CN110492727A - A kind of driving circuit for IGBT series average-voltage - Google Patents

Abstract

The present invention provides a kind of driving circuit for IGBT series average-voltage, belongs to power electronics field.The drive control of series IGBT had not only may be implemented in the driving circuit, but also can realize Pressure and Control in IGBT series operation.A driver and several resistance, capacitor, zener diode is used only in driving circuit, make it have the ability of the driving concatenated IGBT of any amount, avoid complicated powerup issue, completely eliminate the nonsynchronous problem of series IGBT driving signal, overcome the limitation of balancing capacitance size, low-frequency oscillation is slowed down, provides better turn-off characteristic for IGBT.Active clamp circuit is used simultaneously, can be effectively reduced the due to voltage spikes of IGBT when off, and there is good equalizing effect.

Description

A kind of driving circuit for IGBT series average-voltage

Technical field

The present invention relates to power electronics fields, and in particular to a kind of driving circuit for IGBT series average-voltage.

Background technique

With the development of society, the demand to the energy is increasing, but the increasingly deficient and environmental pollution of fossil energy sources The problems such as, the sustainable development in social progress and the world is restrict, therefore new energy was increasingly becoming and grinds both at home and abroad in recent years The hot spot studied carefully.China is wind energy luminous energy deposit big country, and the potentiality of wind energy luminous energy development and utilization are very large.So renewable energy Extensive access of the source to smart grid is one of project most popular at present.Countries in the world smart grid demonstration project and show The construction in model city is in full swing on a large scale, main means of the modern power electronics technology as transformation of electrical energy, As one of smart grid core technology.

More stringent requirements are proposed for the range of nominal tension of the development of power electronics to power electronic devices.IGBT is good with its Good switch performance application prospect is boundless.However, the maximum rated voltage of existing IGBT only has 6.5kV.The series connection of IGBT Higher rated operational voltage, the most important can be not only obtained in the application, it is also possible to obtain under identical voltage level Better switch performance.But due to external various reasons, the series voltage of IGBT is unbalanced to lead to local overvoltage, thus meeting Single tube is caused to burn, the problem of this is current IGBT series connection urgent need to resolve.

For the direct series equalization technologies of IGBT, domestic and international each scholar proposes the different mode of a large amount of outstanding thinkings, Generally speaking, two classes: load-side control and grid control can be divided into.Load-side control be passive snubber technology, be Parallel connection one group of RC or RCD in IGBT pipe both ends reduces the end IGBT voltage by increasing IGBT collector-emitter capacity value DV/dt, to reduce IGBT in the peak voltage for being switched on or off the moment.But when due to the switching delay and hangover of high tension apparatus Between it is longer, the dispersibility of multiple drive power signal is larger when additional series IGBT, and dynamic control effect is unobvious, the control time compared with Long, loss is larger, and control effect is unsatisfactory.

Grid control technology is to be indirectly controlled V by the mode of action in the signal source and signal that control grid_CE.From For controlling grid signal source, main control method is by the way that a reference voltage V is arranged_REF, the V of more single IGBT_CE And V_REFDifference, by signal feed back to control circuit, to reach the control to grid.Wherein most typically P.R.Palmer A kind of active control method of non-grid current injection mode of equal propositions, referred to as active voltage control, by comparing V_CEWith give Fixed V_REFDifference generate control signal, to reach the control to grid signal.Dynamic voltage balancing of this design to series IGBT It is highly beneficial, each switching tube V in dynamic process_CEThe same reference signal is all followed, equalizing effect is preferable, but due to being added Independent reference voltage, number and simulation mixing control circuit, circuit more bulky complex are connected in high-power IGBT Application environment under, reliability is not high.There are also one is the master & slave controls that Agostino Galluzzo et al. was proposed in 2001 Mode as the reference voltage with the voltage of one of IGBT is selectively implanted or draws grid current by comparing, To the voltage change ratio of control switch transient state, and then reach balanced.The circuit include the end IGBT voltage pressure sampling circuit, The generation circuit and main driving circuit of amplifier comparison circuit and pulse control electric current.Since reference voltage chooses one of them The voltage of IGBT, and be not introduced into individual reference voltage, circuit complexity reduce, but also due to control circuit is excessively complicated, So that the reliability of circuit reduces.

Existing method for equalizing voltage has the shortcomings that following items are universal: (1) circuit design and control are complicated；(2) auxiliary member Number of devices excessively causes reliability to reduce；(3) it needs using high speed, highly sensitive component；(4) it needs using buffering capacitor Or voltage clamp circuit come prevent IGBT the tail current stage occur voltage unevenness；(5) to the variation of temperature and load current It is too sensitive；(6) electromagnetic interference situation is serious.

Currently, having some patents about IGBT series equalization technologies, having as described in CN10220800A both at home and abroad Flow the adaptive IGBT series average-voltage circuit of defencive function；As described in CN101728952A based on ARM microprocessor control IGBT series circuit；Optimal turn-off time based on global controller and local control as described in CN104779780A and most The IGBT series average-voltage circuit of excellent service time control.Above-mentioned equalizer circuit is all in the presence of the drawback that structure is complicated, device is cumbersome.

Summary of the invention

It is an object of the invention to overcome the above-mentioned prior art, a kind of driving circuit of series IGBT is provided, The drive control of series IGBT had not only may be implemented in the circuit, but also can reduce due to voltage spikes in IGBT series operation, realize Press effect.

In order to achieve the above objectives, the technical solution adopted by the present invention is that:

A kind of driving circuit for IGBT series average-voltage characterized by comprising n active clamp circuit, n IGBT pipe S₁.....S_n, n balancing capacitance C₁.....C_n, n balance resistance R_s1.....R_sn, 2n+2 zener diode: D_1a、D_1b.....D_na、D_nbAnd D_a、D_b, 1 driver, 1 primary gate driving resistance R_g, n secondary grid driving resistance R₁.....R_n, 1 Schottky diode D_g；The collector of previous IGBT pipe is connected with the emitter of the latter IGBT pipe； I-th of IGBT pipe S_iGrid and emitter between pass through the zener diode D of two differential concatenations_ia,D_ibIt is connected；I-th Secondary grid drives resistance R_iOne end and i-th of IGBT pipe S_iGrid be connected, previous secondary grid driving resistance it is another A balance resistance in parallel and a balancing capacitance are distinguished between one end and the other end of the latter secondary grid driving resistance；The N IGBT pipe S_nEmitter and two differential concatenations zener diode D_a、D_bIt is connected, n-th of secondary grid drives resistance R_nThe other end and differential concatenation two zener diode D_a、D_bFree end between respectively and be connected to a balance resistance R_snWith a balancing capacitance C_n；The driving signal output end of driver passes through primary gate driving resistance R_gWith the 1st secondary grid Pole drives resistance R₁The other end be connected, drive the ground terminal and the 1st IGBT pipe S of core₁Emitter be connected, primary grid Pole drives resistance R_gOne Schottky diode D of inverse parallel_g；N >=3,1≤i≤n, and n and i are natural number.

It include 1 for i-th of active clamp circuit in a kind of above-mentioned driving circuit for IGBT series average-voltage Fast recovery diode D_i1, 1 current-limiting resistance R_i1, 1 discharge resistance R_i2, 2 Transient Suppression Diode Z_i1And Z_i2, 1 capacitor C_i1；I-th of active clamp circuit and i-th of IGBT pipe S_iOn-link mode (OLM) it is as follows: the collector of IGBT pipe and fast restore two poles Pipe D_i1Anode be connected, fast recovery diode D_i1Cathode and current-limiting resistance R_i1One end be connected, current-limiting resistance R_i1It is another One end respectively with Transient Suppression Diode Z_i2Cathode, capacitor C_i1One end, discharge resistance R_i2One end be connected, transient state suppression Diode Z processed_i2Anode, capacitor C_i1The other end, discharge resistance R_i2The other end respectively with Transient Suppression Diode Z_i1Yin Pole is connected, Transient Suppression Diode Z_i1Anode be connected with the grid of IGBT pipe；N >=3,1≤i≤n, and n and i are certainly So number.

The advantages and positive effects of the present invention are:

1, due to the adoption of the above technical scheme, a driver is used only in driving circuit, just has driving any amount string The ability of the IGBT of connection completely eliminates the nonsynchronous problem of series IGBT driving signal, overcomes the limit of balancing capacitance size System, slows down low-frequency oscillation, provides better turn-off characteristic for IGBT；Further, since active clamp circuit has been used, so energy It is enough effectively reduced the due to voltage spikes of IGBT when off, there is good equalizing effect；

2, a kind of driving circuit for IGBT series average-voltage provided by the invention, circuit structure is simple, reliable, parts number Amount is few, and IGBT can be made to work in higher switching frequency, generate less power loss, at low cost, and occupied space size Small, suitable for middle pressure serial module structure subelement application.

Detailed description of the invention

Fig. 1 is the circuit diagram in 2 tunnel of the present invention circuit.

Fig. 2 be the present invention relates to the considerations of parasitic inductance when opening using latter two series IGBT of driving circuit of the invention Logical transient collector-emitter voltage waveform diagram.

Fig. 3 be the present invention relates to the considerations of parasitic inductance when using latter two series IGBT of driving circuit of the invention pass Disconnected transient collector-emitter voltage waveform diagram.

Fig. 4 is the circuit diagram in the road N circuit of the present invention.

Specific embodiment

The present invention is understood and implemented for the ease of those of ordinary skill in the art, and the present invention is done into one with reference to the accompanying drawing Step detailed description, it should be understood that example described herein is merely to illustrate and explain the present invention, and is not used to limit this hair It is bright.

Assuming that n=2, that is, 2 IGBT series operations are used, loaded as resistance sense, circuit diagram is as shown in Figure 1.Wherein, described Driving circuit example includes: 2 active clamp circuits, 2 IGBT pipe S₁And S₂, 2 balancing capacitance C₁And C₂, 2 balance resistances R_s1And R_s2, 4+2 zener diode: D_1a、D_1b、D_2a、D_2bAnd D_a、D_b, 1 driver, 1 primary gate driving resistance R_g, 2 A secondary grid drives resistance R₁And R₂, 1 Schottky diode D_g.Include: for each active clamp circuit example 1 fast recovery diode D_i1, 1 current-limiting resistance R_i1, 1 discharge resistance R_i2, 2 Transient Suppression Diodes: Z_i1And Z_i2, 1 Capacitor C_i1(i=1 or i=2).

Specific circuit link topology is as follows:

IGBTS₁Collector and IGBTS₂Emitter be connected；IGBTS₁Grid and emitter between pass through two The zener diode D of differential concatenation_1a,D_1bIt is connected；The driving signal output end of driver passes through primary gate driving resistance R_g Resistance R is driven with secondary grid₁It is connected to node A₁, drive the ground terminal and IGBTS of core₁Emitter be connected, primary grid Drive resistance R_gOne Schottky diode D of inverse parallel_g；For circuit 1, the pin connection order of each component is as follows: resistance R₂-IGBTS₂Grid-zener diode D_2aAnode-zener diode D_2aCathode-zener diode D_2bCathode-pressure stabilizing Diode D_2bAnode-IGBTS₂Emitter-fast recovery diode D₁₁Anode-fast recovery diode D₁₁Cathode-resistance R₁₁Transient Suppression Diode Z₁₂Cathode-Transient Suppression Diode Z₁₂Anode-Transient Suppression Diode Z₁₁Cathode-transient state Inhibit diode Z₁₁Anode-IGBTS₁Grid-resistance R₁Capacitor C₁Resistance R₂；In addition, capacitor C₁₁, resistance R₁₂Respectively with Transient Suppression Diode Z₁₂Parallel connection, resistance R_s1With capacitor C₁It is in parallel；For circuit 2, the pin connection order of each component is as follows: Zener diode D_aAnode-zener diode D_aCathode-zener diode D_bCathode-zener diode D_bAnode- IGBTS₂Collector-fast recovery diode D₂₁Anode-fast recovery diode D₂₁Cathode-resistance R₂₁Transient state inhibits two poles Pipe Z₂₂Cathode-Transient Suppression Diode Z₂₂Anode-Transient Suppression Diode Z₂₁Cathode-Transient Suppression Diode Z₂₁'s Anode-IGBTS₂Grid-resistance R₂Capacitor C₂Zener diode D_aAnode；In addition, capacitor C₂₁, resistance R₂₂Respectively with wink State inhibits diode Z₂₂Parallel connection, resistance R_s2With capacitor C₂It is in parallel；Hinder one sustained diode of inductive load inverse parallel, V_dcIt is straight Flow busbar voltage；L_sFor bus stray inductance.

The opening process principle of proposed circuit is as shown in Fig. 2, be divided into three parts.

The circuit 1 and circuit 2 according to shown in Fig. 1 can be write out if ignoring parasitic inductance by Kirchhoff's second law Following voltage equation:

Circuit 1:V_A1B1+V_C1=V_ce1+V_A2B2 (1)

Circuit 2:V_A2B2+V_C2=V_ce2+V_Z (2)

Based on above-mentioned equation, the course of work of driving circuit of the present invention the following steps are included:

(1) 1 (t of stage₀~t₁): when gate drive signal is switched to timing, opening process is in t₀Moment starts.At this moment, V_A1B1It rises to close to 15V, and the voltage of balancing capacitance will not quickly change, in addition, S₂Gate-emitter voltage it is still low In threshold voltage.According to formula (1), V_ce1Incrementss and V_A1B1It is equal.According to formula (2), V_ce2Reduction amount be equal to V_ZIncrementss (V_Z=V_Da+V_Db).By considering external circuit, V_ZIncrementss be equal to V_A1B1Incrementss.In this stage, S₁Grid-hair Emitter voltage rises to threshold voltage.

(2) 2 (t of stage₁~t₂): in t₁Moment works as S₁Gate-emitter voltage when reaching threshold voltage, S₁Impedance Reduce, corresponding collector emitter voltage V_ce1Also reduce.According to formula (1), V_ce1Reduction lead to V_A2B2Increase, thus Cause S₂Gate-emitter voltage be more than threshold voltage.According to formula (2), due to the voltage V of zener diode_ZIt is constant in 15V, So V_A2B2Increase will lead to V_ce2Increase.In this stage, S₂Gate-emitter voltage rise to Miller platform voltage, According to the transfer characteristic of device, load current commutates to IGBT, and no current flows through balancing capacitance at this time.

(3) 3 (t of stage₂~t₃): in this stage, load current commutation is completed, and IGBT is in active area, the grid of each IGBT Pole-emitter voltage is Miller voltage value, which is determined by the mutual conductance and load current of device, the current collection of each IGBT Pole-emitter voltage, which is almost started simultaneously at, to be begun to decline from steady-state value to saturation voltage drop, voltage overshoot does not occur, so device Dynamic voltage balancing be achieved in this stage.Because in this stage V_A1B1、V_A2B2And V_ZIt is all constant, so formula (1)~(2) are right The derivative of time can characterize the phenomenon that dynamic voltage balancing, such as formula (3)~(5):

Since the electric current for flowing through each balancing capacitance is equal, and the capacitance of each balancing capacitance is identical, it is possible to release

In this stage, balancing capacitance C₁And C₂It plays an important role, upper layer IGBT device S₂Required grid is opened completely Charge is by the balancing capacitance C in Fig. 1₁And C₂Electric discharge realize.The electric current for being injected into every level-one IGBT grid arises directly from IGBT open transient state during balancing capacitance electric current.The collector emitter voltage change rate dV/dt of IGBT is directly controlled by flat Weigh capacitor's capacity and grid resistance resistance value.

(4) 4 (t of stage₃Later): in t₃At the moment, opening transient process terminates.Later, the gate-emitter electricity of two IGBT Pressure continues slowly to rise, and device is finally brought into the saturation region that can be used gate charge to be influenced by it, and device both end voltage is lower On-state voltage drop, and S₂Gate-emitter voltage compare S always₁The low S of gate-emitter voltage₁On-state voltage drop.

The turn off process principle of the circuit is as shown in figure 3, be divided into three parts.Formula (1) and formula (2) are still set up.

(1) 1 (t of stage₀~t₁): in t₀At the moment, two IGBT are all in saturation region.S₁Gate-emitter voltage be equal to Gate drive power voltage V_CC, S₂Gate-emitter voltage it is more slightly lower.When grid voltage is from V_CCBecome V_EEWhen, it can make V_A1B1、V_A2B2Reduce suddenly, the grid capacitance of two IGBT is discharged simultaneously.

(2) 2 (t of stage₁~t₂): reach t₁When the moment, S₂Gate-emitter voltage be down to Miller platform voltage value, lead Cause V_ce2Start to increase, and V_ce1It remains unchanged.According to formula (2), due to the voltage V of zener diode_ZIt is constant in 15V, so V_ce2 Increase will lead to V_A2B2Increase, therefore S₂Discharge current limited, lead to V_ce2Climbing speed be reduced.In t₂When It carves, S₁Gate-emitter voltage be down to Miller platform voltage value, two IGBT enter active area.

(3) 3 (t of stage₂~t₃): in this stage, V_ce1And V_ce2Start simultaneously at rising, and balancing capacitance C in this stage₁With C₂Sufficiently collector emitter voltage change rate in control dynamic process.Work as V_ce1And V_ce2Less than V_n1When, clamp circuit voltage by Transient state inhibits diode Z_n1It undertakes, clamp circuit does not work, V_ce1And V_ce2Voltage value is barely affected and normal rapid increase.

(4) 4 (t of stage₃~t₄): in this stage, V_ce1And V_ce2Reach the half close to DC bus-bar voltage, load current It commutates from IGBT to freewheeling diode, the collector current of IGBT sharply drops to 0, S₁And S₂Gate-emitter voltage be down to Threshold voltage.V_ce1And V_ce2Greater than V_n1, transient state inhibition diode Z_n1Breakdown, which passes through capacitor C_n1With resistance R_n1, by In shunt capacitance C_n1It is equivalent to increase the parasitic miller capacitance of IGBT, therefore the rate of rise of collector emitter voltage value is bright It is aobvious to reduce；Meanwhile clamp circuit electric current passes through diode D_n1Grid is flowed into, so that the discharge current of grid is reduced, to drop The turn-off speed of low IGBT.

(5) 5 (t of stage₄~t₅): in this stage, S₁Gate-emitter voltage continue to decline to gate drive power electricity Press V_EE, and due to S₂Grid capacitance pass through high value balance resistance R_s1The speed of electric discharge is very slow, so S₂Gate-emitter Voltage can maintain, variation unconspicuous level more slightly lower than its threshold voltage in a long time.Work as V_ce1And V_ce2Rise to two Grade clamp value, i.e. V_ce1And V_ce2Greater than V_n1+V_n2When, two-stage transient state inhibition diode is breakdown and maintenance voltage is constant, V_ce1 And V_ce2On voltage ascending amount by resistance R_n1It undertakes.Due to R_n1Typically small, the electric current of the stage clamp circuit is compared to rank Section 4 increases, to further slow down shutdown voltage rising, clamp current makes V after reaching dynamic equilibrium with voltage rising_ce1 And V_ce2It is clamped to and compares V_n1+V_n2More slightly higher value.

(6) 6 (t of stage₅Later): after due to voltage spikes oscillatory process terminates, V_ce1And V_ce2Drop quickly to level-one pincers Place value is hereinafter, capacitor C_n1By resistance R_n2Realize repid discharge, clamp circuit restores to stablize off state.It connects at this time IGBT has reached shutdown stable state, if the leakage current of device is balance, according to formula (1) and formula (2), can release V_ce1And V_ce2 Meet following formula relationship:

V_ce1-V_ce2=V_C1-V_C2+V_Z+V_A1B1-2V_A2B2 (7)

V in many cases,_A2B2Only slightly below threshold voltage V_th, V_ZPressure stabilizing is in -15V, so can release

V_ce1-V_ce2≈V_C1-V_C2-30-2V_th (8)

The partial pressure of two balancing capacitances depends mainly on the resistance value ratio of two balance resistances, therefore S when shutdown stable state₁And S₂ End voltage be entirely controllable.It is therefore seen that the driving circuit invented ensure that 2 IGBT service times and pass Temporal consistency of breaking and while make each IGBT reliably open, turn off, also meet the dynamics of 2 series IGBTs with it is quiet State presses demand, to realize that series IGBT is run safe and efficiently.

Finally it should be noted that: one embodiment of the present invention has been described in detail above, but the content is only For presently preferred embodiments of the present invention, should not be considered as limiting the scope of the invention.It is all according to the present patent application range institute Modification, supplement and improvement of work etc., should still be within the scope of the patent of the present invention.Do not make in this specification in detail The content of description belongs to the prior art well known to professional and technical personnel in the field.

Claims (2)

1. a kind of driving circuit for IGBT series average-voltage characterized by comprising n active clamp circuit, n IGBT Pipe S₁…..S_n, n balancing capacitance C₁…..C_n, n balance resistance R_s1…..R_sn, 2n+2 zener diode: D_1a、D_1b… ..D_na、D_nbAnd D_a、D_b, 1 driver, 1 primary gate driving resistance R_g, n secondary grid driving resistance R₁…..R_n, 1 Schottky diode D_g；The collector of previous IGBT pipe is connected with the emitter of the latter IGBT pipe；I-th of IGBT pipe S_i Grid and emitter between pass through the zener diode D of two differential concatenations_ia,D_ibIt is connected；I-th of secondary grid driving Resistance R_iOne end and i-th of IGBT pipe S_iGrid be connected, the other end and the latter of previous secondary grid driving resistance Secondary grid, which drives, distinguishes a balance resistance in parallel and a balancing capacitance between the other end of resistance；N-th of IGBT pipe S_n Emitter and two differential concatenations zener diode D_a、D_bIt is connected, n-th of secondary grid drives resistance R_nThe other end With two zener diode D of differential concatenation_a、D_bFree end between respectively and be connected to a balance resistance R_snIt is flat with one Weigh capacitor C_n；The driving signal output end of driver passes through primary gate driving resistance R_gResistance R is driven with the 1st secondary grid₁ The other end be connected, drive the ground terminal and the 1st IGBT pipe S of core₁Emitter be connected, primary gate driving resistance R_g One Schottky diode D of inverse parallel_g；N >=3,1≤i≤n, and n and i are natural number.

2. a kind of driving circuit for IGBT series average-voltage according to claim 1, which is characterized in that for i-th Active clamp circuit includes 1 fast recovery diode D_i1, 1 current-limiting resistance R_i1, 1 discharge resistance R_i2, 2 transient states inhibit two Pole pipe Z_i1And Z_i2, 1 capacitor C_i1；I-th of active clamp circuit and i-th of IGBT pipe S_iOn-link mode (OLM) it is as follows: IGBT pipe Collector and fast recovery diode D_i1Anode be connected, fast recovery diode D_i1Cathode and current-limiting resistance R_i1One end phase Connection, current-limiting resistance R_i1The other end respectively with Transient Suppression Diode Z_i2Cathode, capacitor C_i1One end, discharge resistance R_i2 One end be connected, Transient Suppression Diode Z_i2Anode, capacitor C_i1The other end, discharge resistance R_i2The other end respectively with Transient Suppression Diode Z_i1Cathode be connected, Transient Suppression Diode Z_i1Anode be connected with the grid of IGBT pipe；n≥ 3,1≤i≤n, and n and i are natural number.