HGO-based adaptive super-twisting sliding mode power level control with prescribed performance for modular high-temperature gas-cooled reactors

Abstract

This paper proposes a high-gain observer-based adaptive super-twisting sliding mode control strategy with prescribed performance (HGO-ASTSMCS-PP) for the power level of a modular high-temperature gas-cooled reactor (MHTGR). The dynamic model of the MHTGR is firstly described. By using this established model, a high-gain observer is constructed to recover the unmeasured states including relative density of delayed neutron precursor and reactor core temperature in real time. On the basis of the recovering values from the HGO, an adaptive super-twisting sliding mode control method with prescribed performance is designed. The super-twisting sliding mode control approach is adopted to improve control performance of power level for a MHTGR and suppress high-frequency chattering effects simultaneously. An adaptive mechanism is introduced to tune the control gains online so as to overcome the overestimation of the unknown disturbance boundary. In addition, by error transformation and introduction of performance function, the prescribed control performance of power level is guaranteed, which implies that the desirable convergence rate, steady power error, and maximum overshoot can be prescribed in advance. It is verified through Lyapunov stability theory that the overall closed-loop control system is globally uniformly ultimately bounded (GUUB). Finally, simulation and comparison results are presented to reveal the effectiveness of the proposed control scheme in terms of the steady and dynamic performance.