Unbalance Response of a Magnetically Suspended Dual-rotor System

The magnetic suspended dual-rotor system (MSDS) applied in more electric aero-engine can eliminate the wear and lubrication system of mechanical bearings and solve the vibration control issue of system effectively, which provides the possibility to improve the performance of aero-engine significantly. This research focuses on the unbalance response of the MSDS. First, a structure of dual-rotor system supported by two active magnetic bearings (AMBs) and two permanent magnetic bearings (PMBs) is proposed. With classic PD control adopted, the bearing characteristics of AMBs are modeled as the equivalent stiffness and equivalent damping, and the PMBs are modeled as elastic support with stiffness. Then, the Riccati transfer matrix method with good numerical stability is used to establish the unbalance response model of the MSDS. Next, the interaction between inner and outer rotors is analyzed with single rotor imbalance excitation, and the unbalance response of the MSDS is investigated with dual-rotor imbalance excitation. In addition, a simple and effective approach to avoid simultaneous excitations by both inner and outer rotors is pointed out. Finally, experiments on the unbalance response of a magnetic suspended single-rotor system is conducted to validate some theoretical analysis of the MSDS.