How to commutate the BLDC motor using quadrature encoder

Discussion in 'The Projects Forum' started by ep.hobbyiest, Jan 2, 2016.

  1. ep.hobbyiest

    Thread Starter Member

    Aug 26, 2014
    91
    0
    Hi,
    Is it possible to commutate the bldc motor using quadrature encoder?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    It was originally done with 3 hall sensors, now the normal way is commutation tracks on the quadrature encoder, in some cases it can be done by the controller initially exercising the motor and using quadrature and current feedback to locate the field positions, from then on the encoder is used to commutate.
    Max.
     
  3. ep.hobbyiest

    Thread Starter Member

    Aug 26, 2014
    91
    0
    you meant to say, we can do. We just have to compare the the count of encoder. Like
    lets take 1 revoulution is of 1000 count.
    1000/3=333

    if i get 333 then i should commutate the A coil and if it 666 then B coil and if it 999~1000 then C coil. Is it correct?
     
  4. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    If using the encoder, then you need to initially find the relative position of the poles by exercising the motor initially to do this, then you also need to know or find the pole count.
    Then the encoder position is used to commutate, I have not used this method personally but some drive manuf. have.
    Search Microchip site, they have a few examples of BLDC motor control.
    Max.
     
    Last edited: Jan 3, 2016
    ep.hobbyiest likes this.
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