A novel dual-sided PM variable flux memory machine

This paper proposes a novel dual-sided permanent magnet memory machine (DSPM-MM) by combing the distinct advantages of “high torque density” of conventional rotor-PM machine and “convenient online PM flux control” of stator-PM MM. In the proposed design, the consequent-pole NdFeB PMs are placed in the rotor, whereas the low coercive force (LCF) PMs are mounted between the adjacent stator teeth to enable flexible air-gap flux adjustment. Meanwhile, since the LCF PMs can be either remagnetized or demagnetized bidirectionally by a current pulse, the associated flux-weakening copper loss is eliminated, and hence, the proposed DSPM-MM can maintain high efficiency operation over a wide operating range. The machine topology and operating principle are introduced and addressed from the perspective of the nonlinear hysteresis behavior of LCF PMs as well as dual flux modulation effect, respectively. Then, the electromagnetic characteristics of the proposed machines having various available rotor poles are investigated and compared. The feasibility of the proposed design is validated by both finite element and experimental results.