Electronics > Projects, Designs, and Technical Stuff
Bipolar vs Mosfet for full bridge driver
wizard69:
As far as I can tell there is only disadvantages. I started out in industry many decades ago and one of my jobs was to fix PTI drives that only had to drive a 1/2HP motor. These dives where huge and extremely troublesome compared to anything modern. One transistor module on those old drives is today replaced by an entire drive that fits into the palm of your hand.
As fr what those fancy new drives have in them I would suggest that you need to actually look up what the manufacture acutely used for power output. Some may be MOSFET but you will still find IGBT modules on some drives. The reality is that as a switch MOSFETS can have a very low on resistance leading to very small devices and tiny passive coolers if they have a fan at all.
From the engineering stand point there are always trade offs but the fact that MOSFETS have taken over so many of "power" niches kinda indicates that they are often the best tech for low voltage systems.
As for Bipolar I can't think of any advantages these days.
--- Quote from: ricko_uk on June 12, 2020, 08:32:09 pm ---Hi,
most bridge motor drivers nowadays are mosfet. Is there any advantage whatsoever in using bipolar ones instead? It looks like they perform worst in terms of power dissipation voltage drop etc. Do they have any advantage?
Thank you :)
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filssavi:
--- Quote ---As for Bipolar I can't think of any advantages these days.
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For low voltages you are correct, however for higher voltages (from 4/500V dc link) right now apart from the odd SiC mosfet everything is IGBT which has bipolar in the name 8)
The advantages are drastically lower losses per unit area at the same blocking voltage, with respect to unipolar e devices, now wide band gap are changing that, but it is only because nobody has figured out yet how to do a SiC IGBT (or a decent one anyhow)...
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