Accurate computation of electromagnetic forces in switched reluctance motors

The theory and practice of electromagnetic force calculations are briefly summarized. Different factors causing numerical errors of magnetic forces are systemically analyzed, and the methods to avoid those errors in Maxwell's stress tensor method are discussed. It is suggested that three layers of finite elements in the air-gap of electrical machines, instead of two element layers used by many magnetic experts, be used for accurate computations. An example of the force computation and torque test of the SRM is presented to validate the theoretical analysis in the paper.

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