CN101932148A

CN101932148A - Electromagnetic heating circuit

Info

Publication number: CN101932148A
Application number: CN2009100335146A
Authority: CN
Inventors: 吴永新; 梁正平; 杨作峰
Original assignee: BAOYING HENGTAI ELECTRICAL EQUIPMENT FACTORY
Current assignee: BAOYING HENGTAI ELECTRICAL EQUIPMENT FACTORY
Priority date: 2009-06-23
Filing date: 2009-06-23
Publication date: 2010-12-29

Abstract

The invention relates to an electromagnetic heating circuit, relating to an electromagnetic heating circuit which comprises an anti-interference circuit, a rectifier circuit, an excitation coil, a resonant capacitor and a single chip, wherein a push-pull power circuit is connected between the rectifier circuit and excitation coil, a comparison circuit is connected between the resonant capacitor and the single chip, a power drive circuit is connected between the single chip and the push-pull power circuit; the push-pull power circuit comprises an IGBT I and an IGBT II, the power drive circuit comprises a push circuit I and a push circuit II which are correspondingly connected with the IGBT I and the IGBT II; the comparison circuit comprises a comparator I and a comparator II the output ends of which are respectively connected with the single chip and output interrupt signals to the single chip; and the single chip response interrupts according to received interrupt signals, and turns to implement an interrupt service instruction to control the push circuit I and the push circuit II to drive the IGBT I and the IGBT II to act alternatively. The anti-interference performance of the electromagnetic heating circuit is effectively improved.

Description

A kind of electromagnetic heating circuit

Technical field

The present invention relates to a kind of electromagnetic heating circuit, relate in particular to a kind of microcontroller embedded electromagnetic heating circuit.

Background technology

Heater adopts the directly-heated type heating in a large number in the industrial production, and electric conversion efficiency is about 40%, and electric conversion efficiency is very low.The family expenses electromagnetic oven adopts the heating of electromagnetism indirect-heating, and electric conversion efficiency is up to more than 90%.But existing electromagnetic heating circuit adopts single power tube (IGBT) to drive magnet exciting coil, as shown in Figure 3, has poor anti jamming capability during application, and the frequency of oscillation locking range is little, and defectives such as the fragile IGBT power tube of off resonance frequently break down circuit.

Summary of the invention

The present invention is directed to above problem, provide a kind of and formed self-oscillation by Single-chip Controlling LC oscillating circuit, again by two IGBT power tubes in the alternation of self-oscillation environment, thereby avoid the electromagnetic heating circuit that frequently breaks down.

Technical scheme of the present invention is: comprise anti-jamming circuit, rectification circuit, magnet exciting coil, resonant capacitance, single-chip microcomputer, between described rectification circuit, magnet exciting coil, be connected with the push-pull type power circuit, between described resonant capacitance and single-chip microcomputer, be connected with comparison circuit, between described single-chip microcomputer and push-pull type power circuit, be connected with power driving circuit; Described push-pull type power circuit comprises IGBT one and IGBT two, and described power driving circuit comprises promotion circuit one, promotes circuit two, and promotion circuit one, promotion circuit two correspondence respectively connect IGBT one and IGBT two; Described comparison circuit comprises comparator I, comparator II, the output of comparator I, comparator II connects single-chip microcomputer respectively and to single-chip microcomputer output interrupt signal, single-chip microcomputer promotes circuit one according to the interrupt signal commands for controlling that receives and promote circuit two to drive IGBT one and IGBT two alternating movements.

Described promotion circuit one by high speed photo coupling, be connected the R13 between high speed photo coupling and the single-chip microcomputer, R1 and the R2 that is connected between high speed photo coupling and the IGBT one and constitute; Described promotion circuit two comprises interconnective triode T1, T2, T3 and R9, R10, R11, R3 and R4.

In the described push-pull type power circuit, the A of IGBT one end links to each other with the positive power source terminal of rectification circuit, and the K end links to each other with the A end of IGBT two, and the K end of IGBT two links to each other with the negative power end of rectification circuit; Magnet exciting coil one end links to each other with the K end of IGBT one, the A end of IGBT two, and the other end is connected with resonant capacitance, the K end of another termination IGBT two of resonant capacitance.

Magnet exciting coil, resonant capacitance and two IGBT power tubes have constituted push-pull power output circuit jointly among the present invention.Single-chip microcomputer passes through; Two promotion circuit are controlled two IGBT power tube alternate conduction respectively, make circuit produce vibration.Vibration back to the positive and negative crest voltage sampling rate in resonant capacitance two ends, when positive and negative crest voltage reaches the magnitude of voltage of setting, voltage comparator produces negative saltus step interrupts the single-chip microcomputer response, control two IGBT power tube alternate conduction formation self-oscillations.Self-oscillation does not exist synchronously and the off resonance problem, and antijamming capability effectively improves.Then quit work during 220 volts of brownouts, because circuit self has the amplitude function, output voltage is constant substantially, can effectively protect the IGBT power tube when too high.This oscillating circuit can be at the hundreds of hertz to 30K hertz operate as normal.

Description of drawings

Fig. 1 is a circuit block diagram of the present invention

Fig. 2 is a schematic circuit of the present invention

Fig. 3 is a background technology condition diagram of the present invention

Embodiment

The present invention as shown in Figure 1, 2, comprise anti-jamming circuit, rectification circuit, magnet exciting coil, resonant capacitance, single-chip microcomputer, between described rectification circuit, magnet exciting coil, be connected with the push-pull type power circuit, between described resonant capacitance and single-chip microcomputer, be connected with comparison circuit, between described single-chip microcomputer and push-pull type power circuit, be connected with power driving circuit; Described push-pull type power circuit comprises IGBT one and IGBT two, and described power driving circuit comprises promotion circuit one, promotes circuit two, and promotion circuit one, promotion circuit two correspondence respectively connect IGBT one and IGBT two; Described comparison circuit comprises comparator I, comparator II, the output of comparator I, comparator II connects single-chip microcomputer respectively and to single-chip microcomputer output interrupt signal, single-chip microcomputer promotes circuit one according to the interrupt signal commands for controlling that receives and promote circuit two to drive IGBT one and IGBT two alternating movements.

The function of each circuit is (as shown in Figure 2) among the present invention:

1) anti-jamming circuit (C1, L1) suppresses to disturb to the filtering of 220V alternating current.

2) rectification circuit (D1, D2, D3, D4), filter circuit (L2, C2) convert the 220V alternating current to DC power supply, are just descending DC power supply negative, about 280V on capacitor C 2 two ends obtain.

3) recommending output (Q1, Q2) is the IGBT power tube, and the A end of Q1 links to each other with the positive power source terminal of C2, and the K end links to each other with the A end of Q2, and the K end of Q2 links to each other with the negative power end of C2; Solenoid L3 one terminates at the K end (the A end of Q2) of Q1, and the other end is connected with resonant capacitance C3, and the K end of another termination Q2 of C3 constitutes totem pole.

4) high speed photo coupling U2, R13 and R1, R2 are the promotion circuit of Q1, and triode T1, T2, T3, R9, R10, R11 and R3, R4 are the promotion circuit of Q2.

5) LM393 includes two voltage comparators (A, B), and the end of oppisite phase 2 pin voltages of A are-9V that the in-phase end 5 pin voltages of B are+10V.Sampling resistor R5, R6 series connection back is in parallel with C3, after C3 both end voltage dividing potential drop, send in-phase end 3 pin of voltage comparator A and end of oppisite phase 6 pin of B with the voltage on the R6.

6) in parallel after D5, two 12V voltage-stabiliser tubes of the D6 differential concatenation with R6, the R6 both end voltage is no more than ± the 12.7V scope.

7)+and the 5V power supply links to each other with the output of voltage comparator B and A respectively with R8, D8 through R7, D7, as the output pull-up circuit, output signal voltage is limited between the 0V-5V, make it to be complementary with the input signal of single-chip microcomputer.

8) output signal of voltage comparator A and B send the INT0/P3.2 (7 pin) of single-chip microcomputer U1 and INT1/P3.3 (8 pin) conduct to interrupt input signal, and the control single chip computer response is interrupted, and turns to carry out corresponding interrupt service routine.

Operation principle of the present invention is:

1) the 220V AC power is sent rectification circuit (D1D2D3D4) rectification through protective tube (BX), anti-interference (L1C1) filtering, and filter circuit (L2C2) filtering makes the C2 two ends obtain negative just down DC power supply, and voltage range is between 260～300V.

2) single-chip microcomputer makes Q1 and Q2 alternate conduction by P1.7 and P1.6 control promotion circuit or ends, and as the P1.7 of single-chip microcomputer, when the P1.6 pin is high/low level, Q1, Q2 then end/conducting.

3) two IGBT power tube alternate conduction of Single Chip Microcomputer (SCM) program control make circuit produce vibration.When P1.6 is a high level, when P1.7 was low level, Q2 ended, the Q1 conducting, the C2 power positive end is through the A of Q1, K, L3, C3 is to ground, C3 is charged, make the C3 end press liter, the R6 end presses liter, when the R6 end is pressed greater than 10V, comparator B output low level, make single-chip microcomputer INT1 (P3.3) produce negative transition response interrupt service routine, control P1.7 is a high level, P1.6 is a low level, and Q1 ends, the Q2 conducting, C3 is through L3, the A of Q2, K, to ground, discharge discharge off, L3 is then to the C3 reverse charging, make C3 end drops, R6 hold drops, when R6 end pressure less than-9V, comparator A output low level, make single-chip microcomputer INT0 (P3.2) produce negative transition response interrupt service routine, control P1.6 is a high level, P1.7 is a low level, and Q2 ends, the Q1 conducting ..., so be concatenated to form self-oscillation.

4) Q2 ends, the Q1 conducting, the C2 power positive end arrives ground through A, K, L3, the C3 of Q1, and C3 is charged, make the C3 end press liter, when C3 voltage greater than 10* (R5+R6)/R6 volt, then the R6 end is pressed greater than 10V, comparator B output low level, make single-chip microcomputer INT1 (P3.3) produce negative transition response interrupt service routine, control P1.7 is that high level, P1.6 are low level, and Q1 ends, the Q2 conducting.Circuit self has the amplitude function.

Claims

1. electromagnetic heating circuit, comprise anti-jamming circuit, rectification circuit, magnet exciting coil, resonant capacitance, single-chip microcomputer, it is characterized in that, between described rectification circuit, magnet exciting coil, be connected with the push-pull type power circuit, between described resonant capacitance and single-chip microcomputer, be connected with comparison circuit, between described single-chip microcomputer and push-pull type power circuit, be connected with power driving circuit; Described push-pull type power circuit comprises IGBT one and IGBT two, and described power driving circuit comprises promotion circuit one, promotes circuit two, and promotion circuit one, promotion circuit two correspondence respectively connect IGBT one and IGBT two; Described comparison circuit comprises comparator I, comparator II, the output of comparator I, comparator II connects single-chip microcomputer respectively and exports interrupt signal to single-chip microcomputer, single-chip microcomputer interrupts according to the interrupt signal response that receives, and turns to carry out break in service commands for controlling promotion circuit one and promote circuit two to drive IGBT one and IGBT two alternating movements.

2. a kind of electromagnetic heating circuit according to claim 1 is characterized in that, described promotion circuit one by high speed photo coupling, be connected the R13 between high speed photo coupling and the single-chip microcomputer, R1 and the R2 that is connected between high speed photo coupling and the IGBT one and constitute; Described promotion circuit two comprises interconnective triode T1, T2, T3 and R9, R10, R11, R3 and R4.

3. a kind of electromagnetic heating circuit according to claim 1 and 2, it is characterized in that in the described push-pull type power circuit, the A of IGBT one end links to each other with the positive power source terminal of rectification circuit, the K end links to each other with the A end of IGBT two, and the K end of IGBT two links to each other with the negative power end of rectification circuit; Magnet exciting coil one end links to each other with the K end of IGBT one, the A end of IGBT two, and the other end is connected with resonant capacitance, the K end of another termination IGBT two of resonant capacitance.