Switching frequency of synchronous motor

Thread Starter

electronicsLearner77

Joined May 26, 2012
125
I am doing 6 step commutation of 3 phase Synchronous motor. The pwm frequency is around 10khz. I read the formula from the documents for synchronous speed as 120 * f / p. What is the "f" here is it 10khz ? Please advise.
 

crutschow

Joined Mar 14, 2008
23,378
"f" is the PWM modulation frequency, not the PWM switching frequency.
f would be 50-60Hz for standard motor operation.
Are you trying to control the synchronous motor speed with the PWM signal?
 

Thread Starter

electronicsLearner77

Joined May 26, 2012
125
Not sure but in documents i read that the switching frequency should be high to avoid audible noise. How to program the pwm modulation frequency ? I mean to say i want higher speeds how to increase modulation frequency ?
 

MaxHeadRoom

Joined Jul 18, 2013
19,067
Picmicro recommend PWM motor control starting at around 5khz to 6khz to avoid audible buzz or noise, for a very small motor that might be an insignificant factor.
Max.
 

danadak

Joined Mar 10, 2018
3,578
What do you mean by "120" mode ? Just the fact you are
switching in each phase of a 3 phase system ?

The ref I gave you not exact solution to your problem, more
generalized considerations for 3 phase motor control.

Regards, Dana.
 
Top