CN104779584A - Frequency changer detection protection circuit - Google Patents
Frequency changer detection protection circuit Download PDFInfo
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- CN104779584A CN104779584A CN201410015176.4A CN201410015176A CN104779584A CN 104779584 A CN104779584 A CN 104779584A CN 201410015176 A CN201410015176 A CN 201410015176A CN 104779584 A CN104779584 A CN 104779584A
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Abstract
The present invention discloses a frequency changer detection protection circuit. The frequency changer detection protection circuit comprises a transistor voltage drop sampling unit, a comparator unit, a negative voltage clamping unit, a 3120 optocoupler driver element, a reference potential unit, an overcurrent protection output circuit unit and an IGBT main circuit unit. The input of the transistor voltage drop sampling unit is connected to the IGBT main circuit unit; the input of the comparator unit is connected to the output of the transistor voltage drop sampling unit; the input of the negative voltage clamping unit is connected to the output of the 3120 optocoupler driver element, and the output of the negative voltage clamping unit is connected to the comparator unit; the input of the reference potential unit is connected to a +15 V voltage source, and the output of the reference potential unit is connected to the comparator unit; the input of the overcurrent protection output circuit unit is connected to the output of the comparator unit. According to the frequency changer detection protection circuit, the transistor voltage drop of an IGBT is sampled to detect the current flowing through the IGBT; the protection is quick, the cost is low, and the efficient current detection method can be widely popularized in engineering application.
Description
Technical field
The present invention relates to frequency converter IGBT inverter bridge and drive protection field, detect protective circuit in particular for frequency converter IGBT device short-circuit protection and the excessive a kind of frequency converter of electric current.
Background technology
At present, the application of frequency converter in Industry Control is more and more extensive, and frequency conversion speed-adjusting system has become the main flow mode of speed regulation of power electronics transmission field;
Frequency converter is the core control devices in whole AC variable-frequency speed regulation system, its stability and the impact of reliability on whole system most important.When breaking down, what primarily will do is drop to minimum by the damage that fault is brought as far as possible, avoids the key components of frequency converter to be damaged.Frequency converter self has various protective circuit, as, overvoltage, under-voltage, the defencive function such as overtemperature, overload, overcurrent, short circuit current, to ensure that frequency converter is when running into above-mentioned unusual condition, reasonably reduce loss, reliably turn off the output of IGBT device;
IGBT is full-control type power semiconductor, is voltage-type type of drive, has driving power little, the advantage that saturated tube voltage drop is low, is the first-selected power device of most of frequency converter three phase inverter bridge.In most cases, it is that IGBT exits saturation region and enters amplification region that the reason that IGBT damages mainly contains three kinds: one, makes devices switch loss and conduction loss become large; Two is that the direct conducting of upper and lower bridge arm occurs IGBT, instantaneously by producing high short circuit current, IGBT is damaged; Three is that the outlet side of frequency converter is short-circuited or motor stall, can flow through very large electric current, thus cause electric and electronic power device IGBT part to damage in frequency converter.
Summary of the invention
The technical problem to be solved in the present invention is; there is provided a kind of response rapidly; turn off reliable; the detection protective circuit of the frequency converter that cost performance is higher; realize the Real-Time Monitoring to IGBT power device undersaturation district tube voltage drop; be short-circuited and reliable turn-off during overcurrent at IGBT, the short circuit and super-high-current flow through in IGBT can be detected effectively in time, reliablely and stablely turn off the protecting control circuit of power electronic device.
The technical scheme that the present invention solves its technical problem is; a kind of frequency converter detects protective circuit, comprises tube voltage drop sampling unit, comparator unit, negative pressure clamping unit, 3120 optocoupler driver elements, reference potential unit, overcurrent protection output circuit unit and IGBT main circuit unit.Wherein:
The input of described tube voltage drop sampling unit is connected to IGBT main circuit unit, for detecting the tube voltage drop flowing through electric current in reflection IGBT;
The input of described comparator unit is connected to the output of tube voltage drop sampling unit, when the magnitude of voltage for the reflection IGBT tube voltage drop sampled reaches the threshold value of certain setting, and output low level magnitude of voltage;
The input of described overcurrent protection output circuit unit is connected to the output of comparator unit, for when comparator unit output low level, and the optocoupler diode current flow of output unit, output low level guard signal;
The input of described negative pressure clamping unit is connected to 3120 driving optocoupler unit, the input of comparator unit is connected to the output of negative pressure clamping unit, for at IGBT blocking interval, by the reverse input end clamper of comparator unit a negative value, avoid the generation of protection by mistake;
The input of described reference potential unit is connected to+15V power supply, and output is connected to comparator unit, provides fixing reference potential for giving the in-phase input end of comparator unit.
The input of described IGBT main circuit unit is connected to DC bus, output is connected to tube voltage drop sampling unit, the collector electrode of upper 3 pipes of this IGBT main circuit unit is connected to described tube voltage drop sampling unit, the current value that this unit is used for flowing through according to IGBT becomes the phenomenon of certain curved line relation with tube voltage drop magnitude of voltage, detect the short circuit and super-high-current that occur in IGBT.
The beneficial effect that the present invention is compared with the prior art is, circuit of the present invention excessive detection protective circuit direct-detection power device tube voltage drop, response speed is faster, in most cases, the short circuit current tolerance time of IGBT device is shorter, require high to the reflecting time of protective circuit, short-circuit signal faster responsiveness ensure that the reliably protecting to greatest extent to IGBT device, by the collector electrode of sampled power device IGBT and the tube voltage drop at emitter two ends, realize detecting the current sample of the upper brachium pontis power IGBT pipe of three, inversion bridge, when there is upper and lower bridge arm shoot through or electric current is excessive, reliably turn off 6 road PWM drive singal, thus reliably shutoff 6 power IGBT manage.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described.
Fig. 1 is the logic function block diagram that a kind of frequency converter detects protective circuit, and wherein, the IGBT in IGBT main circuit unit is insulated gate bipolar transistor, and the driving optocoupler 3120 in 3120 optocoupler driver elements is IGBT gate-drive optocouplers.
Fig. 2 is the circuit diagram that a kind of frequency converter detects protective circuit, wherein, after resistance R2 connects with diode D2, connects DC bus anode; After resistance R5 connects with diode D1, connect 6 pin driving optocoupler 3120.
Fig. 3 is that a kind of frequency converter detects in 3120 optocoupler driver elements of protective circuit, drives the functional block diagram of optocoupler 3120.Wherein, N/C is sky pin, without connecting; ANODE is primary diode anode; CATHODE is primary diode negative electrode; VO secondaryly recommends output;
it is secondary power pin;
secondary reference ground.
Embodiment
As shown in Figure 1; a kind of frequency converter detects protective circuit, comprises tube voltage drop sampling unit 11, comparator unit 12, negative pressure clamping unit 13,3120 optocoupler driver element 14, reference potential unit 15, overcurrent protection output circuit unit 16 and IGBT main circuit unit 17.Wherein, the input of tube voltage drop sampling unit 11 is connected to the collector electrode of the IGBT power device of IGBT main circuit unit 17, for detecting the tube voltage drop at IGBT power device collector electrode C and emitter E two ends in frequency converter running; The input of comparator unit 12 is connected to the output of tube voltage drop sampling unit 11, and for when reference potential higher than in-phase input end of the anti-phase input terminal potential of comparator unit 12, output low level, makes to export optocoupler conducting; The input of negative pressure clamping unit 13 is connected to 6 pin (driving the functional block diagram of optocoupler 3120 as shown in Figure 3) of the driving optocoupler 3120 of 3120 optocoupler driver elements 14, output is connected to the inverting input of comparator unit 12, for at IGBT blocking interval, by the inverting input clamper of comparator unit 12 at a fixing negative potential; The input of reference potential unit 15 is connected to+15V power supply, and output is connected to the in-phase input end of comparator unit 12, provides fixing reference potential for giving the in-phase input end of comparator unit 12; The input of 3120 optocoupler driver elements 14 is connected to frequency converter 6 road PWM drive singal, output is connected to 6 IGBT power devices of IGBT main circuit unit 17, in the present embodiment, 3120 optocoupler driver element 14 circuit are for realizing the interlocking of 6 road PWM drive singal, amplification and isolation, when driving 6 pin output+15VS of optocoupler 3120, corresponding IGBT is open-minded, and when driving 6 pin output-9.1V of optocoupler 3120, IGBT is reliable turn-off then; The input of IGBT main circuit unit 17 is connected to high direct voltage bus main circuit, output is connected to three phase AC induction machine, the collector electrode of upper 3 pipes of this IGBT main circuit unit 17 is connected to the input of described tube voltage drop sampling single 11, in the present embodiment, when the increase flow through in IGBT pipe, the tube voltage drop of IGBT can rise according to certain curve; The input of overcurrent protection output circuit unit 16 is connected to the output of comparator unit 12; during for realizing comparator unit 12 output low level; the diode current flow of the optocoupler of overcurrent protection output circuit unit 16; when comparator unit 12 exports high level; the diode of the optocoupler of overcurrent protection output circuit unit 16 turns off, and makes overcurrent protection output circuit unit 16 export low and high level signal with this.When there is short circuit current or the excessive situation of electric current in foregoing circuit in IGBT power device, can output low level signal, low level signal is connected in the lockout circuit of rear class, blocks 6 road PWM drive singal rapidly, reliably protects IGBT pipe not to be damaged.
As shown in Figure 2, tube voltage drop sampling unit 11 comprises the second diode D2, the second resistance R2, the first resistance R1, the first voltage-stabiliser tube Z1, the first electric capacity C1, the second electric capacity C2.Resistance R1 is connected between+15V power supply and electric capacity C2; Voltage-stabiliser tube Z1 is in parallel with electric capacity C2, is connected to reference to ground VHE; The negative pole of diode D2 is connected to DC bus anode (i.e. IGBT pipe collector), and one end of resistance R2 is connected to the positive pole of diode D2, and the other end is connected to the negative pole of voltage-stabiliser tube Z1.IGBT conduction period ,+15V is charged to electric capacity C2 by resistance R2, and+15V is by resistance R1, resistance R2, diode D2, IGBT collector electrode simultaneously, and emitter circuit discharges.During IGBT normally, tube voltage drop is according to the proportionate relationship with electric current on a rational curve, and when being short-circuited or electric current is excessive, current break, tube voltage drop raises suddenly, causes the current potential of voltage-stabiliser tube Z1 negative pole to raise.
Comparator unit 12 comprises the 3rd resistance R3, the 4th resistance R4, the 6th resistance R6, the 9th resistance R9, the second comparator unit U2-A, the 3rd electric capacity C3, the 4th electric capacity C4, in an embodiment, resistance R3, resistance R4 connect with resistance R6, the tie point of resistance R4 and resistance R6 is connected to the inverting input of comparator U2-A, resistance R9 is connected between+15V and 1 pin of comparator U2-A, as OC door pull-up resistor.When electric current in IGBT increases, the current potential of voltage-stabiliser tube Z1 negative pole rises, and the current potential of comparator U2-A inverting input 2 pin rises thereupon, after its amplitude exceedes the magnitude of voltage of certain current value of correspondence of comparator U2-A in-phase input end 3 pin, comparator U2-A overturns, 1 pin output low level.
Negative pressure clamping unit 13 comprises the first diode D1, the 5th resistance R5, and in an embodiment, the negative pole of diode D1 is connected to 6 pin driving optocoupler 3120, and resistance R5 and D1 connects, and is connected to comparator U2-A inverting input 2 pin.At IGBT blocking interval, drive 6 pin of optocoupler 3120 to export negative voltage-9.1V, by diode D1, resistance R5 by the 2 pin clampers of comparator U2-A at a specific negative potential.
Reference potential unit 15 comprises voltage reference chip U1, the 7th resistance R7, the first electrochemical capacitor CE1, in an embodiment, one end of resistance R7 is connected on+15V, one end is connected on the positive pole of electrochemical capacitor CE1,1 pin and 3 pin of voltage reference chip U1 are connected together, be connected to electrochemical capacitor CE1 positive pole, the negative pole of electrochemical capacitor CE1 and 2 pin of voltage reference U1 are connected together, and are the emitters of IGBT with being connected to the VHE(reference of reference ground).+ 15V is added on voltage reference chip U1 by current-limiting resistance R7, and voltage reference U1 produces reference voltage (as 2.5V) very accurately, is connected to the normal phase input end of comparator U2-A.
Overcurrent protection output circuit unit 16 comprises the tenth resistance R10, the first high speed photo coupling PC1, the 8th resistance R8, the 5th electric capacity C5, the 6th electric capacity C6; in an embodiment; 2 pin of high speed photo coupling PC1 are connected to output 1 pin of comparator U2-A; one end of resistance R10 is connected to+15V; the other end is connected to 1 pin of high speed photo coupling PC1; + 5V is connected to 6 pin of high speed photo coupling PC1; 5 pin of high speed photo coupling PC1 are connected to signal with reference to ground by resistance R8; 4 pin of high speed photo coupling PC1 are signal output parts, and shunt capacitance C5 is connected to reference to ground.When 1 pin of comparator U2-A exports high level, the diode cut-off of high speed photo coupling PC1, the 4 pin position high level of high speed photo coupling PC1, no signal exports; When the 1 pin output low level of comparator U2-A, the diode current flow of high speed photo coupling PC1,4 pin output low levels, output short-circuit or the overcurrent protection signal of high speed photo coupling PC1.
Shown in Fig. 3,6 pin of optical coupler 3120 are
, when elementary diode current flow,
exporting is pulled upward to close by inner push-pull circuit
high level, when primary diode ends,
pulled down to by the push-pull circuit of inside
with reference to ground.
In foregoing circuit, the collector electrode of the upper three brachium pontis IGBT of IGBT main circuit unit links together, as the sampling origin of tube voltage drop sampling unit 11, electric capacity C2 is the Primary Component of sampling unit, IGBT blocking interval, the pressure drop at electric capacity C2 two ends is negative, now sample circuit does not detect IGBT tube voltage drop, overcurrent protection output unit 16 can not the guard signal of output low level, IGBT conduction period, curent change situation in the pressure drop reflection IGBT at C2 two ends, when the situation of bridgc arm short or overcurrent occurs, in time by optocoupler output circuit output low level guard signal, thus promptly perform the action that next step turns off IGBT device.
The above; be only the present invention's preferably embodiment, but protection scope of the present invention is not limited thereto, any research staff being familiar with the art is in technical scope disclosed by the invention; institute's light facile change of energy or replacement, all should be encompassed in protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection range of claim.
Claims (4)
1. frequency converter detects a protective circuit, comprises tube voltage drop sampling unit, comparator unit, negative pressure clamping unit, reference potential unit, overcurrent protection output circuit unit, 3120 optocoupler driver elements and IGBT main circuit unit, it is characterized in that,
The input of described tube voltage drop sampling unit is connected to IGBT main circuit unit, for detecting the tube voltage drop flowing through electric current in reflection IGBT;
The input of described comparator unit is connected to the output of tube voltage drop sampling unit, when the magnitude of voltage for the reflection IGBT tube voltage drop sampled reaches the threshold value of certain setting, and output low level magnitude of voltage;
The input of described overcurrent protection output circuit unit is connected to the output of comparator unit, for when comparator unit output low level, and the optocoupler diode current flow of output unit, output low level guard signal;
The input of described negative pressure clamping unit is connected to 3120 driving optocoupler unit, the input of comparator unit is connected to the output of negative pressure clamping unit, for at IGBT blocking interval, by the reverse input end clamper of comparator unit a negative value, avoid the generation of protection by mistake;
The input of described reference potential unit is connected to+15V power supply, and output is connected to comparator unit, provides fixing reference potential for giving the in-phase input end of comparator unit;
The input of described IGBT main circuit unit is connected to DC bus, output is connected to tube voltage drop sampling unit, the current value that this unit is used for flowing through according to IGBT becomes the phenomenon of certain curved line relation with tube voltage drop magnitude of voltage, detect the short circuit and super-high-current that occur in IGBT.
2. frequency converter according to claim 1 detects protective circuit, it is characterized in that, when 3120 driver element optocouplers export high level, IGBT conducting, when 3120 optocoupler driver elements export negative level, IGBT turns off.
3. frequency converter according to claim 1 detects protective circuit; it is characterized in that; described tube voltage drop sampling unit comprises the first resistance R1, the second electric capacity C2, the second diode D2, the second resistance R2, the first voltage-stabiliser tube Z1, and+15V power supply forms charge circuit by the first resistance R1, the second electric capacity C2.
4. frequency converter according to claim 1 detects protective circuit, and it is characterized in that, described overcurrent protection output circuit unit comprises high speed photo coupling, and the low and high level that the diode of high speed photo coupling exports according to comparator turns off and conducting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410015176.4A CN104779584A (en) | 2014-01-14 | 2014-01-14 | Frequency changer detection protection circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410015176.4A CN104779584A (en) | 2014-01-14 | 2014-01-14 | Frequency changer detection protection circuit |
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| CN104779584A true CN104779584A (en) | 2015-07-15 |
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|---|---|---|---|
| CN201410015176.4A Pending CN104779584A (en) | 2014-01-14 | 2014-01-14 | Frequency changer detection protection circuit |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN107219844A (en) * | 2017-06-20 | 2017-09-29 | Tcl空调器(中山)有限公司 | Power model startup self-detection method, device and storage medium |
| CN109328429A (en) * | 2017-05-30 | 2019-02-12 | 普罗蒂恩电子有限公司 | Controller for motor |
| CN109951908A (en) * | 2017-12-21 | 2019-06-28 | 佛山市顺德区美的电热电器制造有限公司 | The drive control circuit and drive control method of electromagnetic heating system and its IGBT |
| CN113625145A (en) * | 2021-08-12 | 2021-11-09 | 合肥恒钧检测技术有限公司 | Equipment and method for testing optocoupler |
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| CN203376387U (en) * | 2013-06-19 | 2014-01-01 | 山东朗进科技股份有限公司 | Over-voltage detection circuit and PFC circuit using the same |
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| CN101399491A (en) * | 2007-11-06 | 2009-04-01 | 中国科学院电工研究所 | Overcurrent protection circuit for photovoltaic DC-to-AC converter |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN109328429A (en) * | 2017-05-30 | 2019-02-12 | 普罗蒂恩电子有限公司 | Controller for motor |
| CN107219844A (en) * | 2017-06-20 | 2017-09-29 | Tcl空调器(中山)有限公司 | Power model startup self-detection method, device and storage medium |
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| CN109951908A (en) * | 2017-12-21 | 2019-06-28 | 佛山市顺德区美的电热电器制造有限公司 | The drive control circuit and drive control method of electromagnetic heating system and its IGBT |
| CN109951908B (en) * | 2017-12-21 | 2021-04-20 | 佛山市顺德区美的电热电器制造有限公司 | Electromagnetic heating system and IGBT drive control circuit and drive control method thereof |
| CN113625145A (en) * | 2021-08-12 | 2021-11-09 | 合肥恒钧检测技术有限公司 | Equipment and method for testing optocoupler |
| CN113625145B (en) * | 2021-08-12 | 2024-05-28 | 恒钧检测技术有限公司 | Device and method for testing optocoupler |
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Application publication date: 20150715 |