Performance Analysis of a Line-start Flux-modulated Machine

The line-start permanent magnet synchronous machine (LSPMSM) is considered a promising alternative to conventional induction machines due to its high torque density, compact size, high efficiency, and enhanced power factor. However, the cage winding on the rotor, which is only active during startup, inevitably occupies space that could otherwise be utilized for magnetic flux paths within the rotor structure. To address this issue, a novel line-start flux-modulated machine without a conventional squirrel cage winding is proposed and analyzed. This machine, specifically termed the permanent magnet synchronous machine with axial magnetization rotor (AMR-PMSM), features a simple and robust rotor structure. In this paper, a systematic comparative analysis is conducted on stator/rotor pole combinations of the AMR-PMSM, with a focus on investigating the impact of different pole numbers on the machine’s steady and starting characteristics. Finally, a 12s/50p AMR- PMSM prototype machine is manufactured and tested to demonstrate the analysis method.