Energy-saving control method for induction cooker based on IGBT loss

Abstract

This application relates to the field of induction cooker control technology, and particularly to an energy-saving control method for induction cookers based on IGBT losses. The method includes: acquiring state data within the current control cycle of the induction cooker; constructing an IGBT loss state vector based on the state data; determining the current operating range based on the target heating power, cookware load state, and the IGBT loss state vector; generating at least two candidate control quantity combinations based on the current operating range, each candidate control quantity combination including candidate switching timing parameters and candidate gate drive parameters; determining a target control quantity combination from among the candidate control quantity combinations based on the IGBT loss state vector, as well as target heating power constraints, soft-switching margin constraints, and thermal margin constraints; driving the IGBT based on the target control quantity combination, and correcting the IGBT loss state vector for the next control cycle based on feedback data after driving. This achieves unified determination of IGBT drive control quantities suitable for the current operating range based on IGBT losses, thereby achieving energy-saving effects.

Description

Technical Field

[0001] This application relates to the field of induction cooker control technology, and in particular to an energy-saving control method for induction cookers based on IGBT losses. Background Technology

[0002] Induction cookers typically employ a power conversion circuit comprised of a rectifier filter circuit, a resonant coil, a resonant capacitor, and power switching devices such as IGBTs (Insulated Gate Bipolar Transistors). The controller drives the IGBTs to switch at high frequency, causing the resonant coil to generate an alternating magnetic field and inducing eddy currents at the bottom of the cookware, resulting in heating. During this process, the IGBTs incur conduction losses, turn-on losses, turn-off losses, and gate drive losses. In standby, cookware detection, light-load continuous heating, and simmering modes, the cookware detection pulse, synchronization detection circuit, gate drive chip, sampling circuit, and auxiliary power supply also contribute to the overall power consumption. Therefore, induction cookers not only need to meet the target heating power but also need to control IGBT losses and auxiliary circuit losses across different operating ranges.

[0003] Existing induction cooker control schemes typically use output power, synchronization edge, zero-crossing detection signal, or fixed drive voltage as the main control objects. For example, some schemes generate synchronization interruption by detecting the resonant voltage and output the turn-on signal after lagging the synchronization signal; some schemes reduce IGBT conduction losses by amplifying the drive voltage in the amplification region, controlling the pulse width, and discharging before zero crossing; and still others achieve low-power output by delaying the turn-on, discharging cycle, or low-power continuous heating cycle. The above schemes can improve the control effect at specific triggering moments or specific power ranges, but their control quantities are usually set around a fixed synchronization sequence, fixed drive voltage, or fixed low-power cycle.

[0004] Because the sources of IGBT losses, soft-switching requirements, thermal margin requirements, and user response requirements are different when the induction cooker switches between standby, pot detection, light-load continuous heating, and normal heating, if the control is still based on a fixed synchronous timing sequence or fixed gate drive parameters, it is difficult for the controller to compare the impact of different switching timing parameters and gate drive parameters on the target heating power, soft-switching margin, device thermal margin, and auxiliary losses within the same control cycle. Therefore, it is difficult to uniformly determine the IGBT drive control quantity suitable for the current operating range based on IGBT losses.

[0005] The above content is only used to help understand the technical solution of this application and does not represent an admission that the above content is prior art. Summary of the Invention

[0006] The main objective of this application is to provide an energy-saving control method for induction cookers based on IGBT losses, aiming to solve the technical problem of how to uniformly determine the IGBT drive control quantity suitable for the current operating range based on IGBT losses.

[0007] To achieve the above objectives, this application proposes an energy-saving control method for induction cookers based on IGBT losses, the method comprising:

[0008] Status data is collected during the current control cycle of the induction cooker. The status data includes at least the operating status of the power conversion circuit, resonant circuit, gate drive circuit, and temperature detection circuit.

[0009] Based on the state data, an IGBT loss state vector is constructed. The IGBT loss state vector includes at least the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin.

[0010] The current operating range is determined based on the target heating power, the cookware load status, and the IGBT loss state vector.

[0011] At least two candidate control quantity combinations are generated based on the current operating range, and each candidate control quantity combination includes candidate switching timing parameters and candidate gate drive parameters;

[0012] Based on the IGBT loss state vector, as well as the target heating power constraint, soft switching margin constraint, and thermal margin constraint, the target control quantity combination is determined from each of the candidate control quantity combinations.

[0013] The IGBT is driven based on the target control quantity combination, and the IGBT loss state vector for the next control cycle is corrected based on the feedback data after the drive.

[0014] In one embodiment, the step of determining the current operating range based on the target heating power, the cookware load state, and the IGBT loss state vector includes:

[0015] The cookware load status is determined based on the cookware detection signal, the resonant circuit response, and the user's power setting.

[0016] The current operating range is determined based on the target heating power and the cookware load status;

[0017] When the confidence level of no pot is higher than the threshold of no pot and no heating trigger signal is detected, the current operating range is determined to be the standby range;

[0018] When it is necessary to confirm the presence, location, or material of the cookware, the current operating range is designated as the cookware inspection range.

[0019] When the cookware is present and the target average heating power is lower than the low power threshold, the current operating range is determined to be a light-load continuous heating range;

[0020] When a cookware is present, the target heating power is greater than or equal to the low power threshold, and the soft switching margin and the heat margin meet the corresponding thresholds, the current operating range is determined to be the normal heating range.

[0021] When overvoltage, overcurrent, overtemperature, insufficient soft switching margin, or abnormal gate drive is detected, the current operating range is determined to be an abnormal protection range.

[0022] In one embodiment, the step of constructing the IGBT loss state vector based on the state data includes:

[0023] The on-state loss estimate is determined based on the mapping relationship between the IGBT collector current, conduction pulse width, control period, and saturation voltage drop corresponding to the current gate drive voltage.

[0024] The estimated switching loss is determined based on the collector voltage before IGBT turn-on, collector current at turn-off, switching frequency, gate drive voltage, equivalent gate resistance, estimated junction temperature, and soft switching margin.

[0025] The gate drive loss estimate is determined based on the gate charge, gate drive voltage, switching frequency, and gate drive circuit efficiency.

[0026] The estimated standby auxiliary loss is determined based on the wake-up duty cycle and static current of the gate driver chip, sampling circuit, synchronization detection circuit, display circuit, or communication circuit within the standby interval.

[0027] The IGBT loss state vector is generated based on the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin.

[0028] In one embodiment, the step of generating at least two candidate control quantity combinations based on the current operating range includes:

[0029] Within the parameter range corresponding to the current operating interval, candidate switch timing parameters are generated. The candidate switch timing parameters include at least four of the following: synchronization edge advance, synchronization edge lag, valley selection sequence number, conduction pulse width, turn-off window, switching frequency, number of pulse clusters, intermittent heating cycle, boiler detection cycle, and low-energy detection pulse width.

[0030] Within the gate drive range corresponding to the current operating interval, candidate gate drive parameters are generated. The candidate gate drive parameters include at least three of the following: pre-drive voltage, turn-on drive voltage, hold drive voltage, turn-off drive voltage, turn-on drive current, turn-off drive current, equivalent gate resistance, pre-drive duration, and drive voltage switching time.

[0031] The candidate switch timing parameters and the candidate gate drive parameters are combined to obtain at least two combinations of the candidate control quantities.

[0032] In one embodiment, the step of determining the target control quantity combination from each of the candidate control quantity combinations based on the IGBT loss state vector, as well as the target heating power constraint, soft switching margin constraint, and thermal margin constraint, includes:

[0033] For each candidate control quantity combination, predict the predicted heating energy deviation, predicted soft switching margin, predicted thermal margin, and overall loss value respectively.

[0034] Candidate control quantity combinations that are excluded include those where the predicted heating energy deviation exceeds the corresponding power deviation threshold, the predicted soft switching margin is lower than the corresponding soft switching margin threshold, and the predicted thermal margin is lower than the corresponding thermal margin threshold.

[0035] From the remaining candidate control variable combinations, the target control variable combination is determined based on the comprehensive loss value and preset selection conditions.

[0036] In one embodiment, the overall loss value is determined according to an objective function, which is:

[0037] ;

[0038] in, This is the estimate of the on-state loss. For the estimation of commissioning losses, This is an estimate of the turn-off loss. This is the estimate of the gate drive loss. This is the estimated amount of standby auxiliary loss. As a heat-related risk item, The target heating energy deviation term, to The weight corresponding to the current operating interval.

[0039] In one embodiment, the step of driving the IGBT based on the target control quantity combination includes:

[0040] During the pre-discharge phase before IGBT turn-on, the IGBT is driven based on the pre-drive voltage and pre-drive duration in the target control quantity combination.

[0041] When the load current, resonant voltage, or conduction pulse width meets the preset switching conditions, the switch is made to the turn-on drive voltage in the target control quantity combination.

[0042] During the light load holding phase, the IGBT is kept on according to the holding drive voltage or equivalent gate resistance in the target control quantity combination.

[0043] In one embodiment, the step of correcting the IGBT loss state vector for the next control cycle based on the feedback data after driving includes:

[0044] The feedback data is determined based on the heat sink temperature, ambient temperature, peak IGBT collector voltage, peak IGBT collector current, and soft-switching margin after the drive.

[0045] Based on the thermal resistance and thermal capacity model and the IGBT loss state vector in the current control cycle, the IGBT junction temperature is estimated.

[0046] Based on the residual between the estimated temperature rise and the measured temperature rise, correct the saturation voltage drop mapping, switching energy mapping, gate drive loss coefficient, and / or the loss weight corresponding to the current operating range.

[0047] In one embodiment, the energy-saving control method for induction cookers based on IGBT losses further includes:

[0048] When the current operating interval is a standby interval or a boiler detection interval, the boiler detection cycle is determined based on the no-boiler confidence, the most recent boiler detection response, and the standby auxiliary loss estimate. When the no-boiler status is continuously confirmed, at least one of the gate drive circuit, sampling circuit, or synchronous detection circuit is controlled to enter sleep mode.

[0049] When the confidence level of no pot decreases or a heating trigger signal is detected, the pot detection cycle is shortened, and a low-energy detection pulse is generated based on a short conduction pulse width, a low pre-drive voltage, and a predetermined valley trigger window.

[0050] In one embodiment, the energy-saving control method for induction cookers based on IGBT losses further includes:

[0051] When the current operating range is a light-load continuous heating range, the comprehensive loss value corresponding to shortening the conduction pulse width, increasing the intermittent heating cycle, changing the valley selection sequence, adjusting the switching frequency, and adjusting the gate drive voltage is compared based on the target average heating power.

[0052] When shortening the conduction pulse width causes the IGBT to remain in the linear region for longer than the linear region threshold, or when changing the valley selection sequence causes the IGBT to deviate from the zero-voltage turn-on window, the selection priority of the corresponding candidate control quantity combination should be reduced.

[0053] One or more technical solutions proposed in this application have at least the following technical effects:

[0054] By constructing an IGBT loss state vector based on state data, simultaneously representing conduction loss, switching loss, gate drive loss, standby auxiliary loss, soft-switching margin, and thermal margin, and determining the current operating range based on the target heating power, cookware load state, and IGBT loss state vector, the system unifies the sources of IGBT losses, soft-switching conditions, and thermal state into a calculable basis, avoiding the need to drive the IGBT solely at a fixed power level or fixed synchronization point. Under the current operating range, at least two candidate control quantity combinations, including candidate switching timing parameters and candidate gate drive parameters, are generated. A target control quantity combination is determined under the constraints of target heating power, soft-switching margin, and thermal margin. The combined effects of control quantities such as valley selection, conduction pulse width, switching frequency, cookware inspection cycle, pre-drive voltage, hold drive voltage, and equivalent gate resistance on IGBT losses are compared to reduce the risks of hard switching, linear region conduction, and device temperature rise. By driving the IGBT based on a combination of target control variables and correcting the IGBT loss state vector for the next control cycle based on feedback data after the drive, the stability and reliability of the induction cooker's energy-saving control are improved by adapting to changes in cookware material, bus voltage, device discreteness, heat dissipation conditions, and device aging. In summary, through a closed loop of collecting state data, constructing loss state vectors, determining operating ranges, generating candidate combinations, optimizing under constraints, and feedback correction, the impact of different switching timing parameters and gate drive parameters on target power, soft switching, thermal margin, and auxiliary losses is compared within the same control cycle. This allows for the unified determination of drive control variables suitable for the current operating range based on IGBT losses. Attached Figure Description

[0055] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0056] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] Figure 1 This is a flowchart illustrating the first embodiment of the energy-saving control method for induction cookers based on IGBT losses in this application.

[0058] Figure 2 This is a flowchart illustrating an embodiment of the energy-saving control method for an induction cooker based on IGBT losses according to this application.

[0059] Figure 3 This is a schematic flowchart of another embodiment of the energy-saving control method for induction cookers based on IGBT losses in this application.

[0060] Figure 4 This is a flowchart illustrating the second embodiment of the energy-saving control method for induction cookers based on IGBT losses in this application.

[0061] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0062] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application.

[0063] To better understand the technical solution of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0064] In this embodiment, the induction cooker may include a rectifier and filter circuit, a resonant circuit consisting of a resonant coil and a resonant capacitor, an IGBT, a gate drive circuit, a bus sampling circuit, a coil sampling circuit, a resonant synchronization detection circuit, a temperature detection circuit, a cookware detection circuit, and a controller. The controller may be a microcontroller, a digital signal processor, a dedicated control chip, a programmable logic device, or a combination thereof. The controller obtains status data through an analog-to-digital sampling port, a comparator input port, a timer capture port, or a communication port, and controls the IGBT and related auxiliary circuits through a PWM output port, a gate drive control port, or a power enable port.

[0065] It should be noted that the "current control cycle" in this application refers to the decision cycle in which the controller makes a loss estimate and a control quantity selection. This cycle may include one or more IGBT switching cycles, or it may include a boiler detection cycle or an average power calculation cycle. Different products can set the length of the control cycle according to the sampling speed, computing power, and power control accuracy. As long as the status acquisition, loss estimation, candidate control quantity evaluation, drive execution, and feedback update can be completed within this control cycle, the solution in this application can be implemented.

[0066] It should be noted that the execution subject of the embodiments of this application can be an electronic device with data processing, network communication and program running functions, such as an induction cooker, tablet computer, personal computer, mobile phone, etc., or an electronic device capable of realizing the above functions.

[0067] Based on this, the embodiments of this application provide an energy-saving control method for induction cookers based on IGBT losses, referring to... Figure 1 , Figure 1This is a flowchart illustrating the first embodiment of the energy-saving control method for induction cookers based on IGBT losses according to this application. In this embodiment, the energy-saving control method for induction cookers based on IGBT losses includes steps S100 to S600:

[0068] Step S100: Collect status data within the current control cycle of the induction cooker. The status data includes at least the operating status of the power conversion circuit, resonant circuit, gate drive circuit, and temperature detection circuit.

[0069] In this embodiment, the operating status of the power conversion circuit may include DC bus voltage, DC bus current, IGBT collector voltage, and IGBT collector current; the operating status of the resonant circuit may include coil current, coil voltage, resonant voltage, resonant voltage valley, resonant synchronization edge, and resonant decay time; the operating status of the gate drive circuit may include gate drive voltage, gate drive current, equivalent gate resistance, driver chip enable state, and drive voltage switching time; the operating status of the temperature detection circuit may include heat sink temperature, ambient temperature, case temperature, or other temperature signals that can reflect the thermal state of the IGBT. All of the above data can be collected, or only a subset that supports loss estimation and control decisions can be collected based on the product hardware conditions.

[0070] Step S200: Construct an IGBT loss state vector based on the state data. The IGBT loss state vector includes at least the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin.

[0071] It should be noted that the actual energy consumption of an induction cooker is not solely determined by its output power. For example, frequent pot checks under low power conditions increase auxiliary losses; excessively short conduction pulse widths during continuous heating under light load may cause the IGBT to turn on before it is fully saturated; and deviation from the resonance valley during normal heating increases turn-on losses. Therefore, by constructing an IGBT loss state vector, conduction losses, switching losses, gate drive losses, standby auxiliary losses, soft-switching margin, and thermal margin are placed in the same state set, thus providing a unified basis for subsequent comparison of candidate control quantities.

[0072] Step S300: Determine the current operating range based on the target heating power, the cookware load status, and the IGBT loss state vector.

[0073] Optionally, the current operating range may include at least a standby range, a boiler inspection range, a light-load continuous heating range, a normal heating range, and an abnormal protection range. The operating range is used to define which loss issues should be prioritized in this control cycle. For example, the standby range primarily reduces auxiliary circuit wake-up losses, the boiler inspection range primarily reduces probe pulse energy, the light-load continuous heating range primarily reduces switching and gate losses under low-power continuous operation, the normal heating range primarily controls conduction losses, turn-off losses, and thermal margin, and the abnormal protection range primarily ensures device safety.

[0074] Step S400: Generate at least two candidate control quantity combinations based on the current operating range. Each candidate control quantity combination includes candidate switching timing parameters and candidate gate drive parameters.

[0075] For example, in the light-load continuous heating range, one candidate control combination can select the current resonant valley, shorten the conduction pulse width, use a low pre-drive voltage, and switch to the turn-on drive voltage after the current rises; another candidate control combination can select the next resonant valley, maintain the conduction pulse width, reduce the switching frequency, and use a holding drive voltage. Since the heating energy of the two combinations is similar, but their effects on turn-on losses, gate losses, and thermal margin are different, they need to be evaluated further.

[0076] Step S500: Based on the IGBT loss state vector, as well as the target heating power constraint, soft switching margin constraint, and thermal margin constraint, determine the target control quantity combination from each of the candidate control quantity combinations.

[0077] Understandably, the target heating power constraint is used to prevent energy-saving control from causing the actual heating energy to deviate from the target; the soft-switching margin constraint is used to prevent the IGBT from turning on when the collector voltage is high; and the thermal margin constraint is used to prevent the device junction temperature or heat sink temperature from approaching its limit. Only candidate control quantity combinations that simultaneously satisfy the above constraints are considered for loss optimization.

[0078] Step S600: Drive the IGBT based on the target control quantity combination, and correct the IGBT loss state vector for the next control cycle based on the feedback data after driving.

[0079] In this embodiment, the feedback data after the drive can reflect the execution effect of the current control cycle, such as whether the peak collector voltage increases, whether the peak collector current is abnormal, whether the soft-switching margin decreases, and whether the heat sink temperature rise is higher than the estimated value. The controller uses this feedback for the next control cycle, so that the loss estimation and parameter selection continuously match the actual circuit state.

[0080] In the technical solution provided in this embodiment, an IGBT loss state vector is constructed based on state data, simultaneously representing conduction loss, switching loss, gate drive loss, standby auxiliary loss, soft-switching margin, and thermal margin. The current operating range is determined based on the target heating power, cookware load state, and IGBT loss state vector. This unifies the sources of IGBT loss, soft-switching conditions, and thermal state into a calculable basis, avoiding the need to drive the IGBT solely at a fixed power level or fixed synchronization point. At least two candidate control quantity combinations, including candidate switching timing parameters and candidate gate drive parameters, are generated within the current operating range. A target control quantity combination is determined under the constraints of target heating power, soft-switching margin, and thermal margin. The combined effects of control quantities such as valley selection, conduction pulse width, switching frequency, cookware inspection cycle, pre-drive voltage, hold drive voltage, and equivalent gate resistance on IGBT loss are compared to reduce the risks of hard switching, linear region conduction, and device temperature rise. By driving the IGBT based on a combination of target control variables and correcting the IGBT loss state vector for the next control cycle based on feedback data after the drive, the stability and reliability of the induction cooker's energy-saving control are improved by adapting to changes in cookware material, bus voltage, device discreteness, heat dissipation conditions, and device aging. In summary, through a closed loop of collecting state data, constructing loss state vectors, determining operating ranges, generating candidate combinations, optimizing under constraints, and feedback correction, the impact of different switching timing parameters and gate drive parameters on target power, soft switching, thermal margin, and auxiliary losses is compared within the same control cycle. This allows for the unified determination of drive control variables suitable for the current operating range based on IGBT losses.

[0081] In one feasible implementation, step S300 may include steps S310 and S320:

[0082] Step S310: Determine the cookware load status based on the cookware detection signal, the resonant circuit response, and the user power setting;

[0083] Step S320: Determine the current operating range based on the target heating power and the load status of the cookware.

[0084] It should be noted that the cookware detection signal can originate from proximity detection circuits, coil current changes, resonant decay time, resonant frequency shift, voltage or current response after a cookware detection pulse, etc.; the resonant circuit response can reflect the presence of a cookware, whether the cookware position is off-center, and the influence of the cookware material on the coil's equivalent impedance; the user power setting is used to determine the target heating power or target average heating power. The controller converts the above information into cookware load status, such as no cookware, suspected cookware, cookware but off-center position, cookware suitable for heating, and abnormal resonant response caused by the cookware material.

[0085] Specifically, when the no-pot confidence level is higher than the no-pot threshold and no heating trigger signal is detected, the current operating range is determined to be the standby range. The no-pot confidence level can be calculated by weighting the current rise after the pot detection pulse, the resonant voltage decay rate, the resonant frequency offset, the pot proximity detection result, and historical pot detection results. The no-pot threshold can be obtained through product calibration or corrected at the factory based on the pot detection misjudgment rate. Identifying the standby range separately allows the controller to reduce the wake-up duty cycle of the gate drive circuit and sampling circuit, thereby reducing standby auxiliary losses.

[0086] When it is necessary to confirm the presence, location, or material of the cookware, the current operating range is designated as the cookware inspection range. Specifically, when the confidence level for no cookware is insufficient to directly determine its absence, or when changes in cookware placement, location, or material are detected, the controller designates the current operating range as the cookware inspection range. During the cookware inspection range, the controller does not directly enter normal heating mode. Instead, it confirms the presence, location, or material of the cookware through low-energy detection pulses and resonant responses. This avoids applying high-energy pulses when the cookware status is uncertain, reducing the risk of accidental heating and hard switching.

[0087] When a cookware is present and the target average heating power is below the low power threshold, the current operating range is determined to be a light-load continuous heating range. The low power threshold can be calibrated based on the product's rated power, resonant circuit parameters, IGBT thermal capability, and minimum stable heating energy. The purpose of the light-load continuous heating range is to achieve average power not only through prolonged shutdown and short-duration high-power pulses in low-average power scenarios such as heat preservation, simmering, and slow cooking, but also by comparing the impact of combinations of conduction pulse width, valley selection, switching frequency, and gate drive voltage on losses.

[0088] When a cookware is present, the target heating power is greater than or equal to the low power threshold, and the soft-switching margin and the thermal margin meet their corresponding thresholds, the current operating range is determined to be the normal heating range. When overvoltage, overcurrent, overtemperature, insufficient soft-switching margin, or gate drive abnormality is detected, the current operating range is determined to be the abnormal protection range. In the normal heating range, the controller can prioritize controlling conduction losses, turn-off losses, and thermal risks while ensuring the target power. In the abnormal protection range, the controller can directly reduce the target power, expand the turn-off window, change the valley selection, limit the conduction pulse width, or turn off the IGBT if the risk persists.

[0089] Thus, in this embodiment, the target heating power, cookware load state, and IGBT loss state vector jointly determine the current operating range through the aforementioned partitioning. This allows for separate processing of the main causes of loss under different operating states: standby and cookware detection focus on auxiliary losses and detection energy; light-load continuous heating focuses on switching losses and linear region risks under low power; normal heating focuses on on-state losses and thermal margin; and anomaly protection focuses on safety constraints. This achieves the goal of not needing to use the same set of fixed drive parameters to cover all scenarios.

[0090] As an optional implementation, step S200 may include steps S210 to S250:

[0091] Step S210: Determine the on-state loss estimate based on the mapping relationship between the IGBT collector current, conduction pulse width, control period and the saturation voltage drop corresponding to the current gate drive voltage.

[0092] It should be noted that conduction losses are the losses generated by the collector current and collector-emitter saturation voltage drop when the IGBT is in the on state. For example, the saturation voltage drop mapping relationship can be expressed as follows: ,in This is the collector current of the IGBT. This is the gate drive voltage. To estimate the junction temperature, the controller operates within the conduction window. and The products are accumulated and divided by the control cycle length to obtain... If the gate drive voltage is too low or the junction temperature rises, the saturation voltage drop in the mapping relationship increases, and the on-state loss estimate increases accordingly.

[0093] Step S220: Determine the estimated switching loss based on the collector voltage before IGBT turn-on, collector current at turn-off, switching frequency, gate drive voltage, equivalent gate resistance, estimated junction temperature, and soft switching margin.

[0094] Switching losses may include estimates of turn-on losses. and turn-off loss estimate Turn-on losses are related to the collector voltage before IGBT turn-on, the instantaneous turn-on current, the gate drive speed, the equivalent gate resistance, the estimated junction temperature, and whether the turn-on voltage is close to zero. Turn-off losses are related to the collector current at turn-off, the rise time of the collector voltage, the gate turn-off current, the equivalent gate resistance, and the estimated junction temperature. The single-turn-on energy can be obtained by looking up tables, using piecewise linear functions, or by calibrating a model. and single shutdown energy Then, combined with the switching frequency, an estimate of the switching loss is obtained. If the soft-switching margin is large, it can be reduced. If the valley selection is off-target or the propagation delay compensation is insufficient, it can improve... .

[0095] Step S230: Determine the estimated gate drive loss based on the gate charge, gate drive voltage, switching frequency, and gate drive circuit efficiency.

[0096] The gate drive loss estimate can be obtained using the formula To make an estimate, among which For equivalent gate charge, This is the gate drive voltage. For switching frequency, This refers to the efficiency of the gate drive circuit. When using a higher gate drive voltage or a higher switching frequency... Increase; when the light-load holding phase allows for a reduction in the holding drive voltage, it can be reduced. .

[0097] Step S240: Determine the estimated standby auxiliary loss based on the wake-up duty cycle and static current of the gate driver chip, sampling circuit, synchronization detection circuit, display circuit, or communication circuit within the standby interval.

[0098] For example, the losses of an auxiliary circuit can be estimated by multiplying its supply voltage, quiescent current, and wake-up duty cycle; the energy of a low-energy pot detection pulse can also be converted into the corresponding standby or pot detection cycle. Therefore, It reflects not only the static current, but also the boiler detection frequency, sampling wake-up frequency, and display communication wake-up strategy.

[0099] Step S250: Generate the IGBT loss state vector based on the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin.

[0100] In this embodiment, the soft-switching margin can be represented by the voltage margin between the collector voltage and the predetermined zero-voltage window before IGBT turn-on, or by the time margin between the synchronization edge, propagation delay, and valley window. Alternatively, the voltage and time margins can be normalized and the smaller value taken. The thermal margin can be represented as the difference between the allowable junction temperature or allowable heatsink temperature and the estimated temperature. The IGBT loss state vector can be represented as: ,in It can be further broken down into and ; For soft switching margin, This is the thermal margin.

[0101] Thus, the embodiments of this application convert losses and margins from different sources and with different dimensions into state quantities that the controller can calculate and compare. In this way, when selecting candidate combinations of control quantities, the controller can not only see whether a certain combination meets the target power, but also see whether the combination will increase turn-on losses, gate drive losses, standby auxiliary losses, or thermal risks.

[0102] In an optional implementation, step S400 may include steps S410 to S430:

[0103] Step S410: Within the parameter range corresponding to the current operating interval, generate candidate switch timing parameters. The candidate switch timing parameters include at least four of the following: synchronization edge advance, synchronization edge lag, valley selection sequence number, conduction pulse width, turn-off window, switching frequency, number of pulse clusters, intermittent heating cycle, boiler detection cycle, and low-energy detection pulse width.

[0104] Step S420: Within the gate drive range corresponding to the current operating interval, candidate gate drive parameters are generated. The candidate gate drive parameters include at least three of the following: pre-drive voltage, turn-on drive voltage, hold drive voltage, turn-off drive voltage, turn-on drive current, turn-off drive current, equivalent gate resistance, pre-drive duration, and drive voltage switching time.

[0105] Step S430: Combine the candidate switch timing parameters and the candidate gate drive parameters to obtain at least two candidate control quantity combinations.

[0106] In this embodiment, the range of switching timing parameters can be determined first based on the current operating range. For example, the standby range and the boiler detection range can allow for a longer boiler detection period, a shorter low-energy detection pulse width, and a smaller number of pulse clusters; the light-load continuous heating range can allow for multiple valley selection numbers, a smaller on-state pulse width adjustment, a wider range of intermittent heating periods, and a lower range of switching frequencies; the normal heating range can allow for on-state pulse widths, turn-off windows, and synchronization edge compensation ranges that are closer to the target power; and the abnormal protection range can only allow conservative control values ​​such as power reduction, extended turn-off window, or IGBT shutdown.

[0107] Candidate switch timing parameters can be selected from at least four of the following: synchronization edge advance, synchronization edge lag, valley selection sequence number, conduction pulse width, turn-off window, switching frequency, number of pulse clusters, intermittent heating cycle, boiler detection cycle, and low-energy detection pulse width. Here, "at least four" does not require that exactly the same four parameters be used for each operating range, but rather that the candidate switch timing parameters are sufficient to simultaneously characterize the trigger time, conduction energy, turn-off safety, and average power or boiler detection rhythm.

[0108] Candidate gate drive parameters can be selected from at least three of the following: pre-drive voltage, turn-on drive voltage, hold drive voltage, turn-off drive voltage, turn-on drive current, turn-off drive current, equivalent gate resistance, pre-drive duration, and drive voltage switching time. The phrase "at least three" ensures that the candidate gate drive parameters not only change the drive voltage level but also alter the turn-on speed, turn-off speed, and drive energy at different conduction stages.

[0109] After obtaining the candidate switch timing parameters and candidate gate drive parameters, the controller can obtain at least two candidate control quantity combinations through combination operations. Combination operations can be Cartesian combinations, lookup table combinations, combinations of local disturbances around the target control quantity of the previous control cycle, or combinations formed by first filtering out obviously unsafe parameters according to empirical rules. For example, if the collector voltage corresponding to a certain valley selection number is still higher than the zero-voltage window, the controller may not combine it with an aggressive turn-on drive current; if a certain holding drive voltage easily causes the IGBT to exit the saturation region, the controller may only use it in combinations with short holding times under light loads.

[0110] In this embodiment, the candidate control quantity combination covers both the switching timing and gate drive control dimensions. Adjusting the synchronization edge alone may reduce turn-on losses but not gate drive losses, while reducing the gate drive voltage alone may reduce gate losses but increase on-state losses or linear region risks. Combining the two and then evaluating them can avoid the overall loss increase caused by local optimization.

[0111] Reference Figure 2 In one feasible implementation, step S500 may include steps S510 to S530:

[0112] Step S510: Predict the predicted heating energy deviation, predicted soft switching margin, predicted thermal margin, and comprehensive loss value for each candidate control quantity combination.

[0113] Step S520: Eliminate candidate control quantity combinations that include the predicted heating energy deviation exceeding the corresponding power deviation threshold, the predicted soft switching margin being lower than the corresponding soft switching margin threshold, and the predicted thermal margin being lower than the corresponding thermal margin threshold.

[0114] Step S530: Among the remaining candidate control quantity combinations, the target control quantity combination is determined based on the comprehensive loss value and preset selection conditions.

[0115] In this embodiment, four types of results are predicted for each candidate control quantity combination: predicted heating energy deviation, predicted soft-switching margin, predicted thermal margin, and overall loss value. The predicted heating energy deviation can be estimated from the candidate conduction pulse width, switching frequency, number of pulse clusters, intermittent heating cycle, cookware load state, and bus voltage; the predicted soft-switching margin can be estimated from the candidate valley selection sequence number, synchronization edge advance or lag, propagation delay, resonant voltage valley value, and coil current direction; the predicted thermal margin can be estimated from the currently estimated junction temperature, the on-state loss and switching loss corresponding to the candidate combination, the radiator temperature, and the thermal model; the overall loss value can be determined by the objective function. Obtained. Among them, This is the estimate of the on-state loss. For the estimation of commissioning losses, This is an estimate of the turn-off loss. This is the estimate of the gate drive loss. This is the estimated amount of standby auxiliary loss. As a heat-related risk item, The target heating energy deviation term, to The weights are those corresponding to the current operating range. Each loss term can be the actual power value, or it can be normalized and then summed. The weights can be non-negative and can be obtained through factory calibration, operating range rules, or feedback correction.

[0116] In the standby period It can be higher than the corresponding values ​​of other intervals. This makes the objective function focus more on standby auxiliary losses. When the boiler detection response is stable and the confidence level of no boiler is high, increase... The weighting will cause the controller to tend to extend the boiler detection cycle and shut down unnecessary auxiliary circuits. Understandably, It is mainly determined by the auxiliary circuit supply voltage, quiescent current, and wake-up duty cycle. Reducing the wake-up duty cycle will directly reduce the... Therefore, the standby time is increased. It can guide the controller to select a low wake-up duty cycle combination.

[0117] In the boiler inspection zone, it is possible to simultaneously improve and Corresponding weights. Used to limit auxiliary losses caused by frequent probes This is used to limit identification instability caused by excessively low probe pulse energy. In this way, the controller does not simply reduce the probe pulse to a minimum, but rather selects a suitable combination between detection reliability and probe energy.

[0118] In the light-load continuous heating zone, it can improve , , and This allows the objective function to focus more on switching losses, gate drive losses, and deviations from the target average heating energy. Understandably, the energy of a single turn-on pulse is small under light load. If a higher switching frequency and gate drive voltage are still used, the proportion of gate drive losses in the total losses will increase. Conversely, reducing the average power by using excessively short turn-on pulse widths may cause the IGBT to turn on before it is fully saturated, increasing conduction losses and thermal risks. Therefore, in the light load range, a weighted controller is needed to compare various low-power implementation methods.

[0119] Within the normal heating range, it can increase , and This allows the objective function to focus more on on-state losses, turn-off losses, and thermal risks. The current is relatively high during normal heating. and The effect on temperature rise is more pronounced; Increasing this value indicates a decrease in heat margin. Even if the instantaneous loss of a particular combination is low, the risk may increase due to sustained temperature rise. Therefore, increasing... This allows the controller to pre-select a more conservative conduction pulse width, switching frequency, or drive parameters.

[0120] Through the aforementioned objective function, different operating ranges do not use the exact same energy-saving standard, but rather change the weights within the same functional framework. This achieves the goal of ensuring computability and comparability at the upper level using a unified objective function, reflecting different main causes of loss at the middle level using operating range weights, and guiding the selection of switching timing and gate drive parameters at the lower level using specific loss terms.

[0121] In this embodiment, after obtaining the prediction results, the controller first performs constraint elimination. If the predicted heating energy deviation of a candidate control quantity combination exceeds the corresponding power deviation threshold, it indicates that although the combination may have low losses, it cannot meet the target heating energy for this control cycle, and therefore it is eliminated. If the predicted soft-switching margin is lower than the corresponding soft-switching margin threshold, it indicates that the combination may cause the IGBT to deviate from the zero-voltage turn-on window, resulting in increased overlap of voltage and current at the turn-on moment, and therefore it is eliminated. If the predicted thermal margin is lower than the corresponding thermal margin threshold, it indicates that the combination may cause the junction temperature or heat sink temperature to approach the limit, and therefore it is eliminated.

[0122] Among the remaining candidate control combinations, the controller determines the target control combination based on the overall loss value and preset selection criteria. Preset selection criteria can be: minimizing the overall loss value; prioritizing combinations with smaller differences from the previous control cycle when overall loss values ​​are close, to reduce frequent changes in drive parameters; or prioritizing combinations with the largest thermal margin within the abnormal protection range. If all candidate control combinations are eliminated, the controller can enter a conservative degradation strategy, such as reducing the target heating power, extending the shutdown window, increasing valley waiting time, reducing the switching frequency, or shutting down the IGBT.

[0123] Thus, the embodiments of this application first use the target heating power, soft switching margin, and thermal margin to eliminate combinations that do not meet the basic constraints, thereby avoiding sacrificing heating controllability or device safety in pursuit of low losses; then compare the comprehensive loss value among the remaining combinations to ensure that energy-saving selection occurs within an available and safe control range.

[0124] As an optional implementation, the step of driving the IGBT based on the target control quantity combination may include steps S611 to S613:

[0125] Step S611: In the pre-discharge stage before IGBT is turned on, the IGBT is driven based on the pre-drive voltage and pre-drive duration in the target control quantity combination.

[0126] Step S612: When the load current, resonant voltage, or conduction pulse width meets the preset switching conditions, switch to the turn-on drive voltage in the target control quantity combination.

[0127] Step S613: During the light load holding phase, the IGBT is kept on according to the holding drive voltage or equivalent gate resistance in the target control quantity combination.

[0128] It should be noted that the pre-discharge phase is a controlled preparation phase before formal turn-on. The controller uses a low or limited pre-drive voltage to ensure that the gate potential, collector voltage, and resonant circuit state enter the turn-on window as expected. For circuits with zero-crossing pre-discharge or valley triggering requirements, the pre-drive duration can be coordinated with the resonant synchronization edge, propagation delay, and valley selection sequence to ensure that the IGBT turns on when the collector voltage is as low as possible.

[0129] In this embodiment, the preset switching conditions may include: the load current reaching a set rising slope or current threshold, the resonant voltage entering a predetermined valley window, the conduction pulse width reaching the pre-drive duration, or a combination of the above conditions. After switching to the turn-on drive voltage, the IGBT can enter the saturation conduction state more quickly, thereby reducing the conduction losses and temperature rise caused by staying in the linear region for a long time.

[0130] The holding drive voltage can be lower than the turn-on drive voltage, but the IGBT should still be in a saturated or near-saturated state to meet the current requirements. The equivalent gate resistance can be achieved by selecting the drive branch, changing the drive current, or changing the gate series impedance. If the holding drive voltage is too low, the saturation voltage drop will increase, the on-state loss estimate will increase in the next control cycle, and this combination will be discouraged from being selected again.

[0131] Thus, this embodiment reduces turn-on losses by minimizing the overlap of voltage and current during the pre-drive phase; it reduces conduction losses and thermal risks by increasing the turn-on drive voltage after the switching conditions are met, thereby shortening the time the IGBT remains in the linear region; and it further reduces gate drive losses by reducing unnecessary drive energy during the light load holding phase. These three factors work together to ensure that the gate drive parameters are no longer fixed values, but rather coordinated with the switching timing and load conditions.

[0132] Reference Figure 3 Furthermore, the step of correcting the IGBT loss state vector for the next control cycle based on the feedback data after the drive may include steps S621 to S623:

[0133] Step S621: Determine feedback data based on the heat sink temperature, ambient temperature, peak IGBT collector voltage, peak IGBT collector current, and soft switching margin after driving.

[0134] Step S622: Estimate the IGBT junction temperature based on the thermal resistance and thermal capacity model and the IGBT loss state vector in the current control cycle;

[0135] Step S623: Based on the residual between the estimated temperature rise and the measured temperature rise, correct the saturation voltage drop mapping, switching energy mapping, gate drive loss coefficient and / or the loss weight corresponding to the current operating range.

[0136] Understandably, radiator temperature and ambient temperature are used to determine the accuracy of the thermal model; IGBT collector voltage peak can reflect turn-off spikes and resonant states; IGBT collector current peak can reflect changes in cookware load and conduction energy; soft-switching margin can reflect whether the actual turn-on time falls within the predetermined zero-voltage window.

[0137] In this embodiment, the thermal resistance and thermal capacity model can be a first-order model or a multi-order model. For example, a first-order model can include ambient temperature, heat sink temperature, average loss, thermal resistance parameters, and thermal capacity parameters; a multi-order model can further distinguish the thermal paths from chip to casing, casing to heat sink, and heat sink to environment. Regardless of the order used, the purpose is to convert the losses of the current cycle and historical cycles into estimated junction temperature or estimated temperature rise.

[0138] For example, if the estimated temperature rise is consistently lower than the measured temperature rise, it indicates that the current loss model may underestimate the on-state loss or switching loss, thereby increasing the temperature correction in the saturation voltage drop mapping and increasing the temperature correction in the switching energy mapping. or The correction amount can be adjusted, or the weight of the thermal risk term can be increased. If the measured temperature rise is lower than the estimated temperature rise, the controller can slowly reduce the corresponding correction amount, but the correction range can be limited to avoid excessive model fluctuations.

[0139] Optionally, the controller can perform low-pass filtering on the residuals before correcting the parameters, and set upper and lower limits for correction. This is to avoid abrupt changes in the loss model caused by a single pot movement, transient fluctuations in the bus, or temperature sampling noise. The corrected IGBT loss state vector is used for determining the operating range, generating candidate combinations, and calculating the objective function in the next control cycle.

[0140] In this way, the loss model no longer relies entirely on the factory calibration. The material of the cookware, coil coupling, batch differences of components, the condition of thermal grease, dust accumulation in the air duct, and long-term aging will all change the relationship between the actual temperature rise and the model estimate; through residual correction, the controller can gradually pull the loss estimate of the next control cycle back to the actual state, thereby improving the stability of energy-saving control and protection control.

[0141] Reference Figure 4 Based on the first embodiment of this application, in the second embodiment of this application, the content that is the same as or similar to the above embodiment can be referred to the above description, and will not be repeated hereafter. On this basis, the energy-saving control method for induction cookers based on IGBT losses may further include steps S710 and S720:

[0142] Step S710: When the current operating interval is a standby interval or a boiler detection interval, the boiler detection cycle is determined based on the no-boiler confidence, the most recent boiler detection response, and the standby auxiliary loss estimate. When the boiler is continuously confirmed to be no, at least one of the gate drive circuit, sampling circuit, or synchronous detection circuit is controlled to enter sleep mode.

[0143] Step S720: When the confidence level of no pot decreases or a heating trigger signal is detected, the pot detection period is shortened, and a low-energy detection pulse is generated based on the short conduction pulse width, low pre-drive voltage and predetermined valley trigger window.

[0144] In this embodiment, the higher the confidence level of no-pot detection, the more consistently the most recent pot detection response points to no pot detection, and the larger the estimated standby auxiliary loss, the more likely the controller is to extend the pot detection period. Conversely, if the confidence level of no-pot detection decreases and the most recent pot detection response shows characteristics suggestive of a pot presence, the controller will shorten the pot detection period. Understandably, a shorter pot detection period results in more frequent wake-ups of the sampling circuit, synchronous detection circuit, and gate drive circuit. The larger the detection period, the slower the recognition speed of changes in the cookware's state will be; therefore, it is necessary to adjust the confidence level and the most recent response.

[0145] Entering sleep mode can be achieved by disabling the enable pin of the driver chip, reducing the power supply to the sampling circuit, disabling the high-speed comparator, reducing the synchronization detection frequency, or disabling unnecessary communication wake-up. Since the estimated standby auxiliary loss is related to the quiescent current and the wake-up duty cycle, disabling at least one of these can directly reduce [the loss]. ... .

[0146] It should be noted that the short conduction pulse width limits the single detection energy, the low pre-drive voltage limits the gate drive energy and current rise rate, and the predetermined valley trigger window reduces the detection pulse turn-on loss. After the detection pulse is executed, the controller updates the cookware load status and no-cookware confidence level based on the resonant circuit response.

[0147] In the technical solution provided in this embodiment, the boiler detection cycle and auxiliary circuit sleep mode are incorporated into the IGBT loss state vector and target control logic. This allows for the reduction of standby auxiliary losses when there is no boiler continuously; and the restoration of detection capability by shortening the boiler detection cycle and using low-energy detection pulses when there is a possibility of boiler placement or heating triggering, thus avoiding insufficient state recognition caused by simply extending the boiler detection cycle.

[0148] Furthermore, the energy-saving control method for induction cookers based on IGBT losses may further include steps S810 and S820:

[0149] Step S810: When the current operating range is a light-load continuous heating range, compare the comprehensive loss values ​​corresponding to shortening the conduction pulse width, increasing the intermittent heating cycle, changing the valley selection sequence number, adjusting the switching frequency, and adjusting the gate drive voltage according to the target average heating power.

[0150] Step S820: When shortening the conduction pulse width causes the duration of the IGBT entering the linear region to exceed the linear region threshold, or when changing the valley selection sequence number causes the IGBT to deviate from the zero voltage turn-on window, the selection priority of the corresponding candidate control quantity combination is reduced.

[0151] In this embodiment, if the current operating range is a light-load continuous heating range, multiple candidate control quantity combinations are generated based on the target average heating power. For example, the first candidate combination is to maintain the current valley selection sequence and shorten the conduction pulse width; the second candidate combination is to maintain the conduction pulse width and increase the intermittent heating cycle; the third candidate combination is to change the valley selection sequence to turn on close to zero voltage; and the fourth candidate combination is to reduce the switching frequency and reduce the holding drive voltage. The controller predicts the values ​​of these combinations respectively. , , , , and .

[0152] If shortening the turn-on pulse width causes the IGBT to remain in the linear region for longer than the linear region threshold, the controller reduces the priority of selecting the corresponding candidate control variable combination. Understandably, an excessively short turn-on pulse width may cause the IGBT to enter the turn-off process before fully entering the saturation conduction region, resulting in simultaneously high collector-emitter voltage and collector current, leading to increased conduction and switching losses. In this case, even if the combination can reduce the average heating power, it may still cause an increase in IGBT temperature rise, and therefore should not be preferred.

[0153] If the valley selection sequence is changed to deviate the IGBT from the zero-voltage turn-on window, the controller will also reduce the selection priority of the corresponding candidate control quantity combination. Understandably, the valley selection sequence determines the position of the resonant voltage when the IGBT turns on; deviating from the zero-voltage turn-on window increases the collector voltage during turn-on, thereby increasing turn-on losses. This may reduce the soft-switching margin. If a combination meets the target average heating power but the predicted soft-switching margin is below the threshold, the combination can be directly eliminated; if it is still above the threshold but the margin is small, it can be suppressed by increasing the overall loss value or reducing the selection priority.

[0154] Specifically, the controller prioritizes comparing three combinations: "low frequency with a small number of pulse clusters," "longer intermittent periods with stable valley turn-on," and "lower holding drive voltage with saturation region hold." When the target average heating power is very low, the controller does not simply use high-power short pulses, but instead selects a combination with lower overall loss, sufficient soft-switching margin, and adequate thermal margin. This reduces losses caused by frequent switching, repeated gate charging and discharging, and non-zero voltage turn-on under light load and low power conditions.

[0155] In this way, low-power output is no longer achieved by simply shortening the conduction pulse width or increasing the interval period. Instead, the conduction pulse width, interval period, valley selection, switching frequency, and gate drive voltage are compared within the same loss evaluation framework. By reducing the priority of candidate combinations with excessively long linear region durations and deviations from the zero-voltage turn-on window, the IGBT conduction losses, switching losses, and gate drive losses can be reduced while meeting the target average heating power.

[0156] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An energy-saving control method for induction cookers based on IGBT losses, characterized in that, The energy-saving control method for induction cookers based on IGBT losses includes: Status data is collected during the current control cycle of the induction cooker. The status data includes at least the operating status of the power conversion circuit, resonant circuit, gate drive circuit, and temperature detection circuit. Based on the state data, an IGBT loss state vector is constructed. The IGBT loss state vector includes at least the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin. The current operating range is determined based on the target heating power, the cookware load status, and the IGBT loss state vector. At least two candidate control quantity combinations are generated based on the current operating range, and each candidate control quantity combination includes candidate switching timing parameters and candidate gate drive parameters; Based on the IGBT loss state vector, as well as the target heating power constraint, soft switching margin constraint, and thermal margin constraint, the target control quantity combination is determined from each of the candidate control quantity combinations. The IGBT is driven based on the target control quantity combination, and the IGBT loss state vector for the next control cycle is corrected based on the feedback data after the drive.

2. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The step of determining the current operating range based on the target heating power, the cookware load state, and the IGBT loss state vector includes: The cookware load status is determined based on the cookware detection signal, the resonant circuit response, and the user's power setting. The current operating range is determined based on the target heating power and the cookware load status; When the confidence level of no pot is higher than the threshold of no pot and no heating trigger signal is detected, the current operating range is determined to be the standby range; When it is necessary to confirm the presence, location, or material of the cookware, the current operating range is designated as the cookware inspection range. When the cookware is present and the target average heating power is lower than the low power threshold, the current operating range is determined to be a light-load continuous heating range; When a cookware is present, the target heating power is greater than or equal to the low power threshold, and the soft switching margin and the heat margin meet the corresponding thresholds, the current operating range is determined to be the normal heating range. When overvoltage, overcurrent, overtemperature, insufficient soft switching margin, or abnormal gate drive is detected, the current operating range is determined to be an abnormal protection range.

3. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The step of constructing the IGBT loss state vector based on the state data includes: The on-state loss estimate is determined based on the mapping relationship between the IGBT collector current, conduction pulse width, control period, and saturation voltage drop corresponding to the current gate drive voltage. The estimated switching loss is determined based on the collector voltage before IGBT turn-on, collector current at turn-off, switching frequency, gate drive voltage, equivalent gate resistance, estimated junction temperature, and soft switching margin. The gate drive loss estimate is determined based on the gate charge, gate drive voltage, switching frequency, and gate drive circuit efficiency. The estimated standby auxiliary loss is determined based on the wake-up duty cycle and static current of the gate driver chip, sampling circuit, synchronization detection circuit, display circuit, or communication circuit within the standby interval. The IGBT loss state vector is generated based on the on-state loss estimate, the switching loss estimate, the gate drive loss estimate, the standby auxiliary loss estimate, the soft switching margin, and the thermal margin.

4. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The step of generating at least two candidate control quantity combinations based on the current operating range includes: Within the parameter range corresponding to the current operating interval, candidate switch timing parameters are generated. The candidate switch timing parameters include at least four of the following: synchronization edge advance, synchronization edge lag, valley selection sequence number, conduction pulse width, turn-off window, switching frequency, number of pulse clusters, intermittent heating cycle, boiler detection cycle, and low-energy detection pulse width. Within the gate drive range corresponding to the current operating interval, candidate gate drive parameters are generated. The candidate gate drive parameters include at least three of the following: pre-drive voltage, turn-on drive voltage, hold drive voltage, turn-off drive voltage, turn-on drive current, turn-off drive current, equivalent gate resistance, pre-drive duration, and drive voltage switching time. The candidate switch timing parameters and the candidate gate drive parameters are combined to obtain at least two combinations of the candidate control quantities.

5. The energy-saving control method for induction cookers based on IGBT losses as described in claim 4, characterized in that, The step of determining the target control quantity combination from each of the candidate control quantity combinations based on the IGBT loss state vector, as well as the target heating power constraint, soft switching margin constraint, and thermal margin constraint, includes: For each candidate control quantity combination, predict the predicted heating energy deviation, predicted soft switching margin, predicted thermal margin, and overall loss value respectively. Candidate control quantity combinations that are excluded include those where the predicted heating energy deviation exceeds the corresponding power deviation threshold, the predicted soft switching margin is lower than the corresponding soft switching margin threshold, and the predicted thermal margin is lower than the corresponding thermal margin threshold. From the remaining candidate control variable combinations, the target control variable combination is determined based on the comprehensive loss value and preset selection conditions.

6. The energy-saving control method for induction cookers based on IGBT losses as described in claim 5, characterized in that, The overall loss value is determined according to an objective function, which is: ； in, This is the estimate of the on-state loss. For the estimation of commissioning losses, This is an estimate of the turn-off loss. This is the estimate of the gate drive loss. This is the estimated amount of standby auxiliary loss. As a thermal risk item, The target heating energy deviation term, to The weight corresponding to the current operating interval.

7. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The step of driving the IGBT based on the target control quantity combination includes: During the pre-discharge phase before IGBT turn-on, the IGBT is driven based on the pre-drive voltage and pre-drive duration in the target control quantity combination. When the load current, resonant voltage, or conduction pulse width meets the preset switching conditions, the switch is made to the turn-on drive voltage in the target control quantity combination. During the light load holding phase, the IGBT is kept on according to the holding drive voltage or equivalent gate resistance in the target control quantity combination.

8. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The step of correcting the IGBT loss state vector for the next control cycle based on the feedback data after driving includes: The feedback data is determined based on the heat sink temperature, ambient temperature, peak IGBT collector voltage, peak IGBT collector current, and soft-switching margin after the drive. Based on the thermal resistance and thermal capacity model and the IGBT loss state vector in the current control cycle, the IGBT junction temperature is estimated. Based on the residual between the estimated temperature rise and the measured temperature rise, correct the saturation voltage drop mapping, switching energy mapping, gate drive loss coefficient, and / or the loss weight corresponding to the current operating range.

9. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The energy-saving control method for induction cookers based on IGBT losses also includes: When the current operating interval is a standby interval or a boiler detection interval, the boiler detection cycle is determined based on the no-boiler confidence, the most recent boiler detection response, and the standby auxiliary loss estimate. When the no-boiler status is continuously confirmed, at least one of the gate drive circuit, sampling circuit, or synchronous detection circuit is controlled to enter sleep mode. When the confidence level of no pot decreases or a heating trigger signal is detected, the pot detection cycle is shortened, and a low-energy detection pulse is generated based on a short conduction pulse width, a low pre-drive voltage, and a predetermined valley trigger window.

10. The energy-saving control method for induction cookers based on IGBT losses as described in claim 1, characterized in that, The energy-saving control method for induction cookers based on IGBT losses also includes: When the current operating range is a light-load continuous heating range, the comprehensive loss value corresponding to shortening the conduction pulse width, increasing the intermittent heating cycle, changing the valley selection sequence, adjusting the switching frequency, and adjusting the gate drive voltage is compared based on the target average heating power. When shortening the conduction pulse width causes the duration of the IGBT entering the linear region to exceed the linear region threshold, or when changing the valley selection sequence causes the IGBT to deviate from the zero-voltage turn-on window, the selection priority of the corresponding candidate control quantity combination is reduced.

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