Investigation of Magnetic Equivalent Circuit Modeling Approaches for an Asymmetric and Unbalanced Winding Permanent Magnet Motor

This paper presents magnetic equivalent circuit (MEC) modeling approaches for an unbalanced and asymmetric winding 39-slot 12-pole permanent magnet (PM) motor. Such unconventional slot-pole configuration has certain benefits over conventional integral slot PM motors such as low cogging and torque ripple, and low rotor manufacturing cost. This slot-pole combination leads difficulty in analytical modeling since the motor symmetry is different from conventional PM motors. Simpler MEC modeling approaches would be useful in designing such motors with unconventional combinations. Four different MEC modeling approaches are investigated in this paper for an experimentally verified 39-slot 12-pole motor. Benefits and drawbacks of each approach are presented. No-load and on-load results obtained from MEC modeling approaches are compared with the finite element analysis (FEA) and test data to illustrate the benefits of the modeling approaches.