Effects of Flux Intensifying and Variable Leakage Flux on Spoke-Type IPM Motor Performance and Demagnetization

This paper investigates the effects of Flux Intensifying (FI) and Variable Leakage Flux (VLF) on the performance and demagnetization risk of FI-SIPM and VLF-FI-SIPM motors in comparison to a conventional spoke-type interior permanent magnet (SIPM) motor under wide-speed-range operation. First, an equivalent magnetic circuit model is developed to highlight the rotor design differences among the three motor types. The study then further examines how FI and VLF influence the magnetic flux density distribution in the permanent magnet (PM) and their effectiveness in mitigating PM demagnetization. This evaluation is conducted at three critical operating points: base speed, mid-speed range, and maximum speed. Additionally, the performance assessment evaluates key metrics, including iron loss, efficiency, and power factor (PF), across these operating points, providing a comprehensive comparison of the three types of SIPM motor designs for wide-speed-range applications. The analysis results are validated through Finite Element Analysis (FEA).