Interior Permanent Magnet Motors for Traction Application with Non-Overlapping Concentrated Windings and with Integer Slot Windings

In this paper, interior permanent magnet machines using either integer slot windings or non-overlapping concentrated windings are designed and analyzed for traction applications. Nowadays, Permanent Magnet (PM) synchronous reluctance motors are often used in traction applications because of their ability to control the stator flux in the field weakening operation. Reluctance torque is produced due to the inductance difference between the direct and quadrature axes' inductances and the stator current linkage. Power density can be increased by adding interior permanent magnets to the machine. The authors were interested in studying whether the reluctance torque can also be beneficial when using non-overlapping concentrated windings. Two 25 kW motors were designed in the same frame. Both motors should give at least 2 p.u. torques at low speed and approximately 0.6 p.u. at double speed as the rated speed is fixed to 1000 rpm. Analytical computations are verified by finite element analysis utilizing Cedrat's Flux2D. It was noticed that a non-overlapping concentrated winding machine can also be used as traction motor and can further be designed to produce reluctance torque. The integer slot motor has been built and measured and thereby the theoretical computations are verified by real measurements. Copyright (C) 2011 Praise Worthy Prize S.r.l. - All rights reserved.