FERKOVÁ, Ž., ZBORAY, L.:
Robust Control Design of a DC Drive [full paper]
Pole region assignment method ensures sufficient damping for systems with varying poles within the defined interval. It connects analytical and graphical approach for selection of two controller parameters. The same result may be reached by the introduced numerical procedure for a third order control loop. Robust speed controller of a DC drive is designed and analysed. Results are illustrated by time responses obtained by simulation.

ČOPJAN, Ľ., KRAHULEC, J., MARCHEVSKÝ, S., BENČO, S.:
3State Channel Model for Land Mobile Satellite Communications [full paper]
For moving obstacles, such as people or cars, strength of the received signal is variable through the time. These variations are caused by the environment. In this paper, 3state channel model for land mobile satellite communications, based on a Rice and extended Suzuki distribution of type I. is proposed. Numerical and graphical outputs in the System View environment are presented to show how the channel works.

MACEKOVÁ, Ľ., GALAJDA, P.:
High Altitude Platforms for Communications and Other Wireless Services [full paper]
High Altitude Platforms (HAPs) are quasistationary vehicles in stratosphere, i.e. between the operational space of the terrestrial and satellite communications equipments. The solarpowered airplanes, airships or balloons can serve in the role of HAPs. The HAPs and their applications offer potential benefits for the delivery of communications services, internet multimedia, remote sensing and navigation system support. The applications of HAPs have the best properties from both terrestrial and satellite broadcasting, such as a small delay and undisturbed lineofsight link between the customer and base station. They have been the subject of civil and military interest and of international projects for the past few years. In the following article the overview of the main aspects and some results of successive trials of this promising technology will be described.

BOKR, J., JÁNEŠ, V., JÁNEŠOVÁ, M.:
Dynamic System [full paper]
The paper deals with a quite new conception of logic control. The
conception model of the program CA (Control Automaton) will be set up on
CA with a failure input, whereas a feedback CA can do without a failure
input. CA is a static system, i.e. it is a minimal one, with respect to
the number of states.

KADDOUREL BOUDADI, L., BERRACHED, N.:
Multi Users Internet Based Teleoperation Station with Augmented Reality [full paper]
This paper describes a robot arm teleoperation station with visual and sensory feedback. This is a model based station using a 3D graphic interface that allow an operator to plan and control the robot movements with a mouse using visual and sensory information received back from the workspace through Internet. The interactions between the operator and the virtual world through the I/O data provide an immersion sensation and an update of the virtual environment by the real (position) sensory feedbacks. This works shows that it is possible with this station to execute and to supervise in near real time a robot arm.

CHENAFA, M., MEROUFEL, A., MANSOURI, A., MASSOUM, A.:
Fuzzy Logic Control of Induction Motor with Input Output Feedback Linearization [full paper]
The proposed system combines the inputoutput linearization technique and the advantages of fuzzy logic control (intuitiveness, simplicity, easy implementation and minimal knowledge of system dynamics) to obtain a robust, fast and precise control of induction motor speed. The inputoutput linearizing controller decouples the flux control from the speed control and makes the synthesis of linear controllers possible. However, in practice, parameter variations limit the evolution of the machine flux and the rotor speed. So, a speed fuzzy logic controller for induction motor via feedback linearization with inputoutput decoupling is presented here in order to achieve better tracking performances. The signal rotor flux is estimated with a nonlinear observer and controlled by classical regulator. Simulation results show the importance of the inclusion of fuzzy logic in designing inputoutput linearizing control laws. Similarly, it validates the robustness and effectiveness of the proposed fuzzy logic controller for high performance of inputoutput linearized induction motor drive.

DJAHBAR, A., MAZARI, B.:
High Performance Motor Drive Using Matrix Converter [full paper]
The presented paper deals with the designed concept of the matrix converter control system employed in the industry applications. Matrix converters provide an allsilicon solution to the problem of converting AC power from one frequency to another, offering almost all the features required of an ideal static frequency changer.They possess many advantages compared to the conventional voltage or current source inverters. A matrix converter does not require energy storage components as a bulky capacitor or an inductance in the DClink. It enables the bidirectional power flow between the power supply and load. The most of the contemporary modulation strategies are able to provide practically sinusoidal waveforms of the input and output currents with negligible low order harmonics and to control the input displacement factor. The solution is advantageous especially with regard to the above mentioned reactive component reduction.
A new direct AC/AC converter topology based on the scalar modulation strategy with three intervals and vector control technique for matrix converter fed induction motor drive system is proposed. It is shown, through analysis and simulation, that the proposed matrix converter topology is free of any switching difficulties and gives high quality sinusoidal waveformson both sides. The primary objective of this research effort is to evaluate the utility of the matrix converter in industry applications, primarily for motor control.Closedloop direct and indirect vector control has been presented and simulated using a 1.5 Kw induction motor. By applying this control strategy, we will be able to combine the advantages of matrix converter and the advantages of the vector control. Simulation results are shown to demonstrate the effectiveness of the proposed control scheme.

ALLALI, A., BOUZEBOUDJA, H., MOHAMED, L., RAHLI, M., ZEBLAH, A.:
Optimal Distribution of Active Powers Using Linear Programming with Losses Cost Minimization [full paper]
This paper deals with application of linear programming techniques to achieve a mixed economic distribution of the active powers (production cost of active power and cost of the losses of transmissions) in an electric power. Performance indexes related to energy production are nonlinear. Newton method is used for linearising these cost functions around an operating point prior to their minimisation. In the first, the problem is solved by considering the fuel performance indexes only while maintaining transmission losses constant. In the second, we have considered transmission losses and production costs at the same time. We will also consider that the active losses are a function of the generated active powers and hence the coefficient of this function may be calculated with the Generalised Generation Factors Distribution (GGFD) method.

BENDIABDELLAH, A., BENOUZZA, N., TOUMI, D.:
Cage Motor Faults Detection Algorithm Using Speed Estimation and Current Analysis [full paper]
The study of the Power
flow is very significant, because it makes it possible to provide
information of large importance; in order to better plan, to control and
ensure finally the correct operation of the electrical supply networks.
In our article, we present a method of calculation of the flow of powers
in a mixed electrical supply network in high voltage (AC/DC). This
method called also method SPI: (Substituted Power Injection) makes a
small modification to the level of the bus of connection DC. The
calculation of the active and reactive powers at the final bus of system
ACDC, are obtained by the subtraction of the powers of the converters
and those which are specified with the bus of connection DC. This method
will be applied to the 14 bus networks.

ALEKSIĆ, S. R., ILIĆ, S. S.:
Determination of Critical Atmospheric Electric Field around Franklin's Lightning Protection Rod that Leads to BreakDown [full paper]
In this paper atmospheric electric field distribution is determined in
the vicinity of the Franklin’s lightning protection rod top which is
modeled by halfspherical ending. Special emphasis is given to
determination of critical atmospheric electric field that leads to
breakdown at the top of the rod. For the values of external atmospheric
electric field that overcome critical value at the rod top, the corona
occurs, so linear analysis is not valid any more. In this paper the
first Laplace equation for potential is solved, for Franklin lightning
protection rod approximated with one half of the prolate rotational
ellipsoid in homogeneous earth atmospheric electric field, and the
equation itself is solved in the coordinate system of prolate rotational
ellipsoid. For that case, electric field along zaxis is determined and
especially at the top of the rod. As numericalmethods, method of
subsections and finite element method are used and the comparison of
these two methods is given.

MILIVOJEVIĆ, D. R., TASIĆ, V.:
Some Software Elements of the Microprocessor Measuring Station [full paper]
Last couple of years the Department of Industrial informatics has been developing industrial control systems. As a result, a distributed control system (DCS) has been developed. The practical applications of the system in industrial plants, especially in power consumption control and copper metallurgy production processes, confirms designed system performances in real environment. The kernel of control systems is the microprocessor measuring station  MMS. In hardware and software point of view MMS is a type of PLC (Programmable Logic Controller) with some of local and remote functional possibilities. The MMS hardware configuration is adapted for actual process control requirements with adequate number of input channels and adequate response time. It is mainly dedicated as an interactive node of industrial LAN. If it is necessary, MMS can operate autonomous, doing measuring and collecting the results, as a data logger. That is a MMU (Mobile Measuring Unit) version. The paper describes the software structure of the executive system and its main functions. The details of communications software and local operation control program are out of scope of this article.

