Closed-loop control method for drying process parameters of oven

Abstract

The invention discloses a closed-loop control method for drying process parameters of an oven, which comprises air speed closed-loop regulation and NMP closed-loop regulation, the NMP closed-loop regulation comprises exhaust ratio closed-loop regulation and exhaust air rate closed-loop regulation, and the air speed closed-loop regulation, the exhaust ratio closed-loop regulation and the exhaust air rate closed-loop regulation comprise three sub-regulation systems, namely an air speed closed-loop regulation system, an exhaust ratio closed-loop regulation system and an exhaust air rate closed-loop regulation system, the closed-loop adjustment of the NMP is realized through the combined action of the closed-loop adjustment of the exhaust ratio and the closed-loop adjustment of the exhaust air rate. According to the closed-loop control method, the equipment debugging work can be efficiently completed without shutdown, the response speed is high, the adjustment precision is good, the intelligent degree is high, and the dependence on manual debugging experience in the debugging process is greatly reduced.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing technology, and in particular to a closed-loop control method for oven drying process parameters. Background Art

[0002] Most oven equipment currently uses manual debugging methods for adjustment, requiring on-site operators to adjust after shutdown or in real time during the production process. If the relevant parameters are adjusted after shutdown, the debugging effect must be verified by re-production. If an abnormality occurs again, the equipment must be shut down for debugging again. In the long run, this not only seriously affects the production cycle but also easily leads to a large amount of waste of raw materials. Real-time debugging during the working process is subject to interference from human factors, slow response time and processing speed for abnormal parameters, and the debugging effect is extremely dependent on the experience of the on-site debugging personnel. It is difficult to guarantee the quality of the products produced after debugging. If the abnormality is not effectively handled, it is very easy to cause batch scrapping accidents. In addition, oven equipment that has adopted the closed-loop adjustment method has a relatively simple control method. A control system can only respond to and adjust one variable. There is a lack of interlocking between systems, which can easily cause control conflicts. Therefore, the variables that can be adjusted by the entire system are usually limited, making it difficult to achieve closed-loop control of the entire machine.

[0003] Therefore, it is necessary to provide a closed-loop control method for oven drying process parameters to solve the above problems. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention provides a closed-loop control method for oven drying process parameters, which can efficiently complete equipment debugging work without stopping the equipment. It has a fast response speed, good adjustment accuracy, and a high degree of intelligence, which greatly reduces the dependence on manual debugging experience during the debugging process.

[0005] The technical solution adopted by the present invention to solve its technical problem is: A closed-loop control method for oven drying process parameters, including wind speed closed-loop regulation and NMP closed-loop regulation, wherein the NMP closed-loop regulation includes exhaust ratio closed-loop regulation and exhaust volume closed-loop regulation; The wind speed closed-loop regulation monitors the current wind speed of the upper and lower hulls and determines whether it meets the set requirements. The wind frequency is first adjusted and then the wind gate is adjusted to adjust the operating frequency of the fan until the wind speed of the upper and lower hulls meets the set wind speed. The NMP closed-loop regulation is performed by monitoring the NMP concentration sensor to determine whether the set conditions are met, and the exhaust ratio and exhaust volume are adjusted in a closed-loop manner. After the adjustment is completed, the oven concentration is monitored and judged again until the monitored concentration meets the set value, and the closed-loop regulation is completed; The exhaust ratio closed-loop adjustment monitors the current exhaust ratio and determines whether it meets the set requirements. It calculates the exhaust fan's wind frequency and adjusts the fresh air volume based on the negative pressure value required by the oven, thereby affecting the exhaust ratio until the exhaust ratio adjustment requirements are met. The exhaust volume closed-loop regulation monitors the current exhaust volume to determine whether it meets the set requirements, calculates the wind frequency, and controls the exhaust volume by adjusting the exhaust fan wind frequency until the exhaust volume adjustment requirements are met.

[0006] As a further improvement to the above technical solution, in the wind speed closed-loop regulation, when the wind speed of the upper hull and the wind speed of the lower hull do not meet the set values, the following steps are specifically included: S01. Monitor the real-time wind speed of the upper and lower hulls and determine the deviation from the set wind speed; S02. If the wind speed of the upper hull is greater than that of the lower hull, in the upper wind path adjustment control, the current state is that the upper wind gate is fully open. After recalculating the wind frequency of the fan, the upper wind gate opening is adjusted first. If the difference between the real-time wind speed of the upper hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the lower wind path wind gate opening is controlled to assist until the wind speeds of the upper and lower hulls meet the set requirements; S03. If the wind speed of the lower hull is greater than that of the upper hull, in the upper wind path adjustment control, the current state is that the lower wind gate is fully open. After recalculating the wind frequency of the fan, the lower wind gate opening is adjusted first. If the difference between the real-time wind speed of the lower hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the lower wind path wind gate opening is controlled to assist until the wind speeds of the upper and lower hulls meet the set requirements; S04. Re-judge the deviation between the wind speed of the upper hull and the lower hull and the set wind speed. If the requirements are met, the adjustment is completed; if the requirements are not met, repeat steps S01 to S03 until the wind speeds of the upper hull and the lower hull meet the set requirements.

[0007] As a further improvement of the above technical solution, in the S02 step, the downwind path is assisted in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging whether the real-time wind speed of the upper hull meets the set wind speed deviation, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, the downwind gate opening is readjusted until the set conditions are met and the adjustment is completed.

[0008] As a further improvement of the above technical solution, in the S03 step, the downwind path is assisted in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging whether the real-time wind speed of the upper hull meets the set wind speed deviation, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, the downwind gate opening is readjusted until the set conditions are met and the adjustment is completed.

[0009] As a further improvement of the above technical solution, the closed-loop adjustment of the exhaust ratio specifically includes the following steps: S11. Monitor the current exhaust ratio to determine whether it meets the set exhaust ratio requirement. If it meets the set value, the adjustment is completed. If it does not meet the set value, the set frequency is executed and the real-time negative pressure value is determined to meet the wide range of the set negative pressure value. S12. If the real-time negative pressure value does not meet the set requirement, the real-time negative pressure value is judged. If the real-time negative pressure value is greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set lower limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set lower limit of the fresh air gate opening, the fresh air gate opening is reduced. If the fresh air gate opening is greater than the set lower limit of the fresh air gate opening, the total fresh air frequency is reduced. If the real-time negative pressure value is not greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set upper limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set upper limit of the fresh air gate opening, the fresh air gate opening is increased. If the fresh air gate opening is greater than the set upper limit of the fresh air gate opening, the total fresh air frequency is increased. It is judged again whether the real-time negative pressure value is within the set range. If it meets the requirements, proceed to the next step. If it does not meet the requirements, repeat the above steps until the set requirements are met. S13. If the real-time negative pressure value meets the set requirements, the fan frequency is checked to see if it exceeds the upper and lower limits of the set fan frequency. If the fan frequency does not exceed the upper and lower limits of the set fan frequency, the real-time exhaust wind speed is judged to see if it meets the calculated wind speed large range value. If it does not meet the requirements, the S12 step is repeated until the real-time exhaust wind speed meets the calculated wind speed large range value. If it meets the requirements, the real-time exhaust wind speed is judged again to meet the calculated wind speed value. If it meets the requirements, the small fan frequency or the large fan frequency is fine-tuned until the current exhaust ratio meets the set exhaust ratio requirements. If it does not meet the requirements, the small fan frequency or the large fan frequency is roughly adjusted. frequency until the current exhaust ratio meets the set exhaust ratio requirement; if the fan frequency exceeds the upper and lower limits of the set fan frequency, determine whether the real-time fan frequency is less than the lower limit of the set fan frequency. If it meets the set requirements, turn off the exhaust fan, adjust the damper, and then determine the damper closing state. If it meets the requirements, the adjustment is completed. If it does not meet the requirements, determine whether the current exhaust ratio meets the set exhaust ratio requirement. If it meets the requirements, the adjustment is completed. If the fan frequency exceeds the upper and lower limits of the set fan frequency, determine that the real-time fan frequency is not less than the lower limit of the set fan frequency, then adjust the exhaust fan to the maximum frequency and the adjustment is completed.

[0010] As a further improvement of the above technical solution, the maximum power of the exhaust fan is 50HZ.

[0011] As a further improvement of the above technical solution, the closed-loop adjustment of the exhaust volume specifically includes the following steps: S21, determining whether the current exhaust volume meets the set exhaust volume ratio deviation requirement; S22: If the set requirements are met, the adjustment is completed; if the set requirements are not met, the theoretical optimal wind frequency is implemented based on the current actual working conditions; S23, determining whether the current exhaust volume meets the set exhaust volume actual deviation; if not, recalculate the wind frequency and repeat S22 until it meets the requirement, then proceed to the next step; S24, determining whether the current exhaust volume meets the actual air volume. If it meets the requirement, adjust the air frequency down; if it does not meet the requirement, adjust the air frequency up, and then proceed to the next step; S25. Determine whether the current exhaust volume meets the set exhaust volume ratio deviation requirement. If it meets the requirement, the adjustment is completed; if it does not meet the requirement, repeat steps S23-S24 until the exhaust volume adjustment requirement is met.

[0012] As a further improvement of the above technical solution, the NMP closed-loop regulation specifically includes the following steps: S31. Monitor the NMP concentration sensor to determine whether the real-time concentration meets the set value deviation requirement. If it meets the requirement, proceed to the next step; if it does not meet the requirement, repeat the closed-loop adjustment of the exhaust ratio and exhaust volume until the requirement is met; S32, determining whether the real-time concentration meets the set concentration value. If the real-time concentration is not greater than the set concentration, the exhaust ratio is reduced and the next step is performed. If the real-time concentration is not less than the set concentration, the exhaust ratio is increased and the next step is performed. S33, determine whether the detected concentration meets the set concentration value deviation; if it does not meet the concentration requirement, repeat steps S31-S32 until the requirement is met, and if it meets the requirement, complete the closed-loop adjustment.

[0013] The beneficial effects of the present invention are: 1. The closed-loop control system replaces manual parameter adjustment of the equipment. Compared with the traditional adjustment method, the closed-loop control method of the present invention can efficiently complete the equipment debugging work without stopping the production process. It has a fast response speed, good adjustment accuracy, and a high degree of intelligence, which greatly reduces the dependence on manual debugging experience during the debugging process.

[0014] 2. It is universal. The control scheme starts from the structural design and establishes a closed-loop control method for oven drying process parameters based on the conventional oven structure. It is applicable to conventional styles currently used in the market or special-shaped styles that meet the configuration requirements.

[0015] 3. High control accuracy. The subsystem mostly adopts the control method of coarse adjustment first and then fine adjustment. On the one hand, it avoids low control accuracy and poor equipment performance caused by only coarse adjustment. On the other hand, it avoids many adjustment cycles, slow equipment response and impact on product quality caused by only fine adjustment.

[0016] 4. Integrate and interlock the wind speed closed-loop control, exhaust volume closed-loop control, exhaust ratio closed-loop control, oven negative pressure closed-loop control, and NMP concentration closed-loop control, and establish feedback between the sub-control systems and the main control system to build a closed-loop feedback control system for drying adjustment of the entire machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below with reference to the accompanying drawings and examples.

[0018] Figure 1 It is a schematic diagram of the overall flow of the closed-loop control method of the present invention; Figure 2 1 is a flow chart of the closed-loop wind speed regulation of the present invention; Figure 3 It is a schematic flow diagram of the NMP closed-loop regulation of the present invention; Figure 4 Schematic diagram of the closed-loop regulation of the exhaust ratio of the present invention; Figure 5 It is a flow chart of the closed-loop regulation of exhaust volume of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not simply refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation. For example, fixed connection / fixed installation can be selected from screw connection, bolt connection, pin connection, key connection, bonding, mortise and tenon connection, welding, riveting and other methods as needed. For detachable connection, screw connection, bolt connection, threaded connection, snap connection, mortise and tenon connection, Velcro connection and other methods can be selected as needed. The various technical features in the invention can be combined interchangeably without conflicting with each other.

[0020] Reference Figure 1A closed-loop control method for oven drying process parameters includes wind speed closed-loop regulation and NMP closed-loop regulation. The NMP closed-loop regulation includes exhaust ratio closed-loop regulation and exhaust volume closed-loop regulation, which can adjust concentration or humidity, specifically determined by the positive and negative poles of the electrode. The exhaust ratio closed-loop regulation and exhaust volume closed-loop regulation work together to achieve closed-loop regulation of NMP concentration (humidity). At the same time, the wind speed closed-loop control, exhaust volume closed-loop control, exhaust ratio closed-loop control, oven negative pressure closed-loop control, and NMP concentration closed-loop control are integrated and interlocked, and feedback is established between the sub-control systems and the main control system to construct a closed-loop feedback control system for drying regulation of the entire machine. Equipment debugging can be efficiently completed without stopping the machine during production. It has fast response speed, good adjustment accuracy, and a high degree of intelligence, which greatly reduces the dependence on manual debugging experience during the debugging process.

[0021] The wind speed closed-loop regulation monitors the current wind speed of the upper hull and the lower hull and determines whether it meets the set requirements. It first performs coarse adjustment by adjusting the wind frequency, and then adjusts the wind gate for fine adjustment, thereby adjusting the operating frequency of the fan until the wind speed of the upper hull and the lower hull meets the set wind speed.

[0022] Among them, the control method of mainly adjusting the wind frequency and supplemented by adjusting the wind gate is adopted to effectively enhance the control capability, thereby ensuring the efficiency of the hull and improving the efficiency of electrode coating.

[0023] Reference Figure 2 Specifically, in the wind speed closed-loop regulation, when the wind speed of the upper hull and the wind speed of the lower hull do not meet the set value, the following steps are specifically included: S01. Monitor the real-time wind speed of the upper and lower hulls and determine the deviation from the set wind speed; S02. If the wind speed of the upper hull is greater than that of the lower hull, in the upper wind path adjustment control, the current state is that the upper wind gate is fully open. After recalculating the wind frequency of the fan, the upper wind gate opening is adjusted first. If the difference between the real-time wind speed of the upper hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the lower wind path wind gate opening is controlled to assist until the wind speed of the upper hull meets the set requirements; S03. If the wind speed of the lower hull is greater than that of the upper hull, in the lower wind path adjustment control, the current state is that the lower wind gate is fully open. After recalculating the wind frequency of the fan, the lower wind gate opening is adjusted first. If the difference between the real-time wind speed of the lower hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the upper wind path wind gate opening is controlled to assist until the wind speed of the lower hull meets the set requirements; S04. Re-judge the deviation between the wind speed of the upper hull and the lower hull and the set wind speed. If the requirements are met, the adjustment is completed; if the requirements are not met, repeat steps S01 to S03 until the wind speeds of the upper hull and the lower hull meet the set requirements.

[0024] Specifically, in the S02 step, the wind frequency control adjustment is performed based on the upwind path, and the specific steps include: judging the deviation between the real-time wind speed of the upper hull and the set wind speed. If the set requirements are met, the adjustment is completed; if the set requirements are not met, the opening of the upwind gate is adjusted, and the judgment of the deviation between the real-time wind speed of the upper hull and the set wind speed is continued until the set conditions are met and the adjustment is completed.

[0025] In the step S02, the downwind passage assists in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging the deviation between the real-time wind speed of the upper hull and the set wind speed, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, readjusting the downwind gate opening until the set conditions are met, and the adjustment is completed.

[0026] In the step S03, the wind frequency control is performed based on the downwind path, and the specific steps include: judging the deviation between the real-time wind speed of the lower hull and the set wind speed, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, adjust the opening of the upper wind gate, continue to judge the deviation between the real-time wind speed of the lower hull and the set wind speed and re-execute the fan wind frequency until the set conditions are met and the adjustment is completed.

[0027] In the step S03, the upwind path assists in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging the deviation between the real-time wind speed of the lower hull and the set wind speed, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, readjust the downwind gate opening until the set conditions are met, and the adjustment is completed.

[0028] Among them, the separate repeated adjustment of the upper hull and the lower hull in the existing technology is changed to synchronous linkage adjustment, and the wind gate control and the wind gate and wind frequency linkage control are utilized. The new control method and control logic are adopted to make the existing control method more three-dimensional, simplify the adjustment process and improve the adjustment accuracy.

[0029] The NMP closed-loop regulation is performed by monitoring the NMP concentration sensor to determine whether the set conditions are met, and the exhaust ratio and exhaust volume are adjusted in a closed-loop manner. After the adjustment is completed, the oven concentration is monitored and determined again until the monitored concentration meets the set value, completing the closed-loop regulation.

[0030] Among them, negative pressure regulation is included in the exhaust ratio regulation, and the NMP concentration or humidity is adjusted through the combined effect of the exhaust ratio and exhaust volume; the adjustment interlocking mode is changed and the interlocking system is added to improve the control accuracy while interlocking the key parameters of each system to avoid control conflicts caused by independent adjustment of each subsystem.

[0031] Reference Figure 3 Specifically, the NMP closed-loop regulation includes the following steps: S31. Monitor the NMP concentration sensor to determine whether the real-time concentration meets the set value deviation requirement, that is, the current oven concentration is within the expected maximum tolerance. If it meets the requirement, proceed to the next step; if it does not meet the requirement, repeat the closed-loop adjustment of the exhaust ratio and exhaust volume until the requirement is met; S32, determine whether the real-time concentration meets the set concentration value. If the real-time concentration is not greater than the set concentration, reduce the exhaust ratio and proceed to the next step. If the real-time concentration is not less than the set concentration, there is no need to repeatedly cycle through the previous step. Only the exhaust ratio needs to be fine-tuned. Directly increase the exhaust ratio and proceed to the next step, effectively improving the regulation efficiency. S33, determine whether the detected concentration meets the set concentration value deviation; if it does not meet the concentration requirement, repeat steps S31-S32 until the requirement is met, and if it meets the requirement, complete the closed-loop adjustment.

[0032] In addition, as a fool-proof process, a loop judgment will be performed to ensure that the "blind adjustment" in the current step will not destroy the overall balance. Otherwise, it is necessary to return to the adjustment step of S31 and complete the closed-loop submission again.

[0033] The exhaust ratio closed-loop regulation monitors the current exhaust ratio and determines whether it meets the set requirements, calculates the wind frequency of the exhaust fan, and adjusts the exhaust ratio by adjusting the oven negative pressure value until the exhaust ratio adjustment requirements are met.

[0034] Among them, double adjustment is added. When the set requirements are not met, the wind frequency is first roughly adjusted and then fine-tuned; when the set requirements are met, the one-way wind frequency adjustment is changed to the wind frequency and wind gate linkage adjustment; the control logic of the one-way control is changed, feedback adjustment is added, the control accuracy is improved, the adjustment difficulty is reduced, and the linkage adjustment gives the system a larger tolerance.

[0035] Reference Figure 4 Specifically, the closed-loop adjustment of the exhaust ratio includes the following steps: S11. Monitor the current exhaust ratio to determine whether it meets the set exhaust ratio requirement. If it meets the set value, the adjustment is completed. If it does not meet the set value, the set frequency is executed and the real-time negative pressure value is determined to meet the wide range of the set negative pressure value. S12. If the real-time negative pressure value does not meet the set requirement, the real-time negative pressure value is judged. If the real-time negative pressure value is greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set lower limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set lower limit of the fresh air gate opening, the fresh air gate opening is reduced. If the fresh air gate opening is greater than the set lower limit of the fresh air gate opening, the total fresh air frequency is reduced. If the real-time negative pressure value is not greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set upper limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set upper limit of the fresh air gate opening, the fresh air gate opening is increased. If the fresh air gate opening is greater than the set upper limit of the fresh air gate opening, the total fresh air frequency is increased. It is judged again whether the real-time negative pressure value is within the set range. If it meets the requirements, proceed to the next step. If it does not meet the requirements, repeat the above steps until the set requirements are met. S13. If the real-time negative pressure value meets the set requirements, the fan frequency is checked to see if it exceeds the upper and lower limits of the set fan frequency. If the fan frequency does not exceed the upper and lower limits of the set fan frequency, the real-time exhaust wind speed is judged to see if it meets the large range of calculated wind speed values. If it does not meet the requirements, the S12 step is repeated until the real-time exhaust wind speed meets the large range of calculated wind speed values. If it meets the requirements, the real-time exhaust wind speed is judged again to meet the calculated wind speed values. If it meets the requirements, the small fan frequency or the large fan frequency is fine-tuned until the current exhaust ratio meets the set exhaust ratio requirements. If it does not meet the requirements, the small fan frequency or the large fan frequency is roughly adjusted. Until the current exhaust ratio meets the set exhaust ratio requirement; if the fan frequency exceeds the upper and lower limits of the set fan frequency, determine whether the real-time fan frequency is less than the lower limit of the set fan frequency. If it meets the set requirements, turn off the exhaust fan, adjust the damper, and then determine the damper closing state. If it meets the requirements, the adjustment is completed. If it does not meet the requirements, determine whether the current exhaust ratio meets the set exhaust ratio requirement. If it meets the requirements, the adjustment is completed. If the fan frequency exceeds the upper and lower limits of the set fan frequency, determine that the real-time fan frequency is not less than the lower limit of the set fan frequency, and adjust the exhaust fan to the maximum frequency of 50HZ to complete the adjustment.

[0036] The exhaust volume closed-loop regulation monitors the current exhaust volume to determine whether it meets the set requirements, calculates the wind frequency, and controls the exhaust volume by adjusting the exhaust fan wind frequency until the exhaust volume adjustment requirements are met.

[0037] Reference Figure 5 Specifically, the closed-loop adjustment of the exhaust volume includes the following steps: S21, determining whether the current exhaust volume meets the set exhaust volume ratio deviation requirement; S22: If the set requirements are met, the adjustment is completed; if the set requirements are not met, the theoretical optimal wind frequency is implemented based on the current actual working conditions; S23, determining whether the current exhaust volume meets the set exhaust volume actual deviation; if not, recalculate the wind frequency and repeat S22 until it meets the requirement, then proceed to the next step; S24, determining whether the current exhaust volume meets the actual air volume. If it meets the requirement, adjust the air frequency down; if it does not meet the requirement, adjust the air frequency up, and then proceed to the next step; S25. Determine whether the current exhaust volume meets the set exhaust volume ratio deviation requirement. If it meets the requirement, the adjustment is completed; if it does not meet the requirement, repeat steps S23-S24 until the exhaust volume adjustment requirement is met.

[0038] Among them, a secondary judgment is added, and the wind frequency is adjusted again through fine-tuning to improve the adjustment accuracy and reduce the impact of errors on the entire control system.

[0039] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A closed-loop control method for oven drying process parameters, characterized in that: It includes wind speed closed-loop regulation and NMP closed-loop regulation, and the NMP closed-loop regulation includes exhaust ratio closed-loop regulation and exhaust volume closed-loop regulation; The wind speed closed-loop regulation monitors the current wind speed of the upper and lower hulls and determines whether it meets the set requirements. The wind frequency is first adjusted and then the wind gate is adjusted to adjust the operating frequency of the fan until the wind speed of the upper and lower hulls meets the set wind speed. The NMP closed-loop regulation is performed by monitoring the NMP concentration sensor to determine whether the set conditions are met, and the exhaust ratio and exhaust volume are adjusted in a closed-loop manner. After the adjustment is completed, the oven concentration is monitored and judged again until the monitored concentration meets the set value, and the closed-loop regulation is completed; The exhaust ratio closed-loop adjustment monitors the current exhaust ratio and determines whether it meets the set requirements. It calculates the exhaust fan's wind frequency and adjusts the fresh air volume based on the negative pressure value required by the oven, thereby affecting the exhaust ratio until the exhaust ratio adjustment requirements are met. The exhaust volume closed-loop regulation monitors the current exhaust volume to determine whether it meets the set requirements, calculates the wind frequency, and controls the exhaust volume by adjusting the exhaust fan wind frequency until the exhaust volume adjustment requirements are met.

2. The closed-loop control method for oven drying process parameters according to claim 1, characterized in that: In the wind speed closed-loop regulation, when the wind speed of the upper hull and the wind speed of the lower hull do not meet the set values, the following steps are specifically included: S01. Monitor the real-time wind speed of the upper and lower hulls and determine the deviation from the set wind speed; S02. If the wind speed of the upper hull is greater than that of the lower hull, in the upper wind path adjustment control, the current state is that the upper wind gate is fully open. After recalculating the wind frequency of the fan, the upper wind gate opening is adjusted first. If the difference between the real-time wind speed of the upper hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the lower wind path wind gate opening is controlled to assist until the wind speeds of the upper and lower hulls meet the set requirements; S03. If the wind speed of the lower hull is greater than that of the upper hull, in the upper wind path adjustment control, the current state is that the lower wind gate is fully open. After recalculating the wind frequency of the fan, the lower wind gate opening is adjusted first. If the difference between the real-time wind speed of the lower hull and the set wind speed is still not met when the minimum opening is set, the wind frequency is calculated again and executed. Then, the above steps are repeated and the lower wind path wind gate opening is controlled to assist until the wind speeds of the upper and lower hulls meet the set requirements; S04. Re-judge the deviation between the wind speed of the upper hull and the lower hull and the set wind speed. If the requirements are met, the adjustment is completed; if the requirements are not met, repeat steps S01 to S03 until the wind speeds of the upper hull and the lower hull meet the set requirements.

3. The closed-loop control method for oven drying process parameters according to claim 2, characterized in that: In the step S02, the downwind passage assists in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging whether the real-time wind speed of the upper hull meets the set wind speed deviation, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, the downwind gate opening is readjusted until the set conditions are met, and the adjustment is completed.

4. The closed-loop control method for oven drying process parameters according to claim 2, characterized in that: In the step S03, the downwind passage assists in adjusting the wind gate opening, and the specific steps include: adjusting the downwind gate opening, judging whether the real-time wind speed of the upper hull meets the set wind speed, and if it meets the set requirements, the adjustment is completed; if it does not meet the set requirements, the downwind gate opening is readjusted until the set conditions are met, and the adjustment is completed.

5. The closed-loop control method for oven drying process parameters according to claim 1, characterized in that: The closed-loop adjustment of the exhaust ratio specifically includes the following steps: S11. Monitor the current exhaust ratio to determine whether it meets the set exhaust ratio requirement. If it meets the set value, the adjustment is completed. If it does not meet the set value, the set frequency is executed and the real-time negative pressure value is determined to meet the wide range of the set negative pressure value. S12. If the real-time negative pressure value does not meet the set requirement, the real-time negative pressure value is judged. If the real-time negative pressure value is greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set lower limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set lower limit of the fresh air gate opening, the fresh air gate opening is reduced. If the fresh air gate opening is greater than the set lower limit of the fresh air gate opening, the total fresh air frequency is reduced. If the real-time negative pressure value is not greater than the set upper limit of the negative pressure value, the fresh air gate opening and the set upper limit of the fresh air gate opening are judged. If the fresh air gate opening is less than the set upper limit of the fresh air gate opening, the fresh air gate opening is increased. If the fresh air gate opening is greater than the set upper limit of the fresh air gate opening, the total fresh air frequency is increased. It is judged again whether the real-time negative pressure value is within the set range. If it meets the requirements, proceed to the next step. If it does not meet the requirements, repeat the above steps until the set requirements are met. S13. If the real-time negative pressure value meets the set requirements, the fan frequency is checked to see if it exceeds the upper and lower limits of the set fan frequency. If the fan frequency does not exceed the upper and lower limits of the set fan frequency, the real-time exhaust wind speed is judged to see if it meets the calculated wind speed large range value. If it does not meet the requirements, the S12 step is repeated until the real-time exhaust wind speed meets the calculated wind speed large range value. If it meets the requirements, the real-time exhaust wind speed is judged again to meet the calculated wind speed value. If it meets the requirements, the small fan frequency or the large fan frequency is fine-tuned until the current exhaust ratio meets the set exhaust ratio requirements. If it does not meet the requirements, the small fan frequency or the large fan frequency is roughly adjusted. frequency until the current exhaust ratio meets the set exhaust ratio requirement; if the fan frequency exceeds the upper and lower limits of the set fan frequency, determine whether the real-time fan frequency is less than the lower limit of the set fan frequency. If it meets the set requirements, turn off the exhaust fan, adjust the damper, and then determine the damper closing state. If it meets the requirements, the adjustment is completed. If it does not meet the requirements, determine whether the current exhaust ratio meets the set exhaust ratio requirement. If it meets the requirements, the adjustment is completed. If the fan frequency exceeds the upper and lower limits of the set fan frequency, determine that the real-time fan frequency is not less than the lower limit of the set fan frequency, then adjust the exhaust fan to the maximum frequency and the adjustment is completed.

6. The closed-loop control method for oven drying process parameters according to claim 5, characterized in that: The maximum power of the exhaust fan is 50HZ.

7. The closed-loop control method for oven drying process parameters according to claim 1, characterized in that: The closed-loop regulation of the exhaust volume specifically includes the following steps: S21, determining whether the current exhaust volume meets the set exhaust volume ratio deviation requirement; S22: If the set requirements are met, the adjustment is completed; if the set requirements are not met, the theoretical optimal wind frequency is implemented based on the current actual working conditions; S23, determining whether the current exhaust volume meets the set exhaust volume actual deviation; if not, recalculate the wind frequency and repeat S22 until it meets the requirement, then proceed to the next step; S24, determining whether the current exhaust volume meets the actual air volume. If it meets the requirement, adjust the air frequency down; if it does not meet the requirement, adjust the air frequency up, and then proceed to the next step; S25. Determine whether the current exhaust volume meets the set exhaust volume ratio deviation requirement. If it meets the requirement, the adjustment is completed; if it does not meet the requirement, repeat steps S23-S24 until the exhaust volume adjustment requirement is met.

8. The closed-loop control method for oven drying process parameters according to claim 1, characterized in that: The NMP closed-loop regulation specifically includes the following steps: S31. Monitor the NMP concentration sensor to determine whether the real-time concentration meets the set value deviation requirement. If it meets the requirement, proceed to the next step; if it does not meet the requirement, repeat the closed-loop adjustment of the exhaust ratio and exhaust volume until the requirement is met; S32, determining whether the real-time concentration meets the set concentration value. If the real-time concentration is not greater than the set concentration, the exhaust ratio is reduced and the next step is performed. If the real-time concentration is not less than the set concentration, the exhaust ratio is increased and the next step is performed. S33, determine whether the detected concentration meets the set concentration value deviation; if it does not meet the concentration requirement, repeat steps S31-S32 until the requirement is met, and if it meets the requirement, complete the closed-loop adjustment.

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