Electromagnetic Characteristic Analysis of High-Speed Motors With Rare-Earth and Ferrite Permanent Magnets Considering Current Harmonics

In general, permanent magnet (PM) motors are driven by a pulsewidth modulation (PWM) voltage source inverter for vector control. The generated PWM signals cause high-frequency voltage components at the carrier frequency. Such components can increase the electromagnetic losses, thereby necessitating the consideration of the phase current corresponding to the carrier harmonics. This study aims to examine the feasibility of high-speed PM motors in which rare-earth magnets are replaced with ferrite magnets, by considering the current harmonics. The electromagnetic characteristics of a high-speed motor with rare-earth and ferrite PMs were analyzed considering the current harmonics. Based on the existing rare-earth magnet model, a ferrite magnet model with the same performance was developed to perform a comparative analysis. The findings were validated via comparison with the experimental results of the manufactured models.