Single Plane Balancing of Rotor-AMB System Using Virtual Trial Unbalances

The present work utilizes the influence coefficients and virtual trial unbalances as magnetic excitation to predict the residual unbalances in the rotating machinery. This approach reduces the effort involved in manual addition of the trial unbalances.

The virtual trial unbalances (VTUs) are generated at the active magnetic bearing (AMB) position by adding excitation current to the control current. The forces generated by additional excitation current imitates the manually added trial unbalance without interfering to the stability of the rotor system. The experiments are carried out on the RK-4 rotor test rig supported on two journal bearings and integrated with AMB. The PID controller implemented in the AMB is designed the SIMULINK platform with data acquisition system (DAQ). The half-spectrum amplitudes and phases of the displacement responses are utilized with and without the addition of VTUs to estimate the residual unbalances.

The rotor system is balanced as per the estimation results obtained using VTUs, and the displacement response of the system is found out to be reduced. This confirms the effectiveness of the algorithm in balancing of rotor-AMB systems.