CN109004620A - A kind of IGBT current foldback circuit and air conditioner - Google Patents
A kind of IGBT current foldback circuit and air conditioner Download PDFInfo
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- CN109004620A CN109004620A CN201811040798.7A CN201811040798A CN109004620A CN 109004620 A CN109004620 A CN 109004620A CN 201811040798 A CN201811040798 A CN 201811040798A CN 109004620 A CN109004620 A CN 109004620A
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- 238000005070 sampling Methods 0.000 claims abstract description 29
- 239000003990 capacitor Substances 0.000 claims description 67
- 238000001514 detection method Methods 0.000 claims description 22
- 238000007689 inspection Methods 0.000 claims description 4
- 230000005611 electricity Effects 0.000 description 12
- 230000002633 protecting effect Effects 0.000 description 6
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- 238000010586 diagram Methods 0.000 description 4
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- 230000003071 parasitic effect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 239000004065 semiconductor Substances 0.000 description 3
- 238000004378 air conditioning Methods 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000005868 electrolysis reaction Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/08—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current
- H02H3/087—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess current for dc applications
Abstract
The present invention provides a kind of IGBT current foldback circuit and air conditioners, a kind of IGBT current foldback circuit, including current sampling unit, protection location, driving unit and control unit, wherein, the current sampling unit emitter with the switching tube respectively, the DC side cathode of rectifier bridge in the circuit of power factor correction, the input terminal of the protection location is connected, the output end of the protection location is divided into two-way, it is connected all the way with the input terminal of described control unit, another way is connected by a conducting wire with the input terminal of the driving unit, the output end of described control unit is connected with the input terminal of the driving unit, the output end of the driving unit is connected with the grid of the switching tube.In this way, the IGBT current foldback circuit can generate hardware protection in circuit of power factor correction overcurrent, the switching tube more in time, is more effectively protected to realize.
Description
Technical field
The present invention relates to air conditioner technical field, in particular to a kind of IGBT current foldback circuit and air conditioner.
Background technique
Convertible frequency air-conditioner generally increases active power factor correction (Power Factor Correction, power factor school
Just) control technology to improve power factor (PF), while adjusting harmonic current, reduces influence of the air-conditioning to power grid.But active function
Rate factor correcting control program is relatively complicated, controls improper generation overcurrent, the overheat of being easy to burn IGBT (In
Sulated Gate Bipolar Transistor, insulated gate bipolar transistor), protection dress is both increased in usual circuit
It sets, to improve the reliability of circuit.The prior art is essentially all by the way of software and hardware combining, and hardware passes through detection IGBT
Conducting electric current trigger single-chip microcontroller when being more than the threshold values of overcurrent setting, then signal is issued by single-chip microcontroller, stop power factor
Correction work, if but scm software setting, control sequential, logic is unreasonable or SCM anti-interference is poor, it is possible that
Guard delay is out of control, and IGBT is caused to burn, so that air-conditioning be caused to fail.
Summary of the invention
In view of this, the present invention is directed to propose a kind of IGBT current foldback circuit, to solve IGBT easily because of pfc circuit overcurrent
And the problem of burning.
In order to achieve the above objectives, the technical scheme of the present invention is realized as follows:
A kind of IGBT current foldback circuit, for carrying out overcurrent protection, packet to the switching tube in circuit of power factor correction
Include current sampling unit, protection location, driving unit and control unit；Wherein,
The current sampling unit respectively with rectifier bridge in the emitter of the switching tube, the circuit of power factor correction
DC side cathode, the protection location input terminal be connected, the current sampling unit is to the circuit of power factor correction
Output electric current sampled, obtain sample rate current, and the sample rate current is delivered to the input terminal of the protection location；
The protection location is used to convert sampled voltage for the sample rate current and compared with reference voltage, one inspection of output
Survey signal；The output end of the protection location is divided into two-way, is connected all the way with the input terminal of described control unit, another way passes through
One conducting wire is connected with the input terminal of the driving unit；
The output end of described control unit is connected with the input terminal of the driving unit, and described control unit is according to the guarantor
The one control signal of detection signal output for protecting unit output controls the driving unit；
The output end of the driving unit is connected with the grid of the switching tube, and the driving unit is used for according to the guarantor
The detection signal of shield unit output and the control signal of described control unit output control the conducting and shutdown of the switching tube.
Further, the protection location includes the first comparison circuit, and first comparison circuit includes first resistor, the
Two resistance, 3rd resistor, the 4th resistance, the 5th resistance, first comparator, the first DC power supply, the first comparator include
First input end and the second input terminal；The first input end of the first comparator is divided into two-way, all the way through the 4th resistance
Ground connection, another way are connected through the second resistance with first DC power supply；Second input terminal of the first comparator point
For two-way, it is connected respectively with the DC side cathode of the rectifier bridge, the current sampling unit through the 3rd resistor all the way, separately
It is connected all the way through the first resistor with first DC power supply；The output end of the first comparator respectively with the control
The input terminal of unit, the input terminal of the driving unit, one end of the 5th resistance are connected；The other end of 5th resistance
It is connected with power supply.
Further, the protection location further includes latching circuit, to prevent the output of the first comparator is secondary from turning over
Turn, the input terminal of the latching circuit is connected with the output end of the first comparator, the output end of the latching circuit and institute
The first input end for stating first comparator is connected, and the latching circuit is one-way conduction circuit.
Further, the protection location further includes start-up circuit, to release locking of the latching circuit to circuit, institute
The input terminal for stating start-up circuit is connected with the output end of the first comparator, the output end of the start-up circuit and the control
The signal output of unit is connected.
Further, the latching circuit includes first diode, and the cathode of the first diode and described first compares
First input end compared with device is connected, and anode is connected with the output end of the first comparator.
Further, the start-up circuit includes the second diode, the anode of second diode and first ratio
Output end compared with device is connected, and cathode is connected with the signal output of described control unit.
Further, the protection location further includes the second comparison circuit, and second comparison circuit compares including second
Device, the 6th resistance, the 7th resistance, the 8th resistance, the 9th resistance, the second DC power supply, second comparator include first defeated
Enter end and the second input terminal；Second input terminal of second comparator is connected with the output end of the first comparator, described
The first input end of second comparator is divided into two-way, all the way through the 7th resistance eutral grounding, another way through the 6th resistance with
Second DC power supply is connected；The output end of second comparator is divided into two-way, all the way through the 8th resistance and power supply
Power supply is connected, and another way is connected with one end of the 9th resistance；The other end of 9th resistance is single with the control respectively
The input terminal of member, the input terminal of the driving unit are connected.
Further, the protection location further includes first capacitor, the second capacitor, third capacitor, the 4th capacitor, the 5th electricity
Hold, the first capacitor, second capacitor, the third capacitor, the 4th capacitor, the 5th capacitor one end connect
Ground, the other end of the first capacitor are connected with the second output terminal of the first comparator, the other end of second capacitor
It is connected with the first input end of the first comparator, the other end of the third capacitor and the output end of the first comparator
Be connected, the other end of the 4th capacitor is connected with the first input end of second comparator, the 5th capacitor it is another
End is connected with the 9th resistance.
Further, the current sampling circuit includes sampling resistor, described sampling resistor one end respectively with the rectification
Bridge DC side cathode, the 3rd resistor are connected, and the other end is connected and is grounded with the emitter of the switching tube.
Compared with the existing technology, IGBT current foldback circuit of the present invention has the advantage that
In IGBT current foldback circuit of the present invention, the output end of protection location is divided into two-way, all the way with the control
The input terminal of unit processed is connected, and another way is connected by a conducting wire with the input terminal of the driving unit, in PFC
When circuit overcurrent, IGBT current foldback circuit can generate hardware protection first, and the hardware protection response time rings than software protection
It is short between seasonable, the switching tube more in time, is more effectively protected to realize, so that switching tube is not because of PFC electricity
It passes by stream and damages, realize the overcurrent protection of switching tube, improve the stability of circuit, reliability is higher.
Another object of the present invention is to propose a kind of air conditioner, to solve in existing air conditioner IGBT easily because of pfc circuit
Overcurrent and the problem of burn.
In order to achieve the above objectives, the technical scheme of the present invention is realized as follows:
A kind of air conditioner, including above-mentioned IGBT current foldback circuit.
Possessed advantage is identical compared with the existing technology with above-mentioned IGBT current foldback circuit for the air conditioner, herein not
It repeats again.
Detailed description of the invention
The attached drawing for constituting a part of the invention is used to provide further understanding of the present invention, schematic reality of the invention
It applies example and its explanation is used to explain the present invention, do not constitute improper limitations of the present invention.In the accompanying drawings:
Fig. 1 is the schematic diagram of IGBT current foldback circuit described in the embodiment of the present invention；
Fig. 2 is the circuit diagram of circuit of power factor correction, sampling unit and protection location described in the embodiment of the present invention；
Fig. 3 is the circuit diagram of driving unit described in the embodiment of the present invention.
Description of symbols:
10- circuit of power factor correction, 20- current sampling unit, 30- protection location, the first comparison circuit of 301-, 302-
Latching circuit, 303- start-up circuit, the second comparison circuit of 304-, 40- driving unit, 401- driving chip, 50- control unit,
IGBT- switching tube, AC- AC power source, BG1- rectifier bridge, L- inductance, C1- first capacitor, the second capacitor of C2-, C3- third electricity
Hold, the 4th capacitor of C4-, the 5th capacitor of C5-, D1- first diode, the second diode of D2-, D3- third diode, D4- the 4th
Diode, E1, E2- electrolytic capacitor, the first DC power supply of VCC-, the second DC power supply of VD-, R1- first resistor, the second electricity of R2-
Resistance, R3- 3rd resistor, the 4th resistance of R4-, the 5th resistance of R5-, the 6th resistance of R6-, the 7th resistance of R7-, the 8th resistance of R8-,
The 9th resistance of R9-, the tenth resistance of R10-, R11- eleventh resistor, R12- twelfth resistor, R13- thirteenth resistor, R14-
14 resistance, the 15th resistance of R15-, R61- sampling resistor, IC1A- first comparator, the second comparator of IC1B-, CLR- signal
Delivery outlet, ZD1- zener diode.
Specific embodiment
It should be noted that in the absence of conflict, the feature in embodiment and embodiment in the present invention can phase
Mutually combination.
The present invention will be described in detail below with reference to the accompanying drawings and embodiments.
Embodiment 1
As shown in Figure 1, for the schematic diagram of IGBT current foldback circuit in the present embodiment；Wherein, the IGBT overcurrent protection
Circuit includes current sampling unit 20, protection location 30, driving unit 40 and control unit 50.
As shown in connection with fig. 2, current sampling unit 20 respectively with the emitter of switching tube IGBT, circuit of power factor correction 10
The DC side cathode of middle rectifier bridge BG1, the input terminal of protection location 30 are connected, and current sampling unit 20 is to PFC electricity
The output electric current on road 10 is sampled, and sample rate current is obtained, and the sample rate current is delivered to the input terminal of protection location 30.
Protection location 30 is used to convert sampled voltage for the sample rate current and compared with reference voltage, one detection of output
Signal；The output end of protection location 30 is divided into two-way, and PWM_EN is connected with the input terminal of control unit 50 all the way, another way IPM_
FO is connected by a conducting wire with the input terminal of driving unit 40.
The output end PFC_PWM of control unit 50 is connected with the input terminal of driving unit 40, and control unit 50 is according to protection
The one control signal of detection signal output that unit 30 exports controls driving unit 40.
The output end IGBT_Driver of driving unit 40 is connected with the grid of switching tube IGBT, and driving unit 40 is used for root
According to protection location 30 export detection signal and control unit 50 export control Signal-controlled switch pipe IGBT conducting with
Shutdown.
If control abnormal signal or power grid surge, voltage in circuit of power factor correction 10 are too strong to cause detection signal
It is abnormal, it, can cutting output in time after driving unit 40 receives the detection signal that protection location 30 is directly transmitted by conducting wire
The hardware protection of switch tube I GBT is realized with on-off switching tube I GBT to the driving signal of switching tube I GBT grid；
Moreover, after control unit 50 receives the detection signal that protection location 30 transmits, after carrying out signal processing to the detection signal, to
The output control signal of driving unit 40, stops grid output drive signal to switching tube I GBT to control driving unit 40, real
The software protection of switch tube I GBT is showed.
In this way, the output end due to protection location 30 is connected directly by the input terminal of a conducting wire and driving unit 40,
When 10 overcurrent of circuit of power factor correction, IGBT current foldback circuit generates hardware protection first, and the hardware protection response time
It is shorter than the software protection response time, to realize that switch tube IGBT is protected more in time, more effectively, so that switching tube IGBT is not
It is damaged due to 10 overcurrent of circuit of power factor correction, improves the stability of circuit, reliability is higher.
Embodiment 2
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, this
Circuit of power factor correction 10 includes AC power source AC, rectifier bridge BG1, inductance L, switching tube IGBT, the four or two pole in embodiment
Pipe D4, electrolytic capacitor E1, electrolytic capacitor E2.The first ac input end of rectifier bridge BG1 is connected to the zero line side of AC power source AC
The second ac input end of ACN, rectifier bridge BG1 are connected to the phase line end ACL of AC power source AC.The DC side of rectifier bridge BG1 is just
Pole is connected to one end of inductance L, and the other end of inductance L is divided into two-way, is connected to the collector of switching tube IGBT, another way all the way
It is connected to the anode of the 4th diode D4.The cathode of 4th diode D4 is the output end of circuit of power factor correction 10, electrolysis
Capacitor E1, electrolytic capacitor E2 are both connected between the cathode and ground of the 4th diode D4.
Embodiment 3
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, protect
Protecting unit 30 includes the first comparison circuit 301, and the first comparison circuit 301 includes first resistor R1, second resistance R2,3rd resistor
R3, the 4th resistance R4, the 5th resistance R5, first comparator IC1A, the first DC power supply VCC.
First comparator IC1A includes first input end and the second input terminal, the first input end point of first comparator IC1A
It for two-way, is grounded all the way through the 4th resistance R4, another way is connected through second resistance R2 with the first DC power supply VCC.First compares
The second input terminal of device IC1A is divided into two-way, adopts respectively with DC side cathode, the electric current of rectifier bridge BG1 through 3rd resistor R3 all the way
Sample unit 20 is connected, and another way is connected through first resistor R1 with the first DC power supply VCC.The output end of first comparator IC1A point
It is not connected with one end of the input terminal of control unit 50, the input terminal of driving unit 40, the 5th resistance R5.5th resistance R5's is another
One end is connected with power supply.
Preferred current sampling unit 20 is sampling resistor R61 in the present embodiment, and sampling resistor R61 resistance value is milliampere grade, pressure
Drop is negligible.The one end sampling resistor R61 is connected with rectifier bridge BG1 DC side cathode, 3rd resistor R3 respectively, the other end and switch
The emitter of pipe IGBT is connected and is grounded.It is preferred that the first input end of first comparator IC1A is its non-inverting input terminal, second is defeated
Entering end is its inverting input terminal.First resistor R1, second resistance R2,3rd resistor R3, the 4th resistance R4 are as divider resistance, electricity
Hinder pull-up resistor of the R5 as first comparator IC1A output end.In the present embodiment, first comparator IC1A noninverting input
Reference voltage Ub=(R4/R4+R2) * VCC, reference voltage Ua=(R3/R3+R1) * of first comparator IC1A inverting input terminal
The output end voltage of VCC, first comparator IC1A are Uf, and Uf is detection signal voltage value, and reference voltage is set as Ua greater than Ub.
When circuit of power factor correction 10 works normally, Ua is greater than Ub, and first comparator IC1A output end voltage Uf is low
Level, driving unit 40, control unit 50 input terminal be that low level is effective.The low level inspection of first comparator IC1A output
The input terminal that signal is fed directly to driving unit 40 by conducting wire is surveyed, meanwhile, first comparator IC1A exports low level inspection
Signal is surveyed to control unit 50,50 pairs of detection signals of control unit are handled, and judge electric current not after overcurrent, control unit 50 is defeated
The input terminal of signal to driving unit 40 is controlled out.In this way, the output end output drive signal of driving unit 40 is to switching tube
The grid of IGBT charges to the parasitic capacitance of switching tube IGBT grid, and switching tube IGBT is open-minded, and circuit of power factor correction 10 is permitted
Perhaps it works.At this point, the electric current for flowing through sampling resistor R61 is Iac, sampling resistor R61 partial pressure, voltage Ua is reduced, if Ua is still big
In Ub, IGBT current foldback circuit will not enter overcurrent protection, and circuit of power factor correction 10 maintains to work normally.
Ua is caused to be less than Ub if the control abnormal signal or power grid surge, voltage of circuit of power factor correction 10 are too strong,
First comparator IC1A overturning, first comparator IC1A output voltage Uf are high level, so that protection location 30 is directly by leading
Line exports the detection signal of high level to the input terminal of driving unit 40, and driving unit 40 stops output drive signal, switching tube
IGBT stops working, and completes the hardware protection of switch tube IGBT；Meanwhile protection location 30 exports the detection signal of high level extremely
Control unit 50,50 pairs of detection signals of control unit are handled, and after judging overcurrent, software is by the output of control unit 50
Turn off, completes the software protection of switch tube IGBT.As Ua=Ub, the threshold points in overcurrent protection, by this threshold points,
Overcurrent Iac=[VCC- (VCC-Ub)/R1* (R3+R1)]/R61 can be calculated.
Embodiment 4
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, protect
Protecting unit 30 further includes latching circuit 302, to prevent the secondary overturning of output of first comparator IC1A, latching circuit 302 it is defeated
Enter end to be connected with the output end of first comparator IC1A, the first of the output end of latching circuit 302 and first comparator IC1A is defeated
Enter end to be connected, latching circuit 302 is one-way conduction circuit.
Ua is caused to be less than Ub when the control abnormal signal or power grid surge, voltage of circuit of power factor correction 10 are too strong
When, first comparator IC1A overturning, it is high level that first comparator IC1A, which exports Uf, and switching tube IGBT stops working.It is electric at this time
Pressure Uf is applied to Ub by latching circuit 302, is lifted Ub voltage, it is ensured that first comparator IC1A will not increase secondary because of Ua
Overturning.
In this way, due to the effect of latching circuit 302, switching tube IGBT in the present embodiment stops working because of overcurrent
When, first comparator IC1A will not increase secondary overturning because of Ua, even if control unit 50 judges incorrectly, not stop output control letter
Number to driving unit 40 input terminal, switching tube IGBT will not be automatic open-minded, thus the IGBT overcurrent protection in the present embodiment
Circuit has self-locking function, avoids switching tube IGBT shutdown, the runaway condition that the output of control unit 50 is not switched off, and really
Circuit does not generate oscillation after having protected switching tube IGBT shutdown.
Embodiment 5
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, protect
Protecting unit 30 further includes start-up circuit 303, to release locking of the latching circuit 302 to circuit, the input terminal of start-up circuit 303 with
The output end of first comparator IC1A is connected, the output end and the signal output CLR phase of control unit 50 of start-up circuit 303
Even.
After switching tube IGBT is protected, to be again turned on, CLR mouthfuls of signal output of control unit 50 can be made to export one
Low level signal, the activated circuit 303 of Uf discharge, and Uf level is pulled low, it can be ensured that Ub voltage is restored to initial baseline point, then
Signal output CLR switchs to high level again, and switching tube IGBT can be connected, and circuit of power factor correction 10 can task again.
In this way, to be again turned on, directly passing through software after switching tube IGBT overcurrent protection in the present embodiment and releasing lock
Determine function, guard time can freely be adjusted by software, so that the guard time of the IGBT current foldback circuit in the present embodiment can
Freely adjust.
Embodiment 6
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, from
Lock circuit 302 includes first diode D1, and the cathode of first diode D1 is connected with the first input end of first comparator IC1A,
Anode is connected with the output end of first comparator IC1A.
In the present embodiment, after switching tube IGBT stops working, voltage Uf directly passes through first diode D1 and is applied to Ub, makes
Ub voltage is lifted, it is ensured that first comparator IC1A will not increase secondary overturning because of Ua.
In this way, voltage Uf can only be applied to Ub through first diode D1 due to the unilateal conduction of first diode D1, guarantee
The stability of circuit.And first diode D1 be connected when resistance very little, voltage Uf pass through first diode D1 when pressure drop compared with
Small, the voltage for being applied to Ub is bigger, and Ub voltage is lifted higher, and the self-locking function of latching circuit 302 is stronger.
Embodiment 7
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, open
Dynamic circuit 303 includes the second diode D2, and the anode of the second diode D2 is connected with the output end of first comparator IC1A, cathode
It is connected with the signal output CLR of control unit 50.
In this implementation, after switching tube IGBT is protected, to be again turned on, CLR mouthfuls of the signal output of control unit 50
A low level signal is exported, Uf directly discharges through the second diode D2, resistance very little when due to the second diode D2 conducting, to electricity
The inhibition very little of stream, faster, level is pulled low faster the velocity of discharge of Uf, it can be ensured that Ub voltage quickly recovers to initially
Datum mark, start-up circuit 303 release latching circuit 302 to the speed of the locking of circuit faster.
Embodiment 8
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, protect
Shield unit 30 further includes the second comparison circuit 304, and the second comparison circuit 304 includes the second comparator IC1B, the 6th resistance R6, the
Seven resistance R7, the 8th resistance R8, the 9th resistance R9, the second DC power supply VDD.Second comparator IC1B include first input end and
Second input terminal of the second input terminal, the second comparator IC1B is connected with the output end of first comparator IC1A, the second comparator
The first input end of IC1B is divided into two-way, is grounded all the way through the 7th resistance R7, another way is through the 6th resistance R6 and the second direct current
Source VDD is connected；The output end of second comparator IC1B is divided into two-way, is connected all the way through the 8th resistance R8 with power supply, another
One end of nine resistance R9 of Lu Yu is connected；The other end of 9th resistance R9 respectively with the input terminal of control unit 50, driving unit
40 input terminal is connected.
6th resistance R6, the 7th resistance R7 are as divider resistance, and the 8th resistance R8 is as the second comparator IC1B output end
Pull-up resistor, current-limiting resistance of the 9th resistance R9 as the second comparator IC1B output end.
In many cases, when circuit of power factor correction 10 works normally, first comparator IC1A output is low electricity
Flat, when circuit overcurrent, first comparator IC1A output is high level.It and is input terminal in control unit 50 and driving unit 40
When high level is effective, input high level exports high level, the high level detection signal of first comparator IC1A output can make to control
Unit 50 and driving unit 40 export high level, cannot achieve the purpose that on-off switching tube IGBT.In the present embodiment, work as power
When 10 overcurrent of factor correcting circuit, the high level that first comparator IC1A is exported can be detected letter by the second comparison circuit 304
Number it is converted into low level detection signal, so that control unit 50 and driving unit 40 is exported low level, reach on-off switching tube
The purpose of IGBT.
Preferably the first input end of the second comparator IC1B is its non-inverting input terminal in the present embodiment, and the second input terminal is it
Reverse input end.The voltage of comparator IC1B inverting input terminal is Uf, the reference voltage Ud=of comparator IC1B noninverting input
(R7/R7+R6)*VDD.Reference voltage is set as Ua greater than Ub, while meeting Uf when Uf is high level and being greater than Ud.Power factor school
When positive circuit 10 works normally, Ua is greater than Ub, and comparator IC1A output voltage Uf is low level, and Uf is less than Ud, comparator IC1B
The detection signal of output end output high level；When circuit overcurrent, comparator IC1A output voltage Uf is high level；Uf is greater than Ud,
Comparator IC1B reversion, comparator IC1B export low level detection signal.
In this way, user cooperates in selection and protection circuit 30 in the present embodiment due to the effect of the second comparison circuit 304
When the control unit 50 and driving unit 40 of work, optional range is bigger, and freedom degree is higher.
Embodiment 9
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 2, protect
Protecting unit 30 further includes first capacitor C1, the second capacitor C2, third capacitor C3, the 4th capacitor C4, the 5th capacitor C5, first capacitor
C1, the second capacitor C2, third capacitor C3, the 4th capacitor C4, the 5th capacitor C5 one end be grounded, the other end of first capacitor C1
It is connected with the second output terminal of first comparator IC1A, the first input of the other end and first comparator IC1A of the second capacitor C2
End is connected, and the other end of third capacitor C3 is connected with the output end of first comparator IC1A, the other end of the 4th capacitor C4 and the
The first input end of two comparator IC1B is connected, and the other end of the 5th capacitor C5 is connected with the 9th resistance R9.
First capacitor C1, the second capacitor C2, third capacitor C3, the 4th capacitor C4, the 5th capacitor C5 are used as filter capacitor,
Suitable capacitance is selected by calculating, interference of some noise signals to circuit can be filtered, allows detection signal closer to very
Real value, false triggering caused by avoiding because of noise signal.The reliability of circuit is higher.
Embodiment 10
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 3, drive
Moving cell 40 includes a driving chip 401, the tenth resistance R10, eleventh resistor R11.The input terminal of driving chip 401 is divided into three
Road is connected with the output end PFC_PWM of control unit 50 through the tenth resistance R10 all the way, is grounded all the way through eleventh resistor R11,
It is connected all the way with the output end of protection location 30；The output end of driving chip 401 is connected with the grid of switching tube IGBT.
Preferred driving chip 401 is two-way low-voltage driving chip I R4427 in the present embodiment, and chip I R4427 includes 8 and draws
Foot: NC, NC, INA, OA, GND, Vcc, INB, OB.Wherein, pin INA, INB is two-way input port, and pin OA, OB are that two-way is defeated
Outlet, pin INA corresponding pin OA, pin INB corresponding pin OB, pin INA, INB are that high level is effective.Pin INA,
When INB is high level, pin OA, OB export high level；When pin INA, INB are low level, pin OA, OB export low level.
In the present embodiment, driving unit 40 further includes the 6th capacitor C6, the 7th capacitor C7.
Pin INA, INB are connected through the tenth resistance R10 with the output end PFC_PWM of control unit 50, through the 11st
Resistance R11 ground connection, is connected with the output end of protection location 30.6th capacitor C6 is in parallel with eleventh resistor R11, the 7th capacitor
The one end C7 ground connection, the other end are connected with Vcc pin, the DC power supply of IR4427 respectively.Pin OA, OB are with switching tube IGBT's
Grid is connected.Tenth resistance R10 is as current-limiting resistance, and eleventh resistor R11 is as divider resistance, the 6th capacitor C6, the 7th electricity
Appearance C7 is filter capacitor.
When circuit of power factor correction 10 works normally, the input of pin INA, INB are high level, thus pin
OA, OB export the parasitic capacitance charging of high level switch tube IGBT grid, switching tube IGBT conducting；PFC electricity
When 10 overcurrent of road, the input of pin INA, INB are low level, so that pin OA, OB export low level, switching tube IGBT grid
The charge of the parasitic capacitance storage of pole discharges, switching tube IGBT shutdown.
Embodiment 11
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 3, drive
Moving cell 40 further includes twelfth resistor R12, thirteenth resistor R13, the 14th resistance R14.Thirteenth resistor R13 and the 14th
One end after resistance R14 is in parallel is connected with pin OA, OB of driving chip 401 respectively through twelfth resistor R12, the other end with open
The grid for closing pipe IGBT is connected.
In the present embodiment, thirteenth resistor R13, the 14th resistance R14 are used as current-limiting resistance.Circuit of power factor correction
When 10 normal work, protection location 30 exports the input terminal of high level to chip I R4427, and the output pin of chip I R4427 is defeated
The grid of the parasitic gate capacitor charging of high level switch tube IGBT out, twelfth resistor R12 adjustable switch pipe IGBT is posted
The charging rate of raw capacitor avoids switching tube IGBT from burning because charging too fastly.
Embodiment 12
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 3, drive
Moving cell 40 further includes third diode D3, and the cathode of third diode D3 is connected with pin OA, OB of driving chip 401, sun
Pole connects the common end of twelfth resistor R12, thirteenth resistor R13 and the 14th resistance R14.
When switching tube IGBT is turned off, driving unit 40 exports low level, since the pressure drop of third diode D3 is less than identical
The pressure drop that generates on twelfth resistor R12 of driving cut-off current, the charge of the grid capacitance storage of switching tube IGBT pass through the
Three diode D3 repid discharges.
In this way, switching tube IGBT can be realized quickly when circuit overcurrent in the present embodiment due to the effect of third diode D3
Shutdown, protection speed faster, and reduce the loss of circuit.
Embodiment 13
IGBT current foldback circuit as described above, the present embodiment are different from place and are, as shown in connection with fig. 3, drive
Moving cell 40 further includes zener diode ZD1 and the 15th resistance R15, the plus earth of zener diode ZD1, and cathode connection is opened
The grid of pipe IGBT, the common end of thirteenth resistor R13 and the 14th resistance R14 are closed, the 15th resistance R15 is connected to switching tube
Between the grid and ground connection of IGBT.
Insulation resistance in switching tube IGBT between metal-oxide-semiconductor grid and drain electrode and source electrode is very high, and insulating layer is very thin, and grid is very
It is easy stored charge to puncture insulating layer and damage metal-oxide-semiconductor, to be hit if there is high voltage is added to grid also in use
It wears insulating layer and damages metal-oxide-semiconductor.The gate connected in parallel zener diode ZD1 of switching tube IGBT in the present embodiment can limit grid electricity
Zener diode ZD1 pressure stabilizing value is pressed in hereinafter, preventing switching tube IGBT grid breakdown.15th resistance R15 is as drop-down electricity
Resistance, the electrostatic charge of releasable grid do not allow charge accumulated, prevent switching tube IGBT grid by electrostatic breakdown.
Embodiment 14
The present embodiment provides a kind of air conditioners, including IGBT current foldback circuit described in any of the above-described embodiment.In this way,
Due to the effect of the IGBT current foldback circuit, the protecting effect of the air conditioner switch tube IGBT in the present embodiment is more preferable,
Protect speed faster.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all in essence of the invention
Within mind and principle, any modification, equivalent replacement, improvement and so on be should all be included in the protection scope of the present invention.
Claims (10)
1. a kind of IGBT current foldback circuit, for carrying out overcurrent to the switching tube (IGBT) in circuit of power factor correction (10)
Protection, which is characterized in that including current sampling unit (20), protection location (30), driving unit (40) and control unit
(50)；Wherein,
The current sampling unit (20) respectively with the emitter of the switching tube (IGBT), the circuit of power factor correction
(10) the DC side cathode of rectifier bridge (BG1), the input terminal of the protection location (30) are connected in, the current sampling unit
(20) the output electric current of the circuit of power factor correction (10) is sampled, obtains sample rate current, and the sampling is electric
Stream is delivered to the input terminal of the protection location (30)；
The protection location (30) is used to convert sampled voltage for the sample rate current and compared with reference voltage, one inspection of output
Survey signal；The output end of the protection location (30) is divided into two-way, is connected all the way with the input terminal of described control unit (50), separately
It is connected all the way by a conducting wire with the input terminal of the driving unit (40)；
The output end of described control unit (50) is connected with the input terminal of the driving unit (40), described control unit (50) root
The driving unit (40) is controlled according to the one control signal of detection signal output of the protection location (30) output；
The output end of the driving unit (40) is connected with the grid of the switching tube (IGBT), and the driving unit (40) is used for
According to the detection signal of the protection location (30) output and the control signal of described control unit (50) output
Control the conducting and shutdown of the switching tube (IGBT).
2. IGBT current foldback circuit according to claim 1, which is characterized in that the protection location (30) includes first
Comparison circuit (301), first comparison circuit (301) include first resistor (R1), second resistance (R2), 3rd resistor
(R3), the 4th resistance (R4), the 5th resistance (R5), first comparator (IC1A), the first DC power supply (VCC), first ratio
It include first input end and the second input terminal compared with device (IC1A)；The first input end of the first comparator (IC1A) is divided into two
Road is grounded through the 4th resistance (R4) all the way, and another way is through the second resistance (R2) and the first DC power supply (VCC) phase
Even；Second input terminal of the first comparator (IC1A) is divided into two-way, all the way through the 3rd resistor (R3) respectively with it is described
The DC side cathode of rectifier bridge (BG1), the current sampling unit (20) are connected, and another way is through the first resistor (R1) and the
One DC power supply (VCC) is connected；The input with described control unit (50) respectively of the output end of the first comparator (IC1A)
End, the input terminal of the driving unit (40), one end of the 5th resistance (R5) are connected；5th resistance (R5) it is another
End is connected with power supply.
3. IGBT current foldback circuit according to claim 2, which is characterized in that the protection location (30) further includes certainly
Lock circuit (302), to prevent the secondary overturning of output of the first comparator (IC1A), the input of the latching circuit (302)
End is connected with the output end of the first comparator (IC1A), and the output end of the latching circuit (302) is compared with described first
The first input end of device (IC1A) is connected, and the latching circuit (302) is one-way conduction circuit.
4. IGBT current foldback circuit according to claim 2, which is characterized in that the protection location (30) further includes opening
Dynamic circuit (303), to release locking of the latching circuit (302) to circuit, the input terminal of the start-up circuit (303) and institute
The output end for stating first comparator (IC1A) is connected, output end and described control unit (50) of the start-up circuit (303)
Signal output (CLR) is connected.
5. IGBT current foldback circuit according to claim 2, which is characterized in that the latching circuit (302) includes the
The cathode of one diode (D1), the first diode (D1) is connected with the first input end of the first comparator (IC1A),
Anode is connected with the output end of the first comparator (IC1A).
6. IGBT current foldback circuit according to claim 4, which is characterized in that the start-up circuit (303) includes the
The anode of two diodes (D2), second diode (D2) is connected with the output end of the first comparator (IC1A), cathode
It is connected with the signal output (CLR) of described control unit (50).
7. according to the IGBT current foldback circuit any in claim 2-6, which is characterized in that the protection location (30)
It further include the second comparison circuit (304), second comparison circuit (304) includes the second comparator (IC1B), the 6th resistance
(R6), the 7th resistance (R7), the 8th resistance (R8), the 9th resistance (R9), the second DC power supply (VDD), second comparator
It (IC1B) include first input end and the second input terminal；Second input terminal of second comparator (IC1B) and described first compares
Output end compared with device (IC1A) is connected, and the first input end of second comparator (IC1B) is divided into two-way, all the way through described the
Seven resistance (R7) ground connection, another way are connected through the 6th resistance (R6) with second DC power supply (VDD)；Second ratio
Output end compared with device (IC1B) is divided into two-way, is connected all the way through the 8th resistance (R8) with the power supply, another way with
One end of 9th resistance (R9) is connected；The other end of 9th resistance (R9) is defeated with described control unit (50) respectively
Enter end, the input terminal of the driving unit (40) is connected.
8. IGBT current foldback circuit according to claim 7, which is characterized in that the protection location (30) further includes
One capacitor (C1), the second capacitor (C2), third capacitor (C3), the 4th capacitor (C4), the 5th capacitor (C5), the first capacitor
(C1), second capacitor (C2), the third capacitor (C3), the 4th capacitor (C4), the 5th capacitor (C5) one
End is grounded, and the other end of the first capacitor (C1) is connected with the second output terminal of the first comparator (IC1A), described
The other end of second capacitor (C2) is connected with the first input end of the first comparator (IC1A), the third capacitor (C3)
The other end is connected with the output end of the first comparator (IC1A), and the other end of the 4th capacitor (C4) and described second compares
First input end compared with device (IC1B) is connected, and the other end of the 5th capacitor (C5) is connected with the 9th resistance (R9).
9. according to the IGBT current foldback circuit any in claim 2-8, which is characterized in that the current sampling circuit
Including sampling resistor (R61), described sampling resistor (R61) one end respectively with the rectifier bridge (BG1) DC side cathode, described
Three resistance (R3) are connected, and the other end is connected and is grounded with the emitter of the switching tube (IGBT).
10. a kind of air conditioner, which is characterized in that including the described in any item IGBT current foldback circuits of such as claim 1-9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811040798.7A CN109004620A (en) | 2018-09-07 | 2018-09-07 | A kind of IGBT current foldback circuit and air conditioner |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811040798.7A CN109004620A (en) | 2018-09-07 | 2018-09-07 | A kind of IGBT current foldback circuit and air conditioner |
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| CN109004620A true CN109004620A (en) | 2018-12-14 |
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| CN201811040798.7A Pending CN109004620A (en) | 2018-09-07 | 2018-09-07 | A kind of IGBT current foldback circuit and air conditioner |
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| CN111478286A (en) * | 2020-03-17 | 2020-07-31 | 海信（山东）空调有限公司 | PFC overcurrent protection circuit, air conditioner controller and air conditioner |
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