Development and test of high-speed bearingless PM synchronous machines

Abstract

Two high-speed bearingless permanent magnet (PM) synchronous motor prototypes with different mechanical and electrical ratings are presented from the design and performance point of view. For high speed application magnetic bearings are necessary, which in the bearingless design are integrated into the active motor part. The first prototype BM-1 was designed for a rotational speed of 60,000 rpm and a mechanical power of 500 W, e.g. as a drive for turbo vacuum pumps. The second prototype BM-2 has an increased mechanical output power of 40 kW at a rated speed of 40,000 rpm, being a suitable drive for compressors and high-speed tooling machines. Entwicklung und Erprobung von lagerlosen Hochdrehzahl-PM-Synchronmaschinen.Zwei lagerlose Hochdrehzahl-Permanentmagnet(PM)-Synchronmotorprototypen mit unterschiedlichen mechanischen und elektrischen Bemessungsdaten werden hinsichtlich Auslegung und Betriebsverhalten dargestellt. Bei "lagerlosen Maschinen ist die f€ ur hohe Drehzahlen erforderliche magnetische Lagerung in den Aktivteil der elektrischen Maschine integriert. Der erste Prototyp BM-1 wurde f€ ur eine Drehzahl von 60.000 min -1 und eine mechanische Leistung von 500 W ausgelegt, z. B. als Antrieb f€ ur Turbovakuumpumpen. Der zweite Prototyp BM-2 hat eine erh€ ohte mechanische Leistung von 40 kW bei einer Bemessungsdrehzahl von 40.000 min -1 , was ihn f€ ur Kompressoren und Spindelantriebe geeignet macht.Schlü sselwö rter: elektrische Hochdrehzahlmaschinen; PM lagerloser Motor; magnetische Lagerung; Radialmagnetlager

Optimum Pole Number Combination of a Buried Permanent Magnet Bearingless Motor and Test Results at an Output of 60 kW With a Speed of 37000 r/min

“…Based on the rotor diameter and axial lengths of 58 mm and 46 mm, respectively, and one-unit power and torque of 30.3 kW and 7.82 Nm, respectively, the power and torque densities were 248 kW/L and 64 Nm/L, respectively. These values were 3.6 and 3.9 times as high as the one previously described [15]. If these densities were defined based on the stator core outer cylindrical volume, they would have been 42.8 kW/L and 11 Nm/L, respectively.…”

“…A bearingless motor with 30000 r/min was also designed [14], but the output power was only 5 kW. A surface permanent magnet (SPM) synchronous bearingless motor was built, and the test results reported an output of 40 kW and a rotational speed of 40,000 r/min [15]- [19]; the basic characteristics were presented. However, eddy current loss in the SPM structure reduced the efficiency.…”

Bearingless PM synchronous machine with zero-sequence current driven star point-connected active magnetic thrust bearing

“…Often the thrust bearing is realized parallel to a radial AMB as combined AMB [5] on the non-drive end (NDE) of the shaft, whereas the BM is mounted on the drive end (DE) in order to achieve a short axial length. But even if two BMs as two half-motors are used [18], an additional axial AMB is required. In any case, this axial AMB is usually fed by a DC chopper, which is costly.…”