CN205846689U - Electromagnetic heating system and protection device thereof - Google Patents
Electromagnetic heating system and protection device thereof Download PDFInfo
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- CN205846689U CN205846689U CN201620620011.4U CN201620620011U CN205846689U CN 205846689 U CN205846689 U CN 205846689U CN 201620620011 U CN201620620011 U CN 201620620011U CN 205846689 U CN205846689 U CN 205846689U
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Abstract
The utility model discloses a kind of electromagnetic heating system and protection device thereof, described device includes: forward voltage surge testing circuit, the output forward voltage surging signal when input voltage electromagnetic heating system being detected is more than the first predeterminated voltage；Current surge testing circuit, the output current surge signal when operating current switching tube being detected is more than the first predetermined current；Switching tube over-voltage detection circuit, the output switch pipe overvoltage signal when collector voltage switching tube being detected is more than the second predeterminated voltage；Trigger circuit and export trigger protection signal according to forward voltage surging signal, current surge signal and switching tube overvoltage signal, to drive switching tube to turn off by drive circuit.This device can not only avoid the impact that system is caused by forward voltage surging signal and current surge signal; and it can be avoided that switching tube punctures because bearing too high back-pressure; and protect signal after triggering, to directly act on the drive circuit of switching tube, thus improve the protection speed of system.
Description
Technical field
This utility model relates to household electrical appliance technical field, particularly to the protection device and of a kind of electromagnetic heating system
Plant the electromagnetic heating system with it.
Background technology
Generally, electromagnetic heating system such as electromagnetic oven operationally, is highly prone to voltage surge letter in electrical network and work system
Number and the interference of current surge signal, owing to the instantaneous interference signal amplitude of surge is big, destructive strong, thus easily damage system
In components and parts, cause electromagnetic oven operational failure, there is the biggest potential safety hazard.
In correlation technique, it is machine-processed that electromagnetic oven is designed with surge protection, but the surge protection mechanism existence one that forward is unidirectional
Fixed drawback: when negative voltage surging signal comes interim, owing to there is the former of capacitor charge and discharge prior to forward voltage surging signal
Cause so that the voltage surge signal of controller detection is pulled low, if the time interval of two voltage surge signals is the shortest, then may be used
Can cannot completely set up triggering surge to interrupt, cause Lou protection, now energy is accumulated on switching tube completely, and switching tube exists wink
Between the risk of over-voltage breakdown.
Utility model content
One of technical problem that this utility model is intended to solve in correlation technique the most to a certain extent.To this end, this reality
It is to propose the protection device of a kind of electromagnetic heating system by a novel purpose, forward voltage surge can not only be avoided to believe
Number and the impact that system is caused of current surge signal, and it can be avoided that switching tube punctures because bearing too high back-pressure, and,
Protection signal directly acts on the drive circuit of switching tube after triggering, thus improves the protection speed of system, and then improves
The capacity of resisting disturbance of system and reliability.
Another purpose of the present utility model is to propose a kind of electromagnetic heating system.
For achieving the above object, on the one hand this utility model proposes the protection device of a kind of electromagnetic heating system, described
Electromagnetic heating system includes resonance circuit, the current rectifying and wave filtering circuit providing energy to described resonance circuit, drives switching tube open-minded
Or the drive circuit turned off, described resonance circuit is formed by heating coil, resonant capacitance and described switching tube, described protection device
Including: forward voltage surge testing circuit, described forward voltage surge testing circuit is detecting described electromagnetic heating system
Input voltage is more than output forward voltage surging signal during the first predeterminated voltage；Current surge testing circuit, described current surge
Testing circuit is output current surge signal when the operating current described switching tube being detected is more than the first predetermined current；Switching tube
Over-voltage detection circuit, described switching tube over-voltage detection circuit is connected with the colelctor electrode of described switching tube described switch detected
The collector voltage of pipe is more than output switch pipe overvoltage signal during the second predeterminated voltage；Triggering circuit, described triggering circuit has
First signal input part, secondary signal input, the 3rd signal input part and trigger output end, described first signal input part with
The outfan of described forward voltage surge testing circuit is connected, described secondary signal input and described current surge testing circuit
Being connected, described 3rd signal input part is connected with described switching tube over-voltage detection circuit, described trigger output end and described driving
Circuit is connected, and described triggering circuit is according to described forward voltage surging signal, described current surge signal and described switching tube mistake
Pressure signal output trigger protection signal, to drive described switching tube to turn off by described drive circuit.
According to the protection device of electromagnetic heating system of the present utility model, forward voltage surge testing circuit is detecting electricity
The input voltage of magnetic heating system is more than output forward voltage surging signal during the first predeterminated voltage, and current surge testing circuit exists
Detect the operating current of switching tube more than output current surge signal during the first predetermined current, switching tube over-voltage detection circuit exists
Detect that the collector voltage of switching tube, more than output switch pipe overvoltage signal during the second predeterminated voltage, triggers circuit according to forward
Voltage surge signal, current surge signal and switching tube overvoltage signal output trigger protection signal, to drive by drive circuit
Switching tube turns off, thus can not only avoid the impact that system causes by forward voltage surging signal and current surge signal, and
And it can be avoided that switching tube punctures because bearing too high back-pressure, and, protection signal directly acts on driving of switching tube after triggering
Galvanic electricity road, thus improve the protection speed of system, and then improve capacity of resisting disturbance and the reliability of system.
Specifically, the input of described current surge testing circuit is connected to the transmitting of described switching tube by the first resistance
Pole is to detect the operating current of described switching tube.
Further, described first resistance is constantan wire.
Further, described current surge testing circuit includes: the second resistance of series connection and the 3rd resistance, described second electricity
One end of resistance is connected with one end of described first resistance, one end phase of the other end of described second resistance and described 3rd resistance
Even, the other end of described 3rd resistance is connected with default power supply, the other end of described second resistance and the one of described 3rd resistance
Having primary nodal point between end, described primary nodal point is connected to the ground by the first electric capacity；First diode, described first diode
Anode be connected with described primary nodal point；First comparator, the negative input end of described first comparator and described first diode
Negative electrode be connected, the positive input terminal of described first comparator and the first reference voltage are connected, the outfan of described first comparator
It is connected with the secondary signal input of described triggering circuit.
Specifically, described current rectifying and wave filtering circuit includes rectifier bridge, Absorption Capacitance, choking-winding and storage capacitor, described whole
The first input end of stream bridge and the second input correspondence connect the two ends of electric main, and described Absorption Capacitance is connected in parallel on described rectification
Between first outfan and second outfan of bridge, the first outfan phase of one end of described choking-winding and described rectifier bridge
Even, the other end of described choking-winding is connected with one end of described storage capacitor, and is connected to resonant capacitance and the heating of parallel connection
Coil, the other end of described storage capacitor is connected with the second outfan of described rectifier bridge.
Further, the described input of forward voltage surge testing circuit is connected with the first outfan of described rectifier bridge
To detect the input voltage of described electromagnetic heating system.
Further, described forward voltage surge testing circuit includes: the 4th to the 6th resistance of series connection, described 4th electricity
One end of resistance is connected with the first outfan of described rectifier bridge, the other end of described 4th resistance and one end of described 5th resistance
Being connected, the other end of described 5th resistance is connected with one end of described 6th resistance, the other end ground connection of described 6th resistance, and
Described 5th resistor coupled in parallel has the second electric capacity, and described 6th resistance and the 7th resistance connected and the 3rd electric capacity are in parallel, and described the
Between the other end and one end of described 6th resistance of five resistance, there is secondary nodal point；Second diode, described second diode
Anode be connected with described secondary nodal point；Second comparator, the positive input terminal of described second comparator and described second diode
Negative electrode be connected, the negative input end of described second comparator and the second reference voltage are connected, the outfan of described second comparator
It is connected with the first signal input part of described triggering circuit.
Specifically, described switching tube over-voltage detection circuit includes: the 8th resistance of series connection and the 9th resistance, described 8th electricity
One end of resistance is connected with the colelctor electrode of described switching tube, the other end of described 8th resistance and one end phase of described 9th resistance
Even, have between the other end ground connection of described 9th resistance, and the other end of described 8th resistance and one end of described 9th resistance
The 3rd node, described 9th resistor coupled in parallel is had to have the 4th electric capacity；3rd comparator, the positive input terminal of described 3rd comparator and institute
Stating the 3rd node to be connected, the negative input end of described 3rd comparator and the 3rd reference voltage are connected, described 3rd comparator defeated
Go out end to be connected with the 3rd signal input part of described triggering circuit.
Specifically, described triggering circuit is three input nor gates.
Further, described three input nor gates include: or door, the described or first input end of door and described forward voltage
Surge testing circuit is connected, and described or door the second input is connected with described current surge testing circuit；Nor gate, described or
The first input end of not gate is connected with described switching tube over-voltage detection circuit, the second input of described nor gate and described or door
Outfan be connected；3rd diode, the described negative electrode of the 3rd diode is connected with the outfan of described nor gate, and the described 3rd
The anode of diode is connected with described drive circuit.
Specifically, described drive circuit includes: a NPN audion, and the colelctor electrode of a described NPN audion is by the
Ten resistance are connected with default power supply, and the base stage of a described NPN audion is connected with the outfan of described triggering circuit, and described
The emitter stage of one NPN audion is connected with the base stage of described switching tube；First PNP triode, sending out of described first PNP triode
Emitter-base bandgap grading is connected with the emitter stage of a described NPN audion, the base stage of described first PNP triode and described NPN tri-pole
The base stage of pipe is connected, and the colelctor electrode of described first PNP triode is connected with the emitter stage of described switching tube afterwards ground connection；2nd NPN
Audion, the colelctor electrode of described 2nd NPN audion respectively with the base stage and the one of the 11st resistance of a described NPN audion
End is connected, and the described 11st resistance other end is connected with described default power supply, the grounded emitter of described 2nd NPN audion；
12nd resistance of series connection and the 13rd resistance, one end of described 12nd resistance and the base stage phase of described 2nd NPN audion
Even, the other end of described 12nd resistance is connected with one end of described 13rd resistance, the other end of described 13rd resistance and
Described default power supply is connected, and has Section four between the other end and one end of described 13rd resistance of described 12nd resistance
Point, described fourth node is connected with controller.
Additionally, this utility model also proposed a kind of electromagnetic heating system, it includes the guarantor of above-mentioned electromagnetic heating system
Protection unit.
Electromagnetic heating system of the present utility model, by the protection device of above-mentioned electromagnetic heating system, can not only keep away
Exempt from forward voltage surging signal and impact that system is caused by current surge signal, and it can be avoided that switching tube is too high because bearing
Back-pressure and puncture, and, protection signal directly acts on the drive circuit of switching tube after triggering, thus improves the protection of system
Speed, and then improve capacity of resisting disturbance and the reliability of system.
Accompanying drawing explanation
Fig. 1 is the structural representation of the protection device of the electromagnetic heating system according to one embodiment of this utility model.
Fig. 2 is the circuit diagram of the protection device of the electromagnetic heating system according to one embodiment of this utility model.
Detailed description of the invention
Of the present utility model embodiment is described below in detail, and the example of described embodiment is shown in the drawings, the most ad initio
Represent same or similar element to same or similar label eventually or there is the element of same or like function.Below by ginseng
It is exemplary for examining the embodiment that accompanying drawing describes, it is intended to be used for explaining this utility model, and it is not intended that to this utility model
Restriction.
Below with reference to the accompanying drawings describe according to this utility model embodiment propose electromagnetic heating system protection device and
There is its electromagnetic heating system.
Fig. 1 is the structural representation of the protection device of the electromagnetic heating system according to one embodiment of this utility model.
In embodiment of the present utility model, as it is shown in figure 1, electromagnetic heating system can include resonance circuit, to resonance
Circuit provides the drive circuit 20 that the current rectifying and wave filtering circuit 10 of energy, driving switching tube Q are switched on or off, and resonance circuit is by heating
Coil L0, resonant capacitance C0 and switching tube Q composition.
As it is shown in figure 1, the protection device of this electromagnetic heating system includes: forward voltage surge testing circuit 30, electric current wave
Gush testing circuit 40, switching tube over-voltage detection circuit 50 and trigger circuit 60.
Wherein, forward voltage surge testing circuit 30 is preset more than first at input voltage electromagnetic heating system being detected
Forward voltage surging signal is exported during voltage.Current surge testing circuit 40 is detecting that the operating current of switching tube Q is more than the
Current surge signal is exported during one predetermined current.Switching tube over-voltage detection circuit 50 is connected with the colelctor electrode of switching tube Q with in inspection
Measure the collector voltage of switching tube Q more than output switch pipe overvoltage signal during the second predeterminated voltage.Trigger circuit 60 and have the
One signal input part IN1, secondary signal input IN2, the 3rd signal input part IN3 and trigger output end OUT, the first signal is defeated
Enter to hold IN1 to be connected with the outfan of forward voltage surge testing circuit 30, secondary signal input IN2 and current surge detection electricity
Road 40 is connected, and the 3rd signal input part IN3 is connected with switching tube over-voltage detection circuit 50, trigger output end OUT and drive circuit
20 are connected, and trigger circuit 60 and export triggering guarantor according to forward voltage surging signal, current surge signal and switching tube overvoltage signal
Protect signal, to drive switching tube Q to turn off by drive circuit 20.First predeterminated voltage, the first predetermined current and second preset electricity
Pressure can be demarcated according to practical situation.
Specifically, in electromagnetic heating system work process, electric main is converted to unidirectional current by current rectifying and wave filtering circuit 10
Electric energy, controller output drive signal such as PPG (Programme Pulse Generator, arteries and veins able to programme is provided to resonance circuit
Rushing generator) signal is to drive circuit 20, to be driven the turn-on and turn-off of switching tube Q by drive circuit 20, by rectifying and wave-filtering
The unidirectional current of circuit 10 output is converted to high-frequency alternating current.Meanwhile, examined by forward voltage surge testing circuit 30, current surge
Slowdown monitoring circuit 40 and the switching tube over-voltage detection circuit 50 detection input voltage of electromagnetic heating system, the work of switching tube Q the most in real time
Make electric current (i.e. peak point current during system work) and the collector voltage (voltage that switching tube Q is born) of switching tube Q.
If the input voltage of electromagnetic heating system is more than the first predeterminated voltage, or the operating current of switching tube Q is more than
First predetermined current, or the collector voltage of switching tube Q is more than the second predeterminated voltage, i.e. input voltage surge, work is occurring
Undergoing mutation as electric current or time switching tube Q severe overvoltage etc. is dangerous, corresponding testing circuit will export corresponding signal to the most tactile
Power Generation Road 60, then, triggering circuit 60 exports trigger protection signal and directly acts on the drive circuit 20 of switching tube Q, so that opening
Close pipe Q to rapidly switch off, thus the impact that system causes by forward voltage surging signal and current surge signal can not only be avoided,
And it can be avoided that switching tube punctures because bearing too high back-pressure, and, protection signal directly acts on switching tube after triggering
Drive circuit, thus improve the protection speed of system, and then improve capacity of resisting disturbance and the reliability of system.
According to an embodiment of the present utility model, as shown in Figure 1 or 2, the input of current surge testing circuit 40
It is connected to the emitter stage of switching tube Q to detect the operating current of switching tube Q by the first resistance R1.Wherein, the first resistance R1 can
Think constantan wire.
Specifically, as in figure 2 it is shown, current surge testing circuit 40 may include that the second resistance R2, the 3rd resistance R3,
One diode D1 and the first comparator U1, wherein, the second resistance R2 and the 3rd resistance R3 series connection, one end of the second resistance R2 and the
One end of one resistance R1 is connected, and the other end of the second resistance R2 and one end of the 3rd resistance R3 are connected, another of the 3rd resistance R3
End is connected with default power supply VCC, has primary nodal point J1 between the other end and one end of the 3rd resistance R3 of the second resistance R2, the
One node J1 is connected with ground GND by the first electric capacity C1.The anode of the first diode D1 is connected with primary nodal point J1.First compares
The negative input end of device U1 and the negative electrode of the first diode D1 are connected, the positive input terminal of the first comparator U1 and the first reference voltage
REF1 is connected, and the outfan of the first comparator U1 is connected with the secondary signal input IN2 triggering circuit 60.
Specifically, as in figure 2 it is shown, the input of current surge testing circuit 40 is connected with the left end of constantan wire, constantan
Silk is connected with default power supply VCC, the second resistance R2 and the 3rd resistance R3 and is carried out dividing potential drop of connecting, and voltage division signal is through the first diode D1
Inputting the negative input end to the first comparator U1, the positive input terminal of the first comparator U1 is adjustable first reference voltage REF1.
When electric current flows through constantan wire, the voltage of constantan wire left end is negative value, and the electric current flow through is the biggest, and negative sense amplitude is the biggest, therefore
Voltage at one node J1 is the lowest, when voltage is less than the first reference voltage REF1, triggers the first comparator U1 upset, the
The output of one comparator U1 is become high level signal from low level signal, i.e. current surge testing circuit 40 exports current surge letter
Number to triggering circuit 60, then, trigger circuit 60 and export trigger protection signal to drive circuit 20, to be driven by drive circuit 20
Dynamic switching tube Q turns off, thus is prevented effectively to change suddenly because of electric current and impacts system.
According to an embodiment of the present utility model, as shown in Figure 1 or 2, current rectifying and wave filtering circuit 10 include rectifier bridge 11,
Absorption Capacitance C5, choking-winding L1 and storage capacitor C6, the first input end of rectifier bridge 11 and the second input correspondence connect to be handed over
The two ends (L and N) of stream civil power, Absorption Capacitance C5 is connected in parallel between the first outfan of rectifier bridge 11 and the second outfan, chokes
One end of coil L1 is connected with the first outfan of rectifier bridge 11, one end phase of the other end of choking-winding L1 and storage capacitor C6
Even, and being connected to the resonant capacitance C0 of parallel connection and heat coil L0, the other end of storage capacitor C6 is defeated with the second of rectifier bridge 11
Go out end to be connected.
Specifically, electric main can first pass through preposition EMC (Electro Magnetic Compatibility, electromagnetism
Compatible) after module, then carry out rectifying and wave-filtering through current rectifying and wave filtering circuit 10 and carry to resonance circuit with output galvanic current
For electric energy, wherein, choking-winding L1 and Absorption Capacitance C5 in current rectifying and wave filtering circuit 10 constitute filter circuit, to rectifier bridge 11
The unidirectional current of the pulsation of output is filtered exporting galvanic current, and storage capacitor C6 provides resonance energy for resonance circuit
Amount, its value can be 5 μ F.
Further, the input of forward voltage surge testing circuit 30 is connected with the first outfan of rectifier bridge 11 with inspection
Survey the input voltage of electromagnetic heating system.
Wherein, as in figure 2 it is shown, forward voltage surge testing circuit 30 may include that the 4th resistance R4, the 5th resistance R5,
6th resistance R6, the second diode D2, the second comparator U2, wherein, the 4th resistance R4, the 5th resistance R5 and the 6th resistance R6 string
Connection.One end of 4th resistance R4 is connected with the first outfan of rectifier bridge 11, the other end of the 4th resistance R4 and the 5th resistance R5
One end be connected, the other end of the 5th resistance R5 and one end of the 6th resistance R6 are connected, the other end ground connection of the 6th resistance R6
GND, and the 5th resistance R5 is parallel with the second electric capacity C2, the 6th resistance R6 and the 7th resistance R7 connected and the 3rd electric capacity C3 also
Connection, has secondary nodal point J2 between the other end and one end of the 6th resistance R6 of the 5th resistance R5.The anode of the second diode D2
It is connected with secondary nodal point J2.The positive input terminal of the second comparator U2 and the negative electrode of the second diode D2 are connected, the second comparator U2
Negative input end and the second reference voltage REF2 be connected, the outfan of the second comparator U2 with triggering circuit 60 the first signal defeated
Enter to hold IN1 to be connected.
Specifically, as in figure 2 it is shown, the input signal of forward voltage surge testing circuit 30 is the rectified bridge of electric main
Half-wave voltage signal after 11 rectifications, this voltage signal carries out dividing potential drop through the 4th resistance R4, the 5th resistance R5 and the 6th resistance R6,
Voltage division signal is through the positive input terminal of the second diode D2 input to the second comparator U2, and the negative input end of the second comparator U2 is can
The the second reference voltage REF2 adjusted.Second electric capacity C2 can be high pressure ceramic disc capacitor, in parallel with the 5th resistance R5, with at voltage wave
Gush the interim action rapidly of signal, thus realize instantaneous short circuit.7th resistance R7 and the 3rd electric capacity C3 is electric with the 6th again after connecting
Resistance R6 is in parallel, to be filtered voltage surge signal, improves the sensitivity of voltage surge signal.Second comparator U2 is permissible
For high-speed comparator, the second comparator U2 carries out the conversion of low and high level according to the size of input voltage, such as when voltage occur
During surge, the voltage at secondary nodal point J2 will be above the second reference voltage REF2, now the second comparator U2 output high level letter
Number, i.e. forward voltage surge testing circuit 30 output voltage surging signal is to triggering circuit 60, then, triggers circuit 60 output and touches
Send out and protect signal to drive circuit 20, to drive switching tube Q to turn off by drive circuit 20, thus be prevented effectively from because of input voltage
System is impacted by surge.
According to an embodiment of the present utility model, as in figure 2 it is shown, switching tube over-voltage detection circuit 50 may include that
Eight resistance R8, the 9th resistance R9 and the 3rd comparator U3, wherein, the 8th resistance R8 and the 9th resistance R9 series connection.8th resistance R8
One end be connected with the colelctor electrode of switching tube Q, the other end of the 8th resistance R8 and one end of the 9th resistance R9 are connected, the 9th resistance
The other end ground connection GND of R9, and between the other end of the 8th resistance R8 and one end of the 9th resistance R9, there is the 3rd node J3, the
Nine resistance R9 are parallel with the 4th electric capacity C4.The positive input terminal of the 3rd comparator U3 and the 3rd node J3 are connected, the 3rd comparator U3
Negative input end and the 3rd reference voltage REF3 be connected, the outfan of the 3rd comparator U3 with triggering circuit 60 the 3rd signal defeated
Enter to hold IN3 to be connected.
Specifically, as in figure 2 it is shown, colelctor electrode that the input signal of switching tube over-voltage detection circuit 50 is switching tube Q
Voltage signal, is also the voltage signal on the right side of resonant capacitance C0.This voltage signal is carried out through the 8th resistance R8 and the 9th resistance R9
Dividing potential drop, voltage division signal is directly inputted into the positive input terminal of the 3rd comparator U3, and the negative input end of the 3rd comparator U3 is scalable
The 3rd reference voltage REF3.When switching tube Q overvoltage is serious, the voltage at the 3rd node J3 will exceed the 3rd reference of setting
Voltage REF3, the 3rd comparator U3 export high level signal, i.e. switching tube over-voltage detection circuit 50 output switch pipe overvoltage signal
To triggering circuit 60, then, trigger circuit 60 and export trigger protection signal to drive circuit 20, to be driven by drive circuit 20
Switching tube Q turns off, thus realizes the protection of switching tube overvoltage interruption, efficiently solves in correlation technique because of negative voltage surging signal
Early than the too small leakage protection caused of the time interval between forward voltage surging signal, and two surging signals, switch tube is entered
Go and second heavily protected.
According to an embodiment of the present utility model, triggering circuit 60 can be three input nor gates.
Specifically, as in figure 2 it is shown, three input nor gates may include that or door OR, nor gate NOR and the 3rd diode D3,
Wherein, or the first input end of door OR is connected with forward voltage surge testing circuit 30, or second input of door OR and electric current
Surge testing circuit 40 is connected, and the first input end of nor gate NOR is connected with switching tube over-voltage detection circuit 50, nor gate NOR
The second input with or the outfan of door OR be connected, the outfan of negative electrode AND OR NOT gate NOR of the 3rd diode D3 is connected, the
The anode of three diode D3 is connected with drive circuit 20.
Specifically, as in figure 2 it is shown, or door OR input respectively with the outfan of forward voltage surge testing circuit 30
Be connected with the outfan of current surge testing circuit 40, when or time the either input signal of door OR is high level signal, or door OR
High level signal will be exported.Nor gate NOR can be open-drain output nor gate, its input respectively with or the outfan of door OR and
The outfan of switching tube over-voltage detection circuit 50 is connected, when the either input signal of nor gate NOR is high level signal or non-
Door NOR is by output low level signal, and directly acts on the drive circuit 20 of switching tube；Being otherwise open-drain output, it exports electricity
Pressure signal is determined by external circuit.It is to say, three input nor gates can be divided into two-stage, the first order is or the input of door OR
For forward voltage surge testing circuit 30 and current surge testing circuit 40, both enjoy same priority；The second level is first
Level outfan and switching tube over-voltage detection circuit 50, make switching tube over-voltage detection circuit 50 enjoy higher priority, not only rise
The leakage protection of forward voltage surging signal, the most also the second effect heavily protected are arrived.
Further, as in figure 2 it is shown, drive circuit 20 may include that a NPN audion NPN1, the first PNP triode
PNP1, the 2nd NPN audion NPN2, the 12nd resistance R12 and the 13rd resistance R13, wherein, a NPN audion NPN1's
Colelctor electrode is connected with default power supply VCC by the tenth resistance R10, the base stage of a NPN audion NPN1 and triggering circuit 60
Outfan is connected, and the emitter stage of a NPN audion NPN1 is connected with the base stage of switching tube Q, sending out of the first PNP triode PNP1
The emitter stage of emitter-base bandgap grading and a NPN audion NPN1 is connected, the base stage of the first PNP triode PNP1 and a NPN audion
The base stage of NPN1 is connected, and the colelctor electrode of the first PNP triode PNP1 is connected with the emitter stage of switching tube Q afterwards ground connection GND, and second
The colelctor electrode of NPN audion NPN2 is connected with the base stage of a NPN audion NPN1 and one end of the 11st resistance R11 respectively,
The 11st resistance R11 other end is connected with default power supply VCC, the grounded emitter GND of the 2nd NPN audion NPN2, and the 12nd
Resistance R12 and the 13rd resistance R13 series connection, the base stage of one end R12 and the 2nd NPN audion NPN2 of the 12nd resistance is connected,
The other end of the 12nd resistance R12 and one end of the 13rd resistance R13 are connected, the other end of the 13rd resistance R13 and default electricity
Source VCC is connected, and has fourth node J4 between the other end and one end of the 13rd resistance R13 of the 12nd resistance R12, Section four
Point J4 is connected with controller.
Specifically, as in figure 2 it is shown, the PPG signal of controller output is after the 2nd NPN audion NPN2 is anti-phase, then warp
The ground level of switching tube Q is acted on after crossing the push-pull circuit of a NPN audion NPN1 and the first PNP triode PNP1 composition.?
The input of push-pull circuit is connected to the outfan of three input nor gates also by the 3rd diode D3.When there is not overvoltage,
The outfan of three input nor gates is open-drain output, and the input of push-pull circuit is that PPG signal function is in the 2nd NPN audion
Signal after NPN2, provides the driving signal of normal work for the switching tube Q in resonance circuit；When there is overvoltage, three inputs
The outfan of nor gate is low level signal, and the input of push-pull circuit is moved to low level by the 3rd diode D3 by moment and believed
Number, now the base signal of switching tube Q is pulled low, and switching tube Q closes, and stops output, thus realizes the guarantor of switch tube
Protect.
It is to say, in embodiment of the present utility model, forward voltage surge testing circuit 30, electric current wave can be passed through
Gush testing circuit 40 and the switching tube over-voltage detection circuit 50 detection input voltage of electromagnetic heating system the most in real time, system work
Time peak point current and the voltage that born of switching tube Q.Input surge voltage, current break wherein occurs when detecting and opens
When closing potential dangerous such as pipe severe overvoltage, if reaching the triggering threshold values of respective comparator, then comparator output high level letter
Number, trigger circuit 60 and export trigger protection signal, and directly act on the drive circuit 20 of switching tube Q, close with quick acting
Switching tube Q, thus realize the protection of switch tube.
The protection device of the electromagnetic heating system according to this utility model embodiment, forward voltage surge testing circuit is in inspection
The input voltage measuring electromagnetic heating system detects more than output forward voltage surging signal during the first predeterminated voltage, current surge
Circuit is output current surge signal when operating current switching tube being detected is more than the first predetermined current, and switching tube overvoltage detects
Circuit is output switch pipe overvoltage signal when collector voltage switching tube being detected is more than the second predeterminated voltage, triggers circuit root
Trigger protection signal is exported, with by driving electricity according to forward voltage surging signal, current surge signal and switching tube overvoltage signal
Road drives switching tube to turn off, thus can not only avoid the shadow that system causes by forward voltage surging signal and current surge signal
Ring, and it can be avoided that switching tube punctures because bearing too high back-pressure, and protect signal to directly act on switching tube after triggering
Drive circuit, thus improve the protection speed of system, and then improve capacity of resisting disturbance and the reliability of system.
Additionally, embodiment of the present utility model also proposed a kind of electromagnetic heating system, it includes above-mentioned Electromagnetic Heating
The protection device of system, wherein, electromagnetic heating system can be electromagnetic oven, electric cooker etc..
The electromagnetic heating system of this utility model embodiment, by the protection device of above-mentioned electromagnetic heating system, not only
It can be avoided that the impact that system is caused by forward voltage surging signal and current surge signal, and it can be avoided that switching tube is because holding
Punctured by too high back-pressure, and protect signal after triggering, to directly act on the drive circuit of switching tube, thus improve system
Protection speed, and then improve capacity of resisting disturbance and the reliability of system.
In description of the present utility model, it is to be understood that term " " center ", " longitudinally ", " laterally ", " length ", " width
Degree ", " thickness ", " on ", D score, "front", "rear", "left", "right", " vertically ", " level ", " top ", " end " " interior ", " outward ", " suitable
Hour hands ", " counterclockwise ", " axially ", " radially ", the orientation of the instruction such as " circumferential " or position relationship be based on orientation shown in the drawings
Or position relationship, be for only for ease of describe this utility model and simplify describe rather than instruction or hint indication device or
Element must have specific orientation, with specific azimuth configuration and operation, therefore it is not intended that to limit of the present utility model
System.Additionally, term " first ", " second " are only used for describing purpose, and it is not intended that instruction or hint relative importance or
The implicit quantity indicating indicated technical characteristic.Thus, define " first ", the feature of " second " can be expressed or implicit
Ground includes at least one this feature.In description of the present utility model, " multiple " are meant that at least two, such as two, three
Individual etc., unless otherwise expressly limited specifically.
In this utility model, unless otherwise clearly defined and limited, term " install ", " being connected ", " connection ", " Gu
Fixed " etc. term should be interpreted broadly, connect for example, it may be fixing, it is also possible to be to removably connect, or integral；Can be
It is mechanically connected, it is also possible to be electrical connection；Can be to be joined directly together, it is also possible to be indirectly connected to by intermediary, can be two
The connection of element internal or the interaction relationship of two elements, unless otherwise clear and definite restriction.Common skill for this area
For art personnel, above-mentioned term concrete meaning in this utility model can be understood as the case may be.
In the description of this specification, reference term " embodiment ", " some embodiments ", " example ", " specifically show
Example " or the description of " some examples " etc. means to combine this embodiment or example describes specific features, structure, material or spy
Point is contained at least one embodiment of the present utility model or example.In this manual, the schematic table to above-mentioned term
State and be necessarily directed to identical embodiment or example.And, the specific features of description, structure, material or feature are permissible
One or more embodiment in office or example combine in an appropriate manner.Additionally, in the case of the most conflicting, this area
Technical staff the feature of the different embodiments described in this specification or example and different embodiment or example can be entered
Row combines and combination.Although above it has been shown and described that embodiment of the present utility model, it is to be understood that above-mentioned enforcement
Example is exemplary, it is impossible to be interpreted as that those of ordinary skill in the art is of the present utility model to restriction of the present utility model
In the range of above-described embodiment can be changed, revise, replace and modification.
Claims (12)
1. the protection device of an electromagnetic heating system, it is characterised in that described electromagnetic heating system includes resonance circuit, to institute
State the current rectifying and wave filtering circuit that resonance circuit provides energy, the drive circuit driving switching tube to be switched on or off, described resonance circuit
Being made up of heating coil, resonant capacitance and described switching tube, described protection device includes:
Forward voltage surge testing circuit, described forward voltage surge testing circuit is detecting the defeated of described electromagnetic heating system
Enter voltage more than output forward voltage surging signal during the first predeterminated voltage；
Current surge testing circuit, described current surge testing circuit is detecting that the operating current of described switching tube is more than first
Current surge signal is exported during predetermined current；
Switching tube over-voltage detection circuit, described switching tube over-voltage detection circuit is connected with the colelctor electrode of described switching tube with in detection
Output switch pipe overvoltage signal when collector voltage to described switching tube is more than the second predeterminated voltage；
Triggering circuit, described triggering circuit has the first signal input part, secondary signal input, the 3rd signal input part and touches
Sending out outfan, described first signal input part is connected with the outfan of described forward voltage surge testing circuit, described second letter
Number input is connected with described current surge testing circuit, described 3rd signal input part and described switching tube over-voltage detection circuit
Being connected, described trigger output end is connected with described drive circuit, and described triggering circuit is according to described forward voltage surging signal, institute
State current surge signal and described switching tube overvoltage signal output trigger protection signal, described to be driven by described drive circuit
Switching tube turns off.
The protection device of electromagnetic heating system the most according to claim 1, it is characterised in that described current surge detection electricity
The input on road is connected to the emitter stage of described switching tube to detect the operating current of described switching tube by the first resistance.
The protection device of electromagnetic heating system the most according to claim 2, it is characterised in that described first resistance is constantan
Silk.
The protection device of electromagnetic heating system the most according to claim 2, it is characterised in that described current surge detection electricity
Road includes:
Second resistance of series connection and the 3rd resistance, one end of described second resistance is connected with one end of described first resistance, described
The other end of the second resistance is connected with one end of described 3rd resistance, and the other end of described 3rd resistance is connected with default power supply,
Having primary nodal point between the other end and one end of described 3rd resistance of described second resistance, described primary nodal point passes through first
Electric capacity is connected to the ground；
First diode, the anode of described first diode is connected with described primary nodal point；
First comparator, the negative input end of described first comparator is connected with the negative electrode of described first diode, described first ratio
The positive input terminal of relatively device and the first reference voltage are connected, and the outfan of described first comparator is believed with the second of described triggering circuit
Number input is connected.
The protection device of electromagnetic heating system the most according to claim 1, it is characterised in that described current rectifying and wave filtering circuit bag
Including rectifier bridge, Absorption Capacitance, choking-winding and storage capacitor, the first input end of described rectifier bridge and the second input correspondence are even
Connecing the two ends of electric main, described Absorption Capacitance is connected in parallel between the first outfan of described rectifier bridge and the second outfan, institute
First outfan of one end and described rectifier bridge of stating choking-winding is connected, the other end of described choking-winding and described energy storage electricity
The one end held is connected, and is connected to resonant capacitance and heating coil, the other end of described storage capacitor and the described rectification of parallel connection
Second outfan of bridge is connected.
The protection device of electromagnetic heating system the most according to claim 5, it is characterised in that described forward voltage surge is examined
The input of slowdown monitoring circuit be connected with the first outfan of described rectifier bridge with detect described electromagnetic heating system input voltage.
The protection device of electromagnetic heating system the most according to claim 6, it is characterised in that described forward voltage surge is examined
Slowdown monitoring circuit includes:
4th to the 6th resistance of series connection, described one end of 4th resistance is connected with the first outfan of described rectifier bridge, described
The other end of the 4th resistance is connected with one end of described 5th resistance, the other end of described 5th resistance and described 6th resistance
One end is connected, the other end ground connection of described 6th resistance, and described 5th resistor coupled in parallel has the second electric capacity, described 6th resistance with
7th resistance of series connection and the 3rd electric capacity are in parallel, have between the other end and one end of described 6th resistance of described 5th resistance
Secondary nodal point；
Second diode, the anode of described second diode is connected with described secondary nodal point；
Second comparator, the positive input terminal of described second comparator is connected with the negative electrode of described second diode, described second ratio
The negative input end of relatively device and the second reference voltage are connected, and the outfan of described second comparator is believed with the first of described triggering circuit
Number input is connected.
The protection device of electromagnetic heating system the most according to claim 1, it is characterised in that described switching tube overvoltage detects
Circuit includes:
8th resistance of series connection and the 9th resistance, described one end of 8th resistance is connected with the colelctor electrode of described switching tube, described
The other end of the 8th resistance is connected with one end of described 9th resistance, the other end ground connection of described 9th resistance, and the described 8th
Having the 3rd node between the other end and one end of described 9th resistance of resistance, described 9th resistor coupled in parallel has the 4th electric capacity；
3rd comparator, the positive input terminal of described 3rd comparator is connected with described 3rd node, bearing of described 3rd comparator
Input and the 3rd reference voltage are connected, the outfan of described 3rd comparator and the 3rd signal input part of described triggering circuit
It is connected.
9. according to the protection device of the electromagnetic heating system according to any one of claim 1-8, it is characterised in that described triggering
Circuit is three input nor gates.
The protection device of electromagnetic heating system the most according to claim 9, it is characterised in that described three input nor gates
Including:
Or door, described or door first input end is connected with described forward voltage surge testing circuit, and the second of described or door is defeated
Enter end to be connected with described current surge testing circuit；
Nor gate, the first input end of described nor gate is connected with described switching tube over-voltage detection circuit, the of described nor gate
Two inputs are connected with described or door outfan；
3rd diode, the described negative electrode of the 3rd diode is connected with the outfan of described nor gate, described 3rd diode
Anode is connected with described drive circuit.
The protection device of 11. electromagnetic heating systems according to claim 10, it is characterised in that described drive circuit bag
Include:
Oneth NPN audion, the colelctor electrode of a described NPN audion is connected with default power supply by the tenth resistance, and described the
The base stage of one NPN audion is connected with the outfan of described triggering circuit, and the emitter stage of a described NPN audion is opened with described
The base stage closing pipe is connected；
First PNP triode, the emitter stage of described first PNP triode is connected with the emitter stage of a described NPN audion, institute
The base stage of the base stage and a described NPN audion of stating the first PNP triode is connected, the colelctor electrode of described first PNP triode
Ground connection after being connected with the emitter stage of described switching tube；
2nd NPN audion, the colelctor electrode of described 2nd NPN audion respectively with the base stage and of a described NPN audion
One end of 11 resistance is connected, and the described 11st resistance other end is connected with described default power supply, described 2nd NPN audion
Grounded emitter；
12nd resistance of series connection and the 13rd resistance, one end of described 12nd resistance and the base of described 2nd NPN audion
The most connected, the other end of described 12nd resistance is connected with one end of described 13rd resistance, another of described 13rd resistance
End is connected with described default power supply, has the 4th between the other end and one end of described 13rd resistance of described 12nd resistance
Node, described fourth node is connected with controller.
12. 1 kinds of electromagnetic heating systems, it is characterised in that include according to the Electromagnetic Heating according to any one of claim 1-11
The protection device of system.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620620011.4U CN205846689U (en) | 2016-06-20 | 2016-06-20 | Electromagnetic heating system and protection device thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201620620011.4U CN205846689U (en) | 2016-06-20 | 2016-06-20 | Electromagnetic heating system and protection device thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205846689U true CN205846689U (en) | 2016-12-28 |
Family
ID=58153989
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201620620011.4U Withdrawn - After Issue CN205846689U (en) | 2016-06-20 | 2016-06-20 | Electromagnetic heating system and protection device thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN205846689U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107196633A (en) * | 2017-06-23 | 2017-09-22 | 广东美的制冷设备有限公司 | Switch controlling device, ac control system and the refrigeration plant of AC load |
| CN107528289A (en) * | 2016-06-20 | 2017-12-29 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and its protection device |
-
2016
- 2016-06-20 CN CN201620620011.4U patent/CN205846689U/en not_active Withdrawn - After Issue
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107528289A (en) * | 2016-06-20 | 2017-12-29 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and its protection device |
| CN107528289B (en) * | 2016-06-20 | 2020-04-03 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and protection device thereof |
| CN107196633A (en) * | 2017-06-23 | 2017-09-22 | 广东美的制冷设备有限公司 | Switch controlling device, ac control system and the refrigeration plant of AC load |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20161228 Effective date of abandoning: 20200403 |