Re: [unclassified] Re: [avr-chat] BLDC control with ATmega128?

[David Brown]

----- Original Message -----
From: "Rick Mann" <address@hidden>
To: "David Brown" <address@hidden>
Cc: <address@hidden>
Sent: Friday, February 03, 2006 11:32 AM
Subject: [unclassified] Re: [avr-chat] BLDC control with ATmega128?


>
> On Feb 3, 2006, at 12:35 AM, David Brown wrote:
>
> > It should be perfectly possible (assuming you have hall-effect
> > sensors on
> > the motor).  I don't think there is any real advantage in using PWM
> > for both
> > the top side and bottom side transistors for a BLDC motor (as
> > distinct from
> > a PMSM, where you *do* need them).
>
> What is PMSM?
>
> TIA!
>

Permanent Magnet Synchronous Motor.  The connections and windings are
similar to that of a BLDC, but optomised for running with three sin waves at
120 degree phase differences rather than BLDC trapezoid patterns.  Some
motors are happy with either type of driving patterns.  BLDC patterns are
much easier to generate, while PMSM patterns give finer control (for
example, you can lock the motor at a precise angle) and minimal current
ripple, but you need a much more powerful controller, and accurate angle
feedback (not just a hall-effect controller).