The goal of this dissertation is to evaluate the effectiveness of model predictive control (MPC)
for a magnetically suspended flywheel energy storage uninterruptible power supply (FlyUPS).
The reason this research topic was selected was to determine if an advanced control technique
such as MPC could perform better than a classical control approach such as decentralised
Proportional-plus-Differential (PD) control.
Based on a literature study of the FlyUPS system and the MPC strategies available, two MPC
strategies were used to design two possible MPC controllers were designed for the FlyUPS,
namely a classical MPC algorithm that incorporates optimisation techniques and the MPC
algorithm used in the MATLAB® MPC toolbox™. In order to take the restrictions of the system
into consideration, the model used to derive the controllers was reduced to an order of ten
according to the Hankel singular value decomposition of the model.
Simulation results indicated that the first controller based on a classical MPC algorithm and
optimisation techniques was not verified as a viable control strategy to be implemented on the
physical FlyUPS system due to difficulties obtaining the desired response. The second
controller derived using the MATLAB® MPC toolbox™ was verified to be a viable control
strategy for the FlyUPS by delivering good performance in simulation.
The verified MPC controller was then implemented on the FlyUPS. This implementation was
then analysed in order to validate that the controller operates as expected through a
comparison of the simulation and implementation results. Further analysis was then done by
comparing the performance of MPC with decentralised PD control in order to determine the
advantages and limitations of using MPC on the FlyUPS.
The advantages indicated by the evaluation include the simplicity of the design of the controller
that follows directly from the specifications of the system and the dynamics of the system, and
the good performance of the controller within the parameters of the controller design. The
limitations identified during this evaluation include the high computational load that requires a
relatively long execution time, and the inability of the MPC controller to adapt to unmodelled
system dynamics.
Based on this evaluation MPC can be seen as a viable control strategy for the FlyUPS, however
more research is needed to optimise the MPC approach to yield significant advantages over
other control techniques such as decentralised PD control. / Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/8601 |
| Date | January 2012 |
| Creators | Aucamp, Christiaan Daniël |
| Publisher | North-West University |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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