Development of a stabilizer for oscillating torques in synchronous machines

Abstract — A novel torque stabilizer was developed and has been continously applied at IPP as a countermeasure to torsional vi-bration and resonance problems in synchronous machines. Such problems are most frequently encountered in rotor systems with long shafts and large inertias constituting a weakly damped me-chanical resonator which exhibits a low resonance frequency, e. g. 10 – 30 Hz. The paper presents examples for the successful suppression of torsional resonances in synchronous machines of the IPP experimental power supply, an isolated power system based on flywheel generators. The novel torque stabilizer is a powerelectronic device which is connected to the stator winding of the synchronous machine. It produces the same effect as an increased natural damping for oscillation modes in the rotating shaft assembly. It is therefore universally applicable to torsional vibration problems in generators and electrical drive systems. Index Terms: Rotor dynamics, torsional vibration, subsynchronous resonance, power electronics, real-time control, numerical simula-tion I