VP4-09 A Novel Modular Consequent-Pole PMSM with Low Rotor Losses and High-Power Factor
Creators: Xinlei Zheng
Heyun Lin
Xianxian Zeng
Publisher: name: IEEE
Year: 2025

Large-scale permanent magnet synchronous machines (PMSMs) with high performance and low cost are urgently required in ship propulsion, power generation and other fields. Consequent-pole PMSMs (CP-PMSMs) with fractional slot concentrated winding (FSCW) have drawn increasingly more attention [1-3]. However, rich non-working harmonics in their armature reaction magnetic field will lead to plenty of problems, such as high rotor losses and low power factor, affecting the machine performance [4,5]. This paper presents a novel modular CP-PMSM equipped with two slot-pitches overlapping windings, which has the advantages of low rotor losses, modularization, and high-power factor. The proposed machine topology is shown in Fig. 1(a). For the stator, the stator shifting technique is employed to offset the non-working harmonics of armature reaction MMF, as shown in Fig. 1(b). For the rotor, the appropriate flux barriers are designed in the rotor yoke, as shown in Fig. 1(c), thereby reducing the flux densities of low order non-working harmonics. In addition, the machine has six stator teeth not covered by the winding ends, so that the stator can be modularized by cutting these teeth. The armature reaction magnetic field distributions of the conventional CP-PMSM with FSCW and the proposed machine are shown in Fig. 2(a). It can be seen that the periodicity of the armature reaction fields of the latter is more apparent. This is attributed to the lower non-working content of armature reaction flux density in the proposed machine, as shown in Fig. 2(b). Moreover, the torque ripple of the proposed machine is 43.51% lower than that of conventional one, as shown in Fig. 2(c). The PM eddy losses, rotor core losses, and stator core losses of the proposed machine are reduced by 73.28W, 17.55W and 25.89W respectively compared with the conventional machine, as shown in Fig. 2(d). According to the angle between the fundamental harmonics of the induced voltage and the input current, as shown in Fig. 2(e), the power factor of proposed machine can be calculated to be 0.89, which is 34.85% higher than that 0.66 of conventional one.References: [1] K. Wang, H. Lin, and H. Yang, "A novel modular 18-slot 10-pole pmsm with 9-phase unequal-coil-pitch fractional-slot winding," in 2018 21st International Conference on Electrical Machines and Systems (ICEMS), 2018, pp. 132-136. [2] Z. Q. Zhu, Z. Azar, and G. Ombach, "Influence of additional air gaps between stator segments on cogging torque of permanent-magnet machines having modular stators," in IEEE Transactions on Magnetics, vol. 48, no. 6, pp. 2049-2055, 2012. [3] S. Cai, Z. Q. Zhu, and C. Wang, et al., "A novel fractional slot non-overlapping winding hybrid excited machine with consequent-pole PM rotor," in IEEE Transactions on Energy Conversion, vol. 35, no. 3, pp. 1628-1637, 2020. [4] Y. Li, H. Yang, and H. Lin, et al., "Investigation of double-side field modulation mechanism in consequent-pole pm machines with concentrated windings," in IEEE Transactions on Energy Conversion, vol. 36, no. 3, pp. 1635-1648, 2021. [5] H. Yang, Y. Li, and H. Lin, et al., "Principle investigation and performance comparison of consequent-pole switched flux pm machines," in IEEE Transactions on Transportation Electrification, vol. 7, no. 2, pp. 766-778, 2021.
Large-scale permanent magnet synchronous machines (PMSMs) with high performance and low cost are urgently required in ship propulsion, power generation and other fields. Consequent-pole PMSMs (CP-PMSMs) with fractional slot concentrated winding (FSCW) have drawn increasingly more attention [1-3]. However, rich non-working harmonics in their armature reaction magnetic field will lead to plenty of problems, such as high rotor losses and low power factor, affecting the machine performance [4,5]. This paper presents a novel modular CP-PMSM equipped with two slot-pitches overlapping windings, which has the advantages of low rotor losses, modularization, and high-power factor. The proposed machine topology is shown in Fig. 1(a). For the stator, the stator shifting technique is employed to offset the non-working harmonics of armature reaction MMF, as shown in Fig. 1(b). For the rotor, the appropriate flux barriers are designed in the rotor yoke, as shown in Fig. 1(c), thereby reducing the flux densities of low order non-working harmonics. In addition, the machine has six stator teeth not covered by the winding ends, so that the stator can be modularized by cutting these teeth. The armature reaction magnetic field distributions of the conventional CP-PMSM with FSCW and the proposed machine are shown in Fig. 2(a). It can be seen that the periodicity of the armature reaction fields of the latter is more apparent. This is attributed to the lower non-working content of armature reaction flux density in the proposed machine, as shown in Fig. 2(b). Moreover, the torque ripple of the proposed machine is 43.51% lower than that of conventional one, as shown in Fig. 2(c). The PM eddy losses, rotor core losses, and stator core losses of the proposed machine are reduced by 73.28W, 17.55W and 25.89W respectively compared with the conventional machine, as shown in Fig. 2(d). According to the angle between the fundamental harmonics of the induced voltage and the input current, as shown in Fig. 2(e), the power factor of proposed machine can be calculated to be 0.89, which is 34.85% higher than that 0.66 of conventional one.References: [1] K. Wang, H. Lin, and H. Yang, "A novel modular 18-slot 10-pole pmsm with 9-phase unequal-coil-pitch fractional-slot winding," in 2018 21st International Conference on Electrical Machines and Systems (ICEMS), 2018, pp. 132-136. [2] Z. Q. Zhu, Z. Azar, and G. Ombach, "Influence of additional air gaps between stator segments on cogging torque of permanent-magnet machines having modular stators," in IEEE Transactions on Magnetics, vol. 48, no. 6, pp. 2049-2055, 2012. [3] S. Cai, Z. Q. Zhu, and C. Wang, et al., "A novel fractional slot non-overlapping winding hybrid excited machine with consequent-pole PM rotor," in IEEE Transactions on Energy Conversion, vol. 35, no. 3, pp. 1628-1637, 2020. [4] Y. Li, H. Yang, and H. Lin, et al., "Investigation of double-side field modulation mechanism in consequent-pole pm machines with concentrated windings," in IEEE Transactions on Energy Conversion, vol. 36, no. 3, pp. 1635-1648, 2021. [5] H. Yang, Y. Li, and H. Lin, et al., "Principle investigation and performance comparison of consequent-pole switched flux pm machines," in IEEE Transactions on Transportation Electrification, vol. 7, no. 2, pp. 766-778, 2021.