Order Sliding Mode Research Articles

Using Adaptive Second Order Sliding Mode to Improve Power Control of a Counter-Rotating Wind Turbine under Grid Disturbances

This work presents a new control strategy for counter-rotating wind turbine (CRWT) driven doubly-fed induction generator (DFIG) under grid disturbances, such as unbalanced network voltage scenarios. The proposed strategy based on the power control used dynamic gains second order sliding mode control (SOSMC). The power control of a DFIG by SOSMC widely based on the super-twisting (ST) algorithm with invariable parameters and sign functions. The proposed control method consists in using dynamic-parameters ST algorithm that ensures a better result than a conventional strategy. The proposed control scheme used 2 sliding surfaces such as reactive and active powers to control them. Also, the sign functions are replaced by saturation (sat) functions in order to minimize the chattering problems. Simulation results depicted in this research article have confirmed the good usefulness and effectiveness of the proposed adaptive super-twisting algorithm of the CRWT system during grid disturbances.

Load Frequency Control of Three area Multi-Unit Deregulated Power System with FOSMC and Performance analysis using Regulation constant

This paper presents three area multi-unit Deregulated Power System (DPS) for Load Frequency Control (LFC) using Fractional Order Sliding Mode Controller (FOSMC) along with Thyristor Controlled Phase Shifters (TCPS) and Superconducting Magnetic Energy Storage (SMES) combination. The FOSMC can be used to overcome nonlinearities and uncertainties of the system for bilateral and unilateral transactions under different Step Load Perturbations (SLPs). The deregulated power system performance is analyzed for different Regulation constants (R) such as 1.8, 2.4 and 3.0. For stabilization of oscillations in frequency and to stabilize the deregulated power system dynamically for different SLPs, TCPS is incorporated with the tie line in series and SMES is used as an energy storage unit. The dynamic responses of LFC problems have been simulated and analyzed with MATLAB/Simulink-based computer simulations. Further simulation results have also been tabulated as a comparative performance with respect to peak overshoot and settling time.

Fractional Order Sliding Mode Control Design for a Buck Converter Feeding Resistive Power Loads

Standalone DC micro-grid requires highly efficient power converters with high performance robust controllers. This research work deals with the hardware implementation of a load side buck converter and its control system integrated in a DC micro-grid system. This paper presents a novel fractional order sliding mode control (FSMC) method for voltage regulation of a buck converter feeding a constant power load. FSMC controller is derived based on the average state space model of the buck converter and its stability is verified using Lyapunov theorem. Finally, the FSMC controller is implemented using Arduino mega 2560 processor and the obtained results are compared with classical sliding mode control (SMC), proportional, integral, derivative (PID) control and fractional order PID control system (FOPID under constant and variable resistive loading.

Robust maximum power point tracking control for photovoltaic system based on second order sliding-mode

<div data-canvas-width="397.1720469663374">This paper proposes a control approach of a maximum power point of a photovoltaic (PV) system using the second order sliding mode approach. The main objective of the proposed paper is to track the maximum power point (MPP) using super twisting algorithm (STA) with a one-loop control method and augment efficiency of the output power system. The structure of a proposed approach is simple and robust aging the atmospheric changes. Such control approach solution has several advantages such as simple implementation, robustness; reduce the chattering phenomenon and good dynamic response compared to traditional first-order sliding mode control algorithm. The controller circuit adapts the duty cycle of the switch electronic device of the DC/DC converter to search maximum power point tracking as a function of evolution of the power input. The effectiveness and feasibility of the proposed control are verified by simulation in MATLAB /Simulink environment and dSPACE-based hardware in loop platform.</div>

Robust maximum power point tracking control for photovoltaic system based on second order sliding-mode

Robust maximum power point tracking control for photovoltaic system based on second order sliding-mode

Second Order Sliding Mode Control of Oscillating Water Column Wave Energy Converters for Power Improvement

Ocean wave energy is a renewable energy which remains too costly for large-scale electricity generation. The oscillating water column (OWC) wave energy converter (WEC) is a promising device-type with a rectifying air turbine and generator which convert alternating airflow induced by the water motion into kinetic energy then into electric energy. Applying control at each stage of energy conversion could increase the electric energy output of the device. As researchers overcome the modeling challenges of OWC, such as the nonlinearities due to air compressibility and power take-off (PTO) dynamics, we can integrate specific control algorithms to test their ability to improve the efficiency of the OWC. Herein, we present a state-space model of an array of OWC WECs restricted to heave motion with nonlinear PTO dynamics. We apply second-order sliding mode control (SMC) which commands a smooth torque signal to a direct-drive generator to maintain a reference turbine angular velocity. Because the algorithm can yield high turbine torques, we investigate a simple feed-forward relation for the control of a valve to limit the turbine airflow and discard mechanical power. We find that implementing the SMC algorithm and valve control can improve electric energy conversion most effectively in less energetic sea states.

The Design of Quasi-Optimal Higher Order Sliding Mode Control via Disturbance Observer and Switching-Gain Adaptation

In this paper, a quasi-optimal higher order sliding mode control (HOSMC) scheme is designed using disturbance observer (DOB) and adaptive techniques. The overall HOSMC scheme is constituted by three portions: 1) a switch-based quasi-optimal control law that ensures rapid finite-time stabilization of the origin, producing a nominally uncertainty-free system, based on a perturbed chain of integrators; 2) a DOB which estimates the lumped uncertainties with lower frequencies; and 3) an adaptive controller designed to deal with the fast-varying terms of these lumped uncertainties over the pass-band of the DOB. Since the adaptive controller and the DOB work in a cooperative manner, the only requirement is that the switching gain be greater than the bound of the DOB estimation error, instead of the bound of the lumped uncertainties. As a consequence, overestimation in the adaptive controller can be avoided by resorting to the equivalent control. Simulation results confirm the capabilities of the proposed control strategy.

WITHDRAWN: Prediction of epileptic seizures using Grey Wolf Optimized Model Driven mathematical approach

Abstract Epilepsy is the most dangerous neurological disorder which is characterized by unprovoked electrical events in the brain, called seizures. Epileptic patients are affected neurologically, cognitively, psychologically and societal behaviourally. It is crucial to understand the temporal dynamics of epileptic EEGs involving the inception, propagation and termination of seizures. In this work, we construct a data analytics approach in conjunction with a neural based mathematical model. First the modelling of seizure EEGs are obtained using an Enhanced Wendling (EW) model. Next a data driven, Grey Wolf Optimized Model Driven (GWO-MD) approach is modelled for tracking the seizure events. Finally, a Closed Loop Control (CLC) framework which has a Fractional Order Sliding Mode Controller (FOSMC) combined with a Genetic Algorithm based Cascade Forward Back Propagation network (GA-CFBP) is constructed for controlling the seizure EEGs. The proposed model-driven mathematical approach is validated using two distinct databases such as traditional CHB-MIT and a private real time SRM database. Empirical results were obtained from 16 patients 69 EEG recordings exhibit that the proposed approach accomplishes close to the real time recordings. Tracking of the seizure states, predicting and controlling results of the proposed model is exceptionally better than the state-of-the-art approaches.

Conventional and Second Order Sliding Mode Control of Permanent Magnet Synchronous Motor Fed by Direct Matrix Converter: Comparative Study

The main objective of this work revolves around the design of second order sliding mode controllers (SOSMC) based on the super twisting algorithm (STA) for asynchronous permanent magnet motor (PMSM) fed by a direct matrix converter (DMC), in order to improve the effectiveness of the considered drive system. The SOSMC was selected to minimize the chattering phenomenon caused by the conventional sliding mode controller (SMC), as well to decrease the level of total harmonic distortion (THD) produced by the drive system. In addition, the literature has taken a great interest in the STA due to its robustness to modeling errors and to external disturbances. Furthermore, due to its low conduction losses, the space vector approach was designated as a switching law to control the DMC. In addition, the topology and design method of the damped passive filter, which allows improvement of the waveform and attenuation of the harmonics of the input current, have been detailed. Finally, to discover the strengths and weaknesses of the proposed control approach based on SOSMC, a comparative study between the latter and that using the conventional SMC was executed. The results obtained confirm the effectiveness of SOSMC over the conventional SMC under different operating conditions.

Design and Implementation of High Order Sliding Mode Control for PEMFC Power System

Fuel cells are considered as one of the most promising methods to produce electrical energy due to its high-efficiency level that reaches up to 50%, as well as high reliability with no polluting effects. However, scientists and researchers are interested more in proton exchange membrane fuel cells (PEMFCs). Thus, it has been considered as an ideal solution to many engineering applications. The main aim of this work is to keep the PEMFC operating at an adequate power point. To this end, conventional first-order sliding mode control (SMC) is used. However, the chattering phenomenon, which is caused by the SMC leads to a low control accuracy and heat loss in the energy circuits. In order to overcome these drawbacks, quasi-continuous high order sliding mode control (QC-HOSM) is proposed so as to improve the power quality and performance. The control stability is proven via the Lyapunov theory. The closed-loop system consists of a PEM fuel cell, a step-up converter, a DSPACE DS1104, SMC and QC-HOSM algorithms and a variable load resistance. In order to demonstrate the effectiveness of the proposed control scheme, experimental results are compared with the conventional SMC. The obtained results show that a chattering reduction of 84% could be achieved using the proposed method.

DESIGN OF MODIFIED SECOND ORDER SLIDING MODE CONTROLLER BASED ON ST ALGORITHM FOR BLOOD GLUCOSE REGULATION SYSTEMS

The type1 of diabetes is a chronic situation characterized by abnormally high glucose levels in the blood. Persons with diabetes characterized by no insulin secretion in the pancreas (ß-cell) which also known as insulin-dependent diabetic Mellitus (IDDM). In order to keep the levels of glucose in blood near the normal ranges (70-110mg/dl), the diabetic patients needed to inject by external insulin from time to time. In this paper, a Modified Second Order Sliding Mode Controller (MSOSMC) has been developed to control the concentration of blood glucose levels under a disturbing meal. The parameters of the suggested design controller are optimized by using chaotic particle swarm optimization(CPSO) technique, the model which is used to represent the artificial pancreas is a minimal model for Bergman. The simulation was performed on a MATLAB/ SIMULINK to verify the performance of the suggested controller. The results showed the effectiveness of the proposed MSOSMC in controlling the behavior of glucose deviation to a sudden rise in blood glucose.

Nested High Order Sliding Mode Controller with Back-EMF Sliding Mode Observer for a Brushless Direct Current Motor

This work presents a nested super-twisting second-order sliding mode speed controller for a brushless direct current motor with a high order sliding mode observer used for back electromotive force (back-EMF) estimation. Due to the trapezoidal nature of the back-EMF, a modified Park transformation is used in order to achieve proper field orientation. Such transformation requires information from the back-EMF that is not accessible. A second-order sliding mode observer is used to estimate the back electromotive forces needed in the modified transformation. Sliding mode control is known to be robust to matched uncertain disturbances and parametric variations but it is prone to unmatched perturbations that affect the performance of the system. A nested scheme is used to improve the response of the controller in presence of unmatched disturbances. Simulations performed under similar conditions to real-time experimentation show a good regulation of the rotor speed in terms of transient and steady-state responses along with a reduced torque ripple.

Marine Current Generators Multimachine System Based on High Order Sliding Mode Control

Marine Current Generators Multimachine System Based on High Order Sliding Mode Control

Application of Adaptive Neuro-Fuzzy Inference Rule-based Controller in Hybrid Electric Vehicles

Designing of hybrid architecture has greater importance in the development of electric vehicles to enhance the life cycle of the battery, to protect from nonlinearities and uncertainties of electrical energy storage systems. The objective of this paper is to design and apply the Adaptive Neuro-Fuzzy Inference rule-based controller with the semi-empirical strategy to protect from nonlinearities, uncertainties, and to improve efficiency in electric vehicles. In this paper, a fully active Li-Ion battery/Electric Double-Layer supercapacitor hybrid energy storage system used to decouple Li-Ion battery/Electric Double-Layer Supercapacitor from Direct Current bus and to generate Li-Ion battery current reference online semi-empirical rule-based energy management strategy used. The Control system is designed with the Adaptive Neuro-Fuzzy Interface rule-based controller to reduce non-linearity and different uncertainties of the energy storage system with two outputs battery current and DC bus voltage are chosen to measure control system design, which is tested under heavy and light load conditions. Results are validated using MATLAB/Simulink and the performance of the Adaptive Neuro-Fuzzy Interface rule-based controller is 16.96% and 9.81% greater than Robust Fractional Order Sliding Mode Controller under heavy and light load conditions.

Designing of a Control Approach for Uncertain Fractional Order Systems with Indirect Adaptive Fuzzy Controller and Frational Order Sliding Mode

Designing of a Control Approach for Uncertain Fractional Order Systems with Indirect Adaptive Fuzzy Controller and Frational Order Sliding Mode

A General Framework for Switched and Variable Gain Higher Order Sliding Mode Control

Sliding mode control is a widely used approach in different application domains, due to its versatility and ease of implementation. As is well known, one of its most serious drawbacks is the presence of chattering. To alleviate this problem, higher order sliding mode (HOSM) approaches have been proposed, which also allow dealing with high relative degree plants. To gain more flexibility in the controller design and to boost performance, switched and variable-gain approaches are being developed for first and second-order sliding mode controllers. This article introduces a conceptual framework to merge the two aspects, providing a general methodology for the design and tuning of high-order sliding mode controllers. The main strength of the method is its generality, in that it accommodates a generic order r sliding mode controller, and it encompasses both continuous and discrete variation of the controller parameters, the latter giving rise to switched strategies. The properties of the closed-loop system are formally analyzed, and the effectiveness of the method is demonstrated in simulation on examples of switched and variable gain HOSM controllers.

Predefined-Time Output Stabilization With Second Order Sliding Mode Generation

In this article, a novel second order sliding mode control strategy is proposed for relative-degree-2 nonlinear uncertain single- input-single-output (SISO) systems. To design the strategy, the phase portrait of the second order system in normal form associated with the formulated sliding mode control problem is studied. A sliding surface switching between arcs of parabolas is conceived to ensure the convergence in a predefined-time to the desired second order sliding mode. Lyapunov-based analysis and the reformulation of LaSalle-Yoshizawa results for nonsmooth systems are used to prove the uniform finite-time stability of the equilibrium consisting in the second order sliding mode enforcement. This in turn allows to prove the asymptotic convergence of the original plant state to the origin in spite of the uncertainties.

Higher order sliding mode STATCOM control for power system stability improvement

The objective of this research is to design a higher order Sliding Mode Controller (SMC) for a Static Synchronous Compensator (STATCOM) and investigation of its implication on power system stability improvement. The theory of Super-Twisting–Sliding-Mode-Control (STSMC) is applied to determine the nonlinear control law of a STATCOM. The STSMC based control combines 2-sliding control and Robust Exact Differentiator (RED) which can efficiently mitigate the effect of external disturbance to the system The purpose of the application of the STSMC based control method is that it not only solves the chattering problem of classical SMC but also the derived control law is independent of system parameters. The efficacy of the design of the proposed STATCOM controller has been investigated in comparison to both the nonlinear (via exact linearization) and conventional (via approximate linearization) Linear Quadratic Regulator (LQR) based STATCOM controller. An IEEE type 14 bus multi-machine system has been taken into consideration to study the simulation results with regard to the transient stability improvement in multiple operating scenarios. It has been revealed from the simulation results that the proposed control scheme based on STSMC is more effective with respect to both the exact linearization based as well as approximately linearization based approach for the design of STATCOM controller. Furthermore, it has been abstracted that the STSMC based nonlinear STATCOM controller is competent to mitigate the dynamic instability of an electric power system even under contingency and different loading conditions.

Robust Second Order Sliding Mode Control for A Quadrotor Considering Motor Dynamics

Robust Second Order Sliding Mode Control for A Quadrotor Considering Motor Dynamics

First Order Sliding Mode and Super-twisting Sliding Mode Control of Doubly Fed Induction Generator Driven by Wind Turbine System: A Comparative Study

First Order Sliding Mode and Super-twisting Sliding Mode Control of Doubly Fed Induction Generator Driven by Wind Turbine System: A Comparative Study