Active fault tolerant PD control law for PWRs under external disturbance

Abstract

NPP is a complex time varying nonlinear system that have to operate under severe constraints while complying with safe operating conditions in order to ensure the power demand and prevent the plant from contingent network instability. Towards this goal, this paper proposes the design of active fault tolerant proportional and derivative (PD) control law for Pressurized Water Reactors (PWRs) under external disturbance. To achieve this, the reactor core’s nonlinear dynamic is transformed into input/output (I/O) second-order system with respect to the power level. Based on the new model, a control strategy is proposed that aims to detect, identify, estimate and compensate for actuator faults. The stability of the system is proven using Lyapunov stability theory, where a quadruple Linear Matrix Inequalities (LMIs) system is derived to provide gains for both the control law and observer. Numerical simulations are conducted to assess the performance of the newly built control strategy and a comparison has been made. It follows that the designed controller not only effectively manages faults and external disturbances but also demonstrate exceptional performance when compared to the model-free controller (MFC) and the L₁ adaptive robust controller (L₁ ARC).