PMSM_FOC sensorless control issue

[User22355]

Hi,
I am using the PMSM_FOC v1.5.8 for XMC1300 to run a PMSM motor. I am using the XMC1300 boot kit with a custom inverter with internal ADC gains for the three phase current sense.
I have measured the parameter by providing a voltage step on the U-V terminals of the motor while leaving the W phase unconnected. This gave me L_equ and R_equ.
I considered
L_motor = L_equ /2
R_motor = R_equ/2
and used these values as the motor parameters for the controller.
The motors spins in the SPEED_CONTROLLED_VF_MET_FOC and goes into FOC closed loop state. In this state the rpm of the motor follows the speed command. However, in the VQ_CONTROLLED_DIRECT_FOC, the motor oscillates about its initial position and I am unable to run the motor. I have referred to the getting started guide for the instructions on tuning the controller.
After a few hours of changing the parameters of the Flux PI loop, I obtained phase currents that look somewhat sinusiodal (under a small load). The image of the currents are attached.

Am I right in understanding that this issue is due to improper tuning of the flux loop?
What can I do to fix the issue?

Thank you

[Krupashankar · Accepted solution]

Hi @User22355 ,

 VQ_CONTROLLED_DIRECT_FOC starts from closed loop by attaining position of the rotor, but SPEED_CONTROLLED_VF_MET_FOC starts at open loop and transitions to closed loop. Here MCE cannot detect the initial position of rotor in VQ_CONTROLLED_DIRECT_FOC and from your waveform we could find that current wave is imbalanced. Could you please share the current waveform with no load connected to motor and please share the details of current sensing circuit as we could see current imbalance.

Thanks,

Krupashankar