Numerical Approach to Construction of Lyapunov Function for Nonlinear Stability Analysis

Abstract: This study proposes a numerical approach using Adaptive Tabu search (ATS) to construct Lyapunov function that maximizes region of attraction. The proposed methods is directly useful for stability analysis of nonlinear dynamical systems. Two illustrative examples including a synchronous generator possessing multiple equilibriums and a non-autonomous system are given to demonstrate the practicality and effectiveness of the approach

Real-time fuzzy pid-controller for motor speed regulation

ผลงานวิชาการคณาจารย์มหาวิทยาลัยเทคโนโลยีสุรนาร

Optimization of power transfer in a solar energy system

ผลงานวิชาการคณาจารย์มหาวิทยาลัยเทคโนโลยีสุรนาร

Stabilization of an inverted pendulum system via an SIRM neuro-fuzzy controller

This article presents a new neuro-fuzzy controller to stabilize an inverted pendulum system. The proposed controller consists of the Single Input Rule Modules (SIRMs), the artificial neural network (ANN) and the dynamic importance degrees (DIDs). It simultaneously controls both the angle of the pendulum and the position of the cart. The learning of the ANN results in the DIDs. The proposed controller has a simple structure that can decrease the number of fuzzy rules. The simulation results show that the proposed neurofuzzy controller has an ability to stabilize a wide range of the inverted pendulum system within a short periodof time. Moreover, the comparisons of the simulation results between the proposed neuro-fuzzy controller and the SIRMs fuzzy controller are revealed in this article

Harmonic Identification by DQ Axis with Fourier Method for Active Power Filters

This paper proposes a new method of harmonic identification named DQ axis with Fourier (DQF) method. It lies on the basis of the DQ axis method enhanced by the sliding window Fourier analysis (SWFA). The SWFA component and the zero-sequence current considered inside the DQF method account for its excellent results on harmonic elimination, and phase balancing. Lack of phase balancing capability has been a major drawback of the DQ axis, and the SWFA methods used in conjunction with an active power filter. Our computing results based on measured current waveforms of three-phase four-wire systems confirm this

Numerical approach to loss minimization in an induction motor

This paper describes a numerical approach to power-loss minimization in a fractional hp induction motor driven by a voltage-source inverter. The motor parameters are obtained from a genetic algorithm search. Optimum voltage and frequency excitations are arranged as a table for an energy-saving controller. The proposed method is useful under variable-torque load conditions. Simulation and experimental results are presented.Loss minimization Induction motor

STABILITY AND STABILIZATION OF NONLINEAR DYNAMICAL SYSTEMS

Exponential and asymptotic stability for a class of nonlinear dynamical systems with uncertainties is investigated.  Based on the stability of the nominal system, a class of bounded continuous feedback controllers is constructed.  By such a class of controllers, the results guarantee exponential and asymptotic stability of uncertain nonlinear dynamical system.  A numerical example is also given to demonstrate the use of the main result

STABILITY AND STABILIZATION OF NONLINEAR DYNAMICAL SYSTEMS

Exponential and asymptotic stability for a class of nonlinear dynamical systems with uncertainties is investigated.  Based on the stability of the nominal system, a class of bounded continuous feedback controllers is constructed.  By such a class of controllers, the results guarantee exponential and asymptotic stability of uncertain nonlinear dynamical system.  A numerical example is also given to demonstrate the use of the main result

Dynamic coast control of train movement with genetic algorithm

The railway service is now the major transportation means in most of the countries around the world. With the increasing population and expanding commercial and industrial activities, a high quality of railway service is the most desirable. Train service usually varies with the population activities throughout a day and train coordination and service regulation are then expected to meet the daily passengers' demand. Dwell time control at stations and fixed coasting point in an inter-station run are the current practices to regulate train service in most metro railway systems. However, a flexible and efficient train control and operation is not always possible. To minimize energy consumption of train operation and make certain compromises on the train schedule, coast control is an economical approach to balance run-time and energy consumption in railway operation if time is not an important issue, particularly at off-peak hours. The capability to identify the starting point for coasting according to the current traffic conditions provides the necessary flexibility for train operation. This paper presents an application of genetic algorithms (GA) to search for the appropriate coasting point(s) and investigates the possible improvement on fitness of genes. Single and multiple coasting point control with simple GA are developed to attain the solutions and their corresponding train movement is examined. Further, a hierarchical genetic algorithm (HGA) is introduced here to identify the number of coasting points required according to the traffic conditions, and Minimum-Allele-Reserve-Keeper (MARK) is adopted as a genetic operator to achieve fitter solutions