Experimental Characterization and Finite Element Correlation of Rotor Stress\Strain for a High-Speed Permanent Magnet Synchronous Machine

A higher machine speed is an enabling factor in achieving a higher power density. However, higher speed poses a challenge to the structural integrity of the rotor, as the centrifugal force acting on the rotor increases quadratically with speed. This high stress may lead to failure in the rotor ribs and bridges of an Interior Permanent Magnet Synchronous Machine (IPMSM). This paper presents a high-speed rotor strain measurement experimental setup that uses strain gauges and a telemetry system to measure strain at critical locations of the IPMSM rotor up to 18,000 rpm. Strain measurements are conducted at both room and high temperature to emulate the operating conditions of a high-speed machine. The measured strain is then correlated with the results of the finite element analysis strain to evaluate the fidelity of the rotor stress model. Also, the effect of anisotropic mechanical properties of electric steel on rotor strain is investigated.