I just got an e-mail back from Electro Automotive from CC-Power regarding the failed DC-DC converter. I prefer not to comment on it but simply wish to pass it on to others who might have wondered what the manufacturer said. Here goes:
"The converters have been manufactured for over 20 years and we have 10,000+ units operating in South Africa at 120 volts, all using the same build, without any problems.
"The existing current limit system operates on a pulse by pulse basis and shuts the converter off immediately current exceeds a safe level. The method Kutscha is using has been tried and thrown out as it is not fast enough to protect the devices in an over-current situation. It also effects the transient response of the converter, causing the voltage to dip when load is increased and overshoot when load is removed."
"The problems he is experiencing are almost certainly voltage related than high current and are due to his installation, rather than the operation of the converter."
"The converter should be connected directly to the battery terminals. if he is connecting to the controller terminals, the problems of over voltage during regeneration will be much greater."
(okay one comment: no wonder the parts in this unit are so ancient! 20 years?!)
Cheers,
Tim
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3 comments:
I don't want to throw gasoline anywhere (pun intended). However the guy I work with thought R16 and C7 most likely aren’t ‘tuned’ in to the right values for the volts and amps your working with. He also wanted to know the speed of the D8 and D9.
Since it’s working now the point is likely moot anyway.
Joe
Hi Joe, I didn't really get to see the part numbers on D8 and D9. I did play with R16 and C7 a bit and they seem to dampen out the inductive spikes pretty well. Other values make larger spikes. I still think the problem was the gate drive pulses going wacky and getting too large due to the bad overcurrent feedback. I guess time will tell. It's still working, so I'm happy. :)
Cheers,
Tim
If South Africa ever had over 10,000 electric cars, then GM would still be selling the EV-1
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