A stator-PM consequent-pole vernier machine with hybrid excitation and DC-biased sinusoidal current

Abstract

This paper proposes a novel hybrid excitation vernier permanent magnet machine (HE-VPM). The characteristics of the proposed machine are: 1) The PMs are embedded in the stator teeth, which is helpful for heat dissipation; 2) the rotor is salient structure without PMs and windings, which ensures the reliability of high speed running; 3) The non-overlapping concentrated winding shortens the end-winding, and improves the torque density, 4) Only half of the stator teeth possess PMs, and the total amount of PMs are decreased; 5) The DC current are injected to the armature coils, therefore, the exciting field can be adjusted flexibly. In this paper, the electromagnetic performance, including back-EMF, torque, etc. are analyzed with finite element analysis (FEA). The results show that the proposed machine exhibits flexible field adjustment capability, which may be suitable for applications requiring wide speed range operation. Besides, it is found that, compared with fed with the existing pure sinusoidal phase current, higher torque can be obtained with DC-biased phase current under constant stator copper loss.