BLDC dead time

trialspower2

100 W
Joined
Dec 31, 2016
Messages
108
Should a BLDC controller have dead time between segments?

I know you can run without, as each phase does an off segment between going from high to low/ low to high.

I tried running with a micro second where everything was switched off on a segment change but this gave spikes as I expect it interrupts current flow.

So I can either run without or just have dead time on the high side keep the low side connected.i.e have a micro second between moving from one high side phase to the next as the segment changes.

I realise this is different to synchronous dead time, I have this dead time on each complimentary pair.
 
Good question. Most of the ones I have put on a scope don't appear to have dead time between commutation changes. As long as you don't let the complimentary pairs shoot through, seems like it should be OK. Spikes during commutation should not be any bigger than what you get when it's PWM switching. Off is off.

Spikes may possibly be measurement artifact.
 
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