Effect of Slot/Pole Combination on the Performance of Complementary-Rotor Doubly Salient Permanent Magnet Motors

This paper proposes three new arrangements for double rotor yoke-less stator-PM motors. These structures are based on biased-flux PM motor and the inner rotor mechanically couples with the outer rotor. This increases the output torque by increasing the effective length of force vector. Moreover, these rotors are positioned in a way that produces the maximum amount of average torque. Using the flux modulation method, the flux density distribution of these structures are analyzed. It has been demonstrated that the space harmonics of flux density (or the pole-pairs of no-load flux density) has a definitive impact on power factor of the proposed structures. In order to deepening the analysis, the pole-pairs of the structures are segregated into different groups according to their rotational speed. To verify the analysis, ANSYS MAXWELL software package is used to analyze the no-load and full-load performance of the structures. In this study, the no-load flux patterns, induced voltages, torque profiles, and efficiencies are calculated along with the connection of power factor and torque density of the topologies.