1,720,962 research outputs found
Sistem Kendali Daya Maksimum Pembangkit Listrik Tenaga Angin Menggunakan Very Sparse Matrix Converter Berbasis Kecerdasan Buatan
Get PDFPembangkit listrik tenaga angin kurang berkembang di Indonesia, karena kondisi kecepatan angin yang rendah serta kurang ekonomis dibandingkan sumber energi lain. Untuk meningkatkan peran pembangkit listrik tenaga angin di Indonesia perlu dilakukan pengembangan untuk meningkatkan performansi pembangkit. Dalam disertasi ini diusulkan sebuah metode untuk meningkatkan performansi pembangkit listrik tenaga angin yang menggunakan generator tipe Permanent Magnet Synchronous Generator (PMSG).
Peningkatan performansi pembangkit listrik tenaga angin dirancang untuk meningkatkan kualitas daya dan efisiensi pembangkit. Peningkatan kualitas daya dilakukan dengan memilih konverter daya jenis Very Sparse Matrix Converter (VSMC). Konverter ini dipilih karena memiliki keuntungan antara lain tidak menggunakan dc link, dapat menghasilkan gelombang tegangan sinusoidal pada sisi grid dan lebih ekonomis karena jumlah switch aktifnya lebih sedikit dibandingkan matrix konverter lain. Peningkatan efisiensi dirancang dengan mengembangkan sistem kendali daya maksimum atau disebut juga Maximum Power Point Tracking (MPPT), yang terdiri dari kontroller kecepatan dan algoritma MPPT.
Penelitian ini memberikan dua kontribusi, yaitu desain kontroller kecepatan PMSG menggunakan Adaptive Type-2 Fuzzy Sliding Mode Control (AFSMOC) dan desain algoritma MPPT menggunakan metode multiclass Least Squares Support Vector Machine (LS-SVM). Metode AFSMOC dirancang untuk meningkatkan ketahanan Sliding Mode Control (SMC) dalam mengendalikan kecepatan PMSG dengan membuat penguat adaptif pada sliding surface menggunakan Type-2 Fuzzy System (T2FS).
Algoritma MPPT dengan metode LS-SVM dirancang untuk mencari kecepatan referensi pada titik daya maksimum berdasarkan perubahan daya output generator. Kinerja algoritma MPPT ditentukan oleh ukuran step. Algoritma LS-SVM didesain untuk mendapatkan ukuran step yang bervariasi, sehingga dapat mempercepat respon mencapai titik maksimum serta dapat meminimalisir riak kecepatan pada titik maksimum. Algoritma LS-SVM dipilih menggunakan metode RBF kernel dengan encode One vs One dan decode hamming distance. Metode ini dipilih karena lebih akurat dengan overall accuracy 97.19%.
Model pembangkit listrik tenaga angin yang diusulkan menggunakan PMSG 2.5 kW yang terhubung dengan grid 380/220 Volt 50 Hz. Generator digerakan oleh turbin angin horizontal tanpa gearbox dengan jari-jari 2 m dengan koefisien daya maksimum 0.53125 dan Tip Speed Ratio (TSR) optimum 8.09. Model disimulasikan dengan kecepatan angin yang bervariasi melalui simulink dan interface National Intrument Data Acquisition (NIDAQ) USB 6211.
Hasil simulasi menunjukkan bahwa model yang diusulkan memberikan hasil yang lebih baik dibandingkan metode lain. Penggunaan LS-SVM untuk algoritma MPPT telah mampu mereduksi error maksimum koefisien daya dari 1.46% pada algoritma PO menjadi 0.047%. Hal ini menunjukkan bahwa penggunaan LS-SVM telah dapat meningkatkan daya output generator. Penggunaan AFSMOC juga telah mampu meningkatkan ketahanan kontroller kecepatan menghadapi gangguan eksternal. Error maksimum kecepatan dapat direduksi dari 1.27% pada SMC menjadi 0.14% pada kondisi transien. Penggunaan VSMC juga telah dapat meningkatkan kualitas daya pembangkit dengan arus dan tegangan sinusoidal pada grid.
=====================================================================================
Wind power generation system is underdeveloped in Indonesia, due to low wind speed conditions and and less economical than other energy sources. To enhance the role of wind power generation system in Indonesia, the development is necessary to improve its performance. This dissertation proposes a method to increase the performance of grid connected-wind power generation system that use Permanent Magnet Synchronous Generator (PMSG).
Improved performance of wind power generation system is designed to improve the power quality and efficiency. The improvement of power quality is done by choosing Very Sparse Matrix Converter (VSMC) as power converter. This converter is chosen due many advantages such as not using dc-link storage, can produce sinusoidal voltage at grid side and more economical because the number of switches less than other matrix converters. The improvement of efficiency is designed by develop the maximum power control or also known as Maximum Power Point Tracking (MPPT), consisting of the speed control and the MPPT algorithm.
This research study provides two contributions, namely design of the PMSG speed control using Adaptive Type-2 Fuzzy Sliding Mode Control (AFSMOC) method and the design of the MPPT algorithm using multiclass Least Squares Support Vector Machine (LS-SVM) method. The AFSMOC is designed to improve the robustness of Sliding Mode Control (SMC) by creating the adaptive gain in sliding using Type-2 Fuzzy System (T2FS).
MPPT algorithm based on LS-SVM method is designed to tracking the reference speed at maximum power point based on the output power of generator. The performance of MPPT algorithm is determined by the step size. LS-SVM algorithm is designed to obtain the variable step size, so it can accelerate the response reaches a maximum point and minimize the speed ripple at maximum point. LS-SVM algorithm is chosen using RBF kernel with One vs One encode and hamming distance decode. This method was chosen because it is more accurate with overall accuracy 97.19%.
The proposed model using PMSG 2.5 kW are connected to grid 380/220 Volt 50 Hz. The PMSG driven by horizontal wind turbine with blade radius 2 m, maximum power coefficient 0.53125 and optimum Tip Speed Ratio (TSR) 8.09. The model was simulated with varying wind speeds through simulink and National Intrument Data Acquisition (NIDAQ) USB 6211.
The simulation results show that the proposed model gives better results than other methods. The use of LS-SVM for MPPT algorithm has been able to reduce the maximum error of power coefficient from 1.46% in PO algorithm become 0.047%. This result indicate that the use of LS-SVM has been able to increase the generator output power. The use of AFSMOC also been able to increase the robustness of the speed controller against external disturbances. In transient conditions, the maximum error of speed can be reduce from 1.27% in SMC method becomes 0.14% in AFSMOC method. The use of VSMC has also been able to improve the power quality of system with sinusoidal grid voltage and grid current
Kendali Tegangan Konverter Boost Berbasis Proposional Integral (PI)
Get PDFTechnological developments, electronic components and circuits have resulted in a direct voltage supply system that is produced by converting the input DC voltage to another form of DC voltage with a higher output utilizing a boost converter circuit, using a low source voltage where the output voltage can be changed according to user requirements. To anticipate the voltage drop on the output side which is affected by changes in the resistance value of the load and changes in the value of the source voltage, a voltage control is needed that can regulate the output stability of the boost converter. One of the voltage control techniques used is integral proportional controller (PI). This study uses the Ziggler – Nichols oscillation method which is applied to the integral proportional controller (PI) in the boost converter circuit by using the Arduino Mega2650 as a controller circuit which is programmed with Matlab Simulink and a voltage sensor that functions to detect output on the boost converter as well as feedback from the Proportional Integral (PI) controller which will later be compared with the desired setpoint to produce the appropriate Pulse width Modulation (PWM) signal. The test results show that the PI controller works well in accordance with the purpose of adjusting the output voltage on the boost converter. This can be seen in the output of the boost converter which is in accordance with the reference voltage of 15 volts, 20 volts, and 24 volts with an output voltage of 15.36 volts, 20.52 volts, 24.82 volt
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Implementasi Pompa Air Tenaga Surya Menggunakan Inverter Boost Satu Fasa
Get PDFPompa air tenaga surya adalah salah satu alternatif penyediaan air bersih untuk daerah yang belum terjangkau jaringan listrik. Pompa air tenaga surya membutuhkan peralatan yang dapat menaikan tegangan panel surya sesuai dengan rating tegangan motor pompa air dan inverter untuk mengkonversikan tegangan dc panel surya menjadi tegangan ac sesuai dengan tegangan motor pompa air. Paper ini mengusulkan inverter boost satu fasa untuk pompa air tenaga surya yang dapat menaikan sekaligus mengkonversikan tegangan dc menjadi tegangan ac tanpa menggunakan transformator. Modulasi inverter dirancang menggunakan metode Sinusoidal Pulse Width Modulation (SPWM) yang diimplementasikan dengan arduino uno. Pompa air tenaga surya diimplementasikan untuk penyediaan air bersih di Mesjid dengan menggunakan panel surya 300 WP. Hasil pengujian di lapangan menunjukan bahwa pompa air tenaga surya yang diusulkan telah bekerja dengan baik sesuai dengan yang diharapkan. Inverter boost satu fasa yang diusulkan telah dapat mengkonversikan tegangan panel surya sesuai dengan rating tegangan motor pompa air.Pompa air tenaga surya adalah salah satu alternatif penyediaan air bersih untuk daerah yang belum terjangkau jaringan listrik. Pompa air tenaga surya membutuhkan peralatan yang dapat menaikan tegangan panel surya sesuai dengan rating tegangan motor pompa air dan inverter untuk mengkonversikan tegangan dc panel surya menjadi tegangan ac sesuai dengan tegangan motor pompa air. Paper ini mengusulkan inverter boost satu fasa untuk pompa air tenaga surya yang dapat menaikan sekaligus mengkonversikan tegangan dc menjadi tegangan ac tanpa menggunakan transformator. Modulasi inverter dirancang menggunakan metode Sinusoidal Pulse Width Modulation (SPWM) yang diimplementasikan dengan arduino uno. Pompa air tenaga surya diimplementasikan untuk penyediaan air bersih di Mesjid dengan menggunakan panel surya 300 WP. Hasil pengujian di lapangan menunjukan bahwa pompa air tenaga surya yang diusulkan telah bekerja dengan baik sesuai dengan yang diharapkan. Inverter boost satu fasa yang diusulkan telah dapat mengkonversikan tegangan panel surya sesuai dengan rating tegangan motor pompa air
Implementasi Pompa Air Otomatis Tenaga Surya Untuk Rumah Ibadah
Get PDFClean water is one of the most vital needs for a mosque. Clean water is generally taken from wells using electric water pumps. The use of water pumps is often a problem in areas where the electricity network is often off, as happened in the Raya Mosque of Nagari Salareh Aia, Palembayan District, Agam Regency. To overcome this problem, a solar automatic water pump is designed which is equipped with a battery as a backup power supply and one phase inverter to convert the solar panel voltage to alternating voltage according to the voltage of the water pump motor. The water pump automation is designed using a floating switch installed in a water tank. This solar water pump is implemented using a 300 wp solar panel, a 90 Ah battery and a 1200 Watt inverter. This solar water pump is also equipped with a solar charger for charging and discharging batteries. Field test results show that the automatic solar water pump proposed in this service program has been working properly according to the plan
Direct Torque Control Strategy of PMSM Employing Ultra Sparse Matrix Converter
Get PDFMatrix converter is a good choice for Permanent Magnet Synchronous Motor (PMSM) drives, because it has high power density and does not require dc-link energy storage. the disadvantages of conventional matrix converter is using 18 active switches, so it becomes expensive and the modulation method becomes more complicated than back to back converter. To minimize this problem, this paper proposes variable speed drive of PMSM using Ultra Sparse Matrix Converter (USMC) based on Direct Torque Control (DTC) methods. This converter uses only 9 active switches, making it cheaper than conventional matrix converter. DTC is designed based on Space Vector Modulation (SVM) to reduce torque and flux ripples due to the hysteresis control in conventional DTC. The simulation results show that DTC based SVM using USMC effectively controls the rotor speed with low torque and flux ripples
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
