IGBT is the CPU of power electronic device and plays a pivotal role in power electronic conversion and control. In the inverter, the IGBT module is more important. However, IGBT modules often explode.
For some reason, the loss of the module is very huge, and the heat cannot be dissipated, resulting in extremely high internal temperature, gas generation, and breaking through the shell, which is the so-called IGBT explosion. Below, the reasons for the IGBT explosion are briefly introduced.
The reasons for IGBT explosion mainly revolve around internal factors, human factors, common factors and other factors.
1. Internal factors:
The essence of the explosion is that the heating power exceeds the cooling power, and the internal cause should be overheating.
2. Human factors:
●The incoming wire is connected to the terminal of the outgoing wire
●The inverter is connected to the wrong power supply
●The load is not connected as required
3. Common factors:
●Overcurrent: one is the short circuit of the load, and the other is that the logic at the control circuit is disturbed, which causes the components of the upper and lower bridge arms to pass through.
●Insulation damage
●Overvoltage: It is usually caused by the peak voltage generated by the line stray inductance under the action of extremely high di/dt. The solution is to design a high-performance absorption circuit to reduce the line stray inductance.
●Overheating: The IGBT cannot be fully turned on, and the loss of the component increases when there is current, and the temperature increase leads to damage.
● Communication bit error rate: After a period of communication, a sudden error message causes the IGBT to mislead and cause the IGBT to explode; the unstable operation of the FPGA program of the communication board causes the IGBT to mislead and cause the IGBT to explode .
4. Other factors:
●The response time of the overcurrent detection circuit in the circuit cannot keep up.
●IGBT short-circuit protection is to detect the saturation voltage drop, and the time left for the actuator is generally 10us (8 times overcurrent). It is easy to burn the pre-charging resistor and the IGBT in the braking unit when it is powered on.
●Technical problems: the copper bar is strained, the screws are not tightened tightly, etc.
● Short-term high current: There are many reasons, such as the dead zone is not set properly, the main circuit is overvoltage, and the absorption circuit is not well done.
●The driving power supply is also a problem that should be paid special attention to, the isolation and isolation, and the filtering and filtering.
●The motor shock feedback voltage is too large to cause the IGBT to explode. But the probability of explosion when charging is not very high.
●When the motor starts, the input voltage drops instantly and the capacitor discharges. After the input voltage is restored, the inrush current when the capacitor is charged is too large to cause the IGBT to explode.
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