Control circuit of induction cooker

Abstract

The utility model relates to the technical field of induction cookers, and discloses a control circuit of an induction cooker, which comprises a mains supply end, a dual-pressure-sensitive pi-type filtering module, a rectification sampling module, a switching power supply module, a switching tube driving module and a control module. High-order harmonics in mains supply voltage are filtered through the dual-voltage-sensitive pi-type filtering module, the filtered mains supply voltage is output, secondary improvement is conducted on the input mains supply voltage through secondary voltage sensitive, high-voltage group pulses and lightning stroke voltage surges in the mains supply are effectively absorbed, the surges generated due to inductive load sudden change in the working process of an induction cooker circuit are effectively blocked, and the working efficiency of the induction cooker circuit is improved. And the interference of the induction cooker circuit on the power supply is reduced. Through cooperative control of the dual-pressure-sensitive pi-type filtering module, the rectification sampling module, the switching power supply module, the switching tube driving module and the control module, a safer and more efficient control circuit is formed, and the safety and reliability, the electromagnetic compatibility and the user experience of the induction cooker circuit are greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of induction cooker technology, and in particular to a control circuit for an induction cooker. Background Technology

[0002] In existing technologies, most control circuits use varistors in filter circuits to prevent the circuit from being affected by surges. However, varistors are resistive components. Although they are voltage-sensitive—meaning that when the voltage is below the operating voltage, the resistance of the varistor is very high, with only microamps of leakage current and almost no power consumption—when the operating voltage is reached, the resistance decreases sharply, and the current suddenly increases. However, the resistive characteristic remains, and the voltage across the varistor still exhibits a VA characteristic, causing the voltage to continue to rise. Therefore, the effect of a single-stage varistor in eliminating high voltage is not satisfactory. Furthermore, due to the inductive load characteristics of induction cookers, which also have internal inductors, reverse high voltage can easily be generated in the inductors of the filter circuit. Utility Model Content

[0003] The purpose of this utility model is to provide a control circuit for an induction cooker to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.

[0004] The solution to the technical problem of this utility model is to provide a control circuit for an induction cooker.

[0005] In some embodiments of this utility model, a control circuit for an induction cooker includes: the induction cooker includes a coil, and the control circuit includes: a mains power supply terminal, a dual varistor π-type filter module, a rectifier sampling module, a switching power supply module, a switching transistor drive module, and a control module;

[0006] The input terminal of the dual varistor π-type filter module is connected to the mains power supply terminal, and the output terminal of the dual varistor π-type filter module is connected to the input terminal of the rectifier sampling module.

[0007] The output terminal of the rectifier sampling module is connected to the input terminal of the control module, and the output terminal of the rectifier sampling module is connected to the coil disk;

[0008] The input terminal of the switching power supply module is connected to the output terminal of the dual varistor π-type filter module, and the output terminal of the switching power supply module is connected to the control module and the switching transistor drive module respectively.

[0009] The input terminal of the switching transistor drive module is connected to the output terminal of the control module, and the output terminal of the switching transistor drive module is connected to the coil disk. The switching transistor drive module is used to receive the switching transistor drive signal output by the control module and drive the coil disk to run.

[0010] Furthermore, the dual-varistor π-type filter module includes: a bleeder resistor, a first varistor, a second varistor, a first capacitor, a second capacitor, and a common-mode inductor;

[0011] The bleeder resistor is connected to the mains power supply terminal, the first capacitor is connected in parallel with the bleeder resistor, the first varistor is connected in parallel with the first capacitor, and one end of each of the two coils of the common mode inductor is connected to the first varistor.

[0012] The second varistor is connected in parallel with the second capacitor, the second capacitor is connected to the input terminal of the rectifier sampling module, and the other ends of the two coils of the common mode inductor are both connected to the second varistor.

[0013] Furthermore, the control circuit of an induction cooker also includes: a thyristor drive module and a third varistor;

[0014] The input terminal of the thyristor drive module is connected to the output terminal of the rectifier sampling module and the output terminal of the control module, respectively, and the thyristor drive module is connected to the output terminal of the switching power supply module.

[0015] The third varistor is connected to the output terminal of the thyristor drive module and to the coil disk.

[0016] Furthermore, the control circuit of an induction cooker also includes: a mains power acquisition module;

[0017] The input terminal of the mains power acquisition module is connected to the output terminal of the dual varistor π-type filter module, and the output terminal of the mains power acquisition module is connected to the input terminal of the control module. The mains power acquisition module is used to acquire mains voltage and mains current.

[0018] Furthermore, the thyristor driving module includes: an optocoupler isolator, a thyristor, and a first resistor;

[0019] The positive terminal of the thyristor is connected to the output terminal of the rectifier sampling module, the control terminal of the thyristor is connected to the first resistor, and the negative terminal of the thyristor is connected to the third varistor and the output terminal of the switching power supply module, respectively.

[0020] The output terminal of the optocoupler is connected to the first resistor and the output terminal of the switching power supply module, respectively, and the input terminal of the optocoupler is connected to the output terminal of the control module and the output terminal of the switching power supply module, respectively.

[0021] Furthermore, the control circuit of an induction cooker also includes: a resistor voltage divider module;

[0022] The output terminal of the resistor voltage divider module is connected to the input terminal of the control module and the input terminal of the switching transistor drive module, respectively, and the input terminal of the resistor voltage divider module is electrically connected to the coil disk.

[0023] Furthermore, the resistor voltage divider module includes: a first series resistor group and a second series resistor group;

[0024] The first series resistor group is connected to the coil disk and the input terminal of the control module, respectively. The second series resistor group is connected to the coil disk, the input terminal of the control module and the input terminal of the switching transistor drive module, respectively.

[0025] Furthermore, the switching power supply module includes: a power chip, a filter and voltage regulator circuit, a transformer, a first power transmission terminal, a first step-down circuit, and a second power transmission terminal;

[0026] The input terminal of the power chip is connected to the output terminal of the dual-varistor π-type filter module, and the output terminal of the power chip is connected to the input terminal of the filter and voltage regulator circuit.

[0027] The output terminal of the filter and voltage regulator circuit is connected to the main coil of the transformer, the main coil of the transformer is connected to the first power transmission terminal, and the first power transmission terminal is connected to the switching transistor drive module.

[0028] The input terminal of the first step-down circuit is connected to the first secondary coil of the transformer, the output terminal of the first step-down circuit is connected to the second power transmission terminal, and the second power transmission terminal is connected to the control module and the thyristor drive module respectively.

[0029] Furthermore, the switching power supply module also includes: a second step-down circuit and a third power transmission terminal;

[0030] The input terminal of the second step-down circuit is connected to the second secondary coil of the transformer, and the output terminal of the second step-down circuit is connected to the third power transmission terminal, which is connected to the thyristor drive module.

[0031] Furthermore, the switching transistor driving module includes an ACD-049 driver chip.

[0032] The beneficial effects of this invention are as follows: By using a dual-varistor π-type filter module, high-order harmonics in the mains voltage are filtered, and the filtered mains voltage is output. A secondary varistor further improves the input mains voltage, effectively absorbing high-voltage pulse bursts and lightning surges. It also effectively blocks surges caused by sudden changes in inductive load during the operation of the induction cooker circuit, reducing interference from the induction cooker circuit to the power supply and effectively improving the quality, safety, and electromagnetic compatibility performance of the induction cooker. Through the coordinated control of the dual-varistor π-type filter module, rectifier sampling module, switching power supply module, switching transistor drive module, and control module, a safer and more efficient control circuit is formed, greatly improving the safety and reliability of the induction cooker circuit and the continuously adjustable power range, thereby enhancing electromagnetic compatibility performance and user experience. Attached Figure Description

[0033] Figure 1This is a partial circuit diagram of the control circuit of an induction cooker provided in one embodiment of the present invention;

[0034] Figure 2 This is a partial circuit diagram of the control circuit of an induction cooker provided in another embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the control circuit framework of an induction cooker provided in one embodiment of the present invention.

[0036] Reference numerals: 100, Mains power supply terminal; 110, Coil disk; 200, Dual varistor π-type filter module; 300, Rectifier sampling module; 400, Switching power supply module; 410, Filtering and voltage regulation circuit; 420, First step-down circuit; 430, Second step-down circuit; VDD, First transmission terminal; VCC, Second transmission terminal; CN1, Third transmission terminal; 500, Control module; 600, Switching transistor drive module; 700, Thyristor drive module; 800, Mains power acquisition module; 900, Resistor voltage divider module. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and should not be construed as limiting the scope of this invention.

[0038] It should be noted that although the functional circuits are divided in the schematic diagram, in some cases, the circuits can be divided differently from those in the system.

[0039] Furthermore, 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 technical features indicated. Therefore, a feature defined as "first" and "second" may explicitly or implicitly include one or more features.

[0040] In the description of this utility model, it should be noted that, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0041] Reference Figures 1 to 3 In some embodiments of this utility model, the control circuit of an induction cooker includes: a switching transistor drive module 600, a control module 500, a switching power supply module 400, a rectification sampling module 300, a mains power supply terminal 100, and a dual varistor π-type filter module 200.

[0042] The AC power supply terminal 100 is electrically connected to the power supply line, the AC power supply terminal 100 is electrically connected to the input terminal of the dual varistor π-type filter module 200, and the output terminal of the dual varistor π-type filter module 200 is electrically connected to the input terminal of the rectifier sampling module 300.

[0043] The dual-varistor π-type filter module 200 receives the mains voltage output from the mains power supply terminal 100, filters out high-order harmonics in the mains voltage, and outputs the filtered mains voltage. This effectively absorbs high-voltage bursts and lightning voltage surges in the mains power supply, effectively improving the quality, safety, and EMC (electromagnetic compatibility) performance of the induction cooker.

[0044] The output terminal of the rectifier sampling module 300 is electrically connected to the input terminal of the control module 500. The rectifier sampling module 300 rectifies and samples the filtered mains voltage to obtain the operating current, and outputs the operating current to the control module 500 to realize the operating current of the control module 500 and detect the operating current. The rectifier bridge circuit in the rectifier sampling module 300 is a rectifier bridge circuit with an integrated current sampling sensor.

[0045] The input terminal of the switching power supply module 400 is electrically connected to the output terminal of the dual varistor π-type filter module 200, the output terminal of the switching power supply module 400 is electrically connected to the control module 500, and the output terminal of the switching power supply module 400 is electrically connected to the switching transistor drive module 600. The switching power supply module 400 is used to output power supply.

[0046] The input terminal of the switching transistor drive module 600 is electrically connected to the output terminal of the control module 500, and the output terminal of the switching transistor drive module 600 is electrically connected to the coil 110 of the induction cooker. The control module 500 outputs a switching transistor drive signal to control the magnitude of the turn-on current of the switching transistor drive module 600, thereby adjusting the on and off time of the power switching transistor IGBT, and thus driving the regulating coil 110.

[0047] This invention utilizes the coordinated control of a dual-pressure-sensitive π-type filter module 200, a rectifier sampling module 300, a switching power supply module 400, a control module 500, and a switching transistor drive module 600 to form a safer and more efficient control circuit. This significantly improves the safety and reliability of the induction cooker circuit and the continuously adjustable power range, thereby enhancing electromagnetic compatibility performance and user experience.

[0048] Reference Figures 1 to 3 In some embodiments of this utility model, the dual varistor π-type filter module 200 includes: a first varistor RZ1, a bleeder R2, a common mode inductor T1, a second varistor RZ2, a second capacitor C2, and a first capacitor C1.

[0049] Both ends of the bleed resistor R2 are electrically connected to the mains power supply terminal 100. One end of the bleed resistor R2 is electrically connected to one end of the first capacitor C1, and the other end of the bleed resistor R2 is electrically connected to the other end of the first capacitor C1, so that the bleed resistor R2 and the first capacitor C1 are connected in parallel.

[0050] The discharge resistor R2 is used to discharge the voltage stored in the π-type filter circuit composed of the first varistor RZ1, the common mode inductor T1, the second varistor RZ2, the first capacitor C1, and the second capacitor C2. This prevents the energy stored in the module from damaging equipment or personnel when the power supply line is disconnected and the circuit is left unattended, thereby improving the safety of the induction cooker.

[0051] One end of the first capacitor C1 is electrically connected to one end of the first varistor RZ1, and the other end of the first capacitor C1 is electrically connected to the other end of the first varistor RZ1, so that the first capacitor C1 and the first varistor RZ1 are connected in parallel.

[0052] One end of the first varistor RZ1 is electrically connected to one end of the first coil of the common-mode inductor T1, and the other end of the first varistor RZ1 is electrically connected to one end of the second coil of the common-mode inductor T1, so that the first varistor RZ1 is electrically connected to one end of each of the two coils of the common-mode inductor T1 respectively.

[0053] One end of the second capacitor C2 is electrically connected to one end of the second varistor RZ2, and the other end of the second capacitor C2 is electrically connected to the other end of the second varistor RZ2, so that the second capacitor C2 and the second varistor RZ2 are connected in parallel.

[0054] One end of the second varistor RZ2 is electrically connected to the other end of the first coil of the common-mode inductor T1, and the other end of the second varistor RZ2 is electrically connected to the other end of the second coil of the common-mode inductor T1, so that the second varistor RZ2 is electrically connected to the other ends of the two coils of the common-mode inductor T1 respectively.

[0055] In this embodiment, the common-mode inductor T1 is used as a choke. A π-type filter circuit is formed by the common-mode inductor T1, the first varistor RZ1, the first capacitor C1, the second varistor RZ2, and the second capacitor C2. Two stages of varistors are used to enhance the ability to eliminate high voltage from the power supply, thus achieving secondary voltage improvement. This module not only blocks occasional surge voltages in the power supply, protecting the induction cooker circuit from surge damage, but also effectively blocks surges caused by sudden changes in inductive load during the operation of the induction cooker circuit. This reduces interference from the induction cooker circuit to the power supply and prevents the reverse high voltage generated by the inductor in the filter circuit from affecting the circuit.

[0056] Reference Figures 1 to 3In some embodiments of this utility model, the control circuit further includes: a third varistor RZ3 and a thyristor drive module 700.

[0057] The input terminal of the thyristor drive module 700 is electrically connected to the output terminal of the rectifier sampling module 300, the input terminal of the thyristor drive module 700 is electrically connected to the output terminal of the control module 500, and the output terminal of the thyristor drive module 700 is electrically connected to one end of the third varistor RZ3.

[0058] One end of the third varistor RZ3 is electrically connected to the coil disk 110, and the other end of the third varistor RZ3 is grounded.

[0059] In this embodiment, refer to Figure 1 Adding a third varistor RZ3 after the rectifier sampling module 300 protects the rectifier bridge. With continuously stabilizing voltage, the switching transistor drive module 600 receives better protection, preventing damage from lightning strikes. Compared to existing technologies that use diodes for protection, this application employs a two-stage and a three-stage varistor, namely the second varistor RZ2 and the third varistor RZ3, offering stronger protection capabilities, lower cost, and simpler manufacturing processes. The combined effect of the second and third varistor RZ3 improves the effectiveness of blocking surges caused by sudden load changes during induction cooker circuit operation, significantly reducing interference from the induction cooker circuit to the power supply.

[0060] Reference Figures 1 to 3 In some embodiments of this utility model, the thyristor drive module 700 includes: a first resistor R1, a thyristor SCR, and an optocoupler PT1.

[0061] The positive terminal of the SCR is electrically connected to the output terminal of the rectifier sampling module 300, and the negative terminal of the SCR is electrically connected to the output terminal of the switching power supply module 400. The negative terminal of the SCR is also electrically connected to the third varistor RZ3 and the coil disk 110. The control terminal of the SCR is electrically connected to one end of the first resistor R1.

[0062] The other end of the first resistor R1 is electrically connected to the emitter port of the optocoupler PT1 to achieve electrical connection with the output terminal of the optocoupler PT1.

[0063] The collector port of the optocoupler PT1 is electrically connected to the output terminal of the switching power supply module 400 to realize the electrical connection between the output terminal of the optocoupler PT1 and the output terminal of the switching power supply module 400.

[0064] The anode port of the optocoupler PT1 is electrically connected to the output terminal of the switching power supply module 400, so as to realize the electrical connection between the input terminal of the optocoupler PT1 and the output terminal of the switching power supply module 400.

[0065] The cathode port of the optocoupler PT1 is electrically connected to the control module 500 to realize the electrical connection between the input terminal of the optocoupler PT1 and the control module 500.

[0066] In this embodiment, the SCR drive module 700 is used to drive the SCR to cut the output wave at high frequency, replacing the relay switching method used in the prior art. This reduces the standby power of the whole machine and greatly reduces the electromagnetic noise during low-power operation. During continuous low-power operation, the operating temperature of the switching transistor drive module 600 is reduced, which can reduce the cooling fan speed and reduce wind noise.

[0067] Reference Figure 1 In some embodiments of this utility model, the control circuit further includes: a first diode D1, a second diode D2, and a mains power acquisition module 800.

[0068] The anode of the first diode D1 is electrically connected to one end of the second capacitor C2, and the cathode of the first diode D1 is electrically connected to the input terminal of the mains power acquisition module 800.

[0069] The anode of the second diode D2 is electrically connected to the other end of the second capacitor C2, and the cathode of the first diode D1 is electrically connected to the input terminal of the mains power acquisition module 800, so that the input terminal of the mains power acquisition module 800 is electrically connected to the output terminal of the dual varistor π-type filter module 200.

[0070] The mains power acquisition module 800 collects the mains voltage and mains current for the control module 500 to detect and monitor, and monitors the ability of the dual varistor π-type filter module 200 to eliminate the high voltage of the power supply and protect the induction cooker circuit from surge damage.

[0071] The mains power acquisition module 800 includes: a third resistor R3, a fourth resistor R4, a fifth resistor R5, a seventh resistor R7, and an eighth resistor R8.

[0072] The third resistor R3, the fourth resistor R4, and the fifth resistor R5 form a series resistor group. One end of the third resistor R3 is electrically connected to the cathode of the first diode D1 and the cathode of the second diode D2. The other end of the third resistor R3 is electrically connected to one end of the fourth resistor R4 and one end of the eighth resistor R8, respectively.

[0073] The other end of the fourth resistor R4 is electrically connected to one end of the fifth resistor R5, and the other end of the fifth resistor R5 is grounded. The other end of the eighth resistor R8 is electrically connected to the control module 500. Through the eighth resistor R8, the mains voltage is collected so that the control module 500 can detect the mains voltage and monitor the ability of the dual varistor π-type filter module 200 to eliminate the high voltage of the power supply.

[0074] One end of the fifth resistor R5 is electrically connected to one end of the seventh resistor R7, and the other end of the seventh resistor R7 is electrically connected to the input terminal of the control module 500. Through the seventh resistor R7, the mains current is collected so that the control module 500 can detect the surge of the mains power to protect the induction cooker circuit from surge damage.

[0075] Reference Figure 1 In some embodiments of this utility model, the control circuit further includes a resistor voltage divider module 900.

[0076] The input terminal of the resistor voltage divider module 900 is electrically connected to the coil disk 110, the output terminal of the resistor voltage divider module 900 is electrically connected to the input terminal of the control module 500, and the output terminal of the resistor voltage divider module 900 is also electrically connected to the input terminal of the switching transistor drive module 600.

[0077] The resistor voltage divider module 900 includes: a first series resistor group and a second series resistor group.

[0078] The first series resistor group is formed by connecting the ninth resistor R9 and the tenth resistor R10 in series. One end of the ninth resistor R9 is electrically connected to the coil disk 110, and one end of the tenth resistor R10 is electrically connected to the other end of the ninth resistor R9. The other end of the tenth resistor R10 is grounded. The output terminal of the control module 500 is electrically connected to the other end of the ninth resistor R9.

[0079] The second series resistor group is formed by connecting the eleventh resistor R11, the twelfth resistor R12, the thirteenth resistor R13, and the fourteenth resistor R14 in series. One end of the eleventh resistor R11 is electrically connected to the coil disk 110, and the other end of the eleventh resistor R11 is electrically connected to the input terminal of the switching transistor drive module 600. One end of the fourteenth resistor R14 is electrically connected to the thirteenth resistor R13, and the other end of the fourteenth resistor R14 is electrically connected to the input terminal of the switching transistor drive module 600. The other end of the fourteenth resistor R14 is grounded.

[0080] By setting a resistor voltage divider module 900 at both ends of the coil disk 110, a synchronous signal of electromagnetic oscillation energy change is provided to the control module 500 and the switching transistor drive module 600, so that the control module 500 can monitor the coil disk 110 and provide an energy conversion signal to the switching transistor drive module 600, so that the switching transistor drive module 600 can make adaptive adjustments according to the energy change of the coil disk 110.

[0081] Reference Figure 1 and Figure 3 In some embodiments of this utility model, the switching power supply module 400 includes: a filter and voltage regulator circuit 410, a first step-down circuit 420, a second step-down circuit 430, a power chip U1, a transformer T2, a first power transmission terminal VDD, a second power transmission terminal VCC, and a third power transmission terminal CN1.

[0082] The fifth, sixth, seventh, and eighth pins of power chip U1 are all connected to...

[0083] The output terminal of the dual varistor π-type filter module 200 is electrically connected to realize the electrical connection between the input terminal of the power chip U1 and the output terminal of the dual varistor π-type filter module 200. The first and second pins of the power chip U1 are both connected to the input terminal of the filter and voltage regulator circuit 410 to realize the connection between the output terminal of the power chip U1 and the input terminal of the filter and voltage regulator circuit 410.

[0084] The output terminal of the filter and voltage regulator circuit 410 is electrically connected to the main coil of transformer T2, and the first transmission terminal VDD is also electrically connected to the main coil of transformer T2 and the switching transistor driver module 600. Through the first transmission terminal VDD, the switching power supply module 400 supplies power to the switching transistor driver module 600.

[0085] The filter and voltage regulator circuit 410 includes a third diode D3, a fourth diode D4, and a seventh capacitor C7.

[0086] The positive terminal of the seventh capacitor C7 is electrically connected to the first pin of the power supply chip U1, the negative terminal of the seventh capacitor C7 is electrically connected to the cathode of the fourth diode D4, the negative terminal of the seventh capacitor C7 is electrically connected to the second pin of the power supply chip U1, the cathode of the fourth diode D4 is electrically connected to the other end of the main coil, and the anode of the fourth diode D4 is grounded. The anode of the third diode D3 is electrically connected to one end of the main coil of the transformer T2, and the cathode of the third diode D3 is electrically connected to the positive terminal of the seventh capacitor C7.

[0087] The first secondary coil of transformer T2 is electrically connected to the input terminal of the first step-down circuit 420. The output terminal of the first step-down circuit 420 is electrically connected to the second power supply terminal VCC. The second power supply terminal VCC is electrically connected to the anode port of optocoupler PT1. The second power supply terminal VCC is also electrically connected to the control module 500 and the fan drive module. Through the second power supply terminal VCC, the switching power supply module 400 supplies power to the control module 500, the fan drive module, and the thyristor drive module 700.

[0088] The first step-down circuit 420 includes: a step-down regulator chip U2, a fifth diode D5, an eighth capacitor C8, and a tenth capacitor C10.

[0089] The anode of the fifth diode D5 is electrically connected to one end of the first secondary coil of the transformer T2, the cathode of the fifth diode D5 is electrically connected to the positive terminal of the eighth capacitor C8, and the cathode of the fifth diode D5 is electrically connected to the second pin of the step-down voltage regulator chip U2.

[0090] The negative terminal of the eighth capacitor C8 is electrically connected to the other end of the first secondary coil of transformer T2, and the negative terminal of the eighth capacitor C8 is electrically connected to the third pin of the buck regulator chip U2. The positive terminal of the tenth capacitor C10 is electrically connected to the first pin of the buck regulator chip U2, and the negative terminal of the tenth capacitor C10 is grounded. The third pin of the buck regulator chip U2 is grounded. The first pin of the buck regulator chip U2 is electrically connected to the second output terminal.

[0091] The input terminal of the second step-down circuit 430 is electrically connected to the second secondary coil of the transformer T2, and the output terminal of the second step-down circuit 430 is electrically connected to the third transmission terminal CN1. The third transmission terminal CN1 is electrically connected to the collector port of the optocoupler PT1, and the third transmission terminal CN1 is also electrically connected to the negative terminal of the silicon controlled rectifier (SCR). Through the third transmission terminal CN1, the switching power supply module 400 supplies power to the SCR driver module 700.

[0092] The second step-down circuit 430 includes a sixth diode D6 and an eleventh capacitor C11.

[0093] The anode of the sixth diode D6 is electrically connected to one end of the second secondary coil of transformer T2, and the cathode of the sixth diode D6 is electrically connected to the positive terminal of the eleventh capacitor C11. The cathode of the sixth diode D6 is also electrically connected to the third transmission terminal CN1. The negative terminal of the eleventh capacitor C11 is electrically connected to the other end of the second secondary coil of transformer T2 and the third transmission terminal CN1.

[0094] Reference Figure 1 and Figure 3 In some embodiments of this utility model, the switching transistor driving module 600 includes: an ACD-049 driver chip U5, a power switching transistor IGBT, a first parallel capacitor group, a voltage divider resistor group, a twentieth resistor R20, a twenty-first resistor R21, a twenty-second resistor R22, a twenty-third resistor R23, a twenty-fourth resistor R24, an adjustable resistor RT1, a first Zener diode DZ1, and a second Zener diode DZ2.

[0095] The first and second pins of the ACD-049 driver chip U5 are electrically connected to the first parallel capacitor bank, and the first pin of the ACD-049 driver chip U5 is electrically connected to the first power transmission terminal VDD.

[0096] The third pin of the ACD-049 driver chip U5 is electrically connected to the output terminal of the control module 500 through the twenty-fourth resistor R24.

[0097] The fourth pin of the ACD-049 driver chip U5 is electrically connected to a voltage divider resistor group, which is formed by connecting the fifteenth resistor R15, the sixteenth resistor R16, and the seventeenth resistor R17.

[0098] One end of the fifteenth resistor R15 is electrically connected to the other end of the eleventh resistor R11 in the second series resistor group. The other end of the fifteenth resistor R15 is electrically connected to one end of the sixteenth resistor R16 and one end of the seventeenth resistor R17. The other end of the sixteenth resistor R16 is electrically connected to the fourth pin of the ACD-049 driver chip U5. The other end of the seventeenth resistor R17 is electrically connected to the other end of the fourteenth resistor R14 in the second series resistor group.

[0099] The fifth pin of the ACD-049 driver chip U5 is electrically connected to one end of the twenty-second resistor R22. The other end of the twenty-second resistor R22 is electrically connected to one end of the twenty-first resistor R21. The other end of the twenty-first resistor R21 is electrically connected to the gate of the power switching transistor IGBT.

[0100] The sixth pin of the ACD-049 driver chip U5 is electrically connected to the cathode of the second Zener diode DZ2 and one end of the second-thirteenth resistor R23. The anode of the second Zener diode DZ2 and the other end of the second-thirteenth resistor R23 are both electrically connected to the other end of the second-twentieth resistor R22.

[0101] The anode of the first Zener diode DZ1 is electrically connected to the emitter of the power switch IGBT and one end of the twentieth resistor R20. The cathode of the first Zener diode DZ1 is electrically connected to the gate of the power switch and the other end of the twentieth resistor R20. The anode of the first Zener diode DZ1 is grounded.

[0102] The collector of the power switching transistor IGBT is electrically connected to the coil disk 110. One end of the adjustable resistor RT1 is electrically connected to one end of the twentieth resistor R20, and the other end of the adjustable resistor RT1 is electrically connected to the control module 500.

[0103] The second series resistor group is connected to the voltage divider resistor group, so that the second series resistor group provides a synchronization signal for the change in electromagnetic oscillation energy to the ACD-049 driver chip U5. This provides the ACD-049 driver chip U5 with an energy conversion signal, which can adjust the turn-on level of the power switching transistor IGBT according to the change in the inductance of the coil 110. By using the ACD-049 driver chip U5, the safety of the power switching transistor IGBT operation is improved, the specification requirements for the IGBT can be reduced, and the induction cooker can operate continuously at low power.

[0104] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A control circuit for an induction cooker, characterized in that: The induction cooker includes a coil disk, and the control circuit includes: a mains power supply terminal, a dual-varistor π-type filter module, a rectifier sampling module, a switch power supply module, a switch tube drive module and a control module; The input end of the dual-voltage-sensitive π-type filter module is connected to the mains power supply end, and the output end of the dual-voltage-sensitive π-type filter module is connected to the input end of the rectifier sampling module; The output end of the rectification sampling module is connected to the input end of the control module, and the output end of the rectification sampling module is connected to the coil disk; The input end of the switching power supply module is connected to the output end of the dual-varistor π-type filter module, and the output end of the switching power supply module is connected to the control module and the switch tube driving module respectively; The input end of the switch tube driving module is connected to the output end of the control module, and the output end of the switch tube driving module is connected to the coil disk. The switch tube driving module is used to receive the switch tube driving signal output by the control module to drive the coil disk to operate.

2. The control circuit of an induction cooker according to claim 1, characterized in that: The dual-varistor π-type filter module includes: a bleeder resistor, a first varistor, a second varistor, a first capacitor, a second capacitor and a common-mode inductor; The discharge resistor is connected to the mains power supply terminal, the first capacitor is connected in parallel to the discharge resistor, the first varistor is connected in parallel to the first capacitor, and one end of the two coils of the common mode inductor is connected to the first varistor; The second varistor is connected in parallel with the second capacitor, the second capacitor is connected to the input end of the rectification sampling module, and the other ends of the two coils of the common mode inductor are both connected to the second varistor.

3. The control circuit of an induction cooker according to claim 1, characterized in that: Also includes: Thyristor drive module and third varistor; The input end of the thyristor driving module is connected to the output end of the rectifier sampling module and the output end of the control module respectively, and the thyristor driving module is connected to the output end of the switching power supply module; The third varistor is connected to the output end of the thyristor driving module, and the third varistor is connected to the coil disk.

4. The control circuit of an induction cooker according to claim 1, characterized in that: Also includes: Mains power collection module; The input end of the mains power acquisition module is connected to the output end of the dual-piezoresistance π-type filter module, the output end of the mains power acquisition module is connected to the input end of the control module, and the mains power acquisition module is used to collect the mains voltage and the mains current.

5. The control circuit of an induction cooker according to claim 3, characterized in that: The thyristor driving module comprises: an optocoupler isolator, a thyristor and a first resistor; The positive terminal of the thyristor is connected to the output terminal of the rectifier sampling module, the control terminal of the thyristor is connected to the first resistor, and the negative terminal of the thyristor is connected to the third varistor and the output terminal of the switching power supply module respectively; The output end of the optocoupler isolator is connected to the first resistor and the output end of the switch power module respectively, and the input end of the optocoupler isolator is connected to the output end of the control module and the output end of the switch power module respectively.

6. The control circuit of an induction cooker according to claim 1, characterized in that: Also includes: a resistor voltage divider module; The output end of the resistor voltage divider module is respectively connected to the input end of the control module and the input end of the switch tube driving module, and the input end of the resistor voltage divider module is electrically connected to the coil disk.

7. The control circuit of an induction cooker according to claim 6, characterized in that: The resistor voltage divider module includes: a first series resistor group and a second series resistor group; The first series resistor group is connected to the coil disk and the input end of the control module respectively, and the second series resistor group is connected to the coil disk, the input end of the control module and the input end of the switch tube driving module respectively.

8. The control circuit of an induction cooker according to claim 3, characterized in that: The switching power supply module includes: a power supply chip, a filtering and voltage stabilizing circuit, a transformer, a first power transmission end, a first step-down circuit and a second power transmission end; The input end of the power chip is connected to the output end of the dual-varistor π-type filter module, and the output end of the power chip is connected to the input end of the filter voltage stabilization circuit; The output end of the filtering and voltage stabilizing circuit is connected to the main coil of the transformer, the main coil of the transformer is connected to the first power transmission end, and the first power transmission end is connected to the switch tube driving module; The input end of the first step-down circuit is connected to the first secondary coil of the transformer, the output end of the first step-down circuit is connected to the second power transmission end, and the second power transmission end is respectively connected to the control module and the thyristor driving module.

9. The control circuit of an induction cooker according to claim 8, characterized in that: The switching power supply module further includes: a second step-down circuit and a third power transmission terminal; The input end of the second step-down circuit is connected to the second secondary coil of the transformer, the output end of the second step-down circuit is connected to the third power transmission end, and the third power transmission end is connected to the thyristor driving module.

10. The control circuit of an induction cooker according to claim 1, characterized in that: The switch tube driving module includes: ACD-049 driving chip.

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