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International Review of Electrical Engineering - February 2008 - Papers

On the Study of Modernized Lightning Air Terminal
Dynamic Single-Phase DVR System with Instantaneous Power Factor Estimator
Overvoltage Protection Optimization of Medium Voltage Network
Electrostatic Shaft Voltage at the Crack – Gas Compressor: the Phenomenon Analyses, Testing, Measuring and the Problem Solution
A New Artificial Neural Network Approach With Selected Inputs for Short Term Electric Load Forecasting
A New Method for Evaluation of Distribution System Losses Due to Load Unbalance
Multiobjective Genetic Algorithms for Online Management Problem of Microgrid
Application of Numerical Distance Relays in Dispersed Generation
A New Control Method of Hybrid Active Filter to Eliminate the 5th and 7th Harmonic Frequency Using Self-Tuning-Filter in the Feedforward Loop
Design Aspects of the Series Active Power Filter
Modeling and Adaptive Control of Two-Stage Matrix Converters
A New Design for Analogue Maximum Power Point Tracking
Step by Step Design of the Power Stage of a Light Electric Vehicle
Analytic Design of a Permanent Magnet Synchronous Motor Dedicated to EV Traction with a Wide Range of Speed Operation
Methods of Modeling and Identifying the Electrical Characteristics of Super Capacitor Energy Storages
Analysis of a Cylindrical Passive Suspension System Using Finite Element Method
The Soft-Starters Modeling, Simulations and Control Implementation for 2 MW Constant-Speed Wind Turbines
Dynamic Modeling, Simulation and Control of the Power Conditioning System for a Variable-Speed Wind-Turbine
Fractional Order Speed Observer for Sensorless Induction Motor Drives
Induction Motors Bearing Failures Detection and Diagnosis Using a RBF ANN Park Pattern Based Method
Design of a New Sensorless Controller of Induction Motor Using Backstepping Approach
The Finite Element Method In Shielding Problems
Combining the Moments Method and the PEEC Method With the Kron’s Transformation for Studying Embedded Systems EMC
A Dual-Function RF Filter for 5GHz WLAN and UWB with Narrowband Interference Rejection
On the Study of Modernized Lightning Air Terminal
The Contribution of Vehicle Headlights to Visibility of Targets in Road Lighting Environments

International Review of Electrical Engineering - Papers

On the Study of Modernized Lightning Air Terminal
by M. A. B. Sidik, H. Ahmad

Vol. 3. n. 1, pp. 1-8

Abstract - In a direct strike lightning protection system, three components are considered to be of great significance; that is lightning air terminal (LAT), down-conductor (DC), and earth terminal (ET). Since the time of Benjamin Franklin, the founder of lightning rod, until today there are many types of LAT that have been installed on building structures around the world to provide protection to the human being and equipment from the effect of lightning strokes. In general LAT could be classified as in compliance with standard and non-standard method. However, generally people at large are unable to differentiate between standard and non-standard method of protection involving the use of LAT. The latter performance and its scientific explanation provided by vendors have created controversies among lightning scientists and practicing engineers. The development and research on technologies to control or even to prevent lightning strokes continues till today. This paper describes a current research going on related to the subject concern and possible technologies which can be used for future generation of LAT.

Keywords: Power factor determination, dynamic voltage restorer, virtual two-phase system, instantaneous reactive power theory, moving average method.

Dynamic Single-Phase DVR System with Instantaneous Power Factor Estimator
by B. Dobrucky, P. Spanik, M. Pokorny

Vol. 3. n. 1, pp. 9-16

Abstract - The paper deals with the high dynamic properties of single-phase dynamic voltage restorer (DVR) using instantaneous power factor determination. Knowledge of power factor determination is necessary for using of minimum energy control method for good DVR control. Especially for single-phase DVR the virtual approach is used, when ordinary single-phase quantity is to complete by virtual fictitious phase, so that both of them will create orthogonal two-phase system, as in three-phase systems. It is very similar to that of approach used in [14] for control of single-phase active power filter providing very good dynamical properties. Practical application of instantaneous active, reactive power and power factor determination method uses moving average technique. The paper shows some examples of the simulation results, which proved fast dynamic response of single-phase DVR.

Keywords: Power factor determination, dynamic voltage restorer, virtual two-phase system, instantaneous reactive power theory, moving average method.

Overvoltage Protection Optimization of Medium Voltage Network

by M. Marttila, P. Verho, K. Kannus

Vol. 3. n. 1, pp. 17-22

Abstract - Traditionally distribution networks have been protected against lightning to prevent failures of expensive network components, but now there are also other challenges for overvoltage protection. Short interruptions and voltage dips are now an object of great attention, because the importance of power quality has increased. In the future power quality will have an influence on network companies’ profits due to regulator of Finland. Overvoltage protection planning is therefore a challenging task. With efficient lightning protection short interruptions and voltage dips could be substantially reduced. With an advanced reliability analysis tool integrated into the network information system, the effect of different overvoltage protection strategies can be studied. Fault modeling and reliability analysis with economic analysis also make this tool efficient in overvoltage protection optimization. The calculations presented in this paper show that investments in increased overvoltage protection are extremely profitable if short interruptions and also voltage dips are taken into account as outage costs.

Keywords: Lightning overvoltage, short interruption, voltage dip, overvoltage protection, reliability analysis.

Electrostatic Shaft Voltage at the Crack – Gas Compressor: the Phenomenon Analyses, Testing, Measuring and the Problem Solution

by B. I. Jeftenić, L. B. Ristić

Vol. 3. n. 1, pp. 23-31

Abstract - While measuring vibrations and temperature at proper locations of the crack-gas compressor in the Ethylene Plant of Petrohemija Pančevo, it was observed that some values exceeded their limits, so the advanced tests were completed in order to access the cause of machine damage. Analyses of achieved results lead to a conclusion that the cause of machine damage is dc voltage, always of the same polarity. Therefore, to avoid unplanned expensive failures in the production process, as well as ecological disaster, solutions to overcome this phenomenon are proposed in the paper. Besides the detailed analyses of the electrostatic voltage phenomenon at the machine shaft, the paper presents an overview of damages within a machine which are consequences of this phenomenon. The paper also presents the description of performed investigations, results of measurements and their analyses, which are all the base of suggested methods for the problem solution.

Keywords: shaft currents, dc voltages, bearings, compressor, machine damage.

A New Artificial Neural Network Approach With Selected Inputs for Short Term Electric Load Forecasting

by Z. H. Ashour, M. A.Farahat

Vol. 3. n. 1, pp. 32-36

Abstract - A new improved inputs selection approach for artificial neural networks (ANN) is proposed to model and forecast time series. The procedure makes use of the correlation analysis of the time series data both in selecting the inputs to the ANN and in deciding its structure. The correlation linking the time series to another prime input other than the past observations is taken into consideration. The improved inputs selection approach uses the available knowledge of existing physical models or transfer function model to add new selected inputs to the ANN in order to construct the best model for the time series. The approach is used in modeling and forecasting the load demand for the city of Zagazig in Egypt. The performance is compared with two other neural network models of the load time series fed with different set of inputs to show the superiority of the proposed approach.

Keywords: Time series analysis, artificial neural networks, inputs selection for the artificial neural network, short term load forecasting.

A New Method for Evaluation of Distribution System Losses Due to Load Unbalance
by R. M. Ciric, H. Nouri

Vol. 3. n. 1, pp. 37-45

Abstract - Unbalance and harmonics are two major distortions in the three-phase distribution systems. In this paper new loss coefficients describing correlation between power losses due to unbalance and voltage unbalance in the distribution system, are introduced. The loss coefficients enable fast evaluation of unbalance losses in real life distribution systems by using available voltage data obtained from measurements in the field. For loss analysis a general power flow algorithm for three-phase four-wire radial distribution networks, based on backward-forward technique, is applied. Results obtained from several case studies using medium and low voltage test feeders with unbalanced load, are presented and discussed.

Keywords: Distribution networks, Load unbalance, Current unbalance, Voltage unbalance, Losses .

Multiobjective Genetic Algorithms for Online Management Problem of Microgrid

by F. A. Mohamed, H. N. Koivo

Vol. 3. n. 1, pp. 46-54

Abstract - In this paper a generalized formulation for determining the optimal operating strategy and cost optimization scheme as well as reducing the emissions of a Microgrid (MG) is presented. Multiobjective (MO) optimization is applied to the environmental economic problem of the MG. The MG considered in this paper consists of a wind turbine, a micro turbine, a diesel generator, a photovoltaic array, a fuel cell, and a battery storage. Multiobjective genetic algorithm is used in the optimization which is aimed at minimizing the cost function of the system while constraining it to meet the customer demands and safety of the system. Three typical scenarios of MG operation are investigated. A comparison is made in the last scenario with the conventional optimization technique. The results in the paper demonstrate the efficiency of the proposed approach satisfying the load and to reducing the cost and the emissions in one single run.

Keywords: Microgrid, Multiobjective Optimization, Genetic Algorithms, Load management.

Application of Numerical Distance Relays in Dispersed Generation

by D. Labed, A.Bouzid, M. Zellagui, M. Bouchahdane

Vol. 3. n. 1, pp. 55-64

Abstract - This paper describes the application of numerical distance relays 7SA612 (of family 7SA of Siemens) for dispersed generation connected to HV network, using software DIGSI 4.7 of SIEMENS. DIGSI is a graphical tool to manage components within systems SIEMENS protection. The basic principles of an electromechanical, static and numerical distance relay are also described in this paper. A 220 kV, 100 km transmission line and a 7SA612 type numerical distance relay are selected as examples for fault simulation and relay testing. Some simulation results are given.

Keywords: Dispersed generation, Connection with HV network, Distance protection, Numerical distance relay, SIPROTEC 7SA612.

A New Control Method of Hybrid Active Filter to Eliminate the 5th and 7th Harmonic Frequency Using Self-Tuning-Filter in the Feedforward Loop
by M. Abdusalam, P. Poure, S. Saadate

Vol. 3. n. 1, pp. 65-71

Abstract - In this paper, we proposed a new control method for a three-phase hybrid active filter, based on a classical active filter topology connected in series with a passive filter. The non linear load is a diode rectifier feeding a (R, C) parallel load. The proposed method is based on two Self Tuning Filters placed in both feedback and feedforward loops dedicated to eliminate the 5th and 7th harmonic frequency. The feedforward loop consists in two branches, the first one to remove the 5th harmonic and the second one to remove the 7th harmonic frequency. The use of Self Tuning Filters simplifies the control scheme by reducing the number of extraction filters used in classical feedback and feedforward loops. More, in this case, no Phase Locked Loop is necessary for the feedforward loop. The effectiveness of the new proposed scheme has been verified by computer simulation and the results are compared with the classical control scheme.

Keywords: Active Hybrid Filter, Diode Rectifier, Feedback and Feedforward Control, Harmonics, Self-Tuning Filter (STF).

Design Aspects of the Series Active Power Filter
by J. Turunen, H. Tuusa

Vol. 3. n. 1, pp. 72-82

Abstract - Active power filters have been developed to solve the growing harmonic problem occurring in the power network. Two main topologies of active power filters exist: the parallel active power filter and the series active power filter. In addition, there are also combinations of the active power filters and passive filters, i.e. hybrid active power filters. The parallel active power filter has been more popular both academically and commercially than the series active power filter. However, in this paper the design aspects of the series active power filter as part of the series hybrid active power filter are discussed. The beginning of the paper presents the main circuit and the control system of the investigated series hybrid active power filter. Unlike in conventional series active power filters, the delta connection is used on the primary side of a coupling transformer. Next, the design aspects of the series active power filter are discussed. Finally, the measurement results of experimental tests are presented.

Keywords: Active filter, harmonics, power quality.

Modeling and Adaptive Control of Two-Stage Matrix Converters
by M. Hamouda, F. Fnaiech, K. AL-Haddad

Vol. 3. n. 1, pp. 83-92

Abstract - This paper describes the complete analysis and design of an adaptive nonlinear controller for Two-Stage Matrix Converters. The proposed controller is constructed with the aim to drive the converter at unity input displacement factor operation independently of the output voltage frequency and magnitude. First, a state-space average model of the converter is constructed into two d-q rotating reference frames synchronized with the input and output frequencies respectively. Next, an input-state feedback linearization current controller followed by a MRAC scheme is developed. The adaptation law is derived using the concept of augmented error and Lyapunov stability theory. Finally, the indirect Space Vector Modulation approach is used to generate the overall switching pattern. Numerical simulations are given confirming the effectiveness of the proposed control approach and theoretical development. The following attractive features are recorded:
- The currents drawn by the converter are sinusoidal with low distortion.
- The converter operates at unity input displacement factor over a wide range of the output voltage magnitude and frequency.
- The dynamic behavior of the overall control system is robust with regard to parametric variations.

Keywords: DTC, CSI, induction motor.

A New Design for Analogue Maximum Power Point Tracking
by R. Chenni, L. Zarour, M. Amarouayache, A. Bouzid

Vol. 3. n. 1, pp. 93-99

Abstract - A study of the maximum power point trackers using a switching-frequency modulation scheme (SFMS) for photovoltaic panels is presented; a dc/dc converter is used. Method of locating the maximum power point (MPP) is based on injecting a small-signal sinusoidal perturbation into the switching frequency of the converter and comparing the ac component and the average value of the panel’s terminal voltage. Apart from not requiring sophisticated computation of the panel power, this SFMS does not approximate the panel characteristics and can globally locate the MPP under wide irradiation conditions. Theoretical predictions will be verified with experimental results. Operating characteristics at steady state and in large-signal change of the solar irradiance (incident solar radiation) level will be studied.

Keywords: dc/dc converter, maximum power point tracking (MPPT), photovoltaic systems.

Step by Step Design of the Power Stage of a Light Electric Vehicle
by F. J. Pérez-Pinal, C. Núñez, R. Álvarez, M. Gallegos

Vol. 3. n. 1, pp. 100-109

Abstract - The design of electric vehicles have been an exhausted source of research during the last three decades. Nowadays, many general guidelines to design the power stage of electric vehicles can be found spread out in literature. However, neither standard design procedure nor single paper has been reported which considerers the selection and design of each power stage from scratch. Therefore, the main aim of this paper is to present a standardized procedure to design the traction power stage of an electric vehicle from scratch. The procedure presented in this paper is used as a benchmark to develop the traction power stage of an experimental fuel cell, supercapacitor electric vehicle with electric differential. Fuel cell is employed to provide the average power during the driving journey. Supercapacitors supply the peak power during acceleration and they absorb the regenerate power during breaking. Finally, two induction machines connected each one to a single gear directly coupled to the rear wheels and controlled with indirect field oriented control creates an electric differential. Theoretical results of this procedure and design are verified through digital simulation, and confirmed by developing a 500kg experimental traction drive.

Keywords: Electric differential, electric vehicle, indirect field oriented control.

Analytic Design Of A Permanent Magnet Synchronous Motor Dedicated To EV Traction With A Wide Range Of Speed Operation
by B. B. Salah, A. Moalla, S. Tounsi, R. Neji, F. Sellami

Vol. 3. n. 1, pp. 110-122

Abstract - In this paper, we develop a design method of a Permanent Magnet Synchronous Motor (PMSM) in order to exploit it in the electric vehicle propulsion. We dimension our motor in a way to obtain the best dynamic performances and the reduced power consumption while taking in account the various constraints of the book specifications. Simulations of the designed prototype will be presented in order to validate the performance of the motor in interaction with the various constraints of the traction chain. The results obtained show the effectiveness of the designed motor and its good integration in the electric vehicle traction chain, as well as a good satisfaction of the constraints of the book specifications.

Keywords: Design, PMSM, electric vehicle, electric traction.

Methods of Modeling and Identifying the Electrical Characteristics of Super Capacitor Energy Storages
by Y. Cheng, J. Van Mierlo, P. Lataire

Vol. 3. n. 1, pp. 123-128

Abstract - Super capacitor energy storages have very high power density and low energy density in comparison with battery energy storages. So it is important to well configure the super capacitor energy storage as peak power unit. In this case, the simple and accurate model of super capacitors is required. Therefore, the methods of modeling and identifying the electrical characteristics of super capacitors are proposed in this paper. Based on the detected parameters, the modeling of super capacitors is evaluated both in simulation system and in the test setup of a dedicated passenger car in ECE15 cycle. Finally the methods of identifying and balancing voltage difference of super capacitor energy storage are also presented, which can ensure high available energy capacity and long life time of super capacitors.

Keywords: Super capacitor, modeling, power density, energy storage, self-discharging.

Analysis of a Cylindrical Passive Suspension System Using Finite Element Method
by A. Najjar-Khodabakhsh, S. Vaez-Zadeh, A. H. Isfahani

Vol. 3. n. 1, pp. 129-135

Abstract - The analysis of cylindrical suspension systems has usually been carried out by their approximated flat structures so far. In this paper the lift and drag forces of a passive electrodynamic suspension system, consisting of a permanent magnet block levitated over a rotating cylindrical conducting shell, is fully investigated with no structural approximation. A FEM-base procedure for numerous simulation runs is followed to consider the influences of many system operating conditions and specifications on the system performance. In particular, the effects of rotating speed, shell thickness and conducting resistivity, permanent magnet dimensions and air gap length are analyzed. The concluding remarks presented in the paper can be used in the optimal design of such a suspension system.

Keywords: Electrodynamic levitation, Passive suspension, Performance, Finite element method.

The Soft-Starters Modeling, Simulations and Control Implementation for 2 MW Constant-Speed Wind Turbines
by L. Mihet-Popa, O. Prostean, I. Szeidert

Vol. 3. n. 1, pp. 136-142

Abstract - In this paper a soft-starter model and its control strategy for connecting solutions to the grid of different modes for a wind turbine generator of 2MW are evaluated. The thyristors switching for different functions of the firing angle are discussed. A complete simulation model of a constant speed wind turbine with cage rotor and double stator windings induction generator is also presented. The system model proposed in this paper is developed in the dedicated power system simulation tool DIgSILENT, which gives access to an extensive library, but requires implementation of the relevant wind turbine model. The model can be used to study alternative control strategies for wind turbines and additional equipments such as soft-starter, compensation units and storage systems.

Keywords: Constant-speed wind turbines, cage rotor induction generator, soft-starter.

Dynamic Modeling, Simulation and Control of the Power Conditioning System for a Variable-Speed Wind-Turbine
by J. Castelló, R. García-Gil, J. M. Espí, S. A. González

Vol. 3. n. 1, pp. 143-158

Abstract - This work presents the modeling, simulation and control of the power conditioning system of a grid-connected variable-speed wind-turbine. The power conditioning system is composed by two sinusoidal-pulse-with-modulated (SPWM) voltage source converters (VSC) interconnected by a dc-link. The generator-side converter is controlled to extract the maximum power for a given wind speed. The grid-side converter is controlled so that the energy is exchanged with unity displacement factor. A discrete control structure based in three control loops has been use for the grid-side converter: a first control loop is used for the correction of the displacement factor in order to obtain a current in counter-phase with the grid (for grid injection); the control of the peak current that is injected to the grid; and the control that regulates the dc-link voltage in order to allow that all the current extracted from the wind turbine is to be injected to the grid. The dynamic model of three-phase VSC is developed at synchronous reference frame with grid voltage, which permits the analisys of the performance of the proposed control with long simulation periods. Finally, the simulated results are compared with a prototype of 1.5 kW, where the wind turbine is modeled by two squirrel-cage induction motors mechanically coupled.

Keywords: Modeling, voltage source converter (VSC), sinusoidal-pulse-width modulated (SPWM), wind power generation.

Fractional Order Speed Observer for Sensorless Induction Motor Drives
by M. Ben Hamed, L. Sbita

Vol. 3. n. 1, pp. 159-165

Abstract - In this paper, a fractional speed observer for sensorless induction motor drives is proposed. For the need of the fractional observer parameter identification, Matlab functions have been implemented.
To validate the fractional speed observer either in simulation or in experimentation, an approximation based on the recursive distribution poles and zeros method is used.
Computer simulations of the fractional speed observer, for a scalar controlled induction motor, have been carried out to test the validity of the proposed observer at different operating conditions. Owing to its advantages, an Integral and Proportional (IP) controller is used for the observed rotor speed control loop.
Experimental results for 1kw induction motor are presented and analyzed using a dSpace system with DS1104 controller board based on digital signal processor TMS320C31. Digital simulations and experimental results are presented to show the improvement in performance of the proposed observation method.

Keywords: Fractional order, speed, observer, induction motor and scalar control.

Induction Motors Bearing Failures Detection and Diagnosis Using a RBF ANN Park Pattern Based Method
by I. Y. Önel, M. El H. Benbouzid

Vol. 3. n. 1, pp. 166-173

Abstract - This paper deals with the problem of bearing failure detection and diagnosis in induction motors. The proposed approach is a sensor-based technique using the mains current and the rotor speed measurement. The proposed approach is based on the stator current Park patterns. Induction motor stator currents are measured, recorded and used for Park patterns computation. A Radial Basis Function (RBF) Artificial Neural Network (ANN) is then used to automate the fault detection and diagnosis process. Experimental tests with artificial bearing damages results show that the proposed method can be used for accurate bearing failures detection and diagnosis in induction motors.

Keywords: Induction motor, bearing failure, diagnosis, Park transform, neural networks.

Design of a New Sensorless Controller of Induction Motor Using Backstepping Approach
by A. Abbou, H. Mahmoudi

Vol. 3. n. 1, pp. 174-181

Abstract - During the last years induction machines have gained a dominant role in the field of electromechanical energy conversion. In this paper, the authors propose a new sensorless controller designed by the backstepping approach for the speed control of induction motor. In this command, we also combined the method MRAS to estimate the speed of rotation and the observer type Luenburger to observe Rotor flux. The control model involves a division by the flux variable that may lead to unbounded solutions. Such a risk is avoided by basing the controller design on lyapunov function that accounts for the model singularity. On the other hand, this mixed method gives better results in Sensorless operation and especially at low and high speed. The response time at 5% of the flux is 60ms while the error between the speed with sensor and the estimated speed remains in the range of ±2 rad/s.

Keywords: Induction Motor, Backstepping approach, Sensorless MRAS, Luenburger Observer.

The Finite Element Method In Shielding Problems
by M. Lascu

Vol. 3. n. 1, pp. 182-189

Abstract - A very powerful tool for studying the magnetic field of shaped slotted screens has been developed. The proposed method is based on a circuital characterization of the structure, via the Finite Element Method (FEM), which is then combined with a modal expansion to compute the field inside and outside the envelope. Although my analysis is focused in square slotted structures, the versatility of the Finite Element Method permits one to apply this method to any bidimensional envelope no matter how many slots or dielectric parts it contains. This paper is also a review describing the basics of the finite-element method and its applications to EMI/C problems. It demonstrates how this method can help in the analysis of shield degradation in the presence of external conductors and electromagnetic leakage through slot configurations in a shielded enclosure. The development is given for an EMI application related to shield degradation in the presence of external conductors. The magnetic field inside and outside the slotted screens has been studied using the Finite Element Method. As a practical application, the magnetically performance of a slotted cylindrical and rectangular screen has been studied. In general, it is shown that coupling to the interior of slotted screens is maximized at frequencies corresponding to resonance of the shorted screen, provided that the fields do not vanish near the aperture.

Keywords: Aperture, Finite Element Method, Grid, Mesh, Shield, Source.

Combining the Moments Method and the PEEC Method With the Kron’s Transformation for Studying Embedded Systems EMC
by J. B. H. Slama, O. Maurice, D. Baudry, A. Louis, B. Mazari

Vol. 3. n. 1, pp. 190-197

Abstract - This paper presents a new approach to calculate the coupling between separate structures in embedded systems. We combine the Moments Method (MoM) and the Partial Element Equivalent Circuit (PEEC) method with the Kron’s transformation so as to calculate the coupling matrix impedance.The PEEC method is used to study the coupling with accurate details at the level of small systems such as multi-layer printed circuits boards. On another hand, the Moments Method is used to calculate the coupling between distant parts. It allows modelling of metallic structures with apertures.The Kron’s method makes it possible to reduce the coupling matrix in order to make it easier to use as well as to calculate the coupling between separated patterns coming from various computations.This methodology is applied to a simple structure constituted by two square circuits and experimental measurements will validate the results obtained.

Keywords: Moments Method (MOM), Partial Element Equivalent Circuit (PEEC) method, Kron’s transformation, circuit couplings, impedance matrix.

A Dual-Function RF Filter for 5GHz WLAN and UWB with Narrowband Interference Rejection
by A. Dinh, L. Chen, D. Teng, B. Pham

Vol. 3. n. 1, pp. 198-207

Abstract - This paper presents a fully integrated dual-function filter to be used in a proposed low-cost RF receiver front-end topology that resolved the Narrowband Interference to an ultra-wideband (UWB) receiver. The filter design utilizes high Q passive devices and Q-enhancement technique to provide channel selection in NB operation and NBI rejection in UWB operation. Using NB function for the 802.11a NB, the filter has a tunable gain of 4 to 25dB, a Noise Figure of 8dB and an IIP3 of -47dBm. The operating frequencies are from 5.15GHz to 5.35GHz. The input impedance matching is -16dB. Using in the UWB receiver for the frequencies across 3.1GHz to 9GHz, the filter has a gain of 0 to 8dB. The filter can reject the NB interference from 5.15GHz to 5.35GHz at up to 60dB. The Q of the filter is tunable up to 250 while consuming a maximum of 23.4mW of power and occupies a die area of 1.1mm².

Keywords: Dual-function RF Filter, NB Interference Rejection, LNA for UWB, Integrated Transformer, Q-enhancement technique.

On the Study of Modernized Lightning Air Terminal
by M. A. B. Sidik, H. Ahmad

Vol. 3. n. 1, pp. 208-217

Keywords: Lightning, Lightning Protection System, Lightning Air Terminal.

The Contribution of Vehicle Headlights to Visibility of Targets in Road Lighting Environments
by A. Ekrias, M. Eloholma, L. Halonen

Abstract - In this paper road lighting measurements were made to study the impacts of vehicle headlights on luminance contrasts of targets located on the road. Experimental measurements were made on a highway to investigate the contribution of halogen and high-intensity discharge headlights to road lighting. The measurement results indicate that in general, the use of vehicle headlights, in the presence of road lighting, does not improve the luminance contrasts of targets located on the road. The impacts of vehicle headlights are highly dependent on the vehicle, headlights type, target reflection factor, position of the target, position of the vehicle and road lighting installation. The effects of HID headlights on targets luminance contrasts were more significant compared to the ones of halogen headlights.

Keywords: Road lighting, vehicle headlights, luminance measurement, luminance contrast, target visibility.

International Review of Electrical Engineering - February 2008 - Papers

Overvoltage Protection Optimization of Medium Voltage Network

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