CN110972344A

CN110972344A - Electromagnetic heating circuit, electromagnetic heating appliance and protection method of electromagnetic heating circuit

Info

Publication number: CN110972344A
Application number: CN201910872460.6A
Authority: CN
Inventors: 刘学宇; 赵礼荣
Original assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Current assignee: Zhejiang Shaoxing Supor Domestic Electrical Appliance Co Ltd
Priority date: 2019-09-16
Filing date: 2019-09-16
Publication date: 2020-04-07
Anticipated expiration: 2039-09-16
Also published as: CN110972344B

Abstract

The invention provides an electromagnetic heating circuit (100), an electromagnetic heating appliance (10) and a method for protecting the electromagnetic heating circuit (100). An electromagnetic heating circuit (100) comprises: rectifier circuit (101) that connect gradually, filter circuit (102), resonant circuit (103), insulated gate bipolar transistor IGBT module (104), drive circuit (105) and control circuit (106), the first input of control circuit (106) is connected with resonant circuit's (103) input electricity, the second input of control circuit (106) is connected with resonant circuit's (103) output electricity, thereby the relation between the voltage on two input through control circuit (106), need not to turn off surge protection function when making to examine the pot, and the relation of the output width of pot signal and predetermineeing the width is examined in comparison, avoided damaging IGBT module (104) because surge interference.

Description

Electromagnetic heating circuit, electromagnetic heating appliance and protection method of electromagnetic heating circuit

Technical Field

The invention relates to the technical field of induction cookers, in particular to an electromagnetic heating circuit, an electromagnetic heating appliance and an electromagnetic heating circuit protection method.

Background

The electromagnetic heating circuit can convert electric energy into heat energy by utilizing the electromagnetic induction principle to heat equipment to be heated (such as a cooker). The electromagnetic heating circuit has wide application field, and can be applied to various electromagnetic heating appliances needing heating function, such as an electromagnetic oven, an electric rice cooker, an electric pressure cooker, a soybean milk machine, a coffee machine, a stirrer and the like.

At present, when an induction cooker heating circuit is started each time, a control circuit in the induction cooker heating circuit outputs a signal of about 8 microseconds to turn on an Insulated Gate Bipolar Transistor (IGBT) module, so as to detect whether a device to be heated is on an electromagnetic heating appliance adopting the induction cooker heating circuit.

Generally, the control circuit in the electromagnetic heating circuit calculates the pot detection time length of about 8 microseconds by using the command cycle delay. However, in order to accurately calculate the pot detection time length, the control circuit needs to turn off an interruption system which is generally used for surge protection of the electromagnetic heating circuit. Therefore, once surge interference occurs in a power supply grid at the moment, the electromagnetic heating circuit cannot be subjected to surge protection due to the fact that the interruption system is closed, the IGBT module is easily damaged, the electromagnetic heating circuit cannot normally work, and the device cost of the electromagnetic heating appliance is increased.

Disclosure of Invention

The invention provides an electromagnetic heating circuit, an electromagnetic heating appliance and an electromagnetic heating circuit protection method, which are used for simultaneously realizing the pot detection process and the surge protection process of the electromagnetic heating circuit, avoiding the phenomenon that an IGBT module is damaged due to surge interference, reducing the device cost of the electromagnetic heating circuit and improving the reliability of the electromagnetic heating circuit.

In a first aspect, the present invention provides an electromagnetic heating circuit comprising: the device comprises a rectifying circuit, a filter circuit, a resonant circuit, an insulated gate bipolar transistor IGBT module, a drive circuit and a control circuit;

the power supply circuit comprises a rectifier circuit, a filter circuit, a control circuit, a resonant circuit, a drain electrode of an IGBT module, a source electrode of the IGBT module, a negative output end of the rectifier circuit, a grid electrode of the IGBT module, a positive output end of the filter circuit, a negative output end of the rectifier circuit, a negative output end of the filter circuit and a source electrode of the IGBT module, wherein the rectifier circuit is used for rectifying input power supply voltage, the positive output end of the rectifier circuit is electrically connected with a first input end of the filter circuit, the output end of the filter circuit and the first input end of the control circuit are respectively electrically connected with an input end of the resonant circuit, the drain electrode of the IGBT module and a second input end of the control circuit are respectively electrically connected;

the control circuit is used for controlling the voltage on the first input end of the control circuit to be smaller than the voltage on the second input end of the control circuit when a trigger instruction is received, and the trigger instruction is used for indicating the control circuit to start pot detection;

the control circuit is further configured to control the voltage at the first input terminal of the control circuit to be greater than or equal to the voltage at the second input terminal of the control circuit when the voltage at the first input terminal of the control circuit is less than the voltage at the second input terminal of the control circuit; when the voltage on the first input end of the control circuit is greater than or equal to the voltage on the second input end of the control circuit, sending a pot detection signal to the driving circuit, wherein the pot detection signal is used for detecting whether equipment to be heated is arranged on the electromagnetic heating appliance or not; when the output width of the pot detection signal is greater than or equal to a preset width, sending a pot detection stopping signal to the driving circuit, wherein the pot detection stopping signal is used for stopping detecting whether the electromagnetic heating device is provided with the equipment to be heated, and the pot detection stopping signal have opposite levels;

the drive circuit is used for driving the IGBT module to be conducted according to the pot detection signal; and driving the IGBT module to be disconnected according to the pot detection stopping signal.

Optionally, the control circuit comprises: the device comprises a synchronous comparator circuit, a pulse program generator PPG output control circuit, a voltage division circuit and a micro control unit MCU;

the control end of the MCU is electrically connected with the target end of the synchronous comparator circuit, the target end of the synchronous comparator circuit is a same-direction input end or a reverse-direction input end of the synchronous comparator circuit, the first input end of the voltage division circuit is electrically connected with the input end of the resonance circuit, the second input end of the voltage division circuit is electrically connected with the output end of the resonance circuit, the first output end of the voltage division circuit is electrically connected with the same-direction input end of the synchronous comparator circuit, the second output end of the voltage division circuit is electrically connected with the reverse-direction input end of the synchronous comparator circuit, the output end of the synchronous comparator circuit is electrically connected with the input end of the PPG output control circuit, and the output end of the PPG output control circuit is electrically connected with the input end of the driving circuit;

the MCU is used for controlling the target end of the synchronous comparator circuit to be in an output state and changing the voltage on the target end of the synchronous comparator circuit when the trigger instruction is received, so that the voltage on the same-direction input end of the synchronous comparator circuit is smaller than the voltage on the reverse-direction input end of the synchronous comparator circuit; when the voltage on the equidirectional input end of the synchronous comparator circuit is smaller than the voltage on the reverse input end of the synchronous comparator circuit, controlling the target end of the synchronous comparator circuit to be in an input state, and stopping changing the voltage on the target end of the synchronous comparator circuit so as to enable the voltage on the equidirectional input end of the synchronous comparator circuit to be larger than or equal to the voltage on the reverse input end of the synchronous comparator circuit;

the synchronous comparator circuit is used for outputting a first signal to the PPG control output voltage when the voltage on the equidirectional input end of the synchronous comparator circuit is smaller than the voltage on the reverse input end of the synchronous comparator circuit; when the voltage on the same-direction input end of the synchronous comparator circuit is greater than or equal to the voltage on the reverse-direction input end of the synchronous comparator circuit, outputting a trigger signal with the level opposite to that of the first signal to the PPG control output circuit;

the PPG output control circuit is used for sending the pot detection signal to the drive circuit according to the trigger signal; and when the output width of the pot detection signal is greater than or equal to the preset width, outputting the pot detection stopping signal to the driving circuit.

Optionally, the MCU is configured to control the equidirectional input end of the synchronous comparator circuit to be in an output state and pull down the voltage at the equidirectional input end of the synchronous comparator circuit when the target end of the control circuit is the equidirectional input end of the synchronous comparator circuit, so that the voltage at the equidirectional input end of the synchronous comparator circuit is smaller than the voltage at the reverse input end of the synchronous comparator circuit; when the voltage on the equidirectional input end of the synchronous comparator circuit is smaller than the voltage on the reverse input end of the synchronous comparator circuit, the equidirectional input end of the synchronous comparator circuit is controlled to be in an input state, and the voltage on the equidirectional input end of the synchronous comparator circuit stops being pulled down, so that the voltage on the equidirectional input end of the synchronous comparator circuit is larger than or equal to the voltage on the reverse input end of the synchronous comparator circuit.

Optionally, the MCU is configured to control the inverting input terminal of the synchronous comparator circuit to be in an output state when the target terminal of the control circuit is the inverting input terminal of the synchronous comparator circuit, and to set a voltage at the inverting input terminal of the synchronous comparator circuit high, so that the voltage at the non-inverting input terminal of the synchronous comparator circuit is lower than the voltage at the inverting input terminal of the synchronous comparator circuit; when the voltage on the equidirectional input end of the synchronous comparator circuit is smaller than the voltage on the reverse input end of the synchronous comparator circuit, the reverse input end of the synchronous comparator circuit is controlled to be in an input state, and the voltage on the reverse input end of the synchronous comparator circuit is stopped to be set high, so that the voltage on the equidirectional input end of the synchronous comparator circuit is larger than or equal to the voltage on the reverse input end of the synchronous comparator circuit.

Optionally, an input end of the MCU is electrically connected to an output end of the synchronous comparator circuit, and is configured to obtain the number of turns of the synchronous comparator circuit, where the number of turns is used to determine whether there is a device to be heated on the electromagnetic heating apparatus.

Optionally, the driving circuit comprises: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first triode, a second triode, a third triode and a first capacitor;

wherein, the first end of the first resistor, the first end of the third resistor and the drain of the second triode are connected with a preset level, the output end of the control circuit is electrically connected between the second end of the first resistor and the first end of the second resistor, the second end of the first resistor is electrically connected with the first end of the second resistor, the second end of the second resistor is electrically connected with the grid of the first triode, the second end of the third resistor is electrically connected with the drain of the first triode and the grid of the second triode respectively, the first end of the first capacitor is electrically connected between the drain of the first triode and the grid of the third triode, the second end of the first capacitor, the source of the first triode and the drain of the third triode are all grounded, and the source of the second triode is electrically connected with the first end of the fourth resistor, the second end of the fourth resistor is electrically connected with the source electrode of the third triode, and the grid electrode of the IGBT module is electrically connected between the second end of the fourth resistor and the source electrode of the third triode.

Optionally, the electromagnetic heating circuit further comprises: a protection circuit; the protection circuit includes: a fifth resistor, a sixth resistor and a voltage stabilizing diode;

the output end of the driving circuit is respectively and electrically connected with the first end of the voltage stabilizing diode and the first end of the fifth resistor, the second end of the fifth resistor is respectively and electrically connected with the first end of the sixth resistor and the grid electrode of the IGBT module, and the second end of the voltage stabilizing diode, the second end of the sixth resistor and the source electrode of the IGBT module are all grounded.

Optionally, the resonant circuit comprises: a second capacitor and a resonant inductor;

the output end of the filter circuit and the first input end of the control circuit are respectively and electrically connected with the first end of the resonance inductor, the drain electrode of the IGBT module and the second input end of the control circuit are respectively and electrically connected with the second end of the resonance inductor, and the second capacitor is connected with the resonance inductor in parallel.

Optionally, the voltage divider circuit includes: a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor;

the first end of the seventh resistor is electrically connected with the input end of the resonant circuit, the first end of the eighth resistor is electrically connected with the output end of the resonant circuit, the second end of the seventh resistor is electrically connected with the first end of the ninth resistor, the second end of the eighth resistor is electrically connected with the first end of the tenth resistor, the second end of the ninth resistor and the second end of the tenth resistor are both grounded, the first input end of the control circuit is electrically connected between the second end of the seventh resistor and the first end of the ninth resistor, and the second input end of the control circuit is electrically connected between the second end of the eighth resistor and the first end of the tenth resistor.

Optionally, the filter circuit comprises: a third capacitor;

the first end of the third capacitor is electrically connected between the positive output end of the rectifying circuit and the input end of the resonant circuit, and the second end of the third capacitor is grounded.

Optionally, the electromagnetic heating circuit further comprises: a surge detection circuit;

the first input end of the surge detection circuit is electrically connected with the first input end of the rectifying circuit, the second input end of the surge detection circuit is electrically connected with the second input end of the rectifying circuit, and the output end of the surge detection circuit is electrically connected with the third input end of the control circuit;

the surge detection circuit is used for sending a surge signal to the control circuit when the surge interference in the power supply voltage is detected;

and the control circuit is also used for sending the pot detection stopping signal to the drive circuit when receiving the surge signal.

Optionally, the surge detection circuit includes: the first diode, the second diode, the eleventh resistor and the twelfth resistor;

the positive electrode of the first diode is electrically connected with the first input end of the rectifying circuit, the positive electrode of the second diode is electrically connected with the second input end of the rectifying circuit, the negative electrode of the first diode and the negative electrode of the second diode are respectively electrically connected with the first end of the eleventh resistor, the second end of the eleventh resistor is electrically connected with the first end of the twelfth resistor, the second end of the twelfth resistor is grounded, and the third input end of the control circuit is electrically connected between the second end of the eleventh resistor and the first end of the twelfth resistor.

In a second aspect, the present invention provides an electromagnetic heating appliance comprising: the electromagnetic heating circuit of the first aspect.

In a third aspect, the present invention provides a protection method for an electromagnetic heating circuit, which is applied to the electromagnetic heating circuit according to the first aspect.

The method comprises the following steps:

when a trigger instruction is received, controlling the voltage on the first input end of the control circuit to be smaller than the voltage on the second input end of the control circuit;

when the voltage on the first input end of the control circuit is smaller than the voltage on the second input end of the control circuit, controlling the voltage on the first input end of the control circuit to be larger than or equal to the voltage on the second input end of the control circuit;

when the voltage on the first input end of the control circuit is controlled to be larger than or equal to the voltage on the second input end of the control circuit, a pot detection signal is sent to the drive circuit, so that the drive circuit drives the IGBT module to be conducted according to the pot detection signal, and the pot detection signal is used for detecting whether equipment to be heated is arranged on the electromagnetic heating appliance or not;

when the pot detection signal is sent to the driving circuit, timing is started to be carried out on the output width of the pot detection signal, when the output width of the pot detection signal is larger than or equal to the preset width, the pot detection stopping signal is sent to the driving circuit, so that the driving circuit drives the IGBT module to be disconnected according to the pot detection stopping signal, the pot detection stopping signal is used for stopping detecting whether the electromagnetic heater is provided with the equipment to be heated, and the levels of the pot detection signal and the pot detection stopping signal are opposite.

Optionally, the target terminal of the control circuit is a first input terminal of the control circuit or a second input terminal of the control circuit;

controlling the voltage on the first input of the control circuit to be less than the voltage on the second input of the control circuit, comprising:

controlling a target end of the control circuit to be in an output state;

modifying a voltage on a target terminal of the control circuit such that a voltage on a first input terminal of the control circuit is less than a voltage on a second input terminal of the control circuit;

controlling a voltage at a first input of the control circuit to be greater than or equal to a voltage at a second input of the control circuit, comprising:

controlling a target end of the control circuit to be in an input state;

and stopping changing the voltage on the target end of the control circuit, so that the voltage on the first input end of the control circuit is greater than or equal to the voltage on the second input end of the control circuit.

Optionally, when the target terminal of the control circuit is the first input terminal of the control circuit,

the altering a voltage on a target terminal of the control circuit comprises:

pulling down a voltage on a target terminal of the control circuit;

the ceasing to alter the voltage on the target terminal of the control circuit comprises:

stopping pulling down the voltage on the target terminal of the control circuit.

Optionally, when the target terminal of the control circuit is the second input terminal of the control circuit,

the altering a voltage on a target terminal of the control circuit comprises:

raising a voltage on a target terminal of the control circuit;

stopping raising the voltage on the target terminal of the control circuit.

Optionally, the method further comprises;

receiving a surge signal sent by a surge detection circuit, wherein the surge signal is used for indicating that surge interference exists in the power supply voltage;

and sending the pot detection stopping signal to the driving circuit.

According to the electromagnetic heating circuit, the electromagnetic heating appliance and the protection method of the electromagnetic heating circuit, provided by the invention, the control circuit can start to detect the pot when a trigger instruction is received. When the pot is detected, the control circuit can change the state of the first input end or the state of the second input end of the control circuit into an output state. The control circuit can control the voltage on the first input end of the control circuit to be smaller than the voltage on the second input end of the control circuit by changing the voltage on the first input end or the second input end of the control circuit. The control circuit may then change the state of the first input terminal or the state of the second input terminal of the control circuit to the input state. The control circuit may stop controlling the voltage at the first input terminal of the control circuit to be less than the voltage at the second input terminal of the control circuit by stopping changing the voltage at the first input terminal or the second input terminal of the control circuit. The first input end based on the control circuit is electrically connected with the input end of the resonance circuit, so that the voltage on the first input end of the control circuit can change along with the change of the voltage on the input end of the resonance circuit, and the second input end based on the control circuit is electrically connected with the output end of the resonance circuit, so that the voltage on the second input end of the control circuit can change along with the change of the voltage on the output end of the resonance circuit. In the normal operation process of the electromagnetic heating circuit, the voltage at the input end of the resonant circuit is greater than the voltage at the output end of the resonant circuit, so that the voltage at the first input end of the control circuit is gradually changed from being smaller than the voltage at the second input end of the control circuit to being greater than or equal to the voltage at the second input end of the control circuit. Therefore, when the voltage on the first input end of the control circuit is larger than or equal to the voltage on the second input end of the control circuit, the control circuit can continuously send a pot detection signal to the drive circuit, so that the drive circuit can continuously drive the IGBT module to be conducted according to the pot detection signal. When the output width of the pot detection signal is larger than or equal to the preset width, the control circuit can stop sending the pot detection signal to the driving circuit and send the pot detection stopping signal to the driving circuit, so that the driving circuit can drive the IGBT module to be disconnected according to the pot detection stopping signal. And then, by collecting various parameters of the electromagnetic heating circuit in the process, determining whether the electromagnetic heating appliance comprising the electromagnetic heating circuit is provided with equipment to be heated or not so as to finish the pot detection process of the electromagnetic heating circuit. In the embodiment, the control circuit is triggered through the resonant circuit, a relay system for providing surge protection is not required to be turned off when the pot is detected, the pot detection process and the surge protection process of the electromagnetic heating circuit are realized simultaneously, the phenomenon that an IGBT module is damaged due to surge interference is avoided, the device cost of the electromagnetic heating circuit is reduced, and the reliability of the electromagnetic heating circuit is improved. In addition, the width of the pot detection signal can be flexibly and freely set, and the software program of the electromagnetic heating circuit is simplified.

Drawings

In order to more clearly illustrate the technical solutions of the present invention or the prior art, the following briefly introduces the drawings needed to be used in the description of the embodiments or the prior art, and obviously, the drawings in the following description are some embodiments of the present invention, and those skilled in the art can obtain other drawings according to the drawings without inventive labor.

Fig. 1 is a schematic structural diagram of an electromagnetic heating circuit provided in the present invention;

fig. 2 is a schematic circuit structure diagram of an electromagnetic heating circuit provided in the present invention;

FIG. 3a is a schematic graph illustrating the voltage at the non-inverting input of the synchronous comparator circuit and the voltage at the inverting input of the synchronous comparator circuit in the electromagnetic heating circuit provided by the present invention;

FIG. 3b is a schematic graph of the voltage at the non-inverting input of the synchronous comparator circuit and the voltage at the inverting input of the synchronous comparator circuit in the electromagnetic heating circuit provided by the present invention;

FIG. 4 is a graph illustrating pot detection signals and voltages at the drain of an IGBT module in the electromagnetic heating circuit provided by the present invention;

FIG. 5 is a schematic structural diagram of an electromagnetic heating circuit provided in the present invention;

fig. 6 is a schematic circuit structure diagram of an electromagnetic heating circuit provided in the present invention;

FIG. 7 is a schematic structural diagram of an electromagnetic heating device provided by the present invention;

fig. 8 is a schematic flow chart of a protection method for an electromagnetic heating circuit according to the present invention.

Description of reference numerals:

100-an electromagnetic heating circuit; 101-a rectifying circuit;

102-a filter circuit; 103-a resonant circuit;

104-IGBT module; 105-a drive circuit;

106-a control circuit; 107-protection circuit;

108-surge detection circuit; 1061 — synchronous comparator circuit;

1062-PPG output control circuit; 1063-voltage divider circuit;

1064-MCU; 10-electromagnetic heating appliance.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the conventional electromagnetic heating circuit, the control circuit outputs a signal of about 8 microseconds every time the electromagnetic heating circuit is started, so as to detect whether the equipment to be heated on the electromagnetic heating appliance is detected and whether the equipment to be heated is appropriate. The pot detection time length of 8 microseconds is usually calculated by a control circuit by using instruction cycle time delay in a software program. In order to accurately calculate the pot detection time length, the control circuit needs to turn off an interruption system, and the interruption system is generally used for surge protection of the electromagnetic heating circuit. Therefore, once surge interference occurs in a power supply grid, the electromagnetic heating circuit cannot be protected from surge due to the fact that the interruption system is closed when the pot is detected, the IGBT module is easily damaged, the device cost of the electromagnetic heating appliance is increased, and the electromagnetic heating circuit cannot work normally.

In view of the above problems, the present embodiment provides an electromagnetic heating circuit, an electromagnetic heating appliance, and an electromagnetic heating circuit protection method, which can provide surge protection for the electromagnetic heating circuit while detecting a pot, so as to avoid the phenomenon that an IGBT module is damaged by surge interference when detecting a pot, reduce the device cost of the electromagnetic heating appliance, and improve the reliability of the heating circuit of an electromagnetic oven.

Next, a detailed description will be given of a specific structure of the electromagnetic heating circuit 100 by way of a specific example.

Fig. 1 is a schematic structural diagram of an electromagnetic heating circuit 100 provided in the present invention, and as shown in fig. 1, the electromagnetic heating circuit 100 of this embodiment may include: the circuit comprises a rectifying circuit 101, a filter circuit 102, a resonant circuit 103, an insulated gate bipolar transistor IGBT module 104, a drive circuit 105 and a control circuit 106.

The rectifier circuit 101 is configured to rectify an input power supply voltage, a positive output end of the rectifier circuit 101 is electrically connected to a first input end of the filter circuit 102, an output end of the filter circuit 102 and a first input end of the control circuit 106 are electrically connected to an input end of the resonant circuit 103, a drain of the IGBT module 104 and a second input end of the control circuit 106 are electrically connected to an output end of the resonant circuit 103, an output end of the control circuit 106 is electrically connected to an input end of the driving circuit 105, an output end of the driving circuit 105 is electrically connected to a gate of the IGBT module 104, and a negative output end of the rectifier circuit 101, a second input end of the filter circuit 102, and a source of the IGBT module 104 are all grounded.

In this embodiment, the rectifying circuit 101 may rectify an input power supply voltage, such as a commercial power, into a pulsating dc voltage, which is convenient for supplying a working voltage to the resonant circuit 103. The power supply voltage can be 220V, 50HZ single-phase sinusoidal alternating current voltage, and can also be mains supply after transformation, and this embodiment does not limit this, and only the type of the power supply voltage can satisfy various working requirements. The rectifying circuit 101 may be a full-bridge rectifier or a half-bridge rectifier, which is not limited in this embodiment.

In this embodiment, the first input terminal of the filter circuit 102 is electrically connected to the positive output terminal of the rectifier circuit 101, so that the pulsating dc voltage rectified by the rectifier circuit 101 can be filtered. The output terminal of the filter circuit 102 is electrically connected to the input terminal of the resonant circuit 103, so as to provide an operating voltage to the resonant circuit 103, which facilitates the start of heating of the resonant circuit 103, and thus the electromagnetic heating circuit 100 operates normally. In this embodiment, the specific implementation form of the filter circuit 102 is not limited, and only the filter circuit 102 has the functions of filtering and storing energy.

In this embodiment, the output end of the driving circuit 105 is electrically connected to the gate of the IGBT module 104, and the IGBT module 104 can be driven to turn on and off by the output driving signal. Based on the electrical connection relation between the output of resonant circuit 103 and the drain of IGBT module 104, consequently, resonant circuit 103 can be according to the on off state of IGBT module 104, and the transmission electromagnetic energy is treated the heating equipment and is heated, perhaps, stops the transmission electromagnetic energy and treats the heating equipment and heat to the power state of electromagnetic heating circuit 100 can be controlled to the on off state through IGBT module 104. In this embodiment, the specific number of the IGBT modules 104 is not limited.

In this embodiment, based on the parallel connection relationship between the control circuit 106 and the resonant circuit 103, the control circuit 106 may obtain the voltage at the first input terminal of the control circuit 106 and the voltage at the second input terminal of the control circuit 106, that is, the voltage at the first input terminal of the control circuit 106 is the voltage at the input terminal of the resonant circuit 103, and the voltage at the second input terminal of the control circuit 106 is the voltage at the output terminal of the resonant circuit 103.

Additionally, the control circuit 106 may alter the state of the first and second inputs of the control circuit 106. For example, the control circuit 106 may change the state of the first input terminal of the control circuit 106 to an output state, where the first input terminal of the control circuit 106 cannot receive a corresponding input signal from a component (e.g., the resonant circuit 103) electrically connected to the first input terminal of the control circuit 106. For another example, the control circuit 106 may change the state of the first input terminal of the control circuit 106 to an input state, and at this time, the first input terminal of the control circuit 106 may receive an input signal from a component (e.g., the resonant circuit 103) connected to the first input terminal of the control circuit 106.

It will be understood by those skilled in the art that when the electromagnetic heating circuit 100 is powered on, since the input terminal of the resonant circuit 103 is electrically connected to the supply voltage through the filter circuit 102 and the rectifier circuit 101, the voltage at the input terminal of the resonant circuit 103 is greater than the voltage at the output terminal of the resonant circuit 103, i.e. the voltage at the first input terminal of the control circuit 106 is greater than the voltage at the second input terminal of the control circuit 106.

Based on the above description, after the electromagnetic heating circuit 100 is powered on, a trigger instruction sent by a user may be received, where the trigger instruction is used to instruct the control circuit 106 to start the pot detection function. The present embodiment does not limit the implementation form of the electromagnetic heating circuit 100 receiving the trigger instruction. For example, a user can press a pot detection function button on the electromagnetic heating device 10 or activate a heating function button, such as a water boiling button, a hot pot button, a cooking button, etc., and a trigger command generated by the button includes a command instructing the control circuit 106 to activate the pot detection function, and the trigger command is transmitted to the electromagnetic heating circuit 100 from a preset port in the electromagnetic heating circuit 100. As another example, a user may send a trigger instruction to the electromagnetic heating circuit 100 through a terminal. The trigger instruction may be a digital signal or an analog signal, and the specific content of the trigger instruction is not limited in this embodiment.

Further, when the electromagnetic heating circuit 100 receives a trigger instruction, the control circuit 106 may change the state of the first input terminal or the state of the second input terminal of the control circuit 106 to an output state. Control circuit 106 may then control the voltage at the first input of control circuit 106 to be less than the voltage at the second input of control circuit 106. The control circuit 106 may pull down the voltage at the first input terminal of the control circuit 106 or may set up the voltage at the second input terminal of the control circuit 106, so as to implement a control process that the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106, which is not limited in this embodiment.

When the voltage on the first input of control circuit 106 is less than the voltage on the second input of control circuit 106, control circuit 106 may change the state of the first input or the state of the second input of control circuit 106 to an input state. Control circuit 106 may then cease controlling the voltage at the first input of control circuit 106 to be less than the voltage at the second input of control circuit 106. The control circuit 106 may stop pulling down the voltage at the first input terminal of the control circuit 106 or stopping pulling up the voltage at the second input terminal of the control circuit 106, so as to implement a control process that the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106, which is not limited in this embodiment.

The first input of the control circuit 106 is electrically connected to the input of the resonant circuit 103, so that the voltage at the first input of the control circuit 106 can be varied as the voltage at the input of the resonant circuit 103 is varied. The second input of the control circuit 106 is electrically connected to the output of the resonant circuit 103, such that the voltage at the second input of the control circuit 106 may vary with the voltage at the output of the resonant circuit 103. Moreover, since the heating circuit 100 of the induction cooker normally operates, the voltage at the input terminal of the resonant circuit 103 is greater than the voltage at the output terminal of the resonant circuit 103, and therefore, the voltage at the first input terminal of the control circuit 106 gradually changes from being smaller than the voltage at the second input terminal of the control circuit 106 to being greater than or equal to the voltage at the second input terminal of the control circuit 106, so that the voltage at the first input terminal of the control circuit 106 is greater than or equal to the voltage at the second input terminal of the control circuit 106.

In this application, when the voltage at the first input end of the control circuit 106 is greater than or equal to the voltage at the second input end of the control circuit 106, the control circuit 106 may continuously send a pan detection signal to the driving circuit 105, where the pan detection signal is used to detect whether there is a device to be heated on the electromagnetic heating appliance 10, so that the driving circuit 105 may continuously drive the IGBT module 104 to be turned on according to the pan detection signal.

The pot detection signal is a pulse signal, which may be a high level or a low level, and this embodiment does not limit this.

As will be appreciated by those skilled in the art, the electromagnetic heating circuit 100 is typically about 8 microseconds long in pot check. Therefore, the preset width of the pan detection signal can be freely and flexibly set according to the actual situation of the electromagnetic heating device 10, and can be preset in the control circuit 106, or can be set by the user according to the expectation and manually input into the control circuit 106, which is not limited in this embodiment. In addition, the preset width is used for representing the sending time length of the pot detection signal. In general, the preset width may represent any one duration from 4 microseconds to 8 microseconds.

In this application, when detecting that the output width of the pan detection signal is greater than or equal to the preset width, the control circuit 106 may stop sending the pan detection signal to the driving circuit 105, and send a pan detection stop signal to the driving circuit 105, where the pan detection stop signal is used to stop detecting whether there is a device to be heated on the electromagnetic heating appliance 10, so that the driving circuit 105 may drive the IGBT module 104 to turn off according to the pan detection stop signal.

In the above process, by detecting various parameters in the electromagnetic heating circuit 100, such as the current in the resonant circuit 103, the voltage across the resonant circuit 103, the real-time temperature, the real-time pressure, and the like, it can be known whether the equipment to be heated is on the electromagnetic heating appliance 10, so as to complete the pot detection process of the electromagnetic heating circuit 100. In addition, in the present embodiment, whether the device to be heated on the electromagnetic heating device 10 is suitable can be determined according to the various parameters, such as meeting the industry standards of parameters such as temperature and pressure.

The pot detection stopping signal can be a high level or a low level, and the embodiment does not limit the pot detection stopping signal, and only the pot detection stopping signal and the pot detection signal need to be opposite in level.

The rectifier circuit 101, the filter circuit 102, the resonant circuit 103, the driving circuit 105, and the control circuit 106 may be integrated chips, or may be circuits built by a plurality of components, which is not limited in this embodiment.

In a specific embodiment, taking the electromagnetic heating appliance 10 as an electromagnetic oven, the electromagnetic oven including the structure of the electromagnetic heating circuit 100 shown in fig. 1, the device to be heated is a pot, and the preset width represents a pot detection time duration of about 8 microseconds as an example, the specific process of detecting the pot by using the electromagnetic heating circuit 100 of this embodiment is as follows:

step 1, a user powers on the induction cooker. After power-up, when the electromagnetic heating circuit 100 is in a quiescent state, the voltage at the first input terminal of the control circuit 106 is greater than the voltage at the second input terminal of the control circuit 106.

And 2, when the electromagnetic heating circuit 100 receives a trigger instruction, the control circuit 106 starts to detect the pot.

Step 3, when the control circuit 106 starts to detect the pan, the control circuit 106 may change the state of the first input terminal or the state of the second input terminal of the control circuit 106 to the output state.

Step 4, the control circuit 106 may change the voltage at the first input terminal of the control circuit 106 or the voltage at the second input terminal of the control circuit 106, so as to control the voltage at the first input terminal of the control circuit 106 to be smaller than the voltage at the second input terminal of the control circuit 106.

Step 5, when the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106, the control circuit 106 may change the state of the first input terminal or the state of the second input terminal of the control circuit 106 to the input state.

Step 6, the control circuit 106 may stop changing the voltage at the first input terminal of the control circuit 106 or the voltage at the second input terminal of the control circuit 106, so as to stop controlling the voltage at the first input terminal of the control circuit 106 to be smaller than the voltage at the second input terminal of the control circuit 106.

Step 7, since the heating circuit 100 of the induction cooker normally operates, the voltage at the input terminal of the resonant circuit 103 is greater than the voltage at the output terminal of the resonant circuit 103, and therefore, the voltage at the first input terminal of the control circuit 106 gradually changes from being smaller than the voltage at the second input terminal of the control circuit 106 to being greater than or equal to the voltage at the second input terminal of the control circuit 106, so that the voltage at the first input terminal of the control circuit 106 is greater than or equal to the voltage at the second input terminal of the control circuit 106.

Step 8, when the voltage at the first input end of the control circuit 106 is greater than or equal to the voltage at the second input end of the control circuit 106, the control circuit 106 may send a low level to the driving circuit 105, so that the driving circuit 105 may input a driving voltage of 18V to the IGBT module 104 through level conversion of the driving circuit 105 to drive the IGBT module 104 to conduct. After the IGBT module 104 is turned on, the resonant circuit 103 charges and accumulates energy.

Step 9, when the output width of the low level is greater than or equal to the preset width, the control circuit 106 may send a high level to the driving circuit 105, so that the driving circuit 105 may drive the IGBT module 104 to turn off.

And step 10, based on the steps, whether the cooker is on the induction cooker can be known through the waveform curves of parameters such as current, voltage and temperature in the induction cooker, and the electromagnetic pot detection process is completed.

For example, because the control circuit 106 is connected in parallel at the two ends of the resonant circuit 103 through the control circuit 106, and the current direction changes when the resonance is at the lowest point, therefore, the control circuit 106 can detect the number of times of the change of the circuit direction, and determine whether a pot is placed on the induction cooker.

Compared with the conventional electromagnetic heating circuit 100, the electromagnetic heating circuit 100 of the embodiment does not need to turn off a relay system providing surge protection when the pot is detected, so that the phenomenon that the IGBT module 104 is damaged due to surge interference is avoided, the device cost of the electromagnetic heating circuit 100 is reduced, and the reliability of the electromagnetic heating circuit 100 is improved.

The electromagnetic heating circuit provided by the embodiment can start to detect the pot by the control circuit when receiving the trigger instruction. When the pot is detected, the control circuit can change the state of the first input end or the state of the second input end of the control circuit into an output state. The control circuit can control the voltage on the first input end of the control circuit to be smaller than the voltage on the second input end of the control circuit by changing the voltage on the first input end or the second input end of the control circuit. The control circuit may then change the state of the first input terminal or the state of the second input terminal of the control circuit to the input state. The control circuit may stop controlling the voltage at the first input terminal of the control circuit to be less than the voltage at the second input terminal of the control circuit by stopping changing the voltage at the first input terminal or the second input terminal of the control circuit. The first input terminal of the control circuit is electrically connected with the input terminal of the resonant circuit, so that the voltage at the first input terminal of the control circuit can be changed along with the change of the voltage at the input terminal of the resonant circuit. The second input terminal of the control circuit is electrically connected with the output terminal of the resonant circuit, so that the voltage on the second input terminal of the control circuit can be changed along with the change of the voltage on the output terminal of the resonant circuit. In the normal operation process of the electromagnetic heating circuit, the voltage at the input end of the resonant circuit is greater than the voltage at the output end of the resonant circuit, so that the voltage at the first input end of the control circuit is gradually changed from being smaller than the voltage at the second input end of the control circuit to being greater than or equal to the voltage at the second input end of the control circuit. Therefore, when the voltage on the first input end of the control circuit is larger than or equal to the voltage on the second input end of the control circuit, the control circuit can continuously send a pot detection signal to the drive circuit, so that the drive circuit can continuously drive the IGBT module to be conducted according to the pot detection signal. When the output width of the pot detection signal is larger than or equal to the preset width, the control circuit can stop sending the pot detection signal to the driving circuit and send the pot detection stopping signal to the driving circuit, so that the driving circuit can drive the IGBT module to be disconnected according to the pot detection stopping signal. And then, by collecting various parameters of the electromagnetic heating circuit in the process, determining whether the electromagnetic heating appliance comprising the electromagnetic heating circuit is provided with equipment to be heated or not so as to finish the pot detection process of the electromagnetic heating circuit.

In the embodiment, the control circuit is triggered through the resonant circuit, a relay system for providing surge protection is not required to be turned off when the pot is detected, the pot detection process and the surge protection process of the electromagnetic heating circuit are realized simultaneously, the phenomenon that an IGBT module is damaged due to surge interference is avoided, the device cost of the electromagnetic heating circuit is reduced, and the reliability of the electromagnetic heating circuit is improved. In addition, the width of the pot detection signal can be flexibly and freely set, and the software program of the electromagnetic heating circuit is simplified.

It should be noted that when the electromagnetic heating circuit 100 detects that the equipment to be heated is on the electromagnetic heating appliance 10, the electromagnetic heating circuit 100 can be switched to the normal heating operation. When the electromagnetic heating circuit 100 does not detect the device to be heated on the electromagnetic heating appliance 10, the electromagnetic heating circuit 100 may continue to detect whether the device to be heated is on the electromagnetic heating appliance 10 for a preset time period. If the electromagnetic heating circuit 100 does not detect the equipment to be heated on the electromagnetic heating appliance 10 after the preset time period, the electromagnetic heating circuit 100 may stop starting.

The preset duration may be set according to an actual situation, which is not limited in this embodiment.

Next, a detailed description will be given of a specific configuration included in the electromagnetic heating circuit 100 of the present embodiment, in addition to the embodiment of fig. 1, with reference to fig. 2 to 6.

As shown in fig. 2, optionally, the control circuit 106 of this embodiment may include: a synchronous comparator circuit 1061, a Pulse Program Generator (PPG) output control circuit 1062, a voltage divider circuit 1063, and a Micro Control Unit (MCU) 1064.

A control end of the MCU1064 is electrically connected to a target end of the synchronous comparator circuit 1061, a target end of the synchronous comparator circuit 1061 is a co-directional input end PA1 or an inverting input end PA0 of the synchronous comparator circuit 1061, a first input end of the voltage divider circuit 1063 is electrically connected to an input end of the resonant circuit 103, a second input end of the voltage divider circuit 1063 is electrically connected to an output end of the resonant circuit 103, a first output end of the voltage divider circuit 1063 is electrically connected to a co-directional input end PA1 of the synchronous comparator circuit 1061, a second output end of the voltage divider circuit 1063 is electrically connected to an inverting input end PA0 of the synchronous comparator circuit 1061, an output end of the synchronous comparator circuit 1061 is electrically connected to an input end of the PPG output control circuit 1062, and an output end of the PPG output control circuit 1062 is electrically connected to an input end of the PPG.

It will be understood by those skilled in the art that when the electromagnetic heating circuit is in a quiescent state after the electromagnetic heating appliance 10 is powered on, the voltage at the inverting input PA1 of the synchronous comparator circuit 1061 is greater than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061. Based on this content, the MCU1064 in this embodiment starts to detect the pan when receiving the trigger command. When the pan detection is started, the MCU1064 may control the target of the synchronous comparator circuit 1061 to be in an output state, and change the voltage at the target of the synchronous comparator circuit 1061 such that the voltage at the equidirectional input PA1 of the synchronous comparator circuit 1061 is lower than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061.

In this embodiment, when the voltage at the unidirectional input terminal PA1 of the synchronous comparator circuit 1061 is less than the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061, the synchronous comparator circuit 1061 may output a first signal to the PPG control output voltage.

The first signal is a digital signal, and may be a high level or a low level, which is not limited in this embodiment. Typically, the first signal is at a low level, i.e. a logic "0".

In addition, when the voltage at the equidirectional input terminal PA1 of the synchronous comparator circuit 1061 is lower than the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061, the MCU1064 can further control the target terminal of the synchronous comparator circuit 1061 to be in an input state and stop changing the voltage at the target terminal of the synchronous comparator circuit 1061, so that the voltage at the equidirectional input terminal PA1 of the synchronous comparator circuit 1061 can send a change along with the change of the voltage at the input terminal of the resonant circuit 103, and the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061 can change along with the change of the voltage at the output terminal of the resonant circuit 103, so that since the voltage at the input terminal of the resonant circuit 103 is higher than the voltage at the output terminal of the resonant circuit 103 and the equidirectional input terminal PA1 of the synchronous comparator circuit 1061 is electrically connected with the input terminal of the resonant circuit 103, the inverting input terminal PA0 of the synchronous comparator circuit 1061 is electrically connected with the output terminal, therefore, the voltage at the inverting input PA1 of the synchronous comparator circuit 1061 gradually changes from being lower than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 to being equal to or higher than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061, so that the voltage at the inverting input PA1 of the synchronous comparator circuit 1061 can be increased to be equal to or higher than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061.

In this embodiment, when the voltage at the unidirectional input terminal PA1 of the synchronous comparator circuit 1061 is greater than or equal to the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061, the synchronous comparator circuit 1061 may output a trigger signal with a level opposite to that of the first signal to the PPG control output circuit.

The trigger signal is a digital signal, and may be a high level or a low level, which is not limited in this embodiment. Typically, the trigger signal is high, i.e. logic "1".

Based on the rising edge or the falling edge formed by the first signal and the trigger signal, the trigger PPG output control circuit 1062 may continuously send a pan detection signal to the drive circuit 105, so that the drive circuit 105 may continuously drive the IGBT module 104 to conduct according to the pan detection signal.

In this embodiment, the PPG output control circuit 1062 may set a preset width in advance, or may receive a preset width input by a user, which is not limited in this embodiment. For example, a PPG output width register inside the PPG output control circuit 1062 may set a preset width.

Further, the PPG output control circuit 1062, such as a counter inside the PPG output width register, may start timing the output width of the pot detection signal when sending the pot detection signal. Therefore, when the output width of the pot detection signal is greater than or equal to the preset width, the PPG output control circuit 1062 may output a pot detection stop signal to the driving circuit 105, so that the driving circuit 105 may drive the IGBT module 104 to turn off according to the pot detection stop signal.

Next, a specific implementation process of the synchronous comparator circuit 1061 outputting the first signal and the trigger signal will be described from two aspects, that is, the target terminal of the synchronous comparator circuit 1061 is the unidirectional input PA1 of the synchronous comparator circuit 1061 and the target terminal of the synchronous comparator circuit 1061 is the inverse input PA0 of the synchronous comparator circuit 1061.

On the one hand, when the target terminal of the synchronous comparator circuit 1061 is the unidirectional input terminal PA1 of the synchronous comparator circuit 1061, as shown in fig. 3a and fig. 4, when receiving the trigger instruction, the MCU1064 may control the unidirectional input terminal PA1 of the synchronous comparator circuit 1061 to be in the output state, and pull down the voltage at the unidirectional input terminal PA1 of the synchronous comparator circuit 1061 (corresponding to the curve 1 at the time t1 in fig. 3 a), so that the voltage at the unidirectional input terminal PA1 of the synchronous comparator circuit 1061 is smaller than the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061 (corresponding to the curve 2 at the time t1 in fig. 3 a), and at this time, the synchronous comparator circuit 1061 may output the first signal to the PPG control output voltage.

When the voltage at the unidirectional input PA1 of the synchronous comparator circuit 1061 is lower than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061, the MCU1064 may control the target of the synchronous comparator circuit 1061 to be in the input state and stop pulling down the voltage at the unidirectional input PA1 of the synchronous comparator circuit 1061, so that the voltage at the unidirectional input PA1 of the synchronous comparator circuit 1061 may continuously rise as the voltage at the input of the resonant circuit 103 increases. As the voltage at the non-inverting input PA1 of the synchronous comparator circuit 1061 continuously rises (corresponding to curve 1 at time t1-t2 in fig. 3 a), the synchronous comparator circuit 1061 may output a trigger signal to the PPG control output circuit that is opposite to the first signal level when the voltage at the non-inverting input PA1 of the synchronous comparator circuit 1061 (corresponding to curve 1 at time t2 in fig. 3 a) is greater than or equal to the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 (corresponding to curve 1 at time t2 in fig. 3 a).

Based on the rising edge of the first signal and the trigger signal, the PPG output control circuit 1062 may be triggered to continuously send a pot detection signal (corresponding to curve 1 in the time period t2-t3 in fig. 4) to the driving circuit 105, so that the driving circuit 105 may continuously drive the IGBT module 104 to conduct according to the pot detection signal, wherein the voltage on the drain of the IGBT module 104 (corresponding to curve 2 in the time period t2-t3 in fig. 4).

Further, the PPG output control circuit 1062 starts to time the output width of the pot detection signal when sending the pot detection signal, and determines whether the output width of the pot detection signal is greater than or equal to a preset width (corresponding to the time period t2-t3 in fig. 4). When the output width of the pan detection signal is greater than or equal to the preset width (corresponding to time t3 in fig. 4), the PPG output control circuit 1062 may output a stop pan detection signal (corresponding to curve 1 after time t3 in fig. 4) to the drive circuit 105, so that the drive circuit 105 may drive the IGBT module 104 to turn off according to the stop pan detection signal, where the voltage on the drain of the IGBT module 104 (corresponding to curve 2 after time t3 in fig. 4).

On the other hand, when the target terminal of the synchronous comparator circuit 1061 is the inverting input terminal PA0 of the synchronous comparator circuit 1061, as shown in fig. 3b and fig. 4, when receiving the trigger instruction, the MCU1064 may control the inverting input terminal PA0 of the synchronous comparator circuit 1061 to be in the output state, and set the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061 high (corresponding to curve 1 at time t1 in fig. 3 b), so that the voltage at the inverting input terminal PA1 of the synchronous comparator circuit 1061 is smaller than the voltage at the inverting input terminal PA0 of the synchronous comparator circuit 1061 (corresponding to curve 2 at time t1 in fig. 3 b), and at this time, the synchronous comparator circuit 1061 may output the first signal to the PPG control output voltage.

When the voltage at the inverting input PA1 of the synchronous comparator circuit 1061 is lower than the voltage at the inverting input PA0 of the synchronous comparator circuit 1061, the MCU1064 may control the target of the synchronous comparator circuit 1061 to be in an input state and stop raising the voltage at the inverting input PA0 of the synchronous comparator circuit 1061, so that the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 may be continuously lowered as the voltage at the output of the resonant circuit 103 is reduced. As the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 continuously decreases (corresponding to curve 1 at time t1-t2 in fig. 3 b), the synchronous comparator circuit 1061 may output a trigger signal to the PPG control output circuit that is opposite to the first signal level when the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 (corresponding to curve 1 at time t2 in fig. 3 b) is greater than or equal to the voltage at the inverting input PA0 of the synchronous comparator circuit 1061 (corresponding to curve 1 at time t2 in fig. 3 b).

Compared with the conventional electromagnetic heating circuit 100, the electromagnetic heating circuit 100 of the present embodiment changes the state of the positive input PA1 or the input PA0 of the synchronous comparator circuit 1061, and changes the voltage at the positive input PA1 or the input PA0 of the synchronous comparator circuit 1061, so that the voltage at the positive input PA1 of the synchronous comparator circuit 1061 is smaller than the voltage at the input PA 0. Furthermore, because the voltage at the input end of the resonant circuit 103 is greater than the voltage at the output end of the resonant circuit 103, and the synchronous comparator circuit 1061 is connected in parallel to the two ends of the resonant circuit, the signal at the output end of the synchronous comparator is inverted, so as to trigger the PPG output control circuit 1062 to send a pot detection signal to the driving circuit 105, so as to drive the IGBT module 104 to be turned on. At this time, the PPG output control circuit 1062 starts timing the output width of the pot detection signal to determine whether the output width of the pot detection signal is greater than or equal to a preset width. When the output width of the pot detection signal is greater than or equal to the preset width, the PPG output control circuit 1062 stops sending the pot detection signal to the drive circuit 105, and sends the pot detection stop signal to the drive circuit 105 to drive the IGBT module 104 to be turned off, thereby completing the pot detection process of the electromagnetic heating circuit 100.

Based on the above description, the electromagnetic heating circuit 100 of the present application does not need to turn off the relay system in the control circuit 106 when detecting the pot, so that the IGBT module 104 can be turned off even if surge interference occurs in the pot, damage to the IGBT module 104 due to the surge interference is avoided, the lifetime of the IGBT module 104 is delayed, and the device cost of the IGBT module 104 is saved.

It should be noted that the voltage divider 1063 may be a separate module, or may be disposed in the control circuit 106 as an internal module of the control circuit 106, which is not limited in this embodiment. In addition, in fig. 2, a filter capacitor C4 may be connected in parallel to the first input terminal and the second input terminal of the rectifier circuit 101 to perform a filtering function.

With reference to fig. 2, since the input terminal of the synchronous comparator circuit 1061 in the same direction is electrically connected to the first output terminal of the voltage divider circuit 1063, the input terminal of the synchronous comparator circuit 1061 in the opposite direction is electrically connected to the second output terminal of the voltage divider circuit 1063, and the resonant circuit 103 resonates after the IGBT module 104 is turned off, the signal at the output terminal of the synchronous comparator circuit 1061 is inverted every time the resonant circuit 103 resonates to the lowest point.

As shown in fig. 2, the input terminal of the MCU1064 is electrically connected to the output terminal of the synchronous comparator circuit 1061, so as to obtain the number of times of flipping of the synchronous comparator circuit 1061, and determine whether the electromagnetic heating apparatus 10 is to be heated according to the number of times of flipping. In general, when the electromagnetic heating device 10 is provided with equipment to be heated, the turnover number is small. Therefore, the MCU1064 may be preset with a threshold, which may be the number of flips of the synchronous comparator circuit 1061 when there is no equipment to be heated on the electromagnetic heating apparatus 10, or the number of flips of the synchronous comparator circuit 1061 when there is equipment to be heated on the electromagnetic heating apparatus 10.

In this embodiment, the driving circuit 105 may include various implementations. In a possible implementation structure, as shown in fig. 2, the driving circuit 105 of the present embodiment may optionally include: the circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first triode Q1, a second triode Q2, a third triode Q3 and a first capacitor C1.

Wherein, the first end of the first resistor R1, the first end of the third resistor R3 and the drain of the second transistor Q2 are connected with a preset level, the output end of the control circuit 106 is electrically connected between the second end of the first resistor R1 and the first end of the second resistor R2, the second end of the first resistor R1 is electrically connected with the first end of the second resistor R2, the second end of the second resistor R2 is electrically connected with the gate of the first transistor Q1, the second end of the third resistor R3 is electrically connected with the drain of the first transistor Q1 and the gate of the second transistor Q2, respectively, the first end of the first capacitor C1 is electrically connected between the drain of the first transistor Q1 and the gate of the third transistor Q3, the second end of the first capacitor C1, the source of the first transistor Q1 and the drain of the third transistor Q3 are all grounded, the source of the second transistor Q2 is electrically connected with the first end of the fourth resistor R5, the source of the fourth resistor R4 is electrically connected with the source of the third transistor Q57324, the gate of the IGBT module 104 is electrically connected between the second end of the fourth resistor R4 and the source of the third transistor Q3.

In this embodiment, specific values and numbers of the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the first transistor Q1, the second transistor Q2, the third transistor Q3, and the first capacitor C1 may be set according to actual situations, which is not limited in this embodiment. For convenience of illustration, in fig. 2, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the first transistor Q1, the second transistor Q2, the third transistor Q3, and the first capacitor C1 are illustrated as an example.

In order to avoid the voltage input to the gate of the IGBT module 104 by the driving circuit 105 being too high, in this embodiment, the electromagnetic heating circuit 100 may be provided with a protection chip or a protection circuit 107 constructed by a plurality of components between the driving circuit 105 and the IGBT module 104 to perform a voltage division function, so that the IGBT module 104 can normally operate.

In the present application, the protection circuit 107 may include various implementations. In a possible implementation structure, as shown in fig. 2, optionally, the protection circuit 107 of this embodiment may include: a fifth resistor R5, a sixth resistor R6 and a zener diode DW 1.

The output end of the driving circuit 105 is electrically connected to the first end of the zener diode DW1 and the first end of the fifth resistor R5, the second end of the fifth resistor R5 is electrically connected to the first end of the sixth resistor R6 and the gate of the IGBT module 104, and the second end of the zener diode DW1, the second end of the sixth resistor R6 and the source of the IGBT module 104 are all grounded.

The present embodiment may set specific values and numbers of the fifth resistor R5, the sixth resistor R6, and the zener diode DW1 according to practical situations, which is not limited in the present embodiment. For convenience of illustration, the fifth resistor R5, the sixth resistor R6 and the zener diode DW1 are illustrated as an example in fig. 2.

In this embodiment, the resonant circuit 103 may include various implementations. In one possible implementation structure, as shown in fig. 2, the resonant circuit 103 of the present embodiment may optionally include: a second capacitance C2 and a resonant inductance L1.

The output end of the filter circuit 102 and the first input end of the control circuit 106 are electrically connected to the first end of the resonant inductor L1, the drain of the IGBT module 104 and the second input end of the control circuit 106 are electrically connected to the second end of the resonant inductor L1, and the second capacitor C2 is connected in parallel to the resonant inductor.

The specific values and the number of the second capacitor C2 and the resonant inductor L1 may be set according to actual conditions, which is not limited in this embodiment. For convenience of illustration, the second capacitor C2 and the resonant inductor L1 are illustrated in fig. 2 as an example. The resonant inductor L1 may be made of a magnetic material such as ferrite, iron silicon, or iron silicon aluminum.

In this embodiment, the voltage divider circuit 1063 may include various implementations. In a possible implementation structure, as shown in fig. 2, optionally, the voltage dividing circuit 1063 of this embodiment may include: a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10.

A first end of the seventh resistor R7 is electrically connected to the input end of the resonant circuit 103, a first end of the eighth resistor R8 is electrically connected to the output end of the resonant circuit 103, a second end of the seventh resistor R7 is electrically connected to a first end of the ninth resistor R9, a second end of the eighth resistor R8 is electrically connected to a first end of the tenth resistor R10, a second end of the ninth resistor R9 and a second end of the tenth resistor R10 are both grounded, a first input end of the control circuit 106 is electrically connected between a second end of the seventh resistor R7 and a first end of the ninth resistor R9, and a second input end of the control circuit 106 is electrically connected between a second end of the eighth resistor R8 and a first end of the tenth resistor R10.

In this embodiment, specific values and numbers of the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 may be set according to actual situations, which is not limited in this embodiment. For convenience of illustration, fig. 2 illustrates the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 as one example.

In this embodiment, the filter circuit 102 may include various implementations. In a possible implementation structure, as shown in fig. 2, optionally, the filter circuit 102 of the present embodiment may include: a third capacitor C3.

A first end of the third capacitor C3 is electrically connected between the forward output end of the rectifier circuit 101 and the input end of the resonant circuit 103, and a second end of the third capacitor C3 is grounded.

In this embodiment, specific values and numbers of the third capacitor C3 may be set according to actual situations, which is not limited in this embodiment. For convenience of illustration, the third capacitors C3 are illustrated in fig. 2 as an example. In addition, the filter circuit 102 may include implementation structures such as a filter inductor and a filter capacitor, in addition to the implementation structures described above.

In this embodiment, the electromagnetic heating circuit 100 further includes a surge protection function, which may be implemented by software, hardware, or both, and this embodiment is not limited thereto.

Next, a specific implementation structure of the electromagnetic heating circuit 100 of the present embodiment is described with reference to fig. 5.

Fig. 5 is a schematic structural diagram of an electromagnetic heating circuit provided in the present invention, and as shown in fig. 5, optionally, the electromagnetic heating circuit 100 of this embodiment may further include: a surge detection circuit 109.

A first input terminal of the surge detection circuit 109 is electrically connected to a first input terminal of the rectifier circuit 101, a second input terminal of the surge detection circuit 109 is electrically connected to a second input terminal of the rectifier circuit 101, and an output terminal of the surge detection circuit 109 is electrically connected to a third input terminal of the control circuit 106.

In this embodiment, the surge detection circuit 109 is electrically connected to the input side of the rectifier circuit 101, and can acquire the power supply voltage and send a surge signal to the control circuit 106 when surge interference is detected in the power supply voltage. Therefore, when receiving the surge signal, the control circuit 106 does not need to consider the current state of the electromagnetic heating circuit 100, and even if the electromagnetic heating circuit 100 detects a pot, the control circuit can send a pot detection stop signal to the driving circuit 105 to prevent the IGBT module 104 from being damaged.

In this embodiment, the surge detection circuit 109 may include multiple implementation manners, may be an integrated chip, and may also be a circuit built by multiple components, which is not limited in this embodiment. In a possible implementation structure, as shown in fig. 6, optionally, the surge detection circuit 109 of this embodiment may include: a first diode D1, a second diode D2, an eleventh resistor R11, and a twelfth resistor R12.

The anode of the first diode D1 is electrically connected to the first input terminal of the rectifier circuit 101, the anode of the second diode D2 is electrically connected to the second input terminal of the rectifier circuit 101, the cathode of the first diode D1 and the cathode of the second diode D2 are respectively electrically connected to the first end of the eleventh resistor R11, the second end of the eleventh resistor R11 is electrically connected to the first end of the twelfth resistor R12, the second end of the twelfth resistor R12 is grounded, and the third input terminal of the control circuit 106 is electrically connected between the second end of the eleventh resistor R11 and the first end of the twelfth resistor R12.

In this embodiment, specific values and numbers of the first diode D1, the second diode D2, the eleventh resistor R11, and the twelfth resistor R12 may be set according to actual situations, which is not limited in this embodiment. For convenience of illustration, the first diode D1, the second diode D2, the eleventh resistor R11, and the twelfth resistor R12 are illustrated in fig. 6 as an example.

Fig. 7 is a schematic structural diagram of an electromagnetic heating apparatus provided in the present invention, and as shown in fig. 7, the electromagnetic heating apparatus 10 of the present embodiment may include: the electromagnetic heating circuit 100 described above.

The electromagnetic heating device 10 may include, but is not limited to, various devices requiring heating, such as an electromagnetic oven, an electric rice cooker, an electric pressure cooker, a soybean milk machine, a coffee machine, and a blender.

The electromagnetic heating device 10 provided in this embodiment includes the electromagnetic heating circuit 100, and the above embodiments can be implemented, and specific implementation principles and technical effects thereof can be seen in the technical solutions of the embodiments in fig. 1 to 6, which are not described herein again.

Fig. 8 is a schematic flow chart of a protection method for an electromagnetic heating circuit according to the present invention. As shown in fig. 8, the protection method of the electromagnetic heating circuit 100 of the present embodiment is applied to the electromagnetic heating circuit 100 of fig. 1 to 6. The protection method of the electromagnetic heating circuit 100 of the embodiment includes:

s101, when a trigger instruction is received, the voltage on the first input end of the control circuit 106 is smaller than the voltage on the second input end of the control circuit 106, and the trigger instruction is used for indicating the control circuit 106 to start pot detection.

S102, when the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106, controlling the voltage at the first input terminal of the control circuit 106 to be greater than or equal to the voltage at the second input terminal of the control circuit 106.

And S1031, when the voltage on the first input end of the control circuit 106 is greater than or equal to the voltage on the second input end of the control circuit 106, sending a pot detection signal to the drive circuit 105, so that the drive circuit 105 drives the IGBT module 104 to be conducted according to the pot detection signal, and the pot detection signal is used for detecting whether equipment to be heated is arranged on the electromagnetic heating appliance 10.

S1032, when the pan detection signal is sent to the driving circuit 105, the output width of the pan detection signal starts to be timed, and when the output width of the pan detection signal is greater than or equal to the preset width, the pan detection stop signal is sent to the driving circuit 105, so that the driving circuit 105 drives the IGBT module 104 to turn off according to the pan detection stop signal, the pan detection stop signal is used to stop detecting whether the electromagnetic heating device 10 is to be heated, and the levels of the pan detection stop signal and the pan detection stop signal are opposite.

With reference to fig. 1 to 6, the protection method of the electromagnetic heating circuit 100 of the present embodiment may use the control circuit 106 in the electromagnetic heating circuit 100 as an execution main body, and a specific process may execute the above embodiment, and specific implementation principles and technical effects thereof may refer to the technical solutions of the embodiments shown in fig. 1 to 6, which are not described herein again.

In fig. 8, the control circuit 106 can regulate the magnitude relationship between the voltage at the first input terminal of the control circuit 106 and the voltage at the second input terminal of the control circuit 106 in a variety of ways.

Alternatively, when the target of the control circuit 106 is the first input of the control circuit 106 or the second input of the control circuit 106, the control circuit 106 may control the target of the control circuit 106 to be in the output state and change the voltage on the target of the control circuit 106 so that the voltage on the first input of the control circuit 106 is smaller than the voltage on the second input of the control circuit 106. Furthermore, when the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106, the control circuit 106 may control the target terminal of the control circuit 106 to be in an input state, and stop changing the voltage at the target terminal of the control circuit 106, so that the voltage at the first input terminal of the control circuit 106 may change with the change of the voltage at the input terminal of the resonant circuit, and the voltage at the second input terminal of the control circuit 106 may also change with the change of the voltage at the output terminal of the resonant circuit 103, so that the voltage at the first input terminal of the control circuit 106 is greater than or equal to the voltage at the second input terminal of the control circuit 106.

In one aspect, when the target of the control circuit 106 is the first input of the control circuit 106, the control circuit 106 may control the first input of the control circuit 106 to be in the output state and pull down the voltage at the first input of the control circuit 106, so that the voltage at the first input of the control circuit 106 is smaller than the voltage at the second input of the control circuit 106. Further, when the voltage at the first input terminal of the control circuit 106 is less than the voltage at the second input terminal of the control circuit 106, the control circuit 106 may control the first input terminal of the control circuit 106 to be in an input state, and stop pulling down the voltage at the first input terminal of the control circuit 106, so that the voltage at the first input terminal of the control circuit 106 is greater than or equal to the voltage at the second input terminal of the control circuit 106.

On the other hand, when the target terminal of the control circuit 106 is the second input terminal of the control circuit 106, the control circuit 106 may control the second input terminal of the control circuit 106 to be in the output state, and set the voltage at the second input terminal of the control circuit 106 high, so that the voltage at the first input terminal of the control circuit 106 is smaller than the voltage at the second input terminal of the control circuit 106. Further, when the voltage at the first input terminal of the control circuit 106 is less than the voltage at the second input terminal of the control circuit 106, the control circuit 106 may control the second input terminal of the control circuit 106 to be in the input state and stop raising the voltage at the second input terminal of the control circuit 106, so that the voltage at the first input terminal of the control circuit 106 is greater than or equal to the voltage at the second input terminal of the control circuit 106.

It should be noted that, the above implementation process may specifically refer to the description that the MCU1064 in the control circuit 106 shown in fig. 1 to 6 changes the magnitude relationship between the voltage at the equidirectional input end of the synchronous comparator circuit 1061 and the voltage at the inverted input end of the synchronous comparator circuit 1061, and is not described herein again.

In addition, on the basis of the above-described embodiment shown in fig. 8, optionally, in the process of executing S101, S102, S1031 and S1032 by the control circuit 106, the surge detection circuit 108 may transmit a surge signal to the control circuit 106 when detecting that there is surge interference in the power supply voltage. Therefore, when receiving the surge signal, the control circuit 106 can send a pot detection stopping signal to the driving circuit 105 to prevent the IGBT module 104 from being damaged.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An electromagnetic heating circuit (100), comprising: the circuit comprises a rectifying circuit (101), a filter circuit (102), a resonant circuit (103), an Insulated Gate Bipolar Transistor (IGBT) module (104), a driving circuit (105) and a control circuit (106);

wherein the rectifying circuit (101) is used for rectifying the input power supply voltage, the positive output end of the rectifying circuit (101) is electrically connected with the first input end of the filter circuit (102), an output of the filter circuit (102) and a first input of the control circuit (106) are electrically connected to an input of the resonance circuit (103), respectively, the drain electrode of the IGBT module (104) and the second input end of the control circuit (106) are respectively electrically connected with the output end of the resonance circuit (103), the output end of the control circuit (106) is electrically connected with the input end of the drive circuit (105), the output end of the driving circuit (105) is electrically connected with the grid of the IGBT module (104), the negative output end of the rectifying circuit (101), the second input end of the filter circuit (102) and the source electrode of the IGBT module (104) are all grounded;

the control circuit (106) is used for controlling the voltage on the first input end of the control circuit (106) to be smaller than the voltage on the second input end of the control circuit (106) when a trigger instruction is received, and the trigger instruction is used for indicating the control circuit (106) to start pot detection;

the control circuit (106) is further configured to control the voltage at the first input terminal of the control circuit (106) to be greater than or equal to the voltage at the second input terminal of the control circuit (106) when the voltage at the first input terminal of the control circuit (106) is less than the voltage at the second input terminal of the control circuit (106); when the voltage on the first input end of the control circuit (106) is greater than or equal to the voltage on the second input end of the control circuit (106), sending a pot detection signal to the drive circuit (105), wherein the pot detection signal is used for detecting whether equipment to be heated is arranged on the electromagnetic heating appliance (10); when the output width of the pot detection signal is larger than or equal to a preset width, sending a pot detection stopping signal to the driving circuit (105), wherein the pot detection stopping signal is used for stopping detecting whether the electromagnetic heating appliance (10) is provided with the equipment to be heated, and the pot detection signal and the pot detection stopping signal have opposite levels;

the driving circuit (105) is used for driving the IGBT module (104) to be conducted according to the pot detection signal; and driving the IGBT module (104) to be switched off according to the pot detection stopping signal.

2. The electromagnetic heating circuit (100) of claim 1, wherein the control circuit (106) comprises: the pulse generator PPG comprises a synchronous comparator circuit (1061), a pulse program generator PPG output control circuit (1062), a voltage division circuit (1063) and a micro control unit MCU (1064);

wherein the control end of the MCU (1064) is electrically connected with the target end of the synchronous comparator circuit (1061), the target end of the synchronous comparator circuit (1061) is the same-direction input end or the reverse-direction input end of the synchronous comparator circuit (1061), a first input terminal of the voltage division circuit (1063) is electrically connected with an input terminal of the resonance circuit (103), a second input end of the voltage division circuit (1063) is electrically connected with an output end of the resonance circuit (103), a first output end of the voltage division circuit (1063) is electrically connected with a homodromous input end of the synchronous comparator circuit (1061), a second output end of the voltage division circuit (1063) is electrically connected with an inverting input end of the synchronous comparator circuit (1061), the output end of the synchronous comparator circuit (1061) is electrically connected with the input end of the PPG output control circuit (1062), the output end of the PPG output control circuit (1062) is electrically connected with the input end of the driving circuit (105);

the MCU (1064) is configured to, when receiving the trigger instruction, control a target end of the synchronous comparator circuit (1061) to be in an output state, and change a voltage at the target end of the synchronous comparator circuit (1061), so that a voltage at a same-direction input end of the synchronous comparator circuit (1061) is smaller than a voltage at an opposite-direction input end of the synchronous comparator circuit (1061); when the voltage on the equidirectional input end of the synchronous comparator circuit (1061) is less than the voltage on the reverse input end of the synchronous comparator circuit (1061), controlling the target end of the synchronous comparator circuit (1061) to be in an input state, and stopping changing the voltage on the target end of the synchronous comparator circuit (1061) so that the voltage on the equidirectional input end of the synchronous comparator circuit (1061) is greater than or equal to the voltage on the reverse input end of the synchronous comparator circuit (1061);

the synchronous comparator circuit (1061) is configured to output a first signal to the PPG control output voltage when a voltage at a non-inverting input of the synchronous comparator circuit (1061) is less than a voltage at an inverting input of the synchronous comparator circuit (1061); when the voltage on the equidirectional input end of the synchronous comparator circuit (1061) is greater than or equal to the voltage on the reverse input end of the synchronous comparator circuit (1061), outputting a trigger signal with a level opposite to that of a first signal to the PPG control output circuit;

the PPG output control circuit (1062) is used for sending the pot detection signal to the drive circuit (105) according to the trigger signal; and when the output width of the pot detection signal is greater than or equal to the preset width, outputting the pot detection stopping signal to the driving circuit (105).

3. The electromagnetic heating circuit (100) of claim 2,

the MCU (1064) is configured to, when a target end of the control circuit (106) is a unidirectional input end of the synchronous comparator circuit (1061), control the unidirectional input end of the synchronous comparator circuit (1061) to be in an output state, and pull down a voltage at the unidirectional input end of the synchronous comparator circuit (1061), so that the voltage at the unidirectional input end of the synchronous comparator circuit (1061) is smaller than a voltage at an inverted input end of the synchronous comparator circuit (1061); when the voltage at the equidirectional input end of the synchronous comparator circuit (1061) is less than the voltage at the reverse input end of the synchronous comparator circuit (1061), controlling the equidirectional input end of the synchronous comparator circuit (1061) to be in an input state, and stopping pulling down the voltage at the equidirectional input end of the synchronous comparator circuit (1061), so that the voltage at the equidirectional input end of the synchronous comparator circuit (1061) is greater than or equal to the voltage at the reverse input end of the synchronous comparator circuit (1061).

4. The electromagnetic heating circuit (100) of claim 2,

the MCU (1064) is configured to, when the target end of the control circuit (106) is the inverting input end of the synchronous comparator circuit (1061), control the inverting input end of the synchronous comparator circuit (1061) to be in an output state, and set a voltage at the inverting input end of the synchronous comparator circuit (1061) high, so that a voltage at the same-direction input end of the synchronous comparator circuit (1061) is smaller than a voltage at the inverting input end of the synchronous comparator circuit (1061); when the voltage at the equidirectional input end of the synchronous comparator circuit (1061) is less than the voltage at the reverse input end of the synchronous comparator circuit (1061), controlling the reverse input end of the synchronous comparator circuit (1061) to be in an input state, and stopping increasing the voltage at the reverse input end of the synchronous comparator circuit (1061), so that the voltage at the equidirectional input end of the synchronous comparator circuit (1061) is greater than or equal to the voltage at the reverse input end of the synchronous comparator circuit (1061).

5. The electromagnetic heating circuit (100) according to claim 2, wherein an input terminal of the MCU (1064) is electrically connected to an output terminal of the synchronous comparator circuit (1061) for obtaining a number of flips of the synchronous comparator circuit (1061), wherein the number of flips is used for determining whether a device is to be heated on the electromagnetic heating apparatus (10).

6. The electromagnetic heating circuit (100) according to claim 2, wherein the voltage dividing circuit (1063) comprises: a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor;

the first end of the seventh resistor is electrically connected with the input end of the resonant circuit (103), the first end of the eighth resistor is electrically connected with the output end of the resonant circuit (103), the second end of the seventh resistor is electrically connected with the first end of the ninth resistor, the second end of the eighth resistor is electrically connected with the first end of the tenth resistor, the second end of the ninth resistor and the second end of the tenth resistor are both grounded, the first input end of the control circuit (106) is electrically connected between the second end of the seventh resistor and the first end of the ninth resistor, and the second input end of the control circuit (106) is electrically connected between the second end of the eighth resistor and the first end of the tenth resistor.

7. The electromagnetic heating circuit (100) of claim 1,

the drive circuit (105) comprises: the circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first triode, a second triode, a third triode and a first capacitor;

wherein, the first end of the first resistor, the first end of the third resistor and the drain electrode of the second triode are connected with a preset level, the output end of the control circuit (106) is electrically connected between the second end of the first resistor and the first end of the second resistor, the second end of the first resistor is electrically connected with the first end of the second resistor, the second end of the second resistor is electrically connected with the grid electrode of the first triode, the second end of the third resistor is respectively electrically connected with the drain electrode of the first triode and the grid electrode of the second triode, the first end of the first capacitor is electrically connected between the drain electrode of the first triode and the grid electrode of the third triode, the second end of the first capacitor, the source electrode of the first triode and the drain electrode of the third triode are all grounded, the source electrode of the second triode is electrically connected with the first end of the fourth resistor, the second end of the fourth resistor is electrically connected with the source electrode of the third triode, and the grid electrode of the IGBT module (104) is electrically connected between the second end of the fourth resistor and the source electrode of the third triode;

the electromagnetic heating circuit (100) further comprises: a protection circuit (107); the protection circuit (107) comprises: a fifth resistor, a sixth resistor and a voltage stabilizing diode;

the output end of the driving circuit (105) is respectively and electrically connected with the first end of the voltage stabilizing diode and the first end of the fifth resistor, the second end of the fifth resistor is respectively and electrically connected with the first end of the sixth resistor and the grid electrode of the IGBT module (104), and the second end of the voltage stabilizing diode, the second end of the sixth resistor and the source electrode of the IGBT module (104) are all grounded;

the resonance circuit (103) comprises: a second capacitor and a resonant inductor;

wherein the output end of the filter circuit (102) and the first input end of the control circuit (106) are respectively and electrically connected with the first end of the resonance inductor, the drain electrode of the IGBT module (104) and the second input end of the control circuit (106) are respectively and electrically connected with the second end of the resonance inductor, and the second capacitor is connected with the resonance inductor in parallel;

the filter circuit (102) comprises: a third capacitor;

the first end of the third capacitor is electrically connected between the positive output end of the rectifying circuit (101) and the input end of the resonant circuit (103), and the second end of the third capacitor is grounded.

8. The electromagnetic heating circuit (100) according to any of claims 1-7, wherein the electromagnetic heating circuit (100) further comprises: a surge detection circuit (108);

wherein a first input terminal of the surge detection circuit (108) is electrically connected with a first input terminal of the rectification circuit (101), a second input terminal of the surge detection circuit (108) is electrically connected with a second input terminal of the rectification circuit (101), and an output terminal of the surge detection circuit (108) is electrically connected with a third input terminal of the control circuit (106);

the surge detection circuit (108) is used for sending a surge signal to the control circuit (106) when surge interference in the power supply voltage is detected;

the control circuit (106) is further configured to send the pot detection stop signal to the driving circuit (105) when receiving the surge signal.

9. The electromagnetic heating circuit (100) of claim 8, wherein the surge detection circuit (108) comprises: the first diode, the second diode, the eleventh resistor and the twelfth resistor;

the positive electrode of the first diode is electrically connected with the first input end of the rectifying circuit (101), the positive electrode of the second diode is electrically connected with the second input end of the rectifying circuit (101), the negative electrode of the first diode and the negative electrode of the second diode are respectively electrically connected with the first end of the eleventh resistor, the second end of the eleventh resistor is electrically connected with the first end of the twelfth resistor, the second end of the twelfth resistor is grounded, and the third input end of the control circuit (106) is electrically connected between the second end of the eleventh resistor and the first end of the twelfth resistor.

10. An electromagnetic heating appliance (10), characterized by comprising: the electromagnetic heating circuit (100) of any of claims 1-9.

11. A protection method for an electromagnetic heating circuit (100), characterized by being applied to the electromagnetic heating circuit (100) according to any one of claims 1-9;

the method comprises the following steps:

when a trigger instruction is received, controlling the voltage on the first input end of the control circuit (106) to be smaller than the voltage on the second input end of the control circuit (106), wherein the trigger instruction is used for instructing the control circuit (106) to start pot detection;

when the voltage on the first input end of the control circuit (106) is smaller than the voltage on the second input end of the control circuit (106), controlling the voltage on the first input end of the control circuit (106) to be larger than or equal to the voltage on the second input end of the control circuit (106);

when the voltage on the first input end of the control circuit (106) is controlled to be larger than or equal to the voltage on the second input end of the control circuit (106), a pot detection signal is sent to a driving circuit (105), so that the driving circuit (105) drives an IGBT module (104) to be conducted according to the pot detection signal, and the pot detection signal is used for detecting whether equipment to be heated is arranged on the electromagnetic heating appliance (10);

when the pot detection signal is sent to the driving circuit (105), timing of the output width of the pot detection signal is started, and when the output width of the pot detection signal is larger than or equal to the preset width, a pot detection stopping signal is sent to the driving circuit (105), so that the driving circuit (105) drives the IGBT module (104) to be disconnected according to the pot detection stopping signal, the pot detection stopping signal is used for stopping detecting whether the electromagnetic heating appliance (10) is provided with the equipment to be heated, and the pot detection signal and the pot detection stopping signal are opposite in level.

12. The protection method of an electromagnetic heating circuit (100) according to claim 11, characterized in that the target terminal of the control circuit (106) is a first input terminal of the control circuit (106) or a second input terminal of the control circuit (106);

controlling a voltage on a first input of the control circuit (106) to be less than a voltage on a second input of the control circuit (106), comprising:

controlling a target of the control circuit (106) to be in an output state;

altering a voltage on a target terminal of the control circuit (106) such that a voltage on a first input terminal of the control circuit (106) is less than a voltage on a second input terminal of the control circuit (106);

controlling a voltage at a first input of the control circuit (106) to be equal to or greater than a voltage at a second input of the control circuit (106), comprising:

controlling a target of the control circuit (106) to be in an input state;

ceasing to alter the voltage on the target terminal of the control circuit (106) such that the voltage on the first input terminal of the control circuit (106) is greater than or equal to the voltage on the second input terminal of the control circuit (106).

13. The protection method of an electromagnetic heating circuit (100) according to claim 12, characterized in that, when the target terminal of the control circuit (106) is the first input terminal of the control circuit (106),

the altering a voltage on a target terminal of the control circuit (106) includes:

pulling down a voltage on a target terminal of the control circuit (106);

the ceasing to alter the voltage on the target terminal of the control circuit (106) comprises:

stopping pulling down the voltage on the target terminal of the control circuit (106).

14. The protection method of an electromagnetic heating circuit (100) according to claim 12, characterized in that, when the target terminal of the control circuit (106) is the second input terminal of the control circuit (106),

raising a voltage on a target terminal of the control circuit (106);

stopping raising the voltage on the target terminal of the control circuit (106).

15. The method of protecting an electromagnetic heating circuit (100) of any of claims 11-14, further comprising;

receiving a surge signal sent by a surge detection circuit (108), wherein the surge signal is used for indicating that surge interference exists in the power supply voltage;

sending the pot detection stopping signal to the driving circuit (105).