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

Abstract

The variable flux memory (VFM) 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 non-overlapped, which contributes to the independent relationship between the winding set and corresponding permanent magnet (PM) 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/re-magnetizing magneto-motive force (MMF) with single winding set operation is actually higher than those with multiple winding sets operation thanks to the asymmetric winding layout, resulting in the enhanced de/re-magnetizations and thus the further reduced de/re-magnetizing 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 validations.