Modelling and Control of Heat Exchanger In Piping system
Santala, Samuli (2017)
2017
Automaatiotekniikka
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2017-05-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201704061254
https://urn.fi/URN:NBN:fi:tty-201704061254
Tiivistelmä
In this thesis, two nonlinear heating system models are developed to test how their linearizations can be used in their controller designs. Also in this thesis, the piping system design factors that affect the controller designs are considered. The controllers designed are single-tuning (linear) PID-controllers. The developed system models are numerically simulated using MATLAB and Simulink.
Based on the developed system models and their simulation results, a well-performing linear controller can be designed using the linearizations. The controller's performance depends on the system model's nonlinearity at the temperature range used. The local margins are used to asses the local stabilities at the nonlinear system models' equilibrium points. The local margins are determined by their linearizations and the controller tuning parameters. Based on the simulation results, a linear controller can be tuned such, that the local margins are large enough to buffer the potentially destabilizing effects of the nonlinearities inside a temperature range used.
The system model's nonlinearity is greatly affected by the piping system design. The most important piping system design consideration is, unsurprisingly, the control valve. It can linearize the nonlinear system model characteristic significantly, which improves the linear controller's ability to perform well. Other significant piping system design factors are the valve actuator and the temperature sensor time constants, which dominate the dynamics of the developed system models.
Based on the developed system models and their simulation results, a well-performing linear controller can be designed using the linearizations. The controller's performance depends on the system model's nonlinearity at the temperature range used. The local margins are used to asses the local stabilities at the nonlinear system models' equilibrium points. The local margins are determined by their linearizations and the controller tuning parameters. Based on the simulation results, a linear controller can be tuned such, that the local margins are large enough to buffer the potentially destabilizing effects of the nonlinearities inside a temperature range used.
The system model's nonlinearity is greatly affected by the piping system design. The most important piping system design consideration is, unsurprisingly, the control valve. It can linearize the nonlinear system model characteristic significantly, which improves the linear controller's ability to perform well. Other significant piping system design factors are the valve actuator and the temperature sensor time constants, which dominate the dynamics of the developed system models.