Active Control of Bridge Configured Self-bearing Motor, a Numerical Study

Vibration is a major concern of the rotating machine industry. The wear and tear of the support bearing and the eccentric motion of the rotor are among the main sources of vibration of an electrical machine. The development of a bearingless machine is a good way to address this problem. This paper mainly focuses on the development of a bearingless bridge configured winding (BBCW) induction motor. The bridge configured winding (BCW) is a specialized single set of winding scheme, which has the capability to produce the torque and the transverse force simultaneously. There are two sets of supply for this winding scheme. The three-phase main supply produces a p-pole pair of the magnetic field and is responsible for the torque-producing component. The external supply in the bridges produces a p ± 1 pole pair of the magnetic field. The interaction between these two fields produces a net radial force, which is used to neutralize the various forces acting on the rotor and the weight of the rotor. The magnitude and the direction of this magnetic force can be controlled by supplying currents or voltages at different frequencies and amplitudes through the bridge points of the BCW winding. There is no study in the literature related to the development of bearingless machine using BCW scheme. In the present work, a Simulink model of a BBCW induction motor has been developed. The convergent control scheme has been used for the control of forces of various frequencies acting on the rotor. The PID controller has been used for the levitation of the rotor. The shaft of the motor has been modeled as a Euler–Bernoulli beam, and it is supported by only one isotropic bearing at the one end. The other end of the rotor has been kept unsupported to demonstrate the levitation effect.