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MCF8316AEVM: the motor speed exceeds the target speed

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Prodigy 60 points
Part Number: MCF8316AEVM
Other Parts Discussed in Thread: MCF8316A

Tool/software:

Hello.
I am having a problem when I am debugging a brushless DC motor using the MCF8316A EVM. After I start running the motor every time, the motor speed exceeds the target speed and then drops back down to the target speed. For example, if I set it to 3600 rpm, the motor will reach 3800 rpm every time and then drop back down to 3600 rpm. If I present this effect to the customer, it will be passed over. Therefore, I would like to know if it is possible to set up a setting in motor studio so that the motor will not increase after it reaches the target speed, how do I set it up?
Sorry I'm not very good with motor studio, I would appreciate if you could guide me with pictures.

  • 0
    TI__Genius 16265 points

    Hi,

    This is a overshoot effect, to make it better we need to tune the Speed Loop KP, KI values.

    The device runs two loops when in Speed Loop mode, the inner most loop is current loop which runs ate higher bandwidth and outer loop is the speed loop which si generally slower with respect to current loop.

    User can reduce current loop gain also.

    Other than working with closed loop we can look at open loop to closed loop hand off, what is the hand off method and at what speed hand off happens?

    What is the closed loop acceleration value? If verify then reduce it little bit until it meets startup time requirement.

    Thanks and Best Regards

    Venkatadri S

  • 0 in reply to Venkatadri Shantaram84961
    TI__Genius 16265 points

    Hi 

    Do you have any update on this? 

    Thanks and Best Regards

    Venkatadri S