Vibration control of rotor shaft systems using electromagnetic actuator

Abstract

Applicability of electro-magnetic actuator for active vibration control of long rotors, commonly found in power-plant turbines is addressed in this work through simulations. Appreciable vibration reduction with the Proportional- Derivative (PD) control law applied on the difference between nominal and instantaneous air-gap between rotor surface and actuator poles is reported in literature. This paper investigates and finds that the Proportional and high frequency band limited Derivative control action (abbreviated as PD hfbl) is much more efficient than the former in terms of unbalanced response reduction and increment of Stability Limit Speeds (SLS) of long rotor-shaft systems. This paper also establishes a philosophical link between the PD hfbl control action and a multi-element mechanical suspension model, or viscoelastic suspension model, reported to reduce response and increase stability limit speed of rotors in literature. Examples of simulations are presented in support of the conclusions.