Pratt-whitney Canada Corp

Peter Ficklscherer

Reza Pedrami

A speed control system for an engine comprising at least one rotary load is provided. The speed control system may include a rotor speed controller configured to regulate speed in the rotary load based on a sensed rotor speed, exclusive of resonant mode speed oscillations, in closed loop feedback with a commanded rotor speed. To provide active damping of resonant mode speed oscillations, a resonance disturbance rejection controller may be configured to compensate a speed control signal by observing a component of the sensed rotor speed that is due to resonant mode oscillations. Based on the observed resonance component, the resonance disturbance rejection controller may compute an adjustment value for the speed control signal. In the particular case of gas turbine engines, the resonance disturbance rejection controller may effect active damping by compensation of a fuel flow request for a gas generator.

Rotor resonance disturbance rejection controller

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.

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Schoefweg, Germany

Peter Ficklscherer