Duty cycle-based temperature control method, control device, and storage medium

Abstract

This invention relates to a duty cycle-based temperature control method, control device, and storage medium. The method operates on a heating device and includes: acquiring the duty cycles of the heating device and a reference device stabilized at a first set temperature; obtaining a correction coefficient based on the duty cycles of the heating device and the reference device at the first set temperature; obtaining an initial duty cycle of the heating device at the target set temperature based on the correction coefficient, the target set temperature, and the correlation between the duty cycle of the reference device and the target set temperature, wherein the target set temperature is the desired temperature reached by the heating device after heating in response to user operation; and adjusting the current temperature of the heating device based on the initial duty cycle and using a proportional-integral-differential algorithm to bring the current temperature to the target set temperature. This solution improves the temperature control accuracy and speed of a steam oven, thereby enhancing the user experience and the working efficiency of the heating device.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology, and specifically provides a temperature control method, control device, and storage medium based on duty cycle. Background Technology

[0002] In PWM temperature control, duty cycle directly reflects the power level. As the demands on heating equipment increase, the ability of heating equipment to provide the optimal duty cycle at different target temperatures has become an important criterion for evaluating its quality.

[0003] In existing technologies, taking steam ovens as an example, in order to find the most suitable duty cycle for different target set temperatures during temperature control, steam ovens typically need to conduct multiple experiments to find the optimal duty cycle for each target set temperature. However, this approach is time-consuming and it is impossible to measure the optimal duty cycle for every single target set temperature.

[0004] Accordingly, a new temperature control solution is needed in this field to address the aforementioned problems. Summary of the Invention

[0005] To overcome the above-mentioned shortcomings, the present invention is proposed to provide a solution, or at least a partial solution, to the problem in the prior art that temperature control requires a large amount of time to determine the optimal duty cycle corresponding to different target set temperatures.

[0006] In a first aspect, the present invention provides a temperature control method based on duty cycle, the method being applied to a heating device, comprising: acquiring the duty cycles of the heating device and a reference device stabilized at a first set temperature; obtaining a correction coefficient based on the duty cycles of the heating device and the reference device at the first set temperature; obtaining an initial duty cycle of the heating device at the target set temperature based on the correction coefficient, a target set temperature, and the correlation between the duty cycle of the reference device and the target set temperature, wherein the target set temperature is a target desired temperature reached by the heating device after heating in response to a user operation; and adjusting the current temperature of the heating device based on the initial duty cycle and using a proportional-integral-differential algorithm to make the current temperature reach the target set temperature.

[0007] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present invention, before regulating the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm, the method further includes: responding to a control command to heat to a target set temperature, performing heating at full load power; determining whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a first preset threshold; the regulation of the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm includes: if the absolute value of the difference between the current temperature and the target set temperature is less than or equal to the first preset threshold, then regulating the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm.

[0008] As an alternative or supplement to the above solutions, in a method according to an embodiment of the present invention, the step of obtaining the duty cycles of the heating device and the reference device stable at a first set temperature includes: obtaining a first duty cycle of the heating device stable at a first set temperature; obtaining a correlation between the duty cycle of the reference device and the target set temperature; obtaining a second duty cycle of the reference device at the first set temperature based on the correlation and the first set temperature; the step of obtaining a correction coefficient based on the duty cycles of the heating device and the reference device at the first set temperature includes: obtaining a correction coefficient based on the first duty cycle and the second duty cycle.

[0009] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present invention, the step of regulating the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm includes: determining an initial value of the cumulative deviation in the proportional-integral-differential algorithm according to the ratio of the initial duty cycle and a preset integral parameter; and regulating the current temperature using a proportional-integral-differential algorithm based on the initial value of the cumulative deviation.

[0010] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present invention, after adjusting the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm, the method further includes: determining whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a second preset threshold within a preset time period; if so, determining that the temperature stabilization stage has been entered.

[0011] As an alternative or supplement to the above scheme, in a method according to an embodiment of the present invention, the method further includes: when entering the temperature stabilization stage, using a combination of proportional-integral-derivative (PID) parameters different from the control stage that regulates the current temperature based on the proportional-integral-derivative (PID) algorithm, wherein at least one parameter in the PID parameter combination has a value less than the value of the corresponding parameter in the control stage.

[0012] As an alternative or supplement to the above solutions, in a method according to an embodiment of the present invention, the step of using a proportional-integral-derivative (PID) parameter combination for temperature control, which is different from the control stage based on the proportional-integral-derivative (PID) algorithm for regulating the current temperature, includes: when the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a second preset threshold, using a first PID parameter combination for temperature control; when the absolute value of the difference between the current temperature and the target set temperature is greater than the second preset threshold and less than or equal to a third preset threshold, using a second PID parameter combination for temperature control, wherein at least one parameter in the second PID parameter combination has a value greater than the value of the corresponding parameter in the second PID parameter combination.

[0013] As an alternative or supplement to the above solutions, in a method according to an embodiment of the present invention,

[0014] In a second aspect, a control device is provided, comprising a processor and a storage device, the storage device being adapted to store a plurality of computer programs, the computer programs being adapted to be loaded and run by the processor to perform the duty cycle-based temperature control method described in any of the above-described technical solutions.

[0015] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of computer programs are stored therein, the computer programs being adapted to be loaded and run by a processor to perform the duty cycle-based temperature control method described in any of the above-described technical solutions.

[0016] In a fourth aspect, a heating device is provided, including a temperature sensor and a control device, wherein the temperature sensor is used to detect the current temperature inside the heating device; and the control device is used to execute the duty cycle-based temperature control method described in any of the above-described technical solutions.

[0017] The present invention comprises one or more of the following technical solutions:

[0018] Beneficial effects:

[0019] In implementing the technical solution of this invention, a correction coefficient is obtained by acquiring the duty cycles of the heating device and the reference device at a specific target set temperature, thus obtaining the optimal initial duty cycle corresponding to that specific target set temperature. This avoids the technical problem in the prior art of needing to conduct multiple experiments to find the optimal duty cycle corresponding to the target set temperature. Using a proportional-integral-differential algorithm, temperature control is performed based on this optimal initial duty cycle, achieving more precise and faster temperature control. This solution solves the technical problem in the prior art of not easily finding the optimal duty cycle corresponding to the target set temperature, improving the temperature control accuracy and speed of the steam oven, thereby enhancing the user experience and the working efficiency of the heating device. Attached Figure Description

[0020] The disclosure of this invention will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. Furthermore, similar numbers in the drawings are used to denote similar components, wherein:

[0021] Figure 1 This is a schematic flowchart of the main steps of a temperature control method based on duty cycle according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic flowchart of the minor steps of a temperature control method based on duty cycle according to an embodiment of the present invention. Detailed Implementation

[0023] Some embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0024] In the description of this invention, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and may also include software components, such as computer programs, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Non-transitory computer-readable storage media includes any suitable medium capable of storing computer programs, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B, or A and B. The terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0025] See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a duty cycle-based temperature control method according to an embodiment of the present invention. Figure 1 As shown, the temperature control method based on duty cycle in this embodiment of the invention mainly includes the following steps S10-S40.

[0026] Step S10: Obtain the duty cycle of the heating device and the reference device that are stable at the first set temperature.

[0027] In this embodiment, the PWM duty cycle of the heating device and the reference device is obtained under specific temperature conditions.

[0028] In one embodiment, taking a steam oven as an example, the duty cycle of the steam oven at a stable first set temperature is obtained. PWM (Pulse Width Modulation) is a method commonly used to control the output power of digital systems. Its basic principle is to change the duty cycle of the output signal to control its output power. In this embodiment, the PWM value is the duty cycle value, which is mainly used to control the heating element of the steam oven. By adjusting the duty cycle, the heating intensity of the heating element can be changed, thereby controlling the temperature inside the oven.

[0029] In this embodiment, the duty cycles of the heating device and the reference device at the first set temperature are obtained through steps S101-S103, such as... Figure 2 As shown, the details are as follows:

[0030] Step S101: Obtain the first duty cycle of the heating device that is stable at the first set temperature.

[0031] In this embodiment, the first set temperature is set in order to obtain a correction coefficient.

[0032] In one implementation, the steam oven is set to a first preset temperature. For example, if the first preset temperature is set to 180°C, the steam oven is adjusted to this temperature. Since the first preset temperature is within the commonly used operating range of the steam oven, the data obtained in this way can effectively reflect the normal performance of the heating equipment.

[0033] After the temperature is set, the steam oven begins heating until its internal temperature reaches and stabilizes at the first set temperature. Based on this, the duty cycle of the steam oven at the first set temperature is measured and calculated. Specifically, the operating status of the heating element can be obtained through the steam oven's control system, recording the working and resting times of the heating element in each time cycle, and then the duty cycle is calculated.

[0034] Step S102: Obtain the correlation between the duty cycle of the reference device and the target set temperature.

[0035] In this embodiment, the reference device is a standard or benchmark heating device, whose behavior and characteristics are used to compare with other heating devices or as a setting reference. The correlation refers to the mathematical or functional relationship between the duty cycle of the reference device and the target set temperature.

[0036] One embodiment provides a method for obtaining the correlation. Preferably, in this embodiment, a series of tests are performed on the reference device, with different operating temperatures set, such as 150°C, 180°C, 200°C, etc. At each target set temperature, the reference device is allowed to operate and reach a stable state, and then the duty cycle at this time is measured and recorded. In this way, the duty cycle at each target set temperature is obtained, forming a set of duty cycle and target set temperature data.

[0037] Next, based on this data, a mathematical model or functional relationship between the duty cycle and the target set temperature can be established using statistical analysis methods (such as linear regression, polynomial fitting, etc.). For example, assuming that the relationship between the duty cycle and the target set temperature is linear, a straight line can be obtained using linear regression. The slope and intercept of this line describe the law of duty cycle variation with the target set temperature.

[0038] To facilitate understanding of this implementation method, an example is given here. For instance, a steam oven is selected for testing, and at least two different target set temperatures are set.

[0039] For each target set temperature, measure and record the duty cycle of the steam oven when it reaches a steady state. Here, steady state refers to the proportion of the total time the heating element is on when the oven temperature finally stabilizes at the target set temperature.

[0040] Using the target set temperature as the independent variable X and the corresponding duty cycle as the dependent variable Y, a fit is performed to obtain a function of Y versus X. In this embodiment, linear fit data is obtained, i.e., Y = a*X + b, where a and b are the fitting coefficients.

[0041] Thus, the initial PWM fitting coefficients a and b for this steam oven under this heat pipe (heating element) combination are obtained. These fitting coefficients are obtained based on actual measurement data, and therefore can accurately reflect the actual behavior of the steam oven at different target set temperatures.

[0042] The above steps are repeated for all heating element combinations to obtain the PWM fitting coefficients a and b for each combination. These coefficients a and b are recorded and used as parameters for the reference device, and are not changed after leaving the factory.

[0043] Whenever the system needs to calculate the PWM of the reference device, it can use these coefficients a and b in combination with the set first temperature to calculate the initial PWM value of the reference device at this time.

[0044] This establishes the correlation between the duty cycle of the reference device and the target set temperature. This correlation will be used in subsequent steps to calculate the theoretical duty cycle of the reference device at a given temperature, which is crucial for calculating the correction factor.

[0045] In this embodiment, the duty cycle of the reference device at the target set temperature is calculated using fitting coefficients and fitting relationships. This method is simple, clear, easy to understand and operate. Furthermore, coefficients a and b only need to be measured and recorded once during the manufacturing process and then permanently stored in the heating device. They do not need to be remeasured and calculated every time they are used, which improves the convenience of the calculation.

[0046] Step S103: Based on the correlation and the first set temperature, obtain the second duty cycle of the reference device at the first set temperature.

[0047] In this embodiment, the theoretical duty cycle of the reference device at the first set temperature is referred to as the second duty cycle.

[0048] In one implementation, the correlation obtained from step S102 is used, for example, Y = a*X + b. Then, the first set temperature is substituted into this correlation to calculate the theoretical duty cycle of the reference device at the first set temperature, i.e., the second duty cycle. This duty cycle is the duty cycle of the reference device when it reaches a steady state and at the first set temperature; it reflects the power required by the reference device at this temperature.

[0049] In this embodiment, the theoretical duty cycle of the reference device at other temperatures is predicted based on this correlation, eliminating the need to conduct experiments on every heating device at every temperature, thereby reducing the number of experiments and saving time and resources.

[0050] Step S20: Obtain the correction coefficient based on the duty cycle of the heating device and the reference device at the first set temperature.

[0051] In this embodiment, the correction factor will be used to correct the initial PWM value of the heating device to more accurately reflect its performance under actual operating conditions.

[0052] In one embodiment, the correction factor is represented by α. In this embodiment, the correction factor is obtained based on the first duty cycle and the second duty cycle. It should be noted that the PWM value of the reference device is obtained by fitting the reference device at different target set temperatures. However, in practical applications, due to design and manufacturing differences between different models of steam ovens, the PWM values ​​of different models of steam ovens may differ even at the same target set temperature. Performing separate measurements and calculations for each model of steam oven would undoubtedly result in significant experimental costs and time consumption.

[0053] To address this issue, a correction factor α is introduced to correct the PWM value obtained based on the reference device's correlation. In this embodiment, the correction factor α is set according to the proportional relationship between the actual PWM value of the target heating device (heating equipment) in a steady state and the PWM value calculated by the reference device at the same temperature. Specifically, it is calculated by dividing the first duty cycle of the target heating device by the second duty cycle of the reference device: α = first duty cycle / second duty cycle. This calculation method yields a correction factor that describes the proportional relationship between the duty cycles of the target heating device and the reference device at the same target set temperature.

[0054] In this embodiment, if the actual PWM value of the target heating device is greater than the PWM value calculated by the reference device, then the correction coefficient α should be greater than 1; conversely, if the PWM value of the target heating device is less than the PWM value calculated by the reference device, then the correction coefficient α should be less than 1.

[0055] The correction factor α will be used in subsequent steps to correct the initial PWM value of the target heating device. By using this correction factor, the temperature control of the target heating device can be optimized based on the performance and characteristics of the reference device, enabling the target heating device to reach the set temperature more accurately and quickly.

[0056] Step S30: Based on the correction coefficient, the target set temperature, and the correlation between the duty cycle of the reference device and the target set temperature, obtain the initial duty cycle of the heating device at the target set temperature.

[0057] In this embodiment, the target set temperature is the desired temperature reached by the heating device after heating in response to user operation. The correlation between the duty cycle of the reference device and the target set temperature is the same as in step S102, and will not be repeated here.

[0058] In one implementation, the target set temperature is the temperature the user desires the oven to reach. This temperature will be used as a reference point for the control system to determine how the system should adjust to achieve that set value. For example, if the user sets the target set temperature to 200°C, the control system will take necessary actions (such as turning on the heating element) to raise the actual temperature inside the oven to that set value.

[0059] In this embodiment, the initial duty cycle of the heating device at the target set temperature can be obtained by using the correction coefficient, the target set temperature, and the correlation between the duty cycle of the reference device and the target set temperature. Once the correction coefficient and the correlation between the duty cycle of the reference device and the target set temperature are determined, the initial duty cycle can be obtained by substituting the value of the target set temperature.

[0060] From one perspective, this step can be understood as follows: Using the known correlation between the duty cycle of the reference device and the target set temperature, the expected duty cycle of the reference device at the target set temperature is calculated. Then, the expected duty cycle is multiplied by a correction factor α to obtain the initial duty cycle of the target heating device at the target set temperature. Mathematically, if the expected duty cycle of the reference device at the target set temperature is P, then the initial duty cycle of the target heating device at the target set temperature is αP.

[0061] This example illustrates the concept of two steam ovens: a reference device A used for parameter measurement, and a target steam oven (heating device) B for which a temperature control system is applied. The PWM fitting coefficients a and b of reference device A are known. Based on this, the theoretical PWM value of reference device A at a target set temperature of 200 degrees Celsius can be calculated using the formula Y = a*X + b, resulting in 50%.

[0062] Then, the target steam oven B was set to the same 200 degrees Celsius, and its PWM value under steady-state conditions was measured. It was found that the actual PWM value of steam oven B was 55% in order to achieve and maintain the target set temperature of 200 degrees Celsius.

[0063] In this example, the correction factor α is calculated to be 1.1. This means that for steam oven B, the theoretical PWM value of the reference device A needs to be multiplied by this correction factor α to obtain the initial PWM value of steam oven B. Once the correction factor α is obtained, the theoretical PWM value corresponding to any target set temperature in the target steam oven B can be predicted using the new formula Y = (a*X + b)*α. Specifically, the target set temperature is substituted into the new formula. This new formula is actually a correction based on the theoretical PWM value of the reference device A, adjusted according to the actual situation of the target steam oven B. In this way, a PWM value closer to the actual needs of steam oven B can be obtained.

[0064] In this way, the correction coefficient α can help adjust the initial PWM value according to the actual situation of the target steam oven, making it closer to the actual required PWM value, so that the steam oven can reach the set target temperature more quickly when entering the adjustment stage.

[0065] This yields the initial duty cycle of the target heating device at the target set temperature. This initial duty cycle will be used for the next temperature adjustment step, serving as the initial input to the PID control algorithm.

[0066] Step S40: Based on the initial duty cycle, the current temperature is adjusted using a proportional-integral-differential algorithm to bring the current temperature to the target set temperature.

[0067] In this embodiment, the current temperature is the actual temperature of the oven as read by the temperature sensor inside the heating device.

[0068] It's important to note that temperature sensors are typically located in a specific area of ​​the oven, enabling them to accurately read the internal temperature. However, as the oven heats up or cools down, the internal temperature can vary because different areas may heat up or cool down at different rates. For example, areas closer to the heating elements may be hotter, while areas farther away may be colder. In such cases, the temperature read by the sensor may only represent the temperature of a specific part of the oven, and not necessarily the average temperature or the temperature of the target baking location (e.g., the center of the oven).

[0069] Furthermore, different combinations of heating elements can lead to different temperature distribution patterns. For example, if only the upper heating element is working, the temperature at the top of the oven may be higher than the temperature at the bottom. If both the upper and lower heating elements are working, the temperature inside the oven may be more uniform. Therefore, the relationship between the oven's current temperature and the temperature at the center of the oven may vary depending on the combination of heating elements, exhibiting a certain degree of mapping.

[0070] Therefore, in actual operation, different heating modes need to consider different mapping relationships. In this embodiment, this mapping relationship is fitted by experimental data to determine the oven's heating strategy and temperature control algorithm in order to achieve the baking effect expected by the user.

[0071] The Proportional-Integral-Derivative (PID) algorithm consists of three parameters: proportional (P), integral (I), and derivative (D). These parameters affect the system's control performance, such as response speed, stability, and steady-state error elimination.

[0072] In one implementation, the parameters in the PID controller also include integral speeds (EskAs), where the integral speed is a factor influencing the integral coefficients and determines the rate at which the system accumulates error under static error conditions. The role of this integral speed is detailed here. In this embodiment, the integral coefficients are an important part of the PID controller, helping to eliminate so-called steady-state error, which is the persistent deviation between the expected output and the actual output after the system reaches a steady state. However, excessively strong integral action can lead to overshoot and oscillations in the system. The role of the integral speed is to control this, adjusting the influence of integral control to maintain system stability while eliminating steady-state error.

[0073] For example, if the integral speed value is set to 0, the effect of integral control no longer changes. That is, the PID controller will no longer perform integral accumulation calculations, but will instead use the integral term value from the previous step. For example, when a faster response is desired and small steady-state errors are not a major concern, this setting can prevent the rapid accumulation of integral values ​​during faster responses, thus avoiding errors in subsequent judgments.

[0074] The integral velocity acts on the integral coefficient, so in this embodiment, the integral coefficient mentioned later will include the integral velocity by default.

[0075] In this embodiment, the current temperature is controlled based on the initial duty cycle and using a proportional-integral-differential algorithm. Through meticulous adjustments, the internal temperature of the heating device can accurately reach the target temperature set by the user and remain stable at this temperature.

[0076] At the beginning of the adjustment phase, a preset initial integral value is given to the PID controller, which is the initial cumulative deviation value, or the initial duty cycle. This initial duty cycle is calculated based on the stable duty cycle of the heating equipment at the target set temperature.

[0077] The adjustment phase can be divided into one or more stages. It should be noted that in actual operation, the temperature control process may be affected by many factors, such as the dynamic characteristics of the system, changes in ambient temperature, and user operation.

[0078] In this embodiment, to address different influences, the control system preferably divides the adjustment phase into multiple sub-phases, each with its own objectives and strategies. For example, in this embodiment, the adjustment phase has three sub-phases: a "rapid adjustment" phase, a "fine-tuning" phase, and a "maintaining stability" phase.

[0079] First, the system enters a "rapid adjustment" phase, where the controller parameters are set to relatively large values ​​to quickly reduce the difference between the actual temperature and the target set temperature. After certain conditions are met, the system enters a "fine-tuning" phase, where the controller parameters are set to smaller values ​​to reduce over-adjustment and oscillation of the temperature. Finally, the system enters a "maintain stability" phase, where the controller parameters are set to moderate values ​​to maintain temperature stability.

[0080] In this embodiment, specifically, the initial duty cycle is introduced into the control through steps S401-402.

[0081] Step S401: Determine the initial value of the cumulative deviation in the proportional-integral-derivative algorithm based on the ratio of the initial duty cycle to the preset integral parameter.

[0082] In this embodiment, the cumulative deviation, also known as the integral term, represents the accumulation of all past deviation values.

[0083] In one implementation, the initial duty cycle of the heating device is multiplied by a preset integral parameter, and the result is the initial value of the cumulative deviation. This calculation process can be expressed as: Initial value of cumulative deviation = Initial duty cycle * Preset integral parameter.

[0084] Step S402: Based on the initial value of the cumulative deviation, the current temperature is controlled using a proportional-integral-differential algorithm.

[0085] In one implementation, the purpose of using an initial cumulative deviation value to regulate the current temperature is to prevent a large temperature rebound in the system when it first enters this stage, which would affect the steaming and baking effect.

[0086] Step S501: Determine whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to the second preset threshold within a preset time period.

[0087] In this embodiment, both the preset duration and the second preset threshold can be flexibly set according to requirements.

[0088] Step S502: If yes, confirm that the temperature has entered the stabilization phase.

[0089] When the temperature stabilizes, a different combination of proportional-integral-derivative (PID) parameters is used for temperature control compared to the control phase which uses a proportional-integral-derivative (PID) algorithm to regulate the current temperature. In this combination, at least one parameter has a value less than the corresponding parameter value in the control phase.

[0090] Similar to the adjustment phase, the temperature stabilization phase can also have one or more sub-phases. Preferably, in this embodiment, the temperature stabilization phase is divided into two smaller phases. Specifically, when the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a second preset threshold, temperature control is performed using a first proportional-integral-derivative parameter combination. In this phase, the proportional coefficient (P), integral coefficient (I), and derivative coefficient (D) are set smaller, mainly to minimize small temperature fluctuations, and the integral rate (EskAs) may be set smaller to reduce fluctuations.

[0091] When the absolute value of the difference between the current temperature and the target set temperature is greater than the second preset threshold and less than or equal to the third preset threshold, temperature control is performed using a second proportional-integral-derivative (PID) parameter combination. In this combination, at least one parameter has a value greater than the corresponding parameter in the second PID parameter combination. During this stage, one or more of the proportional coefficient (P), integral coefficient (I), or derivative coefficient (D) will be appropriately increased to enable faster response and adjustment to temperature deviations. Simultaneously, the integral speed (EskAs) may be set relatively high for rapid regulation.

[0092] The stable temperature phase is the final stage in the entire temperature control process. It's designed to maintain the oven temperature at the preset target temperature and prevent large temperature fluctuations. During this phase, the adjustment function of the PID controller is gradually weakened, especially the proportional (P) and derivative (D) controls, to avoid temperature oscillations caused by excessively rapid responses.

[0093] Here's an example. During the temperature stabilization phase, assume the oven has reached the set temperature of 200℃ and has already undergone precise temperature adjustments during the adjustment phase. The main goal of this phase is to ensure stable oven temperature and minimize temperature fluctuations.

[0094] The temperature stabilization phase is divided into two sub-phases: Phase 1 and Phase 2.

[0095] Phase 1: Phase 1 begins when the actual temperature inside the oven deviates from the target set temperature within a certain range, such as ±2℃. In this phase, the primary goal is to minimize small temperature fluctuations; therefore, the proportional (P), integral (I), and derivative (D) coefficients of the PID controller may be set relatively small. For example, P could be set to 0.5, I to 1, and D to 0. Simultaneously, to eliminate small steady-state temperature differences, the integral rate (EskAs) may be set relatively small, such as 0.1.

[0096] Phase 2: If the actual temperature inside the oven deviates from the target set temperature by more than ±2℃ but less than ±10℃, Phase 2 will be initiated. In this phase, a faster response and adjustment to the temperature deviation is required. Therefore, the proportional gain (P) and derivative gain (D) may be moderately increased, for example, P is set to 1, I to 1, and D to 0. Simultaneously, the integral gain (I) is set relatively large, such as 0.4.

[0097] These two stages will automatically switch based on the deviation between the actual temperature inside the oven and the target set temperature, ensuring that the steam oven maintains a stable temperature throughout the cooking process.

[0098] This sophisticated control strategy enables the steam oven to maintain high precision and stable temperature control under various cooking conditions, thereby ensuring consistent cooking quality and food taste.

[0099] In this embodiment, before adjusting the current temperature based on the initial duty cycle and using the proportional-integral-differential algorithm, steps S601-602 are included, which are the heating stage of the heating device.

[0100] It should be noted that when the absolute value of the difference between the current temperature and the target set temperature is greater than the third preset threshold, the system will return to the adjustment state.

[0101] Step S601: In response to the control command to heat to the target set temperature, heating is performed at full load power.

[0102] In one implementation, the main task of the system at this stage is to bring the heating device to the set temperature as quickly as possible. To achieve this goal, the heating element assembly used at this stage will operate at full power or maintain a high power to raise the temperature of the heating device to the target set temperature as quickly as possible.

[0103] In this step, the system does not use a PID algorithm for control because speed is the most critical factor at this stage. This design aims to ensure the steam oven reaches the target set temperature as quickly as possible. Therefore, the selected heating element combination will be activated and operate at maximum power to rapidly increase the internal temperature of the steam oven.

[0104] However, the specific strategy for fully opening the heating elements is controlled by the oven's "rapid heating" switch. If the "rapid heating" switch is on, the system will use the maximum power combination of heating elements to raise the temperature. If the "rapid heating" switch is off, the system will use the normal combination of heating elements to raise the temperature. But in either case, the goal at this stage is to raise the temperature as quickly as possible.

[0105] It should be noted that the heating phase ends when the current temperature of the heating device reaches the preset full-opening stop point. At this time, the current temperature will continue to rise due to inertia and then drop. When the temperature condition meets the requirements of step S602, step S40 will be executed. The temperature setting of the full-opening stop point is positively correlated with the target set temperature. In this embodiment, the relationship between the full-opening stop point and the target set temperature is obtained in advance by fitting experimental data, and then the corresponding full-opening stop point is calculated based on the target set temperature.

[0106] Step S602: Determine whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to the first preset threshold.

[0107] In one implementation, this step is a condition for activating PID control, namely, the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a first preset threshold, indicating that the temperature of the heating device is approximately close to the target set temperature. In this case, the system will proceed to the next step, which is to adjust the temperature based on the initial duty cycle and using a proportional-integral-derivative (PID) algorithm.

[0108] If the absolute value of the difference between the current temperature and the target set temperature is less than or equal to the first preset threshold, then proceed to step S40.

[0109] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effects of the present invention, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders, and these variations are all within the scope of protection of the present invention.

[0110] Those skilled in the art will understand that all or part of the processes in the method of the above-described embodiment of the present invention can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes other computer programs, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable storage medium can include any entity or device capable of carrying the computer program, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc. It should be noted that the content included in the computer-readable storage medium can be appropriately added to or subtracted according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0111] Furthermore, the present invention also provides a control device. In one embodiment of the control device according to the present invention, the control device includes a processor and a storage device. The storage device can be configured to store a program for executing the duty cycle-based temperature control method of the above-described method embodiments. The processor can be configured to execute the program in the storage device, which includes, but is not limited to, a program for executing the duty cycle-based temperature control method of the above-described method embodiments. For ease of explanation, only the parts related to the embodiments of the present invention are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of the present invention. The control device can be a control device heating device comprising various electronic heating devices.

[0112] Furthermore, the present invention also provides a computer-readable storage medium. In one embodiment of the computer-readable storage medium according to the present invention, the computer-readable storage medium can be configured to store a program that performs the duty cycle-based temperature control method of the above-described method embodiments. This program can be loaded and run by a processor to implement the above-described duty cycle-based temperature control method. For ease of explanation, only the parts related to the embodiments of the present invention are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of the present invention. The computer-readable storage medium can be a storage device heating device comprising various electronic heating devices. Optionally, in the embodiments of the present invention, the computer-readable storage medium is a non-transitory computer-readable storage medium.

[0113] Furthermore, the present invention also provides a heating device, including a temperature sensor and a control device, wherein the temperature sensor is used to detect the current temperature inside the heating device; and the control device is used to execute the duty cycle-based temperature control method described in any of the above-described technical solutions.

[0114] Furthermore, it should be understood that since the various modules are only provided to illustrate the functional units of the device of the present invention, the physical devices corresponding to these modules may be the processor itself, or a part of the processor's software, hardware, or a combination of software and hardware. Therefore, the number of modules shown in the figures is merely illustrative.

[0115] Those skilled in the art will understand that the various modules in the device can be adaptively split or combined. Such splitting or combining of specific modules will not cause the technical solution to deviate from the principles of the present invention; therefore, the technical solutions after splitting or combining will fall within the protection scope of the present invention.

[0116] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A temperature control method based on duty cycle, characterized in that, Acting on heating equipment, including: The duty cycles of the heating device and the reference device, which are stable at the first set temperature, are obtained respectively. Based on the duty cycle of the heating device and the reference device at the first set temperature, a correction coefficient is obtained; Based on the correction coefficient, the target set temperature, and the correlation between the duty cycle of the reference device and the target set temperature, the initial duty cycle of the heating device at the target set temperature is obtained, wherein the target set temperature is the target desired temperature reached by the heating device after heating in response to user operation; Based on the initial duty cycle, the current temperature of the heating device is adjusted using a proportional-integral-differential algorithm to bring the current temperature to the target set temperature. The step of obtaining the duty cycles of the heating device and the reference device, respectively, at a stable first set temperature includes: Obtain a first duty cycle of the heating device that is stable at a first set temperature; Obtain the correlation between the duty cycle of the reference device and the target set temperature; Based on the aforementioned correlation and the first set temperature, the second duty cycle of the reference device at the first set temperature is obtained.

2. The temperature control method based on duty cycle according to claim 1, characterized in that, Before adjusting the current temperature of the heating device based on the initial duty cycle and using a proportional-integral-differential algorithm, the method further includes: In response to a control command to heat to the target set temperature, the system performs heating at full load power. Determine whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a first preset threshold. If so, then execute "Based on the initial duty cycle, adjust the current temperature of the heating device using a proportional-integral-differential algorithm".

3. The temperature control method based on duty cycle according to claim 1, characterized in that, The correction coefficient is obtained based on the duty cycle of the heating device and the reference device at the first set temperature, including: The correction coefficient is obtained based on the ratio of the first duty cycle to the second duty cycle.

4. The temperature control method based on duty cycle according to any one of claims 1-3, characterized in that, The method of regulating the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm includes: The initial value of the cumulative deviation in the proportional-integral-differential algorithm is determined based on the ratio of the initial duty cycle to the preset integration parameter. Based on the initial value of the cumulative deviation, the current temperature is controlled using a proportional-integral-differential algorithm.

5. The temperature control method based on duty cycle according to any one of claims 1-3, characterized in that, After adjusting the current temperature based on the initial duty cycle and using a proportional-integral-differential algorithm, the method further includes: Determine whether the absolute value of the difference between the current temperature and the target set temperature is less than or equal to a second preset threshold within a preset time period; If so, it indicates that the temperature has entered a stable phase.

6. The temperature control method based on duty cycle according to claim 5, characterized in that, The method further includes: When the temperature stabilizes, a different combination of proportional-integral-derivative (PID) parameters is used for temperature control compared to the control phase which involves "regulating the current temperature based on a proportional-integral-derivative (PID) algorithm". In this PID parameter combination, at least one parameter has a value less than the corresponding parameter value in the control phase.

7. The temperature control method based on duty cycle according to claim 6, characterized in that, The temperature control method employs a different combination of proportional-integral-derivative (PID) parameters than the control phase of "regulating the current temperature based on a proportional-integral-derivative (PID) algorithm," including: When the absolute value of the difference between the current temperature and the target set temperature is less than or equal to the second preset threshold, the temperature is controlled by the first proportional-integral-derivative parameter combination. When the absolute value of the difference between the current temperature and the target set temperature is greater than the second preset threshold and less than or equal to the third preset threshold, temperature control is performed using a second proportional-integral-derivative parameter combination, wherein at least one parameter in the second proportional-integral-derivative parameter combination has a value greater than the value of the corresponding parameter in the second proportional-integral-derivative parameter combination.

8. A control device comprising a processor and a storage device, said storage device being adapted to store a plurality of computer programs, characterized in that, The computer program is adapted to be loaded and run by the processor to perform the duty cycle-based temperature control method according to any one of claims 1 to 7.

9. A computer-readable storage medium storing a plurality of computer programs, characterized in that, The computer program is adapted to be loaded and run by a processor to perform the duty cycle-based temperature control method according to any one of claims 1 to 7.

10. A heating device, comprising a temperature sensor and a control device, characterized in that, The temperature sensor is used to detect the current temperature inside the heating device; The control device is used to execute the temperature control method based on duty cycle as described in any one of claims 1 to 7.

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