Dynamic modeling and Model Predictive Control of a vapor compression system
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
The focus of this thesis was on the development of a dynamic modeling capability for a vapor compression system along with the implementation of advanced multivariable control techniques on the resulting model.
Individual component models for a typical vapor compression system were developed based on most recent and acknowledged publications within the field of thermodynamics. Parameter properties such as pressure, temperature, enthalpy etc. for each component were connected to detailed thermodynamic tables by algorithms programmed in MATLAB, thus creating a fully dynamic environment. The separate component models were then interconnected and an overall model for the complete system was implemented in SIMULINK. An advanced control technique known as Model Predictive Control (MPC) along with an open-source QP solver was then applied on the system. The MPC-controller requires the complete state information to be available for feedback and since this is often either very expensive (requires a great number of sensors) or at times even impossible (difficult to measure), a full-state observer was implemented. The MPC-controller was designed to keep certain system temperatures within tight bands while still being able to respond to varying cooling set-points. The control architecture was successful in achieving the control objective, i.e. it was shown to be adaptable in order to reflect changes in environmental conditions. Cooling demands were met and the temperatures were successfully kept within given boundaries.
Place, publisher, year, edition, pages
2012. , 152 p.
Model Predictive Control, MPC, Vapor Compression Systems, Modeling
IdentifiersURN: urn:nbn:se:liu:diva-76352ISRN: LiTH-ISY-EX--12/4552--SEOAI: oai:DiVA.org:liu-76352DiVA: diva2:513993
Subject / course
2012-03-28, Algoritmen, Linköpings Universitet, Linköping, 10:00 (Swedish)
Axelsson, PatrikLundkvist, Joakim