Suppression of imbalance vibration for AMBs controlled driveline system using double-loop structure

Because of the couplings without off-line balancing and the uneven distribution of the rope, the equivalent residual unbalances in the active magnetic bearing (AMB) controlled driveline system are considerable. Therefore it is necessary to achieve suppressing the synchronous vibration force over the entire operating speed range. To completely achieve automatic balance of the rotor, a double-loop compensation design approach based on the AMB is proposed. Firstly, a dynamic model of the rotor with imbalance and the decentralized control system of magnetic bearing are established. Then the imbalance characteristic of the rotor system is identified by the generalized notch in which sign of the convergence coefficient needs to be changed according to the rotational speed. Finally, the second loop which is a simply feedforward loop at low speeds and switched to an adaptively tuning loop at high speeds is used to adjust the control current to achieve complete suppression of the imbalance vibration force. The method can achieve automatic balancing within the entire operating speed range and the effectiveness is unaffected by the attenuation of power amplifier at high speeds. Simulation and experiment results well demonstrate effectiveness of the approach, and the stability of the whole system is guaranteed. (C) 2014 Elsevier Ltd. All rights reserved.