Repair Case
IGBT Keeps Blowing After Replacement
Use this page when a replacement IGBT/MOSFET fails immediately or after a short welding test.
Root-cause checklist
| Area | Check | Reason |
|---|---|---|
| Gate drive | Gate resistor, fast diode, driver transistor, waveform symmetry | Bad drive destroys new devices quickly |
| Snubber / absorption | Capacitor, resistor, TVS/RCD path | Overvoltage spikes exceed device rating |
| Output rectifier | Diode-mode and short test | Secondary short reflects stress to inverter stage |
| DC bus | Capacitors, bridge, precharge path | Abnormal bus causes excessive stress |
Power-up rule
Do not install expensive power devices and apply full mains immediately. First confirm auxiliary rails, gate waveform and absence of output-side shorts, then power through a current limiter.