For example, I use the IGBT circuit switch, using the same gate resistance and drive circuit.
Then use it to make a normal working current only 1A off the external circuit off time
And let a current up to 100A of the external circuit completely off the turn-off time,
Will there be a big difference between the two times?
Or that depends entirely on the drive part of the control of the gate G, CE voltage at both ends of the voltage is not much relationship?
IGBT is equivalent to MOSFET and GTR connector, and its turn on and off is similar to MOSFET. MOSFET is a unipolar switch, and GTR is a bipolar switch, so the turn-off of the IGBT is slightly different.
When the gate voltage begins to fall, the voltage at both ends and the current flowing are constant. When the gate voltage drops below the dead-band voltage, the voltage across the IGBT begins to rise, and the current flowing begins to decrease. The time of this decline is related to the size of the current, the greater the current, the longer the time. But the IGBT has the largest current limit can be turned off, when the current exceeds a certain value, IGBT can no longer turn off, and the occurrence of the engine effect, this time IGBT out of control, the gate is no longer work, this is a unique phenomenon of IGBT.
If both IGBTs are able to operate under these two currents, there is a difference in turn-off time.
When the shutdown signal is issued, due to the circuit can not avoid the role of inductance, the current will not immediately drop to 0, need to wait until the accumulation of the cathode in the CE gradually disappeared, in order to completely shut down. The greater the current, the more carriers that flow through, and the more the stacking, the longer the natural shutoff time.
Although there are differences, but such as IGBT power electronic devices, the difference is between several tens to two hundred milliseconds. I do not know this time for you is long and short.
Switch with IGBT, the switch time with the load current size does not matter.
IGBT can not control the size of the current, IGBT is only a switching device, when connected to the circuit, used to control the circuit off time. IGBT and inductance together to achieve the control of the current.
Take the voltage source as an example, only consider the main circuit, voltage source, IGBT, inductance, load series, when the IGBT is turned off, the power and inductance disconnected from the inductor to the load power supply, the inductor current can not be changed, but will decline. When the IGBT is turned on, the power supply and inductance connected to the power supply to the inductor and load power supply, the inductor current can not be mutated, but will rise. The current in the inductor and the rise of how much, by the IGBT turn off and open the time to determine, that is the IGBT turn on and off the law determines the law of the current changes in the inductor, also said that the realization of the current control.
It depends on whether you drive the load is not emotional components, and if not, that only with the G, if so, it had to be calculated, because the emotional components are induced electromotive force, the greater the current, the stronger the induced electromotive force , If it is 100A load, induced electromotive force will reach several thousand volts, must be added to the absorption circuit, which is not related to the characteristics of IGBT
