CN213817209U

CN213817209U - Spontaneous combustion preventing circuit and electromagnetic heating appliance

Info

Publication number: CN213817209U
Application number: CN202022572236.6U
Authority: CN
Inventors: 孙鹏刚; 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: 2020-11-09
Filing date: 2020-11-09
Publication date: 2021-07-27
Anticipated expiration: 2030-11-09

Abstract

The application provides a spontaneous combustion preventing circuit and an electromagnetic heating appliance. The anti-spontaneous combustion circuit includes: the device comprises a rectification filter circuit, a heating main circuit, a driving circuit, a control circuit, a first detection circuit and a protective tube; the protective tube is connected in series with the live wire; the rectification filter circuit is connected with a mains supply line through a protective tube and comprises a filter capacitor connected between a live wire and a zero line; the heating main circuit is respectively connected with the rectifying and filtering circuit and the driving circuit; the control circuit is respectively connected with the driving circuit and the first detection circuit; the first detection circuit is used for detecting the state of the filter capacitor and generating a corresponding state detection signal; the control circuit is used for outputting a continuous conduction signal to the driving circuit according to the state detection signal so as to enable the IGBT in the heating main circuit to be continuously conducted, the IGBT is conducted for a long time and is in overcurrent short circuit, the fuse tube is fused and/or the air switch in the commercial power circuit is disconnected, and therefore safety is improved.

Description

Spontaneous combustion preventing circuit and electromagnetic heating appliance

Technical Field

The embodiment of the application relates to the technical field of circuits, in particular to a spontaneous combustion preventing circuit and an electromagnetic heating appliance.

Background

The electromagnetic heating appliance is a common household appliance for heating, and when the electromagnetic heating appliance works, high-frequency alternating current is utilized to pass through the coil panel so as to enable the bottom of a metal pot placed on the electromagnetic heating appliance to generate eddy current, so that the pot is heated. In order to meet the requirement of Electromagnetic Compatibility (EMC), a large-capacity capacitor is connected between a zero line and a live line of an internal circuit board of the Electromagnetic heating appliance in a crossing mode so as to reduce Electromagnetic interference.

Because the user uses the electromagnetic heating utensil relatively frequently daily, consequently many users are used to do not pull out power plug after having used the electromagnetic heating utensil, and electromagnetic heating utensil internal circuit board is electrified for a long time promptly, and this makes the electric capacity between zero line and the live wire also be in operating condition always, and the frequency along with commercial power alternating current constantly carries out charge and discharge.

The capacitor is easy to damage and lose efficacy when being in a working state for a long time, once the capacitor loses efficacy, the current is increased rapidly, the temperature rises rapidly in a short time, the internal pressure of the capacitor is increased, the capacitor shell is cracked, and the internal polypropylene film is melted and extruded out of the capacitor shell. Because the polypropylene ethylene film is not a flame retardant material, once the temperature is too high, the polypropylene ethylene film is easy to burn, so that the whole electromagnetic heating appliance burns to cause fire, and serious potential safety hazards are caused.

SUMMERY OF THE UTILITY MODEL

The embodiment of the application provides a prevent spontaneous combustion circuit and electromagnetic heating utensil to avoid the device burning, improve the security of electromagnetic heating utensil.

In a first aspect, the present application provides an anti-pyrophoric circuit comprising: the device comprises a rectification filter circuit, a heating main circuit, a driving circuit, a control circuit, a first detection circuit and a protective tube;

the fuse tube is connected in series on a live wire;

the rectification filter circuit is connected with a mains supply line through the protective tube, and comprises a filter capacitor connected between the live wire and the zero line;

the heating main circuit is respectively connected with the rectifying and filtering circuit and the driving circuit;

the control circuit is respectively connected with the drive circuit and the first detection circuit;

the first detection circuit is used for detecting the state of the filter capacitor and generating a corresponding state detection signal;

the control circuit is used for outputting a continuous conduction signal to the drive circuit according to the state detection signal so as to enable the IGBT in the heating main circuit to be continuously conducted until the fuse tube is fused and/or the air switch in the commercial power line is disconnected.

The spontaneous combustion preventing circuit detects the state of a filter capacitor between a live wire and a zero line by adding a detection circuit in the circuit, when the filter capacitor is determined to be damaged, an IGBT in a driving heating main circuit is continuously conducted, the IGBT is conducted for a long time to cause overcurrent short circuit, and the current flowing through a protective tube is overloaded, so that the protective tube is fused and/or an air switch in a mains supply circuit is disconnected, the power supply of the circuit is thoroughly cut off, the conditions of fire hazard and the like caused by temperature rise when the filter capacitor is damaged are avoided, and the safety and the reliability of the circuit are improved.

In one possible implementation, the first detection circuit includes a sensor and a first state detection circuit;

the sensor is used for detecting the state of the filter capacitor;

the first state detection circuit is used for generating a state detection signal according to the state of the filter capacitor.

In one possible implementation, the sensor includes a pressure sensor and/or a temperature sensor.

The spontaneous combustion preventing circuit can timely and accurately judge whether the filter capacitor is damaged or not by adopting the pressure sensor and/or the temperature sensor to detect the state of the filter capacitor, so that the power supply of the circuit can be timely cut off, and the safety is improved.

In a possible implementation manner, when the sensor includes a temperature sensor, the sensor is configured to detect a temperature of the filter capacitor, and the first detection circuit is configured to generate a first temperature signal according to the temperature of the filter capacitor;

the control circuit is used for outputting a continuous conducting signal to the driving circuit when the first temperature signal is larger than a first preset value.

The spontaneous combustion preventing circuit detects the temperature change of the filter capacitor through the temperature sensor, judges whether the filter capacitor is damaged or not, and is simple in circuit structure and easy to achieve.

In a possible implementation manner, when the sensor comprises a pressure sensor, the sensor is used for detecting the pressure of the filter capacitor, and the first detection circuit is used for generating a first pressure signal according to the pressure of the filter capacitor;

the control circuit is used for outputting a continuous conducting signal to the driving circuit when the first pressure signal is larger than a second preset value.

The spontaneous combustion preventing circuit detects the pressure change of the filter capacitor through the pressure sensor, judges whether the filter capacitor is damaged or not, and is simple in circuit structure and easy to achieve.

In one possible implementation, the anti-spontaneous combustion circuit further comprises a second detection circuit;

the second detection circuit is used for detecting the temperature of the heating main circuit and generating a second temperature signal;

the control circuit is used for outputting a continuous conducting signal to the driving circuit when the first temperature signal is greater than the second temperature signal and the difference value is greater than a third preset value.

The spontaneous combustion preventing circuit can prevent misjudgment by comparing the temperature of the filter capacitor with the temperature of the heating main circuit, and further improves the detection accuracy.

In one possible implementation, the first state detection circuit includes a first resistor and a first capacitor;

the first resistor and the first capacitor are connected in series between a power supply and a grounding point; the sensor is connected in parallel with the first capacitance.

In one possible implementation, the first detection circuit includes a switching unit and a second state detection circuit;

the switch unit is arranged around the filter capacitor;

the second state detection circuit is used for generating a state detection signal according to the state of the switch unit.

The spontaneous combustion preventing circuit is simple in structure and does not increase circuit cost, and the switch is arranged around the filter capacitor, so that the deformation of the filter capacitor or surrounding devices can be detected, the deformation of the filter capacitor can be accurately judged through the shape of the switch, and the power supply of the circuit can be timely cut off.

In one possible implementation, the second state detection circuit includes a second resistor and a second capacitor;

the second resistor and the second capacitor are connected in series between a power supply and a grounding point; the switch unit is connected in parallel with the second capacitor.

In a second aspect, the present application provides an electromagnetic heating appliance comprising an anti-spontaneous combustion circuit as described in the first aspect.

The application provides a prevent spontaneous combustion circuit and electromagnetic heating utensil, through increase a detection circuitry in the circuit and detect the state of the filter capacitance between live wire and the zero line, when confirming filter capacitance damages, IGBT in the drive heating main circuit continuously switches on and makes the air switch disconnection among protective tube fusing and/or the commercial power circuit, thereby thoroughly cut off the power supply of circuit, the temperature risees and then causes the condition such as conflagration when avoiding filter capacitance to damage, the security and the reliability of circuit have been improved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive exercise.

FIG. 1 is a schematic circuit diagram of an electromagnetic heating appliance in the prior art;

FIG. 2 is a schematic structural diagram of an anti-self-ignition circuit according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of an anti-self-ignition circuit according to an embodiment of the present disclosure;

FIG. 4 is a schematic structural diagram of an anti-self-ignition circuit according to an embodiment of the present disclosure;

FIG. 5 is a schematic structural diagram of an anti-self-ignition circuit according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of an anti-self-ignition circuit according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of an auto-ignition prevention circuit according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some embodiments of the present application, but not all embodiments. 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 application.

In the description of the present application, it should be construed that the indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings and are only for convenience in describing the present application and for simplicity in description, but do not indicate or imply that the indicated devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present application.

Electromagnetic heating appliances, such as induction cookers, electric cookers, and the like, mainly use the principle of high-frequency electromagnetic induction to heat. When the electromagnetic heating appliance works, high-frequency alternating current is utilized to pass through the coil panel so as to enable the bottom of a pot placed on the electromagnetic heating appliance to generate eddy current, and therefore the pot arranged on the electromagnetic heating appliance is heated. Fig. 1 is a schematic circuit diagram of an electromagnetic heating appliance in the prior art. In the circuit of the electromagnetic heating appliance, commercial power supplies power for the heating main circuit after rectification and filtration, and the control circuit outputs a driving signal to the driving circuit so that the driving circuit drives the on or off of the IGBT in the heating main circuit, thereby controlling the heating main circuit to heat.

As shown in fig. 1, the rectifying and filtering circuit in the circuit includes a filtering capacitor bridged between the zero line and the live line and a rectifying and filtering unit behind the filtering capacitor, and it can be seen that as long as the zero line and the live line are connected with the commercial power, the circuit is in a charged state, and at this time, the filtering capacitor between the zero line and the live line can be continuously charged and discharged along with the frequency of the commercial power alternating current. If the power plug is not unplugged for a long time after the electromagnetic heating appliance is used, the filter capacitor between the zero line and the live line is also in a working state for a long time and is continuously charged and discharged. The capacitor is easy to damage and lose efficacy when being in a working state for a long time, the temperature is increased to further burn, fire is caused, and the capacitor has serious potential safety hazard.

In order to avoid fire caused by damage and failure of a filter capacitor in the electromagnetic heating appliance, the state of the filter capacitor needs to be detected in time, and when the damage of the filter capacitor is detected, the power supply of a circuit of the electromagnetic heating appliance is cut off in time, so that the situation that the temperature of the damaged filter capacitor is continuously increased to cause combustion is avoided. The following describes how the self-ignition preventing circuit provided by the present application detects the state of the filter capacitor and cuts off the power supply to the circuit of the electromagnetic heating appliance, with reference to the following embodiments.

Fig. 2 is a schematic structural diagram of an anti-spontaneous combustion circuit according to an embodiment of the present disclosure. As shown in fig. 2, the anti-self-ignition circuit includes: the circuit comprises a rectifying and filtering circuit 10, a heating main circuit 20, a driving circuit 30, a control circuit 40, a first detection circuit 50 and a protective tube 60.

Wherein the fuse 60 is connected in series to the fire line.

The rectifying and filtering circuit 10 is connected with a mains line through a protective tube 60, and the rectifying and filtering circuit 10 comprises a filtering capacitor C0 connected between a live wire and a zero wire.

The main heating circuit 20 is connected to the rectifying/smoothing circuit 10 and the driving circuit 30, respectively.

The control circuit 40 is connected to the drive circuit 30 and the first detection circuit 50, respectively.

The first detection circuit 50 is configured to detect a state of the filter capacitor C0 and generate a corresponding state detection signal.

The control circuit 40 is configured to output a continuous conduction signal to the driving circuit 30 according to the state detection signal, so as to continuously conduct the IGBT in the heating main circuit 20 until the fuse 60 is blown and/or the air switch in the utility line is turned off.

When the circuit for preventing spontaneous combustion in this embodiment normally works, the rectifying and filtering circuit 10 filters and rectifies the commercial power and provides the filtered and rectified commercial power to the heating main circuit 20, the control circuit 40 outputs a driving signal to the driving circuit 30, and the driving circuit 30 drives the heating main circuit 20 to work and heat. The heating main circuit 20 includes a resonant circuit and an IGBT (not shown in fig. 2), and the IGBT is turned on or off under the control of the driving circuit 30, so as to control the resonant circuit to generate resonance for heating.

When the self-ignition preventing circuit is in a standby state, namely the power supply is switched on but the control circuit 40 does not control the heating main circuit 20 to heat, although the heating main circuit 20 does not work, the filter capacitor C0 in the rectifying and filtering circuit 10 is still in a working state because the filter capacitor C0 is connected between the live line and the zero line in a bridging manner.

Therefore, in the present embodiment, the state of the filter capacitor C0, which may include at least one of temperature, pressure and deformation of the filter capacitor C0, is detected by the first detection circuit 50 and a state detection signal is generated accordingly. The deformation of the filter capacitor C0 can be obtained by directly detecting the filter capacitor C0, or by detecting the deformation of devices around the filter capacitor C0.

The control circuit 40 may determine the current state of the filter capacitor C0 according to the state detection signal of the first detection circuit 50, for example, when one or more of temperature, pressure and deformation is detected to be excessive, it may be determined that the filter capacitor C0 has been damaged. After the control circuit 40 determines that the filter capacitor C0 is damaged, the continuous conduction signal is output to the driving circuit 30, so that the driving circuit 30 controls the IGBT in the heating main circuit 20 to be continuously conducted, and the IGBT is conducted for a long time to cause an overcurrent and a short circuit, thereby overloading the current flowing through the fuse 60.

After the IGBT continues to conduct and the current flowing through the fuse 60 is overloaded, the current overload of the fuse 60 eventually blows the fuse 60, so that the power supply of the self-ignition preventing circuit is cut off.

Alternatively, in another possible situation, a continuous overload of the current of the fuse 60 may result in the air switch in the input power line (mains line) of the self-ignition prevention circuit being opened, so that the supply of the self-ignition prevention circuit is likewise cut off. For example, the rated current of the fuse 60 is 12A, the rated current of the air switch of the mains line in the household of the user is 16A, the margin of the air switch is small, and the air switch may be turned off before the fuse 60 is fused, so that the power supply of the spontaneous combustion preventing circuit is cut off.

Alternatively, in another possible situation, the current of the fuse 60 continues to overload, which may cause the fuse 60 to blow and the air switch in the mains line to open. When the fuse tube 60 is fused and/or the air switch in the mains supply line is disconnected, the filter capacitor C0 loses power supply completely, so that the fault of the filter capacitor C0 is prevented from further expansion, and the extreme conditions such as burning are avoided.

The spontaneous combustion preventing circuit provided by the embodiment detects the state of the filter capacitor between the live wire and the zero line by adding the detection circuit in the circuit of the electromagnetic heating appliance, when the filter capacitor is determined to be damaged, the IGBT is driven to be continuously conducted to break off the air switch in the fuse tube fusing and/or the power supply of the circuit, the temperature is increased when the filter capacitor is prevented from being damaged, and then the fire disaster and other conditions are caused, so that the safety and the reliability of the circuit are improved.

How the first detection circuit 50 detects the state of the filter capacitor C0 in the above embodiment will be further described below.

Fig. 3 is a schematic structural diagram of an auto-ignition prevention circuit according to an embodiment of the present application, and as shown in fig. 3, the first detection circuit 50 includes a sensor 501 and a first state detection circuit 502.

The sensor 501 is used for detecting the state of the filter capacitor C0; the first state detection circuit 502 is configured to generate a state detection signal according to the state of the filter capacitor C0.

Optionally, the sensor 501 comprises a pressure sensor and/or a temperature sensor, i.e. the sensor 501 may be used to detect the temperature and/or pressure of the filter capacitor C0.

When the sensor 501 comprises a temperature sensor, the sensor 501 is used for detecting the temperature of the filter capacitor C0, and the first detection circuit 50 is used for generating a first temperature signal according to the temperature of the filter capacitor C0; the control circuit 40 is configured to output a continuous conducting signal to the driving circuit 30 when the first temperature signal is greater than the first preset value.

When the filter capacitor C0 is damaged and fails, the internal insulation film of the filter capacitor C0 is short-circuited, the current is rapidly increased, and the temperature rapidly rises in a short time, so the first detection circuit 50 can detect the temperature of the filter capacitor C0, so that the control circuit 40 can judge whether the filter capacitor C0 is damaged according to the temperature, and can determine that the filter capacitor C0 is damaged when the first temperature signal is greater than the first preset value, so as to output a continuous conduction signal to the driving circuit 30, so that the driving circuit 30 controls the IGBT in the heating main circuit 20 to be continuously conducted, the IGBT is conducted for a long time to be over-current and short-circuited, and further, the current flowing through the protective tube 60 is overloaded until the protective tube 60 is fused and/or the air switch in the commercial power line is disconnected. The first preset value can be set according to the temperature value of the filter capacitor C0 in normal operation.

Similar to the above, when the sensor 501 comprises a pressure sensor, the sensor 501 is configured to detect the pressure of the filter capacitor C0, and the first detection circuit 50 is configured to generate a first pressure signal according to the pressure of the filter capacitor C0; the control circuit 40 is configured to output a continuous conducting signal to the driving circuit 30 when the first pressure signal is greater than the second preset value.

When the filter capacitor C0 is damaged and fails, the temperature rises rapidly in a short time, and the internal pressure thereof also increases, so that besides the temperature detection, the pressure of the filter capacitor C0 can be detected, so that the control circuit 40 can judge whether the filter capacitor C0 is damaged according to the pressure, and can determine that the filter capacitor C0 is damaged when the first pressure signal is greater than the second preset value, so as to output a continuous conduction signal to the driving circuit 30, so that the driving circuit 30 controls the IGBT in the heating main circuit 20 to be continuously conducted, the IGBT is conducted for a long time to cause an overcurrent and short circuit, and further cause the current flowing through the fuse 60 to be overloaded until the fuse 60 is fused and/or the air switch in the mains supply line is disconnected. The second preset value can be correspondingly set according to the actual pressure value when the filter capacitor C0 normally works, so that misjudgment is prevented.

It should be noted that the sensor 501 may include a temperature sensor and a pressure sensor, that is, the temperature and the pressure of the filter capacitor C0 may be detected at the same time, so that the control circuit 40 may determine whether the filter capacitor C0 is damaged or not according to the temperature and the pressure, for example, the control circuit 40 may determine that the filter capacitor C0 is damaged when the first temperature signal is greater than the first preset value and the first pressure signal is greater than the second preset value, so as to output a continuous on signal to the driving circuit 30, so as to fuse the fuse 60 and/or disconnect an air switch in the utility line. By detecting the temperature and the pressure simultaneously, the accuracy of detection can be improved, and misjudgment is prevented.

Further, on the basis of the above embodiment, when determining whether the filter capacitor C0 is damaged by detecting the temperature of the filter capacitor C0, the temperature of the environment may be detected by another temperature sensor and compared with the temperature of the filter capacitor C0 to prevent misjudgment.

Illustratively, as shown in fig. 4, on the basis of the above embodiment, the self-ignition preventing circuit further includes: a second detection circuit 70;

the second detection circuit 70 is used for detecting the temperature of the heating main circuit 20 and generating a second temperature signal;

the control circuit 40 is configured to output a continuous conducting signal to the driving circuit 30 when the first temperature signal is greater than the second temperature signal and the difference value is greater than a third preset value.

In this embodiment, the second detection circuit 70 detects the temperature of the main heating circuit 20, and the implementation principle of the second detection circuit 70 may be similar to that of the first detection circuit 50, and is not described herein again.

After the control circuit acquires the first temperature signal of the filter capacitor C0 and the second temperature signal of the heating main circuit 20, if the first temperature signal is greater than the second temperature signal, it indicates that the temperature of the filter capacitor C0 exceeds the normal temperature of the circuit, and when the difference between the first temperature signal and the second temperature signal is greater than a third preset value, it is determined that the temperature of the filter capacitor C0 is too high, and it is determined that the filter capacitor is damaged. Thus, the control circuit 40 outputs a keep-alive signal to the drive circuit 30 to blow the fuse 60 and/or to open the air switch in the mains line.

In this embodiment, not only the temperature of the filter capacitor C0 is detected, but also the ambient temperature, for example, the temperature of the main heating circuit 20 is detected, and the temperature of the filter capacitor C0 is compared with the temperature of the main heating circuit 20 for judgment, so that the accuracy of detection can be improved, and erroneous judgment can be prevented.

On the basis of the above-described embodiment, the first state detection circuit 502 in the first detection circuit 50 is further described.

As shown in fig. 5, the first state detection circuit 502 includes a first resistor R1 and a first capacitor C1;

the first resistor R1 and the first capacitor C1 are connected in series between the power supply and the grounding point; the sensor 501 is connected in parallel with a first capacitance C1.

It should be noted that fig. 5 illustrates a case where the auto-ignition prevention circuit further includes a second detection circuit 70, and the second detection circuit 70 is implemented in the same manner as the first detection circuit 50. Further, a resonance circuit and an IGBT included in the heating main circuit 20 are illustrated in fig. 5.

As shown in fig. 5, when the temperature of the filter capacitor C0 detected by the sensor 501 changes, the voltage output by the sensor 501 changes, so that the voltage across the first capacitor C1 changes, that is, the temperature change of the filter capacitor C0 is converted into a change of a voltage signal by the first state detection circuit, so that the control circuit 40 can determine the temperature of the filter capacitor C0 according to the detected voltage, and further determine whether the filter capacitor C0 is damaged.

In addition to the first detection circuit 50 described in the above embodiment determining whether the filter capacitor C0 is damaged by detecting the temperature and/or pressure of the filter capacitor C0, it may be determined whether the filter capacitor C0 is damaged by detecting deformation. Illustratively, as shown in fig. 6, the first detection circuit 50 includes a switching unit 503 and a second state detection circuit 504.

Wherein, the switch unit 503 is disposed around the filter capacitor C0; the second state detection circuit 504 is configured to generate a state detection signal according to the state of the switch unit 503.

When the filter capacitor C0 is damaged and fails, the temperature rises sharply, the internal pressure of the filter capacitor C0 increases, the capacitor shell cracks, namely, the filter capacitor C0 deforms, and peripheral devices deform. In this embodiment, the switch unit 503 is disposed around the filter capacitor C0, and when the filter capacitor C0 is damaged and fails, the deformation of the filter capacitor C0 may change the switch state of the switch unit 503, for example, the contact of the switch unit 503 changes from closed to open or from open to closed, so that the second state detection circuit may generate the state detection signal according to the state of the switch unit 503. The control circuit 40 can determine whether the filter capacitor C0 is damaged according to the state detection signal output by the second state detection circuit 504.

Illustratively, as shown in fig. 7, the switch unit 503 includes a contact switch, and the second state detection circuit 504 includes a second resistor R2 and a second capacitor C2.

The second resistor R2 and the second capacitor C2 are connected in series between the power supply and the grounding point; the switching unit 503 is connected in parallel with the second capacitor C2.

If the filter capacitor C0 deforms to change the state of the contact switch, the voltage across the second capacitor C2 detected by the control circuit 40 changes, so as to determine whether the filter capacitor C0 is damaged according to the voltage change, and when it is determined that the filter capacitor C0 is damaged, a continuous on signal is output to the driving circuit 30, so that the fuse 60 is blown and/or the air switch in the mains line is disconnected.

In this embodiment, through set up the switch around filter capacitor C0, thereby can detect filter capacitor C0 or the deformation of device on every side, can accurately judge filter capacitor C0 through the form of switch and produce deformation, thereby can in time make the air switch disconnection in fuse 60 fusing and/or the commercial power circuit, the power supply of circuit cut-off, filter capacitor C0 has been avoided damaging the burning, the security has been improved, and circuit structure is simple, the circuit cost is not increased.

The embodiment of the present application further provides an electromagnetic heating appliance, which includes the spontaneous combustion preventing circuit in any of the above embodiments, and the implementation principle and technical effect thereof are similar, and are not described herein again.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described embodiments of the apparatus are merely illustrative, and for example, the division of modules is only one logical division, and other divisions may be realized in practice, for example, a plurality of modules may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or modules, and may be in an electrical, mechanical or other form.

Modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

In addition, functional modules in the embodiments of the present application may be integrated into one processing unit, or each module may exist alone physically, or two or more modules are integrated into one unit. The unit formed by the modules can be realized in a hardware form, and can also be realized in a form of hardware and a software functional unit.

Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the embodiments described above may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it should be noted that: the above embodiments are only used for illustrating the technical solutions of the embodiments of the present application, and are not limited thereto; although the embodiments of the present application have been described in detail with reference to the foregoing embodiments, those skilled in the art will understand 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 such modifications or substitutions do not depart from the spirit and scope of the embodiments of the present application.

Claims

1. An anti-auto-ignition circuit, comprising: the device comprises a rectifying and filtering circuit (10), a heating main circuit (20), a driving circuit (30), a control circuit (40), a first detection circuit (50) and a protective tube (60);

the protective tube (60) is connected in series on a fire line;

the rectification filter circuit (10) is connected with a mains supply line through the protective tube (60), and the rectification filter circuit (10) comprises a filter capacitor C0 connected between the live wire and the zero wire;

the heating main circuit (20) is respectively connected with the rectifying and filtering circuit (10) and the driving circuit (30);

the control circuit (40) is respectively connected with the drive circuit (30) and the first detection circuit (50);

the first detection circuit (50) is used for detecting the state of the filter capacitor C0 and generating a corresponding state detection signal;

the control circuit (40) is used for outputting a continuous conduction signal to the driving circuit (30) according to the state detection signal so as to enable the IGBT in the heating main circuit (20) to be continuously conducted until the fuse tube (60) is fused and/or the air switch in the mains supply line is disconnected.

2. The auto-ignition prevention circuit of claim 1, wherein the first detection circuit (50) comprises a sensor (501) and a first state detection circuit (502);

the sensor (501) is used for detecting the state of the filter capacitor C0;

the first state detection circuit (502) is used for generating a state detection signal according to the state of the filter capacitor C0.

3. The auto-ignition prevention circuit of claim 2, wherein the sensor (501) comprises a pressure sensor and/or a temperature sensor.

4. The auto-ignition prevention circuit of claim 3, wherein when the sensor (501) comprises a temperature sensor, the sensor (501) is configured to detect a temperature of the filter capacitor C0, and the first detection circuit (50) is configured to generate a first temperature signal based on the temperature of the filter capacitor C0;

the control circuit (40) is used for outputting a continuous conducting signal to the driving circuit (30) when the first temperature signal is larger than a first preset value.

5. The auto-ignition prevention circuit of claim 3, wherein when the sensor (501) comprises a pressure sensor, the sensor (501) is configured to detect a pressure of the filter capacitor C0, and the first detection circuit (50) is configured to generate a first pressure signal according to the pressure of the filter capacitor C0;

the control circuit (40) is used for outputting a continuous conducting signal to the driving circuit (30) when the first pressure signal is larger than a second preset value.

6. The auto-ignition prevention circuit of claim 4, further comprising: a second detection circuit (70);

the second detection circuit (70) is used for detecting the temperature of the main heating circuit (20) and generating a second temperature signal;

the control circuit (40) is used for outputting a continuous conducting signal to the drive circuit (30) when the first temperature signal is greater than the second temperature signal and the difference value is greater than a third preset value.

7. The auto-ignition prevention circuit of any of claims 2-6 wherein the first state detection circuit (502) comprises a first resistor R1 and a first capacitor C1;

the first resistor R1 and the first capacitor C1 are connected in series between a power supply and a grounding point; the sensor (501) is connected in parallel with the first capacitance C1.

8. The auto-ignition prevention circuit according to claim 1, wherein the first detection circuit (50) comprises a switching unit (503) and a second state detection circuit (504);

the switch unit (503) is arranged around the filter capacitor C0;

the second state detection circuit (504) is used for generating a state detection signal according to the state of the switch unit (503).

9. The auto-ignition prevention circuit of claim 8 wherein the second state detection circuit (504) comprises a second resistor R2 and a second capacitor C2;

the second resistor R2 and the second capacitor C2 are connected in series between a power supply and a grounding point; the switching unit (503) is connected in parallel with the second capacitor C2.

10. An electromagnetic heating appliance comprising the self-ignition preventing circuit as defined in any one of claims 1 to 9.