Field weakening capability of 12-stator/10-rotor-pole variable flux reluctance machines

Variable flux reluctance machines (VFRMs) are viable candidates for automotive applications. This paper investigates the field weakening capability of a 12/10 VFRM. Starting with voltage and toque equations, the paper reveals the relationship between torque-speed characteristics and the current arrangement (slot division) of both DC-field and armature windings. The method for expanding the working envelope by tuning DC or AC currents is discussed for different slot divisions. The results are validated by 2D finite element analysis.