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Old 08-01-2017, 04:03 AM   #3149 (permalink)
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Originally Posted by MPaulHolmes View Post
Hello! I don't think there's a difference between PMAC and brushless DC. Well, I think sometimes PMAC wants a pure AC waveform for best results, and brushless DC wants trapezoidal? But I'm not sure. Also, both motors work fine with an AC waveform.

If it's a permanent maget motor, and you have an encoder, you shouldn't need different firmware. You might just have to set the number of pole pairs, motor type (permanent magnet with encoder) etc.

That would be absolutely awesome to go through the whole tuning process and everything. That's something that I should have done and never got around to doing.
Hey! Long time no join this conversation. Finishing my computer engineering degree, looking for a job has had me busy.

You're correct on the differences between PMAC and Brushless IF the PMAC is single-phase. Just a difference of optimizations for field-to-field contact, should be pretty small in differences too.

There are PMAC motors that are three-phase and will run MUCH less efficiently wired in single-phase or PWM. Due to mismatched PM-field to AC-field alignment in timing. If it's a motor they bothered to do such optimizations for, anyway. Unoptimized designs I wouldn't be surprised if they don't account properly and act like single-phase anyway.

Exact optimal waveform for PMAC is typically sinusoidal. BLDC... vary. I've seen a few list triangular, some trapzoidal, some CLAIM square(but we well know true square waves are a pipedream). Trapizodal seems the best assumption though since it makes the most physics sense. (I've seen triangular on fine motion motors, nowhere else.)

Been great watching this controller become a thing.
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