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30,895 Article Results

Modified SEPIC Converter Performance for Grid-connected PV Systems under Various Conditions

10.12928/telkomnika.v16i6.10148
Rizky Ajie; Universitas Negeri Semarang Aprilianto , Subiyanto; Universitas Negeri Semarang Subiyanto , Tole; Universitas Ahmad Dahlan Sutikno
Step-up converter is widely used to increase DC voltage level on PV systems either off-grid or grid connected. One of the step-up converters often used in PV systems is SEPIC converter. To improve its performance, many SEPIC converters have been modified. However, performance on various conditions has not been further investigated. In this study, the modified SEPIC converter was investigated under various change conditions for grid-connected PV applications. This converter was modelled and simulated using PSIM software. The modified SEPIC converter received input from PV array 15 kWp, and its output was connected to the three-phase inverter with grid and load. The irradiance level and ambient temperature were varied to test its performance and compared to Boost converter and SEPIC converter. For all tests, the performance of modified SEPIC converter was better than other step-up converters because it was able to rectify the quality of output voltage and more efficient.
Volume: 16
Issue: 6
Page: 2943-2953
Publish at: 2018-12-01

A New Photovoltaic Energy Sharing System between Homes in Standalone Areas

10.11591/ijece.v8i6.pp4855-4862
A. Mezouari , R. Elgouri , M. Igouzal , M. Alareqi , K. Mateur , H. Dahou , L. Hlou
Today, global energy consumption is dominated by fossil fuels such as oil, coal and gas. The intensive consumption of these energy sources gives rise to greenhouse gas emissions and therefore an increase in CO2 emissions. Photovoltaic energy has persistently been considered as a green and pollution-free renewable energy source to overcome greenhouse effect and energy crisis. This paper describes a new method of photovoltaic energy sharing in standalone micro-grids using photovoltaic panels. This approach is based on automatic electrical energy sharing depending on the state of charge (SOC) of the electrical storage unit using by each home and on the electrical power consumption of each home.The monitoring system is connected to each home in micro-grid, it manage each home’s energy use, and assigns more energy to a large energy-consuming home. This architecture contributes to reducing total energy lost.
Volume: 8
Issue: 6
Page: 4855-4862
Publish at: 2018-12-01

New technique combining the Tone Reservation method with Clipping technique to reduce the Peak-to-Average Power Ratio

10.11591/ijece.v8i6.pp5215-5226
Hajar Abdelali
Nonlinear distortions and impairments appear in multicarrier signal with high fluctuations when amplified by a Radio Frequency Power Amplifier (RF PA). Clipping (CL) technique offers a simple way to reduce these fluctuations in Orthogonal Frequency Division Multiplexing (OFDM) Technique, but may degrade seriously the transmission quality. This is why the new mobile standards propose other methods, like the Tone Reservation (TR) technique in the Digital Video Broadcasting-Terrestrial (DVB-T), that reduce the Peak-to-Average Power Ratio (PAPR) without reaching optimal performances. This paper deals with how we can use the TR technique, which exploits null sub-carriers for generating corrective signal, in combining to CL technique in order to improve PAPR reduction without data loss. Also, we show some comparison results on the PAPR reduction obtained with proposed scheme and other techniques. Experiments using a simulated example on a complete WiMax 802.16e transmitter have been made in order to investigate the PAPR reduction performances on presence of the non-linear Power Amplifier model based on gain compression response and phase distortion.
Volume: 8
Issue: 6
Page: 5215-5226
Publish at: 2018-12-01

Radial Derivative and Radial Inversion for Interpreting 4D Gravity Anomaly Due to Fluids Injection Around Reservoir

10.12928/telkomnika.v16i6.9468
Muhammad; Universitas Gadjah Mada Zuhdi , Sismanto; Universitas Gadjah Mada Sismanto , Ari; Universitas Gadjah Mada Setiawan , Jarot; Universitas Gadjah Mada Setyowiyoto , Adi; Universitas Brawijaya Susilo , Muhammad; Universitas Lampung Sarkowi
The 4D gravity or time lapse gravity has been used many reseracher to identify fluid injection in oil reservoir. The objective of this study is to find the better way in interpreting 4D gravity anomaly due to fluid injection around the reservoir. Radial Derivatives are derivative values of gravity anomalies against horizontal distances in the radial direction. Radial inversion is a two-dimensional inversion of lines with radial directions resulting in a 3-dimension model. Time lapse microgravity research have been performed in “X Oil Field” with amount of 604 data point covering area of 4000m x 5000m. This Radial derivative and Radial inversion have been aplied at an injection well of the X oil field. The yield show that 4D gravity anomaly value due to injection is 0.02 mGal to 0.36 mGal. Radial derivative value in the area is 0 micro Gal/cm to 0,012 mGal/meter. Radial inversion shows radius of fluid front movement is 304 meters to 1120 meters. Radial derivative and Radial inversion have been proven fairly good to identify injected fluid movement in the reservoir.
Volume: 16
Issue: 6
Page: 2855-2863
Publish at: 2018-12-01

Design of Tunable Multiband Hybrid Graphene Metal Antenna in Microwave Regime

10.11591/ijeecs.v12.i3.pp1003-1009
Hussein A. Abdulnabi , Yasin Yousif Al-Aboosi
Graphene is an allotrope (form) of carbon consisting of a single layer of carbon atoms arranged in an hexagonal lattice. It is the basic structural element of many other allotropes of carbon, such as graphite, charcoal, carbon nanotubes and fullerenes. In this paper, a tunable hybrid metal-graphene antenna in the microwave regime is proposed. This antenna composed of the copper patch and four graphene strips. The antenna designs used for the cellular long-term evolution system and the operating frequency bands of 1.8, 2.5, 2.6, and 3.6 GHz, are evaluated to demonstrate the working principle and the performance tradeoffs. Furthermore, the proposed antenna can be tuned by varying applied DC voltage on the graphene which leads to change in the chemical potential of the graphene and hence the surface conductivity and electrical properties are changed. The simulation results reveal that the antenna operates in multi-band where scattering factor S11< -10 dB. In addition, the results show that hybrid metal-graphene frequency reconfigurable antennas can, at the same time, provide a tunable bandwidth and antenna matching.
Volume: 12
Issue: 3
Page: 1003-1009
Publish at: 2018-12-01

Design Mobile App for Increase the Visitor Museum using Gamification Method

10.12928/telkomnika.v16i6.10384
Novian Adi; Universitas Atma Jaya Yogyakarta Prasetyo , Suyoto; Universitas Atma Jaya Yogyakarta Suyoto
The museum's tourism object currently has a low visitor level compared to other tourism objects, even though the museum's function is very important as an enhancer of people's cultural knowledge. Judging from the small level of visitors, it cannot be separated from the effects of the promotion carried out by the museum. From the surveys that have been conducted, museum promotion uses social media more directly to the public, banners, radio, television, blogs and internet social media. In this study, an application that serves to promote museums using gamification methods was designed, this method was chosen because of the many existing promotional techniques, there is still little promotion using game content, therefore the gamification method is expected to encourage the motivation of users to visit the museum. This application will provide convenience to the museum management to promote the museum with media game content without having to spend large development and maintenance costs.
Volume: 16
Issue: 6
Page: 2791-2798
Publish at: 2018-12-01

Analysis Predicted Location of Harmonic Distortion in RF Upconverter Structure

10.12928/telkomnika.v16i6.7628
Sirmayanti; The State Polytechnic of Ujung Pandang Sirmayanti , Mike; Victoria University Faulkner
A new mathematical analysis to predict the magnitude size of the distortion products from the signal up-conversion process output is presented. The signal up-conversion process converts the digital baseband from the analog baseband into a radio frequency signal. When the signal baseband involves frequency offsetting then occurring a number of distortion products which can reduce the dynamic range so it is difficult to meet the spectrum mask requirements within the operating band. This paper will focus on methods of new mathematical analysis using a continuous frequency range and only applies to a single side band tone, with constant amplitude into any value of frequency offsets. The novel contribution to the analysis starts at generating the gate signal and convolution of the gate signal into the reference carrier signal. The results show very close between the simulation results and the calculation of the predicted location of the distortions.
Volume: 16
Issue: 6
Page: 2608-2615
Publish at: 2018-12-01

Electromagnetic Characteristics Measurement of Organic Material Absorber

10.12928/telkomnika.v16i6.9687
Reza; Centre of Electronics Technology Septiawan , Sardjono; Centre of Electronics Technology Trihatmo , Juliati; Centre of Electronics Technology Junde , Dody A.; Center of Polymer Technology Winarto , Arief; Centre of Electronics Technology Rufiyanto , Erik Madyo; Centre of Electronics Technology Putro , Budi; Centre of Electronics Technology Sulistya , Arky; Centre of Electronics Technology Astasari
Electro Magnetic Compatibility (EMC) Chamber requires high performance absorber material to assure the quality of EMC chamber related to Radio Frequency (RF) shielding effectiveness of the corresponding chamber. RF shielding effectiveness is measured following EN 50147-1 testing method. EMC laboratory of BPPT (Indonesian Agency for the Assessment and Application of Technology uses polyurethane absorber material which absorbs the carbon-neoprene mixture to maintain consistent RF performance over a broad frequency band, especially in the frequency range of CISPR 22 radiated emission test between 30 MHz to 6 GHz, limits in CISPR 22 (Information technology equipment-radio disturbance characteristics-limits and methods of measurement). This paper proposes alternative absorber materials based on organic materials: rice husk, coconut husk, cotton and sawn wood crumbs. In the early phase of this research, the frequency under consideration are 900 MHz and 1800 MHz. These frequencies are mostly used by mobile phone devices, therefore at this phase the resulted organic material absorber may be used for alternative mobile phone casing before to be used as absorber material for EMC laboratory in a broader frequency band. The organic materials are produced by mixing them with cement, carbon, and resin. Free space testing method is used in the measurements. Results has shown a mixture of 50% coconut husk with resin absorb the most radiated emission in 900 MHz, while 30% of coconut husk will absorb the most radiated emission in 1800 MHz.
Volume: 16
Issue: 6
Page: 2507-2513
Publish at: 2018-12-01

An Adaptive Internal Model for Load Frequency Control Using Extreme Learning Machine

10.12928/telkomnika.v16i6.11553
Adelhard Beni; Hiroshima University Rehiara , He; Hiroshima University Chongkai , Yutaka; Hiroshima University Sasaki , Naoto; Hiroshima University Yorino , Yoshifumi; Hiroshima University Zoka
As an important part of a power system, a load frequency control has to be prepared with a better controller to ensure internal frequency stability. In this paper, an Internal Model Control (IMC) scheme for a Load Frequency Control (LFC) with an adaptive internal model is proposed. The effectiveness of the IMC control has been tested in a three area power system. Results of the simulation show that the proposed IMC with Extreme Learning Machine (ELM) based adaptive model can accurately cover the power system dynamics. Furthermore, the proposed controller can effectively reduce the frequency and mechanical power deviation under disturbances of the power system.
Volume: 16
Issue: 6
Page: 2879-2887
Publish at: 2018-12-01

Development of a Modular Unit of a Higher Level Framework or Tool for Basic Programming Course Teaching Through E-Learning Mode

10.12928/telkomnika.v16i6.10033
Radhika; VNR Vignana Jyothi Pathi , G.V.; DRS International School Rao , P. Rama; VNR Vignana Jyothi Krishna , P. Bharath; VNR Vignana Jyothi Kumar
This paper reports about the development of a modular unit of a higher level framework or tool whose intended objective is the creation of animated lessons for basic programming (CS1) course in computer science discipline with visual aids. The goal of such lessons is to address the difficulties faced by the novice programmers in CS1 course.This module here after referred to as ‘type writer’allows instructors to render programmes or code snippets in a live typing manner as opposed to their sudden or en-block placement on the presentation area like a Power Point Slide; a commonly used approach in the present day eLearning.This project is planned to be executed in two stages and ‘type writer’ is the outcome of the first stage. This would be combined with another two modules that are planned to be developed in the second stage, to make the complete tool. The entire tool would be developed in Action Script 3.0 language that works on Adobe Flash Platform.
Volume: 16
Issue: 6
Page: 2828-2834
Publish at: 2018-12-01

Identifying Thresholds for Distance Design-based Direct Class Cohesion (D3C2) Metrics

10.11591/ijece.v8i6.pp5318-5325
Denny Sagita , Fajar Pradana , Bayu Priyambadha
In the several phases of activity in developing a software system, there is design phase. This phase has a purpose to determine and ensure that a software requirement can be realized in accordance with customer needs. The quality of design must be a guarantee at this phase. One of an indicator of quality design is cohesion. Cohesion is the level of relatedness between elements in one component. A Higher value of cohesion can indicate that a component are more modular, has own resources, and less dependent on another component. More independent, components are easy to maintenance. There are many metrics to count how many values of cohesion in a component. One of metric is The Distance Design-Based Direct Class Cohesion (D3C2). But, many practitioners are unable to apply them. Because there is no threshold that can categories the value of cohesion. This study aims to determine the threshold of cohesion metric based on the class diagram. The result showed that the threshold of D3C2 metric is 0.41. 0.41 is the value that has the highest level of agreement with the design expert.
Volume: 8
Issue: 6
Page: 5318-5325
Publish at: 2018-12-01

Design of Compact Dual Band Circular Polarized Micro-strip Antenna for High Efficiency WLAN 802.11ax-2019

10.11591/ijict.v7i3.pp135-140
Syed Muhammad Ali
Design of antennas for the latest upcoming standards of WLANs is considered as a key challenge in the science of Mobile Communication Engineering. Micro strip antennas are supposed to have some quality features in mobile and wireless network systems. Their weight and size are reduced and they are capable of having low power capacity. All these interesting features enabled these type of antennas suitable for the communication of IEEE 802.11ax-2019 high speed WLANs. Shape of these antennas can be designed in an efficient manner to achieve required gain and bandwidth. In this paper the concept of circular polarization has been introduced along with compact design of antennas in order to achieve return loss and axial ratio of less than -10 dB and 3dB respectively. Antenna has been designed and simulated on CST MW studio software and usage of dual bands 2.4 and 5.2GHz having circular polarization is properly elucidated for 802.11ax-2019.
Volume: 7
Issue: 3
Page: 135-140
Publish at: 2018-12-01

Design and Analysis of Broadband Elliptical Microstrip Patch Antenna for Wireless Communication

10.12928/telkomnika.v16i6.9246
Ali Khalid; Al Mustansiriyh University Jassim , Raad H.; Al Mustansiriyh University Thaher
In this paper presents the design and manufacture of a new broadband elliptical patch antenna with a microstrip feed line and optimum antenna  parameters. The antenna dimension of (30×21×1.6) mm3 and fabricated on an FR-4 epoxy substrate having relative dielectric constant ε_r=4.3, loss tangent tan (δ) =0.002 and the feed line used has characteristic impedance of 50Ω.The designed antenna has the capability of operating in the bandwidth (6.95 - 30.94) GHz and the gain (6.8) dBi. The antenna performance was modified by inserting a slots in the ground plane to achieve impedance bandwidth (when S11≤ -10dB) and slots to patch to improve the gain. The modified antenna was designed to be used for fifth generation (5G) mobile communication. The simulation results are obtained using CST software.
Volume: 16
Issue: 6
Page: 2492-2499
Publish at: 2018-12-01

Different Multilayer Substrate Approaches to Improve Array Antenna Characteristics for Radar Applications

10.12928/telkomnika.v16i6.10193
N.; National School of Applied Sciences Chater , T.; National School of Applied Sciences Mazri , M.; National School of Applied Sciences Benbrahim
The aim of this paper is to investigate deeply in multi-layer substrate technique as a way of improving the characteristics of patch array antenna for electronic scanning radar application. The basic array antenna consists of 8 patches mounted on a FR-4 substrate and operating at 3GHz frequency. The feeding technique is microstrip technology. This structure has some disadvantages as a poor gain and a narrow bandwidth. In fact, the obtained gain value does not exceed 7 dB which could be explained by the lossy nature of the FR4 substrate. On the other side, the narrow bandwidth is caused by the microstrip limitations. For this reason, the technique of multi-layer substrate is proposed in this paper. Many approaches are investigated and the distance between the layers is studied. The design and simulations of each approach are performed under the tool Advanced Design System of Keysight Company. A comparison between simulation results of all approaches including simulation results of the basic array antenna will be analyzed.
Volume: 16
Issue: 6
Page: 2588-2596
Publish at: 2018-12-01

Voltage Regulation of Boost Converter using Observer based Sliding Mode Controller

10.12928/telkomnika.v16i6.11558
Ramadhani Kurniawan; Brawijaya University Subroto , Sapriesty Nainy; Brawijaya University Sari , Zainul; Brawijaya University Abidin , Kuo Lung; National Taiwan University Lian
This study dealt with output voltage regulation of boost converter using observer based sliding mode controller comprises of adaptive PI sliding surface. Observer was designed to estimate the inductor current value, such that no sensor was required as a feedback. Adaptive PI sliding surface was constructed from the difference between estimated inductor current and its reference value. The stability of proposed method was ensured by using Lyapunov direct method. To test the system performance, numerical simulation was conducted. The result indicated that the integral absolute error value of proposed method was 0.19, which was 7 times less than sliding mode with PI sliding surface. Consequently, the proposed method was able to estimate accurately the inductor value, track the reference voltage perfectly, and show its robustness against parameter variations.
Volume: 16
Issue: 6
Page: 2896-2904
Publish at: 2018-12-01
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