Basic characteristics of a 4kW permanent-magnet type bearingless slice motor for centrifugal pump system

A new highly integrated 2times3 phase power electronics with digital controller is designed and implemented based on an existing 4 kW permanent-magnet type bearingless slice motor (BSM) with centrifugal pump developed by Levitronix GmbH Zurich. Firstly, general schematic and functional principle of bearingless slice motor pump system are briefly introduced. Secondly, analytical aspects of the bearingless slice motor concerning the arrangement of stator windings, generation of radial force and control strategy are demonstrated. Basic characteristics of the bearingless pump system are derived through experimental tests. Radial position deviation of rotor is within 300 mum when its rotational speed varies from 0 to 5400 rpm under water load. Experimental results show the validity of the performed controller and the investigated BSM system.