CN204634072U - The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear - Google Patents

The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear Download PDF

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Publication number
CN204634072U
CN204634072U CN201520126523.0U CN201520126523U CN204634072U CN 204634072 U CN204634072 U CN 204634072U CN 201520126523 U CN201520126523 U CN 201520126523U CN 204634072 U CN204634072 U CN 204634072U
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China
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resistance
circuit
diode
output
zero passage
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CN201520126523.0U
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Chinese (zh)
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冯江平
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佛山市顺德区美的电热电器制造有限公司
美的集团股份有限公司
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Priority to CN201520126523.0U priority Critical patent/CN204634072U/en
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Publication of CN204634072U publication Critical patent/CN204634072U/en

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Abstract

The zero passage that the utility model discloses a kind of electromagnetic heating system and electromagnetic heating system breaker in middle pipe opens checkout gear, electromagnetic heating system comprises the drive circuit of resonant circuit and the driving switch pipe be made up of heater coil, resonant capacitance and switching tube, and zero passage is opened checkout gear and comprised: for detecting the current detection circuit of the loop current of resonant circuit; Process to loop current the pulse-detecting circuit exporting the first pulse signal, pulse-detecting circuit is connected with current detection circuit; Main control unit, main control unit is connected with pulse-detecting circuit respectively with drive circuit, main control unit comprises the first counter counted the first pulse signal, wherein, if the count value of the first counter is greater than preset value in Preset Time, main control unit reduces the service time interval of switching tube, to make drive circuit driving switch pipe zero passage open-minded.This device can self-adaptative adjustment service time interval thus, makes switching tube zero passage open-minded, reduces the loss of switching tube.

Description

The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear

Technical field

The utility model relates to technical field of electric appliances, and particularly a kind of zero passage of electromagnetic heating system breaker in middle pipe opens checkout gear and a kind of electromagnetic heating system.

Background technology

Relevant electric cooking pot such as electromagnetic oven adopts single tube IGBT scheme usually, the efficiency of heating surface of single tube electromagnetic oven is high, cost is low, but, the shortcoming that correlation technique exists is, IGBT can only be worth open-minded by rule of thumb, only can be operated in very narrow operation interval, advanced or hysteretic state will be operated in other intervals, closed feedback loop cannot be formed, thus IGBT, coil panel and resonant capacitance equal loss high, dish spacing, cannot make when the factor such as voltage and pan changes and correspondingly judging, the heat that IGBT produces is very large, overtemperature protection need be carried out to IGBT, limit the efficiency of heating surface of electromagnetic oven to a great extent, the efficiency of electromagnetic oven is caused to be difficult to promote.

Utility model content

The purpose of this utility model is intended at least solve one of above-mentioned technological deficiency.

For this reason, an object of the present utility model is that the zero passage proposing a kind of electromagnetic heating system breaker in middle pipe opens checkout gear, and this zero passage opens detection dress can make switching tube zero passage open-minded, reduces the loss of switching tube.

Another object of the present utility model is to propose a kind of electromagnetic heating system.

For achieving the above object, the zero passage of a kind of electromagnetic heating system breaker in middle pipe that the utility model one side embodiment proposes opens checkout gear, it is characterized in that, described electromagnetic heating system comprises the resonant circuit be made up of heater coil, resonant capacitance and switching tube and the drive circuit driving described switching tube, and described zero passage is opened checkout gear and comprised: for detecting the current detection circuit of the loop current of described resonant circuit; Pulse-detecting circuit, described pulse-detecting circuit is connected with described current detection circuit, and described pulse-detecting circuit processes to export the first pulse signal to described loop current; Main control unit, described main control unit is connected with described pulse-detecting circuit respectively with described drive circuit, described main control unit comprises the first counter counted described first pulse signal, wherein, if the count value of described first counter is greater than preset value in Preset Time, described main control unit reduces the service time interval of described switching tube, drives described switching tube zero passage open-minded to make described drive circuit.

Zero passage according to the electromagnetic heating system breaker in middle pipe that the utility model proposes opens checkout gear, the loop current of resonant circuit is detected by current detection circuit, and process to export the first pulse signal to loop current by pulse-detecting circuit, first counter of main control unit can count the first pulse signal, if the count value of the first counter is greater than preset value in Preset Time, then explanation service time interval is excessive, main control unit reduces the service time interval of switching tube, to make switching tube zero passage open-minded.Thus, this zero passage opens checkout gear can according to the service time interval of the loop current self-adaptative adjustment switching tube of resonant circuit, make switching tube can zero passage open-minded, thus reduce the loss of switching tube, reduce the loss of coil panel and resonant capacitance simultaneously, the heat that switching tube is produced reduces, and improves the efficiency of heating surface and the efficiency of electromagnetic heating system.

Further, if the count value of described first counter is less than or equal to described preset value in described Preset Time, the service time interval of described switching tube remains unchanged.

Particularly, described switching tube is IGBT, described current detection circuit comprises current transformer, one end of the armature winding of described current transformer is extremely connected with the C of described IGBT, the other end of the armature winding of described current transformer is connected with resonant capacitance with the heater coil after parallel connection, and the two ends of the secondary winding of described current transformer are as the first output of described current detection circuit and the second output.

Particularly, first resistance of series connection and the second resistance, described one end of first resistance is connected with the negative supply of predeterminated voltage, the other end of described first resistance is connected with one end of described second resistance, have first node between the other end of described first resistance and one end of described second resistance, the other end of described second resistance is connected to the ground; First voltage comparator, the positive input terminal of described first voltage comparator is connected with described first node, the output of described first voltage comparator is connected with described main control unit, the ground end of described first voltage comparator is connected with the negative supply of described predeterminated voltage, and the power end and described first of described first voltage comparator is preset power supply and is connected; 3rd resistance, one end of described 3rd resistance is connected with the output of described first voltage comparator, and the other end and described first of described 3rd resistance is preset power supply and is connected; 4th resistance, described one end of 4th resistance is connected with the first output of described current detection circuit, ground connection after the described other end of the 4th resistance is connected with the second output of described current detection circuit; 5th resistance, one end of described 5th resistance is connected with the first output of described current detection circuit with described one end of 4th resistance respectively; First electric capacity, one end of described first electric capacity is connected with the other end of described 5th resistance, and the other end of described first electric capacity is connected with the second output of described current detection circuit; First diode of series connection and the second diode, the anode of described first diode is connected with the second output of described current detection circuit, the negative electrode of described first diode is connected with the anode of described second diode, between the negative electrode of described first diode and the anode of described second diode, there is Section Point, the negative electrode and described first of described second diode is preset power supply and is connected, and described Section Point is connected with the negative input end of described first voltage comparator with the other end of described 5th resistance respectively.

Particularly, the negative supply of described predeterminated voltage is provided by negative pressure circuit, and wherein, described negative pressure circuit comprises: the 6th resistance and the 7th resistance; PNP triode, the emitter and described first of described PNP triode is preset power supply and is connected, and the base stage of described PNP triode is connected with described main control unit by described 6th resistance; NPN triode, the collector electrode of described NPN triode is connected with the collector electrode of described PNP triode, there is between the collector electrode of described NPN triode and the collector electrode of described PNP triode the 3rd node, the grounded emitter of described NPN triode, the base stage of described NPN triode is connected with described main control unit by described 7th resistance; Second electric capacity, one end of described second electric capacity is connected with described 3rd node; 3rd diode, the anode of described 3rd diode is connected with the other end of described second electric capacity, the minus earth of described 3rd diode; 4th diode, the negative electrode of described 4th diode is connected with the other end of described second electric capacity with the anode of described 3rd diode respectively, the anode of described 4th diode as the output of described negative pressure circuit to provide the negative supply of described predeterminated voltage; 3rd electric capacity, one end of described 3rd electric capacity is connected with the anode of described 4th diode, the other end ground connection of described 3rd electric capacity.

Further, the zero passage of described electromagnetic heating system breaker in middle pipe opens checkout gear, also comprise: for detecting the sync detection circuit of the voltage at described heater coil two ends, described sync detection circuit has the first test side, the second test side and the first output, the second output, described first test side is connected with one end of described heater coil, described second test side is connected with the other end of described heater coil, and the first output, second output of described sync detection circuit are connected respectively to described main control unit.

For achieving the above object, a kind of electromagnetic heating system that the utility model proposes on the other hand, the zero passage comprising described electromagnetic heating system breaker in middle pipe opens checkout gear.

According to the electromagnetic heating system that the utility model proposes, checkout gear is opened by the zero passage of above-mentioned electromagnetic heating system breaker in middle pipe, can the service time interval of self-adaptative adjustment switching tube, make switching tube can zero passage open-minded, avoid open-minded in advance, thus reduce the loss of switching tube, reduce the loss of coil panel and resonant capacitance simultaneously, the heat that switching tube is produced reduces, and can promote the efficiency of heating surface and the efficiency of electromagnetic heating system.

Preferably, described electromagnetic heating system can comprise electromagnetic oven, electromagnetic rice cooker or prevention electromagnetic pressure cooker.

The aspect that the utility model is additional and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present utility model.

Accompanying drawing explanation

The utility model above-mentioned and/or additional aspect and advantage will become obvious and easy understand from the following description of the accompanying drawings of embodiments, wherein:

Fig. 1 is the block diagram opening checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model embodiment

Fig. 2 is the block diagram opening checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model embodiment;

Fig. 3 is the circuit theory diagrams opening checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model specific embodiment;

Fig. 4 is the circuit theory diagrams opening pulse-detecting circuit in checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model specific embodiment;

Fig. 5 is the circuit theory diagrams opening negative pressure circuit in checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model specific embodiment; And

Fig. 6 is the waveform schematic diagram opening checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model specific embodiment.

Reference numeral:

Resonant circuit 20, drive circuit 30, power supply circuits 40, pan 100;

Heater coil 201, resonant capacitance 202 and switching tube 203;

Zero passage opens checkout gear 10, current detection circuit 101, pulse-detecting circuit 102, main control unit 103, sync detection circuit 104 and negative pressure circuit 105;

Current Transmit, first resistance R1, second resistance R2, first voltage comparator U1, 3rd resistance R3, 4th resistance R4, 5th resistance R5, first electric capacity C1, first diode D1, second diode D2, 6th resistance R6, 7th resistance R7, PNP triode Q1, NPN triode Q2, second electric capacity C2, 3rd diode D3, 4th diode D4, 3rd electric capacity C3, first to fourth resistance unit 41-44, 4th electric capacity C4, protection assembly Fx, 5th electric capacity C5, rectifier 401, first inductance L 1 and the 6th electric capacity C6.

Embodiment

Be described below in detail embodiment of the present utility model, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the utility model, and can not being interpreted as restriction of the present utility model.

Disclosing hereafter provides many different embodiments or example is used for realizing different structure of the present utility model.Of the present utility model open in order to simplify, hereinafter the parts of specific examples and setting are described.Certainly, they are only example, and object does not lie in restriction the utility model.In addition, the utility model can in different example repeat reference numerals and/or letter.This repetition is to simplify and clearly object, itself does not indicate the relation between discussed various embodiment and/or setting.In addition, the various specific technique that the utility model provides and the example of material, but those of ordinary skill in the art can recognize the property of can be applicable to of other techniques and/or the use of other materials.In addition, fisrt feature described below second feature it " on " structure can comprise the embodiment that the first and second features are formed as directly contact, also can comprise other feature and be formed in embodiment between the first and second features, such first and second features may not be direct contacts.

In description of the present utility model, it should be noted that, unless otherwise prescribed and limit, term " installation ", " being connected ", " connection " should be interpreted broadly, such as, can be mechanical connection or electrical connection, also can be the connection of two element internals, can be directly be connected, also indirectly can be connected by intermediary, for the ordinary skill in the art, the concrete meaning of above-mentioned term can be understood as the case may be.

The zero passage describing the electromagnetic heating system breaker in middle pipe that the utility model embodiment proposes with reference to the accompanying drawings opens checkout gear and electromagnetic heating system.

Fig. 1 is the block diagram opening checkout gear according to the zero passage of the electromagnetic heating system breaker in middle pipe of the utility model embodiment.

As shown in Figure 1, electromagnetic heating system comprises resonant circuit 20 and drive circuit 30, resonant circuit 20 be made up of heater coil 201, resonant capacitance 202 and switching tube 203 and drive circuit 30 for driving switch pipe.As the example of Fig. 1, heater coil 201 is in parallel with resonant capacitance 202, heater coil 201 after parallel connection is connected with power supply circuits 40 with one end of resonant capacitance 202, heater coil 201 after parallel connection is connected with one end of switching tube 203 with the other end of resonant capacitance 202, the other end ground connection of switching tube 203, the control end of switching tube 203 is connected with drive circuit 30.Certainly, be understandable that, heater coil 201 and resonant capacitance 202 also can be connected in series.

Wherein, resonant circuit 20 can carry out resonance heating to pan 100, particularly, when switching tube conducting, heater coil obtains charging, for the vibration maintained between heater coil and resonant capacitance is prepared, when switching tube is closed, heater coil and resonant capacitance vibrate.Electromagnetic heating system also can comprise the power supply circuits 40 for resonant circuit 20 power supply.It should be noted that, switching tube conducting must be made to maintain vibration when electric discharge closes to an end within cycle of oscillation, firmly opening in situation, no matter switching tube to open in advance or delayed open-minded, the caloric value of switching tube all can very large, loss also can be very large, therefore need driving switch pipe zero passage to open with turn-on consumption minimum.But, because the service time of switching tube generally rule of thumb sets, zero passage cannot be realized exactly open-minded.Therefore, in the utility model embodiment, checkout gear 10 adaptive correction service time is opened by zero passage open-minded to realize switching tube zero passage.

As shown in Figure 1, open checkout gear 10 according to the zero passage of the utility model embodiment to comprise: current detection circuit 101, pulse-detecting circuit 102 and main control unit 103.

Wherein, current detection circuit 101 is for detecting the loop current of resonant circuit 20.Particularly, current detection circuit 101 can be arranged in resonant circuit 20, such as, between the other end that current detection circuit 101 can be connected to the heater coil 201 after parallel connection and resonant capacitance 202 and one end of switching tube 203, the loop current of resonant circuit 20 is the electric current in the loop that heater coil, resonant capacitance and switching tube are formed, more specifically, the loop current of resonant circuit 20 can be the electric current flowing through switching tube.

Pulse-detecting circuit 102 is connected with current detection circuit 101, and pulse-detecting circuit 102 pairs of loop currents process to export the first pulse signal, and that is, pulse-detecting circuit 102 is for being converted to the first pulse signal by loop current.

Main control unit 103 is connected with pulse-detecting circuit 102 respectively with drive circuit 30, main control unit 103 outputs control signals to drive circuit 30 by being connected with drive circuit 30, drive circuit 30 according to control signal output drive signal to switching tube 203 opening and closing with driving switch pipe 203.Main control unit 103 comprises the first counter counted the first pulse signal, wherein, if the count value of the first counter is greater than preset value in Preset Time, main control unit 103 reduces the service time interval T of switching tube, to make drive circuit 30 driving switch pipe 203 zero passage open-minded.That is, if the count value of the first counter is greater than preset value in Preset Time, then illustrate that the service time interval T of switching tube is excessive, namely switching tube is delayed opens conducting after the zero-crossing, now, service time interval T need be reduced to make switching tube zero passage open-minded, thus according to loop current adaptive correction service time interval T.

According to a preferred exemplary of the present utility model, switching tube service time interval initial value can be 1us, Preset Time can be 5ms, and preset value can be 10.Wherein, service time interval initial value, Preset Time and preset value all can set according to actual conditions.

It should be noted that, carry out in the process of vibrating at heater coil 201 and resonant capacitance 202, if electric discharge is near completion, then drive circuit 30 needs driving switch pipe 203 after service time interval T open-minded.Particularly, main control unit 103 can comprise the first timer, according to the voltage at heater coil or resonant capacitance two ends, main control unit 103 can determine whether electric discharge is near completion, when judging that electric discharge is near completion, the first timer can be controlled and start timing, and when the timing time of the first timer reaches the service time interval T of switching tube, main control unit 103 is by the conducting of drive circuit 30 driving switch pipe 203.

In addition, main control unit 103 also can comprise timer, and when timer starts timing, the first counter can start counting simultaneously.Wherein, the timing cycle of the timer in main control unit 103 is set to Preset Time, at the end of timer timing, main control unit 103 preserves the count value of the first counter, and judge whether the count value of the first counter reaches preset value, if the count value of the first counter is greater than preset value, then main control unit 103 reduces the service time interval T of switching tube, and timer re-starts timing, the first counter restarts to count.Be understandable that, when the power that resonant circuit 20 starts to select according to user heats pan 100, timer starts to carry out first time timing, the first counter starts to carry out first time and count.

Also it should be noted that, the first counter counts to the first pulse signal the umber of pulse be in the first pulse signal and counts, and more specifically, the first counter is when a rising edge of the first pulse signal being detected, and the count value of the first counter adds 1.

Further, according to an embodiment of the present utility model, if the count value of the first counter is less than or equal to preset value in Preset Time, the service time interval of switching tube remains unchanged.That is, if the count value of the first counter is less than or equal to preset value, then illustrate that switching tube zero passage is open-minded, main control unit 103 is without the need to adjusting the service time interval of switching tube.

When electromagnetic heating system energising is started working, current detection circuit 101 detects the loop current of resonant circuit 20 in real time, pulse-detecting circuit 102 pairs of loop currents process and export the first pulse signal to main control unit 103, carry out in the process of resonance heating at resonant circuit 20, if drive circuit 30 driving switch pipe is delayed open-minded, a negative current surging signal will be produced in loop current then due to Signal averaging current detection circuit 101 output, now pulse-detecting circuit 102 exports a pulse thereupon, if the umber of pulse in Preset Time in the first pulse signal is greater than preset value, then main control unit 103 reduces service time interval T, thus it is open-minded according to actual conditions adaptive control switching tube zero passage.

Zero passage according to the electromagnetic heating system breaker in middle pipe that the utility model proposes opens checkout gear, the loop current of resonant circuit is detected by current detection circuit, and process to export the first pulse signal to loop current by pulse-detecting circuit, first counter of main control unit can count the first pulse signal, if the count value of the first counter is greater than preset value in Preset Time, then explanation service time interval is excessive, main control unit reduces the service time interval of switching tube, to make switching tube zero passage open-minded.Thus, this zero passage opens checkout gear can according to the service time interval of the loop current self-adaptative adjustment switching tube of resonant circuit, make switching tube can zero passage open-minded, thus reduce the loss of switching tube, reduce the loss of coil panel and resonant capacitance simultaneously, the heat that switching tube is produced reduces, and improves the efficiency of heating surface and the efficiency of electromagnetic heating system.

According to a concrete example of the present utility model, main control unit 103 can be MCU (Micro Control Unit, micro-control unit).

Further, according to an embodiment of the present utility model, as shown in Figure 2, the zero passage of electromagnetic heating system breaker in middle pipe is opened checkout gear 10 and is also comprised: sync detection circuit 104.Sync detection circuit 104 is for detecting the voltage at heater coil 201 two ends, sync detection circuit 104 has the first test side, the second test side and the first output, the second output, first test side is connected with one end of heater coil 201, second test side is connected with the other end of heater coil 201, and the first output, second output of sync detection circuit 104 are connected respectively to main control unit 103.

It should be noted that, first output of sync detection circuit 104 and the exportable synchronizing signal of the second output are to main control unit 103, main control unit 103 can judge whether to need the conducting of control switch pipe according to synchronizing signal, specifically, when the voltage Vb that the second output that the voltage Va that the first output of sync detection circuit 104 exports is greater than sync detection circuit 104 exports, main control unit 103 can control the first timer and start timing, and when the timing time of the first timer reaches service time interval T by the conducting of drive circuit 30 driving switch pipe.

And, in an embodiment of the present utility model, if the count value of the first counter is greater than preset value in Preset Time, then main control unit 103 judges the voltage Vb that the second output whether the voltage Va that the first output of sync detection circuit 104 exports is greater than sync detection circuit 104 exports further, if, then enter interrupt routine, reduce the service time interval of switching tube, driving switch pipe 203 conducting during service time interval like this after the timing time of the first timer reaches adjustment; If not, then continue the voltage of two outputs detecting sync detection circuit 104, and driving switch pipe 203 conducting when the timing time of the first timer reaches current service time interval.

The circuit structure opening checkout gear 10 below in conjunction with the zero passage of Fig. 3-Fig. 6 to the utility model embodiment is described in detail.

According to the embodiment of Fig. 3, switching tube 203 can be IGBT, current detection circuit 101 comprises Current Transmit, one end of the armature winding of Current Transmit is connected with the C pole (collector electrode) of IGBT, the other end of the armature winding of Current Transmit is connected with resonant capacitance 202 with the heater coil 201 after parallel connection, and the two ends of the secondary winding of Current Transmit are as the first output XL1 of current detection circuit 101 and the second output XL2.In addition, E pole (emitter) ground connection of IGBT, the G pole (collector electrode) of IGBT is connected with drive circuit 30.

Like this, in the resonant tank of resonant circuit 20, add Current Transmit, Current Transmit can detect the loop current of resonant circuit 20 in real time, namely flows through the electric current of switching tube 203.

In addition, it should be noted that, when switching tube 203 is IGBT, driving switch pipe zero passage is opened to be and is driven IGBT open-minded immediately when the C pole tension of IGBT is zero.

According to the embodiment of Fig. 4, pulse-detecting circuit 102 comprises the first resistance R1, the second resistance R2, the first voltage comparator U1, the 3rd resistance R3, the 4th resistance R4, the 5th resistance R5, the first electric capacity C1, the first diode D1 and the second diode D2.

Wherein, first resistance R1 and the second resistance R2 connects, one end of first resistance R1 is connected with the negative supply VDD of predeterminated voltage such as-5V power supply, the other end of the first resistance R1 is connected with one end of the second resistance R2, have first node between the other end of the first resistance R1 and one end of the second resistance R2, the other end of the second resistance R2 is connected to the ground; The positive input terminal of the first voltage comparator U1+be connected with first node, the output INT3 of the first voltage comparator U1 is connected with main control unit 103, the ground end of the first voltage comparator U1 and the negative supply VDD of predeterminated voltage i.e.-5V power supply is connected, and the power end and first of the first voltage comparator U1 is preset power supply VCC such as+5V power supply and is connected; One end of 3rd resistance R3 is connected with the output INT3 of the first voltage comparator U1, and the other end and first of the 3rd resistance R3 is preset power supply VCC i.e.+5V power supply and is connected; One end of 4th resistance R4 is connected with the first output XL1 of current detection circuit 101, ground connection after the other end of the 4th resistance R4 is connected with the second output XL2 of current detection circuit 101; One end of 5th resistance R5 is connected with the first output XL1 of current detection circuit 101 with one end of the 4th resistance R4 respectively; One end of first electric capacity C1 is connected with the other end of the 5th resistance R5, and the other end of the first electric capacity C1 is connected with the second output XL2 of current detection circuit 101; First diode D1 and the second diode D2 connects, the anode of the first diode D1 is connected with the second output XL2 of current detection circuit 101, the negative electrode of the first diode D1 is connected with the anode of the second diode D2, between the negative electrode of the first diode D1 and the anode of the second diode D2, there is Section Point, the negative electrode of the second diode D2 and first is preset power supply VCC i.e.+5V power supply and is connected, Section Point respectively with the negative input end of the other end of the 5th resistance R5 and the first voltage comparator U1-be connected.

That is, the first resistance R1 and the second resistance R2 can carry out dividing potential drop to the negative supply VDD of predeterminated voltage, and the first node between the first resistance R1 and the second resistance R2 provides reference voltage for the first voltage comparator U1; 4th resistance R4 is used for loop current signals to be converted to voltage signal; 5th resistance R5 and the first electric capacity C1 forms low-pass filter circuit with the high frequency spurs in filtering loop current.Like this, the loop current that Current Transmit detects exports from the first output XL1 and the second output XL2, afterwards, loop current is through the conversion of the 4th resistance R4, and through the filtering of the 5th resistance R5 and the first electric capacity C1, be delivered to the negative input end of the first voltage comparator U1-, be delivered to negative input end-voltage and positive input terminal+reference voltage compare, when negative input end-voltage be less than reference voltage time, the output INT3 of the first voltage comparator U1 exports high level; When negative input end-voltage be greater than reference voltage time, the output INT3 output low level of the first voltage comparator U1, so, the output INT3 of the first voltage comparator U1 exports the first pulse signal.

Further, the negative supply VDD of predeterminated voltage is provided by negative pressure circuit 105, wherein, as shown in Figure 5, negative pressure circuit 105 comprises: the 6th resistance R6, the 7th resistance R7, PNP triode Q1, NPN triode Q2, the second electric capacity C2, the 3rd diode D3, the 4th diode D4 and the 3rd electric capacity C3.

Wherein, the emitter and first of PNP triode Q1 is preset power supply VCC i.e.+5V and is connected, and the base stage of PNP triode Q1 is connected with main control unit 103 by the 6th resistance R6; NPN triode Q2 collector electrode is connected with the collector electrode of PNP triode Q1, there is between the collector electrode of NPN triode Q2 and the collector electrode of PNP triode Q1 the 3rd node, the grounded emitter of NPN triode Q2, the base stage of NPN triode Q2 is connected with main control unit 103 by the 7th resistance R7; One end of second electric capacity C2 is connected with the 3rd node; The anode of the 3rd diode D3 is connected with the other end of the second electric capacity C2, the minus earth of the 3rd diode D3; The negative electrode of the 4th diode D4 is connected with the other end of the second electric capacity C2 with the anode of the 3rd diode D3 respectively, the anode of the 4th diode D4 as the output out of negative pressure circuit 105 to provide the negative supply of predeterminated voltage; One end of 3rd electric capacity C3 is connected with the anode of the 4th diode D4, the other end ground connection of the 3rd electric capacity C3.

Specifically, one end of 6th resistance R6 is connected with the base stage of PNP triode Q1, the other end of the 6th resistance R6 is held with the PWM of main control unit 103 and is connected, one end of 7th resistance R7 is connected with the base stage of NPN triode Q2, the other end of the 7th resistance R7 is held with the PWM of main control unit 103 and is connected, main control unit 103 exports PWM (Pulse Width Modulation by the 6th resistance R6 and the 7th resistance R7, pulse width modulation) signal is to PNP triode Q1 and NPN triode Q2, and then the output out controlling negative pressure circuit 105 exports negative predeterminated voltage i.e.-5V.

That is, negative pressure circuit 105 can be the predeterminated voltage that pulse-detecting circuit 102 provides negative, and particularly, the output out of negative pressure circuit 105 is connected with the ground end of the first voltage comparator U1 with one end of the first resistance R1 respectively.

Further, according to the embodiment of Fig. 3, sync detection circuit 104 can comprise first to fourth resistance unit 41-44 and the 4th electric capacity C4.Wherein, first resistance unit 41 is connected with the second resistance unit 42, one end of first resistance unit 41 is connected with one end of heater coil 201, the other end of the first resistance unit 41 is connected with one end of the second resistance unit 42, there is the 4th node, the other end ground connection of the second resistance unit 42 between first resistance unit 41 and the second resistance unit 42, 3rd resistance unit 43 is connected with the 4th resistance unit 44, one end of 3rd resistance unit 43 is connected with the other end of heater coil 201, the other end of the 3rd resistance unit 43 is connected with one end of the 4th resistance unit 44, there is between 3rd resistance unit 43 and the 4th resistance unit 44 the 5th node, the other end ground connection of the 4th resistance unit 44, one end of 4th electric capacity C4 is connected with the 4th node, the other end of the 4th electric capacity C4 is connected with the 5th node, 4th node is as the first output of sync detection circuit 104, 5th node is as the second output of sync detection circuit 104.Preferably, first to fourth resistance unit 41-44 all can comprise multiple resistance of series connection.

In addition, according to the embodiment of Fig. 3, power supply circuits 40 comprise protection assembly Fx, the 5th electric capacity C5, rectifier 401, first inductance L 1 and the 6th electric capacity C6, wherein, one end of protection assembly Fx is connected with the live wire L of the alternating current 220VAC of input, the first input end of rectifier 401 is connected with the other end of protection assembly Fx, and the second input of rectifier 401 is connected with the zero line N of the alternating current 220VAC of input, the first output head grounding of rectifier 401; 5th electric capacity C5 is connected in parallel between the first input end of rectifier 401 and the second input; First inductance L 1 is connected with the 6th electric capacity C6, one end of first inductance L 1 is connected with the second output of rectifier 401, the other end of the first inductance L 1 is connected with one end of the 6th electric capacity C6, the other end ground connection of the 6th electric capacity C6, there is between first inductance L 1 and the 6th electric capacity C6 the 6th node, 6th node is connected with resonant circuit 20, is namely connected with one end of resonant capacitance 202 with the heater coil 201 after parallel connection.

As mentioned above, when electromagnetic heating system energising is started working, resonant circuit 20 starts vibration, the C pole of IGBT and the voltage waveform of G pole are as shown in a in Fig. 6, sync detection circuit 104 detects voltage Va and Vb at heater coil 201 two ends in resonant circuit 20, the waveform of synchronous voltage signal Va and Vb that sync detection circuit 104 exports is as shown in the b in Fig. 6, wherein, when the magnitude of voltage Va of the first output of sync detection circuit 104 is greater than the magnitude of voltage Vb of the second output, represent that in current cycle of oscillation, electric discharge closes to an end, IGBT opens to maintain vibration after service time interval T, wherein, need arrange suitable service time interval T is zero open-minded to make the voltage of IGBT in C pole, if the too small meeting of service time interval T makes IGBT open-minded in advance, if interval T crossed conference and made IGBT delayed open-minded service time.

The utility model embodiment can judge IGBT according to the loop current of resonant circuit 20, and whether zero passage is open-minded.As shown in Figure 3, in resonant circuit 20, add Current Transmit, Current Transmit is from the first output XL1 and the second output XL2 output current signal.The waveform of the loop current that Current Transmit exports is as shown in c in Fig. 6, if service time, interval T was excessive, namely IGBT is open-minded after the voltage zero-cross of C pole, signal can be superimposed upon in the discharge cycle of fly-wheel diode in IGBT, thus the current surge signal that formation one is negative, reaction is the current surge signal that first output one is negative on Current Transmit, then exports the current signal slowly risen.

Afterwards, Current Transmit output current signal is through the conversion of the 4th resistance R4, and through the filtering of the 5th resistance R5 and the first electric capacity C1, be delivered to the negative input end of the first voltage comparator U1-, negative input end-voltage and positive input terminal+reference voltage compare, the output INT3 of the first voltage comparator U1 exports the first pulse signal to main control unit 103.When there is current surge signal in the current signal that Current Transmit exports, the output INT3 of the first voltage comparator U1 can export a pulse, as shown in d in Fig. 6.

Like this, main control unit 103 detects the umber of pulse in the first pulse signal in Preset Time, if umber of pulse is greater than preset value, then main control unit 103 reduces service time interval T, opens, realize self adaptation until reach IGBT zero passage.

Thus, this zero passage opens checkout gear can according to the service time interval of the loop current self-adaptative adjustment switching tube of resonant circuit, make switching tube can zero passage open-minded, thus reduce the loss of switching tube, reduce the loss of coil panel and resonant capacitance simultaneously, the heat that switching tube is produced reduces, and improves the efficiency of heating surface and the efficiency of electromagnetic heating system.

Finally, the utility model embodiment also proposed a kind of electromagnetic heating system, and the zero passage comprising above-mentioned electromagnetic heating system breaker in middle pipe opens checkout gear.

According to the electromagnetic heating system that the utility model embodiment proposes, checkout gear is opened by the zero passage of above-mentioned electromagnetic heating system breaker in middle pipe, can the service time interval of self-adaptative adjustment switching tube, make switching tube can zero passage open-minded, thus reduce the loss of switching tube, reduce the loss of coil panel and resonant capacitance, the heat that switching tube is produced reduces, and can promote the efficiency of heating surface and the efficiency of electromagnetic heating system simultaneously.

Preferably, electromagnetic heating system can comprise electromagnetic oven, electromagnetic rice cooker or prevention electromagnetic pressure cooker.

Should be appreciated that each several part of the present utility model can realize with hardware, software, firmware or their combination.In the above-described embodiment, multiple step or method can with to store in memory and the software performed by suitable instruction execution system or firmware realize.Such as, if realized with hardware, the same in another embodiment, can realize by any one in following technology well known in the art or their combination: the discrete logic with the logic gates for realizing logic function to data-signal, there is the application-specific integrated circuit (ASIC) of suitable combinational logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA) etc.

In addition, each functional unit in each embodiment of the utility model can be integrated in a processing module, also can be that the independent physics of unit exists, also can be integrated in a module by two or more unit.Above-mentioned integrated module both can adopt the form of hardware to realize, and the form of software function module also can be adopted to realize.If described integrated module using the form of software function module realize and as independently production marketing or use time, also can be stored in a computer read/write memory medium.

The above-mentioned storage medium mentioned can be read-only memory, disk or CD etc.

In the description of this specification, specific features, structure, material or feature that the description of reference term " embodiment ", " some embodiments ", " example ", " concrete example " or " some examples " etc. means to describe in conjunction with this embodiment or example are contained at least one embodiment of the present utility model or example.In this manual, identical embodiment or example are not necessarily referred to the schematic representation of above-mentioned term.And the specific features of description, structure, material or feature can combine in an appropriate manner in any one or more embodiment or example.

Although illustrate and described embodiment of the present utility model, for the ordinary skill in the art, be appreciated that and can carry out multiple change, amendment, replacement and modification to these embodiments when not departing from principle of the present utility model and spirit, scope of the present utility model is by claims and equivalency thereof.

Claims (8)

1. the zero passage of an electromagnetic heating system breaker in middle pipe opens checkout gear, it is characterized in that, described electromagnetic heating system comprises the resonant circuit be made up of heater coil, resonant capacitance and switching tube and the drive circuit driving described switching tube, and described zero passage is opened checkout gear and comprised:
For detecting the current detection circuit of the loop current of described resonant circuit;
Pulse-detecting circuit, described pulse-detecting circuit is connected with described current detection circuit, and described pulse-detecting circuit processes to export the first pulse signal to described loop current;
Main control unit, described main control unit is connected with described pulse-detecting circuit respectively with described drive circuit, described main control unit comprises the first counter counted described first pulse signal, wherein, if the count value of described first counter is greater than preset value in Preset Time, described main control unit reduces the service time interval of described switching tube, drives described switching tube zero passage open-minded to make described drive circuit.
2. the zero passage of electromagnetic heating system breaker in middle pipe according to claim 1 opens checkout gear, it is characterized in that, if the count value of described first counter is less than or equal to described preset value in described Preset Time, the service time interval of described switching tube remains unchanged.
3. the zero passage of electromagnetic heating system breaker in middle pipe according to claim 1 and 2 opens checkout gear, it is characterized in that, described switching tube is IGBT, described current detection circuit comprises current transformer, one end of the armature winding of described current transformer is extremely connected with the C of described IGBT, the other end of the armature winding of described current transformer is connected with resonant capacitance with the heater coil after parallel connection, and the two ends of the secondary winding of described current transformer are as the first output of described current detection circuit and the second output.
4. the zero passage of electromagnetic heating system breaker in middle pipe according to claim 3 opens checkout gear, and it is characterized in that, described pulse-detecting circuit comprises:
First resistance of series connection and the second resistance, described one end of first resistance is connected with the negative supply of predeterminated voltage, the other end of described first resistance is connected with one end of described second resistance, have first node between the other end of described first resistance and one end of described second resistance, the other end of described second resistance is connected to the ground;
First voltage comparator, the positive input terminal of described first voltage comparator is connected with described first node, the output of described first voltage comparator is connected with described main control unit, the ground end of described first voltage comparator is connected with the negative supply of described predeterminated voltage, and the power end and first of described first voltage comparator is preset power supply and is connected;
3rd resistance, one end of described 3rd resistance is connected with the output of described first voltage comparator, and the other end and described first of described 3rd resistance is preset power supply and is connected;
4th resistance, described one end of 4th resistance is connected with the first output of described current detection circuit, ground connection after the described other end of the 4th resistance is connected with the second output of described current detection circuit;
5th resistance, one end of described 5th resistance is connected with the first output of described current detection circuit with described one end of 4th resistance respectively;
First electric capacity, one end of described first electric capacity is connected with the other end of described 5th resistance, and the other end of described first electric capacity is connected with the second output of described current detection circuit;
First diode of series connection and the second diode, the anode of described first diode is connected with the second output of described current detection circuit, the negative electrode of described first diode is connected with the anode of described second diode, between the negative electrode of described first diode and the anode of described second diode, there is Section Point, the negative electrode and described first of described second diode is preset power supply and is connected, and described Section Point is connected with the negative input end of described first voltage comparator with the other end of described 5th resistance respectively.
5. the zero passage of electromagnetic heating system breaker in middle pipe according to claim 4 opens checkout gear, it is characterized in that, the negative supply of described predeterminated voltage is provided by negative pressure circuit, and wherein, described negative pressure circuit comprises:
6th resistance and the 7th resistance;
PNP triode, the emitter and described first of described PNP triode is preset power supply and is connected, and the base stage of described PNP triode is connected with described main control unit by described 6th resistance;
NPN triode, the collector electrode of described NPN triode is connected with the collector electrode of described PNP triode, there is between the collector electrode of described NPN triode and the collector electrode of described PNP triode the 3rd node, the grounded emitter of described NPN triode, the base stage of described NPN triode is connected with described main control unit by described 7th resistance;
Second electric capacity, one end of described second electric capacity is connected with described 3rd node;
3rd diode, the anode of described 3rd diode is connected with the other end of described second electric capacity, the minus earth of described 3rd diode;
4th diode, the negative electrode of described 4th diode is connected with the other end of described second electric capacity with the anode of described 3rd diode respectively, the anode of described 4th diode as the output of described negative pressure circuit to provide the negative supply of described predeterminated voltage; And
3rd electric capacity, one end of described 3rd electric capacity is connected with the anode of described 4th diode, the other end ground connection of described 3rd electric capacity.
6. the zero passage of electromagnetic heating system breaker in middle pipe according to claim 1 opens checkout gear, it is characterized in that, also comprises:
For detecting the sync detection circuit of the voltage at described heater coil two ends, described sync detection circuit has the first test side, the second test side and the first output, the second output, described first test side is connected with one end of described heater coil, described second test side is connected with the other end of described heater coil, and the first output, second output of described sync detection circuit are connected respectively to described main control unit.
7. an electromagnetic heating system, is characterized in that, the zero passage comprising the electromagnetic heating system breaker in middle pipe according to any one of claim 1-6 opens checkout gear.
8. electromagnetic heating system according to claim 7, is characterized in that, described electromagnetic heating system comprises electromagnetic oven, electromagnetic rice cooker, prevention electromagnetic pressure cooker.
CN201520126523.0U 2015-03-04 2015-03-04 The zero passage of electromagnetic heating system and breaker in middle pipe thereof opens checkout gear CN204634072U (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017088244A1 (en) * 2015-11-27 2017-06-01 佛山市顺德区美的电热电器制造有限公司 Electromagnetic heating device
CN106813271A (en) * 2015-11-27 2017-06-09 佛山市顺德区美的电热电器制造有限公司 A kind of low-power laser heating electromagnetic oven
CN106813276A (en) * 2015-11-27 2017-06-09 佛山市顺德区美的电热电器制造有限公司 A kind of electromagnetic oven

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017088244A1 (en) * 2015-11-27 2017-06-01 佛山市顺德区美的电热电器制造有限公司 Electromagnetic heating device
CN106813271A (en) * 2015-11-27 2017-06-09 佛山市顺德区美的电热电器制造有限公司 A kind of low-power laser heating electromagnetic oven
CN106813276A (en) * 2015-11-27 2017-06-09 佛山市顺德区美的电热电器制造有限公司 A kind of electromagnetic oven
CN106813271B (en) * 2015-11-27 2019-07-30 佛山市顺德区美的电热电器制造有限公司 A kind of low-power laser heating electromagnetic oven
CN106813276B (en) * 2015-11-27 2020-04-10 佛山市顺德区美的电热电器制造有限公司 Electromagnetic oven

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