Design of Permanent Magnet Synchronous Motor for Low Speed Applications with Fractional Slot Concentrated Windings

Abstract

This thesis covers the design of permanent magnet synchronous motor (PMSM) with fractional slot concentrated windings (FSCW). PMSMs with FSCW are most suit- able for low speed direct drive applications. PMSMs with FSCWs o er advantages like; high pole number with less number of slots and shorter end turn length of the windings, which ultimately decreases the amount of copper to be used. The speci cations of PMSM are 45 kW, 400 rpm, and 1000 Nm, speci cally used for pulp and paper industry applications. Analytic design of PMSMs with di erent slot/pole combinations is carried out with motor design software. The main concern was to nd a machine design that resulted in a low amount of airgap ux density harmonics. In order to nd a suitable design, the machine performance was studied for di erent slot/pole combinations. Thus a low airgap ux density harmonic in the machine with 48/40 slot/pole combination is obtained. Special attention is given to the airgap ux density harmonics of the machine. This selected design is studied with nite element method (FEM) in order to verify the analytical results. A comparison is made between analytical design and FEM simulation, the result shows acceptable correlation, leading to the ful llments of the requirements. Further optimization of the design to reduce airgap ux density harmonics is car- ried out with the FEM simulations. The design is optimized thorough shaping of permanent magnet and varying the stator slot opening width methods.