Electronics > Projects, Designs, and Technical Stuff
Ideal buck converter for high current
Jay_Diddy_B:
Hi,
So you 360F in a 3S2P configuration.
This is 240F
After the weld the voltage drops to 6V and you need to charge back to 8.1V
CV=It
240F x 2.1V = 504 As
If you use 20A charge current the charge time will be about 25 seconds to charge from 6V to 8.1V
Designing a poly-phase high current buck is NOT a good project for somebody who hasn't built one before.
Jay_Diddy_B
Pawelr98:
Have you considered another approach ?
That is making the HP supply output those 8V instead of building a massive buck converter.
Add a series inductor to limit the current spike and it should be OK-ish.
Look into the feedback loop of the HP supply and check if there are any safety functions such as undervoltage protection.
anishkgt:
--- Quote from: Pawelr98 on August 03, 2020, 09:13:30 pm ---Have you considered another approach ?
That is making the HP supply output those 8V instead of building a massive buck converter.
Add a series inductor to limit the current spike and it should be OK-ish.
Look into the feedback loop of the HP supply and check if there are any safety functions such as undervoltage protection.
--- End quote ---
Not sure how practical it would be to have an inductor in series.
anishkgt:
--- Quote from: Jay_Diddy_B on August 03, 2020, 08:16:07 pm ---Hi,
So you 360F in a 3S2P configuration.
This is 240F
After the weld the voltage drops to 6V and you need to charge back to 8.1V
CV=It
240F x 2.1V = 504 As
If you use 20A charge current the charge time will be about 25 seconds to charge from 6V to 8.1V
Designing a poly-phase high current buck is NOT a good project for somebody who hasn't built one before.
Jay_Diddy_B
--- End quote ---
Thank you mate appreciate your concern.
I know the traces has to be routed bearing mind to keep the digital, analog and the inductors traces separated. There is always a first time for everything. To begin with i am looking at the ADP1850. Seems to be built for the kill.
David Hess:
--- Quote from: wraper on August 03, 2020, 04:46:07 pm ---
--- Quote from: CoteRotie on August 03, 2020, 04:35:35 pm ---8.1V and 82A is unequivocally in multi-phase synchronous rectified territory.
--- End quote ---
Yeah, to achieve this in one phase would require some ridiculous inductor and diode + MOSFET bank. And efficiency will suck = a lot of heat to somehow transfer away.
EDIT: and PWM controller probably won't be able to deal with a gate charge of such MOSFET bank anyway.
--- End quote ---
It could be done at the expense of power density and closed loop bandwidth. The higher operating frequency of smaller parallel multiphase converters allows for higher bandwidth for faster response and higher power density.
But winding and using high current inductors like that is more like plumbing.
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