seyyah
Advanced Member level 2
I designed a 3 phase inverter with 6 discrete 600V rated IGBTs. I applied 10 KHz SPWM to the AC motor(2.2KW induction machine) via the inverter. DC bus is obtained from 380VAC rectification which is @537VDC at no load. I burnt some of the igbts at first try. Then i reduced DC BUS voltage to 300VDC. Tried again at first it didn't burn, but then again. Why is it burning? Due to high voltage at turn off? Do i need a snubber?
I tried the inverter at low voltage (35V) and with a low power ac motor. It worked without problem. But at high voltage, high side is not switching appropriately when dc bus is online. Without dcbus is online, high side is ok. My gate driver is IR2113 based and i tried bootstrap capacitors from 10uF to 470uF. I saw some designs working well similar to mine with low value bootstrap capacitors. What may be the problem?
Please help me because i'm stuck now and don't know what to do and don't want to burn another igbt. Thanks.
I tried the inverter at low voltage (35V) and with a low power ac motor. It worked without problem. But at high voltage, high side is not switching appropriately when dc bus is online. Without dcbus is online, high side is ok. My gate driver is IR2113 based and i tried bootstrap capacitors from 10uF to 470uF. I saw some designs working well similar to mine with low value bootstrap capacitors. What may be the problem?
Please help me because i'm stuck now and don't know what to do and don't want to burn another igbt. Thanks.