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TMS320F28069M: Starting FOC on a spinning motor

Martin Bayer
Prodigy 140 points
Part Number: TMS320F28069M

Hello,

I am using TI InstaSpin FOC software on a TMS320F28069M, integrated in a high voltage board with PMSM motor.

In our application, the motor is coupled with a high speed fan.

The fan could be driven by the medium, also if the motor is unpowered.

I am looking for a hint, how to start the instaspin FOC routines, if there is already a certain speed on the motor.

It is clear, that it does not make sense, to use recalibration routines (e.g. for motorresistance or offset-values),

because of the routines would apply measure-currents to the spinning motor.

Is it only an issue to provide the detected motorspeed as target speed to the rpm-controller?

Regards

Martin Bayer

  • 0
    TI__Guru** 114200 points
    Hi Martin,

    Please refer to proj_lab10e in MW17 which supports flying start can enable the motor startup/re-startup from spinning, and should meet your requirements.
  • 0 in reply to Yanming Luo
    TI__Expert 3515 points

    Hi  Yanming,

    For flying start, when the motor is spin in the same rotation direction with our driver, it's good.

    BUT, when the motor is initially spin in the opposite direction, the main voltage would increase from 320 to 380 in short time.

    Could you help advise? Thanks!

  • 0 in reply to LLouis
    TI__Intellectual 1620 points

    Hi Yanming,

    any update on this?

    Could you please support or forward the thread to a colleague who could help?

    Thanks and best regards,

    B

  • 0 in reply to Basil
    TI__Guru** 114200 points
    It seems the inertia of motor/load is very big in this case, the reference torque current can't follow the motor speed which cause the motor work in generator mode to boost the voltage. So you need to set a small acceleration and adjust the speed&Current PI regulator to decrease the motor to ZERO first, and then run in opposite. You have to add an external code to limit the reference torque current to set the sign is the same as motor direction, and to switch the run direction.

    Actually, lab10e had the flying start function to meet your requirement, you can refer to the lab and bypass the offset calculation process.

    Btw, what's the opposite speed to switch the run direction? Did the motor work in field weakening mode? If no, you can use brake mode to stop the motor first if the motor speed is not too high, and then run in right direction.