How to Measure Rs, Ls, BEMF Constant, and Max RPM of a PMSM Motor for STM32 FOC Tuning

[Vedant07]

Hi all,

I'm working with an STM32-based motor control setup ( The EVSPIN32F0251S1 board is a 3-phase complete inverter based on the STSPIN32F0251 controller), and I have a physical PMSM motor that I want to use with FOC (Field Oriented Control).

I need help figuring out the following motor parameters:

Parameters I want to find:

Stator resistance (Rs in Ohms)

Stator inductance (Ls in mH)

Back-EMF constant (in Vrms/kRPM or Vpeak/kRPM)

Maximum mechanical RPM

What I have:

Physical motor only and basic data (no datasheet)

PMSM motor

Volt -24

Current -4.3 amp

Power -105W

RPM - 500 Hz- 83.3 Hz

Pole Pair -10

Torque -2.0 Nm

Can measure with multimeter, oscilloscope, etc.

Using STM32 Nucleo-F446RE board Planning to use STM32 Motor Control Workbench & SDK

My questions: What is the best method to measure Rs and Ls accurately with basic lab equipment?

How can I measure or estimate the BEMF constant?

Is there a reliable way to determine the maximum safe RPM if the motor model is unknown?

Can the STM32 MC Workbench help extract these automatically?

Any guidance, measurement techniques, or scripts/tools would be much appreciated!

Thanks in advance!

[GMA · Accepted solution]

Hello @Vedant07;

You can use MC Motor profiler tool provided on MCSDK available here. Feature is available using Nucleo-F446RE board.

You can also have a look to How To manually configure the motor parameters link.