VP20-02 Investigation of Vernier Arc Machines with IPM Rotor Structures
Creators: Yao Meng
Mingchen Yang
Hong Chen
Shuhua Fang and Xingzhen Bai
Publisher: name: IEEE
Year: 2025

I. Introduction Due to the merits of simple structure and high torque density, vernier permanent magnet arc machine (VPMAM) has been an appealing choice in large telescope drive[1]. In this paper, four VPMAMs with different rotor topologies are designed and comprehensively compared to provide a basic design reference of designing VPMAM. Meanwhile, a preferable candidate can also be selected based on the analysis results. II. Machine Topology and Operation Principle As an example of the investigation, the 12 stator-slot /17 rotor-pole-pair VPMAMs were considered. In Fig.1, four VPMAMs with different rotor topologies are presented, including a conventional surface-mounted PM rotor, a consequent-pole PM rotor, a spoke array PM rotor and a V-shaped PM rotor, which are named as Type I, Type II, Type III, and Type IV, respectively. To make a fair comparison, all the design parameters of each machine are identical except for the PM arrangements. For all four VPMAMs, the magnetomotive force produced by PMs is modulated by the stator slot to produce rich working harmonics. Because of the different arrangement of PMs, the PM magnetomotive forces are different, so the harmonic type and amplitude are also affected, which will be discussed in the full paper. III. Electromagnetic Performance Comparison The no-load air-gap flux densities of the four topologies are compared in Fig. 2(a) and(b). It can be found that the air-gap flux density harmonics of Type III are more abundant, in which the 5th and 17th have the higher amplitudes. Fig. 2(c) shows the open-circuit phase flux linkages. It shows that Type IV has a larger peak-to-peak value than other machines. The back EMFs of four machines are compared in Fig.2(d). It can be seen that Type III can achieve the maximum back EMF. The cogging torques of four machines are compared in Fig. 2(e), where the peak values of cogging torque in Type II is maximum and the Type IV is the minimum. The steady-state average torque under the same electrical load is compared in Fig.2(f). It can be observed that the torque capability of Type III is much better than others. More detailed design considerations and electromagnetic performance comparison results will be presented in the full paper.References: [1] P. M. Tlali, R. J. Wang, S. Gerber, IEEE Trans. Ind. Appl., vol. 56, no. 3, pp. 2570–2579(2020).
I. Introduction Due to the merits of simple structure and high torque density, vernier permanent magnet arc machine (VPMAM) has been an appealing choice in large telescope drive[1]. In this paper, four VPMAMs with different rotor topologies are designed and comprehensively compared to provide a basic design reference of designing VPMAM. Meanwhile, a preferable candidate can also be selected based on the analysis results. II. Machine Topology and Operation Principle As an example of the investigation, the 12 stator-slot /17 rotor-pole-pair VPMAMs were considered. In Fig.1, four VPMAMs with different rotor topologies are presented, including a conventional surface-mounted PM rotor, a consequent-pole PM rotor, a spoke array PM rotor and a V-shaped PM rotor, which are named as Type I, Type II, Type III, and Type IV, respectively. To make a fair comparison, all the design parameters of each machine are identical except for the PM arrangements. For all four VPMAMs, the magnetomotive force produced by PMs is modulated by the stator slot to produce rich working harmonics. Because of the different arrangement of PMs, the PM magnetomotive forces are different, so the harmonic type and amplitude are also affected, which will be discussed in the full paper. III. Electromagnetic Performance Comparison The no-load air-gap flux densities of the four topologies are compared in Fig. 2(a) and(b). It can be found that the air-gap flux density harmonics of Type III are more abundant, in which the 5th and 17th have the higher amplitudes. Fig. 2(c) shows the open-circuit phase flux linkages. It shows that Type IV has a larger peak-to-peak value than other machines. The back EMFs of four machines are compared in Fig.2(d). It can be seen that Type III can achieve the maximum back EMF. The cogging torques of four machines are compared in Fig. 2(e), where the peak values of cogging torque in Type II is maximum and the Type IV is the minimum. The steady-state average torque under the same electrical load is compared in Fig.2(f). It can be observed that the torque capability of Type III is much better than others. More detailed design considerations and electromagnetic performance comparison results will be presented in the full paper.References: [1] P. M. Tlali, R. J. Wang, S. Gerber, IEEE Trans. Ind. Appl., vol. 56, no. 3, pp. 2570–2579(2020).