CN213213096U

CN213213096U - Secondary voltage surge protection circuit of special chip for electromagnetic oven

Info

Publication number: CN213213096U
Application number: CN202021848420.2U
Authority: CN
Inventors: 缪建斌; 胡川
Original assignee: CROWN RICH ELECTRONIC (SHENZHEN) CO LTD
Current assignee: CROWN RICH ELECTRONIC (SHENZHEN) CO LTD
Priority date: 2020-08-27
Filing date: 2020-08-27
Publication date: 2021-05-14
Anticipated expiration: 2030-08-27

Abstract

The utility model relates to a special chip secondary voltage surge protection circuit of electromagnetism stove. The secondary voltage surge protection circuit of the chip special for the induction cooker comprises a rectifying filter circuit, a wire coil resonance and driving circuit, an IGBT driving circuit, a synchronous circuit, a surge signal acquisition circuit and an MCU control chip, wherein the synchronous circuit comprises a back pressure acquisition circuit, and the MCU control chip comprises a CPU, a comparator COMP1, a comparator COMP2, a PPG control circuit and a first back pressure protection circuit. The application provides a special chip secondary voltage surge protection circuit of electromagnetism stove can let the IGBT be unlikely to because of the protection shut down when having less strong surge signal to arrive, can let the electromagnetism stove guarantee that the IGBT does not damage when having stronger surge signal to arrive again. Because the first-stage surge protection with higher sensitivity is provided, when a weaker surge signal arrives, the induction cooker can generate surge protection and cannot be shut down, so that an induction cooker manufacturer can improve the actual working back pressure of the IGBT as much as possible, and the actual power of the induction cooker is improved as much as possible.

Description

Secondary voltage surge protection circuit of special chip for electromagnetic oven

Technical Field

The utility model relates to an electromagnetism stove technical field especially relates to a special chip secondary voltage surge protection circuit of electromagnetism stove.

Background

At present, all special chips for induction cookers are provided with surge protection circuits, voltage surge protection and current surge protection are generally adopted, and the purpose of adopting the circuits is to start a protection mechanism in time when a surge signal arrives, so that all parameters of an IGBT do not exceed the standard.

However, at present, surge protection generally adopts only one stage, namely, the IGBT is immediately turned off when the surge comes. However, such a primary surge protection circuit has the following problems: if the surge protection is sensitive, the induction cooker is frequently shut down due to protection; if the surge protection is not sensitive, the induction cooker can have IGBT damage when a surge signal arrives. In order to prevent the damage of the IGBT, an induction cooker manufacturer usually intends to improve the sensitivity of surge protection or reduce the actual working back pressure of the IGBT, and if the induction cooker manufacturer increases the power of the induction cooker, the actual working back pressure of the IGBT is increased to be close to the maximum rated back pressure (for example, 1200V) of the IGBT, and the actual working back pressure of the IGBT may exceed the standard when a surge signal comes, so that the IGBT is damaged, which requires to improve the sensitivity of the surge protection, but this may cause the induction cooker to be shut down due to the surge protection.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to provide a special chip secondary voltage surge protection circuit of electromagnetism stove that can prevent when surge signal from arriving that the electromagnetism stove from shutting down because of the protection, can guarantee again that IGBT does not damage.

For realizing the purpose of the utility model, the utility model adopts the following technical scheme:

a secondary voltage surge protection circuit of a chip special for an induction cooker comprises a rectifying filter circuit, a wire coil resonance and driving circuit, an IGBT driving circuit, a synchronous circuit, a surge signal acquisition circuit and an MCU control chip, wherein the synchronous circuit comprises a back pressure acquisition circuit, and the MCU control chip comprises a CPU, a comparator COMP1, a comparator COMP2, a PPG control circuit and a first back pressure protection circuit;

the input end of the rectification filter circuit is connected with a live wire and a zero wire of an external alternating current power supply, the first output end of the rectification filter circuit is connected with the first input end of the wire coil resonance and driving circuit, and the output end of the wire coil resonance and driving circuit is connected with a wire coil of the induction cooker; a second output end of the rectification filter circuit is connected with a negative phase input end of the comparator COMP1 and a negative phase input end of the comparator COMP2 through the surge signal acquisition circuit respectively;

the output end of the wire coil resonance and driving circuit is connected with the input end of the synchronous circuit, and the output end of the synchronous circuit is respectively connected with the input end of the first back-pressure protection circuit and the first input end of the PPG control circuit; the input end of the CPU is connected to the output end of the first back-voltage protection circuit, the output end of the comparator COMP1, and the output end of the comparator COMP2, respectively; the output end of the CPU is connected to the positive-phase input end of the comparator COMP1, the positive-phase input end of the comparator COMP2, and the second input end of the PPG control circuit, respectively; a third input end of the PPG control circuit is connected to an output end of the first back-voltage protection circuit, an output end of the comparator COMP1, and an output end of the comparator COMP2, respectively; and the output end of the PPG control circuit is connected with the second input end of the wire coil resonance and driving circuit through the IGBT driving circuit.

Compare in traditional special chip of electromagnetism stove, the special chip secondary voltage surge protection circuit of electromagnetism stove that this application provided can let IGBT be unlikely to because of the protection shut down when having less strong surge signal to arrive, can let the electromagnetism stove stop power output when having stronger surge signal to arrive again, guarantees that IGBT does not damage. Because the first-stage surge protection with higher sensitivity is provided, when a weaker surge signal arrives, the induction cooker can generate surge protection and cannot be stopped (PPG output pulse width is greatly reduced), so that an induction cooker manufacturer can improve the actual working back pressure of the IGBT as much as possible, and the actual power of the induction cooker is improved as much as possible.

In one embodiment, the PPG control circuit includes a PPG generator, a PPG stop circuit, a PPG large reduction circuit, and a second back-pressure protection circuit, a first input terminal of the PPG generator is respectively connected to an output terminal of the PPG stop circuit, an output terminal of the PPG large reduction circuit, and an output terminal of the second back-pressure protection circuit, and an output terminal of the PPG generator is connected to a second input terminal of the wire coil resonance and driving circuit through the IGBT driving circuit;

the CPU comprises an MCU core component and an MCU interruption module, wherein the input end of the MCU interruption module is respectively connected with the output end of the comparator COMP1, the output end of the comparator COMP2 and the output end of the first back pressure protection circuit, and the output end of the MCU interruption module is connected with the input end of the MCU core component; the output end of the MCU core component is connected to the positive input end of the comparator COMP1, the positive input end of the comparator COMP2, the first input end of the PPG shutdown circuit, the first input end of the PPG large reduction circuit, the first input end of the second back-voltage protection circuit, and the second input end of the PPG generator, respectively; a second input end of the PPG stop circuit is connected to an output end of the comparator COMP 2; a second input end of the PPG amplitude reduction circuit is connected to an output end of the comparator COMP 1; a second input end of the second back-voltage protection circuit is connected with an output end of the first back-voltage protection circuit; and a third input end of the PPG generator is connected with an output end of the synchronous circuit.

In one embodiment, the rectifier filter circuit comprises an X capacitor C1, an X capacitor C2, a common-mode inductor T1, a choke coil L2 and a rectifier bridge stack BG1, wherein a first end of the X capacitor C1 and a first input end of the common-mode inductor T1 are both connected to the live line, a first output end of the common-mode inductor T1 is respectively connected to a first end of the X capacitor C2 and a first alternating current input end of the rectifier bridge stack BG1, and an anode of a direct current output end of the rectifier bridge stack BG1 is connected to a first end of the choke coil L2; the second end of the X capacitor C1 and the second input end of the common-mode inductor T1 are both connected with the zero line, the second output end of the common-mode inductor T1 is respectively connected with the second end of the X capacitor C2 and the second alternating current input end of the rectifier bridge stack BG1, and the negative electrode of the direct current output end of the rectifier bridge stack BG1 is grounded.

In one embodiment, the coil resonance and driving circuit comprises a capacitor C3, a capacitor C4, a resistor R1, a resistor R2 and an IGBT tube Q1, wherein a second end of the choke coil L2 is respectively connected with a first end of the capacitor C3, a first end of the capacitor C4 and a first end of the coil of the induction cooker, and a second end of the capacitor C3 is grounded; the second end of the induction cooker wire coil is respectively connected with the second end of the capacitor C4 and the collector of the IGBT tube Q1, the gate of the IGBT tube Q1 is respectively connected with the first end of the resistor R1 and the first end of the resistor R2, and the second end of the resistor R1 is grounded with the emitter of the IGBT tube Q1.

In one embodiment, the synchronization circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C5 and a capacitor C6, a first end of the resistor R3 is connected to a first end of the coil of the induction cooker, and a second end of the resistor R3 is connected to a first end of the resistor R5, a first end of the capacitor C5, a first end of the capacitor C6 and a third input end of the PPG generator, respectively; the first end of the resistor R4 is connected with the second end of the induction cooker wire coil, the second end of the resistor R4 is connected with the first end of the resistor R6, the second end of the capacitor C5, the third input end of the PPG generator and the input end of the first back-pressure protection circuit respectively, and the second end of the resistor R5, the second end of the resistor R6 and the second end of the capacitor C6 are all grounded.

In one embodiment, the IGBT driving circuit includes a transistor Q2, a transistor Q3, a transistor Q4, a diode D1, a resistor R7, a resistor R8, a resistor R9, a capacitor C7, and an electrolytic capacitor EC1, wherein a second terminal of the resistor R2 is respectively connected to an anode of the diode D1, an emitter of the transistor Q2, and an emitter of the transistor Q3, a cathode of the diode D1, a first terminal of the resistor R7, a first terminal of the resistor R8, a first terminal of the resistor R9, a first terminal of the capacitor C7, and an anode of the electrolytic capacitor EC1 are respectively connected to an 18V power supply, a second terminal of the resistor R7 is connected to a collector of the transistor Q2, a base of the transistor Q2 is respectively connected to a second terminal of the resistor R8, a base of the transistor Q3, a collector of the transistor Q4, and a base of the transistor Q4 is respectively connected to a second terminal of the resistor R9, The output end of the PPG generator is connected, and the collector of the triode Q3, the emitter of the triode Q4, the second end of the capacitor C7 and the negative electrode of the electrolytic capacitor EC1 are all grounded.

In one embodiment, the surge signal acquisition circuit comprises a diode D2, a diode D3, a resistor R10, a resistor R11, a resistor R12, a capacitor C8 and a capacitor C9, the anode of the diode D2 is connected to the first output terminal of the common mode inductor T1, the anode of the diode D3 is connected to the second output terminal of the common mode inductor T1, a cathode of the diode D2, a cathode of the diode D3, a first terminal of the resistor R10 and a first terminal of the capacitor C8 are connected in common, a first end of the resistor R11 is respectively connected with a second end of the resistor R10 and a second end of the capacitor C8, a second end of the resistor R11 is connected to the first end of the resistor R12, the first end of the capacitor C9, the non-inverting input terminal of the comparator COMP1, and the non-inverting input terminal of the comparator COMP2, respectively, and a second end of the resistor R12 and the second end of the capacitor C9 are grounded.

Drawings

FIG. 1 is a schematic diagram of a secondary voltage surge protection circuit of a chip dedicated for an induction cooker in an embodiment;

FIG. 2 is a schematic circuit diagram of a rectifying and filtering circuit according to an embodiment;

FIG. 3 is a schematic diagram of the electrical circuit of the coil resonance and actuation circuit in one embodiment;

FIG. 4 is a schematic circuit diagram of a synchronization circuit according to an embodiment;

FIG. 5 is a schematic circuit diagram of an IGBT driving circuit according to an embodiment;

fig. 6 is a schematic circuit diagram of a surge signal acquisition circuit in an embodiment.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the present invention are shown in the drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature.

Referring to fig. 1, the present embodiment provides a secondary voltage surge protection circuit of a chip dedicated for an induction cooker, including a rectifier filter circuit, a wire coil resonance and driving circuit, an IGBT driving circuit, a synchronization circuit, a surge signal acquisition circuit, and an MCU control chip, where the synchronization circuit includes a back voltage acquisition circuit, and the MCU control chip includes a CPU, a comparator COMP1, a comparator COMP2, a PPG control circuit, and a first back voltage protection circuit;

the input end of the rectification filter circuit is connected with a live wire (L) and a zero wire (N) of an external alternating current power supply, the first output end of the rectification filter circuit is connected with the first input end of the wire coil resonance and driving circuit, and the output end of the wire coil resonance and driving circuit is connected with a wire coil of the induction cooker; a second output end of the rectification filter circuit is respectively connected with a negative phase input end of a comparator COMP1 and a negative phase input end of a comparator COMP2 through the surge signal acquisition circuit;

the output end of the wire coil resonance and driving circuit is connected with the input end of the synchronous circuit, and the output end of the synchronous circuit is respectively connected with the input end of the first back-pressure protection circuit and the first input end of the PPG control circuit; the input end of the CPU is respectively connected with the output end of the first back-voltage protection circuit, the output end of the comparator COMP1 and the output end of the comparator COMP 2; the output end of the CPU is connected to the positive-phase input end of the comparator COMP1, the positive-phase input end of the comparator COMP2, and the second input end of the PPG control circuit, respectively; a third input end of the PPG control circuit is connected with an output end of the first back-voltage protection circuit, an output end of the comparator COMP1, and an output end of the comparator COMP2, respectively; the output end of the PPG control circuit is connected with the second input end of the wire coil resonance and driving circuit through the IGBT driving circuit.

The PPG control circuit comprises a PPG generator, a PPG stopping circuit, a PPG large reduction circuit and a second back pressure protection circuit, wherein a first input end of the PPG generator is respectively connected with an output end of the PPG stopping circuit, an output end of the PPG large reduction circuit and an output end of the second back pressure protection circuit, and an output end of the PPG generator is connected with a second input end of the wire coil resonance and driving circuit through an IGBT driving circuit;

the CPU comprises an MCU core component and an MCU interruption module, wherein the input end of the MCU interruption module is respectively connected with the output end of a comparator COMP1, the output end of a comparator COMP2 and the output end of the first back pressure protection circuit, and the output end of the MCU interruption module is connected with the input end of the MCU core component; the output end of the MCU core component is respectively connected with the positive phase input end of a comparator COMP1, the positive phase input end of a comparator COMP2, the first input end of a PPG stop circuit, the first input end of a PPG large reduction circuit, the first input end of a second back-voltage protection circuit and the second input end of a PPG generator; a second input end of the PPG stop circuit is connected to an output end of the comparator COMP 2; a second input end of the PPG large amplitude reduction circuit is connected with an output end of a comparator COMP 1; the second input end of the second back-voltage protection circuit is connected with the output end of the first back-voltage protection circuit; and a third input end of the PPG generator is connected with an output end of the synchronous circuit.

In the present embodiment, the non-inverting input terminal of the comparator COMP1 is connected to the reference voltage V1, the non-inverting input terminal of the comparator COMP2 is connected to the reference voltage V2, and V2> V1. The values of the three reference voltages V1 and V2 are controlled by the MCU core component, and the user can change the sizes of V1 and V2 in actual conditions.

The MCU core component can be used for controlling the start and stop of the pulse width of the PPG generator, sending the set value of the PPG pulse width to the PPG generator, and adjusting the reference voltages V1 and V2 at the positive phase input end of the 2 comparators. The PPG pulse width set value, which is loaded into the PPG generator at the falling edge of the output of comparator COMP2, is written to the PPG large reduction circuit. The MCU core component can also enable or close the PPG stopping circuit and determine whether the PPG stopping circuit can stop the PPG output of the PPG generator.

The MCU interrupt module is used for processing interrupt signals sent by the two comparators of the surge signal acquisition circuit and the first back-pressure protection circuit.

The PPG large reduction circuit is used for greatly reducing the pulse width of the PPG by sending a value far lower than the current PPG pulse width to the PPG generator when a weak surge signal comes and the surge acquisition voltage V exceeds V1 and outputting a falling edge signal to the PPG large reduction circuit by the comparator COMP 1; the PPG stopping circuit is used for outputting a falling edge signal to the PPG stopping circuit by the comparator COMP2 when a strong surge signal comes and the surge acquisition voltage V exceeds V2, and the pulse output of the PPG generator is immediately stopped by the circuit.

The surge protection process inside the MCU control chip is as follows:

when a weak surge signal comes, the surge acquisition voltage V exceeds V1, the output level of the comparator COMP1 is inverted by a falling edge, the falling edge signal is sent to a PPG large-amplitude reduction circuit on one hand, the PPG output pulse width is immediately and greatly reduced (a PPG pulse width set value far lower than the current PPG pulse width is sent to a PPG generator), and the back voltage of the next IGBT does not exceed the standard. On the other hand, the falling edge signal is sent to the MCU interruption module as an interruption signal, so that the MCU core component generates interruption, the MCU core component can recover normal power output in a short time, and the electromagnetic oven still continuously heats in the view of a user. The surge voltage protection is to add a first-stage surge pre-protection (greatly reduce PPG pulse width) in addition to the traditional surge voltage shutdown protection of the induction cooker so as to prevent the induction cooker from being frequently shut down.

When a strong surge signal comes, the surge acquisition voltage V exceeds V2, the output level of the comparator COMP2 is inverted by a falling edge, and the falling edge signal is sent to the PPG stop circuit to immediately turn off the PPG output. On the other hand, the falling edge signal is sent to the MCU interruption module, so that the MCU core component generates interruption, and the MCU core component restarts electromagnetic heating after delaying for several seconds. Namely, when a strong surge pulse comes, the induction cooker stops working for a few seconds and then starts heating.

Compare in traditional special chip of electromagnetism stove, the special chip secondary voltage surge protection circuit of electromagnetism stove that this embodiment provided can let the IGBT be unlikely to because of the protection shut down when having less strong surge signal to arrive, can let the electromagnetism stove stop power output when having stronger surge signal to arrive again, guarantees that the IGBT does not damage. Because the first-stage surge protection with higher sensitivity is provided, when a weaker surge signal arrives, the induction cooker can generate surge protection and cannot be stopped (PPG output pulse width is greatly reduced), so that an induction cooker manufacturer can improve the actual working back pressure of the IGBT as much as possible, and the actual power of the induction cooker is improved as much as possible.

In one embodiment, referring to fig. 2, the rectifier filter circuit includes an X capacitor C1, an X capacitor C2, a common mode inductor T1, a choke coil L2, and a rectifier bridge stack BG1, a first end of the X capacitor C1 and a first input end of the common mode inductor T1 are both connected to a live line (L), a first output end of the common mode inductor T1 is respectively connected to a first end of the X capacitor C2 and a first ac input end of the rectifier bridge stack BG1, and a positive electrode of a dc output end of the rectifier bridge stack BG1 is connected to a first end of the choke coil L2; the second end of the X capacitor C1 and the second input end of the common-mode inductor T1 are connected with a zero line (N), the second output end of the common-mode inductor T1 is connected with the second end of the X capacitor C2 and the second alternating current input end of the rectifier bridge stack BG1 respectively, and the negative electrode of the direct current output end of the rectifier bridge stack BG1 is grounded.

In the embodiment, commercial power coming from a live line (L) and a neutral line (N) is filtered by an X capacitor C1, a common mode inductor T1 and an X capacitor C2 to form L1 and N1, and then is rectified by a rectifier bridge stack BG1 and filtered by a choke coil L2, and then is supplied to a coil resonance and driving circuit.

In one embodiment, referring to fig. 3, the coil resonance and driving circuit comprises a capacitor C3, a capacitor C4, a resistor R1, a resistor R2 and an IGBT tube Q1, wherein a second end of a choke coil L2 is respectively connected with a first end of a capacitor C3, a first end of a capacitor C4 and a first end of a coil of the induction cooker, and a second end of a capacitor C3 is grounded; the second end of the induction cooker wire coil is respectively connected with the second end of the capacitor C4 and the collector of the IGBT tube Q1, the gate of the IGBT tube Q1 is respectively connected with the first end of the resistor R1 and the first end of the resistor R2, and the second end of the resistor R1 is grounded with the emitter of the IGBT tube Q1.

In this embodiment, the coil connected to the ports of COL1 and COL2 forms a parallel resonant circuit with the capacitor C4. Q1 is an IGBT for energizing the resonant tank.

In one embodiment, referring to fig. 4, the synchronization circuit includes a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C5, and a capacitor C6, a first end of the resistor R3 is connected to a first end of a coil of the induction cooker, and a second end of the resistor R3 is connected to a first end of the resistor R5, a first end of the capacitor C5, a first end of the capacitor C6, and a third input terminal of the PPG generator, respectively; the first end of the resistor R4 is connected with the second end of the wire coil of the induction cooker, the second end of the resistor R4 is respectively connected with the first end of the resistor R6, the second end of the capacitor C5, the third input end of the PPG generator and the input end of the first back-pressure protection circuit, and the second end of the resistor R5, the second end of the resistor R6 and the second end of the capacitor C6 are all grounded.

In this embodiment, voltages V _ DC and V _ IGBT _ C at two ends of the wire coil are divided by a resistor R3, a resistor R4, a resistor R5 and a resistor R6 to form a SYNC _ N signal and a SYNC _ P signal, and the SYNC _ N signal and the SYNC _ P signal are used as synchronization signals to be sent to the MCU core component, so that the driving signals of the IGBTs and the wire coil resonance are synchronized. Meanwhile, one end of the wire coil is connected with a collector (C pole) of the IGBT, the voltage of the C pole is the back pressure V _ IGBT _ C, the SYNC _ P signal formed after the back pressure V _ IGBT _ C is divided by the resistor R4 and the resistor R6 is also the back pressure acquisition signal V _ C, and the signal is sent to a first back pressure protection circuit inside the MCU control chip.

In one embodiment, referring to fig. 5, the IGBT driver circuit includes a transistor Q2, a transistor Q3, a transistor Q4, a diode D1, a resistor R7, a resistor R8, a resistor R9, a capacitor C7, and an electrolytic capacitor EC1, wherein a second terminal of the resistor R2 is connected to an anode of the diode D1, an emitter of the transistor Q2, and an emitter of the transistor Q3, respectively, a cathode of the diode D3, a first terminal of the resistor R3, a first terminal of the capacitor C3, and a positive terminal of the electrolytic capacitor EC 3 are connected to an 18V power supply, a second terminal of the resistor R3 is connected to a collector of the transistor Q3, a base of the transistor Q3 is connected to a second terminal of the resistor R3, a base of the transistor Q3, a collector of the transistor PPG, and a second terminal of the transistor, The second end of the capacitor C7 and the negative electrode of the electrolytic capacitor EC1 are both grounded.

In this embodiment, a PPG signal from the PPG generator is inverted by the transistor Q4, and then is followed by the emitter of the transistor Q2 and the emitter of the transistor Q3 to drive the IGBT to operate.

In one embodiment, referring to fig. 6, the surge signal collecting circuit includes a diode D2, a diode D3, a resistor R10, a resistor R11, a resistor R12, a capacitor C8 and a capacitor C9, an anode of the diode D2 is connected to a first output terminal of the common mode inductor T1, an anode of the diode D3 is connected to a second output terminal of the common mode inductor T1, a cathode of the diode D2, a cathode of the diode D3 and a first end of the resistor R10 are connected to a first end of the capacitor C8, a first end of the resistor R11 is connected to a second end of the resistor R10 and a second end of the capacitor C8, a second end of the resistor R11 is connected to a first end of the resistor R12, a first end of the capacitor C9, a positive phase input terminal of the comparator COMP1 and a positive phase input terminal of the comparator COMP2, and a second end of the resistor R12 is connected to a second end of the capacitor C9.

In this embodiment, the live line (L) and the neutral line (N) are rectified by the diode D2 and the diode D3, and are divided by the resistor R10, the resistor R11, and the resistor R12 to form a surge collecting signal V, which is sent to 2 comparators inside the MCU control chip. The capacitor C8 is used for passing high frequency and blocking low frequency, so that surge signals can pass; the function of the capacitor C9 is filtering.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent some embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. A secondary voltage surge protection circuit of a chip special for an induction cooker is characterized by comprising a rectifying filter circuit, a wire coil resonance and driving circuit, an IGBT driving circuit, a synchronous circuit, a surge signal acquisition circuit and an MCU control chip, wherein the synchronous circuit comprises a back voltage acquisition circuit, and the MCU control chip comprises a CPU, a comparator COMP1, a comparator COMP2, a PPG control circuit and a first back voltage protection circuit;

2. The secondary voltage surge protection circuit of the chip special for the induction cooker according to claim 1, wherein the PPG control circuit comprises a PPG generator, a PPG stop circuit, a PPG great reduction circuit and a second back-voltage protection circuit, a first input end of the PPG generator is respectively connected with an output end of the PPG stop circuit, an output end of the PPG great reduction circuit and an output end of the second back-voltage protection circuit, and an output end of the PPG generator is connected with a second input end of the wire coil resonance and driving circuit through the IGBT driving circuit;

3. The chip secondary voltage surge protection circuit special for the induction cooker according to claim 2, wherein the rectifier filter circuit comprises an X capacitor C1, an X capacitor C2, a common-mode inductor T1, a choke coil L2 and a rectifier bridge stack BG1, a first end of the X capacitor C1 and a first input end of the common-mode inductor T1 are both connected to the live wire, a first output end of the common-mode inductor T1 is respectively connected to a first end of the X capacitor C2 and a first alternating current input end of the rectifier bridge stack BG1, and a positive electrode of a direct current output end of the rectifier bridge stack BG1 is connected to a first end of the choke coil L2; the second end of the X capacitor C1 and the second input end of the common-mode inductor T1 are both connected with the zero line, the second output end of the common-mode inductor T1 is respectively connected with the second end of the X capacitor C2 and the second alternating current input end of the rectifier bridge stack BG1, and the negative electrode of the direct current output end of the rectifier bridge stack BG1 is grounded.

4. The induction cooker dedicated chip secondary voltage surge protection circuit according to claim 3, wherein the coil resonance and driving circuit comprises a capacitor C3, a capacitor C4, a resistor R1, a resistor R2 and an IGBT tube Q1, a second end of the choke coil L2 is respectively connected with a first end of the capacitor C3, a first end of the capacitor C4 and a first end of the induction cooker coil, and a second end of the capacitor C3 is grounded; the second end of the induction cooker wire coil is respectively connected with the second end of the capacitor C4 and the collector of the IGBT tube Q1, the gate of the IGBT tube Q1 is respectively connected with the first end of the resistor R1 and the first end of the resistor R2, and the second end of the resistor R1 is grounded with the emitter of the IGBT tube Q1.

5. The secondary voltage surge protection circuit of claim 4, wherein the synchronization circuit comprises a resistor R3, a resistor R4, a resistor R5, a resistor R6, a capacitor C5 and a capacitor C6, a first end of the resistor R3 is connected to a first end of the coil of the induction cooker, and a second end of the resistor R3 is connected to a first end of the resistor R5, a first end of the capacitor C5, a first end of the capacitor C6 and a third input end of the PPG generator respectively; the first end of the resistor R4 is connected with the second end of the induction cooker wire coil, the second end of the resistor R4 is connected with the first end of the resistor R6, the second end of the capacitor C5, the third input end of the PPG generator and the input end of the first back-pressure protection circuit respectively, and the second end of the resistor R5, the second end of the resistor R6 and the second end of the capacitor C6 are all grounded.

6. The two-stage voltage surge protection circuit of chip dedicated for electromagnetic oven of claim 5, wherein said IGBT driving circuit comprises a transistor Q2, a transistor Q3, a transistor Q4, a diode D1, a resistor R7, a resistor R8, a resistor R9, a capacitor C7 and an electrolytic capacitor EC1, wherein a second terminal of said resistor R2 is connected to an anode of said diode D1, an emitter of said transistor Q2 and an emitter of said transistor Q3, respectively, a cathode of said diode D1, a first terminal of said resistor R7, a first terminal of said resistor R8, a first terminal of said resistor R9, a first terminal of said capacitor C7 and an anode of said electrolytic capacitor EC1 are all connected to an 18V power supply, a second terminal of said resistor R7 is connected to a collector of said transistor Q2, a base of said transistor Q2 is connected to a second terminal of said resistor R8, a base of said transistor Q3, respectively, The collector of the triode Q4 is connected, the base of the triode Q4 is respectively connected with the second end of the resistor R9 and the output end of the PPG generator, and the collector of the triode Q3, the emitter of the triode Q4, the second end of the capacitor C7 and the negative electrode of the electrolytic capacitor EC1 are all grounded.

7. The secondary voltage surge protection circuit of the chip dedicated for the induction cooker according to claim 6, wherein said surge signal collecting circuit comprises a diode D2, a diode D3, a resistor R10, a resistor R11, a resistor R12, a capacitor C8 and a capacitor C9, an anode of said diode D2 is connected to a first output terminal of said common mode inductor T1, an anode of said diode D3 is connected to a second output terminal of said common mode inductor T1, a cathode of said diode D2, a cathode of said diode D3, a first terminal of said resistor R10 is connected to a first terminal of said capacitor C8, a first terminal of said resistor R11 is connected to a second terminal of said resistor R10 and a second terminal of said capacitor C8, a second terminal of said resistor R11 is connected to a first terminal of said resistor R12, a first terminal of said capacitor C9, an input terminal of said comparator COMP1, and a positive phase input terminal of said comparator COMP2, the second end of the resistor R12 and the second end of the capacitor C9 are grounded.