Investigations of Toroidal Winding Doubly Salient Reluctance Machines with Sinusoidal Excitations

A novel three-phase doubly salient reluctance machine (DSRM) with both toroidal windings (TWs) and sinusoidal excitations are proposed and investigated. The machine topology and winding characteristics are introduced. The operating principle and torque production mechanism are elaborated, in which the magnetic gearing effects are revealed. Moreover, the equivalent winding pole-pair is defined to facilitate the winding factor calculations, based on which the slot/pole number combination can be carefully selected to obtain the high amplitudes of effective winding magneto-motive forces and high torques. Moreover, the effects of critical design parameters are analyzed and the machines are optimized. Based on theoretical and finite element analyses, the proposed DSRMs are evaluated and compared with the diverse DSRMs adopting either concentrated windings (CWs) or distributed windings (DWs). The results reveal that the proposed TWs not only contribute to higher torques than the CWs but also feature with shorter end-windings as well as lower copper losses than the DWs. The torque ripples are also alleviated. Finally, a DSRM prototype with TWs is manufactured and tested for validations.