Analysis of Flux-Reversal Permanent-Magnet Machines With Different Consequent-Pole PM Topologies

Abstract

This paper comprehensively studies the electromagnetic performance of flux reversal permanent magnet (FRPM) machines with different consequent-pole PM (CPM) topologies. Four CPM topologies are firstly introduced and classified by different numbers of PM pieces and PM locations on stator teeth. Then, the distribution and working harmonics of air-gap flux density of each CPM topology are analyzed and compared, and the CPM topology with the highest torque density is identified. The influence of critical design parameters on machine performance is also parametrically investigated. By comparing the torque performance of CPM topologies with their surface-mounted PM (SPM) counterparts, the advantages of CPM topologies, i.e. torque improvement and magnet volume reduction, are clearly revealed. Four FRPM prototypes are manufactured and tested to verify the analyses.

Analysis of Consequent-Pole Flux Reversal Permanent Magnet Machine With Biased Flux Modulation Theory

“…It suggests that the winding pole pair number Pa of the developed CP-FRM is the same as that of the vernier machine with rotor pole pair number of "Nr" [21]. In other words, the CP-FRM shares identical winding configuration of conventional rotor PM machine, which is quite different from switched flux machines and doubly salient machines.…”

“…It is worth mentioning that the coil flux linkage is non-sinusoidal due to the unbalanced magnetic fluxes from the PM and iron poles. Nevertheless, the resultant phase flux linkage is still sinusoidal and symmetrical by connecting individual coils of the same phase in opposite directions [21], as shown in Fig. 13.…”

“…For instance, in the case of "i=1", it indicates that the modulated air-gap fields derived from the fundamental PM harmonic are considered, and the pole pair numbers of the resultant rotating air-gap harmonics can be obtained based on (22) and (23), i.e., 5 and 17, respectively. Subsequently, the torque contributions due to 5 th and 17 th air-gap field harmonics can be computed based on (21). The key parameters and the torque components due to each air-gap field harmonic are computed and listed in Table II in order to quantify and provide a powerful insight for the torque contribution.…”

“…Based on the SPM-FRM-I [7]- [17], a corresponding CP configuration is presented in [20] [21], as shown in Fig. 2(a).…”

“…2(a). In [21], the influence of different CP arrangements on the electromagnetic performance of CP-FRMs is investigated, which suggests the torque capability can be further enhanced by selecting an appropriate CP structure. Besides, when multiplying the PM segments per stator pole, several alternative CP-FRMs are developed so as to further improve the torque density [22].…”