Active position control of high speed drive systems

High speed drive systems are often described at an operating point above the critical speed. Therefore, the resonance frequencies have to be passed twice (start up / run down). In the worst case, the strong vibrations at critical speeds can lead to self-destruction. Unbalanced rotors are the main cause for the self-excited vibrations. Over the past years, the focus of investigations [1] was laid on the improvement of the operating characteristics by using passive elements to guarantee stability of the system. However, the transition through the critical speed is still an unwanted high mechanical strain. In this paper, an innovative concept for rotary drives will be presented, which is able to compensate excessive vibrations or deflections actively. A permanent magnet excited synchronous motor (PMSM), which is able to generate motor torque and radial force simultaneously [2], with a large air gap is used. The capability of generating a highly dynamic and active control variable for the rotor position opens up new opportunities for drive applications. In this work, many different technical disciplines are combined, creating a truly mechatronic product.