Control circuit, control method thereof, and electromagnetic range

Abstract

The application discloses a control circuit, a control method thereof and an electromagnetic range. The control circuit comprises a resonant heating module, a driving power tube, a control module, a driving module and a low-frequency and high-frequency current detection module. The low-frequency current detection module is used for detecting the low-frequency current when the driving power tube is turned on in real time; the high-frequency current detection module is used for detecting the high-frequency current when the driving power tube is turned on in real time; the control module is used for calculating the difference between the low-frequency current and the high-frequency current, judging whether the driving power tube corresponding to the resonant heating module will be in a hard-on state or a freewheeling state according to the size of the difference and outputting a pulse control signal; and the driving module is used for receiving the pulse control signal and controlling the turn-on time of the driving power tube according to the pulse control signal, so as to control the heating power of the resonant heating module. The control circuit of the application can determine whether the power tube will be in the hard-on state or the freewheeling state by detecting the high-frequency current and the low-frequency current of electromagnetic induction heating, control the turn-on time of the driving power tube and play a role in protecting the power tube.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic cooker technology, and in particular to a control circuit and its control method, and an electromagnetic cooker. Background Technology

[0002] An induction cooker is an electric cooking appliance that uses the principle of electromagnetic induction heating. It generates an alternating magnetic field through a high-frequency induction heating coil (i.e., an excitation coil), which induces eddy currents in a metal pot placed on the cooktop, thus heating the food. Induction cookers are widely used due to their advantages such as high efficiency and energy saving, ease of control, and wide applicability.

[0003] Currently, the control technology in electromagnetic heating control circuits can employ a single-transistor topology to control the coil heating of cookware. However, this single-transistor topology has several drawbacks. For example, when the coil operates at continuous low power, the insulated gate bipolar transistor (IGBT) exhibits a hard-turn-on phenomenon. This means the IGBT turns on at a higher voltage before resonating at its zero-crossing point, leading to excessive instantaneous current during IGBT turn-on, resulting in excessive IGBT switching losses, high IGBT temperature rise, and even breakdown damage. Another example is when the coil operates at high power. The freewheeling current generated by the internal body diode of the IGBT during turn-off can cause rapid temperature rise or overvoltage stress, leading to IGBT damage. Summary of the Invention

[0004] In view of this, the present invention aims to at least partially solve one of the problems in the related art. Therefore, the object of the present invention is to provide a control circuit and its control method, and an induction cooker.

[0005] This application provides a control circuit. The control circuit includes a resonant heating module, a driving power transistor, a control module, a driving module, a low-frequency current detection module, and a high-frequency current detection module. The input terminal of the low-frequency current detection module is connected to a first terminal of the resonant heating module, and the output terminal of the low-frequency current detection module is connected to the input terminal of the control module. The second terminal of the resonant heating module is connected to the collector of the driving power transistor. The emitter of the driving power transistor is connected to the first terminal of the high-frequency current detection module. The output terminal of the high-frequency current detection module is connected to the input terminal of the control module. The second terminal of the high-frequency current detection module is grounded. The output terminal of the control module is connected to the input terminal of the driving module. The gate of the power transistor is connected to the output terminal of the driving module; the resonant heating module is used to heat the cookware; the low-frequency current detection module is used to detect the low-frequency current when the driving power transistor is turned on in real time; the high-frequency current detection module is used to detect the high-frequency current when the driving power transistor is turned on in real time; the control module is used to calculate the difference between the low-frequency current and the high-frequency current, and determine whether the driving power transistor corresponding to the resonant heating module will be in a hard-on state or a freewheeling state based on the magnitude of the difference, so as to output a pulse control signal; the driving module is used to receive the pulse control signal, and control the conduction time of the driving power transistor according to the pulse control signal, so as to control the heating power of the resonant heating module.

[0006] In some embodiments, the control module is used to: if the difference is greater than a preset threshold, determine that the driving power transistor corresponding to the resonant heating module is in a freewheeling state, and control to reduce the duty cycle of the pulse control signal received by the driving power transistor to reduce the conduction time of the driving power transistor, thereby reducing the heating power of the resonant heating module.

[0007] In some embodiments, the control module is configured to: calculate the hard-on current of the driving power transistor when the resonant heating module operates at a power lower than a predetermined power threshold, based on the low-frequency current, the high-frequency current, and the amplification factor of the low-frequency current detection module and the high-frequency current detection module; if the hard-on current is greater than the hard-on current threshold, determine that the driving power transistor corresponding to the resonant heating module will be in a hard-on state, control the increase of the duty cycle of the pulse control signal received by the driving power transistor to increase the conduction time of the driving power transistor, thereby controlling the increase of the heating power of the resonant heating module, so that the resonant heating module operates within a preset power range.

[0008] In some embodiments, the control circuit includes multiple resonant heating modules, multiple drive power transistors connected to the resonant heating modules, multiple drive modules, and multiple high-frequency current detection modules, wherein the multiple resonant heating modules are connected in parallel; the control module is used to: calculate the difference between the low-frequency current and the high-frequency current of the multiple resonant heating modules respectively; and determine whether the multiple drive power transistors corresponding to the multiple resonant heating modules are in a hard-on state or a freewheeling state based on the magnitude of the difference in order to output the pulse control signal.

[0009] In some embodiments, the control module is configured to: if the difference between the low-frequency current and the high-frequency current corresponding to at least one of the resonant heating modules exceeds a preset threshold, determine that the driving power transistor corresponding to the resonant heating module will be in a freewheeling state, control the reduction of the duty cycle of the pulse control signal received by the corresponding at least one of the driving power transistors to reduce the conduction time of the at least one of the driving power transistors, and reduce the heating power of the at least one of the resonant heating modules so that the at least one of the resonant heating modules operates within a preset power range.

[0010] In some embodiments, the control module is configured to: calculate the hard-on current of the multiple driving power transistors when the multiple resonant heating modules operate at a power lower than a predetermined power threshold, based on the low-frequency current, the multiple high-frequency currents, and the amplification factor of the low-frequency current detection module and the amplification factor of the high-frequency current detection module; if at least one of the hard-on currents is greater than the hard-on current threshold, determine that the driving power transistor corresponding to at least one of the resonant heating modules will be in a hard-on state, control to increase the duty cycle of the pulse control signal received by at least one of the driving power transistors to increase the conduction time of at least one of the driving power transistors, and control to increase the heating power corresponding to at least one of the resonant heating modules, so that at least one of the resonant heating modules operates within a preset power range.

[0011] In some embodiments, the low-frequency current detection module includes a first resistor and a low-frequency current amplification module connected in parallel with the first resistor. The first resistor is connected to a first terminal of the resonant heating module. The output terminal of the low-frequency current amplification module is connected to the input terminal of the control module. The first resistor is used to acquire an initial low-frequency current. The low-frequency current amplification module is used to amplify the initial low-frequency current to obtain the low-frequency current.

[0012] In some embodiments, the high-frequency current detection module includes a second resistor and a high-frequency current amplification module connected in parallel with the second resistor. The first end of the second resistor is connected to the emitter of the driving power transistor, and the second end of the second resistor is grounded. The output end of the high-frequency current amplification module is connected to the input end of the control module. The second resistor is used to acquire an initial high-frequency current. The high-frequency current amplification module is used to amplify the initial high-frequency current to obtain the high-frequency current.

[0013] In some embodiments, the control module is further configured to: if there is a difference between the low-frequency current and the high-frequency current and the difference is greater than a preset threshold, or the difference between the low-frequency current at the previous moment and the low-frequency current at the current moment is greater than a preset threshold, or the difference between the high-frequency current at the previous moment and the high-frequency current at the current moment is greater than a preset threshold, control the re-detection of the low-frequency current and the high-frequency current, and re-determine, based on the difference between the low-frequency current and the high-frequency current, whether the drive power transistor corresponding to the resonant heating module for heating the current cookware will be in a hard-on state or a freewheeling state to output the pulse control signal.

[0014] In some embodiments, the control circuit further includes a power supply module, a first filter module, a rectifier module, and a second filter module. The input terminal of the first filter module is connected to the power supply module, the first output terminal of the first filter module is connected to the input terminal of the rectifier module, and the second output terminal of the first filter module is connected to the control module. The first output terminal of the rectifier module is connected to the first input terminal of the second filter module, and the second output terminal of the rectifier module is connected to the second input terminal of the second filter module through the low-frequency current detection module. The output terminal of the second filter module is connected to the first terminal of the resonant heating module. The power supply module provides electrical energy. The first filter module filters the AC signal emitted by the power supply module. The rectifier module converts the AC signal after filtering by the first filter module into a DC signal. The second filter module filters the DC signal after processing by the rectifier module.

[0015] This application also provides an electromagnetic cooker. The electromagnetic cooker includes the control circuit described in any of the above embodiments.

[0016] This application also provides a control method for the control circuit described in any of the above embodiments. The control method includes: real-time detection of the low-frequency current when the driving power transistor is turned on; real-time detection of the high-frequency current when the driving power transistor is turned on; calculation of the difference between the low-frequency current and the high-frequency current, determining whether the driving power transistor corresponding to the resonant heating module will be in a hard-on state or a freewheeling state based on the magnitude of the difference to output a pulse control signal; receiving the pulse control signal, and controlling the conduction time of the driving power transistor according to the pulse control signal to control the heating power of the resonant heating module.

[0017] Thus, the control circuit of this application determines whether the drive power transistor connected to the resonant heating module is in a hard-on state or a freewheeling state by real-time detection of the high-frequency and low-frequency currents of electromagnetic induction heating. Based on different states, it controls the conduction time of the drive power transistor to increase or decrease, thereby controlling the heating power of the resonant heating module to increase or decrease, thereby protecting the drive power transistor.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 This is a schematic diagram of the control circuit structure in some embodiments of this application;

[0021] Figure 2 This is a partial structural schematic diagram of the control circuit in some embodiments of this application;

[0022] Figure 3 This is a schematic diagram of the low-frequency current amplification module in the control circuit of some embodiments of this application;

[0023] Figure 4 This is a schematic diagram of the structure of the high-frequency current amplification module in the control circuit of some embodiments of this application;

[0024] Figure 5 This is a partial structural diagram of a control circuit with multiple resonant heating modules in certain embodiments of this application;

[0025] Figure 6 This is a schematic diagram of the structure of a low-frequency current amplification module in the control circuit of certain embodiments of this application when multiple resonant heating modules are included;

[0026] Figure 7This is a schematic diagram of the structure of the first high-frequency current amplification module in the control circuit of certain embodiments of this application when it has multiple resonant heating modules;

[0027] Figure 8 This is a schematic diagram of the structure of the second high-frequency current amplification module in the control circuit of certain embodiments of this application when multiple resonant heating modules are included.

[0028] Main component reference numerals:

[0029] Control circuit 100;

[0030] The system includes: a resonant heating module 10, a first resonant heating module 11, a second resonant heating module 12; a drive power transistor 20, a first drive power transistor 21, a second drive power transistor 22; a control module 30; a drive module 40; a current detection module 50, a low-frequency current detection module 51, a low-frequency current amplification module 511, a comparator amplifier 5111 for the low-frequency current amplification module, a high-frequency current detection module 52, a high-frequency current amplification module 5213, a first high-frequency current amplification module 5211, a comparator amplifier 52111 for the first high-frequency current amplification module, a second high-frequency current amplification module 52121, and a comparator amplifier 52121 for the second high-frequency current amplification module; a power supply module 60; a first filter module 70; a rectifier module 80; a second filter module 90; a first resistor R1 and a second resistor R2. Detailed Implementation

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0032] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation" and "connection" should be interpreted broadly, referring to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections, or connections that allow communication between components; direct connections or indirect connections via an intermediate medium; and connections within two components or interactions between two components. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0034] The following disclosure provides many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0035] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0036] Please see Figure 1 This application discloses a control circuit 100. The control circuit 100 includes a resonant heating module 10, a drive power transistor 20, a control module 30, a drive module 40, a low-frequency current detection module 51, and a high-frequency current detection module 52.

[0037] The resonant heating module 10 is used to heat cookware. The resonant heating module 10 includes a resonant capacitor C and a coil inductance L.

[0038] The emitter (E) of the drive power transistor 20 is connected to the first terminal of the high-frequency current detection module 52. The second terminal of the high-frequency current detection module 52 is grounded.

[0039] The input terminal of the low-frequency current detection module 51 is connected to the first terminal of the resonant heating module 10, and the output terminal of the low-frequency current detection module 51 is connected to the input terminal of the control module 30. The low-frequency current detection module 51 is used to detect the low-frequency current when the drive power transistor 20 is turned on in real time.

[0040] The output terminal of the high-frequency current detection module 52 is connected to the input terminal of the control module 30. The high-frequency current detection module 52 is used to detect the high-frequency current when the drive power transistor 20 is turned on in real time.

[0041] The output terminal of the control module 30 is connected to the input terminal of the drive module 40, and the gate (G) of the drive power transistor 20 is connected to the output terminal of the drive module 40. The control module 30 is used to calculate the difference between the low-frequency current and the high-frequency current, and determines whether the drive power transistor corresponding to the resonant heating module will be in a hard-on state or a freewheeling state based on the magnitude of the difference, so as to output a pulse control signal.

[0042] Understandably, low-frequency current is as follows: Figure 2 The diagram shows a resonant heating module 10, a drive power transistor 20, and a high-frequency current detection module 52. Figure 2 The image only shows the second resistor R2 and the low-frequency current detection module 51. Figure 2 The image only shows the current value formed within the low-frequency circuit formed by the first resistor (R1). The high-frequency current is as follows: Figure 2 The diagram shows a resonant heating module 10, a drive power transistor 20, and a high-frequency current detection module 52. Figure 2 The image only shows the current value formed in the high-frequency circuit formed by the second resistor R2.

[0043] The drive module 40 is used to receive pulse control signals and control the conduction time of the drive power transistor 20 according to the pulse control signals, so as to control the heating power of the resonant heating module 10.

[0044] That is, the control circuit 100 of this application adds a low-frequency current detection module 51 and a high-frequency current detection module 52. The low-frequency current detection module 51 detects the low-frequency current of electromagnetic induction heating in real time, and the high-frequency current detection module 52 detects the high-frequency current of electromagnetic induction heating in real time. Then, the control module 30 calculates the difference between the low-frequency current and the high-frequency current to determine whether the drive power transistor 20 connected to the resonant heating module 10 is in a hard-on state or a freewheeling state, thereby outputting different pulse control signals to the drive module 40. This allows the drive module 40 to control the conduction time of the drive power transistor 20 according to the pulse control signal, thereby controlling the heating power of the resonant heating module 10 and protecting the drive power transistor.

[0045] Thus, the control circuit 100 of this application determines whether the drive power transistor 20 connected to the resonant heating module 10 is in a hard-on state or a freewheeling state by real-time detection of the high-frequency current and low-frequency current of electromagnetic induction heating. Based on different states, it controls the conduction time of the drive power transistor 20 to increase or decrease, thereby controlling the heating power of the resonant heating module 10 to increase or decrease, thereby protecting the drive power transistor 20.

[0046] Please see Figure 1 and Figure 2 The control circuit 100 of this application may further include a power supply module 60, a first filter module 70, a rectifier module 80, and a second filter module 90.

[0047] The power module 60 is used to provide electrical energy.

[0048] The input terminal of the first filtering module 70 is connected to the power supply module 60, the first output terminal of the first filtering module 70 is connected to the input terminal of the rectifier module 80, and the second output terminal of the first filtering module 70 is connected to the control module 30. The first filtering module 70 is used to filter the AC signal emitted by the power supply module 60.

[0049] The first output terminal of the rectifier module 80 is connected to the first input terminal of the second filter module 90, and the second output terminal of the rectifier module 80 is connected to the second input terminal of the second filter module 90 through the low-frequency current detection module 51. The rectifier module 80 is used to convert the AC signal after filtering by the first filter module 70 into a DC signal.

[0050] The output terminal of the second filter module 90 is connected to the first terminal of the resonant heating module 10. The second terminal of the resonant heating module 10 is connected to the collector (C) of the driving power transistor 20. The second filter module 90 is used to filter the DC signal processed by the rectifier module 80.

[0051] In addition, since the drive module 40 of this application can control the conduction time of the drive power tube 20 according to the pulse control signal, and thus control the heating power of the resonant heating module 10, the control circuit 100 of this application can also calibrate the heating power value of the resonant heating module 10 in the circuit by the difference between the low-frequency current and the high-frequency current, so that the resonant heating module 10 operates within the safe power range.

[0052] Furthermore, the control circuit 100 of this application may also include a zero-crossing detection module, a voltage detection module, and a power supply module, and their connection relationships are as follows: Figure 1 As shown, the input terminal of the zero-crossing detection module is connected to the first output terminal of the first filter module 70 and the power supply module', and the output terminal of the zero-crossing detection module is connected to the control module 30. The zero-crossing detection module generates a signal when the voltage or current waveform of the AC power crosses zero, so as to control and protect the control circuit 100. The input terminal of the voltage detection module is connected to the first output terminal of the first filter module 70 and the power supply module, and the output terminal of the voltage detection module is connected to the control module 30. The voltage detection module is used to detect the voltage of the control circuit 100. The power supply module' provides startup power for the zero-crossing detection module, the voltage detection module, and the control module 30.

[0053] Please refer to the following: Figures 1 to 4In some embodiments, the control circuit 100 includes a resonant heating module 10. The control module 30 is used to: if the difference is greater than a preset threshold, determine that the driving power transistor 20 corresponding to the resonant heating module 10 will be in a freewheeling state, and control to reduce the duty cycle of the pulse control signal received by the driving power transistor 20 to reduce the conduction time of the driving power transistor 20, thereby reducing the heating power of the resonant heating module 10.

[0054] Understandably, the duty cycle of a pulse control signal refers to the ratio of the time the pulse control signal is at a high level (or effective level) to the total cycle time within one period. When controlling the drive power transistor 20, the duty cycle of the pulse control signal directly determines the conduction time of the drive power transistor 20 in each cycle. When the duty cycle decreases, the conduction time of the drive power transistor 20 decreases, thereby reducing the product of the current and voltage through the drive power transistor 20, i.e., the power, and thus reducing the heating power or output power of the resonant heating module 10.

[0055] Specifically, the preset threshold can be a value determined through experiments. Furthermore, for different models and power induction cookers, the resonant capacitance and coil inductance of the resonant heating module 10 will vary, directly affecting the range and characteristics of low-frequency and high-frequency currents. Therefore, the preset threshold can be set according to the specific characteristics of the device.

[0056] When the difference between the low-frequency current and the high-frequency current exceeds a preset threshold, the control circuit 100 of this application indicates that the drive power transistor 20 will be in a freewheeling state, and the freewheeling current of the drive power transistor 20 is large. Therefore, at this time, it is necessary to reduce the power to reduce the freewheeling current value of the drive power transistor 20, thereby protecting the drive power transistor 20 from damage.

[0057] Correspondingly, the control circuit 100 of this application can control the reduction of the duty cycle of the pulse control signal received by the drive power transistor 20 through the control module 30, thereby reducing the conduction time of the drive power transistor 20 and reducing the heating power of the resonant heating module 10, thus protecting the drive power transistor 20 from damage when it is in the freewheeling state.

[0058] In some embodiments, when the amplification factor of the low-frequency current detection module 51 is different from that of the high-frequency current detection module 52, the control module 30 is used to: calculate the hard-on current of the drive power transistor 20 when the resonant heating module 10 is operating at a power lower than a predetermined power threshold, based on the low-frequency current, the high-frequency current, and the amplification factors of the low-frequency current detection module 51 and the high-frequency current detection module 52; if the hard-on current is greater than the hard-on current threshold, it is determined that the drive power transistor 20 corresponding to the resonant heating module 10 will be in a hard-on state, and the duty cycle of the pulse control signal received by the drive power transistor 20 is increased to increase the conduction time of the drive power transistor 20, so as to control and increase the heating power of the resonant heating module 10, so that the resonant heating module 10 operates within a preset power range.

[0059] Understandably, the resonant heating module 10 operates at a power level below a predetermined power threshold, that is, the resonant heating module heats the cookware at a low power. For example, the predetermined power threshold can be 10W, 11W, 12W, 13W, 14W, 15W, 16W, 17W, 18W, 19W, and 20W, and is not limited here.

[0060] The hard-start current threshold can refer to the critical current difference between the high-frequency current and the low-frequency current at which the drive power transistor 20 will hard-start when the resonant heating module 10 is operating at low power.

[0061] Specifically, based on the low-frequency current, high-frequency current, and the amplification factors of the low-frequency current detection module 51 and the high-frequency current detection module 52, the hard-on threshold of the driving power transistor 20 when the resonant heating module 10 operates within the first power range is calculated. That is, if the low-frequency current is I1, the high-frequency current is I2, the amplification factor of the low-frequency current detection module 51 is K1, and the amplification factor of the high-frequency current detection module 52 is K2, then the hard-on current can be |I1-0.5(K1 / K2)I2|. If the hard-on current threshold is 0A, then when the difference between the low-frequency current I1 and 0.5(K1 / K2) times the high-frequency current I2 is greater than 0, it indicates that the driving power transistor 20 corresponding to the resonant heating module 10 will be in a hard-on state. When the difference between the low-frequency current I1 and 0.5(K1 / K2) times the high-frequency current I2 is equal to 0, it indicates that the driving power transistor 20 corresponding to the resonant heating module 10 is not in a hard-on state.

[0062] For example, when K1 = 2, K2 = 3, I1 = 2A, I2 = 3A, then |I1-0.5(K1 / K2)I2 = 1A| > 0, which means that the drive power transistor 20 corresponding to the resonant heating module 10 will be in a hard-on state.

[0063] When it is determined that the drive power transistor 20 corresponding to the resonant heating module 10 will be in a hard-on state, the control module 30 can control the increase of the duty cycle of the pulse control signal received by the drive power transistor 20 to increase the conduction time of the drive power transistor 20, thereby controlling and increasing the heating power of the resonant heating module 10, so that the resonant heating module 10 operates within a preset power range. The preset power range is the power range within which the resonant heating module 10 can operate safely, preventing the hard-on phenomenon during low-power operation from causing excessive instantaneous current in the drive power transistor 20 and resulting in damage.

[0064] Thus, the control module 30 of the control circuit 100 of this application can calculate the hard-open current based on the low-frequency current, high-frequency current, the amplification factor of the low-frequency current detection module 51 and the amplification factor of the high-frequency current detection module 52. It can then determine whether the drive power transistor 20 will be in a hard-open state based on the hard-open current threshold. Furthermore, when the resonant heating module 10 is operating at low power and the drive power transistor 20 will be in a hard-open state, the duty cycle of the pulse control signal received by the drive power transistor 20 is increased to improve the heating power of the resonant heating module 10. This can prevent the drive power transistor 20 from being damaged due to excessive current at the moment of conduction, thereby protecting the drive power transistor 20.

[0065] In some embodiments, the control circuit 100 may further include multiple resonant heating modules 10, multiple drive power transistors 20 connected to the resonant heating modules 10, multiple drive modules 40, and multiple high-frequency current detection modules 52, with the multiple resonant heating modules 10 connected in parallel. The control module 30 is used to: calculate the difference between the low-frequency current and the high-frequency current of the multiple resonant heating modules 10 respectively; and determine, based on the magnitude of the difference, whether the multiple drive power transistors 20 corresponding to the multiple resonant heating modules 10 will be in a hard-on state or a freewheeling state to output a pulse control signal.

[0066] In one embodiment, the control circuit 100 includes two resonant heating modules 10, namely a first resonant heating module 11 and a second resonant heating module 12. Correspondingly, the control circuit 100 has a first driving power transistor 21, a first driving module, and a first high-frequency current detection module connected to the first resonant heating module 11, and a second driving power transistor 22, a second driving module, and a second high-frequency current detection module connected to the second resonant heating module 12.

[0067] In other words, the control module 30 of this application can calculate the first difference A of the current between the first high-frequency current detection module and the low-frequency current detection module 51, and the second difference B of the current between the first high-frequency current detection module and the low-frequency current detection module 51, respectively, for the first resonant heating module 11 and the second resonant heating module 12. That is, it calculates the difference between the low-frequency current and the high-frequency current of the multiple resonant heating modules 10. Then, it determines the magnitude of the first difference A and the second difference B, thereby determining whether the first driving power transistor 21 corresponding to the first resonant heating module 11 and the second driving power transistor 22 corresponding to the second resonant heating module 12 will be in a hard-on state or a freewheeling state. This allows the control module 30 to output a pulse control signal to control the conduction time of the first driving power transistor 21 and the second driving power transistor 22, thereby controlling the heating power of the first resonant heating module 11 and the second resonant heating module 12.

[0068] Therefore, the control module 30 of this application can avoid the problem of power transistors being damaged due to hard-opening phenomenon of the first driving power transistor 21 and the second driving power transistor 22 by controlling the conduction time of the first driving power transistor 21 and the second driving power transistor 22. It can also avoid the problem of the power transistors being damaged due to rapid temperature rise or overpressure stress when the first driving power transistor 21 and the second driving power transistor 22 are in freewheeling state.

[0069] It should be noted that if the difference between the low-frequency current and the high-frequency current of only one of the multiple resonant heating modules 10 is determined to be such that the corresponding driving power transistor 20 will be in a hard-on state or a freewheeling state, then only the conduction time of the corresponding driving power transistor 20 is controlled, so as to avoid the driving power transistor 20 from being damaged due to hard-on phenomenon, and to avoid the driving power transistor 20 from being damaged due to the large freewheeling current of the driving power transistor 20 in the freewheeling state.

[0070] If the difference between the low-frequency current and the high-frequency current of multiple resonant heating modules 10 is determined to indicate that the corresponding multiple driving power transistors 20 will be in a hard-on state or a freewheeling state, then only the conduction time of the corresponding multiple driving power transistors 20 is controlled to avoid damage caused by the hard-on phenomenon of multiple driving power transistors 20, and to avoid damage caused by the large freewheeling current of multiple driving power transistors 20 in the freewheeling state.

[0071] Thus, the control circuit 100 of this application can not only control the conduction time of the drive power transistor 20 corresponding to one resonant heating module 10, but also control the conduction time of multiple drive power transistors 20 corresponding to multiple resonant heating modules 10, so as to avoid the multiple drive power transistors 20 from being damaged due to hard-opening, and to avoid the multiple drive power transistors 20 from being damaged due to the large freewheeling current of the drive power transistors 20 in the freewheeling state.

[0072] In some embodiments, the control module 30 is configured to: if the difference between the low-frequency current and the high-frequency current corresponding to at least one resonant heating module 10 exceeds a preset threshold, determine that the driving power transistor 20 corresponding to the resonant heating module 10 is in a freewheeling state, control the reduction of the duty cycle of the pulse control signal received by the corresponding at least one driving power transistor 20 to reduce the conduction time of the at least one driving power transistor 20, and reduce the heating power of the at least one resonant heating module 10 so that the at least one resonant heating module 10 operates within a preset power range.

[0073] Understandably, the duty cycle of a pulse control signal refers to the ratio of the time the pulse control signal is at a high level (or effective level) to the total cycle time within one period. When controlling the drive power transistor 20, the duty cycle of the pulse control signal directly determines the conduction time of the drive power transistor 20 in each cycle. When the duty cycle decreases, the conduction time of the drive power transistor 20 decreases, thereby reducing the product of the current and voltage through the drive power transistor 20, i.e., the power, and thus reducing the heating power or output power of the resonant heating module 10.

[0074] Specifically, the preset threshold can be a value determined experimentally. Furthermore, different models and power induction cookers will have different parameters such as the resonant capacitance and coil inductance of their resonant heating modules, which directly affects the variation range and characteristics of low-frequency and high-frequency currents. Therefore, the preset threshold can be set according to the specific characteristics of the device.

[0075] When the control circuit 100 of this application has multiple resonant heating modules 10, if the difference between the low-frequency current and the high-frequency current corresponding to any one or more resonant heating modules 10 exceeds a preset threshold, it indicates that one or more corresponding drive power transistors 20 will be in a freewheeling state, and the freewheeling current of the drive power transistors 20 is large. Therefore, at this time, it is necessary to reduce the power to protect one or more drive power transistors 20 from being damaged.

[0076] Correspondingly, the control circuit 100 of this application can control the reduction of the duty cycle of the pulse control signal received by one or more drive power transistors 20 through the control module 30, thereby reducing the conduction time of one or more drive power transistors 20, and thus reducing the heating power of one or more resonant heating modules 10, thereby protecting one or more drive power transistors 20 from damage when they are in freewheeling state.

[0077] In some embodiments, when the amplification factor of the low-frequency current detection module 51 is different from that of the high-frequency current detection module 52, the control module 30 is used to: calculate the hard-on current of the multiple driving power transistors 20 when the multiple resonant heating modules 10 are operating at a power lower than a predetermined power threshold, based on the low-frequency current, multiple high-frequency currents, and the amplification factors of the low-frequency current detection module 51 and the high-frequency current detection module 52; if at least one hard-on current is greater than or equal to the hard-on current threshold, it is determined that the driving power transistor 20 corresponding to at least one resonant heating module 10 is in a hard-on state, and the duty cycle of the pulse control signal received by at least one driving power transistor 20 is increased to increase the conduction time of at least one driving power transistor 20, and the heating power of the corresponding at least one resonant heating module 10 is increased so that at least one resonant heating module 10 operates within a preset power range.

[0078] Understandably, the resonant heating module 10 operates at a power level below a predetermined power threshold, that is, the resonant heating module heats the cookware at a low power. For example, the predetermined power threshold can be 10W, 11W, 12W, 13W, 14W, 15W, 16W, 17W, 18W, 19W, and 20W, and is not limited here.

[0079] The hard-open current threshold can refer to the critical current difference between the high-frequency current and the low-frequency current that will cause the driving power transistor 20 to hard-open when the resonant heating module 10 is operating at low power.

[0080] Specifically, for example, if the plurality of resonant heating modules 10 includes two, namely a first resonant heating module 11 and a second resonant heating module 12, then the control circuit 100 has a first driving power transistor 21, a first driving module, and a first high-frequency current detection module connected to the first resonant heating module 11, and a second driving power transistor 22, a second driving module, and a second high-frequency current detection module connected to the second resonant heating module 12.

[0081] Based on the low-frequency current, high-frequency current, and the amplification factors of the low-frequency current detection module 51 and the high-frequency current detection module 52, the hard-on current of the multiple driving power transistors 20 when the multiple resonant heating modules 10 are operating within the first power range is calculated. That is, if the first low-frequency current is I1, the first high-frequency current is I2, the amplification factor of the low-frequency current detection module 51 is KA1, and the amplification factor of the first high-frequency current detection module is KA2, then the hard-on current of the first driving power transistor 21 can be |I1-0.5(KA1 / KA2)I2|. If the hard-on current threshold is 0A, then when the difference between the first low-frequency current I1 and 0.5(KA1 / KA2) times the first high-frequency current I2 is greater than 0, it indicates that the first driving power transistor 21 corresponding to the first resonant heating module 11 will be in a hard-on state. For example, when KA1 = 2, KA2 = 4, I1 = 2A, and I2 = 3A, then |I1 - 0.5(K1 / K2)I2 = 1.25A| > 0, indicating that the first driving power transistor 21 corresponding to the first resonant heating module 11 will be in a hard-on state. When the difference between the low-frequency current I1 and 0.5(KA1 / KA2) times the first high-frequency current I2 equals 0, it indicates that the driving power transistor 20 corresponding to the resonant heating module 10 is not in a hard-on state.

[0082] When it is determined that at least one drive power transistor 20 corresponding to at least one resonant heating module 10 will be in a hard-on state, the control module 30 can control the increase of the duty cycle of the pulse control signal received by the corresponding at least one drive power transistor 20 to increase the conduction time of the at least one drive power transistor 20, thereby controlling the increase of the heating power of the at least one resonant heating module 10, so that the at least one resonant heating module 10 operates within a preset power range. The preset power range is the power range within which the resonant heating module 10 can operate safely, preventing the hard-on phenomenon during low-power operation from causing excessive instantaneous current in the drive power transistor 20 and resulting in damage.

[0083] Thus, the control module 30 of the control circuit 100 of this application can calculate the hard-on current of the multiple driving power transistors when the multiple resonant heating modules operate at a power lower than a predetermined power threshold based on the low-frequency current, high-frequency current, the amplification factor of the low-frequency current detection module 51 and the amplification factor of the high-frequency current detection module 52. Therefore, it can determine whether the multiple driving power transistors 20 will be in a hard-on state based on the hard-on current threshold. Then, when at least one resonant heating module 10 is operating at low power and at least one driving power transistor 20 will be in a hard-on state, the duty cycle of the pulse control signal received by at least one driving power transistor 20 is increased to improve the heating power of at least one resonant heating module 10. This can prevent at least one driving power transistor 20 from being damaged due to excessive current at the moment of conduction, thereby protecting the driving power transistor 20.

[0084] Please see Figure 2 and Figure 3 In some embodiments, the low-frequency current detection module 51 includes a first resistor R1 and a low-frequency current amplification module 511 connected in parallel with the first resistor R1. The first resistor R1 is connected to the first terminal of the resonant heating module 10 and is used to acquire the initial low-frequency current. When the control circuit 100 includes a rectifier module 80 and a second filter module 90, the first terminal of the first resistor R1 is connected to the output terminal of the rectifier module 80, and the second terminal of the first resistor R1 is connected to the input terminal of the second filter module 90.

[0085] The output terminal of the low-frequency current amplification module 511 is connected to the input terminal of the control module 30. The low-frequency current amplification module 511 is used to amplify the initial low-frequency current to obtain a lower-frequency current.

[0086] The internal circuit structure of the low-frequency current amplifier module 511 is as follows: Figure 3 As shown. The first input terminal CUR0 of the low-frequency current amplifier module 511 is connected to... Figure 2 At the CUR0 mark shown, the second input terminal CUR1 of the low-frequency current amplifier module 511 is connected to... Figure 2 The low-frequency current output of the low-frequency current amplifier module 511 is indicated at the CUR1 mark shown. The low-frequency current can be marked as follows: Figure 3 The ADCUR1 shown.

[0087] The low-frequency current amplification module 511 may include a comparator amplifier 5111. The comparator amplifier 5111 is an important circuit that measures and responds to changes between its input and reference terminals. It can be used to measure minute differences in current, thereby amplifying low-frequency current.

[0088] In other words, the low-frequency current amplification module 511 of this application is connected to both ends of the first resistor R1, and can amplify the initial low-frequency current collected by the first resistor R1 to obtain the amplified low-frequency current, so that the difference between the low-frequency current and the high-frequency current of the high-frequency current detection module 52 can be calculated more conveniently.

[0089] Please see Figure 4 In some embodiments, the high-frequency current detection module 52 includes a second resistor R2 and a high-frequency current amplification module 521 connected in parallel with the second resistor R2. The first end of the second resistor R2 is connected to the emitter of the driving power transistor, and the second end of the second resistor R2 is grounded. The output terminal of the high-frequency current amplification module 521 is connected to the input terminal of the control module 30. The second resistor R2 is used to acquire the initial high-frequency current. The high-frequency current amplification module 521 is used to amplify the initial high-frequency current to obtain the final high-frequency current.

[0090] The internal circuit structure of the high-frequency current amplifier module 521 is as follows: Figure 4 As shown. The first input terminal CUR1 of the high-frequency current amplification module 521 is connected to... Figure 2 As shown by the CUR1 marking, the second input terminal CUR2 of the high-frequency current amplification module 521 is connected to... Figure 2 The high-frequency current output of the high-frequency current amplifier module 521 is indicated at the CUR2 mark shown. The mark can be as follows: Figure 4 The ADCUR2 shown.

[0091] Please refer to the following: Figures 5 to 8 When two resonant heating modules 10 are connected in parallel, the second resistor R2 includes a resistor R21 connected to the first driving power transistor 21 and a resistor R22 connected to the second driving power transistor 22. The high-frequency current amplification module 521 may include a first high-frequency current amplification module 5211 and a second high-frequency current amplification module 5212.

[0092] The first high-frequency current amplification module 5211 is connected in parallel across the two ends of resistor R21, and the first end of the first high-frequency current amplification module 5211 is connected to... Figure 5 At the CUR1 marking, the second end of the first high-frequency current amplification module 5211 is connected to... Figure 5 The CUR2 identifier. The high-frequency current output of the first high-frequency current amplifier module 5211 can be identified as follows: Figure 7 The ADCUR2 shown.

[0093] The second high-frequency current amplification module 5212 is connected in parallel across the two ends of resistor R22, and the first end of the second high-frequency current amplification module 5212 is connected to... Figure 5 At the CUR1 marking, the second terminal of the second high-frequency current amplifier module 5212 is connected to... Figure 5 The CUR3 marking is located at the output terminal of the second high-frequency current amplifier module 5212. The high-frequency current marking at the output terminal can be as follows: Figure 8 The ADCUR3 shown.

[0094] Understandably, the internal circuit structure of the high-frequency current amplification module 521 can be the same as or different from the internal circuit structure of the low-frequency current amplification module 511, and no restriction is placed here. When the internal circuit structure of the high-frequency current amplification module 521 is the same as or different from the internal circuit structure of the low-frequency current amplification module 511, the amplification factor of the comparator amplifiers in both the high-frequency current amplification module 521 and the low-frequency current amplification module 511 can be set to be the same or different.

[0095] like Figure 4 As shown, the high-frequency current amplification module 521 may also include a comparator amplifier 5213. For example... Figure 7 and Figure 8 As shown, the first high-frequency current amplification module 5211 includes a comparator amplifier 52111, and the second high-frequency current amplification module 5212 includes a comparator amplifier 52121. A comparator amplifier is an important circuit that can be used to measure the change between the input terminal and the reference terminal and respond accordingly. It can be used to measure minute differences in current, thereby amplifying low-frequency currents.

[0096] In other words, the high-frequency current amplification module 521 of this application is connected across the two ends of the second resistor R2, which can amplify the initial high-frequency current collected by the second resistor R2 to obtain the amplified high-frequency current, thereby making it easier to calculate the difference with the low-frequency current of the low-frequency current detection module 51.

[0097] In some embodiments, the control module 30 is further configured to: if there is a difference between the low-frequency current and the high-frequency current and the difference is greater than a preset threshold, or the difference between the low-frequency current at the previous moment and the low-frequency current at the current moment is greater than a preset threshold, or the difference between the high-frequency current at the previous moment and the high-frequency current at the current moment is greater than a preset threshold, control the re-detection of the low-frequency current and the high-frequency current, and re-determine, based on the difference between the low-frequency current and the high-frequency current, whether the drive power transistor 20 corresponding to the resonant heating module 10 for heating the current cookware will be in a hard-on state or a freewheeling state to output a pulse control signal.

[0098] In other words, if the control module 30 calculates that the difference between the low-frequency current and the high-frequency current suddenly exceeds the preset threshold, or the difference fluctuates greatly, or the low-frequency current at the previous moment fluctuates greatly with the current moment, causing the difference between the low-frequency current at the previous moment and the current moment to exceed the preset threshold, or the high-frequency current at the previous moment fluctuates greatly with the current moment, causing the difference between the high-frequency current at the previous moment and the current moment to exceed the preset threshold, then it can be determined that the pot placed on the resonant heating module 10 connected between the high-frequency current detection module 52 and the low-frequency current detection module 51 has shifted.

[0099] Therefore, at this time, the control module 30 can control the re-detection of low-frequency current and high-frequency current, and re-determine whether the drive power transistor 20 corresponding to the resonant heating module 10 heating the current cookware will be in a hard-on state or a freewheeling state based on the difference between the low-frequency current and the high-frequency current, so as to output a pulse control signal, thereby ensuring that the drive power transistor 20 corresponding to the resonant heating module 10 heating the current cookware can be accurately protected from damage.

[0100] This application also provides an induction cooker. The induction cooker includes the control circuit 100 described in the above embodiments.

[0101] Thus, the control circuit 100 in the induction cooker of this application determines whether the drive power transistor 20 connected to the resonant heating module 10 is in a hard-on state or a freewheeling state by real-time detection of the high-frequency current and low-frequency current of electromagnetic induction heating. According to different states, the conduction time of the drive power transistor 20 is increased or decreased to control the heating power of the resonant heating module 10 to increase or decrease, thereby protecting the drive power transistor 20.

[0102] This application also provides a control method for the control circuit 100 described in any of the above embodiments.

[0103] Control methods include:

[0104] 01: Real-time detection of low-frequency current when the drive power transistor is turned on;

[0105] 02: Real-time detection of high-frequency current when the drive power transistor is turned on;

[0106] 03: Calculate the difference between the low-frequency current and the high-frequency current, and determine whether the corresponding drive power transistor of the resonant heating module will be in a hard-on state or a freewheeling state to output a pulse control signal based on the magnitude of the difference.

[0107] 04: Receive pulse control signals and control the conduction time of the drive power transistor according to the pulse control signals in order to control the heating power of the resonant heating module.

[0108] Specifically, the circuit structure and control working principle of the control circuit 100 are as described above, and will not be repeated here.

[0109] Thus, the control method of this application enables the control circuit 100 to determine whether the power transistor will be in a hard-on state or a freewheeling state by detecting the high-frequency current and low-frequency current of electromagnetic induction heating, so as to control the conduction time of the driving power transistor and protect the power transistor.

[0110] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A control circuit, characterized in that, The control circuit includes a resonant heating module, a driving power transistor, a control module, a driving module, a low-frequency current detection module, and a high-frequency current detection module. The input terminal of the low-frequency current detection module is connected to the first terminal of the resonant heating module, and the output terminal of the low-frequency current detection module is connected to the input terminal of the control module. The second terminal of the resonant heating module is connected to the collector of the driving power transistor. The emitter of the driving power transistor is connected to the first terminal of the high-frequency current detection module. The output terminal of the high-frequency current detection module is connected to the input terminal of the control module. The second terminal of the high-frequency current detection module is grounded. The output terminal of the control module is connected to the input terminal of the driving module, and the gate of the driving power transistor is connected to the output terminal of the driving module. The resonant heating module is used to heat cookware; The low-frequency current detection module is used to detect the low-frequency current when the drive power transistor is turned on in real time. The high-frequency current detection module is used to detect the high-frequency current when the drive power transistor is turned on in real time. The control module is used to calculate the difference between the low-frequency current and the high-frequency current, and to determine whether the driving power tube corresponding to the resonant heating module will be in a hard-on state or a freewheeling state based on the magnitude of the difference in order to output a pulse control signal. The driving module is used to receive the pulse control signal and control the conduction time of the driving power transistor according to the pulse control signal, so as to control the heating power of the resonant heating module.

2. The control circuit according to claim 1, characterized in that, The control module is used for: If the difference is greater than a preset threshold, it is determined that the driving power transistor corresponding to the resonant heating module is in a freewheeling state. The duty cycle of the pulse control signal received by the driving power transistor is reduced to reduce the conduction time of the driving power transistor, thereby reducing the heating power of the resonant heating module.

3. The control circuit according to claim 2, characterized in that, The control module is used for: Based on the low-frequency current, the high-frequency current, and the amplification factor of the low-frequency current detection module and the amplification factor of the high-frequency current detection module, calculate the hard-on current of the driving power transistor when the resonant heating module operates at a power lower than a predetermined power threshold. If the hard-on current is greater than the hard-on current threshold, it is determined that the driving power transistor corresponding to the resonant heating module will be in a hard-on state. The duty cycle of the pulse control signal received by the driving power transistor is increased to increase the conduction time of the driving power transistor, thereby controlling and increasing the heating power of the resonant heating module, so that the resonant heating module operates within a preset power range.

4. The control circuit according to claim 1, characterized in that, The control circuit includes multiple resonant heating modules, multiple drive power transistors connected to the resonant heating modules, multiple drive modules, and multiple high-frequency current detection modules, wherein the multiple resonant heating modules are connected in parallel; the control module is used for: Calculate the difference between the low-frequency current and the high-frequency current of each of the multiple resonant heating modules; Based on the magnitude of the difference, it is determined whether the multiple driving power transistors corresponding to the multiple resonant heating modules are in a hard-on state or a freewheeling state, so as to output the pulse control signal.

5. The control circuit according to claim 4, characterized in that, The control module is used for: If the difference between the low-frequency current and the high-frequency current corresponding to at least one of the resonant heating modules exceeds a preset threshold, it is determined that the driving power transistor corresponding to the resonant heating module will be in a freewheeling state. The duty cycle of the pulse control signal received by the corresponding at least one driving power transistor is reduced to reduce the conduction time of at least one driving power transistor and reduce the heating power of at least one resonant heating module so that at least one resonant heating module operates within a preset power range.

6. The control circuit according to claim 4, characterized in that, The control module is used for: Based on the low-frequency current, the multiple high-frequency currents, and the amplification factor of the low-frequency current detection module and the amplification factor of the high-frequency current detection module, the hard-on current of the multiple driving power transistors when the multiple resonant heating modules operate at a power lower than a predetermined power threshold is calculated respectively. If at least one of the hard-on currents is greater than the hard-on current threshold, it is determined that the driving power transistor corresponding to at least one of the resonant heating modules will be in a hard-on state. The duty cycle of the pulse control signal received by at least one of the driving power transistors is increased to increase the conduction time of at least one of the driving power transistors. The heating power corresponding to at least one of the resonant heating modules is increased so that at least one of the resonant heating modules operates within a preset power range.

7. The control circuit according to claim 1, characterized in that, The low-frequency current detection module includes a first resistor and a low-frequency current amplification module connected in parallel with the first resistor. The first resistor is connected to the first end of the resonant heating module. The output end of the low-frequency current amplification module is connected to the input end of the control module. The first resistor is used to acquire the initial low-frequency current; The low-frequency current amplification module is used to amplify the initial low-frequency current to obtain the low-frequency current.

8. The control circuit according to claim 1, characterized in that, The high-frequency current detection module includes a second resistor and a high-frequency current amplification module connected in parallel with the second resistor. The first end of the second resistor is connected to the emitter of the driving power transistor, and the second end of the second resistor is grounded. The output end of the high-frequency current amplification module is connected to the input end of the control module. The second resistor is used to acquire the initial high-frequency current; The high-frequency current amplification module is used to amplify the initial high-frequency current to obtain the high-frequency current.

9. The control circuit according to claim 1, characterized in that, The control module is also used for: If there is a difference between the low-frequency current and the high-frequency current and the difference is greater than a preset threshold, or if the difference between the low-frequency current at the previous moment and the low-frequency current at the current moment is greater than a preset threshold, or if the difference between the high-frequency current at the previous moment and the high-frequency current at the current moment is greater than a preset threshold, the system controls the re-detection of the low-frequency current and the high-frequency current, and re-determines, based on the difference between the low-frequency current and the high-frequency current, whether the drive power transistor corresponding to the resonant heating module for heating the current cookware will be in a hard-on state or a freewheeling state to output the pulse control signal.

10. The control circuit according to claim 1, characterized in that, The control circuit further includes a power supply module, a first filter module, a rectifier module, and a second filter module. The input terminal of the first filter module is connected to the power supply module, the first output terminal of the first filter module is connected to the input terminal of the rectifier module, and the second output terminal of the first filter module is connected to the control module. The first output terminal of the rectifier module is connected to the first input terminal of the second filter module, and the second output terminal of the rectifier module is connected to the second input terminal of the second filter module through the low-frequency current detection module. The output terminal of the second filter module is connected to the first terminal of the resonant heating module. The power module is used to provide electrical energy; The first filtering module is used to filter the AC signal emitted by the power supply module; The rectifier module is used to convert the AC signal after filtering by the first filter module into a DC signal. The second filtering module is used to filter the DC signal processed by the rectifier module.

11. An electromagnetic cooker, characterized in that, The induction cooker includes the control circuit described in any one of claims 1 to 10.

12. A control method for the control circuit according to any one of claims 1 to 10, characterized in that, The control method includes: Real-time detection of the low-frequency current when the drive power transistor is turned on; Real-time detection of the high-frequency current when the drive power transistor is turned on; Calculate the difference between the low-frequency current and the high-frequency current, and determine whether the driving power transistor corresponding to the resonant heating module will be in a hard-on state or a freewheeling state based on the magnitude of the difference in order to output a pulse control signal. The system receives the pulse control signal and controls the conduction time of the drive power transistor according to the pulse control signal, so as to control the heating power of the resonant heating module.

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