Calculation of gig air-gap magnetic field in poly-phase multi-pole BLDC motor

If the air-gap is small, the computing error can be neglected when the conventional formulas are used to calculate the air-gap magnetic field. But they will result in a great error for the calculation of the air-gap magnetic field of a motor with a big air-gap. The magnetic potential superimposed method is hereby a more precise calculation solution for a motor with a big air-gap. The validity of the above method is verified, for the calculation result by the proposed method is consistent with both the result derived from the finite element method (FEM) and the experimental waveform.