Resonant mode damping system and method

摘要

A control system for increasing the damping of a resonant mode of a rotor drive train is provided. A control loop is introduced in parallel with the free turbine speed governing control loop. The control loop receives a feedback signal from the free turbine and rotor drive train, the feedback signal representative of the free turbine speed. The control loop extracts the resonant component from the feedback signal to generate a resonant signal containing the resonant component and estimates a derivative of the free turbine speed from the resonant signal. The control loop then outputs a request for damping the resonant mode on the basis of the derivative. A narrow-band reject filter is introduced in the free turbine speed governing loop to filter out the resonant component from the feedback signal, thereby ensuring that the free turbine speed governing loop does not interfere with the control loop.

主权项

1. A system for damping at least one resonant mode of a rotor drive train of an engine having a generator comprising a free turbine, the at least one resonant mode occurring at at least one resonant frequency, the system comprising:
a filtering unit adapted to receive a speed signal indicative of a present measurement of a speed of rotation of the free turbine and containing the at least one resonant frequency and a plurality of contributing frequencies, the filtering unit adapted to decouple the speed signal into a resonant signal and a resonant-free signal by attenuating the contributing frequencies to generate from the speed signal the resonant containing the at least one resonant frequency and the attenuated contributing frequencies, and attenuating the at least one resonant frequency to generate from the speed signal the resonant-free signal containing the plurality of contributing frequencies and the attenuated at least one resonant frequency; and a compensator unit coupled to the filtering unit and adapted to receive the resonant signal and estimate therefrom a derivative of the speed signal and to generate from the derivative a damping signal indicative of a request to adjust a speed of the generator for damping the at least one resonant mode.