Optimal power control of a three-shaft Brayton cycle based power conversion unit

Abstract

The aim of this study is to develop a control system that optimally controls the power output of a Brayton cycle based power plant. The original design of the PBMR power plant is considered. It uses helium gas as working fluid. The power output of the system can be manipulated by changing the helium inventory to the gas cycle. A linear model of the power plant is derived and modelled in Simulink®. This linear model is used as an evaluation platform for different control strategies. Four actuators are identified that are responsible for manipulating the helium inventory. They are: A booster tank A gas cycle bypass control valve Low-pressure injection at the low-pressure side of the system. High-pressure extraction at the high-pressure side of the system The control system has to intelligently generate set point values for each of these actuators to eventually control the power output. Two control strategies namely PID control and Fuzzy control are investigated in this study. An optimisation technique called Genetic Algorithms is used to adapt the gain constants of the Fuzzy control strategy. This resulted in an optimal power control system for the Brayton cycle based power plant.