Multivariable H? or Centre of gravity PD control for an active magnetic bearing flywheel system

Abstract

A state-space model with uncertainties for an active magnetic bearing energy storage flywheel system (Fly-UPS) is developed. A multivariable robust H? controller for the Fly-UPS is then synthesised. Different weighting schemes are explained and the additive uncertainties between the nominal simulation model and the physical model at varied rotational speeds are characterised. Furthermore, PD controllers are developed using the centre of gravity (COG) coordinate framework for decoupled parallel and conical modal control. Stability robustness is verified via the gain/phase margin stability robustness criterion. The performance robustness (disturbance attenuation) is analysed by assessing model sensitivity with the ISO/CD 14839-3 sensitivity standard. The results obtained show that H? control and COG coordinate PD control are not fundamentally different.