scholarly journals Unified Approach for Robust Stability Analysis of Buck Converters with Discrete-Time Sliding Mode Control

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yanmin Wang ◽  
Yang Ge ◽  
Ping Zhang ◽  
Guangxin Duan
Keyword(s):  
Robust Stability ◽  
Discrete Time ◽  
Controller Design ◽  
Sliding Mode ◽  
Buck Converters ◽  
Unified Approach ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Control Approach ◽  
Robust Stability Analysis

This paper proposes a novel discrete-time sliding mode (DTSM) control approach to address the robust stability problem of buck converters with multiple disturbances. The contributions lie in the “unified” modelling and controller design. In modelling, all the possible model uncertainties and external disturbances are considered and further classified into two cases. It can also be extended to the situations with individual/several disturbances. While for the controller design, differing from the traditional DTSM based on the nominal model, the disturbances are directly introduced in the process, giving the robust stability condition and four new regulation subranges. It is suitable for both nominal and perturbed systems. Finally, the influences of the sampling time and disturbances on the control performance are investigated. Simulations and experiments confirm the benefits of the unified approach with greater accuracy and wider applications.

scholarly journals Handling Model and Implementation Uncertainties via an Adaptive Discrete Sliding Mode Controller Design

2016 ◽  
Author(s):  
Mohammad Reza Amini ◽  
Mahdi Shahbakhti ◽  
Selina Pan ◽  
J. Karl Hedrick
Keyword(s):  
Adaptive Control ◽  
Controller Design ◽  
Sliding Mode ◽  
Electronic Control Unit ◽  
Control Technique ◽  
Propagation Mechanism ◽  
Sliding Mode Controller ◽  
Model Uncertainties ◽  
Control Approach ◽  
The Impact

Analog-to-digital conversion (ADC) and uncertainties in modeling the plant dynamics are the main sources of imprecisions in the design cycle of model-based controllers. These implementation and model uncertainties should be addressed in the early stages of the controller design, otherwise they could lead to failure in the controller performance and consequently increase the time and cost required for completing the controller verification and validation (V&V) with more iterative loops. In this paper, a new control approach is developed based on a nonlinear discrete sliding mode controller (DSMC) formulation to mitigate the ADC imprecisions and model uncertainties. To this end, a DSMC design is developed against implementation imprecisions by incorporating the knowledge of ADC uncertainties on control inputs via an online uncertainty prediction and propagation mechanism. Next, a generic online adaptive law will be derived to compensate for the impact of an unknown parameter in the controller equations that is assumed to represent the model uncertainty. The final proposed controller is an integrated adaptive DSMC with robustness to implementation and model uncertainties that includes (i) an online ADC uncertainty mechanism, and (ii) an online adaptation law. The proposed adaptive control approach is evaluated on a nonlinear automotive engine control problem in real-time using a processor-in-the-loop (PIL) setup with an actual electronic control unit (ECU). The results reveal that the proposed adaptive control technique removes the uncertainty in the model fast, and significantly improves the robustness of the controllers to ADC imprecisions. This provides up to 60% improvement in the performance of the controller under implementation and model uncertainties compared to a baseline DSMC, in which there are no incorporated ADC imprecisions.

scholarly journals Adaptive Global Sliding Mode Controller Design for Perturbed DC-DC Buck Converters

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1249
Author(s):  
Saleh Mobayen ◽  
Farhad Bayat ◽  
Chun-Chi Lai ◽  
Asghar Taheri ◽  
Afef Fekih
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Lyapunov Stability Theory ◽  
Buck Converter ◽  
Control Law ◽  
Control Input ◽  
Buck Converters ◽  
Tracking Accuracy ◽  
Control Approach ◽  
Efficient Suppression

This paper proposes a novel adaptive intelligent global sliding mode control for the tracking control of a DC-DC buck converter with time-varying uncertainties/disturbances. The proposed control law is formulated using a switching surface that eliminates the reaching phase and ensures the existence of the sliding action from the start. The control law is derived based on the Lyapunov stability theory. The effectiveness of the proposed approach is illustrated via high-fidelity simulations by means of Simscape simulation environment in MATLAB. Satisfactory tracking accuracy, efficient suppression of the chattering phenomenon in the control input, and high robustness against uncertainties/disturbances are among the attributes of the proposed control approach.

A fault-tolerant attitude tracking control of spacecraft using an anti-unwinding robust nonlinear disturbance observer

2019 ◽  
Vol 233 (16) ◽  
pp. 6005-6018 ◽  
Author(s):  
Syed Muhammad Amrr ◽  
M Nabi ◽  
Pyare Mohan Tiwari
Keyword(s):  
Disturbance Observer ◽  
Controller Design ◽  
Simulation Analysis ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Actuator Faults ◽  
External Disturbances ◽  
Nonlinear Disturbance Observer ◽  
Attitude Tracking ◽  
Nonlinear Disturbance

This paper investigates the application of an integral sliding mode control with a robust nonlinear disturbance observer to obtain an anti-unwinding spacecraft attitude tracking response with robustness against external disturbances, inertia matrix uncertainties, and actuator faults. In the controller design, external disturbances, uncertainties, and actuator faults are lumped together and estimated by the robust nonlinear disturbance observer. The proposed robust nonlinear disturbance observer guarantees the convergence of estimated lumped disturbance error to origin in finite time. The estimated disturbance is then used in the controller as a feed-forward compensator. Further, an adaptive law is also incorporated in the proposed controller to ensure additional robustness. The stability of the overall system and anti-unwinding characteristic are proved using the Lyapunov stability theory. Finally, numerical simulation analysis is performed in the presence of all the sources of lumped disturbances. It is observed that the proposed control strategy is ensuring higher accuracy, good steady-state precision, and eliminates the unwinding phenomenon.

scholarly journals Disturbance Observer-Based Nonsingular Terminal Sliding Mode Control for Spacecraft Electromagnetic Docking

2020 ◽  
Vol 2020 ◽  
pp. 1-20
Author(s):  
Jinghui Zhang ◽  
Guoqiang Zeng ◽  
Shifeng Zhang
Keyword(s):  
Sliding Mode Control ◽  
Magnetic Moment ◽  
Disturbance Observer ◽  
Field Model ◽  
Sliding Mode ◽  
Far Field ◽  
Model Uncertainties ◽  
External Disturbances ◽  
Control Scheme ◽  
On Line

This paper presents a novel nonlinear sliding mode control scheme that combines on-line model modification, a nonlinear sliding mode controller, and a disturbance observer to solve the essential problems in spacecraft electromagnetic docking control, such as model uncertainties, unknown external disturbances, and inherent strong nonlinearity and coupling. An improved far-field model of electromagnetic force which is much more accurate than the widely used far-field model is proposed to enable the model parameters to be on-line self-adjusting. Then, the relationship between magnetic moment allocation and energy consumption is derived, and the optimal direction of the magnetic moment vector is obtained. Based on the proposed improved far-field model and the research results of magnetic moment allocation law, a fast-nonsingular terminal mode controller driven by a disturbance observer is designed in the presence of model uncertainties and external disturbances. The proposed control method is guaranteed to be chattering-free and to possess superior properties such as finite-time convergence, high-precision tracking, and strong robustness. Two simulation scenarios are conducted to illustrate the necessity of modifying the far-field model and the effectiveness of the proposed control scheme. The simulation results indicate the realization of electromagnetic soft docking and validate the merits of the proposed control scheme. In the end of this paper, some conclusions are drawn.

Control of Discrete Time Chaotic Systems via Combination of Linear and Nonlinear Dynamic Programming

2014 ◽  
Vol 10 (1) ◽  
Author(s):  
Kaveh Merat ◽  
Jafar Abbaszadeh Chekan ◽  
Hassan Salarieh ◽  
Aria Alasty
Keyword(s):  
Discrete Time ◽  
Control Method ◽  
Controller Design ◽  
Chaotic Behavior ◽  
Noise Signal ◽  
Delayed Feedback Control ◽  
Optimal Controller ◽  
Clustering Method ◽  
Control Approach ◽  
Feedback Control Method

In this article by introducing and subsequently applying the Min–Max method, chaos has been suppressed in discrete time systems. By using this nonlinear technique, the chaotic behavior of Behrens–Feichtinger model is stabilized on its first and second-order unstable fixed points (UFP) in presence and absence of noise signal. In this step, a comparison has also been carried out among the proposed Min–Max controller and the Pyragas delayed feedback control method. Next, to reduce the computation required for controller design, the clustering method has been introduced as a quantization method in the Min–Max control approach. To improve the performance of the acquired controller through clustering method obtained with the Min–Max method, a linear optimal controller is also introduced and combined with the previously discussed nonlinear control law. The resultant combined controller has been applied on the Henon map and through comparison with both Pyragas controller, and the linear optimal controller alone, its advantages are discussed.

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