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InstaSPIN algorithm & BLDC motor control

Dinesh Guleria
Intellectual 515 points

Hi Ti Team,

Our Motor controller performance depends on how accurately we have measured the Motor parameters. 
But Load inertia & viscous damping are some factors which we cannot measure accurately & they varies from time to time & depending upon the operating condition.

I read in blog that TI have Insta-spin algorithm & software part of which is FAST which can calculate motor parameters.

Please suggest on following points from my side.

  1. How much time FAST takes to compute these motor parameters ?
  2. Running FAST before the actual FOC software algorithim will it effect the performance to end consumer ? Or fast will run motor for very small amount of time which is not visible to end consumer ?
  3. Suppose i have a E-Rikshaw which is using BLDC motor to run the vehicle. Now in this vehicle there can be 2/3/4 person sitting at a time when it starts so Inertia is different for each case ? So how to handle this type of case ? Do you recommend using instaspin FAST algorithm to calculate Inertia & other motor parameter every time when vehicle starts from Zero speed shop.indiantradebird.org/.../0_ba6d9190.jpg
  4. TI processor C2000 uses IQ Math library to handle floating point numbers. Using Floating point library or hardware floating point . what exact advantage we have in terms of Control theory. One i know is using hardware floating point unit is faster & can effect time shift property of laplace transform which effects the phase shift. Apart from this ?
  5. TI is having Processors for motor control & well tested software SVM, PI , FAST etc. So being a product development company if some one want to make motor control drive then what exactly they do ? Means they only tune (motor parameters in header file) your already existing software to drive motor & concentrate on application development part ? So there control system skills are never tested ?

Please suggest.

Regards,
Dinesh

  • 0
    TI__Guru** 115440 points
    You can find more detail description in InstaSPIN user guide (SPRUHJ1G), and please find the short answer as below.

    1.How much time FAST takes to compute these motor parameters ?
    A: The time is based on control frequency and motor type, about 90s for PMSM and 15KHz control frequency.

    2.Running FAST before the actual FOC software algorithim will it effect the performance to end consumer ? Or fast will run motor for very small amount of time which is not visible to end consumer ?
    A: FAST is a sensorless FOC algorithm for rotor angel estimation which is TI IP in ROM.

    3.Suppose i have a E-Rikshaw which is using BLDC motor to run the vehicle. Now in this vehicle there can be 2/3/4 person sitting at a time when it starts so Inertia is different for each case ? So how to handle this type of case ? Do you recommend using instaspin FAST algorithm to calculate Inertia & other motor parameter every time when vehicle starts from Zero speed shop.indiantradebird.org/.../0_ba6d9190.jpg
    A: Only do this without load.

    4.TI processor C2000 uses IQ Math library to handle floating point numbers. Using Floating point library or hardware floating point . what exact advantage we have in terms of Control theory. One i know is using hardware floating point unit is faster & can effect time shift property of laplace transform which effects the phase shift. Apart from this ?
    A: You can find more detail information in IQmath guide. IQmath implement virtual float point functions on a fixed point controller, not a real float point.

    5.TI is having Processors for motor control & well tested software SVM, PI , FAST etc. So being a product development company if some one want to make motor control drive then what exactly they do ? Means they only tune (motor parameters in header file) your already existing software to drive motor & concentrate on application development part ? So there control system skills are never tested ?
    A: InstaSPIN is a modular design, you can use some or all InstaSPIN-FOC modules based on your application. You only need to change motor parameters in user.h if you are using full InstaSPIN-FOC for some applications.
  • 0 in reply to Yanming Luo
    Intellectual 515 points

    Hello Yanming,

    Thanks for your reply.

    Regards,

    Dinesh