Fuzzy-adapted recursive sliding-mode controller design for a nuclear power plant control

In this paper, a multi-input multi-output fuzzy-adapted recursive sliding-mode controller (FARSMC) is designed for an advanced boiling water reactor (ABWR) nuclear power plant, to control reactor pressure, reactor water level and turbine power. The FARSMC is intended to replace the existing conventional controllers for the power range of 70% to 100% rated power. The controller has a recursive form that treats model uncertainty and external disturbances in an implicit way. Thus there is no need to specify uncertainties and disturbances for this controller design in advance. Moreover, the chattering problem common among conventional sliding-mode controllers is completely removed by this recursive sliding-mode control (RSMC) algorithm. The performance of the resulting RSMC is further improved by parameter adaptation using fuzzy logic algorithm, resulting in fuzzy-adapted RSMC (FARSMC). To apply RSMC technique, the original nonlinear plant model is first transformed to a canonical form. Simulations of the simplified ABWR model with the designed FARSMC indicate that FARSMC may result in better performance than the existing PI controllers in that the plant transient responses to the desired output step change have shorter settling time and smaller magnitude overshoot/undershoot. The control actions of the FARSMC are milder than those from the PI controllers. Robustness of the FARSMC with respect to power level variation and capability to reject external disturbances is also achieved. Successful fuzzy adapted sliding-mode controller design and implementation on the model shows that FARSMC may be a practical choice for nuclear power plant control.