Analytical modelling of a consequent-pole bearingless permanent magnet motor

The paper describes an analytical modelling technique for calculating the radial force on the rotor of a bearingless consequent-pole permanent magnet motor. The advantages of the technique is the flexibility with which it is applied so that it is used to identify vibration components and also calculate the force in a variety of situations when the rotor is not centred in the bore, i.e., when the rotor has either dynamic eccentricity, static eccentricity or when the rotor is vibrating in the stator bore. It also allows the force to be calculated with a varying load or even with load imbalance. The paper studies the effects of winding design and gives a qualitative comparison to the force calculated using 2D finite element analysis under different loads.