VP5-10 Investigation of Different Pole Configurations in New Asymmetric Permanent Magnet Synchronous Reluctance Machines
Creators: Akbar Mohammadi Ajamloo
Aghil Ghaheri
Mohamed N. Ibrahim
Peter Sergeant
Publisher: name: IEEE
Year: 2025

Permanent Magnet (PM) machines have been widely used in various applications due to their high torque density and efficiency. However, high price of rare-earth PMs and their market instability have raised concern regarding wide-spread usage of PM machines [1]. PM-assisted Synchronous Reluctance Machines (PMaSynRMs) emerge as a good solution in reducing the PM usage due to high contribution of the reluctance torque in the total torque [2]. However, two limitations prevent more efficient utilization of PMs: 1) the theoretical displacement between the reluctance and magnet torque components by 45 electrical degrees (E.D) [3], 2) the coupled design of the PM and flux barrier shapes [4]. This study presents and compares different configurations of a new family of Asymmetric PMSynRM (APMSynRM) with the conventional topology, all shown in Fig. 1, categorized based on the number of poles (p). In the proposed APMSynRM designs, two types of poles are utilized: interior PM (IPM) poles and SynRM poles. This allows for the independent design of flux barriers and PMs, facilitating optimal design of rotor geometry. Additionally, the d-q axes of the SynRM poles (dr-qr) are strategically displaced by β degrees relative to the d-q axes of the IPM poles (dm-qm). This ensures peak electromagnetic torque from each pole aligns at the same current angle, maximizing the utilization of rotor pole capacity. A comparative study is conducted between the proposed and conventional topologies, as presented in Table I, while keeping the copper loss, outer diameter, length, and PM volume fixed. The rotor configurations have been optimized to achieve maximum torque. Among the designs with the highest torque, the design with the lowest torque ripple is selected as the optimal design. The results show that the proposed APMSynRM designs achieve higher maximum torque (Tmax) compared to conventional PMaSynRMs. Additionally, most asymmetric designs demonstrate relatively lower torque ripple. However, some asymmetric configurations exhibit unbalanced magnetic pull (UMP), which requires consideration.References: [1]. B. Poudel, E. Amiri, P. Rastgoufard, IEEE Transactions on Magnetics., Vol. 57, p.1-19 (2021) [2]. K. Tawfiq, E. El-Kholy, M. Ibrahim, IEEE Transactions on Magnetics., Vol. 57, p.1-11 (2021) [3]. Z. Zhu, Y. Xiao, IEEE Transactions on Magnetics., Vol. 58, p.1-10 (2021) [4]. A. Nobahari, A. Vahedi, R. Nasiri-Zarandi, IEEE Transactions on Energy Conversion., Vol. 37, p. 989-998 (2021)
Permanent Magnet (PM) machines have been widely used in various applications due to their high torque density and efficiency. However, high price of rare-earth PMs and their market instability have raised concern regarding wide-spread usage of PM machines [1]. PM-assisted Synchronous Reluctance Machines (PMaSynRMs) emerge as a good solution in reducing the PM usage due to high contribution of the reluctance torque in the total torque [2]. However, two limitations prevent more efficient utilization of PMs: 1) the theoretical displacement between the reluctance and magnet torque components by 45 electrical degrees (E.D) [3], 2) the coupled design of the PM and flux barrier shapes [4]. This study presents and compares different configurations of a new family of Asymmetric PMSynRM (APMSynRM) with the conventional topology, all shown in Fig. 1, categorized based on the number of poles (p). In the proposed APMSynRM designs, two types of poles are utilized: interior PM (IPM) poles and SynRM poles. This allows for the independent design of flux barriers and PMs, facilitating optimal design of rotor geometry. Additionally, the d-q axes of the SynRM poles (dr-qr) are strategically displaced by β degrees relative to the d-q axes of the IPM poles (dm-qm). This ensures peak electromagnetic torque from each pole aligns at the same current angle, maximizing the utilization of rotor pole capacity. A comparative study is conducted between the proposed and conventional topologies, as presented in Table I, while keeping the copper loss, outer diameter, length, and PM volume fixed. The rotor configurations have been optimized to achieve maximum torque. Among the designs with the highest torque, the design with the lowest torque ripple is selected as the optimal design. The results show that the proposed APMSynRM designs achieve higher maximum torque (Tmax) compared to conventional PMaSynRMs. Additionally, most asymmetric designs demonstrate relatively lower torque ripple. However, some asymmetric configurations exhibit unbalanced magnetic pull (UMP), which requires consideration.References: [1]. B. Poudel, E. Amiri, P. Rastgoufard, IEEE Transactions on Magnetics., Vol. 57, p.1-19 (2021) [2]. K. Tawfiq, E. El-Kholy, M. Ibrahim, IEEE Transactions on Magnetics., Vol. 57, p.1-11 (2021) [3]. Z. Zhu, Y. Xiao, IEEE Transactions on Magnetics., Vol. 58, p.1-10 (2021) [4]. A. Nobahari, A. Vahedi, R. Nasiri-Zarandi, IEEE Transactions on Energy Conversion., Vol. 37, p. 989-998 (2021)