Consequent-Pole Hybrid Excitation Brushless Wound Field Synchronous Machine With Fractional Slot Concentrated Winding

In this paper, a new consequent-pole hybrid excitation brushless wound field synchronous machine (CpHE-BL-WFSM) with fractional-slot concentrated winding is proposed. The proposed machine inherits the features of a brushless excited topology in which a rotor field is excited through an additional sub-harmonic magnetomotive force generated by the stator winding arrangement. In conventional BL-WFSMs, the zero starting torque and relatively low efficiency compared to that of permanent magnet synchronous machines (PMSMs) makes it difficult to replace expensive PMSMs in low- and medium-power applications. The advantages of the proposed machine are improved efficiency, improved starting torque, and high electromagnetic torque as compared to conventional brushless machines. A 2-D finite-element analysis is conducted to compare the proposed machine with the conventional BL-WFSM topologies. The results reveal that the proposed machine topology exhibits greater efficiency, improved starting torque, high average torque, and improved torque density.