A multi-feedback oven heating system and control method

Abstract

The application discloses a multi-feedback oven heating system and a control method, and relates to the technical field of ovens.The method comprises the following steps: S1: an operator inputs heating parameters, a system reads and executes the heating parameters, the system judges whether a heating button is started or not, and when the heating button is started, S2 is executed; S2: a main temperature control setting value is set to be higher than a process temperature of a heated object, when the temperature of the heated object reaches a heating stop point monitoring temperature, the heating system is turned off, at this time, the air temperature in the oven decreases, the temperature of the heated object continues to rise, and when the temperature of the heated object reaches the process temperature of the heated object, S3 is executed; S3: the main temperature control setting value is corrected according to the actual temperature of the heated object on the basis of a holding heating setting temperature, and the holding time is timed. The control system is used for assisting in determining a stop heating correction amount and a stop heating monitoring temperature point, and the test time and process required for simply manually confirming the two parameters are shortened.

Description

Technical Field

[0001] This invention relates to the field of oven technology, and in particular to a multi-feedback oven heating system and control method. Background Technology

[0002] Traditional ovens have a wide range of applications. For example, in the production of composite material molding and antenna body molding foam, ovens are used as a heat source to heat metal molds. Traditional oven heating primarily utilizes hot air to indirectly heat items within the oven. The general heating process involves current passing through heating elements (resistance wires, plate heaters, etc.) to raise their temperature, heating the air flowing around them. This air then reaches the heating zone through the air outlet, heating the items being heated. The system includes: the oven body, heating elements, a blower, a main control temperature instrument, an air outlet temperature probe, an over-temperature alarm instrument, and an over-temperature detection probe. The air outlet temperature probe transmits the measured actual temperature value of the hot air to the main control temperature instrument. The main control temperature instrument compares this with the set temperature and sends a control signal. Upon receiving the control signal, the heating element switches on and off and adjusts the heating intensity. The over-temperature alarm probe is typically located in the drying area of ​​the oven, transmitting its measured value to the over-temperature alarm instrument. If the temperature exceeds the safe range, the over-temperature alarm instrument sounds an alarm through a loudspeaker and shuts down the heating system. Traditional ovens, when used in actual production processes such as composite material molding and antenna body molding foaming, suffer from problems including slow heating of large, heavy objects like molds and the inability to control the temperature of the heated object manually and indirectly. Specifically:

[0003] 1. Inability to automatically regulate the actual temperature of the heated object: Traditional ovens only read the actual temperature at the air outlet from the temperature probe, compare it with the set temperature, and then send an action command to the heating element, thus affecting the actual temperature at the air outlet. In other words, existing ovens can only directly control the air outlet temperature and cannot control the actual temperature of the heated object. Most traditional ovens do not have dedicated temperature probes and instruments to measure the temperature of the heated object (material). A few with such devices only provide temperature feedback to the operator, who then manually adjusts the main temperature instrument setpoint, affecting the air temperature inside the oven and consequently the actual temperature of the heated object. Therefore, automatic control of the actual heated temperature around the required process temperature is impossible.

[0004] 2. Slow heating rate, affecting product production efficiency: For large objects (such as heavy steel molds), the heating rate in hot air is slow and much lower than the temperature rise rate of the hot air itself. For example, in an oven, it takes about 30 minutes for the hot air at the vent to reach the set temperature of 120°C from room temperature (20°C), while it takes about 80 minutes for the mold inside to reach 100°C. The subsequent rise from 100°C to 118°C takes 60 minutes or longer because the temperature difference between the hot air and the mold decreases in the later stages, causing the mold to heat up even more slowly.

[0005] 3. The holding time of the heated object cannot be automatically confirmed: Traditional ovens require manual identification by monitoring the temperature value to determine the holding time of the heated object. The oven holding time starts when the hot air outlet temperature reaches the set value, which is different from the actual temperature of the heated object entering the holding state.

[0006] 4. Inability to comprehensively reflect the oven's operating status: Ordinary ovens typically only have one thermal control gas sensor, which works in conjunction with the main temperature controller to control the internal hot air temperature, plus a separate over-temperature sensor and controller. Monitoring of the actual temperature of the heated object and the temperature of the surrounding hot air is incomplete. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a multi-feedback oven heating system and control method.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A first aspect of the present invention provides a method for controlling the heating of a multi-feedback oven, comprising the following steps:

[0010] S1: Initialization phase. The operator inputs heating parameters, the system reads and executes the heating parameters, and the system determines whether the heating button is activated. When the heating button is activated, the S2 heating phase is executed.

[0011] S2: Heating stage. Set the main temperature control setting value to be higher than the process temperature of the heated object. When the temperature of the heated object reaches the heating stop point monitoring temperature, turn off the heating system. At this time, the air temperature in the oven will drop and the temperature of the heated object will continue to rise. When the temperature of the heated object reaches the process temperature of the heated object, execute the S3 heat preservation stage.

[0012] During the S3 heat preservation stage, the main temperature control setpoint is adjusted based on the actual temperature of the heated object, using integral correction, to determine the heat preservation time. When the temperature of the heated object reaches the heating stop point monitoring temperature (below the lower limit of the process temperature requirement), the heating system is shut down in advance. The heating stop point monitoring temperature = the process temperature of the heated object - the heating stop correction amount, to prevent temperature overshoot and exceeding the upper limit of the process temperature.

[0013] Preferably, the S1 initialization phase further includes the following steps:

[0014] S11: Operator inputs heating parameters: process temperature of heated object Tg, process temperature tolerance of heated object ±A, holding time t 保 , Heating increase amount Tsx, Heating stop correction amount Txx, Heating heat preservation correction amount Tbx, Heating temperature drop confirmation time M, Maximum allowable heating temperature Tmax;

[0015] S12: The system reads and executes the heating parameters: rapid heating set temperature: Tzs=Tg+Tsx, heat preservation heating set temperature: Tbs=Tg+Tbx, heating stop point monitoring temperature: Tjt=Tg-Txx;

[0016] S13: After the heating button is activated, the main temperature control setting value Tzx is set to the rapid heating setting temperature Tzs.

[0017] Preferably, the S2 heating stage further includes the following steps:

[0018] When the heating system is turned off, if the temperature of the heated object reaches a peak and then continues to drop, and the drop time is greater than or equal to the temperature drop confirmation time M, and the temperature of the heated object cannot reach the process temperature Tg, active heating will be initiated in advance. The main temperature control setpoint will be set to the heat preservation temperature. The difference between the process temperature and the actual temperature of the heated object will be calculated and integrated over time. The main temperature control setpoint will be corrected using this processed value until the temperature of the heated object reaches the process temperature Tg. At this point, the heat preservation stage S3 begins, and the heat preservation time is recorded.

[0019] Preferably, the S2 heating stage further includes the following steps:

[0020] Before monitoring the temperature to find the heating stop point, the system is in a state before heating begins, with the oven temperature close to room temperature. Input the process temperature Tg of the heated object, the process temperature tolerance ±A, and the temperature rise Tsx. After initiating the self-tuning process to find the heating stop point and monitor the temperature, the system automatically calculates the rapid heating setpoint Tzs and starts heating. When the actual temperature Tw of the heated object ≥ Tg, record this moment as t0 and shut down the heating system to allow the hot air to cool. At this time, the actual temperature Tw of the heated object continues to rise, while the air temperature Tk near the heated object in the oven begins to decrease. Periodically check the actual temperature Tw of the heated object and the air temperature Tk near the heated object in the oven. When Tw reaches the highest temperature Twg of the heated object, record this moment as t1. When Tk ≤ Tg, record this moment as t2. Calculate the heating stop correction Txx and the final heating stop point monitoring temperature Tjt using the following formula:

[0021] Heating stop correction amount: Txx=(Twg-Tg)*((t2-t0) / (t1-t0))

[0022] Monitoring temperature at the heating stop point: Tjt = Tg - Txx

[0023] Where: Twg is the highest temperature of the heated object during self-tuning, Tg is the process temperature of the heated object, t0 is the moment when the actual temperature of the heated object Tw≥Tg, t1 is the moment when the actual temperature of the heated object reaches its highest point, and t2 is the moment when the air temperature near the heated object in the oven Tk≤Tg.

[0024] Preferably, the S3 heat preservation stage further includes the following steps:

[0025] S31: When the system first detects that the actual temperature TW of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, the system reads the current time as the start time t of the heat preservation process. 保启 As the insulation process continues, the system time t 系统 The actual heat preservation time t is constantly increasing. 保实 =t 系统 -t 保启 When the actual heat preservation time t 保实 ≥t 保温 When the total insulation time required by the process is reached, the S3 insulation stage ends.

[0026] Preferably, the S3 heat preservation stage further includes the following steps:

[0027] S32: When the system first detects that the actual temperature TW of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, it starts calculating the temperature deviation ΔT=Tg-Tw, integrating it over time t, correcting the integral with a coefficient, adding it to the heat preservation and heating set temperature Tbs, and resetting the main temperature control set value to the summed value. Specifically as follows:

[0028] Integral correction of main temperature control setpoint: The integration period in the above formula is from the start time t0 of heat preservation to the current time ti. In actual calculation, the temperature is sampled periodically and the incremental sum is accumulated to calculate the integral value. The step-by-step calculation of the integral correction of the main temperature control heat preservation setpoint is as follows:

[0029] M0=0, the initial temperature difference integral during the heat preservation stage is set to 0;

[0030] Tbs=Tg+Tbx, the heat preservation and heating set temperature is equal to the sum of the process temperature of the heated object and the heat preservation and heating correction amount;

[0031] ΔT i =Tg-Tw, current t i The difference between the process temperature of the object being heated and the actual temperature of the object being heated at any given time;

[0032] M i =M i-1 +tz*ΔT i / 1000, the current temperature deviation integral is the sum of the previous integral and the current integral increment;

[0033] Tzx i =Tbs+(1 / K d M i The current main temperature control insulation execution value is equal to the sum of the current integral value divided by the integral coefficient and the insulation setting value;

[0034] Where: Tzx is the main temperature control and heat preservation execution value, Tw is the current actual temperature of the heated object, Tbs is the set temperature for the heat preservation stage, and K... d M0 is the temperature integral correction factor, in seconds; Tbx is the initial temperature difference integral during the insulation stage; and ΔT is the temperature correction amount during the insulation stage. i Let Tg be the difference between the process temperature in the i-th sampling period and the actual temperature of the object being heated, and M be the process temperature of the object being heated. i-1 The integral of temperature for the (i-1)th sampling period, tz, is the sampling period, Tzx i For the i-th sampling period, the main temperature control and insulation execution value is calculated after each temperature sampling, Tzx is used. i And update the main temperature control setting to Tzx i This continues until the S3 heat preservation stage ends. When the corrected current main temperature control setting value Tzxi is greater than or equal to the maximum allowable heating temperature Tmax, the main temperature control setting value Tzxi is set to Tmax to prevent the hot air temperature from becoming too high.

[0035] A second aspect of the present invention provides a multi-feedback oven heating system for performing any one of the methods described in claims 1-6, comprising a central control unit, a heated object temperature measurement module, a main temperature control module, an air outlet temperature measurement module, and a heating execution system. The output end of the heated object temperature measurement module is connected to the central control unit, which sends the actual temperature value of the heated object to the central control unit for processing. The output end and receiving end of the central control unit are connected to the main temperature control module. The receiving end of the main temperature control module is connected to the air outlet temperature measurement module. The output end of the main temperature control module is connected to the heating execution system, which sends the air outlet temperature value to the central control unit for processing and controls the output power of the heating execution system according to the signal transmitted by the central control unit.

[0036] Preferably, the receiving end of the heated object temperature measurement module is connected to the heated object temperature sensor, and the receiving end of the air outlet temperature measurement module is connected to the air outlet main temperature control sensor.

[0037] Preferably, it also includes an internal hot air temperature measurement module, wherein the receiving end of the internal hot air temperature measurement module is connected to an internal hot air temperature sensor.

[0038] Preferably, it also includes an over-temperature detection temperature control instrument, wherein the receiving end of the over-temperature detection temperature control instrument is connected to an over-temperature monitoring temperature sensor, and the output end is connected to a heating execution system. When the temperature reaches the set value, the heating execution system is turned off.

[0039] The beneficial effects of this invention are:

[0040] 1) It can achieve direct control of the temperature of the heated object. By equipping the heated object with a temperature sensor, the measured temperature of the heated object is transmitted to the temperature control system. Then, the main control set temperature and the heater are adjusted according to the situation to achieve indirect control of the temperature of the heated object.

[0041] 2) Shorten the heating time. When the object heats up, it lags behind the heating rate of the air in the oven. By increasing the temperature of the hot air in the oven environment, the heating rate of the heated object is increased, and it can quickly reach the heat preservation state, thus saving heating time.

[0042] 3) When using rapid heating, the control system assists in determining the correction amount for stopping heating during the rapid heating rise stage and the monitoring temperature point for stopping heating, thus shortening the test time and process required for manual confirmation of these two parameters.

[0043] 4) Automatically determine the heat preservation stage, time the heat preservation, and control the heat preservation: If the heated object is detected to have reached the lower limit of the process temperature during the heating stage, it is confirmed that the heated object has entered the heat preservation stage. The system enters the heat preservation program and calculates the deviation between the actual heated temperature and the process temperature (time integration or proportional processing) during the heat preservation. The processing result is used to correct the heat preservation setpoint of the main temperature controller, so as to realize the control of the actual heated temperature fluctuating around the process temperature.

[0044] 5) More comprehensive reflection of the actual working condition of the oven than ordinary ovens: The oven heating system of this invention, in addition to an independent over-temperature sensor and controller, is equipped with three types of temperature sensors. The first type is a sensor that can directly measure the temperature of the object being heated; the second type is a sensor that can measure the temperature of the air surrounding the heated object; and the third type is a main temperature control sensor at the air outlet. It can monitor the actual temperature of the heated object, the temperature of the hot air surrounding the heated object, and the temperature at the air outlet in real time. In contrast, ordinary ovens only have one sensor (located in the oven working chamber or at the air outlet) besides the over-temperature sensor, which directly measures the temperature of the hot air. Attached Figure Description

[0045] Figure 1 This is a block diagram of the multi-feedback oven heating system of the present invention;

[0046] Figure 2 This is a flowchart of the oven heating control method of the present invention;

[0047] Figure 3 This is a flowchart of the preheating sub-process of the heating stage in the control method of the present invention;

[0048] Figure 4 This is a flowchart of the control method for the heat preservation stage of the present invention;

[0049] Figure 5 Automatically locates the process temperature-time curve at the temperature point where heating stops and monitoring is activated;

[0050] Figure 6 A flowchart for finding the monitoring temperature point to stop heating. Detailed Implementation

[0051] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] See Figures 1-6 The first aspect of this invention provides: a multi-feedback oven heating control method, comprising the following steps:

[0053] S1: Initialization phase. The operator inputs heating parameters, the system reads and executes the heating parameters, and the system determines whether the heating button is activated. When the heating button is activated, the S2 heating phase is executed.

[0054] S2: Heating stage. Set the main temperature control setting value to be higher than the process temperature of the heated object. When the temperature of the heated object reaches the heating stop point monitoring temperature, turn off the heating system. At this time, the air temperature in the oven will drop and the temperature of the heated object will continue to rise. When the temperature of the heated object reaches the process temperature of the heated object, execute the S3 heat preservation stage.

[0055] During the S3 heat preservation stage, the main temperature control setting is adjusted based on the actual temperature of the heated object and the heat preservation time is recorded.

[0056] When the temperature of the heated object reaches the monitored temperature (below the lower limit of the process temperature requirement), the heating system is shut down prematurely. The monitored temperature is calculated as: monitored temperature = process temperature - heating stop correction amount. This prevents temperature overshoot and exceeding the upper limit of the process temperature. During the initial heating phase, the execution temperature of the main temperature controller is set significantly higher than the process temperature of the heated object. This increases the temperature difference between the oven air and the heated object, thereby increasing the heating rate. When the temperature of the heated object reaches the monitored temperature (below the lower limit of the process temperature requirement), the heating system is shut down prematurely. At this point, the air temperature inside the oven will decrease, and the temperature of the heated object will continue to rise. When the temperature of the heated object reaches the lower limit of the process temperature requirement, the set temperature of the main temperature controller is set to be equal to or slightly higher than the process temperature, allowing the oven system to enter a heat preservation state.

[0057] In some embodiments, the S1 initialization phase further includes the following steps:

[0058] S11: Operator inputs heating parameters: process temperature of heated object Tg, process temperature tolerance of heated object ±A, holding time t 保 , Heating increase amount Tsx, Heating stop correction amount Txx, Heating heat preservation correction amount Tbx, Heating temperature drop confirmation time M, Maximum allowable heating temperature Tmax;

[0059] S12: The system reads and executes the heating parameters: rapid heating set temperature: Tzs=Tg+Tsx, heat preservation heating set temperature: Tbs=Tg+Tbx, heating stop point monitoring temperature: Tjt=Tg-Txx;

[0060] S13: After the heating button is activated, the main temperature control setting value Tzx is set to the rapid heating setting temperature Tzs.

[0061] Before the oven rapidly heats up, initialize the system and input various parameters required for heating (process temperature Tg, temperature rise Tsx, heating correction Tbx, heating stop correction Txx, temperature drop confirmation time M for heated object, process temperature tolerance ±A). The system calculates the heating setpoint temperature Tzs = Tg + Tsx, the heating setpoint temperature Tbs = Tg + Tbx, and the heating stop monitoring temperature Tjt = Tg - Txx. After confirming heating start, set the main temperature control setpoint Tzx to Tzs (heating setpoint temperature), start heating, and wait for the next sampling cycle. The temperature of the heated object will continue to rise during this period. Each sampling cycle reads the actual temperature Tw of the heated object. If the condition Tw ≥ Tjk (heating stop monitoring temperature) is not met, continue sampling in the next cycle, maintaining the cycle until the condition Tw ≥ Tjk is met, exit the loop, and assign the current actual temperature Tw value of the heated object to the highest temperature T of the heated object. 最高 And record the time t when the highest temperature occurs. 最高 Update to the current time, reset the main temperature control setpoint to zero, begin cooling the oven with hot air, wait for the next sampling cycle, and continue reading the actual temperature Tw of the heated object. If Tw ≥ T... 最高 (Highest temperature of the object being heated), then the current actual temperature Tw of the object being heated is assigned to the highest temperature T of the object being heated. 最高 And the time t when the highest temperature point occurs. 最高 Update to the current time, determine if the actual temperature of the heated object Tw ≥ Tg-A (minimum process requirement temperature), if so, end the heating process and enter the holding stage; if not, continue the sampling cycle, monitoring the change in the heated object's Tw during the cycle. If Tw ≥ Tg-A is detected during the cycle... 最高 Not satisfied and current time t 当 -t 最高 ≥M seconds (t) 最高(M is the moment when the highest actual temperature of the heated object occurs, and M is the time when the temperature of the heated object is confirmed to have dropped). This indicates that the temperature of the heated object is continuously dropping, and at this moment, the preheating subprocess is started (see Appendix). Figure 3 (As shown) to ensure that the actual temperature of the heated object can rise again until the actual temperature of the heated object Tw≥Tg-A (the minimum required temperature of the process), then the heating process will be stopped and the heat preservation stage will be entered.

[0062] In some embodiments, the S2 heating stage further includes the following steps:

[0063] When the heating system is turned off, if the temperature of the heated object reaches a peak and then continues to drop, and the drop time is greater than or equal to the temperature drop confirmation time M, and the temperature of the heated object cannot reach the process temperature Tg, active heating will be initiated in advance. The main temperature control setpoint will be set to the heat preservation temperature. The difference between the process temperature and the actual temperature of the heated object will be calculated and integrated over time. The main temperature control setpoint will be corrected using this processed value until the temperature of the heated object reaches the process temperature Tg. At this point, the heat preservation stage S3 begins, and the heat preservation time is recorded.

[0064] When the temperature of the heated object reaches the monitored temperature (below the lower limit of the process temperature requirement), the heating system is shut down in advance. If the temperature of the heated object continues to rise and reaches the lower limit of the process temperature requirement, the main temperature controller is set to the hold-temperature setting, putting the oven system into hold-temperature mode. If the temperature of the heated object rises to a high point and then effectively decreases, failing to reach the lower limit of the process temperature during this period, the system sets the main temperature controller to the hold-temperature setting in advance, allowing the system to heat until the temperature of the heated object rises to the lower limit of the process temperature. At this point, the oven system enters hold-temperature mode.

[0065] In some embodiments, the S2 heating stage further includes the following steps:

[0066] Before monitoring the temperature to find the heating stop point, the system is in a state before heating begins, with the oven temperature close to room temperature. Input the process temperature Tg of the heated object, the process temperature tolerance ±A, and the temperature rise Tsx. After initiating the self-tuning process to find the heating stop point and monitor the temperature, the system automatically calculates the rapid heating setpoint Tzs and starts heating. When the actual temperature Tw of the heated object ≥ Tg, record this moment as t0 and shut down the heating system to allow the hot air to cool. At this time, the actual temperature Tw of the heated object continues to rise, while the air temperature Tk near the heated object in the oven begins to decrease. Periodically check the actual temperature Tw of the heated object and the air temperature Tk near the heated object in the oven. When Tw reaches the highest temperature Twg of the heated object, record this moment as t1. When Tk ≤ Tg, record this moment as t2. Calculate the heating stop correction Txx and the final heating stop point monitoring temperature Tjt using the following formula:

[0067] Heating stop correction amount: Txx=(Twg-Tg)*((t2-t0) / (t1-t0))

[0068] Monitoring temperature at the heating stop point: Tjt = Tg - Txx

[0069] Where: Twg is the highest temperature of the heated object during self-tuning, Tg is the process temperature of the heated object, t0 is the moment when the actual temperature of the heated object Tw≥Tg, t1 is the moment when the actual temperature of the heated object reaches its highest point, and t2 is the moment when the air temperature near the heated object in the oven Tk≤Tg.

[0070] Before heating, the rapid heating setpoint Tzs of the main control temperature needs to be determined in advance. This setpoint is significantly higher than the main temperature control heat preservation setpoint Tbs during heat preservation. The rapid heating setpoint is equal to the sum of the process temperature Tg of the heated object and the temperature rise Tsx (Tzs=Tg+Tsx). The temperature rise Tsx is determined manually according to the specific situation. When the rapid heating setpoint Tzs of the main control temperature is high, the actual air temperature inside the oven is also high during this stage, and the temperature difference between it and the actual temperature of the heated object is large, so the heating rate of the heated object is also fast. However, the excessively fast heating rate may have an adverse effect on the control of the heated object, or the surface of the unheated object may not be able to withstand the excessively high air temperature inside the oven. Therefore, the temperature rise Tsx is generally determined manually according to the situation. It belongs to the known conditions before the system finds the heating stop point. Other known conditions include the process temperature Tg of the heated object and the process temperature tolerance ±A. Before the system searches for the monitoring temperature, the system should be in manual mode before heating, with the temperature inside the oven close to room temperature. Input the process temperature Tg of the heated material, the process temperature tolerance ±A, and the temperature rise Tsx.

[0071] In some embodiments, the S3 heat preservation stage further includes the following steps:

[0072] S31: When the system first detects that the actual temperature TW of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, the system reads the current time as the start time t of the heat preservation process. 保启 As the insulation process continues, the system time t 系统 The actual heat preservation time t is constantly increasing. 保实 =t 系统 -t 保启 When the actual heat preservation time t 保实 ≥t 保温 When the total insulation time required by the process is reached, the S3 insulation stage ends.

[0073] The purpose of the heat preservation process is to ensure that the actual temperature of the heated object fluctuates around the process temperature. This is achieved by periodically monitoring the actual temperature of the heated object to determine the deviation between the actual temperature and the process temperature. The deviation is then integrated over time, and this integral is divided by the integration coefficient (time period) to obtain a feedback correction. This feedback correction is added to the heat preservation setpoint (the sum of the process temperature and the heat preservation correction), and the final sum is used to update the main control temperature setpoint. When the average actual temperature of the heated object is low, the temperature integral is positive, and the main control temperature setpoint is automatically increased, causing the actual temperature of the heated object to rise, and the positive temperature integral decreases until it reaches zero. Conversely, if the average temperature is high, the temperature integral becomes negative, and the main control temperature setpoint is automatically decreased, causing the actual temperature of the heated object to fall until the negative temperature integral returns to zero. By automatically adjusting the main control temperature setpoint, the actual temperature of the heated object is ensured to fluctuate around the process temperature. To ensure heating safety, the theoretical temperature control setpoint derived from the temperature integral must not exceed the maximum allowable heating temperature. If it does, the main temperature control setpoint is set according to the maximum allowable heating temperature. Specifically, during the heating phase, if the actual temperature of the heated object Tw ≥ Tg - A (the lower limit of the process temperature, Tg being the process temperature, ±A being the temperature tolerance), the system enters the heat preservation phase. The cycle number i and the initial integral M0 are initialized to zero. The current system time t is read and assigned to the heat preservation start time tpreservation start. Waiting for the next sampling cycle, the actual temperature Tw of the heated object is read, number i is incremented by 1, and the temperature deviation ΔTi = Tg - Tw (Tg being the process temperature, Tw being the actual temperature of the heated object) is calculated. The current integral Mi = Mpreservation start is also calculated. i-1 +tz*ΔT i / 1000 (M) i-1 The integral value from the previous cycle (tz is the sampling period) is used to calculate the current main temperature control setpoint Tzxi = Tbs + (1 / Kd)M. i (Tbs is the temperature control setpoint during the heat preservation stage, Tbs = Tg + Tbx, Tg is the process temperature, Tbx is the heat preservation and heating correction amount, K) d (where Tzx is the integral time coefficient) i >Tmax (Tmax is the maximum allowable heating set temperature) then Tzx i The value is assigned to Tmax to prevent excessively high oven air temperatures from negatively impacting the heated object. If Tzx... i >Tmax is not satisfied, Tzx i The value remains unchanged from the original calculation. Next, the current system time t is read. 系统 Calculate the actual heat preservation time t 实保 =t 系统 -t 保启 If the actual heat preservation time t 实保 ≥t 保温 (t)保温 If the total insulation time requirement of the process is not met, update the main temperature control setpoint to Tzx. i Wait for the next sampling cycle to maintain the heat preservation phase and repeat. If t 实保 ≥t 保温 Once the conditions are met, the cycle ends, the heat preservation process terminates, and the process proceeds to cooling or other stages.

[0074] In some embodiments, the S3 heat preservation stage further includes the following steps:

[0075] S32: When the system first detects that the actual temperature TW of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, it starts calculating the temperature deviation ΔT=Tg-Tw, integrating it over time t, correcting the integral with a coefficient, adding it to the heat preservation and heating set temperature Tbs, and resetting the main temperature control set value to the summed value. Specifically as follows:

[0076] Integral correction of main temperature control setpoint: The integration period in the above formula is from the start time t0 of heat preservation to the current time ti. In actual calculation, the temperature is sampled periodically and the incremental sum is used to calculate the integral value. The step-by-step calculation of the integral correction of the main temperature control heat preservation setpoint is as follows:

[0077] M0=0, the initial temperature difference integral during the heat preservation stage is set to 0;

[0078] Tbs=Tg+Tbx, the heat preservation and heating set temperature is equal to the sum of the process temperature of the heated object and the heat preservation and heating correction amount;

[0079] ΔT i =Tg-Tw, current t i The difference between the process temperature of the object being heated and the actual temperature of the object being heated at any given time;

[0080] M i =M i-1 +tz*ΔT i / 1000, the current temperature deviation integral is the sum of the previous integral and the current integral increment;

[0081] Tzx i =Tbs+(1 / K d M i The current main temperature control insulation execution value is equal to the sum of the current integral value divided by the integral coefficient and the insulation setting value;

[0082] Where: Tzx is the main temperature control and heat preservation execution value, Tw is the current actual temperature of the heated object, Tbs is the set temperature for the heat preservation stage, and K... d M0 is the temperature integral correction factor, in seconds; Tbx is the initial temperature difference integral during the insulation stage; and ΔT is the temperature correction amount during the insulation stage. iLet Tg be the difference between the process temperature in the i-th sampling period and the actual temperature of the object being heated, and M be the process temperature of the object being heated. i-1 The integral of temperature for the (i-1)th sampling period, tz, is the sampling period, Tzx i For the i-th sampling period, the main temperature control and insulation execution value is calculated after each temperature sampling, Tzx is used. i And update the main temperature control setting to Tzx i This continues until the S3 insulation phase ends.

[0083] During the heating phase, the system first detects that the actual temperature of the heated object, TW, is ≥ (Tg-A) (where Tg-A is the lower limit of the process temperature, Tg is the process temperature of the heated object, and ±A is the process temperature tolerance of the heated object). This indicates that the temperature control system has entered the heat preservation phase. At this time, the main temperature control setpoint is updated to the process temperature of the heated object plus a heat preservation correction (a pre-set parameter, generally positive) and a feedback correction. The feedback correction is calculated based on parameters such as the actual temperature change of the heated object and the process temperature. When the average actual temperature of the heated object is lower than the process temperature of the heated object, its temperature deviation integral over time is positive, the feedback correction is positive, the main temperature control setpoint is corrected upwards, and the temperature of the hot air in the oven near the heated object rises, causing the actual temperature of the heated object to rise. When the average actual temperature of the heated object is higher than the process temperature, its temperature deviation integral over time is negative, the feedback correction is positive, the main temperature control setpoint is corrected downwards, and the temperature of the hot air in the oven near the heated object decreases, causing the actual temperature of the heated object to decrease, thereby maintaining the actual temperature of the heated object near the process temperature. For feedback correction, when performing integral correction of temperature difference, a proportional correction of temperature difference can also be added. Under normal circumstances, integral correction of temperature difference is sufficient to meet the requirements.

[0084] A second aspect of the present invention provides a multi-feedback oven heating system for performing any one of the methods described in claims 1-6, comprising a central control unit, a heated object temperature measurement module, a main temperature control module, an air outlet temperature measurement module, and a heating execution system. The output end of the heated object temperature measurement module is connected to the central control unit, which sends the actual temperature value of the heated object to the central control unit for processing. The output end and receiving end of the central control unit are connected to the main temperature control module. The receiving end of the main temperature control module is connected to the air outlet temperature measurement module. The output end of the main temperature control module is connected to the heating execution system, which sends the air outlet temperature value to the central control unit for processing and controls the output power of the heating execution system according to the signal transmitted by the central control unit.

[0085] The temperature sensor and temperature measurement module of the heated object do not directly control the electric heater. Instead, they send the measured actual temperature value of the heated object to the central control unit for processing. Based on the processing, the central control unit controls the temperature setpoint of the main temperature controller, which then adjusts the switching action and output intensity of the electric heater to maintain a reasonable temperature gradient between the hot air temperature inside the chamber and the heated object, thereby achieving the purpose of adjusting the actual temperature of the heated object.

[0086] In some embodiments, the receiver of the heated object temperature measurement module is connected to the heated object temperature sensor, and the receiver of the air outlet temperature measurement module is connected to the air outlet main temperature control sensor.

[0087] In this embodiment, the temperature sensor of the heated object is not used to replace the main temperature sensor of the air outlet when connected to the main temperature controller. Since the heating and cooling speed of a large mass heated object is much slower than that of circulating hot air, directly connecting the temperature sensor of the heated object to the main temperature controller would cause a large fluctuation in the actual temperature of the heated object.

[0088] In some embodiments, the system further includes an internal hot air temperature measurement module, wherein the receiving end of the internal hot air temperature measurement module is connected to an internal hot air temperature sensor.

[0089] In some embodiments, an over-temperature detection temperature controller is also included. The receiver of the over-temperature detection temperature controller is connected to an over-temperature monitoring temperature sensor, and the output is connected to the heating execution system. When the temperature reaches a set value, the heating execution system is shut down. The over-temperature detection temperature controller is a necessary component according to national standards, and its purpose is to promptly shut down the heating execution system when other components in the oven malfunction and the temperature reaches a dangerous level.

[0090] See Figure 6 After the process begins, confirm that the oven temperature and the heated object are at room temperature. Input the process temperature Tg and the process boost Tsx, and update the main temperature control setpoint to Tsx + Tg (e.g., if the process temperature is 100℃ and the boost is 20℃, then the main temperature control setpoint will be 120℃). Start heating and read the current system time t. 系统 Read the actual temperature Tw of the heated object. If Tw ≥ Tg, the condition is not met. Wait for the next sampling period and continue the loop. If the condition is met, exit the loop and set the current system time t. 系统 Assign the value to the first time to reach the process temperature t0, shut down the heating system, and make the highest temperature of the heated object Twg = Tw (Tw is the current actual temperature of the heated object). The time tw when the highest temperature of the heated object occurs is equal to the current system time t. 系统 Wait for the next sampling period, then read the system time t. 系统Read the actual temperature Tw of the heated object. If the condition Tw ≥ Twg (Twg is the highest temperature of the heated object) is met, then the highest temperature of the heated object Twg = Tw, and the time tw when the highest temperature of the heated object occurs is equal to the current system time t. 系统 At this point, continue waiting for the next sampling cycle and repeat. The temperature of the heated object continues to rise after the power is cut off, and its highest temperature and the time of occurrence of the highest temperature are constantly updated. If the condition Tw ≥ Twg (Twg is the highest temperature of the heated object) is not met, it means that the current temperature has decreased from the highest point. If t 系统 If the condition -tw≥M (where M is the confirmation time of continuous temperature drop, t is the current time, and tw is the time when the highest temperature of the heated object occurs) is not met, it indicates that the temperature drop is due to an isolated incident, and the loop continues. If t 系统 The condition -tw≥M is met, indicating that the temperature of the heated object is continuously decreasing, breaking out of the local cycle. At this point, t1=tw reaches its highest value (t1 is the minimum value). Figure 5 (The time when the highest temperature of the heated object occurs), let t2 = t1 (t2 is the time when the highest temperature of the heated object occurs). Figure 5 (The time when the temperature of the medium-heated air is lower than or equal to the process temperature of the heated object at the first point), wait for the next use cycle, and read the current system time t. 系统 Read the air temperature Tk near the heated object. If Tk ≤ Tg (Tg is the process temperature of the heated object), the condition is not met, wait for the next cycle to continue the loop. If the condition is met, assign the current system time to t2 (t2 is the attached time). Figure 5 (The time when the temperature of the medium-heated air is lower than or equal to the process temperature of the heated object at the first point), calculate the heating stop correction amount Txx=(Twg-Tg)*((t2-t0) / (t1-t0)), calculate the monitoring temperature at the heating stop point Tjt=Tg-Txx, and the process of finding the monitoring point ends.

[0091] The above description is merely a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or related technologies or knowledge. Modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A method for controlling the heating of a multi-feedback oven, characterized in that: Includes the following steps: S1: Initialization phase. The operator inputs heating parameters, the system reads and executes the heating parameters, and the system determines whether the heating button is activated. When the heating button is activated, the S2 heating phase is executed. S2: Heating stage. Set the main temperature control setting value to be higher than the process temperature of the heated object. When the temperature of the heated object reaches the heating stop point monitoring temperature, turn off the heating system. At this time, the air temperature in the oven will drop and the temperature of the heated object will continue to rise. When the temperature of the heated object reaches the process temperature of the heated object, execute the S3 heat preservation stage. During the S3 heat preservation stage, the main temperature control setting is adjusted based on the actual temperature of the heated object and the heat preservation time is recorded. The S1 initialization phase also includes the following steps: S11: Operator inputs heating parameters: process temperature of heated object Tg, process temperature tolerance of heated object: ±A, holding time t 保 , Heating increase amount Tsx, Heating stop correction amount Txx, Heating heat preservation correction amount Tbx, Heating temperature drop confirmation time M, Maximum allowable heating temperature Tmax; S12: The system reads and executes the heating parameters: rapid heating set temperature: Tzs=Tg+Tsx, heat preservation heating set temperature: Tbs=Tg+Tbx, heating stop point monitoring temperature: Tjt=Tg-Txx; S13: After the heating button is activated, the main temperature control setting value Tzx is set to the rapid heating setting temperature Tzs; The S2 heating stage further includes the following steps: Before monitoring the temperature to find the heating stop point, the system is in a state before heating begins, with the oven temperature close to room temperature. Input the process temperature Tg of the heated object, the process temperature tolerance ±A, and the temperature rise Tsx. After initiating the self-tuning process to find the heating stop point and monitor the temperature, the system automatically calculates the rapid heating setpoint Tzs and starts heating. When the actual temperature Tw of the heated object ≥ Tg, record this moment as t0 and shut down the heating system to allow the hot air to cool. At this time, the actual temperature Tw of the heated object continues to rise, while the air temperature Tk near the heated object in the oven begins to decrease. Periodically check the actual temperature Tw of the heated object and the air temperature Tk near the heated object in the oven. When Tw reaches the highest temperature Twg of the heated object, record this moment as t1. When Tk ≤ Tg, record this moment as t2. Calculate the heating stop correction Txx and the final heating stop point monitoring temperature Tjt using the following formula: Heating stop correction amount: Txx=(Twg-Tg)*((t2-t0) / (t1-t0)) Monitoring temperature at the heating stop point: Tjt = Tg - Txx Where: Twg is the highest temperature of the heated object during self-tuning, Tg is the process temperature of the heated object, t0 is the moment when the actual temperature of the heated object Tw≥Tg, t1 is the moment when the actual temperature of the heated object reaches its highest point, and t2 is the moment when the air temperature near the heated object in the oven Tk≤Tg.

2. The multi-feedback oven heating control method according to claim 1, characterized in that: The S2 heating stage further includes the following steps: When the heating system is turned off, if the temperature of the heated object reaches a peak and then continues to drop, and the drop time is greater than or equal to the temperature drop confirmation time M, and the temperature of the heated object cannot reach the process temperature Tg, active heating will be initiated in advance. The main temperature control setpoint will be set to the heat preservation heating setpoint. The difference between the process temperature and the actual temperature of the heated object will be calculated and integrated over time. The main temperature control setpoint will be corrected using this processed value until the temperature of the heated object reaches the process temperature Tg. At this time, the heat preservation stage S3 will begin, and the heat preservation timer will be started.

3. The multi-feedback oven heating control method according to claim 1, characterized in that: The S3 heat preservation stage also includes the following steps: S31: When the system first detects that the actual temperature Tw of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, the system reads the current time as the start time t of the heat preservation process. 保启 As the insulation process continues, the system time t 系统 The actual heat preservation time t is constantly increasing. 保实 =t 系统 -t 保启 When the actual heat preservation time t 保实 ≥t 保 When the required insulation time is reached, the S3 insulation stage ends.

4. The multi-feedback oven heating control method according to claim 1, characterized in that: The S3 heat preservation stage also includes the following steps: S32: When the system first detects that the actual temperature Tw of the heated object is greater than or equal to the lower limit of the process temperature Tg-A, it starts calculating the temperature deviation ΔT=Tg-Tw, integrating it over time t, correcting the integral with a coefficient, adding it to the heat preservation and heating set temperature Tbs, and resetting the main temperature control set value to the summed value. Specifically as follows: Integral correction of main temperature control setpoint: The integration period in the above formula is from the start time t0 of heat preservation to the current time ti. In actual calculation, the temperature is sampled periodically and the incremental sum is used to calculate the integral value. The step-by-step calculation of the integral correction of the main temperature control heat preservation setpoint is as follows: M0=0, the initial temperature difference integral during the heat preservation stage is set to 0; Tbs=Tg+Tbx, the heat preservation and heating set temperature is equal to the sum of the process temperature of the heated object and the heat preservation and heating correction amount; ΔT i =Tg-Tw, current t i The difference between the process temperature of the object being heated and the actual temperature of the object being heated at any given time; M i =M i-1 +tz*ΔT i / 1000, the current temperature difference integral is the temperature difference integral of the previous moment plus the current integral increment; Tzx i =Tbs+(1 / K d M i The current main temperature control insulation execution value is equal to the sum of the current temperature difference integral divided by the temperature integral correction coefficient and the insulation heating set temperature. Where: Tzx is the main temperature control and heat preservation execution value, Tw is the current actual temperature of the heated object, Tbs is the heat preservation and heating set temperature, and K... d M0 is the temperature integral correction factor, in seconds; Tbx is the initial temperature difference integral during the heat preservation stage; and ΔT is the heat preservation and heating correction amount. i Let Tg be the difference between the process temperature of the heated object in the i-th sampling period and the current actual temperature of the heated object, where Tg is the process temperature of the heated object, and M is the temperature of the heated object. i-1 The integral of the temperature difference during the (i-1)th sampling period, tz, is the sampling period, Tzx i For the i-th sampling period, the main temperature control and insulation execution value is calculated after each temperature sampling, Tzx is used. i And update the main temperature control setting to Tzx i This continues until the S3 insulation phase ends.

5. A multi-feedback oven heating system, used to execute the multi-feedback oven heating control method as described in any one of claims 1-4, characterized in that: The system includes a central control unit, a heated object temperature measurement module, a main temperature control module, an air outlet temperature measurement module, and a heating execution system. The output of the heated object temperature measurement module is connected to the central control unit, which sends the actual temperature value of the heated object to the central control unit for processing. The output and receiving ends of the central control unit are connected to the main temperature control module. The receiving end of the main temperature control module is connected to the air outlet temperature measurement module. The output of the main temperature control module is connected to the heating execution system, which sends the air outlet temperature value to the central control unit for processing and controls the output power of the heating execution system based on the signal transmitted by the central control unit.

6. The multi-feedback oven heating system according to claim 5, characterized in that: The receiving end of the heated object temperature measurement module is connected to the heated object temperature sensor, and the receiving end of the air outlet temperature measurement module is connected to the air outlet main temperature control sensor.

7. The multi-feedback oven heating system according to claim 5, characterized in that: It also includes an internal hot air temperature measurement module, the receiver of which is connected to an internal hot air temperature sensor.

8. The multi-feedback oven heating system according to claim 5, characterized in that: It also includes an over-temperature detection and temperature control instrument. The receiving end of the over-temperature detection and temperature control instrument is connected to the over-temperature monitoring temperature sensor, and the output end is connected to the heating execution system. When the temperature reaches the set value, the heating execution system is turned off.

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