A mechanical system with inertia and stiffness has natural resonant frequencies. The natural resonant modes in complex multi-inertia systems, (for example in the drive-train of an aircraft generator, ship propeller or wind turbine) can be excited by changes in the electrical system, and may result in excessive wear and reduction of lifespan of mechanical components. Conversely, variations in mechanical loading have the potential to cause electrical network instability. This research looks at how the electrical machine controller which couples the electrical and mechanical systems, can be used to suppress, rather than amplify the excitation of critical frequencies.
This project has developed analytical and modelling methods for the integrated electro-mechanical system, in order to identify resonant modes. A test platform of an aircraft generator driveline has been constructed with two representative dominant resonant modes. Step changes in the electrical load have been shown to excite oscillatory transients in the driveline torque, validating the simulation models.
Active work package:
The test platform is being used to demonstrate how generator tuning gains affect the magnitude and duration of the torque transients. Techniques for avoiding or suppressing the oscillations, through system design and intelligent control are being investigated.