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TMS320F28027F: When to disable force angle

Jordan Zhou
Genius 10210 points
Part Number: TMS320F28027F


Hi,

Force angle is used during motor starting up. After motor runs in a good way, force angle should be disabled.

My questions is, when is the point to disable force angle? How to judge the point?

Thanks a lot.

Br, Jordan

  • 0
    TI__Genius 17175 points
    While running without forced angle, you should try and step back the speed until you start to see instability in the speed loop. There is no precise transition point, as it depends on sensing and the motor feedback. With good sensing, InstaSPIN estimator should be able to achieve <10 Hz electrical frequency. Best way is to determine this through testing

    Sean
  • 0 in reply to Sean Bigley
    TI__Genius 10210 points
    Sean,
    We face one issue on motor starting up from zero. If we set a higher USER_MOTOR_MAX_CURRENT (like 15A), motor starts up with a lot of noise. The reference speed is 3000rpm, but it actually is about 1000rpm (The speed feedback actually is not stable on 1000rpm). At that moment, if force angle is disabled, motor will reach 3000rpm without any noise. So the noise comes from force angle, when the speed is about 1000rpm.
    The same test case, if the USER_MOTOR_MAX_CURRENT is 5A, motor works very well.
    During start up, there's only few load. If removing the load, 15A can work well.
    We tried to copy the PI from 5A to 15A, but the result is the same, without any improvement.
    What could be the issue?
    Thanks a lot.
    Br, Jordan