Vibration Control of a Horizontally Supported Rotor System by Using a Radial Active Magnetic Bearing

Abstract

This paper deals with the control of vibration of a rotor system using a four-pole Radial Active Magnetic Bearing (RAMB). A continuous rotor system model is considered for the analysis. Several important factors, like the gyroscopic effect and rotary inertia of the disc and the shaft, are incorporated in this model. The large deflection of the shaft and the restriction to axial motion of the shaft at the bearings result in nonlinearities in the system governing equations. The governing equations are derived using Hamilton’s principle and the method of modal projection. Active controlling of the system vibration is achieved by integrating a Proportional-Derivative (PD) controller into the system through the magnetic force generated from a four-pole RAMB. Numerical and analytical studies are performed. Analytical expressions for the amplitude and phase equations are derived using the Method of Multiple Scales (MMS). Analytical results are verified with the numerical results obtained using a ‘ode’ solver in-built in MATLAB software. The results obtained prove the effectiveness of using the PD controlled RAMB for the attenuation of rotor system vibrations.

Keywords: Active magnetic bearing, continuous rotor system model, method of multiple scales, PD controller, rotor dynamics