A Novel Intersect Consequent Pole IPMSM Incorporating Rotor Gap and 3-D MEC for Magnet Reduction and Performance Improvement

초록

Electric machines account for roughly 35-40% of global electricity use, making efficiency improvements essential for reducing energy consumption and CO2 emissions. Rare-earth permanent magnets enable compact and high-performance designs but face issues of high cost and supply-chain vulnerability, motivating research on magnet-saving structures. One candidate is the consequent-pole topology, which significantly lowers magnet usage but inherently suffers from asymmetric magnetic fields that cause back-EMF distortion, torque pulsation, and demagnetization concerns. To address these drawbacks, this study introduces an intersect-type rotor configuration in which N and S poles are arranged symmetrically along the axial direction. While this configuration improves magnetic balance and suppresses torque ripple and cogging, it introduces axial leakage that reduces average torque and increases eddy-current losses. A dedicated rotor-gap design and a three-dimensional magnetic equivalent-circuit model are therefore developed to accurately capture axial flux paths with drastically lower computational burden compared to full 3-D finite-element analysis. Optimization of magnet geometry, demagnetization assessment, and loss evaluation are performed, followed by fabrication and testing of a V-shaped prototype. The proposed configuration achieves a 31.8% reduction in magnet material, a 51.3% decrease in cogging torque, and a 3.41%p reduction in torque ripple while maintaining the same output characteristics as a conventional design, demonstrating its potential as a high-efficiency and cost-effective alternative. At this time, the Ensys electromagnetic analysis program was used.

키워드