Introduction to COMSOL based Modeling of
Levitated Flywheel Rotor
Adam Piłat, [email protected]
Faculty of Electrical Engineering, Automatics, Computer Science and ElectronicsDepartment of Automatics
Ludwigsburg, October 26th, 2011
Agenda
• Active Magnetic Levitation• Kinetic energy storage system• Active Magnetic Suspension & Active Magnetic Bearing –
laboratory equipment• Flywheel optimization• Components integration• Eigenfrequency analysis• Other aspects and future work• Conclusions
Active Magnetic Levitation
• Non-contact operation• No mechanical friction• Dynamics control • On-line monitoring and
supervisory control
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Kinetic energy storage system
• Flywheel energy storage (FES) works by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy;
• System components: rotor, bearings, motor/generator, control system, energy transmission system
• Research towards optimal structure by analysis and study on materials, bearings, rotor dynamics, aerodynamical friction, safety, economical aspects
AGH - Active Magnetic Suspension & Active Magnetic Bearing – laboratory equipment
• Experience in Design, Prototyping, Modelling, Simulation, Identification and Control System
• AMS and AMB prototypes• Custom controller• Custom methods for
integrated prototyping including control tasks
Active Magnetic Bearing (AMB)
PAC - Hard real-time Controller
Active Magnetic Suspension(AMS)
Towards optimal flywheel
Towards flat disk and rigid bodyTypical constructions
Motor/generator
Bearing
Bearing
Radial stress[Pa]
Radius [m]
Optimization of Flywheel profile
• Aluminum
0.04 0.06 0.08 0.1 0.120
0.005
0.01
0.015
0.02
r [m]
h [m
]
300050001000015000
0.04 0.06 0.08 0.1 0.120
0.005
0.01
0.015
0.02
r [m]
h [m
]
300050001000015000
• Steel
Flywheel profiles for a different rotational speeds given in rpms. a) aluminum; b) steel.
Optimization of Flywheel profile
• Aluminum • Steel
0.04 0.06 0.08 0.1 0.120
1
2
3
4
5
6x 10
7
Radial coordinate [m]
Stre
ss σ
[Pa]
σ rσ φ
σ rσ φ
0.04 0.06 0.08 0.1 0.120
5
10
15
x 107
Radial coordinate [m]
Stre
ss [P
a]
σ rσ φ
σ rσ φ
Radial (blue) and azimuthal (red) stress components for initial (dashed line) and optimized (solid line) flywheel profiles calculated at 1500 rpm. a) aluminum; b) steel
Kinetic energy stored vs rotational speed
2000 4000 6000 8000 10000 12000 14000
2000
4000
6000
8000
10000
12000
ω [rpm]
E k [J
]
AluminumSteel
Towards complex prototyping
Custom MATLAB/COMSOL function
MATLAB/COMSOL/LiveLink
Flywheel profile optimization +
export
rotor generator and assembly
rotor analysis AMB construction
generator
1
2
3
Rotor
AMB Path
Rotor Stator
Coils
Rotor eigenfrequency analysis
Surface displacement in nanometers for rotational speeds: a) 3000 rpm; b) 15000 rpm.
Other aspects and future work
• Components to be included:– motor/generator– AMB control– Rotor dynamics
• Extension of current study stage:– Model of the complete system– Thermal, Magnetic and Aerodynamic
aspects• Multiobjective optimization
Conclusions
• COMSOL allows to perform a number of required analysis
• Custom methods for design, optimisation, integration and AMB generation
• On the base of construction properties the AMB and rotor dynamics can be considered
• It is possible to build the complete 3D virtual prototype?
Thank you for your attention