Search results for " Electrical and Electronic Engineering"
showing 10 items of 118 documents
Mixed e-assessment: An application of the studentgenerated question technique
2010
This paper presents the experiment of a mixed summative-formative evaluation in an asynchronous distance higher education context. In the experiment, performed in the distance course of Total Quality Management, Industrial Engineering, University of Guadalajara (Mexico), students are guided to formultate questions on specific topics. Studentgenerated questions are evaluated through an ad-hoc quantitative tool, specifically designed for the purpose: the four-criterion Observation Matrix. The experiment shows: (1) that it is possible to improve the Higher Education evaluation process and formalise students' skill in a more thoroughly way than with traditional evaluation; (2) how the student-e…
Graphical THD minimization procedure for single phase five-level converters
2017
This paper proposes two graphycal procedure to mitigate h harmonics and to minimize the total harmonic distortion (THD), respectively. The paper considers a five-level inverter and fundamental frequency modulation: it computes the two switching angles able to reduce low order harmonics and able to minimize the THD. Simulation results are obtained and, in order to validate the proposed procedure, an experimental prototype is built and experimental results are carried out. The comparison between simulation and experimental results confirms the accuracy of the proposed graphycal procedure. It is shown that the switching angles to mitigate the third-fifth and the third-fifth-seventh harmonics e…
LOFT - A large observatory for x-ray timing
2010
The high time resolution observations of the X-ray sky hold the key to a number of diagnostics of fundamental physics, some of which are unaccessible to other types of investigations, such as those based on imaging and spectroscopy. Revealing strong gravitational field effects, measuring the mass and spin of black holes and the equation of state of ultradense matter are among the goals of such observations. At present prospects for future, non-focused X-ray timing experiments following the exciting age of RXTE/PCA are uncertain. Technological limitations are unavoidably faced in the conception and development of experiments with effective area of several square meters, as needed in order to…
A circularly polarized wideband high gain patch antenna for wireless power transfer
2018
This article deals with a microstrip patch antenna working at 868 MHz, suitable for the radio frequency wireless power transfer and energy harvesting applications. The proposed monolithic antenna is compact, lightweight and it is printed on a thick substrate in order to maximize the total gain in the broadside direction. The antenna radiates at 868 MHz with a fractional impedance bandwidth of 5% and it shows a gain of 4.14 dB.
Output-feedback-based H∞ control for vehicle suspension systems with control delay
2014
This paper deals with the problem of output-feedback H∞ control for a class of active quarter-car suspension systems with control delay. The dynamic system of the suspension systems is first formed in terms of the control objectives, i.e., ride comfort, road holding, suspension deflection, and maximum actuator control force. Then, the objective is to the design of the dynamic output-feedback H∞ controller in order to ensure asymptotic stability of the closed-loop system with H∞ disturbance attenuation level and the output constraints. Furthermore, using Lyapunov theory and linear matrix inequality (LMI) approach, the existence of admissible controllers is formulated in terms of LMIs. With t…
Local Capacity $H_{\infty}$ Control for Production Networks of Autonomous Work Systems With Time-Varying Delays
2010
This paper considers the problem of local capacity H∞ control for a class of production networks of autonomous work systems with time-varying delays in the capacity changes. The system under consideration is modeled in a discrete-time singular form. Attention is focused on the design of a controller gain for the local capacity adjustments which maintains the work-in-progress (WIP) in each work system in the vicinity of planned levels and guarantees the asymptotic stability of the system and reduces the effect of the disturbance input on the controlled output to a prescribed level. In terms of a matrix inequality, a sufficient condition for the solvability of this problem is presented using …
Robust control of continuous-time systems with state-dependent uncertainties and its application to electronic circuits
2014
In this paper, the problems of robust stability and stabilization are investigated for a class of continuous-time uncertain systems. The uncertainties in the model are state-dependent and belong to a polytopic convex set, as can be found in many electronic circuits and some other applications. The global asymptotic stability conditions for such systems are first established by the classic common quadratic Lyapunov function approach. To reduce conservativeness, a particular class of nonquadratic parameter-dependent Lyapunov functions is introduced, by which improved robust stability conditions for the underlying systems are also derived. Based on the stability criteria, a static output feedb…
Adaptive Neural Stabilizing Controller for a Class of Mismatched Uncertain Nonlinear Systems by State and Output Feedback
2015
In this paper, first, an adaptive neural network (NN) state-feedback controller for a class of nonlinear systems with mismatched uncertainties is proposed. By using a radial basis function NN (RBFNN), a bound of unknown nonlinear functions is approximated so that no information about the upper bound of mismatched uncertainties is required. Then, an observer-based adaptive controller based on RBFNN is designed to stabilize uncertain nonlinear systems with immeasurable states. The state-feedback and observer-based controllers are based on Lyapunov and strictly positive real-Lyapunov stability theory, respectively, and it is shown that the asymptotic convergence of the closed-loop system to ze…
Design on fuzzy control for a class of stochastic nonlinear systems
2014
The problem of Hankel-norm output feedback control is solved for a class of T-S fuzzy stochastic systems. The dynamic output feedback controller design technique is proposed by employing fuzzy-basis-dependent Lyapunov function approach and the conversion on the Hankel-norm controller parameters. Sufficient conditions are established to design the controllers such that the resulting closed-loop system is stochastically stable and satisfies a prescribed performance. The desired output feedback controller can be obtained by solving a convex optimization problem, which can be efficiently solved by standard numerical algorithms Refereed/Peer-reviewed
Impulsive control on the synchronization for a class of chaotic Systems
2014
In this paper, the impulsive control problem on the synchronization for a class of chaotic systems is discussed. Based on Lyapunov stability theory, the new impulsive synchronization strategy is presented to realize the chaos synchronization and possesses the wider scope of application. Finally the numerical simulation examples are given to demonstrate the effectiveness of our theoretical results.