scholarly journals Discrete-time nonlinear controller synthesis by input/output linearization

AIChE Journal ◽  
1992 ◽  
Vol 38 (12) ◽  
pp. 1923-1945 ◽  
Author(s):  
Masoud Soroush ◽  
Costas Kravaris
Keyword(s):  
Discrete Time ◽  
Controller Synthesis ◽  
Input Output ◽  
Nonlinear Controller ◽  
Input Output Linearization

Nonlinear coordinated control design of generator excitation and static var compensator for power system via input-output linearization

2020 ◽  
pp. 014233122096436
Author(s):  
Salma Keskes ◽  
Souhir Sallem ◽  
Mohamed Ben Ali Kammoun
Keyword(s):  
Power System ◽  
Single Machine ◽  
Short Circuit ◽  
Synchronous Generator ◽  
Voltage Regulation ◽  
Static Var Compensator ◽  
Input Output ◽  
Nonlinear Controller ◽  
Single Machine Infinite Bus ◽  
Input Output Linearization

This paper proposes a nonlinear coordinated controller for a single machine infinite bus power system. The later consists of a synchronous generator connected to the infinite bus via transmission lines, which are equipped with a static var compensator. The proposed control strategy aims to control simultaneously the excitation system of the synchronous generator and the static var compensator in order to improve transient stability and voltage regulation. The input output linearization theory and pole-assignment technique are employed to design the nonlinear controller. The controller’s performance in single machine infinite bus power system is then examined using simulation studies when the studied power system is subjected to three-phase short circuit with a 100ms duration. The results validate the efficiency of the proposed controller, which is based mainly on the good regulation of the static var compensator voltage with removing the static error after fault elimination.

scholarly journals Robust Discrete-Time Nonlinear Attitude Stabilization of a Quadrotor UAV Subject to Time-Varying Disturbances

2021 ◽  
Author(s):  
Fatih Adiguzel ◽  
Tarik Veli Mumcu
Keyword(s):  
Discrete Time ◽  
Disturbance Observer ◽  
Uncertain System ◽  
Time Varying ◽  
Input Output ◽  
Parameter Uncertainties ◽  
Nonlinear Disturbance Observer ◽  
Nonlinear Disturbance ◽  
Quadrotor System ◽  
Input Output Linearization

A discrete-time improved input/output linearization controller based on a nonlinear disturbance observer is considered to secure the stability of a four-rotor unmanned aerial vehicle under constant and time-varying disturbances, as well as uncertain system parameters for its attitude behaviour. Due to the nature of the quadrotor system, it contains the most extreme high level of nonlinearities, system parameter uncertainties (perturbations), and it has to cope with external disturbances that change over time. In this context, an offset-less tracking for the quadrotor system is provided with the input/output linearization controller together with a discrete-time pre-controller. In addition, the robustness of the system is increased with a discrete-time nonlinear disturbance observer for time-varying disturbances affecting the system. The main contribution of this study is to provide highly nonlinearities cancellation to guarantee the aircraft attitude stability and to propose a robust control structure in discrete-time, considering all uncertainties. Various simulation studies have been carried out to illustrate the robustness and effectiveness of the proposed controller structure.

scholarly journals Digital Control of a Buck Converter Based on Input-Output Linearization. An Interpretation Using Discrete-Time Sliding Control Theory

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2738
Author(s):  
Enric Vidal-Idiarte ◽  
Carlos Restrepo ◽  
Abdelali El Aroudi ◽  
Javier Calvente ◽  
Roberto Giral
Keyword(s):  
Discrete Time ◽  
Digital Control ◽  
Output Voltage ◽  
Power Converter ◽  
Current Control ◽  
Buck Converter ◽  
Control Loop ◽  
Input Output ◽  
Analysis And Design ◽  
Input Output Linearization

This paper presents the analysis and design of a PWM nonlinear digital control of a buck converter based on input-output linearization. The control employs a discrete-time bilinear model of the power converter for continuous conduction mode operation (CCM) to create an internal current control loop wherein the inductor current error with respect to its reference decreases to zero in geometric progression. This internal loop is as a constant frequency discrete-time sliding mode control loop with a parameter that allows adjusting how fast the error is driven to zero. Subsequently, an outer voltage loop designed by linear techniques provides the reference of the inner current loop to regulate the converter output voltage. The two-loop control offers a fast transient response and a high regulation degree of the output voltage in front of reference changes and disturbances in the input voltage and output load. The experimental results are in good agreement with both theoretical predictions and PSIM simulations.

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