Research and analysis of different grades silicon steels for an ultra-high-speed PM motor

Ultra-high-speed permanent magnet motors (UHSPMMs) operate at extremely high rotational speeds, which results in a very high operating frequency in the stator core. This causes significant losses of the core, in particular eddy current losses. Consequently, the reduction in the thickness of the silicon steel laminates has become a widely accepted method to minimize high frequency core losses. To study the influence of silicon steel sheets of various specifications on the electromagnetic properties of UHSPMMs, this paper examines four silicon steel sheets of varying thicknesses and their use in motors. First, the magnetic properties of four silicon steel sheets of four thicknesses, namely, 0.1, 0.15, 0.2 and 0.25 mm, were compared and analyzed, and their composition was separated from the core loss. When applied to a 25 kW, 95 kr/min ultra high-speed motor, the effects of the characteristics of the different grades of silicon steels on motor performance such as torque, core losses, and efficiency were analyzed. Finally, the motor was fabricated on 0.15 mm silicon steel, and the accuracy of the motor theoretical calculations was verified by testing. This document provides the basis for the selection of the basic materials for UHSPMMs, which have both scientific and technical value.