Novel anti-disturbance fast terminal sliding mode control with improved quick reaching law for DC-DC buck converter

Abstract

In order to improve the performance and suppress the chattering problem of variable structure control system, a nonlinear novel quick reaching law with dynamic power term is suggested, which could enhance the convergence rate whenever the system state position is near to or far from the manifold. Furthermore, a novel fast terminal sliding surface with additional nonlinear terms is developed and designed. The combination of these structure propositions can minimize both the reaching time and sliding time convergence. The finite-time stability of the proposed control paradigm is demonstrated via the Lyapunov criteria method. Moreover, in order to see the superior performance of the compound control, a disturbed DC-DC buck converter is selected as plant in this work. In addition, the extended state observer is designed and added in feedforward path of control law of sliding mode structure. In order to estimate the unknown uncertainties, the results demonstrate that the nonlinear novel fast terminal sliding mode with variable quick reaching law brings the system at equilibrium point more rapidly than the traditional manifolds and reaching laws. More than that, the closed-loop system performance has better transient response, lower steady state error and lesser sensitivity to disturbances.