VP22-02 Performance Analysis and Optimization of a New Torque Enhanced Permanent Magnet Arc Machine
Creators: Xiangru Lin
Shuhua Fang
Qiangren Xu
Publisher: name: IEEE
Year: 2025

The permanent magnet (PM) arc machines (PMAM) are widely used in large direct-drive scanning system like tanks and large telescopes due to the merits of high reliability and high efficiency [1], [2]. To further improve the torque density of PMAM, some concepts of dual-stator and hybrid-excited PMAM are proposed [3]. However, the structures of these machines are complex and not suitable for large scanning devices. A torque enhanced method by embedding multiple PMs in the machine has been proposed in recent years [4]. But it leads to the increase of PM usage and torque ripple. To address these problems, this paper proposes a new torque enhanced PMAM with flux-reversal and flux-switching PMs. After optimization, the proposal exhibits good electromagnetic performance of high torque with low PM usages. The topology of the proposed PMAM is shown in Fig. 1(a). The flux-reversal and the flux-switching PMs are embedded on the stator teeth. The MFF waveforms are superimposed on each other resulting in larger working harmonics of flux density in air-gap and higher output torque as shown in Fig. 1(a). The proposed machine is comprehensively optimized and analyzed by finite element analysis (FEA) as shown in Fig. 2. The optimization results and the selected point are shown in Fig. 2(a). The back electromotive force (EMF) waveforms are symmetric with a total harmonic distortion of 0.2% at a rated speed of 600 rpm. The cogging torque is 17.6 mNm and the period is. The total average torque is 5.25 Nm at the rated current amplitude of 12 A, which is larger than the sum of the torques excited by flux-reversal (TPM2) and flux-switching (TPM1) PMs because the combination of two types of PMs produces a higher main working harmonics of air-gap flux density. More details about optimization and performance analysis will be addressed in the full paper.References: [1] H. Hu, J. Zhao, X. Liu, et al, IEEE Trans. Magn., vol. 50, no. 11, pp. 1-4, Nov. 2014. [2] Q. Xu, S. Fang, P. Wan, et al, IEEE J. Emerg. Sel. Top. Power Electron., vol. 11, no. 6, pp. 6016-6027, Dec. 2023. [3] Z. Pan, J. Zhao, S. Fang, et al, IEEE Trans Transp. Electrif., vol. 9, no. 2, pp. 2509-2523, June 2023. [4] Y. Meng, S. Fang, Y. Zhu, et al, IEEE Trans Transp. Electrif., early access, doi: 10.1109/TTE.2024.3358392.
The permanent magnet (PM) arc machines (PMAM) are widely used in large direct-drive scanning system like tanks and large telescopes due to the merits of high reliability and high efficiency [1], [2]. To further improve the torque density of PMAM, some concepts of dual-stator and hybrid-excited PMAM are proposed [3]. However, the structures of these machines are complex and not suitable for large scanning devices. A torque enhanced method by embedding multiple PMs in the machine has been proposed in recent years [4]. But it leads to the increase of PM usage and torque ripple. To address these problems, this paper proposes a new torque enhanced PMAM with flux-reversal and flux-switching PMs. After optimization, the proposal exhibits good electromagnetic performance of high torque with low PM usages. The topology of the proposed PMAM is shown in Fig. 1(a). The flux-reversal and the flux-switching PMs are embedded on the stator teeth. The MFF waveforms are superimposed on each other resulting in larger working harmonics of flux density in air-gap and higher output torque as shown in Fig. 1(a). The proposed machine is comprehensively optimized and analyzed by finite element analysis (FEA) as shown in Fig. 2. The optimization results and the selected point are shown in Fig. 2(a). The back electromotive force (EMF) waveforms are symmetric with a total harmonic distortion of 0.2% at a rated speed of 600 rpm. The cogging torque is 17.6 mNm and the period is. The total average torque is 5.25 Nm at the rated current amplitude of 12 A, which is larger than the sum of the torques excited by flux-reversal (TPM2) and flux-switching (TPM1) PMs because the combination of two types of PMs produces a higher main working harmonics of air-gap flux density. More details about optimization and performance analysis will be addressed in the full paper.References: [1] H. Hu, J. Zhao, X. Liu, et al, IEEE Trans. Magn., vol. 50, no. 11, pp. 1-4, Nov. 2014. [2] Q. Xu, S. Fang, P. Wan, et al, IEEE J. Emerg. Sel. Top. Power Electron., vol. 11, no. 6, pp. 6016-6027, Dec. 2023. [3] Z. Pan, J. Zhao, S. Fang, et al, IEEE Trans Transp. Electrif., vol. 9, no. 2, pp. 2509-2523, June 2023. [4] Y. Meng, S. Fang, Y. Zhu, et al, IEEE Trans Transp. Electrif., early access, doi: 10.1109/TTE.2024.3358392.