• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 32 subscribers
  • Views 695 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Expected efficiency increase when implementing Field Oriented Control

Andrew Phillips1
Prodigy 40 points

I'm designing a motor controller design for a BLDC and I'm trying to decide if its worth the effort to move from a commutation table to space vector modulation.  The main thing I'm interested in is the expected efficiency increase.  Everything I've read says that using FOC increases system efficiency but I haven't found any actual numbers to support this.  Any one have any idea?

  • 0
    TI__Guru** 114905 points
    Hi Andrew,

    We have asked our FOC experts to comment. They should reply soon.
  • 0
    TI__Guru** 119680 points
    this is a tricky topic which I've posted about several times before either here or on the InstaSPIN forum

    from a purely peak output power / input power standpoint, you can argue that a well current regulated 6-step Trapezoidal commutation can deliver more efficiency since it can deliver more output power.

    FOC starts chipping away at the power usage by reducing torque ripple, maximizing efficiency of the magnetic interactions, and giving better dynamic performance. the more dynamic the application (quickly changing loads or torque/speed commands) the more incremental gains you would see from FOC.

    but many of the times the efficiency is going to depend much more on the motor and power stage design itself, not necessarily the control scheme.

    so, it really depends on use case. in a low dynamics application FOC doesn't buy you much in terms of efficiency and you really aren't using many of the system benefits. but in a high dynamics application you can see some overall gains of a few points up to maybe 15%.


    BTW - many of the times when you see FOC efficiency claims it is specific to induction motor drivers, where 3-ph FOC significantly increases efficiency vs. 1 or 3-ph volts per hertz style control.