Experiment and Numerical Analysis of a Magnetizing Technique for Permanent Magnets of IPM Motors using HTS Bulk Magnets

Abstract

Intense magnetic fields exceeding 2 T are necessary to magnetize rare-earth magnets to extract the full performance of magnet materials. In this report, we deal with the experimental measurements and numerical analysis of the magnetic flux after scans of the 3 T HTS bulk magnet on the surface of the rare-earth magnet. The distributions of the magnetic flux density between measured and simulated data on the magnet slab showed good agreement after the scanning. The study is conducted to evaluate the magnetization performances of bulk magnets for the interior permanent magnet (IPM) motors. According to the numerical analysis, the magnetic field of 3 T reached the point of 22 mm from the surface of the rotor. The experimental data clarified that the magnet slab (26 × 20 × 5 mm³) in the rotor was fully magnetized by scanning the bulk magnet on it, while the neighboring magnet was barely magnetized in the rotor because of its anisotropic magnetizing property. This shows that the magnets in IPM motors are capable of being activated from outside the rotors with use of HTS bulk magnets, which suggests an improved degree of freedom in designing the motor.