Analysis and Experiment of a Dual Stator/Rotor PM and Winding Flux Modulated PM Machine

In this article, a high torque density flux modulated permanent magnet machine topology with dual permanent magnets and dual armature windings (DMDA-FMPM) is proposed. The most notable feature of DMDA-FMPM is that both stator and rotor parts consist of PMs and armature windings so that a single air gap and a simple structure are kept. Moreover, both the PMs can interact with both the windings to produce four torque components, and the output torque on the shaft is the superposition of these four torque components. Consequently, extremely high torque is expected. This paper firstly introduces the topology and main drive circuit of DMDA-FMPMs. Then the basic operation principle and slot/pole combination equation are illustrated, taking the proposed topology as an example. Afterward, the electromagnetic performance, including flux line distribution, flux density, back electromotive force (EMF), torque quality, and power factor, is analyzed by finite element analysis (FEA). Besides, the fault-tolerance of windings failure and PM demagnetization is discussed. A prototype is designed and tested to verify the proposed DMDA-FMPM. The experimental results match well with the FEA and theoretical analysis. DMDA-FMPM has excellent torque performance and fault-tolerant capability. Finally, the possible applications, operating modes, advantages, and drawbacks are discussed comprehensively.