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CCS/TMS320F28069M: Torque from rotor flux

JNV
Prodigy 80 points

Part Number: TMS320F28069M

Tool/software: Code Composer Studio

Hi,

I’m trying to calculate the instantaneous torque of a PMSM from the q-axis current and the rotor flux.

In the video “Teaching old motor new tricks”, which by the way is very helpful, it’s said that the torque=3/2*P/2*(lambda_dr*Iqs)

P:poles

Lambda_dr:rotor flux

In this post: e2e.ti.com/.../277190

David said “the motor torque can be calculated by simply multiplying the rotor flux linkage times the q-axis stator current times the number of rotor poles/2”.

I’m a little confused here.

 

The final goal is to compare experience (TI board) from simulation (Matlab).

From the Instaspin motion labs, the rotor flux is estimated to 0.103V/Hz:

But when I try to adjust settings of the PMSM Matlab model from my motor datasheet, it estimates the rotor linkage flux to 0.0174444 V.s:

Do you have detail of how Instaspin motion estimate the rotor flux linkage?

Thanks a lot!

  • 0
    TI__Guru** 117230 points
    In instaSPIN, the Flux is flux linkage between the rotor and the stator based on motor. Generally, motor manufacturer can provide this parameters and we need to use this parameters to setup motor model for simulation.
    Maybe, you need to set a correct Voltage Constant for the Flux calculation in Matlab.
  • 0 in reply to Yanming Luo
    Prodigy 80 points
    Thank you Yanming for your answer. On the Matlab screenshot, the right part is calculated by Matlab according to the given datasheet parameters on the left part. The Voltage constant (56.95V/krpm) is estimated by matlab and is also very close to the one given by the motor datasheet (57V/krpm).