Improved V‐shaped interior permanent magnet rotor topology with inward‐extended bridges for reduced torque ripple. Issue 12 (17th September 2020)

• Record Type: Journal Article
• Authors: Gao, Peng; Sun, Xibin; Gerada, David; Gerada, Chris; Wang, Xiaoyuan
• Is Part Of: IET electric power applications. Volume 14:Issue 12(2020)
• Page Start: 2404
• Page End: 2411
• Publication Date: 2020-09-17
• Subjects: air gaps -- synchronous machines -- rotors -- traction motors -- torque -- permanent magnet motors -- electric vehicles; radial force -- V‐shaped interior permanent magnet rotor topology -- sinusoidal air‐gap flux density waveform -- nonsinusoidal air‐gap flux density distribution -- electric vehicles -- traction motors -- interior permanent magnet synchronous machines -- reduced torque ripple -- inward‐extended bridges; Electric power -- Periodicals; Electric power systems -- Periodicals; 621.305
• DOI: 10.1049/iet-epa.2019.0850
• Languages: English
• ISSNs: 1751-8660

Abstract

Abstract : Interior permanent magnet synchronous machines (IPMSMs) with V‐shaped permanent magnet (PM) rotors are widely used as traction motors in electric vehicles because of their high torque density and high efficiency. However, the V‐shape IPMSMs have the disadvantages of inevitable torque ripple due to the non‐sinusoidal air‐gap flux density distribution and the utilisation of the reluctance torque. In this study, with the aim of improving the torque ripple characteristics, a modified V‐shaped IPMSM rotor configuration with bridges extended inwards towards the pole centre is proposed to generate a more sinusoidal air‐gap flux density waveform. The proposed topology, referred to as 'Type C' within this study, is compared with baseline rotor configuration references, namely 'Type A' which is a conventional V‐shaped PM rotor, as well as 'Type B' which is a related configuration with a mechanically non‐uniform air gap. The analysis results show that the rotor 'Type C' exhibits significant advantages in terms of reducing cogging torque, torque ripple and radial force, without incurring additional air‐gap friction losses. Finally, a prototype of the IPMSM with the proposed rotor configuration is manufactured and tested, verifying the predicted benefits experimentally.