Design guidelines of bearingless PMSM with two separate poly-phase windings

This document provides design guidelines for bearingless permanent magnet synchronous motors (PMSM), which generate torque and lateral suspension forces via two separate poly-phase windings. The step-by-step bearingless motor development process is accompanied by explicit analytical formulas used in the dimensioning of the magnetic circuit and in the calculation of magnetic field quantities like flux densities in the air gap, electromagnetic torque and levitation forces. The design procedure is exemplified on a prototype with a rated mechanical power of 40 kW, reached at 40 000 rpm and having a hybrid five-axis levitation system composed of a bearingless unit and a combined axial-radial magnetic bearing.