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I'm working on an algorithm to control a BLDC motor with 56 poles and 63 slots. I'm using trapezoidal control. By employing usual switching sequence (CA - CB - AB - AC - BC BA) I'm missing one step in the six step commutation. Where am I going wrong?

I found above switching sequence is referenced to the standard winding sequence(ABCABC). There are winding sequence table available for upto 20 pole BLDC. If I get the correct winding sequence, I can edit my algorithm to make positive torque without missing any steps.

  • Can anyone provide the winding sequence information for 56 pole 63 slot bldc?
  • Is there any standard text books I can refer regarding the practical BLDC motor construction?

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Vivek Vijayan
  • 75
  • 6

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From these two answers you can get some of the background info...

How to determine brushless DC (BLDC) winding pattern, based on poles and slots?

Finding number of pole pairs in a BLDC motor

Neither of them covers your precise use case. However, as 63/9 = 7 and 56/8 = 7, I would suggest you take the 9 slot(tooth) 8 pole winding from those diagrams (source : "Home built electric motors") as a starting point and replicate it 7 times round the circumference.