Rotor Strength Analysis of Ultra-High Speed Permanent Magnet synchronous Motor

Abstract

When permanent magnet synchronous motor is running at ultra-high speed, the tensile strength of permanent magnet is far lower than the compressive strength, and it is unbearable to withstand the large centrifugal tension caused by rotation. Generally, adding the non-magnetic alloy sleeve outside the permanent magnet is the protective measure. In this paper, the influences of static interference, the thickness of sleeve and sleeve material on rotor strength are analyzed, and the strength design rules of ultra-high speed permanent magnet synchronous rotor are summarized. Taking a permanent magnet synchronous motor with rated power of 1kW and rated speed of 500000r/min as an example, the strength design method is given and the rotor stress under three working conditions is checked by finite element method, which is static, rated speed and rotation at high temperature respectively, verifying the correctness of the design.