bldc motor vector control

Discussion in 'General Electronics Chat' started by savage67, Feb 10, 2010.

  1. savage67

    Thread Starter Member

    Oct 3, 2006
    I have to design a sensorless BLDC vector controller for my final thesis. You know, BLDC motor has trapezoidal back emf waveform unlike PMSM which has sinusoidal back emf waveform. there are too many app note on the net but i couldn't find an app note about the sensorless BLDC motor vector control.

    Could you please help me. I need an app note or a final thesis which are include the theory.
  2. VoodooMojo

    Active Member

    Nov 28, 2009
  3. mik3

    Senior Member

    Feb 4, 2008
    Try google scholar.
  4. 3ldon

    Active Member

    Jan 9, 2010
    There is one in every hard drive. try a 30-90 gig segate from back in the day, the last one i found had a 100 page datasheet explaining everything.

    Only thing missing is the vector control as per your specifications, they tend to just use adjustable pulse widths without actually calculating what the pulse width should be.
    For trapezoidal drives the return on investment of a vector controlled drive is minimal because your losses can't be reduced much more than they already are, the only benifit is faster acceleration, and if you are using a BLDC motor as a servo, you're doing it wrong.

    Keep in mind that a 0-60hz vector controlled sensorless induction motor operating at 5KHz PWM needs 50 mips minimum, and if you look hard enough you can find the C code for a commercial product.