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.

In this article, in order to minimize response time and enhance anti-disturbance performance of parmanent magnet synchronous motor, a global integral terminal sliding mode control based on improved quick reaching law (GITSMC-QRL) is developed. This novel reaching law has two terms which play a key role of bringing state trajectory to sliding surface as quick as possible whenever the system is close to or far from the manifold. The proposed controller cannot only speed up the convergence rate, but also has ability to suppress the chattering and ensure finite time stability. In order to avoid the chattering phenomenon caused by load disturbances and high switching gain of sliding mode control, an extended hyperbolic tangent state observer is designed as feedforward compensation compensator that is added to GITSMC. Finally, the novel scheme is validated on paremanent magnet synchronous motor (PMSM) drive through simulation, and the comparative results in various conditions show the robustness, the feasibility and the effectiveness of the proposed controller.

No abstract

This article provides a systematic approach for synthesizing a novel robust synergetic control mechanism. This controller employs a dynamic global terminal synergetic surface with additional sinusoidal function. The overall macrovariable gives the system a rapid approaching rate, maintains the finite time stability, and provides a chattering-free control law. The stability analysis is validated for any uncertain second-order system via indirect approach of Lyapunov theorems. Furthermore, a hyperbolic tangent nonlinear disturbance observer is designed in order to estimate any lumped disturbance. The feasibility and the effectiveness of the proposed composite control law is tested and evaluated through simulations for simple model, wind turbine system and DC-DC buck converter. Finally, the simulation results show that the presented dynamic global terminal synergetic control–based hyperbolic tangent nonlinear disturbance observer can effectively reject the disturbances, enhance the robustness, and guarantee the tracking accuracy and rapidity.