The old principle of storing energy as kinetic energy in a rotating flywheel has seen renewed interest due to a large energy-storing potential caused by recent advances in motor, magnetic bearing, and fiber-composite technology. Magnetically suspended flywheel energy storage systems (FESSs) are now used in commercial applications. However none of these applications are mobile. Due to the outer perturbations which complicates the design, FESSs in vehicles have only seen successful experimental operation in a few research projects whereas theoretical models of these systems are still missing.
The potential of the technology is high due to safety and environmental advantages over electrochemical batteries. With the prospect of utilizing nanofiber composites, the storage capacity can potentially exceed that of electrochemical batteries. Due to the outer perturbations, however, more practical experience and better mathematical models are needed to further advance the design of mobile FESSs.
In this work, multi-body modelling and rotordynamics combined with magnetic bearing theory are used to develop a mathematical model of a gimbal mounted FESS subject to outer perturbations. The gimbal mount is incorporated to reduce gyroscopic loads. An experimental test rig is built to test the moving FESS in practice and to validate the mathematical model.
The mathematical model is agreeing with experimental results. The test rig is used to demonstrate stable levitation of a rotor when spinning high speed and subject to perturbations from a moving foundation. The gimbal mount is effectively removing gyroscopic loads but causing the flywheel housing to move unintentionally. Using the mathematical model, the moving FESS can be designed to best handle and/or minimise forces and unintended motions of the system.
Supervisor:
Professor Ilmar Santos, DTU Mechanical Engineering
Examiners:
Professor Peder Klit, DTU Mechanical Engineering
Professor Daniel J. Rixen, Technical University of Munich, Germany
Professor Patrick Keogh, University of Bath, United Kingdom
Chairman:
Associate Professor Jan B. Høgsberg, DTU Mechanical Engineering