F. Demmelmayr, A. Eilenberger, M. Schrödl:
"Sensorless Electric Traction Drive with 500 Nm Outer Rotor Permanent Magnet Synchronous Machine";
Talk: International Conference on Electrical Machines ICEM, Rom, Italy; 09-06-2010 - 09-08-2010; in: "Proceedings of International Conference on Electrical Machines", (2010), ISBN: 978-1-4244-4175-4; 1 - 7.

This paper presents calculations and measurements
for a permanent magnet synchronous machine (PMSM) with
buried magnets. Due to wide field weakening capability and high
utilisation of this external rotor machine, it can be especially used
for traction applications. The steady-state torque is about 346 Nm
and overload torque at three times nominal current is about 580
Nm. Fractional-slot concentrated windings instead of distributed
windings are used to increase the degree of automation. The
short-circuit-proof machine is non forced air-cooled.
The no-load torque ripple is calculated by numerical simulation
and compared with measurement results. Also the so-called
"Characteristic INFORM curves" for sensorless position control
capability are presented. The efficiency curve of the machine
provides high effiency of 94 % over a wide operation range.