Synchronous Control Technique Research Articles

A time-efficient nonlinear control method for the hyperchaotic finance system synchronization

Irregular and complex behavior in the financial system can disrupt stability and smooth economic growth. It causes randomness within the system, generating chaos; hindering synchronization behaviour. Achieving smooth and rapid synchronization between two coupled hyperchaotic finance (HF) systems with lessened fluctuation of input and output signals is vital for continuing financial stability and fostering economic growth, a challenge addressed in this article. The paper proposes a novel time-efficient nonlinear control (TENLC) technique and investigates HF systems synchronization using the drive-response system (DRS) arrangement. The proposed TENLC strategy realizes fast and smooth synchronization behaviour between two coupled HF systems, reducing closed-loop state-variable trajectory oscillations. The controller is designed to retain the nonlinear components within the closed-loop system and does not depend on the system's parameters, simplifying the design and analysis process. The Lyapunov stability technique confirms the closed-loop's global stability at the origin. Proofs of mathematical analysis and computer-based simulation results validate the theoretical findings, showing that the presented TENLC strategy converges the state error trajectories to zero in a short transient time with lessened fluctuations for all signals. The comparative computer-based simulation analysis confirms that the presented TENLC approach outperforms other synchronization control techniques.

Synchronization of chaotic satellite systems with an unknown parameter

Spacecraft (satellite) formation has several applications in space exploration. Synchronization controllers are essential in satellite formation systems. This article proposes a novel robust adaptive synchronization control (RASC) technique for two identical three-dimensional chaotic satellite systems attitude synchronization with an unknown system parameter, unknown bounded model uncertainties, unknown external disturbances, and nonlinear terms. This controller achieves smooth error vector convergence to zero. The closed-loop has a robust performance as the controller avoids plant nonlinear terms cancellation. This controller has two parts. (i) A nonlinear controller for keeping the closed-loop stable; it flourishes robust and faster error vector convergence to zero with reduced fluctuations. (ii) An adaptive nonlinear controller that compensates exogenous disturbances and model uncertainties using online estimations of model uncertainties and bounds. The Lyapunov stability theory assures the closed-loop's global asymptotic robust stability. Computer simulation results-based analysis verifies the theoretical findings. The article includes a comparative study and discusses the control effort saturation effects.

Synchronization control techniques for shunt active power filter: an overview

The phase synchronization control technique of shunt active power filter (SAPF) is discussed in this article. Due to the harmful effects of harmonic currents on power systems, the issue of decreasing their effects has generated a lot of research. A SAPF is acknowledged as the most dependable instrument in this area. The SAPF will detects the current harmonics present in the power system and also generates and injects the corrective current mitigation in the power system to reduce the current harmonics. This implies that, aside from the capacity to create compensating current, it is more essential to ensure that the SAPF can work in phase with the operational power system so that the compensating current will properly injected. As a result, while constructing SAPF control algorithms, correct synchronisation techniques must be incorporated. In this article, the different types of phase synchronization approach have been discussed such as phase-locked loop (PLL), adaptive linear neuron (Adaline), and unit vector. The results of the study may be used as a guideline and source of information for determining the best method for synchronising SAPF with the associated power system.

Distributed leaderless formation control for multiple autonomous underwater vehicles based on adaptive nonsingular terminal sliding mode

In this study, we address the formation control problem of multiple autonomous underwater vehicles (AUVs) in the presence of model uncertainties and ocean-current disturbances. Specifically, we propose a robust distributed leaderless formation control strategy by cross-coupling a synchronous control technique, a nonsingular terminal sliding-mode control approach, and an adaptive control method. We enhance the robustness against system uncertainties by redefining the cross-coupling errors and ensure that the finite-time tracking error converges to zero from any initial value via the designed adaptive nonsingular terminal sliding mode control, which also eliminates the chattering problem. A major advantage of our adaptive control law is neglecting the requirement of any prior knowledge about the upper bounds of the model uncertainties and ocean-current disturbances. Our comparative simulation results demonstrate the effectiveness of the proposed distributed leaderless formation control scheme.

Robust Adaptive Multi-Switching Synchronization of Multiple Different Orders Unknown Chaotic Systems

Multi-switching synchronization (MSS) of multiple different orders unknown chaotic (UC) systems confines hacking in the digital transmission process. Similarly, the suppression of undesirable chattering increases synchronization performance. This paper proposes a new robust synchronization control (RASC) technique and discusses the MSS of multiple different orders UC systems. This controller accomplishes (i) quick convergence, (ii) reduces the transient oscillations, and (iii) the rate of convergence decreases in the vicinity of the origin that causes the suppression of chattering. Analysis based on the Lyapunov direct method assures this convergence behavior with any positive values of the feedback gains. This work also provides parameters updated law that estimates the true values of unknown parameters. Numerical examples of five UC systems different orders are simulated. The computer based graphical results validate the efficiency and performance of the proposed RASC technique and the synchronization strategy when compare to peer works. In the simulation, the proposed synchronization strategy successfully recovers an encrypted received image on a communication channel. The article suggests some future research problems to extend the use of the proposed work.

An advanced virtual synchronous generator control technique for frequency regulation of grid-connected PV system

The future power system is developing to an inverter-based system from a machine dominated power system due to a large integration of renewable energy sources (RESs). Lack of inertial part and intermittency of the RESs causes frequency instability in the power system. The virtual synchronous generator (VSG) development has been made to add inertial control to the power system for controlling the frequency deviation caused by the integration of the photovoltaic system. The VSG system comprised of power electronics components having a droop control mechanism like the conventional synchronous generator, which provides the necessary frequency stability to the power system. In this paper, three parallel VSG based photovoltaic systems integrated with battery storage systems are used to analyze the frequency response and its stability. Moreover, an advanced genetic algorithm optimization method is used to get the optimal values of parameters of the droop controller used in VSG. Furthermore, two different cases with respect to variation in supply and load power of the system are analyzed in detail. Additionally, an IEEE 14 bus system is utilized to validate the proposed system in MATLAB/Simulink. Evident improvements are observed in the simulation results presented through the suggested GA based VSG control technique.

Synchronization of Non-Integer Complex Chaotic Systems with Uncertainty and Disturbances via Adaptive Sliding Mode Technique

In this paper we concern the adaptive sliding mode control technique for synchronization of fractional order chaotic systems with uncertainties and disturbances. This technique is used to design control law through suitable sliding surface and estimate the external disturbances. Computational results using MATLAB verified the effectiveness of the proposed scheme.

Modelling of distributed generation system based on virtual synchronous generator control technique

Modelling of distributed generation system based on virtual synchronous generator control technique

Modelling of distributed generation system based on virtual synchronous generator control technique

Virtual synchronous generator (VSG) control method is considered as a suitable solution for controlling distributed generation (DG) system-based inverter, due to its ability to improve the microgrid stability. The VSG control method consists in controlling the power electronic interface-based DG unit to mimic the main dynamic of the conventional synchronous generator. Unlike, conventional synchronous generators, the load angle is not enough small in case of low and medium DG systems, moreover, they are usually connected to the grid through low and medium voltage lines, where the line impedance is not purely inductive, result in a strong coupling between active and reactive powers as well as nonlinearity between active and reactive powers functions and controls variables. This paper proposes a linear model of DG system with VSG controller based on a small signal analysis. The developed model has been investigated and compared with the detailed simulation model of a studied microgrid.

A Synchronization Control Technique For Soft Connection of Doubly Fed Induction Generator Based Wind Turbines to the Power Grids

Doubly-fed induction generator (DFIG)-based wind turbine generators need to be connected back to integrated power grid after tripping due to disturbances and emergencies in power grid. Re-connection can cause switching transients which may affect overall grid stability. This situation can be avoided if proper synchronization can be ensured for smooth transition of DFIG from island mode to grid-connected mode. To this effect, in this paper, a direct voltage control based synchronization method is introduced that can ensure low or no transient effect during synchronization of DFIG to the grid. The controller is synthesized based on a multi-channel identification methodology and integrated using a designed grid connection logic for soft synchronization. The architecture is implemented on a modified IEEE 39 bus system with DFIG and tested on a real-time simulation platform with different wind speed conditions. It is observed that the proposed architecture makes the grid more stable (with swings in voltage or frequency reduced as much as 60%) during re-connection of wind generators.

Control Technique for Synchronization of Selected Nodes in Directed Networks

In this letter, we propose a method to control a set of arbitrary nodes in a directed network such that they follow a synchronous trajectory which is, in general, not shared by the other units of the network. The problem is inspired to those natural or artificial networks whose proper operating conditions are associated to the presence of clusters of synchronous nodes. Our proposed method is based on the introduction of distributed controllers that modify the topology of the connections in order to generate outer symmetries in the nodes to be controlled. An optimization problem for the selection of the controllers, which includes as a special case the minimization of the number of the links added or removed, is also formulated and an algorithm for its solution is introduced.

Synchronous Resonant Control Technique to Address Power Grid Instability Problems Due to High Renewables Penetration

This paper presents a synchronous resonant control strategy based on the inherent characteristics of permanent magnet synchronous generators (PMSG) for the control of power converters to provide stable operating conditions for the power grid under high penetration of renewable energy resources (RERs). The proposed control technique is based on the small signal linearization of a dynamic model with grid specifications, load-current-based voltages, and power converter currents. A combination of the linearized dynamic model with the PMSG swing equation and resonant controller leads to a control technique with synchronous features and appropriate inertia for the control of converter-based power generators. As the main contribution of this work, an extra functionality is proposed in the control loop of the proposed model to solve the inherent inconveniences of conventional synchronous generators. Also, a comprehensive collaboration between interfaced converter specifications and PMSG features is achieved as another contribution of the proposed control technique, and this can guarantee accurate performance under various conditions. A current perturbation curve is introduced to assess the variations of the grid frequency and voltage magnitude under operation of the interfaced converters controlled by the proposed control technique. Moreover, by taking into account the load-based voltages, the effects of the current perturbation components are investigated. The proposed model is simulated in MATLAB/Simulink environment to verify the high performance of the proposed control technique over the other existing control methods.

Integration of Photovoltaic Energy to the Grid, Using the Virtual Synchronous Generator Control Technique

Integration of Photovoltaic Energy to the Grid, Using the Virtual Synchronous Generator Control Technique

Controller design scheme for stabilization and synchronization of a class of chaotic and hyperchaotic systems in uncertain environment using SMC approach

This paper presents sliding mode control (SMC) technique for stabilization and synchronization of a class of chaotic/hyperchaotic systems in master–slave configuration. Here, a detailed procedure for deriving a single controller using SMC technique based proportional-integral sliding surface is proposed. Adaptation laws have been derived for the system parameters when the systems are subject to parametric uncertainties. Further, explicit criteria to decide the minimum number of control inputs required to meet out the desired operation of stabilization and synchronization is also proposed. Lyapunov stability theory is utilized to accomplish the desired objective. The proposed controller ensures the occurrence of sliding motion and achieves synchronization for the addressed class of chaotic/hyperchaotic systems in master–slave configuration. To validate the analytical results, example of four dimensional Lorenz–Stenflo hyperchaotic system is considered. Finally, detailed simulation results are provided to illustrate the effectiveness of the proposed controller.

An Adaptive Control Technique for Motion Synchronization by On-line Estimation of a Recursive Least Square Method

This article presents an adaptive technique to tune controller gains for the motion synchronization of two gimbal systems by using a recursive least square method in the real-time fashion. In the master-slave configuration, the slave gimbal system follows the master’s motion while the master tracks the reference. In order for the slave gimbal system to synchronize with the motion of the master gimbal system, the dynamic difference between two systems is compensated by the controller gains. The controller gains of the slave are adaptively adjusted by the recursive least square method to cope with the deviation. The performances of three control schemes such as an independent PD control, a dependent torque control, and an RLS torque control scheme are evaluated by the experimental studies for the low cost gimbal systems. Experimental studies confirm that the RLS-based adaptive scheme actually outperforms by adjusting controller gains for the motion synchronization of the master and slave configuration.

Exponential synchronization of memristive neural networks with time delays

Abstract It is known that the parameters of memristive neural networks (MNNs) are state-dependent, and the unexpected parameter mismatch issue between driven system and response system might be caused by the special characteristics of MNNs, then the traditional state feedback synchronization control and analytical techniques cannot be applied directly. In order to solve this problem, one type of new sandwich control structure, which includes two types of sub-controllers and the different control gains, is designed to ensure the exponential synchronization of two MNNs. Meanwhile, in the process of synchronization, the time delays in MNNs and the time delays between drive system and response system in real environment are also considered by us. Based on the concept of Filippov solution, Lyapunov stability theory, matrix inequality, etc., the exponential synchronization conditions for the MNNs with two types of time delays via sandwich control are given. Finally, a numerical example is displayed to show the efficiency and feasibility of this method.

Distributed Noise-Resilient Networked Synchrony of Active Distribution Systems

This paper proposes a distributed noise resilient control technique for voltage and frequency synchronization in inverter-based ac microgrids. Existing cooperative control techniques assume ideal communication among inverters. The effect of additive noise in communication links among inverters, and between the reference signal and inverters, on the synchronization process, is studied. Distributed least mean-square solutions estimate the reference set points, and a local least mean-square algorithm estimates neighboring inverter frequencies and voltages. The efficacy of the proposed solution, for an islanded microgrid test system under the additive noise in reference communication links and links connecting neighboring inverters, is evaluated for a modified IEEE 34-bus feeder system. An upper bound for the noise-induced deviation in the consensus parameter is analytically derived and verified by the simulated testbed.

Control and synchronization of the generalized Lorenz system with mismatched uncertainties using backstepping technique and time‐delay estimation

SummaryWe propose a robust control technique for regulation and synchronization of the generalized Lorenz system (GLS) that covers the Lorenz system, Chen system and Lü system. The proposed control provides synergy through the combination of the backstepping control and time‐delay estimation (TDE) technique. TDE is used to estimate and cancel nonlinearities and uncertainties while the backstepping method is adopted to provide robustness against matched and mismatched uncertainties. As a result, we observe in numerical simulation that the proposed technique shows better performances in regulating and synchronizing the GLS with mismatched uncertainties, in comparison with existing schemes. The efficacy of the proposed technique is also validated with a circuit‐implemented chaotic system. Copyright © 2017 John Wiley & Sons, Ltd.

Controller Parameter Optimization for the Robust Synchronization of Chaotic Systems with Known and Unknown Parameters

In this paper, a synchronization problem of a three-dimensional (3-D) Coullete chaotic system using the active- and adaptive-based synchronization control techniques is addressed. Based on the Routh-Hurwitz criterion and using the active control algorithm, a single control function is considered and a computational study is performed to identify the correct balance between the converging rates of the synchronization error signals to the origin and magnitude of the linear controlling parameters (LCPs) for the globally exponential synchronization (GES) between two identical 3-D Coullete chaotic systems. In order to achieve the complete synchronization (CS) objective with unknown model uncertainties, external disturbances, and unknown time-varying parameters, a novel nonlinear adaptive synchronous controller is proposed and suitable adaptive laws of time-varying parameters are designed that accomplish the asymptotic synchronization between two identical uncertain 3-D Coullete chaotic systems. The two synchronizing controlling approaches are applied to investigate the CS phenomenon, and the results are compared. Open research problems are also discussed. All simulations results are carried out to validate the effectiveness of the proposed synchronization control approaches by using Mathematica 10.0.

Experimental Investigation on Limit Cycle Wing Rock Effect on Wing Body Configuration Induced by Forebody Vortices

The purpose of this paper is to present the aerodynamic and flow characteristics of a slender body with a 30° swept wing configuration undergoing a limit cycle oscillation using a synchronous measurement and control technique of wing rock/particle image velocimetry/dynamic pressure associated with the time history of the wing rock motion. The experimental investigation was concentrated on 3 main areas: motion characteristics, static and dynamic surface pressures and static and dynamic particle image velocimetry. The tests’ results revealed that the lag in asymmetric twin vortices over the forebody switching from the left vortice pattern to the right one exhibits a hysteresis evolvement during the wing rock motion; the asymmetric triple vortices over the forebody interacted with the flowfield over wings appeared to induce the instability and damping moments. The main flow phenomena responsible for wing rock of wing body configuration were completely determined by the forebody vortices. These exhibit apparent dynamic hysteresis in vertical position, which further influences the wing flows, and the dynamic hysteresis of flows yields the damping moments sustaining the oscillations.