CN106714350B

CN106714350B - Electromagnetic heating control system of system on chip

Info

Publication number: CN106714350B
Application number: CN201510452018.XA
Authority: CN
Inventors: 刘志才; 王志锋; 马志海; 陈逸凡; 区达理
Original assignee: Midea Group Co Ltd; Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Current assignee: Midea Group Co Ltd; Foshan Shunde Midea Electrical Heating Appliances Manufacturing Co Ltd
Priority date: 2015-07-28
Filing date: 2015-07-28
Publication date: 2023-03-24
Anticipated expiration: 2035-07-28
Also published as: CN106714350A

Abstract

The invention discloses an electromagnetic heating control system of an on-chip system, which comprises a mains supply input end, a resonance circuit, an IGBT (insulated gate bipolar transistor) driving circuit, an MCU (microprogrammed control unit) and a switching power supply circuit, wherein the input end of the mains supply is connected with the resonance circuit; the resonance circuit comprises an IGBT tube; an IGBT voltage extreme value detection circuit and a PWM generation circuit are arranged inside the MCU; the resonance circuit is used for performing resonance heating on the electromagnetic heating device; the IGBT tube is used for controlling the heating state of the resonance circuit; the switching power supply circuit is used for supplying power to the MCU and the IGBT driving circuit; the IGBT driving circuit is used for driving the resonant circuit to work; the IGBT voltage extreme value detection circuit is used for detecting a voltage extreme value of a collector of the IGBT tube; and the PWM generating circuit is used for outputting a corresponding PWM signal according to the detection result of the IGBT voltage extreme value detection circuit so as to control the switching action of the IGBT tube. The invention has the advantages of low loss and high reliability.

Description

Electromagnetic heating control system of system on chip

Technical Field

The invention relates to the field of control, in particular to an electromagnetic heating control system of an on-chip system.

Background

In an electromagnetic heating control system in the prior art, a triggering conduction mode of an IGBT tube for controlling a heating state of the system in the system is usually a synchronous triggering conduction mode, and the synchronous triggering conduction mode has the following defects: when the electromagnetic heating control system is in a low-power heating state (namely when the conduction pulse width of the IGBT tube is small) or the mains voltage is high, the IGBT tube is conducted (hard on) under a certain voltage, and when the IGBT tube is conducted under a certain voltage, the turn-on loss of the IGBT tube is large; moreover, when the IGBT is turned on at a certain voltage, the temperature rise of the IGBT is high, which may cause a reduction in the service life of the IGBT.

Referring to fig. 1, fig. 1 is a schematic circuit structure diagram of an embodiment of an electromagnetic heating control system in the prior art, where the electromagnetic heating control system includes a power input terminal 101, an IGBT drive circuit 102, an MCU a11, a heating coil disc LH1, an IGBT tube Q1, a capacitor C2, a capacitor C3, a resonant capacitor C4, a resistor R11, a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a resistor R17, a resistor R18, a resistor R19, a resistor R20, a resistor RK1, and a diode D11. The MCU A11 comprises a voltage comparator A11-U1 and a PWM generating module A11-U2 inside, and the power input by the power input end 101 is rectified mains supply. Specifically, the first end OUT11 of the heating coil disc LH1 and the first end of the resonant capacitor C4 are both connected to the power input terminal 101, and the second end of the resonant capacitor C4 is connected to the second end OUT12 of the heating coil disc LH1 and the collector C of the IGBT tube Q1, respectively; a first end of the resistor R11 is connected with a first end of the resonant capacitor C4, a second end of the resistor R11 is connected with a first end of the resistor R15 through a resistor R12, a resistor R13 and a resistor R14 which are connected in series, and a second end of the resistor R15 is grounded through a resistor R16; the first end of the capacitor C1 is connected with the first end of the resistor R15, and the second end of the capacitor C1 is grounded; the first end of the resistor R15 is also connected with the non-inverting input end of a voltage comparator A11-U1 in the MCU A11; a first end of the resistor R17 is connected with a second end of the resonant capacitor C4, a second end of the resistor R17 is connected with a first end of the resistor R19 through a resistor R18, and a second end of the resistor R19 is grounded through a resistor R20; the first end of the capacitor C3 is connected with the first end of the resistor R19, and the second end of the capacitor C3 is grounded; a first end of the capacitor C2 is connected with a first end of the resistor R15, and a second end of the capacitor C2 is connected with a first end of the resistor R19; the anode of the diode D11 is connected to the first end of the resistor R19, and the cathode of the diode D11 is grounded; the first end of the resistor R19 is also connected with the inverting input end of a voltage comparator A11-U1 in the MCU A11; the output end of a voltage comparator A11-U1 in the MCU A11 is connected with the input end of a PWM generating module A11-U2, and the output end of the PWM generating module A11-U2 is connected with the input end of the IGBT driving circuit 102; the output end of the IGBT driving circuit 102 is connected with a gate electrode G of an IGBT tube Q1; the emitter E of the IGBT tube Q1 is grounded through a resistor RK 1.

In the electromagnetic heating control system shown in fig. 1, the triggering and conducting mode for the IGBT Q1 is a synchronous triggering and conducting mode, and the working principle is as follows: when the IGBT tube Q1 is turned on, a current flows from the first end OUT11 of the heating coil disc LH1 to the second end OUT12 of the heating coil disc LH1, at this time, a voltage signal Va obtained by dividing a voltage at the first end (lower end) of the resonant capacitor C4 by the resistor R11, the resistor R12, the resistor R13, the resistor R14, the resistor R15, and the resistor R16 is input to the non-inverting input terminal of the voltage comparator a11-U1 inside the MCU a11, a voltage at the second end (upper end) of the resonant capacitor C4 is input to the inverting input terminal of the voltage comparator a11-U1 inside the MCU a11 by the resistor R17, the resistor R18, the resistor R19, and the resistor R20, at this time, a voltage at the lower end of the resonant capacitor C4 is clamped to a voltage at the power supply input terminal 101 (i.e., a mains voltage), and a voltage at the upper end of the resonant capacitor C4 is pulled to the ground level by the IGBT tube Q1, at this time, i.e., the voltage Va > Vb; when the IGBT tube Q1 is turned off, the current of the heating coil disc LH1 cannot suddenly change due to the inductance effect of the heating coil disc LH1, and the current continues to flow from the first end OUT11 of the heating coil disc LH1 to the second end OUT12 of the heating coil disc LH1 and charges the resonant capacitor C4, so that the voltage at the upper end of the resonant capacitor C4 continuously rises until the current on the heating coil disc LH1 is completely released. When the current of the heating coil disc LH1 is 0, the voltage at the upper end of the resonant capacitor C4 reaches the maximum, and the voltage Va < the voltage Vb. When the voltage Va < the voltage Vb, the resonant capacitor C4 starts to discharge to the heating coil disc LH1, and at this time, a current flows from the second terminal OUT12 of the heating coil disc LH1 to the first terminal OUT11 of the heating coil disc LH1 until the discharge of the electric power of the resonant capacitor C4 is completed (when the discharge of the electric power of the resonant capacitor C4 is completed, the lower-end voltage of the resonant capacitor C4 is equal to the upper-end voltage thereof). When the electric energy of the resonant capacitor C4 is released, the current still flows from the upper end to the lower end on the heating coil disc LH1, at this time, the voltage at the lower end of the resonant capacitor C4 is clamped at the mains voltage, the voltage at the upper end of the resonant capacitor C4 is continuously pulled down, and when the voltage Vb is smaller than the voltage Va, a pulse signal with a rising edge is generated at the output end of the voltage comparator a11-U1, and the pulse signal with the rising edge triggers the PWM generation module a11-U2 to generate a conduction pulse width for conducting the IGBT tube Q1. Thereafter, the above steps are repeated. In the electromagnetic heating control system shown in fig. 1, since the IGBT Q1 is triggered and conducted synchronously, when the electromagnetic heating control system is in a low-power heating state or when the mains voltage is high, the turn-on loss of the IGBT Q1 is large, and the service life of the IGBT Q1 is reduced.

Disclosure of Invention

The invention mainly aims to provide an electromagnetic heating control system of a system on chip, which has low power consumption and high reliability.

In order to achieve the above object, the present invention provides an electromagnetic heating control system of a system on chip, the electromagnetic heating control system of the system on chip is used for controlling the resonant heating operation of an electromagnetic heating device, and the electromagnetic heating control system of the system on chip comprises a mains supply input end, a first rectifying and filtering circuit, a second rectifying and filtering circuit, a resonant circuit, an IGBT driving circuit, an MCU and a switching power supply circuit; the resonance circuit comprises an IGBT tube; an IGBT voltage extreme value detection circuit and a PWM generation circuit are arranged in the MCU; wherein,

the first rectifying and filtering circuit is used for rectifying and filtering a mains supply and supplying power to the resonant circuit;

the second rectification filter circuit is used for rectifying and filtering the mains supply and supplying power to the switch power supply circuit;

the resonant circuit is used for carrying out resonant heating on the electromagnetic heating device; the IGBT tube is used for controlling the heating state of the resonance circuit;

the switching power supply circuit is used for supplying power to the MCU and the IGBT driving circuit;

the IGBT driving circuit is used for driving the resonant circuit to work;

the MCU is used for controlling the heating work of the resonance circuit; the IGBT voltage extreme value detection circuit is used for detecting the voltage extreme value of the collector of the IGBT tube; and the PWM generating circuit is used for outputting a corresponding PWM signal to the IGBT driving circuit according to the detection result of the IGBT voltage extreme value detection circuit so as to control the switching action of the IGBT tube.

Preferably, the input end of the first rectifying and filtering circuit and the input end of the second rectifying and filtering circuit are both connected with the input end of the mains supply, the output end of the first rectifying and filtering circuit is connected with the power input end of the resonance circuit, and the output end of the second rectifying and filtering circuit is connected with the input end of the switching power supply circuit; the output end of the switching power supply circuit is respectively connected with the power supply end of the MCU and the power supply end of the IGBT driving circuit; the input end of the IGBT driving circuit is connected with the output end of the PWM generating circuit, and the output end of the IGBT driving circuit is connected with the driving control input end of the resonance circuit; the detection input end of the IGBT voltage extreme value detection circuit is connected with the collector of the IGBT tube, and the detection output end of the IGBT voltage extreme value detection circuit is connected with the input end of the PWM generation circuit.

Preferably, the electromagnetic heating control system of the system on chip further includes a mains supply zero-crossing detection circuit for detecting a zero-crossing point of a mains supply; the detection input end of the commercial power zero-crossing detection circuit is connected with the output end of the second rectification filter circuit, the detection output end of the commercial power zero-crossing detection circuit is connected with the first signal input end of the MCU, and the MCU shields the detection output function of the IGBT voltage extreme value detection circuit and controls the PWM generation circuit to output PWM signals with preset duty ratio and preset frequency to the IGBT driving circuit in a preset time period so as to control the switching action of the IGBT tube when the commercial power zero-crossing detection circuit detects the zero crossing of the commercial power supply.

Preferably, a detection input end of the IGBT voltage extreme value detection circuit is connected to a collector of the IGBT in the resonant circuit, a detection output end of the IGBT voltage extreme value detection circuit is connected to an input end of the PWM generation circuit, and the IGBT voltage extreme value detection circuit controls the PWM generation circuit to output a conduction pulse width for turning on the IGBT when detecting that a voltage of the collector of the IGBT is a lowest point voltage.

Preferably, the IGBT voltage extreme value detection circuit includes a voltage division circuit unit and an active differentiation circuit unit; wherein,

the input end of the voltage division circuit unit is connected with the collector electrode of the IGBT tube, and the output end of the voltage division circuit unit is connected with the input end of the active differential circuit unit; and the output end of the active differential circuit unit is connected with the input end of the PWM generating circuit.

Preferably, the active differential circuit unit includes a first working voltage input terminal, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, and a first voltage comparator inside the MCU; wherein,

the first end of the first capacitor is connected with the output end of the voltage division circuit unit, and the second end of the first capacitor is connected with the first end of the second resistor through the first resistor; the second end of the second resistor is connected with the output end of the first voltage comparator; the output end of the first voltage comparator is also connected with the input end of the PWM generating circuit; the second capacitor is connected with the second resistor in parallel; the first end of the second resistor is also connected with the inverting input end of the first voltage comparator; the non-inverting input end of the first voltage comparator is respectively connected with the first end of the third resistor and the first end of the fourth resistor; the second end of the third resistor is connected with the first working voltage input end; and the second end of the fourth resistor is grounded.

Preferably, the PWM generation circuit includes a fifth resistor, a sixth resistor, a second voltage comparator inside the MCU, an and gate inside the MCU, and a PWM generation module inside the MCU; wherein,

the non-inverting input end of the second voltage comparator is connected with the output end of the first voltage comparator, and the inverting input end of the second voltage comparator is respectively connected with the first end of the fifth resistor and the first end of the sixth resistor; a second end of the fifth resistor is connected with the first working voltage input end; a second end of the sixth resistor is grounded; the output end of the second voltage comparator is connected with the first input end of the AND gate; the first input end of the AND gate is connected with the output end of the PWM generating module; the output end of the AND gate is connected with the input end of the PWM generating module; and the output end of the PWM generation module is also connected with the input end of the IGBT driving circuit.

Preferably, the electromagnetic heating control system of the system on chip further includes a mains voltage detection circuit for detecting a voltage of the mains power supply, an IGBT current detection circuit for detecting a current of the IGBT tube, and an IGBT overvoltage detection circuit for detecting whether a collector voltage of the IGBT tube is overvoltage; the detection input end of the mains supply voltage detection circuit is connected with the output end of the second rectification filter circuit, and the detection output end of the mains supply voltage detection circuit is connected with the second signal input end of the MCU; the detection input end of the IGBT current detection circuit is connected with the current output end of the IGBT tube, and the detection output end of the IGBT current detection circuit is connected with the third signal input end of the MCU; the detection input end of the IGBT overvoltage detection circuit is connected with the collector electrode of the IGBT tube, and the detection output end of the IGBT overvoltage detection circuit is connected with the fourth signal input end of the MCU.

Preferably, the electromagnetic heating control system of the system on chip further includes a keypad communication interface circuit for inputting a power setting value of the electromagnetic heating device and a mains supply surge detection circuit for detecting a surge of the mains supply; the power end of the keypad communication interface circuit is connected with the switching power supply circuit, and the output end of the keypad communication interface circuit is connected with the fifth signal input end of the MCU; and the detection input end of the mains supply surge detection circuit is connected with the output end of the second rectifying and filtering circuit, and the detection output end of the mains supply surge detection circuit is connected with the sixth signal input end of the MCU.

Preferably, the electromagnetic heating control system of the system on chip further includes an alarm device for emitting an alarm sound when the mains voltage detected by the mains voltage detection circuit is greater than a preset mains voltage value, the current detected by the IGBT current detection circuit is greater than a preset current value, the collector voltage of the IGBT tube detected by the IGBT overvoltage detection circuit is greater than a preset collector voltage value, or the mains surge detected by the mains surge detection circuit is greater than a preset surge value; the power end of the alarm device is connected with the switching power supply circuit, and the control input end of the alarm device is connected with the MCU.

The invention provides an electromagnetic heating control system of a system on chip, which is used for controlling the resonant heating work of an electromagnetic heating device, and comprises a mains supply input end, a first rectifying and filtering circuit, a second rectifying and filtering circuit, a resonant circuit, an IGBT (insulated gate bipolar transistor) driving circuit, an MCU (microprogrammed control unit) and a switching power supply circuit; the resonance circuit comprises an IGBT tube; an IGBT voltage extreme value detection circuit and a PWM generation circuit are arranged in the MCU; the first rectifying and filtering circuit is used for rectifying and filtering a mains supply and supplying power to the resonant circuit; the second rectification filter circuit is used for rectifying and filtering the mains supply and supplying power to the switch power supply circuit; the resonant circuit is used for carrying out resonant heating on the electromagnetic heating device; the IGBT tube is used for controlling the heating state of the resonance circuit; the switching power supply circuit is used for supplying power to the MCU and the IGBT driving circuit; the IGBT driving circuit is used for driving the resonant circuit to work; the MCU is used for controlling the heating work of the resonance circuit; the IGBT voltage extreme value detection circuit is used for detecting the voltage extreme value of the collector of the IGBT tube; and the PWM generating circuit is used for outputting a corresponding PWM signal to the IGBT driving circuit according to the detection result of the IGBT voltage extreme value detection circuit so as to control the switching action of the IGBT tube. The electromagnetic heating control system of the system on chip provided by the invention has the advantages of low power loss and high reliability; meanwhile, the electromagnetic heating control system of the system on chip also has the advantages of simple circuit structure and easy realization.

Drawings

FIG. 1 is a schematic diagram of a circuit configuration of an embodiment of a prior art electromagnetic heating control system;

FIG. 2 is a block diagram of an exemplary embodiment of a system-on-chip electromagnetic heating control system;

FIG. 3 is a schematic diagram of a circuit connection structure among an IGBT voltage extreme value detection circuit, a PWM generation circuit, a resonance circuit and an IGBT driving circuit in an embodiment of an electromagnetic heating control system of a system on a chip according to the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides an electromagnetic heating control system of a system on a chip.

Referring to fig. 2, fig. 2 is a schematic block diagram of an embodiment of an electromagnetic heating control system of a system on chip according to the present invention.

In this embodiment, the electromagnetic heating control system of the system on chip is used to control the resonant heating operation of the electromagnetic heating device. The electromagnetic heating control system of the system on chip of this embodiment includes a mains power input 201, a first rectifying and filtering circuit 202, a second rectifying and filtering circuit 203, a resonant circuit 204, an MCU205, a switching power supply circuit 206, and an IGBT driving circuit 207.

The mains supply input end 201 is used for inputting a mains supply and providing power supply for the electromagnetic heating control system of the system on chip in this embodiment;

the first rectifying and filtering circuit 202 is configured to rectify and filter the mains supply input by the mains supply input end 201 and provide a supply voltage for the resonant circuit 204;

the second rectifying and filtering circuit 203 is configured to rectify and filter the mains power input by the mains power input end 201 and provide a supply voltage for the switching power supply circuit 206;

the resonant circuit 204 is used for performing resonant heating on the electromagnetic heating device;

the MCU205 is configured to control heating operation of the resonant circuit 204;

the switching power supply circuit 206 is configured to provide a power supply voltage for the electromagnetic heating control system of the system on chip in this embodiment, that is, the power supply voltage of the MCU205 and the power supply voltage of the IGBT driving circuit 207 are both provided by the switching power supply circuit 206;

the IGBT driving circuit 207 is configured to drive the resonant circuit 204 to operate.

In this embodiment, the resonant circuit 204 includes an IGBT tube (not shown) for controlling a heating state of the resonant circuit 204; an IGBT voltage extreme value detection circuit 2051 for detecting the voltage extreme value of the collector of the IGBT tube and a PWM generation circuit 2052 for outputting a corresponding PWM signal to the IGBT drive circuit 207 according to the detection result of the IGBT voltage extreme value detection circuit 2051 to control the switching action of the IGBT tube in the resonant circuit 204 are arranged inside the MCU 205.

Specifically, in this embodiment, the input end of the first rectifying and filtering circuit 202 and the input end of the second rectifying and filtering circuit 203 are both connected to the mains power input end 201, the output end of the first rectifying and filtering circuit 202 is connected to the power input end of the resonant circuit 204, and the output end of the second rectifying and filtering circuit 203 is connected to the input end of the switching power supply circuit 206; the output end of the switching power supply circuit 206 is respectively connected with the power supply end of the MCU205 and the power supply end of the IGBT driving circuit 207; the input end of the IGBT driving circuit 207 is connected to the output end of the PWM generating circuit 2052, and the output end of the IGBT driving circuit 206 is connected to the driving control input end of the resonant circuit 204; the detection input end of the IGBT voltage extreme value detection circuit 2051 is connected to the collector of the IGBT element in the resonant circuit 204, and the detection output end of the IGBT voltage extreme value detection circuit 2051 is connected to the input end of the PWM generation circuit 2052.

Further, the electromagnetic heating control system of the system-on-chip of the embodiment further includes a commercial power zero-crossing detection circuit 208, where the commercial power zero-crossing detection circuit 208 is configured to detect a zero-crossing point of a commercial power supply. Specifically, a detection input end of the commercial power zero-crossing detection circuit 208 is connected to an output end of the second rectifying and filtering circuit 203, and a detection output end of the commercial power zero-crossing detection circuit 208 is connected to a first signal input end of the MCU 205.

Further, the electromagnetic heating control system of the system on chip of this embodiment further includes a mains voltage detection circuit 209, and the mains voltage detection circuit 209 is configured to detect a voltage of the mains power supply. Specifically, the detection input end of the mains voltage detection circuit 209 is connected to the output end of the second rectifying and filtering circuit 203, and the detection output end of the mains voltage detection circuit 209 is connected to the second signal input end of the MCU 205.

Further, the electromagnetic heating control system of the system on chip of the present embodiment further includes an IGBT current detection circuit 210 and an IGBT overvoltage detection circuit 211;

the IGBT current detection circuit 210 is configured to detect a current of the IGBT in the resonant circuit 204;

and the IGBT overvoltage detection circuit 211 is used for detecting whether the voltage of the collector of the IGBT tube is overvoltage or not.

Specifically, the detection input end of the IGBT current detection circuit 210 is connected to the current output end of the IGBT tube in the resonant circuit 204, and the detection output end of the IGBT current detection circuit 210 is connected to the third signal input end of the MCU 205; the detection input end of the IGBT overvoltage detection circuit 211 is connected to the collector of the IGBT in the resonant circuit 204, and the detection output end of the IGBT overvoltage detection circuit 211 is connected to the fourth signal input end of the MCU 205.

Further, the electromagnetic heating control system of the system on chip of the present embodiment further includes a keypad communication interface circuit 215, where the keypad communication interface circuit 215 is configured to input a power setting value of the electromagnetic heating apparatus. A power terminal of the keypad communication interface circuit 215 is connected to the switching power circuit 206 (i.e., the power supply voltage of the keypad communication interface circuit 215 is provided by the switching power circuit 206), and an output terminal of the keypad communication interface circuit 215 is connected to the fifth signal input terminal of the MCU 205.

Further, the electromagnetic heating control system of the system on chip of the present embodiment further includes a mains surge detection circuit 216, where the mains surge detection circuit 216 is configured to detect a surge of a mains power supply. The detection input end of the mains surge detection circuit 216 is connected with the output end of the second rectifying and filtering circuit 203, and the detection output end of the mains surge detection circuit 216 is connected with the sixth signal input end of the MCU 205.

Further, the electromagnetic heating control system of the system on chip of this embodiment further includes an IGBT temperature detection circuit 212, a furnace temperature detection circuit 213, and a fan drive circuit 214;

the IGBT temperature detection circuit 212 is configured to detect the temperature of the IGBT in the resonant circuit 205;

the furnace temperature detection circuit 213 is configured to detect a furnace temperature of the electromagnetic heating device;

the fan driving circuit 214 is configured to control the rotation speed of a fan in the electromagnetic heating device according to the detection results of the IGBT temperature detection circuit 212 and the furnace temperature detection circuit 213, so as to adjust the temperature of the electromagnetic heating device.

Specifically, the power end of the IGBT temperature detection circuit 212, the power end of the furnace temperature detection circuit 213, and the power end of the fan drive circuit 214 are all connected to the switching power supply circuit 206 (that is, the power supply voltage of the IGBT temperature detection circuit 212, the power supply voltage of the furnace temperature detection circuit 213, and the power supply voltage of the fan drive circuit 214 are all provided by the switching power supply circuit 206), the detection output end of the IGBT temperature detection circuit 212 is connected to the seventh signal input end of the MCU205, and the detection output end of the furnace temperature detection circuit 213 is connected to the eighth signal input end of the MCU 205; the input end of the fan driving circuit 214 is connected with the control signal output end of the MCU205, and the output end of the fan driving circuit 214 is connected with the control input end of the fan in the electromagnetic heating device.

Further, the electromagnetic heating control system of the system on chip of the present embodiment further includes an alarm device 217. In this embodiment, when the utility voltage detected by the utility voltage detection circuit 209 is greater than a preset utility voltage value, the current detected by the IGBT current detection circuit 210 is greater than a preset current value, the collector voltage of the IGBT tube detected by the IGBT overvoltage detection circuit 211 is greater than a preset collector voltage value, the utility voltage detected by the utility voltage surge detection circuit 216 is greater than a preset surge value or the furnace temperature detected by the furnace temperature detection circuit 213 is greater than a preset furnace temperature value, the alarm device 217 makes an alarm sound.

In this embodiment, a power source end of the alarm device 217 is connected to the switching power supply circuit 206 (that is, a power supply voltage of the alarm device 217 is provided by the switching power supply circuit 206), and a control input end of the alarm device 217 is connected to the MCU 205.

In this embodiment, the alarm device in the alarm device 217 is a buzzer.

The working principle and the working flow of the electromagnetic heating control system of the system on chip of the embodiment are specifically described as follows:

the mains supply input from the mains supply input terminal 201 is rectified and filtered by the first rectifying and filtering circuit 202, and then is converted into smooth direct current to be provided to the resonant circuit 204; the commercial power input at the commercial power input end 201 is rectified and filtered by the second rectifying and filtering circuit 203, and then is converted into smooth direct current, which is provided to the switching power supply circuit 206 to provide power supply voltage for the operation of the electromagnetic heating control system of the system on chip in this embodiment;

(II) when the electromagnetic heating control system of the system-on-chip of this embodiment enters a heating state, firstly, the commercial power zero-crossing detection circuit 208 detects a zero-crossing point of the commercial power supply, and when the commercial power zero-crossing detection circuit 208 detects a zero-crossing of the commercial power supply, the MCU205 shields the detection output function of the IGBT voltage extreme value detection circuit 2051; then, the MCU205 controls the PWM generating circuit 2052 to output a PWM signal with a preset duty cycle and a preset frequency (for example, the duty cycle is 50%, and the frequency is 20 Khz) to the IGBT driving circuit 207 within a preset time period so as to control the switching of the IGBT transistor in the resonant circuit 204; then, when the preset time is up, the MCU205 enables the detection output function of the IGBT voltage extremum detecting circuit 2051; then, when the IGBT voltage extreme detection circuit 2051 detects that the collector voltage of the IGBT tube is the lowest point voltage, the MCU205 controls the PWM generation circuit 2052 to generate a conducting pulse width for conducting the IGBT tube in the resonant circuit 204. The above steps are repeated until the mains zero crossing detection circuit 208 next detects a zero crossing of the mains supply. In the electromagnetic heating control system of the system on chip of this embodiment, the IGBT is turned on when the collector voltage of the IGBT in the resonant circuit 204 is the lowest point voltage, so that the electromagnetic heating control system of the system on chip of this embodiment has an advantage of low power loss.

Thirdly, when the electromagnetic heating control system of the system on chip of this embodiment is in a heating process, the MCU205 controls the PWM generating circuit 2052 to output a corresponding PWM signal according to the mains voltage detected by the mains voltage detecting circuit 209 and the current flowing through the IGBT tube in the resonant circuit 204 detected by the IGBT current detecting circuit 210, so as to adjust the on-time and off-time of the IGBT tube in the resonant circuit 204, thereby adjusting the heating power of the electromagnetic heating control system of the system on chip of this embodiment;

fourthly, when the electromagnetic heating control system of the system on chip of the embodiment is in a heating process, the MCU205 outputs a corresponding control signal to the fan driving circuit 214 according to the temperature of the IGBT tube detected by the IGBT temperature detection circuit 212 and the furnace temperature detected by the furnace temperature detection circuit 213, so as to adjust the rotation speed of the fan in the electromagnetic heating device, thereby adjusting the temperature of the electromagnetic heating device;

(V) when the electromagnetic heating control system of the system-on-chip of this embodiment is in a heating process, the MCU205 controls the PWM generating circuit 2052 to output a corresponding PWM signal according to the power setting value input by the keypad communication interface circuit 215, so as to adjust the on-time and off-time of the IGBT in the resonance circuit 204, thereby adjusting the heating power of the electromagnetic heating control system of the system-on-chip of this embodiment;

(VI) when this embodiment system-on-chip's electromagnetic heating control system is in the heating process, mains voltage detection circuit 209 real-time detection mains voltage, IGBT current detection circuit 210 real-time detection in resonant circuit 204 the electric current of IGBT pipe, IGBT overvoltage detection circuit 211 real-time detection the collector electrode voltage of IGBT pipe, mains surge detection circuit 216 real-time detection mains surge, stove temperature detection circuit 213 real-time detection furnace temperature works as mains voltage that mains voltage detection circuit 209 detected is greater than preset mains voltage value, the electric current that IGBT current detection circuit 210 detected is greater than preset current value, that IGBT overvoltage detection circuit 211 detected the collector electrode voltage of IGBT pipe is greater than preset collector electrode voltage value, the surge that mains surge detection circuit 216 detected is greater than preset surge value or when stove temperature that stove temperature detection circuit 213 detected is greater than preset stove temperature value, MCU205 outputs corresponding control signal to alarm device 217's control input to control buzzer in the alarm device 217 sends the sound.

Referring to fig. 2 and 3 together, in the present embodiment, the resonant circuit 204 includes a resonant capacitor C21, a heating coil disk LH2, a resistor R21, a resistor RK2, a zener diode D21, and an IGBT tube Q2;

specifically, the first end OUT21 of the heating coil disk LH2 is connected to the output end a of the first rectifying-smoothing circuit 202 and the first end (corresponding to the end labeled with 1 in the figure) of the resonant capacitor C21, respectively, and the first end OUT22 of the heating coil disk LH2 is connected to the second end (corresponding to the end labeled with 2 in the figure) of the resonant capacitor C21 and the collector C of the IGBT tube Q2, respectively; the collector C of the IGBT tube Q2 is also connected with the detection input end of the IGBT voltage extreme value detection circuit 2051; the gate G of the IGBT Q2 is connected to the output end of the IGBT drive circuit (the gate G of the IGBT Q2 is the drive control input end of the resonant circuit 204), and the emitter E of the IGBT Q2 is grounded via the resistor RK 2; the cathode of the voltage-stabilizing diode D21 is connected with the gate G of the IGBT tube Q2, and the anode of the voltage-stabilizing diode D21 is connected with the emitter E of the IGBT tube Q2; the resistor R21 is connected in parallel with the zener diode D21.

In this embodiment, the IGBT driving circuit 207 includes a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a capacitor C22, a capacitor C23, and an IGBT driving chip 2071;

specifically, the resistor R22 and the resistor R23 are connected in parallel, one end of the resistor R22 and the resistor R23 connected in parallel is connected to the gate G of the IGBT Q2, and the other end of the resistor R22 and the resistor R23 connected in parallel is connected to the output end OUT of the IGBT driver chip 2071; the first power terminal VCC of the IGBT driver chip 2071 is connected to the first working voltage input terminal VCC1 through a resistor R24 (IN this embodiment, the first working voltage input terminal VCC1 is connected to the output terminal of the switching power supply circuit 206, the voltage of the first working voltage input terminal VCC1 is 5V), the first power terminal VCC of the IGBT driver chip 2071 is also grounded through a capacitor C23, the input terminal IN of the IGBT driver chip 2071 is connected to the first terminal of a resistor R25, and the second terminal of the resistor R25 (i.e., the terminal corresponding to the reference number PWM21, i.e., the input terminal of the IGBT driver circuit 207) is connected to the output terminal of the PWM generator circuit 2052; a second power supply end VDD of the IGBT driver chip 2071 is connected to the first end of the capacitor C22, the second end of the capacitor C22 is grounded, and the ground end of the IGBT driver chip 2071 is grounded; the first end of the capacitor C22 is further connected to a second operating voltage input terminal VCC2 (in this embodiment, the second operating voltage input terminal VCC2 is connected to the output terminal of the switching power supply circuit 206); the second operating voltage input terminal VCC2 is also connected to the output terminal of the PWM generation circuit 2052 via a resistor R26.

In this embodiment, the IGBT voltage limit detection circuit 2051 includes a voltage division circuit unit (composed of a resistor R27, a resistor R28, a resistor R29, a resistor R30, a capacitor C24, and a diode D22) and an active differentiation circuit unit 20511. The input end of the voltage dividing circuit unit is connected with the collector of the IGBT tube Q2, and the output end of the voltage dividing circuit unit is connected with the input end of the active differential circuit unit 20511; an output terminal of the active differential circuit unit 20511 is connected to an input terminal of the PWM generation circuit 2052.

Specifically, a first end of the resistor R27 (corresponding to a lower end of the resistor R27 in the figure, that is, a detection input end of the IGBT voltage extreme value detection circuit 2051) in the voltage division circuit unit is connected to the collector C of the IGBT transistor Q2, a second end of the resistor R27 is connected to a first end of the resistor R29 through a resistor R28, and a second end of the resistor R29 is grounded through a resistor R30; the second end of the resistor R29 is also connected with the anode of the diode D22; the cathode of the diode D22 is connected to the first operating voltage input terminal VCC 1; the capacitor C24 is connected with the resistor R30 in parallel;

the active differential circuit unit 20511 includes a first working voltage input terminal VCC1, a first resistor R31, a second resistor R32, a third resistor R33, a fourth resistor R34, a first capacitor C25, a second capacitor C26, and first voltage comparators a21-U4 inside the MCU 205.

Specifically, a first end of the first capacitor C25 (i.e., the input end of the active differential circuit unit 20511) is connected to a first end of the resistor R29 (i.e., the output end of the voltage divider circuit unit), and a second end of the first capacitor C25 is connected to a first end of a second resistor R32 via a first resistor R31; a second end of the second resistor R32 is connected to an output end of the first voltage comparator a 21-U4; the output terminals of the first voltage comparators a21-U4 are further connected to an input terminal of the PWM generation circuit 2052; the second capacitor C26 is connected in parallel with the second resistor R32; the first end of the second resistor R32 is further connected to the inverting input terminals of the first voltage comparators a21 to U4 (the voltages at the inverting input terminals of the first voltage comparators a21 to U4 are Vaa); the non-inverting input terminals of the first voltage comparators a21 to U4 are respectively connected to the first terminal of the third resistor R33 and the first terminal of the fourth resistor R34 (the non-inverting input terminals of the first voltage comparators a21 to U4 have a voltage Vbb); a second end of the third resistor R33 is connected to the first operating voltage input terminal VCC 1; the second end of the fourth resistor R34 is grounded.

In this embodiment, the PWM generating circuit 2052 includes a fifth resistor R35, a sixth resistor R36, second voltage comparators a21 to U1 inside the MCU205, and gates a21 to U2 inside the MCU205, and PWM generating modules a21 to U3 inside the MCU 205.

Specifically, the non-inverting input terminals of the second voltage comparators a21-U1 are connected to the output terminals of the first voltage comparators a21-U4 (i.e., the detection output terminal of the IGBT voltage extreme detection circuit 2051), and the inverting input terminals of the second voltage comparators a21-U1 are respectively connected to the first terminal of the fifth resistor R35 and the first terminal of the sixth resistor R36; a second end of the fifth resistor R35 is connected to the first operating voltage input terminal VCC 1; a second end of the sixth resistor R36 is grounded; the output end of the second voltage comparator A21-U1 is connected with the first input end IN1 of the AND gate A21-U2; the first input ends IN1 of the AND gates A21-U2 are connected with the output ends of the PWM generating modules A21-U3; the output ends of the AND gates A21-U2 are connected with the input ends of the PWM generating modules A21-U3; the output terminals of the PWM generation modules a21-U3 (i.e., the PWM pins of the MCU 205) are also connected to the second terminal of the resistor R25 in the IGBT driver circuit 207.

In this embodiment, the IGBT voltage extremum detecting circuit 2051 detects the voltage waveform of the collector C of the IGBT Q2 in the resonant circuit 204 in real time, the IGBT voltage extremum detecting circuit 2051 can capture the extreme points (including the highest point voltage and the lowest point voltage) of the voltage waveform of the collector C of the IGBT Q2 in real time, and when the IGBT voltage extremum detecting circuit 2051 detects that the collector voltage of the IGBT Q2 is the lowest point voltage, the PWM generating circuit 2052 outputs the conducting pulse width for conducting the IGBT Q2, so that the IGBT Q2 is in the conducting state.

The IGBT voltage extreme value detection circuit 2051 in this embodiment adopts the active differential circuit unit 20511 to realize the detection function of the voltage extreme value of the collector C of the IGBT Q2, and the active differential circuit has the advantage of wide response frequency band, and when the system frequency of this embodiment changes within the range of 20KHz to 30KHz, the IGBT voltage extreme value detection circuit 2051 can both accurately detect the voltage extreme value point of the collector C of the IGBT Q2, and the time deviation can be controlled at ns level, that is, the IGBT voltage extreme value detection circuit 2051 in this embodiment is realized by using the active differential circuit, and the stability and reliability of this embodiment can be improved (it should be noted that in other embodiments, the voltage extreme value of the collector of the IGBT Q2 can also be detected by using the passive differential circuit).

In this embodiment, the IGBT voltage extreme value detection circuit 2051 detects the collector voltage of the IGBT Q2, and when it is detected that the collector voltage of the IGBT Q2 is the lowest point voltage, the working principle and the working flow for controlling the turn-on of the IGBT Q2 are specifically described as follows:

in the electromagnetic heating control system of the system on chip of the embodiment, during the resonant heating process, when the IGBT tube Q2 is in the on state (in the embodiment, when the output terminals of the PWM generating modules a21-U3 output low level signals, the IGBT tube Q2 is on), current flows from the first end OUT21 of the heating coil disc LH2 to the second end OUT22 of the heating coil disc LH2 (i.e., current flows from the left end to the right end of the heating coil disc LH 2), the right end voltage of the resonant capacitor C21 (i.e., the end labeled as 2 in the figure, i.e., the collector voltage of the IGBT tube Q2) is pulled to the ground, and at this time, the right end voltage of the resonant capacitor C21 is about 0V. The collector voltage of the IGBT enters the input end of the active differential circuit unit 20511 through the left end of the first capacitor C25 after being divided by the resistor R27, the resistor R28, the resistor R29, and the resistor R30. In this embodiment, the first capacitor C25, the second resistor R32 and the second capacitor C26 in the active differentiating circuit unit 20511 are differential capacitors, feedback resistors and feedback capacitors, respectively. The third resistor R33 and the fourth resistor R34 form a voltage division circuit. In this embodiment, the second resistor R32 plays a role of amplifying the input differential signal, and the feedback capacitor C26 plays a role of stabilizing the output signal. According to the formula f =1/2 pi RC (in the present embodiment, f is an input resonance signal of 20Khz to 30 Khz), an appropriate differential capacitor C25 and first resistor R31 can be selected by formula calculation. Because the active differential circuit unit 20511 in this embodiment uses the single power supply method and performs offset processing on the comparison terminal voltages of the first voltage comparators a21 to U4, the output voltage Vout of the active differential circuit unit 20511 is calculated according to the output signal formula Vout = -R31C25 (dui/dt) + (V +) of the single power supply active differential circuit, where "V +" in the formula is a static voltage at the non-inverting input terminals of the first voltage comparators a21 to U4. Since the active differential circuit unit 20511 in this embodiment uses a single power supply method and biases the comparison terminal voltages of the first voltage comparators a21 to U4, vout is approximately equal to VCC1 × R34/(R33 + R34) V. In this embodiment, vout is input to the non-inverting input terminal of the second voltage comparator a21-U1, and the Vout signal input to the non-inverting input terminal of the second voltage comparator a21-U1 is compared with the reference voltage input to the inverting input terminal thereof (that is, the voltage Vref obtained by dividing the voltage of the first operating voltage input terminal VCC1 by the fifth resistor R35 and the sixth resistor R36, the voltage Vref = VCC1 × R36/(R35 + R36) V). In this embodiment, by configuring the appropriate third resistor R33, the fourth resistor R34, the fifth resistor R35, and the sixth resistor R36, VCC1 × R34/(R33 + R34) V is equal to VCC1 × R36/(R35 + R36) V, that is, the voltage at the non-inverting input terminal of the second voltage comparator a21-U1 is equal to the voltage at the inverting input terminal thereof in the static state. When the voltage of the non-inverting input terminal of the second voltage comparator a21-U1 is greater than the voltage of the inverting input terminal thereof (i.e., vout > VCC1 × R36/(R35 + R36) V), the output terminal of the second voltage comparator a21-U1 outputs a high level, otherwise outputs a low level;

(ii) the output terminals of the second voltage comparators a21-U1 are connected to the first input terminals IN1 of the and gates a21-U2, when the IGBT tube Q2 is IN a conducting state, the output terminals of the PWM generating modules a21-U3 IN this embodiment output a low level (i.e., when the output terminals of the PWM generating modules a21-U3 output a low level, that is, when the signal PWM21 IN the figure is a low level, the IGBT tube Q2 is turned on), and when the output terminals of the PWM generating modules a21-U3 output a low level, the output terminals of the and gates a21-U2 are also a low level, so that false trigger signals at the output terminals of the second voltage comparators a21-U1 can be shielded, so as to improve the stability and reliability of this embodiment;

and (iii) when the IGBT tube Q2 is in an off state (corresponding to when the output end of the PWM generation module a21-U3 outputs a high level), due to an inductance effect of the heating coil disc LH2, the current cannot suddenly change, and the current keeps flowing from the left end to the right end (i.e., the current continues to flow from the first end OUT21 of the heating coil disc LH2 to the second end OUT22 of the heating coil disc LH 2), and charges the resonant capacitor C21, so that the voltage at the right end of the resonant capacitor C21 (i.e., the voltage at the collector of the IGBT tube Q2) continuously increases in a sinusoidal relationship until the current of the heating coil disc LH2 is released. When the current of the heating coil disc LH2 is 0, the voltage of the right end of the resonance capacitor C21 reaches the highest value. The collector voltage of the IGBT Q2 is divided by a resistor R27, a resistor R28, a resistor R29, and a resistor R30, and then input to the input terminal of the active differential circuit unit 20511 through the left end of the differential capacitor C25. Because the active differential circuit unit 20511 in this embodiment uses the single power supply method and performs offset processing on the comparison terminal voltages of the first voltage comparators a21 to U4, the output voltage Vout of the active differential circuit unit 20511 is calculated according to the output signal formula Vout = -R31C25 (dui/dt) + (V +) of the single power supply active differential circuit, where "V +" in the formula is a static voltage at the non-inverting input terminals of the first voltage comparators a21 to U4. Where "V +" in the formula is the static voltage at the non-inverting input of the first voltage comparators A21-U4. It can be known that, before the collector voltage of the IGBT Q2 rises to the highest point voltage, (dui/dt) >0 in the formula Vout = -R31C25 (dui/dt) + (V +), so that Vout < V +, so that the output of the second voltage comparator a21-U1 inside the MCU205 outputs a low level, at this time, the output of the PWM generator module a21-U3 outputs a high level (i.e., the signal PWM21 in the figure is a high level), the output of the and gate a21-U2 outputs a low level, and when the collector voltage of the IGBT Q2 reaches the highest point voltage, i.e., (dui/dt) =0, so that Vout = V +.

And (iv) when the collector voltage of the IGBT tube Q2 reaches the highest voltage (i.e., when Vout = V +), the resonant capacitor C21 discharges to the heating coil disc LH2, and current flows from the right end of the heating coil disc LH2 (i.e., the second end OUT22 of the heating coil disc LH 2) to the left end of the heating coil disc LH2 (i.e., the first end OUT21 of the heating coil disc LH 2) until the discharging of the electric energy of the resonant capacitor C21 is completed (when the discharging of the electric energy of the resonant capacitor C21 is completed, the left end voltage of the resonant capacitor C21 is equal to the right end voltage thereof). Similarly, due to the inductance effect of the heating coil disc LH2, when the electric energy of the resonant capacitor C21 is released, the current still flows on the heating coil disc LH2 from the right end to the left end, and at this time, the voltage at the left end of the resonant capacitor C21 is clamped to the mains voltage, and the voltage at the right end of the resonant capacitor C21 is pulled down continuously until the current flowing on the heating coil disc LH2 from the right end to the left end drops to 0. In the above process, the collector voltage of the IGBT Q2 decreases in a sinusoidal relationship. Because the active differential circuit unit 20511 in this embodiment uses the single power supply mode and performs the bias processing on the comparison terminal voltage of the first voltage comparators a21-U4, the output voltage Vout of the active differential circuit unit 20511 is calculated according to the output signal formula Vout = -R31C25 (dui/dt) + (V +) of the single power supply active differential circuit, where "V +" in the formula is the static voltage of the non-inverting input terminals of the first voltage comparators a21-U4, and V + is approximately equal to VCC 1R 34/(R33 + R34) V, so that Vout > V +, vout becomes greater than V + when the collector voltage of the IGBT Q2 drops from the peak voltage (i.e., the highest point voltage), therefore, the output end signals of the second voltage comparators a21-U1 inside the MCU205 jump from a low level to a high level, at this time, both the two input ends of the and gates a21-U2 (i.e., the PWM pins of the MCU205 and the output ends of the second voltage comparators a21-U1 inside the MCU 205) are at a high level, and further, the output end signals of the and gates a21-U2 also jump from a low level to a high level, i.e., an edge trigger is generated at the output ends of the and gates a21-U2, at this time, the MCU205 can read the collector voltage of the IGBT tube Q2, and at this time, the voltage read by the MCU205 is the peak voltage (i.e., the peak voltage of the collector voltage of the IGBT tube Q2). In addition, in this embodiment, when it is detected that the peak voltage of the collector voltage of the IGBT Q2 is greater than a preset collector voltage value (for example, greater than 1200V), in a next on-period of the IGBT Q2, the on-time of the IGBT Q2 is reduced, so as to reduce a reverse peak voltage of the collector voltage of the IGBT Q2 in the next on-period, and make the IGBT Q2 operate more reliably;

(V) when the collector voltage of the IGBT Q2 continuously decreases and gradually becomes 0V, because the active differentiation circuit unit 20511 in this embodiment uses a single power supply mode and biases the comparison terminal voltage of the first voltage comparators a21 to U4, the output voltage Vout of the active differentiation circuit unit 20511 is calculated according to the output signal formula Vout = -R31C25 (dui/dt) + (V +) of the single power supply active differentiation circuit, where "V +" in the formula is a static voltage of the non-inverting input terminals of the first voltage comparators a21 to U4, V + is approximately equal to VCC1 = -R34/(R33 + R34) V, vout = V +, the output terminal of the voltage comparators a11 to U1 inside the MCU205 outputs a low level, so that the output signals of the and gates a21 to U2 jump from high level to low level, and when the output signals of the and gates a21 to U2 jump from high level to low level, the IGBT Q2 is turned on, and the PWM module Q21 to generate a PWM Q2. And (5) repeating the processes from (one) to (five) in the next resonance period.

In summary, in the electromagnetic heating control system of the system on chip provided in this embodiment, when the IGBT voltage extreme value detection circuit 2051 detects that the collector voltage of the IGBT Q2 in the resonant circuit 204 is the lowest point voltage, the PWM generation modules a21 to U3 inside the MCU205 are triggered to generate a PWM on pulse width for turning on the IGBT Q2, so that the electromagnetic heating control system of the system on chip of this embodiment can greatly reduce the power loss of the circuit compared with the electromagnetic heating control system in the prior art shown in fig. 1; in addition, the electromagnetic heating control system of the system on chip of the embodiment also has the advantage of high reliability.

The electromagnetic heating control system of the system on chip provided by this embodiment is used for controlling the resonant heating operation of an electromagnetic heating device, and includes a mains supply input end, a first rectifying and filtering circuit, a second rectifying and filtering circuit, a resonant circuit, an IGBT drive circuit, an MCU and a switching power supply circuit; the resonance circuit comprises an IGBT tube; an IGBT voltage extreme value detection circuit and a PWM generation circuit are arranged in the MCU; the first rectifying and filtering circuit is used for rectifying and filtering a mains supply and supplying power to the resonant circuit; the second rectification filter circuit is used for rectifying and filtering the mains supply and supplying power to the switching power supply circuit; the resonant circuit is used for carrying out resonant heating on the electromagnetic heating device; the IGBT tube is used for controlling the heating state of the resonance circuit; the switching power supply circuit is used for supplying power to the MCU and the IGBT driving circuit; the IGBT driving circuit is used for driving the resonant circuit to work; the MCU is used for controlling the heating work of the resonance circuit; the IGBT voltage extreme value detection circuit is used for detecting the voltage extreme value of the collector of the IGBT tube; and the PWM generating circuit is used for outputting a corresponding PWM signal to the IGBT driving circuit according to the detection result of the IGBT voltage extreme value detection circuit so as to control the switching action of the IGBT tube. The electromagnetic heating control system of the system on chip provided by the embodiment has the advantages of low power loss and high reliability; meanwhile, the electromagnetic heating control system of the system on chip of the embodiment also has the advantages of simple circuit structure and easy realization.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An electromagnetic heating control system of a system-on-chip is used for controlling the resonant heating work of an electromagnetic heating device, and is characterized by comprising a mains supply input end (201), a first rectifying and filtering circuit (202), a second rectifying and filtering circuit (203), a resonant circuit (204), an MCU (205), a switching power supply circuit (206) and an IGBT driving circuit (207); the resonant circuit (204) comprises an IGBT tube; an IGBT voltage extreme value detection circuit (2051) and a PWM generation circuit (2052) are arranged in the MCU (205); wherein,

the first rectifying and filtering circuit (202) is used for rectifying and filtering the mains supply input by the mains supply input end (201) and supplying power to the resonant circuit (204);

the second rectifying and filtering circuit (203) is used for rectifying and filtering the mains supply input by the mains supply input end (201) and supplying power to the switching power supply circuit (206);

the resonance circuit (204) is used for performing resonance heating on the electromagnetic heating device; the IGBT tube is used for controlling the heating state of the resonance circuit (204);

the switching power supply circuit (206) is used for supplying power to the MCU (205) and the IGBT drive circuit (207);

the IGBT driving circuit (207) is used for driving the resonant circuit (204) to work;

the MCU (205) is used for controlling the heating work of the resonant circuit (204); the IGBT voltage extreme value detection circuit (2051) is used for detecting the voltage extreme value of the collector of the IGBT tube; the PWM generating circuit (2052) is used for outputting a corresponding PWM signal to the IGBT driving circuit (207) according to the detection result of the IGBT voltage extreme value detection circuit (2051) so as to control the switching action of the IGBT tube;

the input end of the first rectifying and filtering circuit (202) and the input end of the second rectifying and filtering circuit (203) are both connected with the mains supply input end (201), the output end of the first rectifying and filtering circuit (202) is connected with the power supply input end of the resonance circuit (204), and the output end of the second rectifying and filtering circuit (203) is connected with the input end of the switching power supply circuit (206); the output end of the switching power supply circuit (206) is respectively connected with the power supply end of the MCU (205) and the power supply end of the IGBT driving circuit (207); the input end of the IGBT driving circuit (207) is connected with the output end of the PWM generating circuit (2052), and the output end of the IGBT driving circuit (207) is connected with the driving control input end of the resonance circuit (204); the detection input end of the IGBT voltage extreme value detection circuit (2051) is connected with the collector electrode of the IGBT tube, and the detection output end of the IGBT voltage extreme value detection circuit (2051) is connected with the input end of the PWM generation circuit (2052).

2. The system-on-chip electromagnetic heating control system of claim 1, further comprising a mains zero-crossing detection circuit (208) for detecting zero-crossing points of the mains supply; the detection input end of the commercial power zero-crossing detection circuit (208) is connected with the output end of the second rectifying and filtering circuit (203), the detection output end of the commercial power zero-crossing detection circuit (208) is connected with the first signal input end of the MCU (205), and the MCU (205) shields the detection output function of the IGBT voltage extreme value detection circuit (2051) and controls the PWM generation circuit (2052) to output PWM signals with preset duty ratio and preset frequency to the IGBT driving circuit (207) in a preset time period so as to control the switching action of the IGBT tube when the commercial power zero-crossing detection circuit (208) detects the zero crossing of the commercial power supply.

3. The system for controlling electromagnetic heating of a system on a chip as set forth in claim 2, wherein a detection input terminal of the IGBT voltage extreme value detection circuit (2051) is connected to the collector of the IGBT transistor in the resonant circuit (204), a detection output terminal of the IGBT voltage extreme value detection circuit (2051) is connected to an input terminal of the PWM generation circuit (2052), and the IGBT voltage extreme value detection circuit (2051) controls the PWM generation circuit (2052) to output a conducting pulse width for conducting the IGBT transistor when detecting that the voltage at the collector of the IGBT transistor is the lowest point voltage.

4. The system-on-chip electromagnetic heating control system according to claim 3, wherein the IGBT voltage extremity detection circuit (2051) comprises a voltage divider circuit unit (R27, R28, R29, R30, C24, D22) and an active differential circuit unit (20511); wherein,

the input end of the voltage division circuit unit is connected with the collector electrode of the IGBT tube, and the output end of the voltage division circuit unit is connected with the input end of the active differential circuit unit (20511); an output terminal of the active differential circuit unit (20511) is connected to an input terminal of the PWM generation circuit (2052).

5. The system-on-chip electromagnetic heating control system of claim 4, wherein the active differential circuit unit (20511) comprises a first operating voltage input terminal (VCC 1), a first resistor (R31), a second resistor (R32), a third resistor (R33), a fourth resistor (R34), a first capacitor (C25), a second capacitor (C26), and a first voltage comparator (A21-U4) inside the MCU (205); wherein,

a first end of the first capacitor (C25) is connected with an output end of the voltage division circuit unit, and a second end of the first capacitor (C25) is connected with a first end of the second resistor (R32) through the first resistor (R31); a second end of the second resistor (R32) is connected with an output end of the first voltage comparator (A21-U4); the output end of the first voltage comparator (A21-U4) is also connected with the input end of the PWM generating circuit; the second capacitor (C26) is connected in parallel with the second resistor (R32); the first end of the second resistor (R32) is also connected with the inverted input end of the first voltage comparator (A21-U4); the non-inverting input ends of the first voltage comparators (A21-U4) are respectively connected with the first end of the third resistor (R33) and the first end of the fourth resistor (R34); a second end of the third resistor (R33) is connected with the first working voltage input end (VCC 1); the second end of the fourth resistor (R34) is grounded.

6. The system-on-chip electromagnetic heating control system of claim 5, wherein the PWM generation circuit (2052) comprises a fifth resistor (R35), a sixth resistor (R36), a second voltage comparator (A21-U1) internal to the MCU (205), an AND gate (A21-U2) internal to the MCU (205), and a PWM generation module (A21-U3) internal to the MCU (205); wherein,

the non-inverting input end of the second voltage comparator (A21-U1) is connected with the output end of the first voltage comparator (A21-U4), and the inverting input end of the second voltage comparator (A21-U1) is respectively connected with the first end of the fifth resistor (R35) and the first end of the sixth resistor (R36); a second end of the fifth resistor (R35) is connected with the first working voltage input end (VCC 1); a second end of the sixth resistor (R36) is grounded; the output end of the second voltage comparator (A21-U1) is connected with the first input end (IN 1) of the AND gate (A21-U2); the first input end (IN 1) of the AND gate (A21-U2) is connected with the output end of the PWM generating module (A21-U3); the output end of the AND gate (A21-U2) is connected with the input end of the PWM generating module (A21-U3); the output end of the PWM generation module (A21-U3) is also connected with the input end of the IGBT driving circuit (207).

7. The system-on-chip electromagnetic heating control system according to claim 6, further comprising a mains voltage detection circuit (209) for detecting a voltage of the mains power supply, an IGBT current detection circuit (210) for detecting a current of the IGBT tube, and an IGBT overvoltage detection circuit (211) for detecting whether a collector voltage of the IGBT tube is overvoltage or not; the detection input end of the mains voltage detection circuit (209) is connected with the output end of the second rectification filter circuit (203), and the detection output end of the mains voltage detection circuit (209) is connected with the second signal input end of the MCU (205); the detection input end of the IGBT current detection circuit (210) is connected with the current output end of the IGBT tube, and the detection output end of the IGBT current detection circuit (210) is connected with the third signal input end of the MCU (205); the detection input end of the IGBT overvoltage detection circuit (211) is connected with the collector electrode of the IGBT tube, and the detection output end of the IGBT overvoltage detection circuit (211) is connected with the fourth signal input end of the MCU (205).

8. The system-on-chip electromagnetic heating control system of claim 7, further comprising a keypad communication interface circuit (215) for inputting a power setting value of the electromagnetic heating device and a mains surge detection circuit (216) for detecting a surge of the mains power supply; the power end of the keypad communication interface circuit (215) is connected with the switching power circuit (206), and the output end of the keypad communication interface circuit (215) is connected with the fifth signal input end of the MCU (205); the detection input end of the mains surge detection circuit (216) is connected with the output end of the second rectifying and filtering circuit (203), and the detection output end of the mains surge detection circuit (216) is connected with the sixth signal input end of the MCU (205).

9. The system-on-chip electromagnetic heating control system according to claim 8, further comprising an alarm device (217) for sounding an alarm when the mains voltage detected by the mains voltage detection circuit (209) is greater than a preset mains voltage value, the current detected by the IGBT current detection circuit (210) is greater than a preset current value, the collector voltage of the IGBT detected by the IGBT overvoltage detection circuit (211) is greater than a preset collector voltage value, or the mains surge detected by the mains surge detection circuit (216) is greater than a preset surge value; the power end of the alarm device (217) is connected with the switching power supply circuit (206), and the control input end of the alarm device (217) is connected with the MCU (205).