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23,598 Article Results

Modeling FACTS Devices in Power System State Estimation

https://ijece.iaescore.com/index.php/IJECE/article/view/5371
Seyyed Mehdi Mahaei , Mehrdad Tarafdar Hagh , Kazem Zare
In this paper is modeled different types of control devices including various kinds of FACTS devices based on power system states. Also, the impact of each device on the amount of injection active or reactive powers as well as active and reactive power flow will be investigated. Based on the type of these devices which can be in parallel, in series or in series–shunt in power systems, proposed models is considered differently. Accordingly, case studies will be performed for three different types of control devices installed in series, in shunt and in series-shunt fashions. State estimation results based on Weighted Least Square not only confirm the proposed models’ effectiveness in accurately state estimating of the system and measurement values but also shows that the estimated values can be obtained from the states of the control devices.Keywords: State Estimation; FACTS Devises; Measurement Function; WLS EstimatorDOI:http://dx.doi.org/10.11591/ijece.v2i1.132
Volume: 2
Issue: 1
Page: 57-67
Publish at: 2011-11-13

Performance of Governor System on Minimizing Frequency Fluctuations with Wind Power Generation

https://ijece.iaescore.com/index.php/IJECE/article/view/5370
Dr. Md. Rafiqul Islam Sheikh , Md. Mejbaul Haque , M.A. Hossain
As wind turbine output is proportional to the cube of wind speed, the wind turbine generator output fluctuates due to wind speed variations. Hence, if the power capacity of wind power generators becomes large, wind power generator output can have an influence on the power system frequency. Therefore, this study investigates the influence of governor control systems of synchronous generators (SGs) for minimizing frequency fluctuations with high wind power penetration level, when a total capacity of SGs is considered as 100 MVA. It is seen that when both SGs operate as governor free (GF) operation, system perform better frequency control. But it can not be maintained to the acceptable level when SGs operate at GF-LFC or LFC-GF operation with wind power capacity about 5% of total capacity. Finally, it is seen that when several interconnected SGs are operated with different control modes, system frequency become more severe for 10% capacity of wind power.DOI:http://dx.doi.org/10.11591/ijece.v2i1.180
Volume: 2
Issue: 1
Page: 46-56
Publish at: 2011-11-13

Parametric Investigation of Near End and Far End Crosstalks in Printed Circuit Board Lands

https://ijece.iaescore.com/index.php/IJECE/article/view/40
Md. Masud Rana , Md. Rabiul Islam , Md Kamal Hosain
Multi-conductor transmission line and interconnect carry signals with wide rage of frequencies from sending end to receiving end. The signal in one transmission line may be interupted by the unwanted contributions from the neighboring line conductors. If data speed increases, high frequency effects occur and the signals suffer from difficulties such as ringing, crosstalk, reflections, and ground bounce that seriously hamper the quality of the received signal. In order to estimate the signal quality, signal integrity analysis is needed. In this paper, an attempt has been made to investigate the sensitivity of the near and far end crosstalk on the parameters such as physical geometry of the conductors, electrical property of the substrate and the rise and fall time of excitation signal. The method of moments (MOM) is used to calculate the line parameters for different geometries. The simulation studies are carried out in TNT. The time domain and frequency domain analyses are performed using transmission line model of PSPICE. Moreover, a model is developed and tested in the laboratory. It is observed that the coupling inductance and capacitance vary with the variation of physical geometry and the substrate parameter.DOI:http://dx.doi.org/10.11591/ijece.v1i2.164
Volume: 1
Issue: 2
Page: 213-219
Publish at: 2011-11-13

A Survey Report On Elliptic Curve Cryptography

https://ijece.iaescore.com/index.php/IJECE/article/view/39
Samta Gajbhiye , Monisha Sharma , Samir Dashputre
The paper presents an extensive and careful study of elliptic curve cryptography (ECC) and its applications. This paper also discuss the arithmetic involved in elliptic curve  and how these curve operations is crucial in determining the performance of cryptographic systems. It also presents  different forms of elliptic curve in various coordinate system , specifying which is most widely used and why. It also explains how isogenenies between elliptic curve  provides the secure ECC. Exentended form of elliptic curve i.e hyperelliptic curve has been presented here with its pros and cons. Performance of ECC and HEC is also discussed based on scalar multiplication and DLP. Keywords: Elliptic curve cryptography (ECC), isogenies, hyperelliptic curve (HEC) , Discrete Logarithm Problem (DLP), Integer  Factorization , Binary Field, Prime FieldDOI:http://dx.doi.org/10.11591/ijece.v1i2.86
Volume: 1
Issue: 2
Page: 195-201
Publish at: 2011-11-13

Smoothing Control of Wind Farm Output Fluctuations by Fuzzy Logic Controlled SMES

https://ijece.iaescore.com/index.php/IJECE/article/view/30
Md. Rafiqul Islam Sheikh , Tamura Junji
Due to random variations of wind speed, the output power and terminal voltage of a fixed speed wind generator fluctuate continuously. These irregularities in power output are affecting both the power quality and reliability. It is reported that STATCOM/SMES (Superconducting Magnetic Energy Storage) system can significantly decrease voltage and output power fluctuations of grid connected fixed speed wind generator. But the main problem in wind generator output power smoothing is the choice of the reference output power, because it corresponds to energy storage capacity. The storage capacity of SMES that is sufficient for the smoothing control but as small as possible is very important, considering cost effectiveness. In this paper, a fuzzy logic controlled STATCOM/SMES system is proposed, in which both SMA (Simple Moving Average) and EMA (Exponential Moving Average) are used to generate output power reference. Real wind speed data are used in the simulation analyses, whichvalidate the effectiveness of the proposed control strategy. Simulation results clearly show that the proposed STATCOM/SMES system can smooth well the wind generator output power and also maintain the terminal voltage at rated level in both cases when SMA or EMA is used to generate output reference power. Finally, it is shown that reference output power generated by EMA provides better performance with reduced SMES storage capacity than that of output power generated by SMA.Keywords: Minimization of fluctuations, fixed speed wind generator, STATCOM/SMES, simple moving average (SMA) and exponential moving average (EMA), and wind farm (WF).DOI:http://dx.doi.org/10.11591/ijece.v1i2.181
Volume: 1
Issue: 2
Page: 119-134
Publish at: 2011-11-12

Indoor Positioning by LED Visible Light Communication and Image Sensors

https://ijece.iaescore.com/index.php/IJECE/article/view/34
Mohammad Shaifur Rahman , Md. Mejbaul Haque , Ki-Doo Kim
High power white LEDs are expected to replace the existing lighting technologies in near future which are also suggested for visible light communication (VLC). We proposed an algorithm for high precision indoor positioning using lighting LEDs, VLC and image sensors. In the proposed algorithm, four LEDs transmitted their three-dimensional coordinate information which were received and demodulated by two image sensors near the unknown position. The unknown position was then calculated from the geometrical relations of the LED images created on the image sensors. We described the algorithm in details. Simulation of the proposed algorithm was done and presented in this paper. This technique did not require any angular measurement which was needed in contemporary positioning algorithms using LED and image sensor. Simulation results showed that the proposed system could estimate the unknown position within the accuracy of few centimeters. Positioning accuracy could be increased by using high resolution image sensors or by increasing the separation between the image sensors.DOI:http://dx.doi.org/10.11591/ijece.v1i2.165
Volume: 1
Issue: 2
Page: 161-170
Publish at: 2011-11-12

Performance Evaluation of Channel Estimation in OFDM System for Different QAM and PSK Modulations

https://ijece.iaescore.com/index.php/IJECE/article/view/32
Surinder Singh , Hari Ram , Sandeep Singh Gill
To recover accurate transmitted data at the receiver end, the information regarding channel state derived from channel estimation methods play a very important role in any communication system. In this paper the performance evaluation of different types of QAM and PSK modulations with three different channel estimation methods in OFDM system for wireless communication in frequency domain for slow fading channel is compared. The results must be useful in OFDM based applications like IEEE 802.16(d) and equivalent standards.DOI:http://dx.doi.org/10.11591/ijece.v1i2.148
Volume: 1
Issue: 2
Page: 140-150
Publish at: 2011-11-08

A Voltage Controller in Photo-Voltaic System with Battery Storage for Stand-Alone Applications

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4879
Ganesh Dharmireddy , Moorthi S , Sudheer Hanumanthakari
This paper proposes the new voltage controller in photo-voltaic system for Stand-Alone Applications with battery energy storage. The output of the PV array is unregulated DC supply due to change in weather conditions. The maximum power is tracked with respect to temperature and irradiance levels by using DC-DC converter. The perturbation and observes algorithm is applied for maximum power point tracking (MPPT) purpose. This algorithm is selected due to its ability to withstand against any parameter variation and having high efficiency. The solar cell array powers the steady state energy and the battery compensates the dynamic energy in the system. The aim of the control strategy is to control the SEPIC converter and bi-direction DC-DC converter to operate in suitable modes according to the condition of solar cell and battery, so as to coordinate the two sources of solar cell and battery supplying power and ensure the system operates with high efficiency and behaviors with good dynamic performance. The output of DC-DC converter is converted to AC voltage by using inverter.  The AC output voltage and frequency are regulated. A closed loop voltage control for inverter is done by using unipolar sine wave pulse width modulation (SPWM). The regulated AC voltage is fed to AC standalone loads or grid integration. The overall system is designed, developed and validated by using MATLAB-SIMULINK. The simulation results demonstrate the effective working of MPPT algorithm, control strategy and voltage controller with SPWM technique for inverter in AC standalone load applications.DOI: http://dx.doi.org/10.11591/ijpeds.v2i1.127
Volume: 2
Issue: 1
Page: 9-18
Publish at: 2011-11-07

A 93.36 dB, 161 MHz CMOS Operational Transconductance Amplifier (OTA) for a 16 Bit Pipeline Analog-to-Digital Converter (ADC)

https://ijece.iaescore.com/index.php/IJECE/article/view/5376
Nordiana Mukahar , Siti Hawa Ruslan
A gain modified CMOS Operational Transconductance Amplifier (OTA) for a 16 bit pipeline Analog-to-Digital Converter (ADC) is presented. The circuit is designed to be used for a high resolution and low sampling rate ADC. Gain boosting technique is implemented in the design to achieve high DC gain and settling time as required. Post layout simulations for a 5 pF load capacitance shows that OTA achieves a gain bandwidth of 161 MHz at a phase margin 93.14o with 93.27 dB DC gain. The settling time for an OTA is 163 ns for 0.1 % accuracy to achieve final value and consume power about 4.88 mW from 5 V power supply.Keywords: ADC; common mode feedback; CMOS Operational Amplifier; fully differential folded cascadeDOI:http://dx.doi.org/10.11591/ijece.v2i1.121
Volume: 2
Issue: 1
Page: 106-111
Publish at: 2011-11-07

Microcontroller Based Single Phase Digital Prepaid Energy Meter for Improved Metering and Billing System

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4872
Md. Mejbaul Haque , Md. Kamal Hossain , Md. Mortuza Ali , Md. Rafiqul Islam Sheikh
This paper presents a single phase digital prepaid energy meter based on two microcontrollers and a single phase energy meter IC. This digital prepaid energy meter does not have any rotating parts. The energy consumption is calculated using the output pulses of the energy meter chip and the internal counter of microcontroller (ATmega32). A microcontroller (ATtiny13) is used as a smart card and the numbers of units recharged by the consumers are written in it. A relay system has been used which either isolates or establishes the connection between the electrical load and energy meter through the supply mains depending upon the units present in the smart card.Energy consumption (kWh), maximum demand (kW), total unit recharged (kWh) and rest of the units (kWh) are stored in the ATmega32 to ensure the accurate measurement even in the event of an electrical power outage that can be easily read from a 20×4 LCD. As soon as the supply is restored, energy meter restarts with the stored values. A single phase prepaid energy meter prototype has been implemented to provide measurement up to 40A load current and 230V line to neutral voltage.Necessary program for microcontrollers are written in c-language and compiled by Win-AVR libc compiler.DOI: http://dx.doi.org/10.11591/ijpeds.v1i2.138 
Volume: 1
Issue: 2
Page: 139-147
Publish at: 2011-11-07

A Novel Direct Torque Control Permanent Magnet Synchronous Motor Drive used in Electrical Vehicle

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4871
Yaohua Li , Ma Jian , Yu Qiang , Liu Jiangyu
In this paper, a modified direct torque control (DTC) scheme for permanent magnet synchronous motor (PMSM) is investigated, which enables low torque ripple by using an improved voltage vector selection strategy instead of switching table used in conventional DTC. Based on the control of stator flux, torque angle and torque, voltage vector selection strategy of PMSM DTC drive is proposed. In the proposed voltage vector selection strategy, the applied voltage vector is determined according to outputs of hysteresis comparators for stator flux and torque, angular position of stator flux and torque angle, which is finally synthesized by space vector modulation (SVM). Modeling and experimental results for an interior PMSM used in Honda Civic 06My Hybrid electrical vehicle are given. Simulation and experimental results show torque ripple is reduced and the total harmonics of stator current is decreased when compared those of conventional DTC. And a fixed switching frequency is obtained with the help of SVM. In addition, the proposed DTC doesn’t need any additional PI controller, which maintains the simplicity in conventional DTC.DOI: http://dx.doi.org/10.11591/ijpeds.v1i2.141Keywords: direct torque control, permanent magnet synchronous motor, electrical vehicle, torque ripple, switching frequency
Volume: 1
Issue: 2
Page: 129-138
Publish at: 2011-11-07

AVR Microcontroller Implementation for Customized Sound Generation

https://ijece.iaescore.com/index.php/IJECE/article/view/5377
Tanvir Hussain , Md Mejbaul Haque
In this paper, we have proposed a technique by which customized sound can be generated using 8 bit AVR microcontroller. Any sound file chosen from computer can be integrated in microcontroller programming which is written in C and compiled by AVR libc compiler. An 8 bit DAC connected to PORT A of AVR microcontroller takes data of  sound file as input and gives converted analog sound signal as output. An audio amplifier based on LM386 Op-Amp circuit amplifies the sound signal which is finally connected to 8Ω speaker for audible sound output. This circuit has been simulated using Proteus ISIS 7 Virtual System Modeling (VSM).DOI:http://dx.doi.org/10.11591/ijece.v2i1.139
Volume: 2
Issue: 1
Page: 112-119
Publish at: 2011-11-07

Improving Bad Data Detection in State Estimation of Power Systems

https://ijece.iaescore.com/index.php/IJECE/article/view/26
Mehrdad Tarafdar Hagh , Seyyed Mehdi Mahaei , Kazem Zare
In state estimation of power systems, it is possible that measurements include bad data, influencing on state estimations of power system. Several intelligent methods have been proposed to detect bad data which should be trained in various network situations but they are almost impractical because of abound situations of actual network. Some mathematical methods such as Chi-Square Distribution Test, Largest Normalized Residual Test and Hypotheses Testing Identification as the detectors of bad data have been presented, too. Sometimes these mathematical methods are not able to detect bad data. This paper proposes a method which can improve the detection of bad data in mentioned mathematical methods. Case studies have been done with different given errors on measurements of IEEE 14-bus system, and it was shown that this method is effective to improve the bad data detection.DOI:http://dx.doi.org/10.11591/ijece.v1i2.133 Keywords: Bad Data; Chi-Square Distribution; Largest Normalized Residual; Hypotheses Testing Identification
Volume: 1
Issue: 2
Page: 85-92
Publish at: 2011-11-05

Design Optimization of High-Frequency Power Transformer by Genetic Algorithm and Simulated Annealing

https://ijece.iaescore.com/index.php/IJECE/article/view/28
Amit Kumar Yadav , O. P. Rahi , Hasmat Malik , Abdul Azeem
This paper highlights the transformer design optimization problem. The objective of transformer design optimization problem requires minimizing the total mass (or cost) of the core and wire material by satisfying constraints imposed by international standards and transformer user specification. The constraints include appropriate limits on efficiency, voltage regulation, temperature rise, no-load current and winding fill factor. The design optimizations seek a constrained minimum mass (or cost) solution by optimally setting the transformer geometry parameters and require magnetic properties. This paper shows the above design problems can be formulated in genetic algorithm(GA) and simulated annealing (SA) format. The importance of the GA and SA format stems for two main features. First it provides efficient and reliable solution for the design optimization problem with several variables. Second, it guaranteed that the obtained solution is global optimum. This paper includes a demonstration of the application of the GP technique to transformer design.Key word—Optimization, Power Transformer, Genetic Algorithm (GA), Simulated Annealing Technique (SA)DOI:http://dx.doi.org/10.11591/ijece.v1i2.88
Volume: 1
Issue: 2
Page: 102-109
Publish at: 2011-10-29

Direct Instantaneous Torque Control of 4 Phase 8/6 Switched Reluctance Motor

https://ijpeds.iaescore.com/index.php/IJPEDS/article/view/4870
Srinivas Pratapgiri , P.V.N. Prasad
The applications of Switched Reluctance Motor Drives has increased  in the recent past because of advantages like simple structure, no rotor winding, high torque to weight ratio, adaptability to harsh environments like coal mining etc. But the main disadvantage is that torque ripple is high because of the double saliency. This paper presents a high dynamic control technique called Direct Instantaneous Torque Control (DITC) where in the torque is maintained within a hysteresis band by changing the switching states of the phases between 1, 0 or -1.Thus torque ripple minimization is an inherent property of DITC. DITC based SRM drive is simulated in MATLAB/SIMULINK environment and results are discussed elaboratelyDOI: http://dx.doi.org/10.11591/ijpeds.v1i2.102
Volume: 1
Issue: 2
Page: 121-128
Publish at: 2011-10-29
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