Control method for working condition conversion of process air conditioning in cigarette workshop

Abstract

The present invention discloses a method for controlling the operating mode conversion of process air conditioners in cigarette workshops. The main design concept of the present invention is to address the problems of existing temperature and humidity control strategies for process air conditioners in cigarette workshops, such as hot and cold offset after system overshoot, frequent valve actuation, and high energy consumption. By setting an operating mode conversion line during the temperature control process, and based on the specific temperature control strategies of different process air conditioners, and utilizing the relationship between the measured temperature and the operating mode conversion line, the decision mechanism for air conditioner operating mode switching and PID control mode is optimized. On the one hand, the present invention can solve the many problems caused by overshoot in the existing center value control process. On the other hand, it can maximize energy saving while meeting process requirements and improve the applicability of variable temperature and humidity control.

Description

Technical Field

[0001] The present invention relates to the field of cigarette manufacturing, and in particular to a method for controlling the conversion of process air-conditioning working conditions in a cigarette workshop. Background Art

[0002] With the advancement of science and technology and process requirements, tobacco processing technology has placed ever-more stringent requirements on temperature and humidity control within production workshops. Currently, maintaining a constant temperature and humidity environment during cigarette production and storage in cigarette factories relies primarily on automated, centralized control of large-scale process air conditioning systems, typically using a full air supply system to provide the appropriate temperature and humidity for cigarette processing and storage.

[0003] Taking the automatic temperature control strategy for a process air conditioner in a cigarette factory as an example, to ensure consistent cigarette quality, the temperature in controlled areas such as production and storage should be maintained within a relatively stable range based on process requirements. Currently, most temperature control strategies for process air conditioners in cigarette factories employ central value control. Multiple sensors collect temperature values ​​to represent the average temperature and humidity in the controlled area. Based on the control requirements, the air conditioning system determines the current operating mode and automatically adjusts to the set temperature target, controlling the corresponding actuators. The heating and cooling valves operate to raise or lower the temperature to the set temperature. Simultaneously, a series of control theory methods are used to stabilize temperature and humidity fluctuations within the allowable range required by the process. However, this strategy employs precise temperature control targeting the central value, which can easily lead to system overshoot and heat / cold offset, resulting in significant energy waste.

[0004] To elaborate, the current temperature control method in cigarette factories mostly relies on center-value control. For example, in a production area with a controlled temperature requirement of 24±2°C, during temperature regulation, the system targets this center value of 24°C, controlling the operation of various actuators to maintain the temperature near the setpoint. Because air conditioning systems exhibit significant hysteresis, the I value can easily accumulate during the control process, causing continued heating or cooling after the setpoint has been reached. Suppose, during temperature regulation, the current temperature falls below the setpoint, the heating valve opens, and the temperature rises. Due to system hysteresis and overshoot, the temperature may exceed the setpoint during regulation. The PID control value is then reversed, easily switching from heating to cooling, with the surface cooling valve opening for cooling. This phenomenon can cause both heating and cooling to cancel each other out, resulting in a double waste of cooling and heat. Furthermore, frequent switching between different operating modes results in frequent valve starts and stops, shortening equipment life.

[0005] To address the high energy consumption of temperature and humidity control systems, process air conditioning in some areas of cigarette factories currently utilizes variable temperature and humidity control. This involves setting a variable temperature and humidity range within the upper and lower limits required by the production process. Within this range, when the temperature deviates from this range, the corresponding valve is actuated under PID control to bring the temperature back within the range. However, in actual control, setting the range too large risks exceeding the temperature limit, while setting the range too small is similar to center value control and has no energy-saving effect. Furthermore, the complex environment of cigarette factory production areas, where temperature and humidity are affected by a variety of factors, including the operating status of production units, machine heat generation, and the external environment, inevitably affects the temperature control accuracy of the process air conditioning, making this solution less practical. Summary of the Invention

[0006] In view of the above, the present invention aims to provide a method for controlling the switching of process air-conditioning working conditions in a cigarette workshop to solve the above-mentioned technical problems.

[0007] The technical solution adopted in the present invention is as follows:

[0008] The present invention provides a method for controlling the working condition conversion of process air conditioning in a cigarette workshop, which includes:

[0009] According to the temperature and humidity process requirements of the production area, set the cooling condition conversion line and heating condition conversion line of the process air conditioner;

[0010] Determine the temperature control strategy currently adopted by the process air conditioner, wherein the temperature control strategy includes: central value control or variable temperature and humidity control;

[0011] Under the central value control, when the measured temperature deviates from the temperature setting value during the regulation process and does not reach the preset working condition conversion line, the process air conditioner is disabled from switching working conditions until the measured temperature reaches or deviates from the working condition conversion line, triggering the process air conditioner to execute working condition switching and perform temperature regulation;

[0012] Under variable temperature and humidity control, when the measured temperature is within the preset heating condition conversion line and cooling condition conversion line, the output value of the PID controller is limited until the measured temperature deviates upward or downward from the corresponding condition conversion line, triggering the process air conditioner to execute condition switching and perform temperature adjustment.

[0013] In at least one possible implementation, when determining whether the process air conditioning unit is currently applying a central value control strategy, the control method specifically includes:

[0014] According to the current measured temperature and the preset temperature and humidity process requirements, match the current working conditions of the process air conditioner and set the temperature set value;

[0015] If the current working condition matches the heating condition, the heating valve is opened to gradually increase the measured temperature. Before reaching the cooling condition conversion line, the trigger is disabled to convert to the cooling condition.

[0016] Until the measured temperature reaches the preset cooling mode conversion line, the switch to the cooling mode is triggered and the temperature is adjusted.

[0017] In at least one possible implementation, when determining whether the process air conditioning unit is currently applying a central value control strategy, the control method further includes:

[0018] If the current working condition matches the cooling condition, the surface cooling valve is opened to gradually reduce the measured temperature. Before reaching the heating condition conversion line, the trigger is disabled to convert to the heating condition.

[0019] Until the measured temperature reaches the preset heating mode conversion line, the switch to the heating mode is triggered and the temperature is adjusted.

[0020] In at least one possible implementation, when determining whether the process air conditioning unit is currently applying a central value control strategy, the control method includes:

[0021] After the measured temperature reaches and deviates from the temperature setting value, the valve opening corresponding to the current working condition is gradually reduced according to the calculated value of the PID controller, and the temperature change trend is judged after the valve stops moving;

[0022] If it is determined that the change trend of the measured temperature is approaching the temperature setting value, the valve is kept closed;

[0023] If it is determined that the variation trend of the measured temperature is an increasing deviation from the temperature setting value, the operating mode switching is forcibly triggered.

[0024] In at least one possible implementation, determining the temperature change trend includes:

[0025] Set a time window of preset length, which contains a set of temperature values

[0026] Calculate the average of the temperature values ​​contained in the time window before and after sliding by a preset distance:

[0027] Determine the temperature change trend based on the change difference of the average temperature.

[0028] In at least one possible implementation, when determining whether the process air conditioning unit is currently applying a variable temperature and humidity control strategy, the control method specifically includes:

[0029] Set the cooling condition conversion line and heating condition conversion line based on historical data;

[0030] When the current measured temperature is between the cooling condition conversion line and the heating condition conversion line, the output value of the PID controller is limited so that the temperature control target changes dynamically with the measured temperature;

[0031] When the measured temperature rises above the cooling condition conversion line, or drops below the heating condition conversion line, it triggers the conversion to the corresponding cooling condition or heating condition, and the temperature is adjusted by calculating through the PID controller.

[0032] In at least one possible implementation, when determining whether the process air conditioning unit is currently applying a variable temperature and humidity control strategy, the control method further includes:

[0033] During the process of the measured temperature increasing or decreasing, the deviation of the measured temperature from the corresponding working condition conversion line within the preset time period is periodically calculated;

[0034] Based on the amplitude, the corresponding operating condition conversion line is adjusted.

[0035] In at least one possible implementation manner, adjusting the corresponding operating condition conversion line includes:

[0036] The preset safety factor is combined with the amplitude, and the corresponding operating condition conversion line is dynamically reset based on the overshoot amount as the adjustment basis.

[0037] The main design concept of this invention is to address the problems of existing temperature and humidity control strategies for process air conditioners in cigarette workshops, such as hot and cold offsets after system overshoot, frequent valve actuation, and high energy consumption. By setting a working condition transition line during the temperature control process and utilizing the relationship between measured temperature and the working condition transition line according to the specific temperature control strategies of different process air conditioners, the decision-making mechanism for air conditioner working condition switching and PID control mode is optimized. On the one hand, this invention can solve the many problems caused by overshoot in the existing center value control process. On the other hand, it can maximize energy savings while meeting process requirements and improve the applicability of variable temperature and humidity control. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described below with reference to the accompanying drawings, in which:

[0039] Figure 1 This is a flow chart of a method for controlling the conversion of process air conditioning working conditions in a cigarette workshop provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0041] The present invention proposes an embodiment of a method for controlling the working condition conversion of a process air conditioning in a cigarette workshop. Taking the temperature control loop as an example, specifically, Figure 1 shown, including:

[0042] Step S1: setting the cooling mode conversion line and the heating mode conversion line of the process air conditioner according to the temperature and humidity process requirements of the production area;

[0043] Step S2: determining the temperature control strategy currently adopted by the process air conditioner, wherein the temperature control strategy includes: central value control or variable temperature and humidity control;

[0044] Step S30: Under the central value control, when the measured temperature deviates from the temperature setting value during the regulation process and does not reach the preset operating condition conversion line, the process air conditioner is disabled from switching the operating condition until the measured temperature reaches or deviates from the operating condition conversion line, at which time the process air conditioner is triggered to perform operating condition switching and temperature regulation;

[0045] Step S40: Under variable temperature and humidity control, when the measured temperature is within the preset heating condition conversion line and cooling condition conversion line, the output value of the PID controller is limited until the measured temperature deviates upward or downward from the corresponding condition conversion line, triggering the process air conditioner to execute condition switching and perform temperature adjustment.

[0046] For the two different air conditioning temperature control strategies mentioned above, specific implementation examples are provided below for reference.

[0047] 1. When judging that the process air conditioning unit is currently applying the central value control strategy, set the temperature set value T S , Refrigeration condition conversion line T C1 , Heating condition conversion line T H1 , and can refer to the following specific implementation steps:

[0048] (1) Match the current working conditions of the process air conditioner according to the current measured temperature and the preset temperature and humidity process requirements;

[0049] (21) If the current working condition matches the heating condition, the heating valve is opened to gradually increase the current measured temperature to the set temperature T S Above, in this stage, the trigger is disabled and converted to cooling mode;

[0050] (22) Until the current measured temperature reaches the cooling condition conversion line TC1 , triggering the switch to cooling mode and temperature adjustment.

[0051] (31) If the current working condition matches the cooling condition, the surface cooling valve is opened to gradually reduce the current measured temperature to the set temperature T S In the following, the disabled trigger is converted to heating mode in this stage;

[0052] (32) Until the current measured temperature reaches the heating condition conversion line T H1 , triggering the switch to heating mode and temperature adjustment.

[0053] Furthermore, under this temperature control strategy, it also includes:

[0054] After the current measured temperature reaches and deviates from the temperature set value, the valve corresponding to the current working condition (depending on the working condition type) gradually reduces the opening according to the calculated value of the PID controller, and the temperature change trend is judged after the valve stops moving;

[0055] If it is determined that the current measured temperature is trending toward the temperature setting value, the valve is kept closed;

[0056] If it is determined that the variation trend of the currently measured temperature is an increasing deviation from the temperature setting value, the operating mode switching is forcibly triggered.

[0057] Specifically, the temperature change trend determination includes:

[0058] Select a time window of fixed length i, which contains a set of temperature values:

[0059] T={T1,T2,T3,...,T i}

[0060] Among them, T1, ..., T i is the temperature at the corresponding moment.

[0061] Calculate the first temperature average within the current time window:

[0062]

[0063] Where k∈{1, 2, ..., i}.

[0064] Slide the time window according to a preset sliding distance a, and calculate the second temperature average value in the sliding time window:

[0065]

[0066] Similarly, the n first temperature averages are compared with the second temperature average to determine the temperature change trend. This incorporates the time factor. When the measured temperature is gradually approaching the setpoint, it indicates that the external environment can reduce the temperature deviation from the setpoint, thus eliminating the need to switch operating modes and allowing the corresponding valves to remain closed. Conversely, when the deviation between the measured temperature and the setpoint continues to increase, it indicates a significant external environmental impact. To promptly overcome this, the air conditioning operating mode can be forcibly switched, triggering the corresponding valve to operate and triggering a temperature correction.

[0067] Furthermore, it can be explained that if the precondition and the transition condition are the same, the trigger is not triggered. For example, if the current measured temperature is high (above the cooling condition transition line), the process air conditioner must be in cooling condition. When the temperature is controlled to drop below the cooling condition transition line, the air conditioner is not affected and continues to maintain the current cooling condition. This is not until the current measured temperature reaches the setpoint, at which point the surface cooling valve is triggered to close, terminating the current cooling condition. The humidity control loop is similar.

[0068] 2. When judging the variable temperature and humidity control strategy currently used in the process air conditioning unit, set the cooling condition conversion line T according to historical data. C2 , Heating condition conversion line T H2 , and can refer to the following specific implementation steps:

[0069] (1) When the current measured temperature is between the two working condition conversion lines, the temperature control target changes dynamically with the measured temperature, limiting the output value of the PID controller (that is, the valve under the corresponding working condition does not operate at this time);

[0070] (2) When the measured temperature rises to the cooling condition conversion line T C2 Above, or lower to the heating condition conversion line T H2 When the temperature drops below 0.05, the system triggers the switch to the corresponding cooling or heating condition, and the temperature is adjusted by calculating through the PID controller, and the corresponding valve is controlled to adjust the temperature.

[0071] Furthermore, under this temperature control strategy, it also includes:

[0072] Periodically calculate the deviation of the measured temperature from the operating condition conversion line within a preset time period;

[0073] Based on the magnitude, the operating condition transfer line is adjusted.

[0074] Specifically, when the process air conditioner is in the variable temperature and humidity control strategy, calculate the extent to which the measured temperature deviates upward from the working condition cooling condition conversion line over a period of time:

[0075] e s (t) = T j (t)-T C2

[0076] Or, the extent to which the measured temperature deviates downward from the heating condition conversion line:

[0077] e S (t) = T H2 -T j (t)

[0078] Based on the calculation results of the above amplitude, the temperature range can be expanded or reduced on the basis of the originally set working condition conversion line. In actual operation, the preset safety factor k can be combined with the amplitude (in k·e S (t) serves as the conversion line adjustment accuracy standard. Based on the overshoot, the operating condition conversion line is dynamically reset to ensure that the temperature does not exceed the production process requirements after the dynamic change of the operating condition conversion line. The humidity control loop is similar.

[0079] In summary, the main design concept of this invention is to address the problems of existing temperature and humidity control strategies for process air conditioners in cigarette workshops, such as hot and cold offsets after system overshoot, frequent valve actuation, and high energy consumption. By setting a working condition conversion line during the temperature control process, and based on the specific temperature control strategies of different process air conditioners, and utilizing the relationship between measured temperature and working condition conversion line, the decision-making mechanism for air conditioner working condition switching and PID control mode is optimized. On the one hand, this invention can solve the many problems caused by overshoot in the existing center value control process. On the other hand, it can maximize energy savings while meeting process requirements and improve the applicability of variable temperature and humidity control.

[0080] In the embodiment of the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent the existence of A alone, the existence of A and B at the same time, and the existence of B alone. A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b and c can be represented by: a, b, c, a and b, a and c, b and c, or a, b and c, where a, b, c can be single or multiple.

[0081] The above describes in detail the structure, features and effects of the present invention based on the embodiments shown in the drawings, but the above is only a preferred embodiment of the present invention. It should be noted that the technical features involved in the above embodiments and their preferred modes can be reasonably combined and matched into a variety of equivalent schemes by those skilled in the art without departing from or changing the design ideas and technical effects of the present invention; therefore, the scope of implementation of the present invention is not limited to what is shown in the drawings. Any changes made in accordance with the concept of the present invention, or modifications to equivalent embodiments with equivalent changes, which still do not exceed the spirit covered by the description and drawings, should be within the scope of protection of the present invention.

Claims

1. A cigarette workshop process air conditioning working condition conversion control method, characterized in that: include: According to the temperature and humidity process requirements of the production area, set the cooling condition conversion line and heating condition conversion line of the process air conditioner; Determine the temperature control strategy currently adopted by the process air conditioner, wherein the temperature control strategy includes: central value control or variable temperature and humidity control; Under the central value control, when the measured temperature deviates from the temperature setting value during the regulation process and does not reach the preset working condition conversion line, the process air conditioner is disabled from switching the working condition until the measured temperature reaches or deviates from the working condition conversion line, triggering the process air conditioner to execute working condition switching and perform temperature adjustment; and, when it is determined that the process air conditioner unit is currently applying the central value control strategy, after the measured temperature reaches and deviates from the temperature setting value, the opening of the valve corresponding to the current working condition is gradually reduced according to the calculated value of the PID controller, and the temperature change trend is judged after the valve stops moving; if it is determined that the change trend of the measured temperature is an increasing deviation from the temperature setting value, the working condition conversion line is ignored and the working condition switching is forcibly triggered; Under variable temperature and humidity control, when the measured temperature is within the preset heating condition conversion line and cooling condition conversion line, the output value of the PID controller is limited until the measured temperature deviates upward or downward from the corresponding condition conversion line, triggering the process air conditioner to execute condition switching and perform temperature adjustment.

2. The cigarette workshop process air conditioning working condition conversion control method according to claim 1 is characterized in that: When determining that the process air conditioning unit is currently applying the central value control strategy, the control method specifically includes: According to the current measured temperature and the preset temperature and humidity process requirements, match the current working conditions of the process air conditioner and set the temperature set value; If the current working condition matches the heating condition, the heating valve is opened to gradually increase the measured temperature. Before reaching the cooling condition conversion line, the trigger is disabled to convert to the cooling condition. Until the measured temperature reaches the preset cooling mode conversion line, the switch to the cooling mode is triggered and the temperature is adjusted.

3. The cigarette workshop process air conditioning operating mode conversion control method according to claim 2, characterized in that: When determining that the process air conditioning unit is currently applying the central value control strategy, the control method further includes: If the current working condition matches the cooling condition, the surface cooling valve is opened to gradually reduce the measured temperature. Before reaching the heating condition conversion line, the trigger is disabled to convert to the heating condition. Until the measured temperature reaches the preset heating mode conversion line, the switch to the heating mode is triggered and the temperature is adjusted.

4. The cigarette workshop process air conditioning operating mode conversion control method according to claim 1, characterized in that: The temperature change trend judgment includes: Set a time window of a preset length, which contains a set of temperature values. Calculate the average value of the temperature values ​​contained in the time window before and after sliding by a preset distance: Determine the temperature change trend based on the change difference of the average temperature.

5. The cigarette workshop process air conditioning working condition conversion control method according to claim 1 is characterized in that: When determining that the process air conditioning unit is currently applying the variable temperature and humidity control strategy, the control method specifically includes: Set the cooling condition conversion line and heating condition conversion line based on historical data; When the current measured temperature is between the cooling condition conversion line and the heating condition conversion line, the output value of the PID controller is limited, and the temperature control target changes dynamically with the measured temperature; When the measured temperature rises to the cooling condition conversion line T C2 Above, or lower to the heating condition conversion line T H2 When the temperature is below 0.05, it triggers the conversion to the corresponding cooling or heating condition, and the temperature is adjusted by the PID controller.

6. The cigarette workshop process air conditioning operating mode conversion control method according to claim 5, characterized in that: When determining that the process air conditioning unit is currently applying the variable temperature and humidity control strategy, the control method further includes: During the process of the measured temperature increasing or decreasing, the deviation of the measured temperature from the corresponding working condition conversion line within the preset time period is periodically calculated; Based on the amplitude, the corresponding operating condition conversion line is adjusted.

7. The cigarette workshop process air conditioning operating mode conversion control method according to claim 6, characterized in that: The adjustment of the corresponding operating condition conversion line includes: The preset safety factor is combined with the amplitude, and the corresponding operating condition conversion line is dynamically reset based on the overshoot amount as the adjustment basis.

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