Originally Posted by
joeavaerage
Hi,
You may be going down a rabbit hole. Yes components like the bridge rectifier, DCLink capacitors, InRush resistors and relays can and do blow up, but there is usually a single cause,
and its usually fatal. If one or more of the IGBTs or MOSFETS have failed then it highly probable it will short the DCLink and that in turn will blow the rectiers/resistors etc.
You need to test the integrity of the IGBTs/MOSFETs. You need a variable voltage DC power supply moderate current ability, say 3A. Hook this to the DCLink with a big 300w
resistor, say 50Ohm, and slowly increase the voltage, up to at least 100VDC. If the IGBT's/MOSFETs cant resist 100VDC, then what hope do they have at 320VDC, the operating
DCLink voltage? The big series resistor is for current limiting in the event the IGBTs/MOSFETs are faulty, it should save your power supply and stop it blowing up in your face.
If the IGBTs/MOSFETs are faulty, that is cannot withstand 300-400VDC, then give up. Replacing them is possible but the reliability in service is likely to be poor. I have done so
for high powered and very expensive welders, but really its a gamble at best. The last one I did was a $20,000 Fronius, and the owner was adamant that it be fixed, despite the power board
no longer being available as a spare part and was $8000 when it was!
Craig