DRV8323: Downside to using 3x PWM mode for FOC motor control

Brett Nourrcier

Part Number: DRV8323

Hey Guys - is there a downside to using 3x PWM mode when setting up FOC motor control? My thinking is the dead band control in the DRV8323 eliminates the need for 6x PWM. I ask because the reference designs (at least the ones i've looked at) always use 6x PWM mode. Is seems like 3x would be better (less traces between MCU and DRV if nothing else) if get same performance.

Thanks!

Brett

over 4 years ago

0 Adam Sidelsky over 4 years ago

TI__Guru 62730 points

Brett,

Thanks for posting on the MD forum!

Let me check this with the 6x system designers and I’ll get back to you tomorrow.

Regards,

-Adam

0 Adam Sidelsky over 4 years ago in reply to Adam Sidelsky

TI__Guru 62730 points

Brett,

3x can easily be used for FOC as FOC doesn't usually use Hi-Z states in it's operation. The reason we often see 6x used is because many MCUs are setup for 6x PWM already. We have seen customers implement 3x PWM successfully.

Some systems do use a very brief Hi-Z state for current or BEMF measurement which would then require 6x PWM.

Regards,

-Adam

0 Brett Nourrcier over 4 years ago in reply to Adam Sidelsky

Intellectual 905 points

OK. Thanks Adam.

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DRV8323: Downside to using 3x PWM mode for FOC motor control