Dynamic analysis and vibration control of a rotor system using rotating permanent magnets

Abstract

The rotor system, as the core component of rotating machinery, is widely used in power transmission and conversion devices in fields such as energy power, and aerospace. As rotor systems evolve towards high operational speeds, their dynamic stability problems become increasingly critical, emerging as a key factor limiting equipment performance and reliability. Active Magnetic Bearings (AMBs) exhibit significant potential in the field of active vibration control for rotor systems due to their online tunable stiffness and damping characteristics, coupled with inherent advantages such as being non-contact, wear-free, and requiring no lubrication. However, the primary obstacle currently preventing AMB technology from transitioning from laboratory research to large-scale engineering applications is its high manufacturing and maintenance costs. Consequently, exploring low-cost, high-performance AMB solutions has become a key research focus in this field.
Traditional research often employs AMBs merely as independent supporting components, which imposes limitations on their control functionality and application effectiveness. To break through this bottleneck and achieve highly efficient vibration suppression in rotor systems, this research is dedicated to developing a novel non-contact actuation method based on the principle of active magnetic flux path control. The core of this method lies in generating the required oscillating electromagnetic force by controlling the magnetic flux path, thereby directly applying non-contact actuation to the bearing-rotor system, aiming to enhance the practicality and economic feasibility of vibration control. Based on this approach, this study will independently establish an integrated actuator-bearing-flexible rotor test rig incorporating a variable magnetic flux path control system. The effectiveness of the proposed control method will be systematically validated under various operating conditions, including steady-state operation at different speeds and transient acceleration processes.
Furthermore, the gyroscopic effect induced by intentionally offset rotor discs introduces additional complexity to the system's dynamics, particularly during transient maneuvers. This effect, coupled with the inherent flexibility of the rotor, leads to coupled lateral and torsional vibrational modes that are highly speed-dependent and challenging to suppress with conventional control architectures. The proposed magnetic flux path control mechanism is specifically designed to target these complex vibrational phenomena. By leveraging real-time feedback of the rotor's state, the control system dynamically adjusts the magnetic field to apply counter-acting forces, effectively damping the vibrations before they can amplify.
The experimental validation phase will comprehensively assess the performance metrics, including vibration attenuation efficiency and stability margins. Successful implementation of this research is anticipated to establish a new paradigm for cost-effective and high-performance vibration management in high-speed rotating machinery, with direct implications for enhancing the design and operational envelope of next-generation turbomachinery, flywheel energy storage systems, and advanced propulsion systems.

Date of Award	15 Nov 2026
Original language	English
Awarding Institution	University of Nottingham
Supervisor	Dunant Halim (Supervisor), John Xu (Supervisor) & Liang Huang (Supervisor)