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29,922 Article Results

Review of DC Offset Compensation Techniques for Grid Connected Inverters

10.11591/ijpeds.v9.i2.pp478-494
Ahmed Omar Elghareeb , Adel Mohamed Elrefaey , Mona Fouad Moussa , Yasser Gaber Dessouky
Limitations of DC injection into the AC network is an important operational requirement for grid connected photovoltaic systems. There is one way to ensure that this issue needs a power transformer as a connection to the AC network. However, this solution adds cost, volume, mass, and power losses. Ideally there shouldn't be any DC at the output of the inverter, but practically, a small amount of DC current is present. Therefore, in this paper there are techniques for the DC offset elimination are proposed. Some have drawbacks which was treated by another technique. Also there are best solutions for eliminating DC offset as in section 17, and 18 as it explains how to reduce the DC offset in a transformerless operation with reducing the power losses, mass and the cost effect.
Volume: 9
Issue: 2
Page: 478-494
Publish at: 2018-06-01

Modeling and Simulation of Fuzzy Logic based Maximum Power Point Tracking (MPPT) for PV Application

10.11591/ijece.v8i3.pp1315-1323
Ahmad Saudi Samosir , Herri Gusmedi , Sri Purwiyanti , Endah Komalasari
This paper presents modeling and simulation of maximum power point tracking (MPPT) used in solar PV power systems. The Fuzzy logic algorithm is used to minimize the error between the actual power and the estimated maximum power.  The simulation model was developed and tested to investigate the effectiveness of the proposed MPPT controller. MATLAB Simulink was employed for simulation studies. The proposed system was simulated and tested successfully on a photovoltaic solar panel model. The Fuzzy logic algorithm succesfully tracking the MPPs and performs precise control under rapidly changing atmospheric conditions. Simulation results indicate the feasibility and improved functionality of the system.
Volume: 8
Issue: 3
Page: 1315-1323
Publish at: 2018-06-01

Dual Axes Solar Tracker

10.11591/ijece.v8i3.pp1887-1892
Ahmad Imran bin Ibrahim , Farah Diyana binti Abdul Rahman , Muazzin bin Rohaizat
Photovoltaic (PV) is one of the most important sources of renewable energy in the world. Its current efficiency could be increased up to 60% by using dual axes solar tracker, which maximise PV exposure to sun. The most important component in dual axes solar tracker is sensing location of the sun. Four light dependent resistors (LDR) are used as the sensors, connected to potentiometers to increase their accuracy. Arduino UNO is used as the controller to control two stepper motors. Two experiments have been carried out, where the tolerance of the LDR has been found to be 0.05V and the calibration of the four LDRs to have the error of 0.03V. Both experiments proved the capability of LDR for dual axes solar tracker and potentiometer to increase their accuracy.
Volume: 8
Issue: 3
Page: 1887-1892
Publish at: 2018-06-01

Modelling and Parameters Identification of a Quadrotor Using a Custom Test Rig

10.11591/ijpeds.v9.i2.pp865-872
Mohammad Shafiq Mohammad Ashraf , Mohamad Shukri Zainal Abidin , Mohd Saiful Azimi Mahmud , Muhammad Khairie Idham Abd Rahman , Zakarya Mohammed Nasser Saleh Motea
Quadrotor by nature is a very unstable system and flying it without any feedback control algorithm is deemed impossible. However, before designing the control system, system identification need to be conducted as the accuracy of the control system depends highly on the accuracy of the model. Therefore, this paper explained the design of the quadrotor model with an “X” configuration using the Euler-Newton model. Two types of test rig were designed to measure the thrust coefficient, torque coefficient and throttle command relation parameter needed in the model. Other parameter such as moment of inertia was also being measured by separating the quad rotor model into several sections: Motors, Electronics Speed Controllers (ESC) and Central Hub. All parameters needed in the designed quad rotor model has been successfully identified by measuring the parameters using the custom-built quad rotor and test rigs. The parameters found in this paper will be used in designing the control system for the quadrotor.
Volume: 9
Issue: 2
Page: 865-872
Publish at: 2018-06-01

Dynamic Frequency Scaling Regarding Memory for Energy Efficiency of Embedded Systems

10.11591/ijece.v8i3.pp1798-1804
Junha Kim , Moonju Park
Memory significantly affects the power consumption of embedded systems as well as performance. CPU frequency scaling for power management could fail in optimizing the energy efficiency without considering the memory access. In this paper, we analyze the power consumption and energy efficiency of an embedded system that supports dynamic scaling of frequency for both CPU and memory access. The power consumption of the CPU and the memory is modeled to show that the memory access rate affects the energy efficiency and the CPU frequency selection. Based on the power model, a method for frequency selection is presented to optimize the power efficiency which is measured using Energy-Delay Product (EDP). The proposed method is implemented and tested on a commercial smartphone to achieve about 3.3% - 7.6% enhancement comparing with the power management policy provided by the manufacturer in terms of EDP.
Volume: 8
Issue: 3
Page: 1798-1804
Publish at: 2018-06-01

Evaluation of Synchronization and MPPT algorithms in a DFIG Wind Turbine Controlled by an Indirect Matrix Converter

10.11591/ijpeds.v9.i2.pp784-794
Ahmad Khajeh , Reza Ghazi , Mohamad Hosseini Abardeh , Mahmoud Oukati Sadegh
Most of generators utilized in wind turbines are the Doubly-Fed Induction Generator (DFIG). Indirect matrix converter (IMC) is a candidate for substituting the traditional back-to-back converter in the future due to advantages gained by elimination of electrolytic capacitor. Starting DFIG wind turbines and synchronizing to the grid is a challenge in practice because of large inrush currents that could damage switches. Synchronizing the DFIG wind turbine controlled by the IMC is presented in this paper. Also, maximum power point tracking algorithm performance of this configuration is examined. A laboratory scale prototype of the proposed configuration is built. Experimental results have confirmed effectiveness of this configuration.
Volume: 9
Issue: 2
Page: 784-794
Publish at: 2018-06-01

Soft Frequency Reuse (SFR) in LTE-A Heterogeneous Networks based upon Power Ratio Evaluation

10.11591/ijece.v8i3.pp1569-1576
Alvita Maurizka , F. Hamdani , M. M. Ulfah , Iskandar Iskandar
As the traffic demand grows and the RF environment changes, the mobile network relies on techniques such as SFR in Heterogeneous Network (HetNet) to overcome capacity and link budget limitation to maintain user experience. Inter-Cell Interference (ICI) strongly affecting Signal-to-Interference plus Noise Ratio (SINR) of active UEs, especially cell-edge users, which leads to a significant degradation in the total throughput. In this paper we evaluate the performance of SFR with HetNet system in order dealing with interferences. Simulation result shows that the power ratio control in SFR HetNet system doesn’t have much effect on total achieved capacity for overall cell.
Volume: 8
Issue: 3
Page: 1569-1576
Publish at: 2018-06-01

Simulation Models of Energy Cables in SPICE

10.11591/ijpeds.v9.i2.pp744-749
Uma Balaji
Accurate modeling of cables is important to study the behavior of high frequency disturbances in power converter systems. This paper reviews and compares two popular methodologies to model energy cables – an improved per unit length parameters based model and a Laplace SPICE element based model. The two models presented take into account the frequency dependence of the parameters of the cable. A ladder network is used for this purpose in the per unit length based model. The Laplace SPICE element model is generated from from a rational function approximation for the admittance parameters that are frequency dependant. The rational function approximation is obtained using a well known vector fitting algorithm.  The time and frequency domain solutions of a two wire energy cable, obtained from the two models, agree well.
Volume: 9
Issue: 2
Page: 744-749
Publish at: 2018-06-01

A Compact Dual Band Elliptical Microstrip Antenna for Ku/K Band Satellite Applications

10.11591/ijece.v8i3.pp1596-1601
Mohamed Mahfoudh Harane , Hassan Ammor
This paper presents an original elliptical microstrip patch antenna is proposed for Ku/K band satellite applications. The proposed antenna has a simple structure, small size with dimensions of about 10×12×1.58 mm³. The antenna has been designed and simulated on an FR4 substrate with dielectric constant 4.4 and thickness of 1.58 mm. The design is simulated by two different electromagnetic solvers. The results from the measured data show that the antenna has two resonant frequencies that define 2 bandwidths, defined by a return loss of less than -10 dB, and are: (14.44 GHz, 829 MHz) and (21.05 GHz, 5126 MHz),with the gain 5.59 dB and 5.048 dB respectively. The proposed antenna can be used in many applications such as in satellite, and wireless communications.
Volume: 8
Issue: 3
Page: 1596-1601
Publish at: 2018-06-01

Fusion of Random Projection, Multi-Resolution Features and Distance Weighted K Nearest Neighbor for Masses Detection in Mammographic Images

10.11591/ijeecs.v10.i3.pp1030-1035
Viet Dung Nguyen , Minh Dong Le
Breast cancer is the top cancer in women both in the developed and the developing world. For early detection of the disease, mammography is still the most effective method beside ultrasound and magnetic resonance imaging. Computer Aided Detection systems have been developed to aid radiologists in diagnosing breast cancer. Different methods were proposed to overcome the main drawback of producing large number of False Positives.  In this paper, we presented a novel method for masses detection in mammograms. To describe masses, multi-resolution features were utilized. In feature extraction step, we calculated multi-resolution Block Difference Inverse Probability features and multi-resolution statistical features. Once the descriptors were extracted, we deployed random projection and distance weighted K Nearest Neighbor to classify the detected masses. The result is quite sanguine with sensitivity, false positive reduction and time for carrying out the algorithm
Volume: 10
Issue: 3
Page: 1030-1035
Publish at: 2018-06-01

Dynamic Voltage Stability Comparison of Thermal and Wind Power Generation with Different Static and Dynamic Load Models

10.11591/ijece.v8i3.pp1401-1411
Lina F. Acevedo , Gilbert Bothia-Vargas , John Edwin Candelo
This paper presents a static and dynamic voltage stability analysis of a power network with thermal and wind generation considering static and dynamic load models. The thermal plant was modeled as a synchronous machine and the wind farm as a variable speed induction generator based on a doubly-fed induction generator. The load considered the ZIP, exponential recovery, induction motor, and frequency-dependent load models. The bifurcation points were found by continuation power flow and sensitivity analyses. In addition, dynamic voltage stability assessments were performed considering changes in the moment of inertia and the frequency parameters. All simulations were carried out in a 4-bus power system and using the power system analysis toolbox (PSAT) and MATLAB script code. The results show that the thermal generator had difficulties to maintain stability under dynamic load variations and frequency changes, the wind generator had difficulties to maintain voltage for the load with induction motors, and both generators had difficulties when the moment of inertia is increased.
Volume: 8
Issue: 3
Page: 1401-1411
Publish at: 2018-06-01

A Survey of Machine Learning Techniques for Self-tuning Hadoop Performance

10.11591/ijece.v8i3.pp1854-1862
Md. Armanur Rahman , J. Hossen , Venkataseshaiah C , CK Ho , Tan Kim Geok , Aziza Sultana , Jesmeen M. Z. H. , Ferdous Hossain
The Apache Hadoop framework is an open source implementation of MapReduce for processing and storing big data. However, to get the best performance from this is a big challenge because of its large number configuration parameters. In this paper, the concept of critical issues of Hadoop system, big data and machine learning have been highlighted and an analysis of some machine learning techniques applied so far, for improving the Hadoop performance is presented. Then, a promising machine learning technique using deep learning algorithm is proposed for Hadoop system performance improvement.
Volume: 8
Issue: 3
Page: 1854-1862
Publish at: 2018-06-01

Modeling and Nonlinear Control of a Wind Turbine System Based on a Permanent Magnet Synchronous Generator Connected to the Three-phase Network

10.11591/ijpeds.v9.i2.pp766-774
Yasser Boussairi , Abdelmajid Abouloifa , Ibtissam Lachkar , Abdellatif Hamdoun , Chaouqi Aouadi
This article presents nonlinear control of wind conversion chain connected to the grid based on a permanent magnet synchronous generator. The control objectives are threefold; i) forcing the generator speed to track a varying reference signal in order to extract the maximum power at different wind speed (MPPT); ii) regulating the rectifier output capacitor voltage; iii) reducing the harmonic and reactive currents injected in the grid. This means that the inverter output current must be sinusoidal and in phase with the AC supply voltage (PFC). To this end, a nonlinear state-feedback control is developed, based on the average nonlinear model of the whole controlled system. This control strategy involves backstepping approach, Lyapunov stability and other tools from theory of linear systems. The proposed state-feedback control strategy is tested by numerical simulation which shows that the developed controller reaches its objectives
Volume: 9
Issue: 2
Page: 766-774
Publish at: 2018-06-01

An Empirical Comparative Study of Instance-based Schema Matching

10.11591/ijeecs.v10.i3.pp1266-1277
Mogahed Alzeber , Ali A. Alwan , Azlin Nordin , Abedallah Zaid Abualkishik
The main issue concern of schema matching is how to support the merging decision by providing matching between attributes of different schemas. There have been many works in the literature toward utilizing database instances to detect the correspondence between attributes. Most of these previous works aim at improving the match accuracy. We observed that no technique managed to provide an accurate matching for different types of data. In other words, some of the techniques treat numeric values as strings. Similarly, other techniques process textual instance, as numeric, and this negatively influences the process of discovering the match and compromising the matching result. Thus, a practical comparative study between syntactic and semantic techniques is needed. The study emphasizes on analyzing these techniques to determine the strengths and weaknesses of each technique. This paper aims at comparing two different instance-based matching techniques, namely: (i) regular expression and (ii) Google similarity to identify the match between attributes. Several analyses have been conducted on real and synthetic data sets to evaluate the performance of these techniques with respect to Precision (P), Recall (R) and F-Measure.
Volume: 10
Issue: 3
Page: 1266-1277
Publish at: 2018-06-01

Analysis and Design of Single Phase High Efficiency Transformer less PV Inverter Topology

10.11591/ijpeds.v9.i2.pp730-737
Jayalakshmi N. S. , Ankit Kumar , Ashish Kumar
An inclination towards renewable energy resources has been increased due to the requirement of clean environment and to satisfy the increasing power demand for the long run. A grid connected system requires the availability of a transformer in its power conversion stages that provides galvanic isolation between the grid and the power system. But inclusion of transformer results in making the system bulky and more expensive. In this paper different transformer-less PV inverter topologies are analyzed by comparing their efficiency, leakage current and THD of load current using MATLAB/Simulink environment. In order to achieve maximum power, maximum power point tracking (P&O algorithm) is used. From the simulation results, modified HB-ZVR is found to have minimum leakage current and constant common mode voltage with higher efficiency. Also, the hardware results are obtained for modified HB-ZVR topology.
Volume: 9
Issue: 2
Page: 730-737
Publish at: 2018-06-01
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