Closed-Form Solution for the Slot Leakage Inductance of Tooth-Coil-Winding Permanent Magnet Machines

This paper presents a methodology for the analytical computation of the slot leakage inductance of tooth-coil winding permanent magnet synchronous machines. Generalized equations for the slot leakage inductance of the whole phase are derived, suitable for several slot-pole combinations, and meant to be used during the machine design stage. For simplicity, self- and mutual-inductance components are formulated using the classical method with detailed permeance determination for both horizontal and vertical distribution of coil sides in the slots, considering a straight-line path for the flux leakage. Several slot-pole combinations were simulated by means of the finite element (FE) method in order to validate the analytical equations in both approaches, FE and analytical, showing adequate concordance.