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The partitioned stator switched-flux permanent magnet (PM) (SFPM) (PS-SFPM) machine is a novel stator-PM machine in which PMs and armature windings are separately placed in two different stators. Compared with the conventional SFPM machine with a single stator in which both PMs and armature windings are located, the PS-SFPM machine can generate higher torque density due to the utilization of the machine's inner space. In this paper, the magnetic gearing effect in the PS-SFPM machine is investigated in terms of air-gap field harmonics based on a simple magnetomotive force (MMF)-permeance model. It is found that the PS-SFPM machine is one type of magnetically-geared machine, in which the modulations of rotor iron pieces to the open-circuit PM and armature reaction fields are similar to those found in the magnetic gear and the conventional magnetically geared machine. The pole-pair numbers and rotating speeds of the air-gap field harmonics obtained by the MMF-permeance model are verified by finite element (FE) analysis. More than 93% of the average electromagnetic torque is contributed by the main air-gap field harmonics having pole-pair numbers (2i - 1)\boldsymbol p PM and \rm| N\rm{r} \,\pm \, (2i-1)pPM| ( i = 1,2,3) in a PS-SFPM machine with pPM-pole-pair PMs and Nr-rotor-pole. A prototype machine is fabricated and tested to verify the FE analysis. [ABSTRACT FROM PUBLISHER]

This paper first investigates the flux-weakening control performance of two types of partitioned stator-switched flux permanent-magnet (PM) (PS-SFPM) machines and then proposes a novel mechanical flux-weakening technique. The PS-SFPM machine topologies, operation principles, and flux-weakening control method are described. In addition, it is shown that by mechanically varying the relative position of two stators of the PS-SFPM machine, the PM flux linkage can also be varied, and hence, it can provide improvement in the speed range and torque capability. The optimal relative mechanical angle is derived to enable the maximum torque capability and reduce or even avoid the flux-weakening current injected by the inverter. The proposed technique is verified by three-dimensional (3-D) finite-element (FE) analyses and experiments on the prototype machines. [ABSTRACT FROM AUTHOR]

This paper proposes a partitioned stator variable flux reluctance machine (PS-VFRM) in which field and armature windings are placed on two separate stators. The influence of different stator/rotor-pole combinations on the electromagnetic performance is examined using finite-element analysis. Candidate designs maximize the average electromagnetic torque. Compared against the conventional single stator VFRM, the proposed PS-VFRM is shown to provide 24.6% and 12.7% increases in torque density and efficiency, respectively. The static electromagnetic performance is validated using experimental prototypes. [ABSTRACT FROM PUBLISHER]

The partitioned stator (PS) machine adopts two stators to allocate windings and permanent magnets (PMs) separately, increasing the space for PMs as well as armature coils to boost the electromagnetic torque and improving the thermal condition of PMs. In this paper, the PS switched-flux PM (PS-SFPM) machine and the PS flux reversal PM (PS-FRPM) machine are proved to inherently share the same operating principle and similar machine topology but with interior PM (IPM) and surface-mounted PM stators, respectively. Furthermore, four globally optimized PS machines with different inner stator topologies are compared in terms of back EMF, cogging torque, electromagnetic torque, torque per PM volume, and flux-weakening capability. The results reveal that the spoke-shaped IPM (IPM-spoke) inner stator exhibits the highest back EMF and hence the highest average torque, while the I-shaped IPM (IPM-I) stator has the best flux-weakening capability, and the V-shaped IPM (IPM-V) produces the highest torque per PM volume. Furthermore, four machines are redesigned with the same PM usage volume, and the results show that the PS-SFPM machine still exhibits the highest back EMF as well as torque although with sacrificed advantages. The finite-element analyses and experiments are used to confirm the predictions. [ABSTRACT FROM AUTHOR]

A novel type of partitioned stator switched flux permanent magnet (PS-SFPM) machine with either single-layer or double-layer windings is developed in this paper. The proposed PS-SFPM machines have two stators, which separately accommodate the armature windings and the PMs, and between which is the rotor made of iron pieces, while the number of stator poles with PMs may be equal or half of that with armature windings. All the machines are optimized under fixed copper loss for maximum average torque by genetic algorithm. Their electromagnetic performances are compared, such as open-circuit flux-linkages and back-electromotive forces (EMFs), cogging torque, static torque waveforms, average torque against current, PM utilization ratio, and flux-weakening performances. The results show that due to more PM usage and higher open-circuit back-EMF, the PS-SFPM machines having the number of stator poles with PMs the same as that with armature windings exhibit higher average torque, irrespective of the winding topologies, either single-layer or double-layer windings. However, the single-layer winding PS-SFPM machines having the number of stator poles with PMs half of that with armature windings have the best PM usage and the highest ratio of average torque to PM volume, as well as good flux-weakening capability. A prototype machine is manufactured and tested to validate the analyses. [ABSTRACT FROM PUBLISHER]

In this paper, novel partitioned stator doubly salient permanent magnet (PS-DSPM) machines with separated PM excitation and armature windings are proposed. Compared with conventional DSPM machines with single stator in which PMs are inserted in the yoke and windings are arranged on the teeth, the proposed PS-DSPM machine has two stators with PMs and windings located separately. Two sets of PS-DSPM machines, i.e., PS-DSPM-I and PS-DSPM-II machines, are proposed based on the conventional DSPM-I and DSPM-II machines in which the PMs are located on the stator yoke with intervals of every number of phases and every stator pole, respectively. The electromagnetic performance including back electromotive force (EMF) and torque characteristics of the proposed PS-DSPM machines are analyzed and compared with those of the conventional DSPM machines based on the optimal designs for the highest average electromagnetic torque by finite-element (FE) analysis in this paper. FE results show that the proposed PS-DSPM-I and PS-DSPM-II machines exhibit 8.49% and 207% higher torque density than the conventional DSPM-I and DSPM-II machines with same copper loss, respectively. The influence of main design parameters on the average electromagnetic torque in the proposed PS-DSPM machines is investigated, together with the conventional DSPM machines. A prototype machine of PS-DSPM-II is manufactured and tested to verify the FE analysis. [ABSTRACT FROM AUTHOR]