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TMS320F28030: Regeneration in sinusoidal Third harmonic injection commutation

Amit Patil1
Prodigy 140 points

Part Number: TMS320F28030

Hi All,

I have developed sinusoidal third harmonic injection commutation for a PMSM motor. I am using hall sensors to estimate angle in between two hall states and generating sine saddle PWM using Sine-THI Lut table. Everything is working smoothly.

But i am facing the issue when i reduce the torque command, it starts regenerating heavily. I am just reducing the duty of PWM, not doing anything for regeneration.

Why it regenerates automatically? and how to avoid it. Please provide some light on it.

Thanks

  • 0
    TI__Guru** 116880 points

    Sorry, it's difficult to provide much more supports or you since you are working on your own algorithm. Please make sure that the rotor position is detected correctly to start/run the motor, and set the right torque current and acceleration to start the motor.

  • 0 in reply to Yanming Luo
    Prodigy 140 points

    i have one issue of regen in sinusoidal commutation. when i reduce the speed, it starts regenerating. due this phenomenon my speed also reduced. i want it to coast. please give some idea how to avoid speed reducing due to regen? or how to avoid regen?

  • 0 in reply to Amit Patil1
    TI__Guru** 116880 points

    Sorry, I'm not fully understand your question. Could you please provide more information since you are working on your own algorithm, not TI reference code.

    Are you working on sensorless-FOC or sensored-FOC based PMSM drive? 

  • 0 in reply to Yanming Luo
    Prodigy 140 points

    I am working on Sensored-Sinusoidal Commutation. I have developed LUT table of sine and based on motor angle i pick the value from the table and multiply with the torque command which directly goes to PWM module. If you plot the table data then you will the Sine wave. 

    Everything is working fine there except unwanted Regeneration. When i reduce the torque command, it starts regenerating and my motor speed also gets reduced. So i want to know why regen is happening there. i have worked on Sesnored-FOC but no regen takes place there if you reduce the torque command. Motor runs with the momentum.

  • 0 in reply to Amit Patil1
    TI__Guru** 116880 points

    The issue should be from your own motor control algorithm, the rotor angle is not correct to set the right torque current for control the machine in motor mode that enables the machine run in the second/fourth quadrant with generator mode. Sorry, we can't provide more detailed suggestion for you without enough information since you are not any TI reference code.