CN108880515A - The control method and device of IGBT ON-OFF control circuit - Google Patents

Abstract

The invention discloses a kind of control methods of IGBT ON-OFF control circuit, including:The detection voltage on the emitter to the parasitic inductance between the corresponding lead terminal of the emitter of the IGBT module is obtained in real time；The detection voltage is compared with preset threshold；IGBT grid current is exported according to comparison result and controls signal, by the detection voltage stabilization in the preset threshold.The variable condition that the di/dt value of the IGBT module can be monitored in real time by monitoring the detection voltage, realize the dynamic process of di/dt during monitoring the IGBT module switch, and then it realizes through the detection voltage and controls the grid current for inputting the IGBT module, to optimize the turn-off speed of the IGBT module, it is avoided that over-voltage is failed, optimizes turn-off power loss and conduction loss.

Description

Control method and device for IGBT switch control circuit

technical field

The invention relates to the field of electronic technology, in particular to a control method and device for an IGBT switch control circuit.

Background technique

The full name of IGBT is insulated gate bipolar transistor. IGBT is an important component of electrical devices. It is a voltage-controlled power transistor. It can be regarded as a high-power version of CMOS tube. It is a combination of MOSFET and BJT. Its characteristics The switching frequency is high, and the main applications in the home are such as inverter air conditioners, induction cookers, microwave ovens, and active pfc and UPS for computer power supplies. Industrial applications are mainly used for various motor drives. In terms of function, IGBT is a circuit switch, which is used in high voltages with voltages of tens to hundreds of volts and currents of tens to hundreds of amperes. If the voltage between its collector and emitter exceeds its maximum withstand voltage value, electric field breakdown will occur and the IGBT will fail. Therefore, there must be overvoltage protection measures during the use of the IGBT. When the IGBT turns off the device, its The voltage at both ends is the sum of the DC bus voltage and the voltage generated by the parasitic inductance of the commutation circuit. The bus voltage generally does not fluctuate, and the voltage generated by the parasitic inductance of the commutation circuit will increase with the increase of the main current.

When the IGBT is turned off, the grid-emitter voltage is easily disturbed by the IGBT and circuit parasitic parameters, causing the device to be mis-conducted. To prevent this phenomenon, a resistor can be connected in parallel between the grid-emitter. In addition, in order to prevent high-voltage spikes in the gate drive circuit in practical applications, it is best to connect two reverse-series zener diodes in parallel between the gate and the emitter, and their regulated voltage values should be the same as the positive and negative gate voltages. At present, the control of IGBT overvoltage is generally by directly detecting the voltage Vce of the collector and emitter of the IGBT tube Q1 during the turn-off period, that is, directly connecting a high-voltage diode or multiple low-voltage diodes in series between the collector and the drive terminal, see Figure 1, two diodes D1 and D2 are connected in series at the collector and the driving end. Once the collector and emitter voltage Vce exceeds the reverse breakdown voltage of the diode, a negative feedback current is carried out at the driving end, thereby connecting the collector and the emitter The voltage control between the poles is clamped at a certain value. If Vce is lower than this value, the circuit will not work, and the excessive peak voltage generated by the parasitic inductance of the loop cannot be avoided, and unnecessary heat will be generated when the switching loss is large. , the negative feedback circuit of the IGBT cannot be controlled during the turn-on period, so the optimization of the turn-on process of the IGBT cannot be controlled.

Contents of the invention

The technical problem to be solved by the present invention is to provide a control method for an IGBT switch control circuit, which can avoid overvoltage failure, optimize the turn-off speed and thereby optimize the turn-off loss.

In the first aspect, the present invention proposes a control method of an IGBT switch control circuit, comprising:

Acquire in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter;

comparing the detection voltage with a preset threshold;

Outputting an IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold.

In the first possible implementation manner of the first aspect, the outputting the IGBT gate voltage according to the comparison result

A flow control signal to stabilize the detection voltage at the preset threshold includes:

output an IGBT gate current increase signal when the detection voltage is less than the preset threshold, and output an IGBT gate current decrease signal when the detection voltage is greater than the preset threshold, so as to stabilize the detection voltage at The preset threshold.

In a second possible implementation manner of the first aspect, the preset threshold includes: a first threshold and a second threshold, wherein the first threshold is greater than the second threshold;

Then the outputting the IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold includes:

When the detection voltage is greater than the first threshold, output an IGBT gate current decrease signal, and when the detection voltage is less than the second threshold, output an IGBT gate current increase signal to reduce the detection voltage stable between the first threshold and the second threshold.

In combination with the first possible implementation of the first aspect and the second possible implementation of the first aspect, in the third possible implementation of the first aspect, the output IGBT gate current reduction signal is specifically to the resistor The adjustment unit outputs a resistance increase signal, so that the gate drive resistance on the IGBT module increases to reduce the gate current of the IGBT module; the output IGBT gate current increase signal is specifically output to the resistance adjustment unit The resistance reduction signal causes the gate drive resistance on the IGBT module to decrease to increase the gate current of the IGBT module.

In combination with the first possible implementation of the first aspect and the second possible implementation of the first aspect, in the fourth possible implementation of the first aspect, the outputting the IGBT gate current reduction signal is specifically to bidirectional The power supply outputs a current extraction signal, so that the bidirectional power supply draws current from the gate of the IGBT module; the output IGBT gate current increase signal is specifically to output a current injection signal to the bidirectional power supply, so that the bidirectional power supply draws current from the gate of the IGBT module The gate injection current of the IGBT module.

In the second aspect, the present invention provides a control device for an IGBT switch control circuit, which is characterized in that it is used to control the switching process of the IGBT module, including:

A detection voltage acquisition module, configured to obtain in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter;

A comparison module, configured to compare the detection voltage with a preset threshold;

The signal output module is used to output the IGBT gate current control signal according to the comparison result, so as to stabilize the detection voltage at the preset threshold.

In a first possible implementation manner of the second aspect, the signal output module includes:

output an IGBT gate current increase signal when the detection voltage is less than the preset threshold, and output an IGBT gate current decrease signal when the detection voltage is greater than the preset threshold, so as to stabilize the detection voltage at The preset threshold.

In a second possible implementation manner of the second aspect, the preset threshold includes: a first threshold and a second threshold, wherein the first threshold is greater than the second threshold;

Then the signal output module includes:

When the detection voltage is greater than the first threshold, output an IGBT gate current decrease signal, and when the detection voltage is less than the second threshold, output an IGBT gate current increase signal to reduce the detection voltage stable between the first threshold and the second threshold.

In combination with the first possible implementation of the second aspect and the second possible implementation of the second aspect, in the third possible implementation of the second aspect, the output IGBT gate current reduction signal is specifically to the resistor The adjustment unit outputs a resistance increase signal, so that the gate drive resistance on the IGBT module increases to reduce the gate current of the IGBT module; the output IGBT gate current increase signal is specifically output to the resistance adjustment unit The resistance reduction signal causes the gate drive resistance on the IGBT module to decrease to increase the gate current of the IGBT module.

In combination with the first possible implementation of the second aspect and the second possible implementation of the second aspect, in the fourth possible implementation of the second aspect, the outputting the IGBT gate current reduction signal is specifically to bidirectional The power supply outputs a current extraction signal, so that the bidirectional power supply draws current from the gate of the IGBT module; the output IGBT gate current increase signal is specifically to output a current injection signal to the bidirectional power supply, so that the bidirectional power supply draws current from the gate of the IGBT module The gate injection current of the IGBT module.

Implement the present invention, have following beneficial effect:

In the process of controlling the switching of the IGBT module, by obtaining in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter, and comparing the detection voltage with a preset threshold; Output the IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold, and monitor the change state of the di/dt value of the IGBT module in real time by monitoring the detection voltage, that is, realize Monitoring the dynamic process of di/dt during the switching period of the IGBT module, and then controlling the gate current input to the IGBT module through the detection voltage, thereby optimizing the turn-off speed of the IGBT module and avoiding overvoltage Ineffective, optimize the turn-off loss and conduction loss, and solve the problem that in the prior art, Vce cannot control the change of di/dt below the clamping voltage point and cannot control di/dt during the turn-on period, so that the IGBT turn-on process cannot be controlled to the maximum problem of optimization.

Description of drawings

FIG. 1 is a schematic diagram of an existing IGBT overvoltage control;

Fig. 2 is the flow block diagram of the control method of IGBT switch control circuit provided by the present invention;

Fig. 3 is the IGBT module lead terminal circuit diagram provided by the present invention;

Fig. 4 is the circuit schematic diagram of an application circuit of the IGBT switch control circuit provided by the present invention;

Fig. 5 is the circuit schematic diagram of two application circuits of the IGBT switch control circuit provided by the present invention;

FIG. 6 is a schematic structural diagram of a control device for an IGBT switch control circuit provided by the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

Referring to FIG. 2 , it is a schematic block diagram of the flow of the control method of the IGBT switch control circuit provided by the present invention. A control method for an IGBT switch control circuit, used to control the switching process of an IGBT module, comprising:

S11. Obtain in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter;

It should be noted that the lead terminal is a terminal with external wiring, that is, the terminal of the external wiring corresponding to the emitter of the IGBT module. Referring to FIG. 3, for the upper tube Q1, the lead terminal is an AC-terminal, That is, the parasitic inductance generated between the emitter and the AC output terminal. For the lower transistor Q2, the lead terminal is a DC-terminal, that is, the parasitic inductance is generated between the emitter and the negative bus terminal.

It should be noted that the parasitic inductance of the emitter of the IGBT not only acts on the main current flowing through the circuit, but also exists in the drive circuit at the same time, so the induced electromotive force not only affects the switching loss from the perspective of increasing or decreasing the tube voltage, but also from the perspective of increasing or decreasing the gate drive. The voltage angle affects the switching losses, and it is not difficult to see intuitively that the benefits in this area are more prominent due to the low gate drive voltage rating. During the turn-off period, the following relationship exists: Among them, U _ge is the actual voltage of the gate, U _drive is the voltage on the pin applied by the drive circuit, L _e is the parasitic inductance of the emitter, is the main collector to emitter current during turn-off. The main current quickly drops on the parasitic inductance of the emitter, and the induced voltage is positively superimposed on the gate of the device during the turn-off period of the IGBT, which slows down the downward trend of the gate voltage that should have dropped, and further delays the turn-off process. In this way, the voltage of the emitter inductance acts from the gate drive circuit to prolong the turn-off tube voltage and current overlap time, and increase the turn-off loss. During the conduction period, the current on the parasitic inductance of the IGBT module rises rapidly, and the direction of the induced electromotive force is equivalent to reducing the driving voltage: During the turn-on period, the faster the gate voltage rises to the saturated conduction value, the shorter the overlap time of the turn-on tube voltage and current is. In this process, the gate voltage is reduced, the turn-on speed is reduced, and the turn-on voltage and current overlap time is prolonged. , the effect on the turn-on loss is also an increase.

In the embodiment of the present invention, the switching loss of the IGBT module is related to the turn-on speed and turn-off speed of the IGBT module, and controlling the value of di/dt can control the turn-on speed and turn-off speed of the IGBT module, Therefore, the switching loss of the IGBT module is optimized, and the performance of the IGBT module is improved. By controlling the drop speed of di/dt to avoid the excessive peak voltage generated by the parasitic inductance of the loop, the safety of the IGBT module is guaranteed. Reasonable control of di/dt can make the IGBT module work in the best state, because too fast If the voltage peak is high, if it is too slow, the switching loss will be large and unnecessary heat will be generated.

In the embodiment of the present invention, although the parasitic inductance on the IGBT module is small, since the di/dt of the IGBT module during switching is relatively large, the voltage U=di/dt*L generated on the parasitic inductance will be large, the detection voltage is U=di/dt*L.

It should be noted that the parasitic inductance of the IGBT module is different for each IGBT, and the detection voltage can be obtained by directly detecting the voltage on the parasitic inductance of the IGBT module. For example, the voltage on the parasitic inductance of the IGBT module can be detected and acquired by a voltmeter, a voltage detection circuit, a voltage sensor, and the like.

It should be noted that, after obtaining the detection voltage, the di/dt value on the IGBT module can be obtained through the detection voltage U=di/dt*L and the parasitic inductance on the IGBT module, that is, the The detection voltage indirectly reflects the di/dt value on the IGBT module, and the di/dt value is related to the gate current. The larger the gate current, the faster the switching speed, so the di/dt value is higher. Larger, the greater the voltage peak, the smaller the switching loss at this time, otherwise, the turn-on is slow, the peak voltage is small, and the switching loss is large.

S12. Comparing the detected voltage with a preset threshold;

In this embodiment, the preset threshold is designed according to the heat dissipation of the system and the peak voltage of the IGBT module tested. When the peak voltage cannot exceed the withstand voltage value of the IGBT module, the threshold It is required that the di/dt value of the IGBT module does not exceed the specified value of the IGBT module, and the temperature rise caused by the loss of the IGBT module does not exceed the specified value of the IGBT module. The preset threshold is related to the system It is related to the design parameters, such as the parasitic inductance of the power loop, the IGBT voltage derating point designed by the designer, etc., which are not specifically limited in the present invention.

S13. Outputting an IGBT gate current control signal according to the comparison result, so as to stabilize the detection voltage at the preset threshold.

In this embodiment, mainly by controlling the gate current input to the IGBT module, because the gate current is related to the di/dt value, when the detection voltage is stabilized at the preset threshold, the The di/dt value of the IGBT module is within the preset range, and then by controlling the di/dt value of the IGBT module within the preset range, the switching speed is controlled within the preset condition, and by controlling the switching speed , the peak voltage and switching loss of the IGBT module can be controlled.

In this embodiment, the switching speed of the IGBT module is controlled by controlling the gate current input to the IGBT module, and the speed of controlling the switching can be approximately linearly equivalent to charging the gate capacitance of the IGBT module. It is a non-linear relationship with the temperature and the bus voltage of the system. The charging and discharging time is also the corresponding switching time, t=Q/Ig, where Q is the gate charge of the IGBT and is a parameter of the IGBT module.

Implementing this embodiment has the following beneficial effects:

In the process of controlling the switching of the IGBT module, by obtaining in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter, and comparing the detection voltage with a preset threshold; Output the IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold, and monitor the change state of the di/dt value of the IGBT module in real time by monitoring the detection voltage, that is, realize Monitoring the dynamic process of di/dt during the switching period of the IGBT module, and then controlling the gate current input to the IGBT module through the detection voltage, thereby optimizing the turn-off speed of the IGBT module and avoiding overvoltage Failure, optimize the turn-off loss and conduction loss, by using the IGBT's own parasitic inductance, without adding a special current detection device or inductance, real-time monitoring of the switching dynamic process of the IGBT, real-time adjustment of the gate current to control the switching speed of the IGBT.

Embodiment two

Preferably, the outputting the IGBT gate current control signal according to the comparison result to stabilize the detection voltage within a preset range includes:

Outputting an IGBT gate current decrease signal when the detection voltage is less than the preset threshold, and outputting an IGBT gate current increase signal when the detection voltage is greater than the preset threshold, so as to stabilize the detection voltage at The preset threshold.

In this embodiment, the detection voltage may be stabilized within a preset range of the preset threshold, which is not specifically limited in the present invention.

In this embodiment, the preset threshold is designed according to that the di/dt value of the IGBT module cannot exceed the limit value specified in the IGBT specification, and the temperature rise caused by the switching loss does not exceed the maximum temperature rise of the IGBT.

When the detection voltage is less than the preset threshold, that is, when di/dt*L is small, then di/dt is small, and the turn-on speed of the IGBT module is slow. At this time, the IGBT switching loss is large, which will cause the IGBT temperature High and not running in the best state, there is a risk of overheating, and it is necessary to increase the gate current Ig to speed up the shutdown speed.

When the detection voltage is greater than the preset threshold, that is, di/dt*L is larger, then di/dt is larger, and di/dt*L and the bus voltage are superimposed on the collector and emitter of the IGBT, which may cause To cause the risk of voltage breakdown, it is necessary to reduce the gate current Ig and reduce the turn-off speed.

For the convenience of description, referring to Fig. 4, the working process of the second embodiment of the present invention is described in conjunction with an application circuit of the IGBT switch control circuit. The control method of the IGBT switch control circuit provided by the present invention is not limited to the IGBT switch control Circuit to application circuit:

An application circuit of an IGBT switch control circuit includes resistors R1, R2, R3, R4, R5, a switch tube 1, a switch tube 2, and a gate port G and an emitter port E of an IGBT; wherein, the switch tube 1 and the switch tube 1 The switch tube 2 can be a three-terminal control device such as a triode, a field effect transistor, an IGBT, a thyristor, or a derivative thereof.

Between the emitter E port of the IGBT module and the port DC-terminal, due to the parasitic inductance L inside the IGBT module, the L induced voltage di/dt*L generated by the parasitic inductance L is divided by the resistor R4 and the resistor R5. When the voltage on the parasitic inductance is greater than the preset threshold, that is, the di/dt is too large, the switch 1 is turned on, and the preset threshold is the conduction voltage of the switch 1. When the switching tube 1 is turned on, the switching tube 2 is turned on, and after the switching tube 2 is turned on, the VCC power supply charges the gate G of the IGBT through the switching tube 2 and R2, which is equivalent to charging IGBT gate capacitor charging, this capacitor is a non-linear relationship with the temperature and the bus voltage of the system, the charging and discharging time is also the corresponding switching time, t=Q/Ig, thus reducing the turn-off speed; When the voltage on the parasitic inductance is less than the preset threshold, that is, di/dt is too small, the switch tube 1 is turned off, and the preset threshold is the conduction voltage of the switch tube 1. When the switching tube 1 is turned off, the switching tube 2 is turned off, and after the switching tube 2 is turned off, the VCC power supply does not pass through the switching tube 2 to charge the gate G of the IGBT through R2, which is equivalent to charging the IGBT gate Capacitor discharge, this capacitor is a non-linear relationship with the temperature and the bus voltage of the system, the charging and discharging time is also the corresponding switching time, t=Q/Ig, thus increasing the turn-off speed.

Implementing this embodiment has the following beneficial effects:

Outputting an IGBT gate current decrease signal when the detection voltage is less than the preset threshold, and outputting an IGBT gate current increase signal when the detection voltage is greater than the preset threshold, so as to stabilize the detection voltage at The preset threshold value controls the magnitude of the IGBT gate current by comparing the detection voltage, monitors the switching dynamic process of the IGBT in real time, adjusts the gate current in real time to control the switching speed of the IGBT, and avoids excessive shutdown of the IGBT. Overheating failure caused by voltage spikes and excessive switching time.

Embodiment three

Preferably, the preset threshold includes: a first threshold and a second threshold, wherein the first threshold is greater than the second threshold;

Then the outputting the IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold includes:

When the detection voltage is greater than the first threshold, output an IGBT gate current decrease signal, and when the detection voltage is less than the second threshold, output an IGBT gate current increase signal to reduce the detection voltage stable between the first threshold and the second threshold.

In this embodiment, the first threshold and the second threshold are based on the fact that the di/dt value of the IGBT module cannot exceed the limit value specified in the IGBT specification, and the temperature rise caused by the switching loss does not exceed the IGBT The maximum temperature rise is designed, and by setting two thresholds, the IGBT module can be controlled within a precise range, and the switching speed of the IGBT module can be controlled.

For the convenience of description, referring to Fig. 5, the working process of the third embodiment of the present invention is described in conjunction with the second application circuit of the IGBT switch control circuit. The control method of the IGBT switch control circuit provided by the present invention is not limited to the IGBT switch control Two application circuits of the circuit:

The second application circuit of the IGBT switch control circuit includes the drive resistance switch array 4, the voltage detection switch control 1, the IGBT module 3 and the parasitic inductance 2 of the IGBT module; Le1 and Le2 are the parasitic inductance of the IGBT module, and no special current detection is required device or inductance, the Le2 is the parasitic inductance on the emitter of the IGBT module, in the voltage detection switch module, the voltage detection switch module detects the voltage Us on le2, and the Us is di/dt in the parasitic The voltage generated on the inductance is generally composed of analog devices for voltage detection, and can also be detected by a dedicated voltage detection device. The present invention does not specifically limit this. The switch detection module obtains the detection voltage on the voltage detection module. The detection voltage is compared with a preset threshold, wherein the preset threshold is a value stored in the switch control module, and an IGBT gate current control signal is output according to the comparison result, and when the detection voltage is greater than the first When a threshold value is reached, the IGBT gate current reduction signal is output, and the resistance connected to the drive resistance switch array 4 increases, for example, the originally connected parallel resistors Rg and R2 are increased and then connected in parallel with a resistor R3 and Rn, correspondingly The current input to the gate of the IGBT module will decrease, and when the detection voltage is less than the second threshold, the IGBT gate current increase signal will be output, and the resistance of the drive resistance switch array connected to 4 will decrease. small, the corresponding input current to the gate of the IGBT module will increase. In this embodiment, the resistance of the IGBT module connected to the module can be changed by changing the connection mode of the resistance in the drive resistance switch array 4. The present invention does not specifically limit it.

Implementing this embodiment has the following beneficial effects:

When the detection voltage is greater than the first threshold, output an IGBT gate current decrease signal, and when the detection voltage is less than the second threshold, output an IGBT gate current increase signal to reduce the detection voltage Stable between the first threshold and the second threshold, control the magnitude of the IGBT gate current by comparing the detection voltage, monitor the switching dynamic process of the IGBT in real time, and adjust the gate current in real time to control the IGBT The switching speed can avoid the IGBT turn-off overvoltage peak and the overheating failure caused by too long switching time.

Embodiment four

On the basis of embodiment two or embodiment three,

Preferably, the outputting the IGBT gate current reduction signal is specifically outputting a resistance increase signal to the resistance adjustment unit, so that the gate drive resistance on the IGBT module is increased to reduce the gate current of the IGBT module; The outputting the IGBT gate current increase signal is specifically outputting a resistance decrease signal to the resistance adjustment unit, so that the gate drive resistance on the IGBT module decreases to increase the gate current of the IGBT module.

In this embodiment, the resistance adjustment unit is connected to the gate of the IGBT module, and when the resistance increase or decrease signal is output to the resistance adjustment unit, the resistance value of the resistance adjustment unit can be changed to change the resistance of the resistance adjustment unit. into the gate drive resistor of the IGBT module.

In this embodiment, the resistance adjustment unit can adjust the resistance by adjusting the main circuit structure or directly adjusting the size of the IGBT gate drive resistance, which is not specifically limited in the present invention.

Implementing this embodiment has the following beneficial effects:

Output a resistance increase signal to the resistance adjustment unit, so that the gate drive resistance on the IGBT module increases to reduce the gate current of the IGBT module; the output IGBT gate current increase signal is specifically to adjust the resistance The unit outputs a resistance reduction signal, so that the gate drive resistance on the IGBT module decreases to increase the gate current of the IGBT module. By changing the gate resistance connected to the IGBT module, the The gate current of the IGBT module controls the switching speed of the IGBT, monitors the switching dynamic process of the IGBT in real time, adjusts the gate current in real time to control the switching speed of the IGBT, and avoids the IGBT turn-off overvoltage peak and the long switching time. Overheating fails.

Embodiment five

On the basis of embodiment two or embodiment three,

The output IGBT gate current reduction signal is specifically to output a current extraction signal to a bidirectional power supply, so that the bidirectional power supply draws current from the gate of the IGBT module; the output IGBT gate current increase signal is specifically to a bidirectional power supply. The power supply outputs a current injection signal, so that the bidirectional power supply injects current into the gate of the IGBT module.

In this embodiment, the bidirectional power supply has bipolar voltage/current output, which can output positive or negative polarity voltage, and can also absorb or supply current. Simply put, it can supply power or consume power, and is mainly used for To simulate battery characteristics, it is possible to extract current from the gate of the IGBT module and inject current into the gate of the IGBT module.

Implementing this embodiment has the following beneficial effects:

The output IGBT gate current reduction signal is specifically to output a current extraction signal to a bidirectional power supply, so that the bidirectional power supply draws current from the gate of the IGBT module; the output IGBT gate current increase signal is specifically to a bidirectional power supply. The power supply outputs a current injection signal, so that the bidirectional power supply injects current into the gate of the IGBT module, thereby controlling the switching speed of the IGBT, monitoring the switching dynamic process of the IGBT in real time, adjusting the gate current in real time to control the switching speed of the IGBT, Avoid IGBT turn-off overvoltage spikes and overheating failures caused by excessive switching time.

Embodiment six

Referring to Fig. 6, the present invention provides a control device for an IGBT switch control circuit, which is used to control the switching process of the IGBT module, including:

A detection voltage acquisition module 20, configured to obtain in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter;

A comparison module 21, configured to compare the detected voltage with a preset threshold;

The signal output module 22 is configured to output an IGBT gate current control signal according to the comparison result, so as to stabilize the detection voltage at the preset threshold.

In a first possible implementation manner, the signal output module 22 includes:

output an IGBT gate current increase signal when the detection voltage is less than the preset threshold, and output an IGBT gate current decrease signal when the detection voltage is greater than the preset threshold, so as to stabilize the detection voltage at The preset threshold.

In a second possible implementation manner, the preset threshold includes: a first threshold and a second threshold, where the first threshold is greater than the second threshold;

Then the signal output module 22 includes:

When the detection voltage is greater than the first threshold, output an IGBT gate current decrease signal, and when the detection voltage is less than the second threshold, output an IGBT gate current increase signal to reduce the detection voltage stable between the first threshold and the second threshold.

In combination with the first possible implementation and the second possible implementation, in the third possible implementation, the outputting the IGBT gate current reduction signal is specifically outputting a resistance increase signal to the resistance adjustment unit, so that the IGBT The gate drive resistance on the module is increased to reduce the gate current of the IGBT module; the output IGBT gate current increase signal is specifically to output a resistance reduction signal to the resistance adjustment unit, so that the IGBT module on the The gate drive resistance is reduced to increase the gate current of the IGBT module.

In combination with the first possible implementation and the second possible implementation, in a fourth possible implementation, the outputting the IGBT gate current reduction signal is specifically outputting a current extraction signal to the bidirectional power supply, so that the bidirectional power supply The gate of the IGBT module draws current; the outputting the IGBT gate current increase signal is specifically outputting a current injection signal to a bidirectional power supply, so that the bidirectional power supply injects current from the gate of the IGBT module.

Implement the present invention, have following beneficial effect:

In the process of controlling the switching of the IGBT module, by obtaining in real time the detection voltage on the parasitic inductance between the emitter of the IGBT module and the lead terminal corresponding to the emitter, and comparing the detection voltage with a preset threshold; Output the IGBT gate current control signal according to the comparison result to stabilize the detection voltage at the preset threshold, and monitor the change state of the di/dt value of the IGBT module in real time by monitoring the detection voltage, that is, realize Monitoring the dynamic process of di/dt during the switching period of the IGBT module, and then controlling the gate current input to the IGBT module through the detection voltage, thereby optimizing the turn-off speed of the IGBT module and avoiding overvoltage Ineffective, optimize the turn-off loss and conduction loss, and solve the problem that in the prior art, Vce cannot control the change of di/dt below the clamping voltage point and cannot control di/dt during the turn-on period, so that the IGBT turn-on process cannot be controlled to the maximum problem of optimization.

The above description is a preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and deformations can also be made, and these improvements and deformations are also considered Be the protection scope of the present invention.

Claims (10)

1. a kind of control method of IGBT ON-OFF control circuit, which is characterized in that for controlling the switching process of IGBT module, wrap It includes：

It is obtained on the emitter to the parasitic inductance between the corresponding lead terminal of the emitter of the IGBT module in real time Detect voltage；

The detection voltage is compared with preset threshold；

IGBT grid current is exported according to comparison result and controls signal, by the detection voltage stabilization in the preset threshold.

2. the control method of IGBT ON-OFF control circuit as described in claim 1, which is characterized in that described according to comparison result It exports IGBT grid current and controls signal, include in preset threshold by the detection voltage stabilization：

When the detection voltage is less than the preset threshold, output IGBT grid current increases signal, big in the detection voltage IGBT grid current is exported when the preset threshold and reduces signal, by the detection voltage stabilization in the preset threshold.

3. the control method of IGBT ON-OFF control circuit as described in claim 1, which is characterized in that the preset threshold packet It includes：First threshold and second threshold, wherein the first threshold is greater than the second threshold；

It is then described that IGBT grid current control signal is exported according to comparison result, by the detection voltage stabilization described default Threshold value includes：

When the detection voltage is greater than the first threshold, output IGBT grid current reduces signal, in the detection voltage When less than the second threshold, output IGBT grid current increases signal, by the detection voltage stabilization in first threshold Between value and the second threshold.

4. the control method of IGBT ON-OFF control circuit as claimed in claim 2 or claim 3, which is characterized in that the output IGBT It is specially to increase signal to resistance adjustment unit output resistance that grid current, which reduces signal, so that the grid in the IGBT module Driving resistance increases to reduce the grid current of the IGBT module；The output IGBT grid current increase signal be specially to Resistance adjustment unit output resistance reduces signal, so that the gate driving resistance reduction in the IGBT module is described to increase The grid current of IGBT module.

5. the control method of IGBT ON-OFF control circuit as claimed in claim 2 or claim 3, which is characterized in that the output IGBT It is specially to export current draw signal to bi-directional power that grid current, which reduces signal, so that the bi-directional power is from the IGBT mould The grid of block extracts electric current；It is specially to bi-directional power output electric current injection letter that the output IGBT grid current, which increases signal, Number, so that grid Injection Current of the bi-directional power to the IGBT module.

6. a kind of control device of IGBT ON-OFF control circuit, which is characterized in that for controlling the switching process of IGBT module, wrap It includes：

It detects voltage and obtains module, for obtaining the emitter of the IGBT module in real time to the corresponding lead end of the emitter Detection voltage in parasitic inductance between son；

Comparison module, for the detection voltage to compare with preset threshold；

Signal output module controls signal for exporting IGBT grid current according to comparison result, and the detection voltage is steady It is scheduled on the preset threshold.

7. the control device of IGBT ON-OFF control circuit as claimed in claim 6, which is characterized in that the signal output module Including：

When the detection voltage is less than the preset threshold, output IGBT grid current increases signal, big in the detection voltage IGBT grid current is exported when the preset threshold and reduces signal, by the detection voltage stabilization in the preset threshold.

8. the control device of IGBT ON-OFF control circuit as claimed in claim 6, which is characterized in that the preset threshold packet It includes：First threshold and second threshold, wherein the first threshold is greater than the second threshold；

Then the signal output module includes：

When the detection voltage is greater than the first threshold, output IGBT grid current reduces signal, in the detection voltage When less than the second threshold, output IGBT grid current increases signal, by the detection voltage stabilization in first threshold Between value and the second threshold.

9. the control device of IGBT ON-OFF control circuit as claimed in claims 6 or 7, which is characterized in that the output IGBT It is specially to increase signal to resistance adjustment unit output resistance that grid current, which reduces signal, so that the grid in the IGBT module Driving resistance increases to reduce the grid current of the IGBT module；The output IGBT grid current increase signal be specially to Resistance adjustment unit output resistance reduces signal, so that the gate driving resistance reduction in the IGBT module is described to increase The grid current of IGBT module.

10. the control device of IGBT ON-OFF control circuit as claimed in claims 6 or 7, which is characterized in that the output IGBT It is specially to export current draw signal to bi-directional power that grid current, which reduces signal, so that the bi-directional power is from the IGBT mould The grid of block extracts electric current；It is specially to bi-directional power output electric current injection letter that the output IGBT grid current, which increases signal, Number, so that grid Injection Current of the bi-directional power from the IGBT module.