Low-power continuous heating method based on self-adaptive PPG algorithm and induction cooker

Abstract

The invention belongs to the technical field of induction cookers, and discloses a low-power continuous heating method based on a self-adaptive PPG algorithm and an induction cooker. A power switch tube is driven to work by initializing PPG parameters, collecting characteristic electrical parameters of a main loop of the induction cooker in real time, calculating characteristic error parameters, adaptively optimizing the PPG parameters and adjusting PWM signals according to the optimized PPG parameters. The problems that due to the fact that an intermittent heating mode is adopted in a low-power section of a traditional induction cooker, heating is not uniform, pot temperature fluctuation is large, noise is serious, and a fixed parameter PPG control strategy cannot adapt to nonlinearity and time-varying characteristics of a resonance system of the induction cooker can be effectively solved.

Description

Technical Field

[0001] This application relates to the field of induction cooker technology, and more specifically, to a low-power continuous heating method based on an adaptive PPG algorithm and an induction cooker. Background Technology

[0002] With the upgrading of consumption and the diversification of cooking needs, users have placed higher demands on the precision of induction cooker's heat control, especially its continuous and stable heating capability at low power levels. Traditional induction cookers generally adopt an intermittent heating mode when operating at low power, which leads to uneven heating and large temperature fluctuations in cookware, failing to meet the needs of delicate cooking such as simmering and food preparation. At the same time, the periodic on-off noise generated by intermittent heating seriously affects the user experience and limits the application of induction cookers in high-quality kitchen environments. Therefore, achieving truly low-power continuous silent heating has become a key technological breakthrough for improving the competitiveness of induction cooker products.

[0003] PPG (Pulse-Position-Group) control technology, as the core technology for power regulation in induction cookers, works by precisely controlling the on and off timing of power switching transistors to generate a specific power pulse sequence, thereby achieving precise control of output power. Conventional PPG control technology is primarily based on a preset fixed parameter lookup table method. This method sets a fixed switching frequency at a specific power point and achieves linear power regulation by adjusting the duty cycle of the power pulses. Specifically, the system establishes a correspondence table between power levels and PPG parameters through extensive experimental testing. PPG parameters include key parameters such as the number of working pulses, the number of idle pulses, and the switching frequency. When the user sets the target power, the control system retrieves the corresponding PPG parameters from the table and generates the appropriate power pulse sequence accordingly.

[0004] However, the induction cooker resonant system is a complex, nonlinear, and time-varying system. Its dynamic characteristics are affected by multiple factors, including the electromagnetic characteristics of the cookware, the heat distribution, and component parameter drift. Fixed-parameter PPG control strategies cannot adapt to this complexity, resulting in significant differences in control performance under different cookware and power levels. In the low-power operation range, the "on-off-on" cycle mode of PPG control, due to its fixed parameter combination, cannot adapt to changes in load characteristics caused by variations in cookware material, size, and temperature. This leads to a large deviation between the actual power output and the set value, resulting in low power control accuracy. Furthermore, the periodic on / off operations generate audible audio noise, affecting the user experience, and frequent switching increases switching losses, reducing overall system efficiency.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0006] The purpose of this application is to provide a low-power continuous heating method and an induction cooker based on an adaptive PPG algorithm, which aims to solve the problems of uneven heating, large temperature fluctuations, and high noise caused by intermittent heating in the low-power range of traditional induction cookers, as well as the inability of fixed-parameter PPG control strategies to adapt to complex time-varying systems.

[0007] In a first aspect, this application provides a low-power continuous heating method based on an adaptive PPG algorithm for controlling the heating process of an induction cooker, comprising the following steps: A1. Initialize PPG parameters; the PPG parameters include pulse width, pulse phase, pulse gain, pulse slope, and number of pulses; A2. During the heating process, the characteristic electrical parameters of the main circuit of the induction cooker are collected in real time; the characteristic electrical parameters include bus voltage, resonant current and resonant voltage; A3. Calculate the characteristic error parameters based on the characteristic electrical parameters; the characteristic error parameters include power error, ripple error, and electromagnetic interference prediction error; A4. Adaptively optimize the PPG parameters based on the aforementioned feature error parameters; A5. Adjust the PWM signal according to the optimized PPG parameters to drive the power switching transistor of the induction cooker.

[0008] Preferably, step A1 includes: Based on the desired target power, a preset PPG parameter lookup table is consulted to obtain the preset PPG parameters corresponding to the target power, which are then used to initialize the PPG parameters.

[0009] Preferably, step A3 includes: A301. Calculate intermediate state parameters based on the characteristic electrical parameters; the intermediate state parameters include operating power, phase angle parameters, frequency characteristics, and equivalent impedance; A302. Calculate the characteristic error parameter based on the intermediate state parameter.

[0010] Preferably, step A4 includes: Using the power error as the primary control objective and the ripple error and electromagnetic interference prediction error as secondary control objectives, the PPG parameters are adjusted based on a piecewise optimization strategy.

[0011] Preferably, the step of adjusting the PPG parameters based on a piecewise optimization strategy, with the power error as the primary control objective and the ripple error and the electromagnetic interference prediction error as secondary control objectives, includes: When the power error is greater than a first error threshold, the pulse gain and the number of pulses are adjusted to reduce the power error to below the first error threshold. When the power error is greater than or equal to a second error threshold and less than or equal to a first error threshold, the pulse width and the pulse gain are adjusted to reduce the power error to less than the second error threshold; the second error threshold is less than the first error threshold. When the power error is less than the second error threshold, each PPG parameter is adjusted to maintain the power error less than the second error threshold while optimizing the ripple error and the electromagnetic interference prediction error.

[0012] Preferably, step A5 includes: A501. Based on the pulse width in the optimized PPG parameters, adjust the duration of a single pulse of the PWM signal using a timer; A502. Based on the pulse phase in the optimized PPG parameters, the start time of the PWM signal is adjusted using the timer's prescaler; A503. Adjust the duty cycle of the PWM signal according to the pulse gain in the optimized PPG parameters; A504. Adjust the gate drive resistor of the power switch transistor according to the pulse slope in the optimized PPG parameters; A505. Adjust the pulse group density of the PWM signal according to the number of pulses in the optimized PPG parameters.

[0013] Preferably, the low-power continuous heating method based on the adaptive PPG algorithm further includes the following steps: A6. During the heating process, the junction temperature of the power switch and the temperature of the resonant coil are collected in real time; A7. If the junction temperature of the power switch and the temperature of the resonant coil are both within the corresponding preset normal operating temperature range, then the switching speed of the power switch can be increased within the allowable range of electromagnetic interference. A8. If at least one of the junction temperature of the power switch and the temperature of the resonant coil is within the corresponding preset warning temperature range, then reduce the pulse gain, adjust the number of pulses, and reduce the switching speed of the power switch. A9. If at least one of the power switch junction temperature and the resonant coil temperature is within the corresponding preset over-temperature protection range, then reduce the pulse gain, minimize the number of pulses, and adjust the switching slope to the gentlest switching slope.

[0014] Secondly, this application provides an induction cooker, including a power supply module, a power switch module, an LC resonant circuit, an electrical parameter sampling circuit, and an MCU module. The power switch module is equipped with a power switch transistor, and the LC resonant circuit includes a resonant coil and a resonant capacitor. The electrical parameter sampling circuit is used to collect characteristic electrical parameters of the main circuit of the induction cooker. The characteristic electrical parameters include bus voltage, resonant current, and resonant voltage. The MCU module is used to execute the steps of the low-power continuous heating method based on the adaptive PPG algorithm described above.

[0015] Preferably, the power switch module is further provided with a power device driving circuit, which is used to drive the power switch to turn on and off under the control of the PWM signal output by the MCU module; the power device driving circuit adopts a push-pull driving architecture and can adjust the gate driving resistance of the power switch.

[0016] Preferably, the induction cooker further includes a first temperature sensor for acquiring the junction temperature of the power switch tube and a second temperature sensor for acquiring the temperature of the resonant coil.

[0017] Beneficial Effects: This application provides a low-power continuous heating method and induction cooker based on an adaptive PPG algorithm. By initializing PPG parameters, real-time acquisition of characteristic electrical parameters of the induction cooker's main circuit, calculation of characteristic error parameters, adaptive optimization of PPG parameters, and adjustment of the PWM signal according to the optimized PPG parameters to drive the power switching transistor, this method effectively solves the problems of uneven heating, large temperature fluctuations in cookware, and severe noise caused by the intermittent heating mode in traditional induction cookers at low power. Furthermore, it addresses the inability of fixed-parameter PPG control strategies to adapt to the nonlinear and time-varying characteristics of the induction cooker's resonant system. By real-time acquisition of characteristic electrical parameters such as bus voltage, resonant current, and resonant voltage, and by calculating power error, ripple error, and electromagnetic interference prediction error, this application can dynamically evaluate the operating status of the induction cooker. Based on this, adaptive optimization of PPG parameters such as pulse width, pulse phase, pulse gain, pulse slope, and pulse number enables the control system to make precise adjustments according to actual load and environmental changes, thereby achieving continuous, stable, and quiet heating at low power. Compared with existing technologies, the method of this application significantly improves the heating accuracy, stability and user experience of induction cookers, overcomes the limitations of traditional fixed parameter control, and provides a better solution for the needs of fine cooking. Attached Figure Description

[0018] Figure 1 A flowchart of a low-power continuous heating method based on an adaptive PPG algorithm provided in this application.

[0019] Figure 2 This is a structural schematic diagram of an induction cooker provided in this application.

[0020] Labeling Explanation: 1. Power Supply Module; 2. Power Switch Module; 3. LC Resonant Circuit; 4. Electrical Parameter Sampling Circuit; 5. MCU Module. Detailed Implementation

[0021] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this application, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Please refer to Figure 1 This application discloses a low-power continuous heating method based on an adaptive PPG algorithm in some embodiments, used to control the heating process of an induction cooker, comprising the following steps: A1. Initialize PPG parameters; PPG parameters include pulse width, pulse phase, pulse gain, pulse slope, and number of pulses; A2. During the heating process, the characteristic electrical parameters of the main circuit of the induction cooker are collected in real time; the characteristic electrical parameters include bus voltage, resonant current and resonant voltage; A3. Calculate the characteristic error parameters based on the characteristic electrical parameters; the characteristic error parameters include power error, ripple error, and electromagnetic interference prediction error; A4. Adaptively optimize PPG parameters based on feature error parameters; A5. Adjust the PWM signal according to the optimized PPG parameters to drive the power switching transistor of the induction cooker.

[0024] This application introduces an adaptive PPG algorithm, which can adjust the PPG parameters in real time to cope with the dynamic changes of the induction cooker system, thereby achieving continuous, stable, and quiet heating in the low-power range, significantly improving heating uniformity and user experience, and effectively reducing noise and switching losses.

[0025] Among them, PPG parameters are the core control variables in the Pulse-Position-Group control technology, which include pulse width, pulse phase, pulse gain, pulse slope, and pulse number. These parameters can be recorded in the form of parameter vector θ=[W,φ,G,S,N], where W is the pulse width, φ is the pulse phase, G is the pulse gain, S is the pulse slope, and N is the pulse number.

[0026] Among them, pulse width is used to control the duration of a single power pulse, which directly affects the amount of energy transferred; pulse phase is used to control the starting position of the pulse within the cycle, which affects the resonant state; pulse gain is used to control the amplitude or intensity of the pulse, which is closely related to the output power; pulse slope is used to control the rise / fall time of the pulse, which affects switching losses and electromagnetic compatibility; and pulse number is used to control the number of power pulses sent in a control cycle, which affects the precision of power transmission.

[0027] Among them, characteristic electrical parameters refer to the key electrical quantities in the main circuit of the induction cooker that can reflect the operating status of the system, including bus voltage, resonant current and resonant voltage. These parameters are the basis for subsequent calculations and control.

[0028] Among them, the characteristic error parameters are calculated based on the characteristic electrical parameters and are used to quantify the deviation between the actual operating state and the expected target. These include power error, ripple error and electromagnetic interference (EMI) prediction error, which are the basis for adaptive optimization of PPG parameters.

[0029] In this context, the induction cooker's main circuit refers to the power path that converts mains power into high-frequency electromagnetic energy, ultimately heating the cookware. The bus voltage refers to the voltage on the bus of the main circuit. The resonant current is the current flowing through the LC resonant circuit (which is also equal to the current flowing through the power switching transistor). The resonant voltage is the voltage across the resonant capacitor of the LC resonant circuit.

[0030] The heating method of this application achieves precise control of the heating process of the induction cooker through a series of steps.

[0031] In step A1, when the induction cooker starts up or switches to the target power, the PPG parameters need to be initialized. PPG parameter initialization can be achieved in several ways. For example, a set of default PPG parameters can be preset and loaded directly when the system starts up or switches to the target power. Alternatively, the corresponding PPG parameters can be queried and loaded from a preset parameter table based on the user-defined initial power level. These PPG parameters include pulse width, pulse phase, pulse gain, pulse slope, and pulse count. Pulse width controls the duration of a single pulse, pulse phase controls the pulse position, pulse gain controls the pulse amplitude or intensity, pulse slope controls the pulse rise / fall time, and pulse count controls the number of pulses within a cycle.

[0032] In step A2, during the heating process, it is necessary to collect the characteristic electrical parameters of the induction cooker's main circuit in real time. This collection can be achieved by setting up corresponding sensors and sampling circuits in the induction cooker's main circuit. For example, a voltage sensor can be used to collect the bus voltage, a current sensor to collect the resonant current, and another voltage sensor to collect the resonant voltage. These sensors convert analog signals into electrical signals, which are then converted into digital signals by an analog-to-digital converter (ADC) for processing by the control system.

[0033] In step A3, characteristic error parameters are calculated based on the collected characteristic electrical parameters. The calculation of characteristic error parameters is a crucial step in adaptive control. For example, by combining the collected bus voltage, resonant current, and resonant voltage with preset target values, power error, ripple error, and electromagnetic interference prediction error can be calculated. Power error reflects the deviation between the actual output power and the target power; ripple error reflects the fluctuation of the resonant current or voltage; and electromagnetic interference prediction error reflects the level of electromagnetic interference that may occur during system operation.

[0034] In step A4, the PPG parameters are adaptively optimized based on the calculated characteristic error parameters. This adaptive optimization of the PPG parameters is one of the core innovations of this application. For example, the pulse width, pulse gain, and pulse count can be adjusted according to the magnitude of the power error to make the actual power closer to the target power. When the ripple error is large, the pulse phase can be adjusted to reduce fluctuations in resonant current or voltage. When the electromagnetic interference prediction error is high, the pulse slope can be adjusted to reduce electromagnetic radiation generated by switching transients. This adaptive adjustment mechanism enables the system to dynamically optimize control parameters based on real-time operating conditions, thereby improving control accuracy and system stability.

[0035] In step A5, the PWM signal is adjusted according to the optimized PPG parameters to drive the power switch of the induction cooker. Adjusting the PWM signal is the final step in achieving power control. For example, a corresponding PWM signal can be generated based on the optimized pulse width, pulse phase, pulse gain, pulse slope, and pulse count. These PWM signals are sent to the drive circuit of the power switch to control its on / off state, thereby controlling the heating power of the induction cooker.

[0036] This application presents a low-power continuous heating method based on an adaptive PPG algorithm. This method drives the power switch transistor through PPG parameter initialization, real-time acquisition of characteristic electrical parameters, calculation of characteristic error parameters, adaptive optimization of PPG parameters, and adjustment of the PWM signal, forming a closed-loop control system. When the induction cooker starts or switches to the target power, the PPG parameters are first initialized, providing a foundation for subsequent control. Subsequently, the system monitors characteristic electrical parameters such as the bus voltage, resonant current, and resonant voltage of the induction cooker's main circuit in real time. These parameters are key information reflecting the current operating status of the system. Based on these real-time acquired characteristic electrical parameters, the system calculates characteristic error parameters such as power error, ripple error, and electromagnetic interference prediction error. These error parameters quantify the deviation between the actual operating state and the desired target. For example, a power error occurs when the actual power deviates from the target power; a ripple error occurs when the resonant waveform fluctuates significantly; and an electromagnetic interference prediction error occurs when the system operation may generate high levels of electromagnetic interference.

[0037] Based on these characteristic error parameters, the system adaptively optimizes the PPG parameters. This optimization is dynamic and real-time, adjusting to changes in the induction cooker load (such as cookware material, size, and temperature). For example, if the power error is large, the system adjusts the pulse width, pulse gain, and pulse number to quickly approximate the target power; if the ripple error is large, the system adjusts the pulse phase to smooth the resonant waveform; if the electromagnetic interference prediction error is high, the system adjusts the pulse slope to reduce electromagnetic interference generated by switching transients. Finally, based on the optimized PPG parameters, the system adjusts the PWM signal to precisely drive the power switching transistors of the induction cooker. In this way, this application achieves refined and adaptive control of the induction cooker's heating process, ensuring continuous, stable, and quiet heating even at low power levels, effectively solving the problems of uneven heating, high noise, and low control precision in traditional induction cookers at low power levels.

[0038] The core innovation of this application lies in the introduction of an adaptive PPG algorithm. By acquiring the characteristic electrical parameters of the induction cooker's main circuit in real time and calculating characteristic error parameters based on these parameters, the system can dynamically sense the operating status and load changes of the induction cooker. Based on these error parameters, the PPG parameters (including pulse width, pulse phase, pulse gain, pulse slope, and pulse count) can be adaptively optimized. This adaptive adjustment mechanism enables the system to dynamically adjust the control strategy according to real-time operating conditions, thereby achieving the following advantages: First, it significantly improves the heating uniformity and stability in the low-power range. By optimizing PPG parameters in real time, the system can precisely control the output power, avoiding the temperature fluctuations and uneven heating problems caused by traditional intermittent heating modes, thus meeting the needs of delicate cooking such as simmering over low heat.

[0039] Secondly, it effectively reduces operating noise. Adaptive adjustment enables the system to avoid frequent periodic on / off operations, thereby reducing audible audio noise and improving the user experience.

[0040] Furthermore, it improves power control accuracy and system efficiency. Through real-time feedback and adaptive optimization, the system can more accurately control the actual power near the target power, while optimizing switching losses and improving overall energy efficiency.

[0041] Finally, the robustness and adaptability of the system are enhanced. Regardless of changes in the material, size, or temperature of the cookware, the method of this application can maintain excellent control performance through adaptive adjustment, overcoming the limitations of traditional fixed-parameter methods under complex and variable working conditions.

[0042] In summary, this application, by introducing an adaptive PPG algorithm, achieves intelligent and precise control of the heating process of an induction cooker, effectively solving the pain points of uneven heating at low power, high noise, and low control precision in existing technologies, and bringing significant performance improvements and user experience optimization to induction cooker products.

[0043] Preferably, step A1 may include: Based on the desired target power, the preset PPG parameter lookup table is consulted to obtain the preset PPG parameters corresponding to the target power, which are then used to initialize the PPG parameters.

[0044] Specifically, the desired target power refers to the heating power level that the induction cooker user or system sets and expects the cooker to achieve. For example, it's the power value corresponding to the power setting selected by the user on the cooker's control panel. The preset PPG parameter lookup table can be understood as a data structure stored in the induction cooker's control system memory. It contains the mapping relationship between different target power values ​​and a set of corresponding PPG parameters (including pulse width, pulse phase, pulse gain, pulse slope, and pulse count). This lookup table can be pre-generated through experimental calibration or theoretical calculation before the induction cooker leaves the factory to ensure that the cooker can initially heat with optimal PPG parameters at a specific target power. By consulting this table, preset PPG parameters matching the current desired target power can be quickly obtained, providing a good starting point for subsequent adaptive optimization.

[0045] The proposed solution introduces a target power and a pre-set PPG parameter lookup table during PPG parameter initialization. This allows the system to quickly obtain a set of initial PPG parameters matching the target power based on specific heating requirements. Because the pre-set PPG parameter lookup table stores optimized or calibrated parameter combinations, the induction cooker avoids starting from scratch or using general parameters for trial and error adjustments at the start of the heating process or when switching target power. This significantly shortens the time required to reach a stable heating state and improves the accuracy and efficiency of initial heating. This target power-based initialization method provides a more accurate starting point for the subsequent adaptive PPG algorithm, helping the system converge to its optimal operating state more quickly.

[0046] Through the above technical solution, the heating method of the induction cooker can quickly and accurately obtain a set of preset PPG parameters based on the desired target power during PPG parameter initialization. Compared with a simple general initialization method, this solution significantly improves the system's response speed and heating accuracy during startup, reduces the time and computing resources required for initial PPG parameter adjustment, thereby enhancing the user experience and providing a more stable foundation for subsequent adaptive control, which helps to achieve more efficient and stable low-power continuous heating.

[0047] In some implementations, step A3 includes: A301. Calculate intermediate state parameters based on characteristic electrical parameters; intermediate state parameters include operating power, phase angle parameters, frequency characteristics, and equivalent impedance; A302. Calculate the characteristic error parameters based on the intermediate state parameters.

[0048] Intermediate state parameters refer to a series of intermediate calculation results introduced during the calculation process from the initially acquired characteristic electrical parameters to the final characteristic error parameters. These intermediate state parameters, such as operating power, phase angle parameters, frequency characteristics, and equivalent impedance, can reflect the operating state of the induction cooker's main circuit in more detail. Operating power usually refers to the actual output power of the induction cooker; phase angle parameters can characterize the resonant state of the resonant circuit or the load characteristics; frequency characteristics can reflect the operating frequency or stability of the resonant circuit; and equivalent impedance can reflect the degree of matching between the load and the resonant circuit. By introducing these intermediate state parameters, the complex error calculation process can be decomposed into stages that are easier to manage and analyze.

[0049] Characteristic error parameters, such as power error, ripple error, and electromagnetic interference (EMI) prediction error, are key indicators for evaluating the heating performance and operational stability of induction cookers. Power error measures the deviation between the actual operating power and the desired target power; ripple error reflects the smoothness of the output power or the stability of the resonant state; and EMI prediction error is used to assess potential electromagnetic compatibility issues. Accurate calculation of these error parameters is fundamental to achieving adaptive PPG parameter optimization.

[0050] The above technical solution modularizes and hierarchically processes the calculation of characteristic error parameters. This decomposed calculation method not only improves the accuracy and reliability of the calculation but also enhances the maintainability and debuggability of the system. Specifically, by calculating intermediate state parameters first, a deeper understanding of the induction cooker's operating state can be achieved. For example, it can clearly identify whether the problem stems from inaccurate power output, unstable resonance, or potential electromagnetic interference. This detailed analysis of intermediate state parameters helps to more accurately pinpoint the problem and provides more targeted guidance for subsequent PPG parameter optimization. Furthermore, this step-by-step calculation structure makes the algorithm implementation clearer, facilitating independent verification and optimization of each calculation stage, thereby improving the performance and stability of the entire heating control system.

[0051] In some possible implementations, step A301 includes: Calculate the operating power based on the resonant current and bus voltage or resonant voltage in the characteristic electrical parameters; The phase angle parameter is determined based on the zero-crossing or peak position of the resonant current and resonant voltage waveforms in the characteristic electrical parameters. Analyze the period of the resonant current or resonant voltage in the characteristic electrical parameters, and calculate the frequency characteristics based on the period; The effective impedance is obtained by calculating the ratio of the effective values ​​of the resonant voltage and resonant current in the characteristic electrical parameters.

[0052] Specifically, the operating power is calculated by comprehensively analyzing real-time acquired characteristic electrical parameters, namely the resonant current and the bus voltage or resonant voltage. For example, it can be calculated by multiplying the instantaneous values ​​of the resonant current and the bus voltage and taking the average, or by using the effective values ​​of the resonant current and the resonant voltage and the phase angle. The purpose is to provide accurate input for subsequent power error calculations.

[0053] The phase angle parameter is determined based on the waveform characteristics of the resonant current and resonant voltage. Specifically, the phase difference between these two waveforms can be calculated by detecting their zero-crossing or peak positions. For example, the time differences between the zero-crossing moments of the resonant current waveform (from negative to positive) and the resonant voltage waveform (from negative to positive) can be recorded and used to calculate the phase angle. The purpose is to accurately characterize the operating state of the LC resonant circuit and provide a basis for calculating ripple error.

[0054] In practical applications, frequency characteristics are calculated by analyzing the period of the resonant current or resonant voltage in the characteristic electrical parameters. For example, the period can be determined by measuring the time interval between two consecutive zero-crossing points of the resonant current or resonant voltage, and then the current resonant frequency can be calculated as the frequency characteristic. The purpose is to monitor the operating frequency of the induction cooker in real time to assess whether it is within the preset safe frequency range, thereby predicting electromagnetic interference.

[0055] Furthermore, the equivalent impedance is obtained by calculating the effective value ratio between the resonant voltage and resonant current in the characteristic electrical parameters. Specifically, the effective values ​​of the resonant voltage and resonant current can be calculated separately (the calculation methods for the effective values ​​of voltage and current are existing technologies and will not be detailed here). Then, the effective value of the resonant voltage is divided by the effective value of the resonant current to obtain the equivalent impedance of the current LC resonant circuit. Its purpose is to reflect the matching degree between the load characteristics and the resonant circuit, providing an important reference for calculating electromagnetic interference prediction errors.

[0056] Through the above technical solution, this application ensures high accuracy and reliability in the calculation process of intermediate state parameters. Specifically, by clearly defining the calculation methods for operating power, phase angle parameters, frequency characteristics, and equivalent impedance, control deviations caused by fuzzy or inaccurate calculations are avoided, thereby improving the control accuracy and stability of the entire low-power continuous heating method. This explicit calculation method enables the system to more accurately perceive the operating status of the induction cooker, providing solid data support for subsequent error analysis and adaptive optimization of PPG parameters, thus improving the performance of the induction cooker and the user experience in low-power heating mode.

[0057] In some possible implementations, step A302 includes: The power error is obtained by calculating the difference between the working power and the expected target power. The ripple error is obtained by calculating the difference between the phase angle parameter and the preset target resonant phase angle. The electromagnetic interference prediction error is calculated based on the degree to which the frequency characteristics exceed the preset frequency safety range and / or the degree to which the equivalent impedance exceeds the preset impedance safety range.

[0058] Power error refers to the deviation between the actual operating power and the system's expected target power. By calculating the difference between the real-time calculated operating power and the preset expected target power, the power difference between the current heating state and the target heating state can be quantified. This difference calculation directly reflects the accuracy of the system's power output, providing a core basis for subsequent PPG parameter optimization.

[0059] Furthermore, ripple error refers to the deviation between the actual phase angle parameter and the preset target resonant phase angle. During the heating process of an induction cooker, the resonant phase angle is a crucial indicator reflecting the operating state of the resonant circuit; its ideal value typically corresponds to the optimal resonant state. By calculating the difference between the real-time detected phase angle parameter and the preset target resonant phase angle, the degree of deviation of the resonant circuit can be assessed, thereby indirectly reflecting the energy conversion efficiency and stability during the heating process. This ripple error calculation helps identify and correct resonant offset problems that may lead to uneven heating or decreased efficiency.

[0060] Furthermore, the calculation of electromagnetic interference (EMI) prediction error is based on the degree to which frequency characteristics and / or equivalent impedance exceed a preset safety range. Specifically, when the frequency characteristics of the resonant current or resonant voltage exceed a preset frequency safety range, or when the equivalent impedance exceeds a preset impedance safety range, it may indicate a potential EMI risk or operational anomaly in the system. By quantifying these exceedances, the potential EMI level of the system can be predicted. For example, abnormal frequency characteristics may lead to radiated interference, while drastic changes in equivalent impedance may affect the operating state of power switches, thereby generating conducted interference. This error calculation aims to identify and mitigate risks that may affect system stability and compliance with electromagnetic compatibility standards in advance.

[0061] Specifically, firstly, the degree to which the frequency characteristics exceed the preset frequency safety range needs to be quantified into a specific numerical value (hereinafter referred to as the frequency deviation index). For example, it can be expressed as the absolute difference or relative percentage deviation between the frequency characteristics and the preset frequency safety range boundary. Similarly, the degree to which the equivalent impedance exceeds the preset impedance safety range also needs to be quantified into a corresponding numerical value (hereinafter referred to as the impedance deviation index). For example, it can be the absolute difference or relative percentage deviation between the actual impedance and the preset impedance safety range boundary. Once these degrees of excess are quantified, those skilled in the art can use a pre-established mathematical model or empirical relationship reflecting the influence of frequency and impedance characteristic changes on electromagnetic interference to calculate the electromagnetic interference prediction error. This model or relationship can be derived from theoretical analysis, simulation results, or experimental data. It takes the quantified frequency excess and / or impedance excess as input, and outputs the corresponding electromagnetic interference prediction error through a specific function mapping. For example, the function can be: the electromagnetic interference prediction error is equal to the weighted sum of the frequency deviation index and the impedance deviation influence.

[0062] This application's solution, through precise difference calculations and exceedance assessments of intermediate state parameters such as operating power, phase angle parameters, frequency characteristics, and equivalent impedance, can comprehensively and accurately quantify power deviations, resonance state deviations, and potential electromagnetic interference risks during the induction cooker's heating process. The calculation of these characteristic error parameters provides multi-dimensional feedback information for subsequent adaptive optimization of PPG parameters. For example, power error directly guides power output adjustment, ripple error guides resonance state correction, and electromagnetic interference prediction error is used to prevent and suppress electromagnetic compatibility issues. Therefore, the system can achieve refined control and optimization of the induction cooker's heating process based on this detailed error information.

[0063] The above technical solutions enable quantitative evaluation of key performance indicators during the heating process of induction cookers, providing more comprehensive and accurate feedback signals for the adaptive PPG algorithm. Specifically, calculating power error ensures the accuracy of heating power, avoiding overshoot or undershoot in power output; calculating ripple error effectively monitors and maintains the stable operation of the resonant circuit, improving energy conversion efficiency and reducing unnecessary losses; and calculating electromagnetic interference prediction error allows for the early identification and avoidance of potential electromagnetic compatibility issues, ensuring stable equipment operation and compliance with relevant standards. These refined error calculation methods significantly improve the response speed, control accuracy, and robustness of the entire heating control system, enabling the induction cooker to achieve more stable, efficient, and electromagnetically compatible operation in low-power continuous heating mode.

[0064] In some preferred embodiments, step A4 includes: With power error as the primary control objective and ripple error and electromagnetic interference prediction error as secondary control objectives, the PPG parameters are adjusted based on a piecewise optimization strategy.

[0065] Specifically, setting power error as the primary control objective means prioritizing minimizing the deviation between the actual operating power and the desired target power during the PPG parameter optimization process. Power error directly reflects the heating effect of the induction cooker and the user's set heating requirements, and is a core indicator for measuring the performance of the heating system. Therefore, it is given the highest priority in the optimization strategy to ensure the accuracy and stability of heating.

[0066] Setting ripple error and electromagnetic interference (EMI) prediction error as secondary control objectives can be understood as further optimizing these two errors while meeting the primary control objective (i.e., minimizing power error). Ripple error is typically related to the operating state of the resonant circuit, energy conversion efficiency, and heating uniformity; excessive ripple error can lead to heating instability or decreased efficiency. EMI prediction error is used to assess the potential electromagnetic radiation level generated by the system; excessive EMI may affect the normal operation of other electronic devices or fail to meet electromagnetic compatibility standards. By setting these as secondary objectives, the overall performance and reliability of the system can be improved while ensuring the core heating function.

[0067] In practical applications, adjusting PPG parameters based on a segmented optimization strategy involves dividing the entire optimization process into different stages according to the magnitude of the current power error, and employing different optimization focuses and adjustment strategies at each stage. For example, when the power error is large, a more aggressive adjustment approach may be needed to quickly reduce the power error; while when the power error is small, a more refined adjustment approach may be needed to further optimize ripple error and electromagnetic interference prediction error while keeping the power error within an acceptable range. This segmented strategy makes the optimization process more flexible and efficient, adapting to different operating conditions and error levels.

[0068] This application's solution addresses the conflicts and efficiency issues that may arise in multi-objective control using traditional single-objective or non-priority optimization strategies by setting power error as the primary control objective and supplementing it with ripple error and electromagnetic interference prediction error as secondary control objectives. Because power error is prioritized, the system can respond quickly and accurately to the user-defined heating demand, ensuring precise heating power output. Simultaneously, the introduction of secondary objectives allows the system to balance heating stability (through ripple error optimization) and electromagnetic compatibility (through electromagnetic interference prediction error optimization) while meeting the primary power requirement. Furthermore, the use of a piecewise optimization strategy means that the adjustment of PPG parameters is no longer linear and singular, but dynamically adjusts the optimization focus and intensity based on the error magnitude. When the error is large, the system can converge quickly; when the error is small, fine-tuning can be performed, thus avoiding over-adjustment or oscillation and improving the robustness and stability of the control.

[0069] Through the above technical solution, this application enables more precise and efficient control of the heating process of an induction cooker. Compared with optimization methods that do not distinguish between primary and secondary objectives, this solution can significantly improve the control accuracy and response speed of heating power, ensuring that the induction cooker can more accurately reach and maintain the target heating power. Simultaneously, while ensuring power accuracy, the system can effectively suppress resonant ripple, improve heating stability and efficiency, and reduce potential electromagnetic interference, thereby enhancing the overall performance of the induction cooker and the user experience. This segmented, multi-objective optimization strategy allows the system to adopt the most appropriate adjustment method when facing errors of different magnitudes, thus improving the adaptability and robustness of the control system.

[0070] Specifically, with power error as the primary control objective and ripple error and electromagnetic interference prediction error as secondary control objectives, the steps for adjusting PPG parameters based on a piecewise optimization strategy can include: When the power error is greater than the first error threshold, adjust the pulse gain and pulse number to reduce the power error to below the first error threshold. When the power error is greater than or equal to the second error threshold and less than or equal to the first error threshold, the pulse width and pulse gain are adjusted to reduce the power error to less than the second error threshold; the second error threshold is less than the first error threshold. When the power error is less than the second error threshold, adjust each PPG parameter to keep the power error less than the second error threshold while optimizing the ripple error and electromagnetic interference prediction error.

[0071] Specifically, the first and second error thresholds are preset boundary values ​​used to divide the power error range. The second error threshold is set to be less than the first error threshold to form a graded control interval. For example, the first error threshold can be set to 20% of the target power, and the second error threshold can be set to 5% of the target power. Different PPG parameter adjustment strategies are adopted when the power error is in different intervals. When the power error is large, i.e., greater than the first error threshold, the system mainly reduces the power error quickly by adjusting the pulse gain and the number of pulses. The pulse gain directly affects the amplitude or intensity of the pulse, while the number of pulses controls the number of pulses in the period. Both have a significant and direct impact on the output power, making them suitable for quickly and significantly correcting the power. When the power error is in a medium range, i.e., greater than or equal to the second error threshold and less than or equal to the first error threshold, the system adjusts the pulse width and pulse gain. The pulse width controls the duration of a single pulse, providing relatively fine-grained power adjustment. Combined with the adjustment of the pulse gain, it can ensure the convergence speed while avoiding over-adjustment, allowing the power error to smoothly enter a smaller error range. When the power error is very small, i.e., less than the second error threshold, the power is close to the target value, and the system will perform fine-tuning. At this stage, in addition to keeping the power error within a small range, ripple error and electromagnetic interference prediction error will also be optimized simultaneously. This means that the system will comprehensively consider all PPG parameters, such as pulse width, pulse phase, pulse gain, pulse slope, and pulse number, and make coordinated adjustments to further improve heating stability and electromagnetic compatibility while meeting power accuracy requirements.

[0072] This application's solution divides the power error into different intervals and employs different PPG parameter adjustment strategies for each interval, thereby solving the problems of response hysteresis, overshoot, or convergence difficulties that may exist in traditional single control strategies when facing power errors of varying magnitudes. When the power error is large, the system prioritizes rapid and large-amplitude adjustments to pulse gain and pulse number, which have a significant impact on power, to quickly bring the power back to the target range and avoid prolonged deviation from the target power. As the power error decreases and enters the medium error range, the system switches to a combination of pulse width and pulse gain adjustments. This approach provides more precise power regulation capabilities, helping to smoothly approach the target power and reduce oscillations. Finally, when the power error is within a very small range, the system expands its control focus from simple power correction to comprehensive optimization of ripple error and electromagnetic interference prediction error. Through coordinated adjustment of all PPG parameters, the system further improves the stability and electromagnetic compatibility of the heating process while ensuring power accuracy. This segmented control logic enables the system to maintain efficient, stable, and precise control performance throughout the entire heating process.

[0073] Through the above technical solution, this application achieves more efficient, stable, and precise control over the low-power continuous heating process of an induction cooker. This segmented optimization strategy effectively avoids slow convergence due to overly fine adjustment when the power error is large, and oscillations or insufficient precision caused by coarse adjustment when the power error is small. Specifically, by selectively adjusting the PPG parameters within different error ranges, the system can achieve the optimal balance between rapid response and fine control according to actual needs. This not only significantly improves the convergence speed and control accuracy of the power error, but also optimizes ripple error and electromagnetic interference prediction error when the power is close to the target value, thereby comprehensively improving the heating performance, user experience, and electromagnetic compatibility of the induction cooker, effectively solving the problems of insufficient control accuracy and stability in low-power continuous heating scenarios caused by traditional control methods.

[0074] In some preferred embodiments, a specific example is given below. Assume that the target power of the induction cooker is 1000W, the first error threshold is set to 20% of the target power (i.e., 200W), and the second error threshold is set to 5% of the target power (i.e., 50W).

[0075] When the induction cooker starts or the load changes significantly, if the real-time measured operating power is 600W, the power error is 400W. At this time, the power error (400W) is greater than the first error threshold (200W). According to the solution of this application, the system will prioritize adjusting the pulse gain and the number of pulses. For example, by increasing the pulse gain and / or increasing the number of pulses (e.g., gradually increasing with relatively large step sizes), the output power will be rapidly increased so that it quickly approaches the target power.

[0076] As adjustments proceed, assuming the operating power increases to 900W, the power error is 100W. This error value is greater than or equal to the second error threshold (50W) and less than or equal to the first error threshold (200W). During this phase, the system adjusts the pulse width and pulse gain, for example, by fine-tuning the pulse width and pulse gain (e.g., by gradually fine-tuning in relatively small steps), to smoothly converge the power towards the target power and avoid overshoot.

[0077] Ultimately, when the operating power reaches 980W and the power error is 20W, the power error (20W) is less than the second error threshold (50W). In this fine-tuning stage, the system comprehensively adjusts all PPG parameters, including pulse width, pulse phase, pulse gain, pulse slope, and pulse count. While maintaining the power error below 50W, it further optimizes the resonant phase angle to reduce ripple error and adjusts the frequency characteristics and equivalent impedance to reduce electromagnetic interference prediction error, thereby achieving stable, efficient, and low-interference continuous heating.

[0078] Preferably, step A5 may include: A501. Based on the pulse width in the optimized PPG parameters, adjust the duration of a single pulse of the PWM signal using a timer; A502. Based on the pulse phase in the optimized PPG parameters, the start time of the PWM signal is adjusted using the timer's prescaler; A503. Adjust the duty cycle of the PWM signal according to the pulse gain in the optimized PPG parameters; A504. Adjust the gate drive resistor of the power switch transistor according to the pulse slope in the optimized PPG parameters; A505. Adjust the pulse group density of the PWM signal according to the number of pulses in the optimized PPG parameters.

[0079] Specifically, pulse width controls the duration of a single PWM pulse. By adjusting the timer, the conduction time of each pulse can be precisely controlled, thus affecting the energy delivered to the load. Pulse phase controls the starting position of the PWM signal within a cycle. By adjusting the start time of the PWM signal using the timer's prescaler, precise control of the pulse position can be achieved, which is crucial for optimizing resonant circuits and suppressing electromagnetic interference. Pulse gain is typically related to the duty cycle of the PWM signal. By adjusting the duty cycle, the effective voltage or current of the PWM signal can be changed, thereby controlling the conduction level and output power of the power switch. Pulse slope refers to the steepness of the rising and falling edges of the PWM pulse. By adjusting the gate drive resistor of the power switch, the switching speed of the power switch can be controlled, thus affecting switching losses and electromagnetic compatibility. Pulse count controls the number or density of PWM pulses within a cycle. By adjusting the pulse group density of the PWM signal, fine-grained control of the output power can be achieved, especially in low-power continuous heating scenarios, helping to maintain stable heating performance.

[0080] This application's solution achieves precise control of the power switching transistor in an induction cooker by precisely adjusting the optimized PPG parameters (including pulse width, pulse phase, pulse gain, pulse slope, and pulse count) one-to-one with various adjustable parameters of the PWM signal (pulse width, start time, duty cycle, gate drive resistance, and pulse group density). For example, adjusting the pulse width and pulse gain directly affects the energy transferred to the load, thereby controlling the heating power; adjusting the pulse phase helps optimize the resonant state and reduce reactive power loss; adjusting the pulse slope balances switching losses and electromagnetic interference; and adjusting the pulse count provides a more flexible control method for continuous heating at low power. Therefore, the optimization result of each PPG parameter can be effectively converted into a specific PWM signal adjustment strategy, ensuring that the power switching transistor operates in its optimal state.

[0081] Through the aforementioned hardware and software coordinated adjustment technology, more precise and comprehensive control of the PWM signal can be achieved. Specifically, by adjusting the pulse width, pulse phase, pulse gain, pulse slope, and pulse count, the output of the PWM signal can be more accurately matched to the actual heating needs and operating status of the induction cooker. This not only helps improve heating efficiency and stability but also effectively reduces switching losses, optimizes electromagnetic compatibility, and provides a smoother and more precise power output for low-power continuous heating, thereby enhancing the overall performance of the induction cooker and the user experience.

[0082] Furthermore, this low-power continuous heating method based on the adaptive PPG algorithm may also include the following steps: A6. During the heating process, the junction temperature of the power switch and the temperature of the resonant coil are collected in real time; A7. If the junction temperature of the power switch and the temperature of the resonant coil are both within the corresponding preset normal operating temperature range, then the switching speed of the power switch can be increased within the allowable range of electromagnetic interference. A8. If at least one of the junction temperature of the power switch and the temperature of the resonant coil is within the corresponding preset warning temperature range, then reduce the pulse gain, adjust the number of pulses, and reduce the switching speed of the power switch. A9. If at least one of the power switch junction temperature and the resonant coil temperature is within the corresponding preset over-temperature protection range, then reduce the pulse gain, minimize the number of pulses, and adjust the switching slope to the gentlest switching slope.

[0083] Specifically, in step A6, the junction temperature of the power switch refers to the temperature of the semiconductor chip inside the power switch, and the temperature of the resonant coil refers to the temperature of the resonant coil in the LC resonant circuit. These temperature parameters are key indicators reflecting the internal thermal state of the induction cooker. They can be acquired by temperature sensors placed near the power switch and near the resonant coil, and are read and processed in real time by the MCU module.

[0084] Steps A7, A8, and A9 define a refined control strategy based on temperature conditions. The preset normal operating temperature range, preset warning temperature range, and preset over-temperature protection range are temperature ranges pre-set based on the material characteristics, rated parameters, and safety margins of the power switch and resonant coil. For example, the normal operating temperature range can be set as the ideal temperature range for long-term stable operation of the device; the warning temperature range indicates that the temperature is approaching the safety upper limit and intervention measures are required; the over-temperature protection range indicates that the temperature has reached or exceeded the safety limit and strong protective measures must be taken immediately.

[0085] In practical applications, increasing the switching speed of power transistors usually means shortening the switching time, which helps reduce switching losses and thus improve efficiency. However, excessively fast switching speeds can increase electromagnetic interference (EMI), so it's necessary to operate within the allowable EMI range (e.g., gradually increasing the switching speed while monitoring EMI, such as EMI prediction errors, until the EMI approaches the boundary of the allowable range). Reducing the pulse gain directly reduces the power input to the load, thereby reducing heat generation. Adjusting the number of pulses can change the energy transfer density per unit time; reducing the number of pulses also reduces average power and heat generation. Reducing the switching speed of power transistors increases switching losses but effectively reduces EMI and, in some cases, aids in heat dissipation. Adjusting the switching slope to the gentlest possible switching slope means extending the switching time, which significantly increases switching losses but maximally suppresses EMI and serves as an emergency cooling and protection measure in extreme over-temperature conditions.

[0086] This application's solution addresses the lack of thermal state sensing and control for key components in the basic solution by introducing real-time monitoring of the power switch junction temperature and resonant coil temperature. Because induction cookers generate significant heat during prolonged or high-power operation, core components such as the power switch and resonant coil can become overheated if this heat cannot be dissipated promptly, affecting their performance and lifespan. By acquiring this temperature information in real-time through step A6, the system can accurately grasp the internal heat load of the induction cooker.

[0087] Based on this, steps A7, A8, and A9 employ differentiated control strategies according to different temperature ranges. When the temperature is within the preset normal operating temperature range (step A7), the system can moderately increase the switching speed of the power switch within the allowable range of electromagnetic interference to optimize switching losses and improve overall efficiency. This is a strategy that pursues performance optimization within a safe range. When the temperature enters the preset warning temperature range (step A8), it indicates that the component temperature is approaching the danger threshold. At this time, the system will actively reduce the pulse gain, adjust the number of pulses, and reduce the switching speed of the power switch (for example, by adjusting these parameters step by step according to a preset sequence and corresponding preset step size until the temperature returns to the preset normal operating temperature range). These measures aim to reduce the output power and heat generation of the induction cooker, while reducing electromagnetic interference by reducing the switching speed, thereby providing buffer and cooling time for the components and preventing further deterioration. When the temperature reaches the preset over-temperature protection range (step A9), the system will take more aggressive protection measures, including further reducing the pulse gain, minimizing the number of pulses, and adjusting the switching slope to the gentlest switching slope. These measures minimize power output and heat generation, and suppress electromagnetic interference to the greatest extent possible, thereby protecting power switching transistors and resonant coils from permanent damage in extreme cases.

[0088] Through the above technical solution, this application effectively solves the problem of component overheating caused by the lack of temperature monitoring and control in traditional heating methods. This solution, by sensing the junction temperature of the power switch transistor and the temperature of the resonant coil in real time, and adaptively adjusting the heating parameters according to the temperature conditions, significantly improves the safety, reliability, and component lifespan of the induction cooker. Compared to basic solutions based solely on electrical parameter optimization, the additional technical features of this application enable the induction cooker to operate stably under a wider range of working conditions, effectively avoiding malfunctions caused by excessive thermal stress, thereby enhancing the user experience and the overall competitiveness of the product.

[0089] refer to Figure 2 This application provides an induction cooker, including a power supply module 1, a power switch module 2, an LC resonant circuit 3, an electrical parameter sampling circuit 4, and an MCU module 5. The power switch module 2 is equipped with a power switch transistor, and the LC resonant circuit 3 includes a resonant coil and a resonant capacitor. The electrical parameter sampling circuit 4 is used to collect characteristic electrical parameters of the main circuit of the induction cooker. The characteristic electrical parameters include bus voltage, resonant current, and resonant voltage. MCU module 5 is used to execute the steps of the low-power continuous heating method based on the adaptive PPG algorithm described above.

[0090] Specifically, power module 1 provides a stable energy supply for the entire system; power switch module 2, under the control of MCU module 5, drives LC resonant circuit 3 through power switching transistors to adjust the heating power; electrical parameter sampling circuit 4 monitors the operating status of the induction cooker's main circuit in real time and feeds back key characteristic electrical parameters to MCU module 5; MCU module 5, as the core controller, executes an adaptive PPG algorithm based on the collected characteristic electrical parameters, optimizes the PPG parameters, and generates corresponding PWM signals to precisely control the operation of the power switching transistors. Through this close integration of hardware and software, the induction cooker of this application can overcome the problems of uneven heating, high noise, and low control precision in traditional induction cookers at low power levels, achieving continuous, stable, and quiet heating.

[0091] Specifically, the power module 1 of the induction cooker is responsible for converting external AC power into DC power suitable for the operation of the internal circuitry. For example, the power module 1 can be implemented using a simple rectifier and filter circuit, or a switching power supply module can be used to provide a more stable voltage output.

[0092] Power switch module 2 is the core component for power regulation, and it is equipped with a power switching transistor. The power switching transistor can be an insulated-gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET), etc. The power switching transistor can be driven by a simple resistor current limiting method, or controlled by a dedicated driver chip.

[0093] The LC resonant circuit 3 is crucial for the induction heating function of an induction cooker. It consists of a resonant coil and a resonant capacitor. The resonant coil, typically made of copper wire, generates an alternating magnetic field to inductively heat the cookware. The resonant capacitor and the resonant coil together form a resonant circuit, determining the system's resonant frequency. The winding method and material selection of the resonant coil can be designed based on cost and basic performance requirements; for example, a single-layer or multi-layer winding can be used. The type and capacitance of the resonant capacitor can also be selected according to design needs; for example, a polypropylene film capacitor or a ceramic capacitor can be used.

[0094] The electrical parameter sampling circuit 4 is used to acquire characteristic electrical parameters of the induction cooker's main circuit in real time, including bus voltage, resonant current, and resonant voltage. Bus voltage sampling can be achieved through a voltage divider resistor network; resonant current sampling can be achieved through a current transformer or a Hall sensor; and resonant voltage sampling can be achieved through a voltage divider resistor network or an isolation sampling circuit. These sampling circuits can convert analog electrical signals into digital signals for processing by the MCU module 5. For example, a simple sample-and-hold circuit and an analog-to-digital converter can be used for data acquisition.

[0095] MCU module 5 is the control core of the induction cooker, used to execute the steps of the low-power continuous heating method based on the adaptive PPG algorithm described above. MCU module 5 can be a commonly available microcontroller, such as one based on the ARM Cortex-M series core, which integrates a central processing unit, memory, timers, analog-to-digital converters, and general-purpose input / output interfaces.

[0096] Preferably, the power switch module 2 is further provided with a power device driving circuit, which is used to drive the power switch to turn on and off under the control of the PWM signal output by the MCU module 5; the power device driving circuit adopts a push-pull driving architecture and can adjust the gate driving resistance of the power switch.

[0097] Specifically, the power device drive circuit can be understood as an interface circuit located between the MCU module 5 and the power switching transistor. Its main function is to convert the low-power PWM signal generated by the MCU module 5 into a high-power drive signal sufficient to drive the power switching transistor to switch on and off quickly and reliably. Its purpose is to ensure that the power switching transistor can switch according to the expected timing and state, thereby achieving precise control of the induction cooker's heating process.

[0098] The push-pull drive architecture refers to a power device drive circuit that uses a pair of complementary switching devices (such as NPN / PNP transistors or N-channel / P-channel MOSFETs) to drive the gate of the power switch. When one device is turned on, the other is turned off, thereby achieving rapid charging and discharging of the gate capacitance. Its purpose is to provide high-efficiency, high-speed drive capability, effectively reduce the switching losses of the power switch, and improve its operational reliability.

[0099] In practical applications, adjusting the gate drive resistor of a power switch refers to the ability of the power device drive circuit to change the resistance value connected between the output of the drive circuit and the gate of the power switch according to control requirements. This can be achieved, for example, by using a variable resistor, a digital potentiometer, or by switching between fixed resistors of different values. The purpose is to precisely control the switching speed (i.e., rise time and fall time) of the power switch, thereby affecting switching losses, electromagnetic interference (EMI) generation, and the junction temperature of the power switch.

[0100] This application's solution, by introducing a power device drive circuit and adopting a push-pull drive architecture, provides a strong and efficient drive signal to the power switch, ensuring that the power switch can respond quickly and accurately when receiving the PWM signal from the MCU module. The fast charging and discharging capability of the push-pull drive architecture effectively reduces the power switch's losses during the switching process, improving overall efficiency. Furthermore, by adjusting the gate drive resistor of the power switch, the switching speed of the power switch can be flexibly adjusted according to actual operating conditions and optimization goals. For example, when it is necessary to reduce electromagnetic interference or control the junction temperature of the power switch, the gate drive resistor can be appropriately increased to slow down the switching speed; while when pursuing higher efficiency or faster response, the gate drive resistor can be decreased to speed up the switching speed. This adjustability allows the switching characteristics of the power switch to be better matched with parameters such as the pulse slope optimized by the adaptive PPG algorithm, thereby achieving more precise and stable heating control.

[0101] Furthermore, the induction cooker may also include a first temperature sensor for acquiring the junction temperature of the power switch tube and a second temperature sensor for acquiring the temperature of the resonant coil.

[0102] The first and second temperature sensors can be thermistors, thermocouples, infrared sensors, or integrated temperature sensors.

[0103] By introducing a first temperature sensor and a second temperature sensor, real-time temperature monitoring of the key heating components of the induction cooker—the power switching transistor and the resonant coil—is achieved. This temperature data can be acquired and processed by the MCU module 5. Based on this real-time temperature feedback, the MCU module 5 can dynamically adjust the PPG parameters during the heating process or take other protective measures according to preset temperature thresholds and control strategies. Therefore, the system can promptly detect and respond to overheating situations, effectively avoiding equipment damage or safety hazards caused by excessively high temperatures, thereby significantly improving the stability and reliability of the induction cooker's operation.

[0104] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A low-power continuous heating method based on an adaptive PPG algorithm for controlling a heating process of an electromagnetic oven, characterized in that, The method comprises the following steps: A1. initializing PPG parameters; the PPG parameters include pulse width, pulse phase, pulse gain, pulse slope and pulse number; A2. acquiring characteristic electrical parameters of the main loop of the induction cooker in real time during the heating process; the characteristic electrical parameters include bus voltage, resonance current and resonance voltage; A3. calculating characteristic error parameters according to the characteristic electrical parameters; the characteristic error parameters include power error, ripple error and electromagnetic interference estimation error; A4. adaptively optimizing the PPG parameters according to the characteristic error parameters; A5. adjusting the PWM signal according to the optimized PPG parameters, so as to drive the power switch tube of the induction cooker to work.

2. The low power continuous heating method based on adaptive PPG algorithm according to claim 1, characterized in that, Step A1 comprises: querying a preset PPG parameter query table according to the expected target power to obtain preset PPG parameters corresponding to the target power, for initializing the PPG parameters.

3. The low power continuous heating method based on adaptive PPG algorithm according to claim 1, characterized in that, Step A3 comprises: A301. calculating intermediate state parameters according to the characteristic electrical parameters; the intermediate state parameters include working power, phase angle parameter, frequency characteristic and equivalent impedance; A302. calculating the characteristic error parameters according to the intermediate state parameters.

4. The low power continuous heating method based on adaptive PPG algorithm of claim 1, wherein, Step A4 comprises: taking the power error as the main control target, taking the ripple error and the electromagnetic interference estimation error as the secondary control targets, and adjusting the PPG parameters based on a segmented optimization strategy.

5. The low power continuous heating method based on adaptive PPG algorithm according to claim 4, characterized in that, The step of taking the power error as the main control target, taking the ripple error and the electromagnetic interference estimation error as the secondary control targets, and adjusting the PPG parameters based on a segmented optimization strategy comprises: when the power error is greater than a first error threshold, adjusting the pulse gain and the pulse number to make the power error below the first error threshold; when the power error is greater than or equal to a second error threshold and less than or equal to the first error threshold, adjusting the pulse width and the pulse gain to make the power error less than the second error threshold; the second error threshold is less than the first error threshold; when the power error is less than the second error threshold, adjusting the PPG parameters to keep the power error less than the second error threshold while optimizing the ripple error and the electromagnetic interference estimation error.

6. The low power continuous heating method based on adaptive PPG algorithm according to claim 1, characterized in that, Step A5 comprises: A501. adjusting the duration of a single pulse of the PWM signal according to the pulse width in the optimized PPG parameters by using a timer; A502. adjusting the starting time of the PWM signal according to the pulse phase in the optimized PPG parameters by using a prescaler of the timer; A503. adjusting the duty cycle of the PWM signal according to the pulse gain in the optimized PPG parameters; A504. adjusting the gate drive resistance of the power switch tube according to the pulse slope in the optimized PPG parameters; A505. adjusting the pulse group density of the PWM signal according to the pulse number in the optimized PPG parameters.

7. The low power continuous heating method based on adaptive PPG algorithm according to claim 1, characterized in that, Further comprising the step: A6. acquiring the junction temperature of the power switch tube and the temperature of the resonance coil in real time during the heating process; A7. If both the power switch tube junction temperature and the resonant coil temperature are within the corresponding preset normal working temperature range, then the switching speed of the power switch tube is increased within the electromagnetic interference allowable range; A8. If at least one of the power switch tube junction temperature and the resonant coil temperature is within the corresponding preset pre-warning temperature range, then the pulse gain is reduced, the pulse number is adjusted, and the switching speed of the power switch tube is reduced; A9. If at least one of the power switch tube junction temperature and the resonant coil temperature is within the corresponding preset over-temperature protection range, then the pulse gain is reduced, the pulse number is minimized, and the switching slope is adjusted to the slowest switching slope.

8. An electromagnetic oven, comprising a power supply module, a power switch module, an LC resonant circuit, an electric parameter sampling circuit and an MCU module, the power switch module is provided with a power switch tube, the LC resonant circuit comprises a resonant coil and a resonant capacitor; characterized in that, The electric parameter sampling circuit is used to collect characteristic electric parameters of the main loop of the electromagnetic cooker; the characteristic electric parameters include bus voltage, resonant current and resonant voltage; The MCU module is used to execute the steps of the low-power continuous heating method based on the adaptive PPG algorithm according to any one of claims 1-7.

9. The electromagnetic stove according to claim 8, characterized in that, The power switch module is further provided with a power device driving circuit, which is used to drive the power switch tube to be on or off under the control of the PWM signal output by the MCU module; the power device driving circuit adopts a push-pull driving architecture and can adjust the gate driving resistance of the power switch tube.

10. The electromagnetic stove according to claim 8, characterized in that, Further comprising a first temperature sensor for collecting the power switch tube junction temperature and a second temperature sensor for collecting the resonant coil temperature.

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