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minimum and maximum RPM using FOC

Oussama Belhedi
Associate

hello,

is there any recommanded speed limits (in rpm) to get an optimal and realiable speed control using FOC?

thank u 😁

1 ACCEPTED SOLUTION

Accepted Solutions
Dario CUCCHI
Senior II

Hello @Oussama Belhedi​ ,

I can’t tell specific limits on the speed as they depends on many different factors such as:

  • the kind of motor
  • the microcontroller implementing the algorithm
  • the FOC algorithm configuration, if sensorless or with sensor, single shunt or three shunt, and so on...

To better explain, let me provide some examples:

In a sensorless FOC, the rotor position is detected estimating the BEMF (Back Electromotive Force) of the motor.

At low speeds the BEMF is smaller, so it is more difficult to estimate the BEMF.

In general using positioning sensor on the motor provides more precision, because the position feedback is measured and not estimated.

Then, how much is the lower speed depends on the motor itself: let me say… running at 300 rpm a motor with a nominal speed of 30000 rpm is very hard :anxious_face_with_sweat: .

Running at the same speed a motor with a nominal speed of 1000 rpm is much simple :D

About higher speeds... In general higher speeds requires more computations, so the higher limit is determined by the performance of the microcontroller.

Hope my answer helps you. In this case don’t forget to click on the “Select as Best�? button here below 😉

View solution in original post

1 REPLY 1
Dario CUCCHI
Senior II

Hello @Oussama Belhedi​ ,

I can’t tell specific limits on the speed as they depends on many different factors such as:

  • the kind of motor
  • the microcontroller implementing the algorithm
  • the FOC algorithm configuration, if sensorless or with sensor, single shunt or three shunt, and so on...

To better explain, let me provide some examples:

In a sensorless FOC, the rotor position is detected estimating the BEMF (Back Electromotive Force) of the motor.

At low speeds the BEMF is smaller, so it is more difficult to estimate the BEMF.

In general using positioning sensor on the motor provides more precision, because the position feedback is measured and not estimated.

Then, how much is the lower speed depends on the motor itself: let me say… running at 300 rpm a motor with a nominal speed of 30000 rpm is very hard :anxious_face_with_sweat: .

Running at the same speed a motor with a nominal speed of 1000 rpm is much simple :D

About higher speeds... In general higher speeds requires more computations, so the higher limit is determined by the performance of the microcontroller.

Hope my answer helps you. In this case don’t forget to click on the “Select as Best�? button here below 😉