Since the IGBT module is a MOSFET structure, the gate of the IGBT is electrically isolated from the emitter through a layer of oxide film. Since this oxide film is very thin, its breakdown voltage generally reaches 20 to 30V. Therefore, gate breakdown due to static electricity is one of the common causes of IGBT failure. Therefore, pay attention to the following points in use:
1. When using the module, try not to touch the drive terminal part by hand. When you must touch the module terminal, first discharge the static electricity on the human body or clothing with a large resistance to ground, and then touch;
2. When connecting the drive terminals of the module with conductive materials, do not connect the module before the wiring is not connected;
3. Try to operate with the bottom plate well grounded.
　　In application, although it is guaranteed that the gate drive voltage does not exceed the maximum rated voltage of the gate, the parasitic inductance of the gate connection and the capacitive coupling between the gate and the collector may also generate an oscillating voltage that damages the oxide layer. For this reason, twisted pairs are usually used to transmit drive signals to reduce parasitic inductance. A small resistance in series in the gate wiring can also suppress the oscillating voltage.
　　In addition, when the gate-emitter is open, if a voltage is applied between the collector and the emitter, as the collector potential changes, the gate potential increases due to leakage current flowing through the collector Then current flows. At this time, if a high voltage exists between the collector and the emitter, the IGBT may heat up and be damaged.
　　In the case of using IGBT, when the gate circuit is abnormal or the gate circuit is damaged (the gate is in an open state), if a voltage is applied to the main circuit, the IGBT will be damaged. A resistor of about 10KΩ is connected in series between the electrode and the emitter.
　　When installing or replacing an IGBT module, great attention should be paid to the state of the contact surface and tightening degree of the IGBT module and the heat sink. In order to reduce the contact thermal resistance, it is best to apply thermal grease between the heat sink and the IGBT module. Generally, a cooling fan is installed at the bottom of the heat sink. When the heat sink is damaged, the heat dissipation of the heat sink will cause the IGBT module to heat up and malfunction. Therefore, the cooling fan should be checked regularly. Generally, a temperature sensor is installed on the heat sink near the IGBT module. When the temperature is too high, it will alarm or stop the IGBT module.