Evaluation of Posicast Compensator Robustness for the Reduction of Torsional Vibrations

The drivetrain of most aircraft engines, which links the electrical generators to the engine, is relatively flexible and has vibration modes with values below 100 Hz. Consequently, torsional vibrations can be excited by the sudden connection or disconnection of electrical loads, which is known as electromechanical interaction and can reduce the drivetrain lifespan. Past studies proposed the use of a Posicast compensator for reducing the excitation of torsional vibrations in aircraft drivetrains after electrical loads are connected. However, this method depends on the vibration modes of the mechanical system and hence it can be susceptible to parameter's uncertainty. In this paper, the robustness of the Posicast method is assessed analysing simulation and experimental results. In this paper, the main sources of uncertainty are identified, and a theoretical analysis is carried out to establish safe operation limits. Furthermore, to reduce the uncertainty to the inductances of the system strategies robust to them are introduced and analysed.