OF DOCTORAL DISSERTATION HELSINKI UNIVERSITY OF TECHNOLOGY P.O. BOX 1000, FI-02015 TKK http://www.tkk.fi Author Andrej Burakov Name of the dissertation Modelling the unbalanced magnetic pull in eccentric-rotor electrical machines with parallel windings Manuscript submitted 08.06.2007 Manuscript revised 07.10.2007 Date of the defence 25.10.2007 Monograph Article dissertation (summary + original ...

The purpose of this paper is the calculation of Unbalanced Magnetic Force (UMF) in permanent magnet brushless DC (PMBLDC) machines with diametrically asymmetric winding and investigation of UMF variations in the presence of phase advance angle. This paper presents an analytical model of UMF in surface mounted PMBLDC machines that have a fractional ratio of slot number to pole number. This model...

Electromagnetic fields in the air gap of an electric machine produce electromagnetic forces between the rotor and stator. The total force exerted on the rotor due to the eccentric rotor position is called the unbalanced magnetic pull. This eccentricity force is directed roughly over the shortest air gap. At low frequencies, the vibration amplitudes of flexural modes may be large enough to coupl...

The vibration and noise of permanent magnet synchronous motors (PMSM) are mainly caused by unbalanced magnetic pull (UMP). This paper aims to investigate nonlinear vibration in PMSMs. Firstly, the analytical model of the air-gap magnetic field with an eccentric rotor in PMSM is studied, and the analytical model is verified by the finite element method. Then the dynamic model of an offset rotor-...

This paper presents a proposition of sliding mode position controller of the magnetic suspension ball system . The magnetic suspension system (MSS) is a mechatronic system already acknowledged and accepted by the field experts. The design of a controller keeping a steel ball suspended in the air. In the ideal situation, the magnetic force produced by current from an electromagnet will counterac...

This paper deals with the control aspects of magnetic levitation system using fuzzy logic controller (FLC). The magnetic levitation system is a mechatronic system already acknowledged and accepted by the field experts. For such a system it is desired to proposed a suitable controller for positioning a metal sphere in air space by the help of an electromagnetic force. In the ideal situation, the...

This paper describes the effects of induced magnetic field and partial slip on the peristaltic flow of a couple stress fluids in an asymmetric channel. The two dimensional equation of couple stress fluid are simplified by making the assumptions of long wave length and low Reynolds number. The exact solutions of reduced momentum equation and magnetic force function have been computed in wave...

Unbalance in magnetically levitated rotor (MLR) can cause undesirable synchronous vibrations and lead to the saturation of the magnetic actuator. Dynamic balancing is an important way to solve these problems. However, the traditional balancing methods, using rotor displacement to estimate a rotor’s unbalance, requiring several trial-runs, are neither precise nor efficient. This paper presents a...