VP20-04 Power Factor Improvement Mechanism of Dual-PM Excited Vernier Machines
Creators: Hong Chen
Yao Meng
Dawei Li
Ronghai Qu and Xinyu Yang
Publisher: name: IEEE
Year: 2025

I.Introduction Taking advantage of the flux modulation effect, permanent magnet vernier machines (PMVMs) exhibit significantly high torque density with multiple working harmonics. However, the conventional PMVMs with only rotor-PMs suffer from a low power factor [1]. This paper comparatively investigates the power factor improvement mechanism of a novel dual-side PMVM (DPMVM) with two-slot-pitch coils featuring high power factor and torque density. The performances are verified by finite element analysis and prototype testing. II.Machine Topology and Operation Principle Fig. 1 (a) and (b) illustrate the proposed DPMVM and its counterpart, which are named topology I and topology II, respectively. For the two DPMVMs, both the stator and rotor have consequent-pole PM arrangement forming doubly salient structures, and the stator slot number and rotor pole number are the same. Due to the different stator-PM arrangements of the two topologies, the modulating tooth number is different, which brings about the differences in the winding pole pair numbers and winding configurations. The operation principles of both DPMVMs are based on the flux modulation effect. The different stator-PM arrangements and winding configurations of the two DPMVMs result in a large difference in the harmonic components of the modulated airgap flux fields, contributing to different inductance and power factor performances of the two DPMVMs. III.Power Factor Evaluation Fig. 2 (a) and (b) compare the phase flux linkages produced by PMs and armatures of the two DPMVMs, respectively. It can be observed that topology I has higher PM flux linkage and lower armature flux linkage than that of topology II. According to Fig.2 (c) and (d), it can be deduced that the power factor of topology I is higher than that of topology II. To verify the forgoing analyses, the power factors of the two topologies are calculated based on FEA and comparatively investigated in Fig.2(e) and (f). The power factor of topology I is much higher than that of topology II. More detailed design considerations and electromagnetic performance comparison results will be presented in the full paper.References: [1]Y. Gao, M. Doppelbauer, R. Qu, etc., IEEE Trans. Ind. Appl., vol. 57, pp. 294(2021).
I.Introduction Taking advantage of the flux modulation effect, permanent magnet vernier machines (PMVMs) exhibit significantly high torque density with multiple working harmonics. However, the conventional PMVMs with only rotor-PMs suffer from a low power factor [1]. This paper comparatively investigates the power factor improvement mechanism of a novel dual-side PMVM (DPMVM) with two-slot-pitch coils featuring high power factor and torque density. The performances are verified by finite element analysis and prototype testing. II.Machine Topology and Operation Principle Fig. 1 (a) and (b) illustrate the proposed DPMVM and its counterpart, which are named topology I and topology II, respectively. For the two DPMVMs, both the stator and rotor have consequent-pole PM arrangement forming doubly salient structures, and the stator slot number and rotor pole number are the same. Due to the different stator-PM arrangements of the two topologies, the modulating tooth number is different, which brings about the differences in the winding pole pair numbers and winding configurations. The operation principles of both DPMVMs are based on the flux modulation effect. The different stator-PM arrangements and winding configurations of the two DPMVMs result in a large difference in the harmonic components of the modulated airgap flux fields, contributing to different inductance and power factor performances of the two DPMVMs. III.Power Factor Evaluation Fig. 2 (a) and (b) compare the phase flux linkages produced by PMs and armatures of the two DPMVMs, respectively. It can be observed that topology I has higher PM flux linkage and lower armature flux linkage than that of topology II. According to Fig.2 (c) and (d), it can be deduced that the power factor of topology I is higher than that of topology II. To verify the forgoing analyses, the power factors of the two topologies are calculated based on FEA and comparatively investigated in Fig.2(e) and (f). The power factor of topology I is much higher than that of topology II. More detailed design considerations and electromagnetic performance comparison results will be presented in the full paper.References: [1]Y. Gao, M. Doppelbauer, R. Qu, etc., IEEE Trans. Ind. Appl., vol. 57, pp. 294(2021).