igbtmsp430opto-isolator
I am trying to test IGBT switching using the following circuit but the IGBT smoked out. I am using MSP430 with g2553 chip, NMK0505SAC dc-dc converter, FOD3184 optocoupler and IRG4BC20UD. Please help me if you find anything wrong with my circuit connection.
I suggest you read TI app note SLUP100, "Snubber Design" by Philip C. Todd for some good background on snubber design.
When the triac is on, the dissipation through the snubbers will be low since they are 'shorted' by the triac.
When the triac is off, load current is going to try and flow through both of your snubber circuits, and the resistors are going to see power dissipation.
Are you absolutely sure that the triac is firing each cycle?
There are many possible schematics. IGBTs are best driven with high voltage high-pulsed-current-drive 15V/-5V drive and of course you want isolation or you wouldn't be asking for an opto. You may be able to get away with +15/0V drive in some circumstances.
Here is one chip that will do the opto part and the driver part, and is similar to the one you are wanting to use. You still have to deal with giving it +15/-5 or at least +15V/0 relative to the emitter on the high side driver.
Probably for such a low power level a bootstrap diode would be an appropriate approach (limited to +V drive only). So, something like a UF4007 connected to a low voltage supply on the mains side. Ask if you don't know what a bootstrap is, or see most any of the IR application notes on half-bridge drivers.
The LED drive circuit most recommended is the shunt circuit (have your micro drive a transistor to shunt the LED, with a series resistor or resistors to the supplies).
Best Answer
The FOD3184 needs a power supply of at least 13.5V (15V~30V recommended) and the IRG4BC20UD needs 15V Gate drive to turn on fully, but the NMK0505SAC dc-dc converter only puts out 5V. You should be using a 5 to 15 Volt DC-DC converter (eg. NMK0515SAC).