizes the conversion of the control output from a calculated value to a physical execution, ensuring that the actual effects of feedforward compensation and feedback correction can be accurately applied to the liquid raw material.

[0022] Secondly, the present invention provides a vapor concentration stabilization control system for controlling the concentration of raw material vapor in a mixed vapor formed by the evaporation of liquid raw materials carried by a carrier gas. The system includes: A bubbling tank is used to contain liquid raw materials and is equipped with a carrier gas inlet pipe and a mixed vapor outlet pipe. A liquid temperature sensor, immersed in liquid raw materials, is used to detect the temperature of the liquid raw materials; An ambient temperature sensor, located on the outside of the bubbling tank, is used to detect the ambient temperature. A level / mass sensor is installed on the tank body of the bubbling tank to detect the remaining mass of the liquid raw material; A heating / cooling jacket, surrounding the bubbling tank, is used to regulate the temperature of the liquid feedstock; A concentration sensor, installed at the outlet pipe of the mixed steam, is used to detect the concentration of the raw material steam in the mixed steam. A pressure sensor is installed at the outlet pipe of the mixed steam to detect the total pressure at the outlet pipe of the mixed steam. The controller is communicatively connected to a liquid temperature sensor, an ambient temperature sensor, a liquid level / mass sensor, a concentration sensor, a pressure sensor, and a heating / cooling jacket. The controller is used to execute the vapor concentration stabilization control method of the first aspect or any corresponding embodiment described above.

[0023] Thirdly, the present invention provides a vapor concentration stabilization control device for controlling the concentration of raw material vapor in a mixed vapor formed by the evaporation of liquid raw materials carried by a carrier gas. The device includes: The data acquisition module is used to acquire the current temperature and current remaining mass of the liquid raw material, as well as the molar flow rate of the carrier gas; The feedforward calculation module is used to calculate the feedforward compensation amount to compensate for the temperature change of the liquid feedstock due to the heat absorption of evaporation, based on the current temperature and current remaining mass of the liquid feedstock and the molar flow rate of the carrier gas, according to a pre-established heat balance model. The heat balance model is established based on the heat conservation relationship of the liquid feedstock, which consists of the balance between the change of internal energy of the liquid feedstock, the heat removed by evaporation, the heat transferred from the environment, and the external heating amount, and uses the specific heat capacity, latent heat of vaporization of the liquid feedstock, the heat transfer coefficient of the environment, the carrier gas flow rate, the saturated vapor pressure, and the total outlet pressure as characteristic parameters. The feedback calculation module is used to obtain the current concentration of the raw material vapor in the mixed vapor and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration. The superposition module is used to superimpose the feedforward compensation amount and the feedback correction amount to obtain the control output amount; The transmission module is used to transmit the control output to the thermal management actuator of the liquid raw material to regulate the temperature of the liquid raw material.

[0024] Fourthly, the present invention provides an electronic device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to perform the vapor concentration stabilization control method of the first aspect or any corresponding embodiment described above.

[0025] Fifthly, the present invention provides a computer-readable storage medium storing computer instructions for causing a computer to execute the vapor concentration stabilization control method of the first aspect or any corresponding embodiment thereof.

[0026] In a sixth aspect, the present invention provides a computer program product, including computer instructions for causing a computer to execute the vapor concentration stabilization control method of the first aspect or any corresponding embodiment described above.

[0027] This invention addresses the problem in existing technologies where evaporation cooling leads to a continuous decrease in liquid temperature and slow concentration drift, while feedback control is limited by heating lag and cannot compensate effectively in a timely manner. It provides a method for stable vapor concentration control. By acquiring the current temperature, current remaining mass, and current carrier gas flow rate of the liquid feedstock, a feedforward compensation amount is calculated based on a pre-established heat balance model to compensate for temperature changes caused by evaporation heat absorption. The current concentration of feedstock vapor in the mixed vapor is also acquired to calculate a feedback correction amount. The feedforward compensation amount and the feedback correction amount are then superimposed and transmitted to the thermal management actuator to adjust the liquid feedstock temperature. By adjusting the liquid feedstock temperature, the saturated vapor pressure of the liquid feedstock is changed, thereby controlling the concentration of liquid feedstock vapor in the mixed vapor. This achieves stable control under liquid feedstock reflow soldering conditions. This system achieves a constant liquid temperature and a long-term high stability of the outlet concentration. By using a heat balance model to predict the heat absorption of evaporation in real time and outputting a feedforward compensation, it actively counteracts the evaporative cooling effect, fundamentally suppressing the downward trend of liquid temperature. The feedforward compensation is calculated and output before the temperature drops, thus solving the fundamental defect of feedback control that cannot predict in advance due to its reliance on deviation signals. At the same time, the feedback correction corrects the residual deviation after feedforward compensation, avoiding concentration drift caused by heating lag in pure feedback control, and overcoming overshoot, oscillation, and concentration deterioration caused by simply increasing heating power or carrier gas flow. Finally, it outputs a stable vapor concentration, improving welding repeatability and weld consistency in the reflow soldering process, and providing a reliable guarantee for closed-loop adjustment of process parameters. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a structural block diagram of the vapor concentration stabilization control system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the first process of the vapor concentration stabilization control method according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the second process of the vapor concentration stabilization control method according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the third process of the vapor concentration stabilization control method according to an embodiment of the present invention; Figure 5(a) is a comparison chart of the concentration control effects of embodiments of the present invention; Figure 5(b) is a comparison diagram of liquid temperature changes in an embodiment of the present invention; Figure 6 This is a structural block diagram of the vapor concentration stabilization control device according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0031] As an optional application scenario of this invention, such as Figure 1 The diagram shown is a block diagram of a vapor concentration stabilization control system. This system is used to control the concentration of feedstock vapor in the mixed vapor formed by the evaporation of liquid feedstock carried by the carrier gas. It includes: Bubble tank 101 is used to contain liquid raw materials and is equipped with a carrier gas inlet pipe and a mixed vapor outlet pipe; for example, the bubble tank contains liquid formic acid and is equipped with a nitrogen inlet pipe (with a mass flow controller) and a mixed gas outlet.

[0032] A liquid temperature sensor 102 is immersed in a liquid raw material to detect its temperature; for example, a high-precision Pt100 liquid temperature sensor is immersed in liquid formic acid to measure the current temperature of the liquid raw material. .

[0033] Ambient temperature sensor 103 is installed on the outside of the bubbling tank to detect ambient temperature. .

[0034] The level / mass sensor 104 is installed on the tank body of the bubbling tank to detect the current remaining mass of the liquid raw material. Alternatively, it can be calculated using the initial mass and the integral evaporation rate.

[0035] Heating / cooling jacket 105, surrounding the bubbling tank, is used to regulate the temperature of the liquid raw material and can be used at heating power. Active heating or cooling.

[0036] Concentration sensor 106 is installed at the outlet pipe of the mixed vapor and is used to detect the concentration of the raw material vapor in the mixed vapor, for example, to measure the volume concentration of formic acid in the mixed vapor. .

[0037] Pressure sensor 107 is installed at the mixed steam outlet pipe to detect the total pressure at the mixed steam outlet pipe, for example, to measure the total pressure at the bubbling tank outlet or furnace cavity. That is, the total pressure at the outlet of the mixed steam.

[0038] The controller 108 is communicatively connected to a liquid temperature sensor, an ambient temperature sensor, a liquid level / mass sensor, a concentration sensor, a pressure sensor, and a heating / cooling jacket. The controller receives signals from the aforementioned sensors to execute a vapor concentration stabilization control method, outputs a heating power command, and transmits it to the heating / cooling jacket. The heating / cooling jacket is used to adjust the temperature of the liquid raw material, thereby changing the saturated vapor pressure of the liquid raw material to control the concentration of liquid raw material vapor in the mixed vapor.

[0039] According to an embodiment of the present invention, a method for stabilizing and controlling vapor concentration is provided. It should be noted that, in the appendix... Figure 2 To be continued Figure 4 The steps shown in the flowchart can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0040] This embodiment provides a vapor concentration stabilization control method, which can be used in the aforementioned vapor concentration stabilization control system to control the concentration of raw material vapor in the mixed vapor formed by the evaporation of liquid raw materials carried by the carrier gas. Figure 2 This is a flowchart of a vapor concentration stabilization control method according to an embodiment of the present invention, such as... Figure 2 As shown, the process includes the following steps: Step S201: Obtain the current temperature and current remaining mass of the liquid raw material, as well as the molar flow rate of the carrier gas.

[0041] In this embodiment, formic acid is used as an example of a liquid raw material. The current temperature of the liquid raw material is... This refers to the real-time temperature value detected by a temperature sensor (such as Pt100) immersed in the liquid raw material.

[0042] Current remaining mass of liquid feedstock It refers to the real-time remaining mass of liquid raw material in the bubbling tank, which is detected by a level / mass sensor or calculated by the initial mass and the integral evaporation rate.

[0043] The molar flow rate of the carrier gas refers to the real-time molar flow rate or mass flow rate of the carrier gas (such as nitrogen) introduced into the liquid feedstock, which is detected and regulated by a mass flow controller (MFC) installed on the carrier gas inlet pipeline.

[0044] Step S202: Based on the current temperature and current remaining mass of the liquid feedstock, and the molar flow rate of the carrier gas, calculate the feedforward compensation amount to compensate for the temperature change caused by the evaporation heat absorption of the liquid feedstock according to the pre-established heat balance model. The heat balance model is established based on the heat conservation relationship of the liquid feedstock. The heat conservation relationship consists of the balance between the change of internal energy of the liquid feedstock, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount. The specific heat capacity, latent heat of vaporization of the liquid feedstock, the heat transfer coefficient of the environment, the carrier gas flow rate, the saturated vapor pressure, and the total outlet pressure are used as characteristic parameters.

[0045] When the liquid feedstock is formic acid, the differential equation of the pre-established heat balance model is as follows: (1); in: (2); Under the assumption of complete saturation, the molar fraction of formic acid in the outlet gas is: When carrier gas When nitrogen is used, the molar flow rate of nitrogen is The molar flow rate of formic acid evaporation is: (3); The formula for calculating the heat transfer from the environment to formic acid is: (4); in, To remove heat through evaporation, Heat is transferred to the environment. For heating power, For the current remaining mass, The specific heat capacity of the liquid raw material. The current temperature of the liquid raw material. This is the rate of temperature change of the liquid raw material. When the current temperature of the liquid raw material deviates from the set temperature, the rate of temperature change is determined based on the difference between the set temperature and the current temperature. The molar flow rate of nitrogen gas. It is the saturated vapor pressure. This is the total pressure at the outlet of the mixed vapor. The latent heat of vaporization of liquid feedstock, The heat transfer coefficient is determined through identification experiments. The ambient temperature.

[0046] Feedforward compensation It refers to the compensation power value calculated in real time based on the heat balance model, which is used to actively offset the temperature change trend caused by the evaporation and heat absorption of liquid raw materials.

[0047] Specifically, the current saturated vapor pressure of the liquid raw material is determined based on its current temperature, latent heat of vaporization, and molar mass. Then, the molar fraction of the raw material vapor in the mixed gas is calculated by combining the total pressure at the outlet pipe of the mixed vapor. This is multiplied by the molar flow rate of the carrier gas to obtain the current evaporation mass flow rate, thereby obtaining the heat carried away by evaporation. At the same time, the heat transferred to the environment is calculated based on the difference between the current temperature and the ambient temperature and the preset heat transfer coefficient. Finally, the feedforward compensation amount required to offset the heat absorption of evaporation is solved by combining the current remaining mass and specific heat capacity of the liquid raw material. This compensation amount can be updated in real time with changes in operating conditions and is actively output before the actual temperature drop.

[0048] Step S203: Obtain the current concentration of the raw material vapor in the mixed steam, and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration.

[0049] Here, mixed vapor refers to a gas mixture formed by mixing carrier gas and raw material vapor. For example, a mixture of nitrogen and formic acid vapor.

[0050] Raw material vapor refers to the gaseous product formed after the liquid raw material evaporates, such as formic acid vapor.

[0051] The feedback correction is a correction power value calculated in real time by the closed-loop control algorithm based on the concentration deviation between the current concentration and the target concentration. It is a corrective control quantity. After the feedforward compensation has offset most of the evaporation and cooling disturbances, it continuously corrects the residual concentration deviation to eliminate the influence of model errors, environmental disturbances and other factors on the concentration control accuracy.

[0052] Specifically, a concentration sensor installed at the outlet pipe of the mixed steam detects the current concentration of the raw material steam in the mixed steam in real time. The concentration deviation is obtained by subtracting the current concentration from the target concentration. This deviation is then calculated in real time using a closed-loop control algorithm to generate a feedback correction. If an incremental PID algorithm is used, the deviation values ​​at the current and two previous sampling times are further obtained. The increment of the correction is calculated based on these three values, and this increment determines the correction value at the current time. This allows the feedback correction to be continuously updated according to the dynamic changes in the concentration deviation, correcting the residual deviation based on feedforward compensation and ensuring that the concentration is accurately and stably maintained at the target value.

[0053] Step S204: The feedforward compensation amount and the feedback correction amount are superimposed to obtain the control output amount.

[0054] Specifically, the control output is obtained by superimposing the feedforward compensation and the feedback correction, so that the output contains both predictive compensation and corrective compensation components. This retains the feedforward's active suppression of evaporative cooling disturbances and integrates the feedback's continuous correction of residual deviations, thereby achieving the dual goals of constant liquid temperature and accurate concentration in a single control command.

[0055] Step S205: The control output is transmitted to the thermal management actuator of the liquid raw material. The thermal management actuator is used to adjust the temperature of the liquid raw material. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed, so as to control the concentration of liquid raw material vapor in the mixed vapor.

[0056] The thermal management actuator can be a heating / cooling jacket, which surrounds the bubbling tank and is capable of heating power. Active heating or cooling.

[0057] Specifically, by converting the superimposed control output into a drive signal and transmitting it to the heating / cooling jacket surrounding the bubbling tank, the heating / cooling jacket actively adjusts the temperature of the liquid raw material according to the drive signal. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed, thereby controlling the concentration of liquid raw material vapor in the mixed vapor. Thus, the calculation result after superimposing the feedforward compensation and feedback correction is transformed into a physical adjustment action on the temperature of the liquid raw material, realizing the final execution of the control command.

[0058] The vapor concentration stabilization control method provided in this embodiment establishes a heat balance model that includes evaporation heat absorption, ambient heat exchange, and liquid heat capacity. Based on this model, it calculates the feedforward compensation amount in real time. This proactively outputs compensation heat before the liquid temperature drops due to evaporation cooling, solving the problem in existing technologies where feedback control cannot timely suppress liquid temperature drop and concentration drift due to heating lag. The feedforward compensation amount is calculated and output before the temperature drops, also addressing the fundamental defect of feedback control that cannot predict in advance due to reliance on deviation signals. Furthermore, by superimposing the feedforward compensation amount and the feedback correction amount and transmitting them to the thermal management actuator, the feedback correction amount only needs to correct the small residual after feedforward compensation, avoiding overshoot, oscillation, and concentration deterioration caused by simply increasing the heating power or carrier gas flow rate. The thermal management actuator regulates the temperature of the liquid feedstock, thereby changing the saturated vapor pressure of the liquid feedstock and controlling the concentration of liquid feedstock vapor in the mixed vapor, thus achieving constant liquid temperature and long-term stability of the outlet vapor concentration.

[0059] This embodiment provides a vapor concentration stabilization control method, which can be used in the aforementioned vapor concentration stabilization control system to control the concentration of raw material vapor in the mixed vapor formed by the evaporation of liquid raw materials carried by the carrier gas. Figure 3 This is a flowchart of a vapor concentration stabilization control method according to an embodiment of the present invention, such as... Figure 3 As shown, the process includes the following steps: Step S301: Obtain the current temperature and remaining mass of the liquid feedstock, as well as the molar flow rate of the carrier gas. For details, please refer to [link to relevant documentation]. Figure 2Step S201 of the illustrated embodiment will not be described again here.

[0060] Step S302: Based on the current temperature and current remaining mass of the liquid feedstock, and the molar flow rate of the carrier gas, calculate the feedforward compensation amount to compensate for the temperature change caused by the evaporation heat absorption of the liquid feedstock according to the pre-established heat balance model. The heat balance model is established based on the heat conservation relationship of the liquid feedstock. The heat conservation relationship consists of the balance between the change of internal energy of the liquid feedstock, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount. The specific heat capacity, latent heat of vaporization, heat transfer coefficient, carrier gas flow rate, saturated vapor pressure, and total outlet pressure of the liquid feedstock are used as characteristic parameters.

[0061] Specifically, step S302 includes: Step a: Obtain the latent heat of vaporization and molar mass of the liquid feedstock; determine the saturated vapor pressure of the liquid feedstock at the current temperature based on the current temperature, latent heat of vaporization, and molar mass; determine the molar fraction of feedstock vapor in the mixed vapor based on the saturated vapor pressure and the total pressure at the mixed vapor output point; calculate the current evaporation mass flow rate of the liquid feedstock based on the molar flow rate and molar fraction of the carrier gas; calculate the heat carried away by evaporation based on the current evaporation mass flow rate and latent heat of vaporization; calculate the heat transferred to the environment based on the difference between the current temperature and the ambient temperature and the preset heat transfer coefficient; when the temperature change rate of the liquid feedstock is zero, calculate the feedforward compensation amount based on the heat carried away by evaporation and the heat transferred to the environment.

[0062] Specifically, during system operation, the controller first acquires the latent heat of vaporization and molar mass of the liquid raw material pre-stored therein. It then calculates the saturated vapor pressure at the current temperature by combining the real-time temperature collected by the liquid temperature sensor and the total pressure at the outlet pipe of the mixed vapor collected by the pressure sensor, along with the latent heat of vaporization and molar mass. The molar fraction of the raw material vapor in the mixed gas is then determined by the ratio of the saturated vapor pressure to the total pressure. Simultaneously, the controller acquires the current flow rate of the carrier gas set and detected by the mass flow controller. This flow rate is multiplied by the molar fraction to obtain the current evaporation mass flow rate, which is then multiplied by the latent heat of vaporization to calculate the heat carried away by evaporation. The difference between the current temperature and the ambient temperature collected by the ambient temperature sensor, along with the heat transfer coefficient preset in the controller, is used to calculate the ambient heat transferred in. Finally, the controller subtracts the ambient heat transferred in from the heat carried away by evaporation, and adds the product of the current remaining mass collected by the liquid level / mass sensor and the specific heat capacity and temperature change rate of the liquid raw material to comprehensively solve for the feedforward compensation amount. This compensation amount can be updated in real time according to changes in operating conditions and is actively output to the heating / cooling jacket before the actual temperature drop.

[0063] In one optional implementation, the formula for calculating the feedforward compensation amount is as follows: (5).

[0064] The objective of this embodiment is to maintain the current temperature of the liquid feedstock. Constant, that is ,but The required heating power feedforward compensation amount can be obtained from equation (1). for: (6); In an optional implementation, substituting equation (3) into equation (6) yields the feedforward compensation amount that can be calculated in real time, i.e., the feedforward compensation power: (7); in, This is the feedforward compensation amount, representing the feedforward power calculated in real time. To remove heat through evaporation, Heat is transferred to the environment. For the current remaining mass, The specific heat capacity of the liquid raw material. The current temperature of the liquid raw material. This is the rate of temperature change of the liquid raw material. When the current temperature of the liquid raw material deviates from the set temperature, the rate of temperature change is determined based on the difference between the set temperature and the current temperature. The molar flow rate of the carrier gas. Indicates the type of carrier gas (e.g., nitrogen). It is the saturated vapor pressure. This is the total pressure at the outlet of the mixed vapor. The latent heat of vaporization of liquid feedstock, The heat transfer coefficient is... For ambient temperature, At the current sampling time, This represents the temperature difference as a function of the sampling time.

[0065] It should be noted that the current temperature of the liquid raw material... and ambient temperature Both change over time, thus ensuring that the dimensions on the left and right sides of formulas (5) to (7) are consistent.

[0066] heat transfer coefficient This can be obtained through online identification experiments: In the absence of evaporation (without nitrogen flow), a known step heating power is applied to the liquid, and the liquid temperature change curve is measured. The temperature rise is then calculated using the time constant and steady-state temperature rise. ,in, This represents a steady-state temperature rise. The online identification experiment steps are as follows: 1. Steady-state condition preparation: Turn off the nitrogen mass flow controller (nitrogen molar flow rate). (At this point, there is no endothermic evaporation), so heat the formic acid liquid in the bubbling tank to a stable room temperature to ensure the initial temperature of the liquid. Compared with the initial ambient temperature Achieving thermal equilibrium (i.e., stable temperature with minimal temperature difference).

[0067] 2. Apply step heating: Record the liquid temperature and ambient temperature at this time. Suddenly apply a fixed, known step heating power signal (e.g., 100W output from the heating mantle).

[0068] 3. Record transient response curves: continuously collect liquid temperature data with a sampling period of 0.1s to 1s. The process of change.

[0069] 4. Calculate the heat transfer coefficient : When a new steady state is reached, record the steady-state liquid temperature. With steady-state ambient temperature ; Calculate the final steady-state temperature rise: (8); Substituting into the heat balance formula under no-evaporation conditions: (9); Therefore, the heat transfer coefficient can be obtained by inverse solving: (10).

[0070] in, Given a known step heating power, a fixed electric heating power (e.g., 100W) is applied to the bubbling tank in the identification experiment to determine the heat transfer coefficient.

[0071] 5. Industrial control limitations: To ensure that no severe overshoot is introduced during online identification, the heating step should not be too large, and it is usually advisable to achieve a steady-state temperature rise of 3℃~5℃.

[0072] Step S303: When the change in the current remaining mass exceeds a preset mass threshold, and / or the change in the ambient temperature exceeds a preset temperature threshold, update at least one parameter in the thermal balance model.

[0073] In one alternative implementation, updating at least one parameter in the thermal equilibrium model includes: re-identifying the heat transfer coefficient in the thermal equilibrium model; and updating the specific heat capacity of the liquid feedstock and the current remaining mass of the liquid feedstock.

[0074] Specifically, during system operation, the controller continuously acquires the current remaining mass of the liquid raw material from the real-time data collected by the level / mass sensor and the ambient temperature from the real-time data collected by the ambient temperature sensor. It compares the current remaining mass with the initial remaining mass or the remaining mass at the previous moment to calculate its change, and simultaneously compares the current ambient temperature with the initial ambient temperature or the ambient temperature at the previous moment to calculate its change. When the change in the current remaining mass exceeds a preset mass threshold, and / or when the change in the ambient temperature exceeds a preset temperature threshold, the controller triggers a model update operation. This re-identifies and updates the heat transfer coefficient preset in the controller, updates the specific heat capacity of the liquid raw material and the current remaining mass, ensuring that the relevant parameters in the heat balance model match the changed actual operating conditions. The preset mass threshold and preset temperature threshold can be set according to the actual operating conditions, for example: Preset quality threshold: An update is triggered when the quality decreases by 5% to 10%. Preset temperature threshold: Update is triggered when the ambient temperature changes by ±2℃ to ±5℃.

[0075] Step S304: Obtain the current concentration of the raw material vapor in the mixed steam, and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration.

[0076] Specifically, step S304 includes: Step b: Calculate the concentration deviation between the current concentration and the target concentration; based on the concentration deviation, use a closed-loop control algorithm to calculate the feedback correction amount.

[0077] In one optional implementation, the closed-loop control algorithm is an incremental PID algorithm; based on the concentration deviation, the feedback correction amount is calculated using the closed-loop control algorithm, including: obtaining the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation at the two previous sampling times; calculating the increment of the feedback correction amount using the incremental PID algorithm based on the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation at the two previous sampling times; and determining the feedback correction amount at the current sampling time based on the increment of the feedback correction amount.

[0078] Specifically, in each sampling cycle, the controller acquires the current concentration detected in real time by the concentration sensor, subtracts it from the target concentration to obtain the concentration deviation at the current sampling time, and stores the concentration deviations of the current and previous sampling times internally. When the next sampling time arrives, the controller can obtain the concentration deviations of the previous two sampling times. Based on the concentration deviations of the current, previous, and previous two sampling times, the controller calculates the increment of the feedback correction amount at the current time according to the internally preset incremental PID algorithm. Then, the controller adds this increment to the feedback correction amount at the previous time to determine the feedback correction amount at the current time, and outputs it to the superposition module to be superimposed with the current feedforward compensation amount. This allows the feedback correction amount to be continuously updated with the dynamic changes in the concentration deviation, and corrects the residual deviation based on the feedforward compensation.

[0079] It should be noted that the incremental PID algorithm in this embodiment has a relatively long integral time constant and a relatively small proportional gain, and its main function is only to suppress environmental temperature interference. Provided the feedforward model is correct, even if the PID output temporarily saturates (reaches the upper or lower limit), the system can still maintain a basically constant output thanks to the feedforward input.

[0080] In one optional implementation, when the absolute value of the concentration deviation is less than a preset threshold, the feedback correction amount is zero or remains unchanged.

[0081] In one optional implementation, the formula for calculating the feedback correction amount is as follows: (11); in, For feedback correction amount, , and These represent the proportional coefficient, integral coefficient, and derivative coefficient of the incremental PID algorithm, respectively. This represents the concentration deviation at the current sampling time. This represents the concentration deviation at the previous sampling time, which is the first sampling time before the current time. This represents the concentration difference between the previous two sampling times, where the previous two sampling times are the second sampling time before the current time. The sampling period.

[0082] Step S305: The feedforward compensation amount and the feedback correction amount are superimposed to obtain the control output amount.

[0083] Specifically, the controlled output is the total heating power, expressed by the following formula: (12).

[0084] Step S306: The control output is transmitted to the thermal management actuator of the liquid raw material. The thermal management actuator is used to adjust the temperature of the liquid raw material. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed, so as to control the concentration of liquid raw material vapor in the mixed vapor.

[0085] Specifically, step S306 includes: Step c: Generate a drive signal based on the control output; transmit the drive signal to the thermal management actuator, and use the thermal management actuator to respond to the drive signal and adjust the temperature of the liquid raw material.

[0086] After superimposing the feedforward compensation and feedback correction to obtain the control output, the controller generates a corresponding drive signal (such as a voltage signal, current signal, or PWM (Pulse Width Modulation) signal) based on the control output and transmits the drive signal to the heating / cooling jacket surrounding the bubbling tank. Upon receiving the drive signal, the heating / cooling jacket adjusts the temperature of the liquid raw material with the corresponding heating or cooling power, thereby converting the control output into a physical adjustment action on the temperature of the liquid raw material, realizing the final execution of feedforward compensation and feedback correction. At the same time, the liquid temperature sensor continuously detects the adjusted temperature of the liquid raw material and transmits it back to the controller, forming the data basis for the next control cycle.

[0087] It should be noted that if a heating jacket is unavailable, the molar flow rate of the carrier gas, i.e., the molar flow rate of nitrogen, can be adjusted using a feedforward model. To balance evaporative cooling: setting The required molar flow rate of nitrogen can be calculated by back-calculating from equation (1). However, this method will also change the vapor carryover rate, making it suitable for scenarios where the concentration can be changed only slightly. Heating is the preferred option in this case.

[0088] When the current remaining mass of the liquid If the temperature decreases significantly or the ambient temperature changes beyond a threshold, the heat transfer coefficient can be re-identified online. Or update the liquid heat capacity change term. To maintain the accuracy of the feedforward compensation.

[0089] The vapor concentration stabilization control method provided in this embodiment establishes a dynamic thermal balance model of the formic acid bubbling tank, which includes evaporation heat absorption, ambient heat exchange, and liquid heat capacity. Based on this model, a real-time feedforward heating power formula is derived. The feedforward control is combined with concentration PID feedback to form a dual-layer control structure, achieving the dual objectives of constant liquid temperature and accurate concentration. It can actively counteract the evaporation cooling effect, maintain a constant formic acid liquid temperature, and thus achieve long-term stable feedforward-feedback composite control.

[0090] As one or more specific application embodiments of the present invention, combined with Figure 4 The steam concentration stabilization control method provided by the present invention will be further described in detail, such as... Figure 4 As shown, the specific process is as follows: S1. Initialization and parameter calibration: Input physical property constant: specific heat capacity of liquid raw material Latent heat of vaporization of liquid feedstock and the current remaining mass of liquid feedstock .

[0091] The heat transfer coefficient was determined through identification experiments. .

[0092] Set target concentration The target liquid temperature can be calculated from the process formula. ,according to , It is the saturated vapor pressure of the liquid raw material at a set temperature.

[0093] S2. Real-time data acquisition: With sampling period (e.g., 1 second) Data collection: Current temperature of liquid raw material Ambient temperature Current remaining mass of liquid Molar flow rate of nitrogen Total pressure Export concentration .

[0094] S3. Feedforward power calculation: According to equation (7), the current temperature of the liquid raw material under the current operating conditions is calculated. Constant required feedforward power .when Deviation from set temperature At that time, in the feedforward model Item changed This is to avoid conflicts between feedback correction and feedforward.

[0095] S4. Feedback Correction Calculation: Concentration deviation at the current sampling time As input, an incremental PID algorithm is used to calculate the feedback heating power correction amount, i.e., the feedback correction amount. : (11); The PID parameters can be conservatively tuned based on the equivalent controlled object after feedforward compensation (close to unity gain).

[0096] S5. Total Heating Power Calculation: (12).

[0097] S6. Output Execution: [This will...] Apply to the heating mantle, wait for the next cycle, and return to step S2.

[0098] S7. Optional adaptive adjustment: when the current remaining mass of the liquid... If the temperature decreases significantly or the ambient temperature changes beyond a threshold, the heat transfer coefficient can be re-identified online. Alternatively, update the liquid heat capacity change term to maintain the accuracy of the feedforward compensation.

[0099] The application examples of the steam concentration stabilization control method provided by this invention are as follows: Under the conditions of initial liquid temperature 25℃, ambient temperature 25℃, formic acid mass 15kg, N2 molar flow rate 0.446mol / s (10slm), and total pressure 1100mbar, a 60-minute comparative experiment was conducted using three control strategies.

[0100] The results show that: As shown in Figures 5(a) and 5(b), without control (heating power is constant at 0), the liquid temperature drops to approximately 21.2℃, and the outlet concentration decreases from 5.19% to approximately 4.3%, indicating severe drift. Under pure PID feedback control for 60 minutes, the temperature and concentration can be brought back somewhat, but the final liquid temperature drops to approximately 22.3℃, and the concentration drops to approximately 4.54%. When using the feedforward + feedback control of this invention, the liquid temperature stabilized at approximately 24.1℃ and the concentration stabilized at approximately 4.96%. The results show that the vapor concentration stabilization control method provided by this invention resulted in a liquid temperature decrease of only 0.9℃ and a concentration decrease of only 0.23 percentage points within 60 minutes, significantly better than no control (decreases of 3.8℃ and 0.89 percentage points) and pure PID feedback (decreases of 2.7℃ and 0.65 percentage points), verifying the superiority of this invention in maintaining constant liquid temperature and stable concentration.

[0101] Specifically, Figure 5(a) shows the outlet concentration change curves under three control strategies over 60 minutes. Without control, the concentration continuously decreased from the initial 5.19% to approximately 4.3%, showing severe drift. Under pure PID feedback control, the concentration decreased from 5.19% to approximately 4.54%, showing some improvement but still a significant decrease. However, when using the feedforward + feedback control of this invention, the concentration decreased from 5.19% to approximately 4.96%, with the smallest fluctuation range and the smoothest curve, verifying the superiority of this invention in suppressing concentration drift.

[0102] Figure 5(b) shows the liquid temperature change curves under three control strategies over 60 minutes. Without control, the liquid temperature continuously decreased from the initial 25°C to approximately 21.2°C, a decrease of 3.8°C; under pure PID feedback control, the liquid temperature decreased from 25°C to approximately 22.3°C, a decrease of 2.7°C; while with the feedforward + feedback control of this invention, the liquid temperature decreased from 25°C to approximately 24.1°C, a decrease of only 0.9°C.

[0103] The results show that the present invention can actively predict and compensate for the evaporative cooling effect, and control the liquid temperature fluctuation within a minimum range within 60 minutes, thus fundamentally ensuring the long-term stability of the outlet concentration.

[0104] This embodiment also provides a vapor concentration stabilization control device for implementing the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0105] This embodiment provides a vapor concentration stabilization control device for controlling the concentration of raw material vapor in the mixed vapor formed by the evaporation of liquid raw materials carried by the carrier gas, such as... Figure 6 As shown, it includes: The data acquisition module 601 is used to acquire the current temperature and current remaining mass of the liquid raw material, as well as the molar flow rate of the carrier gas; The feedforward calculation module 602 is used to calculate the feedforward compensation amount to compensate for the temperature change of the liquid feedstock due to evaporation heat absorption, based on the current temperature and current remaining mass of the liquid feedstock and the molar flow rate of the carrier gas, according to a pre-established heat balance model. The heat balance model is established based on the heat conservation relationship of the liquid feedstock, which consists of the balance between the change of internal energy of the liquid feedstock, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount, and uses the specific heat capacity, latent heat of vaporization, heat transfer coefficient, carrier gas flow rate, saturated vapor pressure, and total outlet pressure of the liquid feedstock as characteristic parameters. The feedback calculation module 603 is used to obtain the current concentration of the raw material vapor in the mixed vapor and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration. The superposition module 604 is used to superimpose the feedforward compensation amount and the feedback correction amount to obtain the control output amount; The transmission module 605 is used to transmit the control output to the thermal management actuator of the liquid raw material. The thermal management actuator adjusts the temperature of the liquid raw material and changes the saturated vapor pressure of the liquid raw material by adjusting the temperature, so as to control the concentration of liquid raw material vapor in the mixed vapor.

[0106] In some alternative implementations, the feedforward computing module 602 includes: The feedforward compensation calculation unit is used to obtain the latent heat of vaporization and molar mass of the liquid feedstock; determine the saturated vapor pressure of the liquid feedstock at the current temperature based on the current temperature, latent heat of vaporization, and molar mass; determine the molar fraction of feedstock vapor in the mixed vapor based on the saturated vapor pressure and the total pressure at the mixed vapor output; calculate the current evaporation mass flow rate of the liquid feedstock based on the molar flow rate and molar fraction of the carrier gas; calculate the heat carried away by evaporation based on the current evaporation mass flow rate and latent heat of vaporization; calculate the heat transferred to the environment based on the difference between the current temperature and the ambient temperature and the preset heat transfer coefficient; and calculate the feedforward compensation amount based on the heat carried away by evaporation and the heat transferred to the environment when the temperature change rate of the liquid feedstock is zero.

[0107] In one optional implementation, the formula for calculating the feedforward compensation amount is as follows: ; in, This is the feedforward compensation amount, representing the feedforward power calculated in real time. To remove heat through evaporation, Heat is transferred to the environment. The current temperature of the liquid raw material. The molar flow rate of the carrier gas. Indicates the type of carrier gas. It is the saturated vapor pressure. This is the total pressure at the outlet of the mixed vapor. The latent heat of vaporization of liquid feedstock, The heat transfer coefficient is... For ambient temperature, At the current sampling time, This represents the temperature difference as a function of the sampling time.

[0108] In some alternative embodiments, the device further includes: The model parameter update module is used to update at least one parameter in the thermal balance model when the change in the current remaining mass exceeds a preset mass threshold, and / or the change in the ambient temperature exceeds a preset temperature threshold.

[0109] In one optional implementation, the model parameter update module includes: Heat transfer coefficient identification unit, used to re-identify the heat transfer coefficient in the heat balance model; The hot melt item update unit is used to update the specific heat capacity and current remaining mass of the liquid raw material.

[0110] In one alternative implementation, the feedback calculation module 603 includes: The concentration deviation calculation unit is used to calculate the concentration deviation between the current concentration and the target concentration; The closed-loop control unit is used to calculate the feedback correction amount based on the concentration deviation using a closed-loop control algorithm.

[0111] In one optional implementation, the closed-loop control algorithm is an incremental PID algorithm; the closed-loop control unit includes: The deviation acquisition subunit is used to acquire the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation between the previous two sampling times. The incremental calculation subunit is used to calculate the increment of the feedback correction amount according to the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation at the previous two sampling times, using an incremental PID algorithm. The feedback correction calculation subunit is used to determine the feedback correction amount at the current sampling time based on the increment of the feedback correction amount.

[0112] In one optional implementation, when the absolute value of the concentration deviation is less than a preset threshold, the feedback correction amount is zero or remains unchanged.

[0113] In one optional implementation, the formula for calculating the feedback correction amount is as follows: ; in, For feedback correction amount, , and These represent the proportional coefficient, integral coefficient, and derivative coefficient of the incremental PID algorithm, respectively. This represents the concentration deviation at the current sampling time. This represents the concentration deviation at the previous sampling time, which is the first sampling time before the current time. This represents the concentration difference between the previous two sampling times, where the previous two sampling times are the second sampling time before the current time. The sampling period.

[0114] In one alternative implementation, the transmission module 605 includes: A drive signal generation unit is used to generate drive signals based on control output quantities. The output and temperature control unit is used to transmit the drive signal to the thermal management actuator, which then responds to the drive signal to adjust the temperature of the liquid raw material.

[0115] The steam concentration stabilization control device provided in this embodiment of the invention can execute the steam concentration stabilization control method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects for executing the method. Further functional descriptions of the various modules and units described above are the same as in the corresponding embodiments described above, and will not be repeated here.

[0116] Figure 7 This is a schematic diagram of an electronic device provided in an embodiment of the present invention. It illustrates a structural schematic diagram suitable for implementing the electronic device in this embodiment. The electronic device may include a processor (e.g., a central processing unit, a graphics processing unit, etc.) 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory 702 or a program loaded from a memory 708 into a random access memory 703. The read-only memory may be a ROM, and the random access memory may be RAM. The random access memory 703 also stores various programs and data required for the operation of the electronic device. The processor 701, the read-only memory 702, and the random access memory 703 are interconnected via a bus 704. An input / output interface 705 is also connected to the bus 704.

[0117] Typically, the following devices can be connected to the input / output interface 705: input devices 706 including, for example, touchscreens, touchpads, keyboards, mice, cameras, microphones, accelerometers, gyroscopes, etc.; output devices 707 including, for example, liquid crystal displays (LCDs), speakers, vibrators, etc.; and memory devices 708 including, for example, magnetic tapes, hard disks, etc. Although Figure 7 Electronic devices with various devices are shown, but it should be understood that it is not required to implement or have all of the devices shown, and more or fewer devices may be implemented or have instead.

[0118] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a non-transitory computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be mounted from memory 708 (the memory being magnetic tape, hard disk, etc.) or from read-only memory 702. When the computer program is executed by processor 701, it performs the functions defined in the cooperative control method of etching apparatus and spectral imager according to embodiments of the present invention.

[0119] Figure 7 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0120] This invention also provides a computer-readable storage medium. The methods described above according to embodiments of the invention can be implemented in hardware or firmware, or implemented as computer code that can be recorded on a storage medium, or implemented as computer code downloaded via a network and originally stored on a remote storage medium or a non-transitory machine-readable storage medium and then stored on a local storage medium. Thus, the methods described herein can be processed by software stored on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. The storage medium can be a magnetic disk, optical disk, read-only memory, random access memory, flash memory, hard disk, or solid-state drive, etc.; further, the storage medium can also include combinations of the above types of memory. It is understood that computers, processors, microprocessor controllers, or programmable hardware include storage components capable of storing or receiving software or computer code. When the software or computer code is accessed and executed by the computer, processor, or hardware, the vapor concentration stabilization control method shown in the above embodiments is implemented.

[0121] A portion of this invention can be applied as a computer program product, such as computer program instructions, which, when executed by a computer, can invoke or provide the methods and / or technical solutions according to the invention through the operation of the computer. Those skilled in the art will understand that the forms in which computer program instructions exist in a computer-readable medium include, but are not limited to, source files, executable files, installation package files, etc. Correspondingly, the ways in which computer program instructions are executed by a computer include, but are not limited to: the computer directly executing the instructions, or the computer compiling the instructions and then executing the corresponding compiled program, or the computer reading and executing the instructions, or the computer reading and installing the instructions and then executing the corresponding installed program. Here, the computer-readable medium can be any available computer-readable storage medium or communication medium accessible to a computer.

[0122] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A method for stabilizing and controlling steam concentration, characterized in that, The method for controlling the concentration of feedstock vapor in a mixed vapor formed by the evaporation of liquid feedstock carried by a carrier gas includes: Obtain the current temperature and current remaining mass of the liquid feedstock, as well as the molar flow rate of the carrier gas; Based on the current temperature and remaining mass of the liquid feedstock, and the molar flow rate of the carrier gas, a feedforward compensation amount is calculated according to a pre-established heat balance model to compensate for the temperature change caused by the evaporation heat absorption of the liquid feedstock. The heat balance model is established based on the heat conservation relationship of the liquid feedstock, which is composed of the balance between the change in the internal energy of the liquid feedstock, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount, and uses the specific heat capacity, latent heat of vaporization, heat transfer coefficient, carrier gas flow rate, saturated vapor pressure, and total outlet pressure of the liquid feedstock as characteristic parameters. Obtain the current concentration of the raw material vapor in the mixed vapor, and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration; The control output is obtained by superimposing the feedforward compensation amount and the feedback correction amount. The control output is transmitted to the thermal management actuator of the liquid raw material, and the temperature of the liquid raw material is adjusted by the thermal management actuator. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed, so as to control the concentration of liquid raw material vapor in the mixed vapor.

2. The method according to claim 1, characterized in that, The feedforward compensation amount, calculated based on a pre-established heat balance model to compensate for the temperature change caused by the evaporation and heat absorption of the liquid raw material, includes: Obtain the latent heat of vaporization and molar mass of the liquid raw material; Determine the saturated vapor pressure of the liquid feedstock at the current temperature based on the current temperature, the latent heat of vaporization, and the molar mass; The mole fraction of the raw material vapor in the mixed vapor is determined based on the saturated vapor pressure and the total pressure at the outlet of the mixed vapor. Calculate the current evaporation mass flow rate of the liquid feedstock based on the molar flow rate and molar fraction of the carrier gas; Calculate the heat carried away by evaporation based on the current evaporation mass flow rate and the latent heat of vaporization; The heat transferred to the environment is calculated based on the difference between the current temperature and the ambient temperature and the preset heat transfer coefficient. When the temperature change rate of the liquid raw material is zero, the feedforward compensation amount is calculated based on the heat removed by evaporation and the heat transferred in from the environment.

3. The method according to claim 2, characterized in that, The formula for calculating the feedforward compensation amount is as follows: ； in, This is the feedforward compensation amount, representing the feedforward power calculated in real time. To remove heat through evaporation, Heat is transferred to the environment. The current temperature of the liquid raw material. The molar flow rate of the carrier gas. Indicates the type of carrier gas. It is the saturated vapor pressure. This is the total pressure at the outlet of the mixed vapor. The latent heat of vaporization of liquid feedstock, The heat transfer coefficient is... For ambient temperature, At the current sampling time, This represents the temperature difference as a function of the sampling time.

4. The method according to claim 2, characterized in that, The method further includes: When the change in the current remaining mass exceeds a preset mass threshold, and / or when the change in the ambient temperature exceeds a preset temperature threshold, at least one parameter in the thermal balance model is updated.

5. The method according to claim 4, characterized in that, Updating at least one parameter in the thermal equilibrium model includes: Re-identify the heat transfer coefficients in the aforementioned thermal equilibrium model; Update the specific heat capacity of the liquid feedstock and the current remaining mass of the liquid feedstock.

6. The method according to claim 1, characterized in that, The feedback correction amount is calculated based on the concentration deviation between the current concentration and the target concentration, including: Calculate the concentration deviation between the current concentration and the target concentration; Based on the concentration deviation, the feedback correction amount is calculated using a closed-loop control algorithm.

7. The method according to claim 6, characterized in that, The closed-loop control algorithm is an incremental PID algorithm; Based on the concentration deviation, the feedback correction amount is calculated using a closed-loop control algorithm, including: Obtain the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation between the two previous sampling times; Based on the concentration deviation at the current sampling time, the concentration deviation at the previous sampling time, and the concentration deviation between the two previous sampling times, the increment of the feedback correction is calculated using an incremental PID algorithm. The feedback correction amount at the current sampling time is determined based on the increment of the feedback correction amount.

8. The method according to claim 7, characterized in that, When the absolute value of the concentration deviation is less than a preset threshold, the feedback correction amount is zero or remains unchanged.

9. The method according to claim 7, characterized in that, The formula for calculating the feedback correction amount is as follows: ； in, For feedback correction amount, , and These represent the proportional coefficient, integral coefficient, and derivative coefficient of the incremental PID algorithm, respectively. This represents the concentration deviation at the current sampling time. This represents the concentration deviation at the previous sampling time, where the previous sampling time is the first sampling time before the current time. The concentration difference is the difference between the previous two sampling times, where the previous two sampling times are the second sampling time before the current time. The sampling period.

10. The method according to claim 1, characterized in that, The control output is transmitted to the thermal management actuator of the liquid raw material, and the temperature of the liquid raw material is adjusted by the thermal management actuator, including: A drive signal is generated based on the control output; The drive signal is transmitted to the thermal management actuator, which responds to the drive signal to adjust the temperature of the liquid raw material.

11. A steam concentration stabilization control system, characterized in that, The system is used to control the concentration of feedstock vapor in the mixed vapor formed by the evaporation of liquid feedstock carried by the carrier gas. The system includes: A bubbling tank is used to contain liquid raw materials and is equipped with a carrier gas inlet pipe and a mixed vapor outlet pipe. A liquid temperature sensor, immersed in the liquid raw material, is used to detect the temperature of the liquid raw material; An ambient temperature sensor is installed on the outside of the bubbling tank to detect the ambient temperature; A level / mass sensor is installed on the tank body of the bubbling tank to detect the remaining mass of the liquid raw material; A heating / cooling jacket, surrounding the bubbling tank, is used to regulate the temperature of the liquid raw material; A concentration sensor is installed at the outlet pipe of the mixed steam to detect the concentration of the raw material steam in the mixed steam. A pressure sensor is installed at the outlet pipe of the mixed steam to detect the total pressure at the outlet pipe of the mixed steam. The controller is communicatively connected to the liquid temperature sensor, the ambient temperature sensor, the liquid level / mass sensor, the concentration sensor, the pressure sensor, and the heating / cooling jacket. The controller is used to execute the vapor concentration stabilization control method according to any one of claims 1 to 10.

12. A steam concentration stabilization control device, characterized in that, The device is used to control the concentration of feedstock vapor in the mixed vapor formed by the evaporation of liquid feedstock carried by the carrier gas. The device includes: The data acquisition module is used to acquire the current temperature and current remaining mass of the liquid raw material, as well as the molar flow rate of the carrier gas; The feedforward calculation module is used to calculate the feedforward compensation amount to compensate for the temperature change of the liquid raw material caused by evaporation heat absorption, based on the current temperature and current remaining mass of the liquid raw material and the molar flow rate of the carrier gas, according to a pre-established heat balance model. The heat balance model is established based on the heat conservation relationship of the liquid raw material, which is composed of the balance between the change of internal energy of the liquid raw material, the heat carried away by evaporation, the heat transferred from the environment, and the external heating amount, and uses the specific heat capacity, latent heat of vaporization, heat transfer coefficient, carrier gas flow rate, saturated vapor pressure, and total outlet pressure of the liquid raw material as characteristic parameters. The feedback calculation module is used to obtain the current concentration of the raw material vapor in the mixed vapor and calculate the feedback correction amount based on the concentration deviation between the current concentration and the target concentration. The superposition module is used to superimpose the feedforward compensation amount and the feedback correction amount to obtain the control output amount; The transmission module is used to transmit the control output to the thermal management actuator of the liquid raw material, and the thermal management actuator is used to adjust the temperature of the liquid raw material. By adjusting the temperature of the liquid raw material, the saturated vapor pressure of the liquid raw material is changed, so as to control the concentration of liquid raw material vapor in the mixed vapor.

13. An electronic device, characterized in that, include: A memory and a processor are communicatively connected, the memory storing computer instructions, and the processor executing the computer instructions to perform the vapor concentration stabilization control method according to any one of claims 1 to 10.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions for causing the computer to perform the vapor concentration stabilization control method according to any one of claims 1 to 10.

15. A computer program product, characterized in that, Includes computer instructions for causing a computer to execute the vapor concentration stabilization control method according to any one of claims 1 to 10.

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