Winding Characteristics and Magnetization State Regulations of Variable Flux Memory Machines With Segregated Distributed Windings

The variable flux memory machine with segregated multiple three-phase windings is investigated, with particular reference to its winding characteristics and magnetization state (MS) regulations. The overlapped distributed windings are separated into multiple three-phase winding sets, with each set nonoverlapping, which contributes to the independent relationship between the winding set and corresponding permanent magnet pole-pairs. Consequently, the single winding set can independently complete the MS regulation, and thus the overall current requirement is reduced. Moreover, it is revealed that the amplitude of de-/remagnetizing magnetomotive force (MMF) with single-winding-set operation is actually higher than that with multiple-winding-set operation thanks to the asymmetric winding layout, resulting in enhanced de-/remagnetizations and thus further reduced de-/remagnetizing currents. The winding function, MMF distribution, inductance, and torque of the machine are analyzed, and intentional MS regulations with different methods are compared. A prototype machine is fabricated and tested for experimental validation.