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29,922 Article Results

Simplified cascade multiphase DC-DC boost power converters for high voltage-gain and low-ripple applications

10.11591/ijpeds.v12.i1.pp273-285
Pekik Argo Dahono
This paper proposes two new simplified cascade multiphase DC-DC boost power converters with high voltage-gain and low ripple. All simplifications reduce the number of active switching devices from 2N into N, where N is the phase number. The first simplification reduces the number of inductors from 2N into N+1 and increases the number of diodes from 2N into (2N+1). The second simplification reduces the number of inductors from 2N into N+1 and increases the number of diodes from 2N into (3N+1). The second simplification needs inductors with smaller current rating than the first simplification. The expressions of output voltage as a function of load current are derived by taking into account the voltage drops across the inductors and switching power devices. Simulated and experimental results are included to show the basic performance of the proposed cascade multiphase DC-DC boost power converters.
Volume: 12
Issue: 1
Page: 273-285
Publish at: 2021-03-01

Crucial problems in arranged the lesson plan of vocational teacher

10.11591/ijere.v10i1.20604
Muhammad Nurtanto , Nur Kholifah , Alias Masek , Putu Sudira , Achmad Samsudin
This study aimed to explore the implementation of the 2013 curriculum in vocational schools, Banten in terms of the readiness and quality of the learning tools that have been prepared. A total of 957 respondents from 2017 to 2018, consisting of four cities and three districts in Banten Province were involved in the training and mentoring program, namely vocational teachers and vice-principals in the curriculum field. Data were collected using questionnaire sheets, FGD notes, and observation check dates. The data obtained are analyzed and interpreted based on the specified categories. The results showed that: 1) Teacher readiness for learning tools in the components a) Core Competencies (CC) and Basic Competencies (BC) analysis of 45.31%, b) Program mapping of 38.37%, learning plan preparation of 39.45% and c) Learning evaluation of 36.78%; 2) The quality of lesson plan (LP) the science lesson plan analysis instrument (SLPAI) based is divided into two groups. The category "Quality" in the instructional program and instructional plan aspects, and the category "Moderate" in the instructional media and assessment and others aspects; and 3) The difficulty of learning device components, including authentic assessment, use of methods, literacy approaches, and lesson planning. The implementation of training, mentoring, and supervision programs are adjusted to the experience of vocational teachers taking into account the teacher's involvement in the implementation of the curriculum, age, and school readiness.
Volume: 10
Issue: 1
Page: 345-354
Publish at: 2021-03-01

Fast learning neural network based on texture for Arabic calligraphy identification

10.11591/ijeecs.v21.i3.pp1794-1799
Ahmed Kawther Hussein
Arabic calligraphy is considered a sort of Arabic writing art where letters in Arabic can be written in various curvy or segments styles. The efforts of automating the identification of Arabic calligraphy by using artificial intelligence were less comparing with other languages. Hence, this article proposes using four types of features and a single hidden layer neural network for training on Arabic calligraphy and predicting the type of calligraphy that is used. For neural networks, we compared the case of non-connected input and output layers in extreme learning machine ELM and the case of connected input-output layers in FLN. The prediction accuracy of fast learning machine FLN was superior comparing ELM that showed a variation in the obtained accuracy. 
Volume: 21
Issue: 3
Page: 1794-1799
Publish at: 2021-03-01

An accurate technique for supervising distance relays during power swing

10.11591/ijeecs.v21.i3.pp1279-1290
Loai Mohamed Ali El-Sayed , Doaa Khalil Ibrahim , Mahmoud Ibrahim Gilany , Aboul’Fotouh El’Gharably
Power swing is a power system transient phenomenon that arises due to several reasons including line switching, line outage, sudden increment or decrement in load, faults, etc. Unnecessary tripping during power swing and unnecessary blocking for faults occur during power swing result in distance relay maloperation. Several cascaded outages and major worldwide blackouts have occurred due to maloperation of distance relays. This paper proposes a technique for supervising distance relays during power swing. The proposed online technique discriminates real faults and power swing accurately. It relies on constructing a locus diagram for the current and voltage differences (∆I-∆V) between the two ends of the protected line. The locus is estimated at every power frequency cycle to continuously monitor the state of the line by utilizing the synchrophasor measurements at the sending and receiving ends of the line. The proposed technique is tested for two-area, four-machine power system under faults at different locations of zone-1 and zone-2 regions of distance relays, fault resistances, fault inception angles and slip frequencies using MATLAB software. The simulation results proved the superior improvement of distance relay performance for handling power swing blocking and unblocking actions.
Volume: 21
Issue: 3
Page: 1279-1290
Publish at: 2021-03-01

Design and performance evaluation of a PV interface system based on inductive power transfer

10.11591/ijpeds.v12.i1.pp364-373
Ahmed Ragab , Mostafa I. Marei , Mohamed Mokhtar , Ahmed Abdelsattar
This paper presents a photovoltaic (PV) based battery charger utilizing a wireless power transfer (WPT) interface system. The double-sided inductor-capacitor-capacitor (LCC) compensation network is utilized for the inductive power transfer (IPT) system. Because of nonlinear characteristics of the PV, the maximum power point tracking (MPPT) is achieved by controlling the phase displacement angle or the pulse width of the quasi-square pulse inverter connected to the transmitting coil of the IPT system. As a result, the power transferred to the secondary-side, which is connected to a battery bank, is regulated. The IPT-based PV interface system is designed to achieve zero voltage switching (ZVS) in the primary side at rated conditions to minimize the switching loss. Extensive simulation studies are carried out using EMTDC/PSCAD software to investigate the dynamic performance of the proposed IPT-based PV interface system.
Volume: 12
Issue: 1
Page: 364-373
Publish at: 2021-03-01

Impact of the hybrid reactive power compensator on the power grid used a fuzzy PI regulator

10.11591/ijpeds.v12.i1.pp170-182
Abdelkader Rahmouni
The work presented in this article is a contribution to the problem of controlling reactive powers and voltages in an electrical network. Among these control tools, the static reactive power compensator (SVC) was chosen because of its simplicity of control. SVC is one of the Alternative Flexible Current Transmission Systems (FACTS) devices which help to solve the problems encountered in the operation of electrical networks, either on the distribution side or on the transport side. To increase its compensation efficiency in the face of harmonic currents which cause voltage distortion, we have introduced a three-phase harmonic filter. This new hybrid SVC is used to control the reactive power, the voltage and in addition to reduce the voltage distortion and the correction of the power factor in the electrical energy transport network. In order to improve its efficiency, two voltage regulation systems have been chosen in the control system for this compensator, the fuzzy PI regulator and the PIP regulator.
Volume: 12
Issue: 1
Page: 170-182
Publish at: 2021-03-01

Reactive power sharing among distributed generators in a microgrid by using virtual current

10.11591/ijpeds.v12.i1.pp99-111
Eder A. Molina-Viloria , John Edwin Candelo Becerra , Fredy Edimer Hoyos Velasco
This paper presents a new autonomous effective power distribution control strategy for three-phase parallel inverters. The proposal uses a controller that can provide the system with accurate power sharing among distributed generators installed in the microgrid once some load variations are presented in the network. The methodology uses a virtual current loop introduced into the current controller of the inverter to optimize the output signal, which goes directly to the PWM. This virtual current is obtained by using a virtual impedance loop. Furthermore, a small-signal model of the system is used to check stability of the proposed control strategy, which was developed for island mode operation of the microgrid. Simulations were performed for a microgrid with two generators and a load with five households and implemented in MATLAB/Simulink software. The results show that the model provides a wide margin of stability and a rapid response when electrical loads change, thus fulfilling the reactive power sharing among generators. The proposed method shows a large margin of stability and a rapid transient response of the system.
Volume: 12
Issue: 1
Page: 99-111
Publish at: 2021-03-01

Simulation and manufacturing of modified circular monopole microstrip antenna for UWB applications

10.11591/ijaas.v10.i1.pp70-78
Bilal S. Taha , Hamzah M. Marhoon
Ultra-wideband (UWB) technology is one of the most promising wireless communication solutions to be developed quickly because of the high-speed data, wide bandwidth and excellent immunity to multipath interference. In this work, the compact design of a modified circular monopole microstrip antenna is simulated and manufactured for the UWB applications. The simulation process of the proposed antenna was done based on the finite integration of the computer simulation technology (CST) microwave studio (MWS). The proposed antenna comprises a copper radiating patch, Roger’s Kappa-438 substrate, and a single stub act as a reflector. The simulation results showed a reasonable agreement with the results of the measurement and good performance was achieved in the range from 1.8 to 10 GHz with VSWR less than 2.0.
Volume: 10
Issue: 1
Page: 70-78
Publish at: 2021-03-01

Development of an inventory management system using association rule

10.11591/ijeecs.v21.i3.pp1868-1876
Tinuke Omolewa Oladele , Roseline Oluwaseun Ogundokun , Adekanmi Adeyinka Adegun , Emmanuel Abidemi Adeniyi , Ayobami Tayo Ajanaku
Stores today still make use of manual approaches to keeping inventory which could be cumbersome. Having a computerized inventory system would make inventory management more efficient and effective. In this chapter, an Inventory Management System using Association Rule was developed which will ensure proper record keeping and keep items in stocks updated. ANGULARJS, a JavaScript framework, was used for the implementation of the system, PHP (hypertext pre-processor) was used for the backend of the system development as well as the database management, HTML was used alongside CSS for the system interface design and NoSQL database was the database used for this research. In conclusion, a computerized inventory system that had been improved using the Association Rule method was the resulting product useful for creating transactions, updating items in stock, record keeping, generating reports for decision making, and lastly, the system will make the stores more effective.
Volume: 21
Issue: 3
Page: 1868-1876
Publish at: 2021-03-01

Novel method for calculating installed capacity of stand-alone renewable energy systems

10.11591/ijeecs.v21.i3.pp1256-1262
Tang-Tin Dao , Q. S. Vu , Van-Duc Phan , Minh Tran
The use of new energy sources to replace traditional energy sources is the worldwide interest based on its irrefutable advantages, especially in regions where supply systems Power supply cannot reach. The devices installed capacity has a significant effect on the economy as well as on system operation. In this paper, formulate and solve the problem of optimizing installed capacity for devices (generators, charge controllers, storage, inverters) that are used in independent renewable energy systems. In illustrating this method of calculation, we apply it on a standalone system, i.e., it is not connected to the power supply grid.
Volume: 21
Issue: 3
Page: 1256-1262
Publish at: 2021-03-01

Experimentally evaluating electrical outputs of a PV-T system in Jordan

10.11591/ijpeds.v12.i1.pp421-430
Issa Etier , Salem Nijmeh , Mohammed Shdiefat , Omar Al-Obaidy
This experimental work is looking at the properties of photovoltaic/thermal (PV-T) system, which had designed to increase the output power of the PV panel for the climate of Zarqa, Jordan. Operating temperature of the PV module has a significant impact on the performance of the PV module. However, most of the radiation energy absorbed by the PV panel is converted into heat, which is normally lost and provides no value. In order to decrease the operating temperature of the PV panel, a water cooling system with a control system had designed. Experimentally, when the PV module was operating under active water-cooling condition using the backside cooling technique, the temperature dropped significantly, which led to an increase in the electrical efficiency of solar cells by 6.86%.
Volume: 12
Issue: 1
Page: 421-430
Publish at: 2021-03-01

Study of the operation of the output filter of a single-phase series active power filter

10.11591/ijpeds.v12.i1.pp304-313
Mihail Antchev , Vanjo Gourgoulitsov , Hristo Antchev
In the article is presented a single-phase series active power filter (SFSAPF) designed to compensate the total harmonic distortion (THD) factor of the supply network voltage. Particular attention is paid to the work of the output capacitor of the passive filter, and dependencies for the design of the filter at hysteresis voltage control are presented. The value of the higher harmonics of the current through the filter capacitor is determined. A mathematical relationship between the voltage ripple of the capacitor, its value and the switching frequency is derived. As a result of the advanced research a methodology for designing the output filter of a single-phase serial active power filter has been proposed. The results from computer simulation and experiment are also given.
Volume: 12
Issue: 1
Page: 304-313
Publish at: 2021-03-01

The use of reflective practice towards achieving effective English language teaching at primary schools

10.11591/ijere.v10i1.20956
Siti Noor Aneeis Hashim , Nurahimah Mohd Yusoff
The purpose of this study was to explore the use of reflective practice by English language teachers in providing effective English language teaching in primary school classrooms. This qualitative case study involving six in-service English language teachers who were selected based on purposive sampling. The data in this study were collected using teachers’ reflection logs and a series of semi-structured interviews with the English language teachers. Thematic analysis was used to identify emerging themes based on the codes gathered from the interviews and teachers’ reflections logs. The results showed that the English language teachers used reflective practice erstwhile in preparing and providing effective English language teaching for the students. They reviewed what has been accomplished and identify constructive guidelines to follow to succeed in the future teaching. They have also been doing variations of changes in teaching based on reflecting on the quality of instruction, levels of instruction, using incentive to motivate the students and managing time equally in teaching and learning process to help the children in learning English language. Since there is no clear guideline for teachers who use reflective practice in their classes, this study provided some insights on the preparations and the use of reflective practice as part of their teaching and learning process.
Volume: 10
Issue: 1
Page: 364-374
Publish at: 2021-03-01

State feedback control of advanced static var compensator using a five-level NPC inverter topology

10.11591/ijpeds.v12.i1.pp345-355
Mansour Benyamina , Ali Tahri , Abdelkader Boukortt
This paper deals with the modeling and control of an advanced static var compensator (ASVC) using a five-level neutral point-clamped (NPC) voltage source inverter (VSI). The nonlinear state space model of the five-level ASVC is obtained from the d-q axis frame. The effectiveness of this compensator highly depends on the choice of the control strategy. The proposed state feedback control (SFC) technique is applied to adjust the ASVC Var flow with the AC transmission network and achieve DC voltage capacitor balance. The dynamic performance of the ASVC based SFC controller is evaluated under several operating conditions. The simulation results demonstrate that the proposed SFC control strategy is highly robust compared to the conventional Proportional-Integral (PI) control.
Volume: 12
Issue: 1
Page: 345-355
Publish at: 2021-03-01

Knowledge, precautionary actions, and perceived risk of COVID-19 among Indonesian people

10.11591/ijphs.v10i1.20589
Ratih Oktri Nanda , Lolita Lolita , Wiwik Indayati , Ivong Rusdiyanti , Azis Ikhsanudin , Silvia Mareti
Novel coronavirus was first identified in China in December 2019, causing several cases of the new type of pneumonia. The exported cases were found in other countries, including countries in the Southeast Asia region. At the same time, no cases were confirmed in Indonesia. We aimed to assess COVID-19 related knowledge, precautionary actions, and perceived risk among general Indonesian population when there were no confirmed cases in Indonesia. This study was a descriptive cross-sectional study involving 382 participants aged 17 years and above residing in Indonesia. The data was collected through the online questionnaire from February 19th to February 29th 2020. The average score of COVID-19 related knowledge was 88.0%, whereas 83.8% of the participants had a high level of knowledge. The average score of taking precautionary actions was 77.4% and 65.7% had a high level of performance. In terms of the perceived risk of COVID-19, only 11.3% of the participants perceived themselves likely to acquire COVID-19 when compared with other diseases or accidents. The perceived risk of COVID-19 was significantly associated with precautionary action (p<0.05). Perceived risk of COVID-19 was at a low level when there were no confirmed cases. Effective strategies of risk communication are needed to improve precautionary actions to prevent COVID-19.
Volume: 10
Issue: 1
Page: 8-15
Publish at: 2021-03-01
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