Control of a nuclear steam generator using feedback-feedforward LQG controller

Steam Generator (SG) is a major component in a nuclear power plant. Poor control of a nuclear steam generator can lead to frequent reactor shutdowns or it can damage turbine blades. To avoid such costly reactor shutdowns, there is a need to systematically investigate the problem of controlling the water level in the steam generator. In this work, we have proposed a novel concept of feedback-feedforward Linear Quadratic Gaussian (LQG) control scheme to achieve efficient servo and regulatory control of SG. The benchmark nonlinear dynamic model proposed by Astrom has been simulated using MATLAB to carry out simulation studies. The major disturbance in a steam generator is steam demand and the proposed controller is capable of initiating a feedforward action in response to steam demand changes. This approach employs a Kalman filter for state estimation and uses estimation error feedback to achieve offset free closed-loop behavior. The closed-loop responses can be shaped using additional filters introduced to mitigate sudden changes in the setpoint and unmeasured disturbances. Finally, simulation results shows the effectiveness and the improved performance of the proposed method.