Design and implementation of a wind turbine emulator using an induction motor and direct current machine

The study deals with the application details and validation of a wind turbine emulator (WTE) consisting of a user interface, 1.5kW squirrel-cage induction motor (IM) and separately excited direct current machine (DCM). To this end, an induction motor and direct current machine are mechanically coupled to behave like wind turbine. Thus, by controlling the asynchronous motor over wind data, the shaft of the asynchronous motor rotates like the high turbine shaft of the wind turbine and emulates the wind turbine in the laboratory environment. The user interface includes 12 commercial wind turbines with similar characteristics. The user selects the wind data for a day, then selects the wind turbine and operates the system. The system generates reference speed information in accordance with the user's preferences. The WTE calculations are performed on a PC and 32 bit ARM cortex board, both connected on UART. The generated speed information is applied to the frequency converter via the PI control technique and the induction motor is driven according to the reference speed. The purpose of the study is the hardware implementation of a wind energy conversion system for control and online monitoring in a laboratory environment. The system will allow testing various wind data and performing efficiency analyzes at any time and will enable the testing of small-scale power converters for wind power systems

Rapid control prototyping based on 32-Bit ARM Cortex-M3 microcontroller for photovoltaic MPPT algorithms

Since the beginning of the war in Syria, most of the electricity infrastructure has been destroyed, leaving millions with unreliable energy. Syrians have encountered high electricity production costs and environmental damage costs resulting from the utilization of fossil fuels. Similarly, Syria has abundant solar energy can be exploited to meet its electrical power needs. However, because of a lack of expertise in solar energy conversion and the high cost of smart technology, Syrians have typically used photovoltaic systems in primitive ways, in which the efficiency of solar energy conversion is low. There is, therefore, a need for inexpensive, easy-to-implement, yet highly efficient and high performing solutions. Using the STMicroelectronics 32-bit ARM as a maximum power point tracking (MPPT) controller offers a potential solution to the problem of low conversion efficiency in standalone solar systems. In this study, using Matlab-Simulink and STMicrelectronics-32 bit ARM board, simulation and practical test is set up to evaluate the performance of the Perturbation & Observation, Incremental Conductance and Fuzzy Logic MPPT algorithms, in order to determine the most appropriate algorithm to use in small scale solar energy systems. Therefore, one main objective of this study is to explore rapid control prototyping tools for saving time and effort to the experts in the implementation process of the proposed systems. The results indicate the effectiveness of Fuzzy logic algorithm to draw more energy, decrease oscillation and provide a fast response under variable weather conditions. Furthermore, the three algorithms were able to find and track MPP

Şebekeden bağımsız fv sistemde maksimum güç noktası takip algoritmalarının değişken hava şartları altında karşılaştırmalı analizi

Güneş enerjisi en uygun alternatif enerji kaynağıdır; buna ek olarak güneş enerjisi teknolojilerinin uygulanması, elektrik enerjisi taleplerini güvenceye almanın yanı sıra çevre kirliliği ve elektrik üretim maliyetlerini de azaltabilir. Bu çalışmada, maksimum güç noktası takip (MGNT) sistemlerinde kullanılan üç algoritmanın değerlendirilmesi ele alınmaktadır. Bunlar sırası ile Değiştir ve Gözetle (D&G), Artımlı İletkenlik (Aİ) ve Bulanık Mantık (BM) tabanlı algoritmalardır. Bu algoritmalar basitliği ve gerçekleştirme kolaylığı nedeniyle MGNT'de en çok kullanılanlar olarak kabul edilirler. Algoritmalar Matlab/Simulink ortamında tasarlanmış ve üç algoritmanın matematik modelleri çeşitli hava koşullarında test edilmiştir. Benzetimler sonunda bu üç algoritma içerisinden bulanık mantık algoritmasının diğerlerine oranla daha fazla enerji sağlayabildiği, daha az salınım yaptığı ve değişken hava koşulları altında daha hızlı yanıt verdiği gözlenmiştir

Görüntü işleme destekli paralel robot kontrolü

GÖRÜNTÜ İŞLEME DESTEKLİ PARALEL ROBOT KONTROLÜ Bu çalışmada görüntü işleme desteği ile Paralel robot kontrolü yapılmıştır. Kameradan alınan görüntü işlenerek; paralel robotun, pozisyonu değişen bir parçayı farklı konumlarda tutması ve istiflemesi amaçlanmıştır. Endüstriyel uygulamalarda, genellikle yüksek hızlı kameralar tercih edilmektedir. Bu uygulamada ekonomik olması bakımından ve prototip özelliği taşıması bakımından, bilgisayara USB (Universal Serial Bus) üzerinden bağlanabilen, 800x600 piksel çözünürlüğe sahip saniyede 30 poz çekebilen basit bir web kamera kullanılmıştır. USB kameradan alınan görüntü NI Labview ve NI Vision Builder Programları üzerinde yapılan görüntü işleme yazılımıyla işlenmektedir. Hazırlanan görüntü işleme programı sayesinde görüntüsü alınan iş parçasının pozisyonu algılanmaktadır. Algılanan pozisyon bilgisi (x,y,z kordinatları), NI labview üzerinde hazırlanmış, ileri kinematik modele aktarılmaktadır. İleri kinematik sayesinde paralel robotun, istenen konuma gitmesi için gerekli eksen açıları hesaplanmaktadır. Labview’de hesaplanan açı değerleri PC üzerinde bir dosyaya kayıt edilmektedir. Sonrasında; bu uygulama için seçilmiş ABB IRB360 3kg taşıma kapasiteli, 1130mm erişime sahip bir paralel robot, LAN haberleşme protokolü üzerinden, PC üzerinde kaydedilmiş açı bilgilerine ulaşmaktadır. Açı bilgileri, ABB Rapid Programlama diliyle yazılmış robot programı sayesinde belirlenen değişkenlere aktarılmaktadır. Sonrasında robot programındaki senaryoya göre; robotumuz algılanan iş parçasını konveyör üzerinden vakum ile tutup, diğer konveyör üzerinde istiflemektedir. Aralık, 2010 Ahmet KULAKSIZ ABSTRACT CONTROL OF A PARALLEL ROBOT VIA IMAGE PROCESSING In this study, control of a parallel robot is accomplished using means of image processing. The control of a parallel robot to hold workparts, whose positions are not fixed, in different positions and stack them is done by processing images which has been acquired from a camera. Usually high-speed cameras are used in industrial applications. Considering the economic grounds of the study, for the protype an 800x600 pixel USB webcam which can take up to 30 shoots a second is used. The images acquired from the USB camera is processed to obtain the workpart’s position in a image processing software which is build using NI Labview and NI Vision Builder softwares. Obtained position info (x, y, z coordinates) is transfered to Forward Kinematic Model which is also build in NI Labview. Required axis angles to move the parallel robot to a desired position is calculated thanks to Forward Kinematic. The angle values which is calculated in Labview is saved in a document on the PC. Afterwards, parallel robot ABB IRB360, which has an accessibility range of 1130mm and able to lifts up to 3 kg, acquires this document using a LAN communication protocol. Angle values transferred to established variables using a Robot Software which is written in ABB Rapid Programming Language. Finally, according to the scenario in the Robot Software, the parallel robot holds the workpart from a conveyer by vacuum handler and stacks it on another conveyor. December, 2010 Ahmet KULAKSI

GA-BASED ENERGY MANAGEMENT OPTIMIZATION FOR GRID-CONNECTED PHOTOVOLTAIC SYSTEM WITHOUT BATTERY STORAGE

This paper presents genetic algorithm (GA) based optimization of energy management for grid connected photovoltaic (PV) systems without battery storage. The major objective of this work is to minimize energy cost by maximizing objective function of GA considering both energy consumption and generation. In objective function calculation, PV module output power obtained by model of PV modules and previous power recordings from the PV system were employed. In the system, some electrical appliances and lights are in the energy consumption side and photovoltaic energy source connected to the grid is in the energy generation side. A simulation study was implemented to obtain energy cost savings using GA optimization in a commercial building. Due to the cost of the batteries, PV system is implemented without battery storage. Therefore, by adapting fluctuating PV energy generation with the time-flexible loads, an effort was aimed to develop a smart-grid strategy

Performance evaluation of P&O, IC and FL algorithms used in maximum power point tracking systems

With the rapid increase of the requirement of electricity demand throughout the world, renewable energy resources (RERs) particularly solar photovoltaic (PV) is a viable alternative to mitigate the global energy crisis. With the advantages of being inexhaustible, abundant, and clean, PV is considered as one of the most useful RER. Besides, the power efficiency of Solar PV is highly affected by variations of solar irradiance and temperature of the solar cells. Hence, the Maximum Power Point Tracking (MPPT) controller is used to control the switching duty cycle of the power converters which ultimately maximize the output power of the PV array. In this paper, a case study of 240-kW solar PV array is performed in MATLAB/Simulink environment. Simulation is performed on ‘SunPower SPR-400E-WHT-D’ PV array which is comprised of 88 parallel strings and 7 series connected modules per string. The impact of variable weather conditions (irradiance and temperature) is analysed. Moreover, the 240-kW PV array is connected to 20 kV grid using boost converter and Voltage Source Converter (VSC). In this way, the inverted AC output power is coupled with the AC grid. This bidirectional output power with unity power factor can be utilized by industrial/commercial consumers to fulfil their energy demands. In this study, the results are presented to prove that the maximum power fluctuations during rapid weather changing conditions can be reduced and a collaboration in the installation of PV system can be provided

Koç spermasının çözüm sonu kalitesi üzerine farklı sulandırıcıların ve myo-inositolün etkileri

Bu çalışma koç spermasının çözüm sonu kalitesi, lipit peroksidasyonu ve antioksidan aktiviteleri üzerine farklı sulandırıcıların ve inositolün etkilerini değerlendirmek amacıyla yapıldı. Sperma 4 baş Karayaka koçundan suni vajen yardımıyla haftada üç kez alındı. Alınan sperma örneklerinden normospermi özellik gösterenler birleştirildi. Birleştirilen sperma örnekleri iki farklı dozda myo-inositol (5, 10 mM) içeren ve içermeyen (kontrol) üç farklı sulandırıcı (tris, yağsız süt tozu, sodyum sitrat) ile sulandırıldı. Örnekler dokuz ayrı çalışma grubuna ayrıldı: T-5I, T-10I, T (kontrol); M-5I, M-10I, M (kontrol); Na-5I, Na-10I, NaC (kontrol) sulandırılmış sperma içeren payetler 4°C’de 2 saat ekilibre edildi, sıvı azot buharında (-120°C’da 15 dakika) donduruldu ve sıvı azot (-196°C) içinde saklandı. Dondurulmuş spermalar su banyosunda 37°C’de 30 saniyede çözdürüldü. Sulandırıcılara eklenenen myo-inositol mikroskopik sperm ve oksidatif stres parametelerine önemli bir etkiye neden olmadı (P>0.05). T ve M sulandırıcıları, NaC sulandırıcısına göre donma-çözünme sonrası spermatozoon motilitesinde (%50.00±2.24% ve 55.00±3.42) ve HOS testte (%49.00±3.32% and 48.17±2.9) daha yüksek oranlar verdi (P0.05). MDA seviyesi T sulandırıcısında (1.22±0.07 nmol/ml), M ve NaC sulandırıcılarına göre daha düşük bulundu (P<0.05). GSH ve GSH-PX aktiviteleri için, T ve NaC sulandırıcıları M sulandırıcısına göre daha yüksek değerler verdi (P<0.01).The study was conducted to evaluate the eff ects of diff erent extenders and inositol additions on post-thaw semen quality, lipid peroxidation (LPO) and antioxidant activities. Semen was collected from four Karayaka rams from by artifi cial vagina three times a week. Semen samples showing normospermy quality were pooled. The pooled semen samples were extended in three extenders (Tris, T-, skimmed milk, M- and sodium citrate, NaC) with myo-inositol at two diff erent doses (5 mM, 10 mM) and no antioxidant (control). Nine experimental groups were assigned as follows: T-5I, T-10I, T (control); M-5I, M-10I, M (control); Na-5I, Na-10I, NaC (control). Straws containing extended semen were equilibrated at 4&deg;C for 2 h, frozen in vapor of (15 min at -120&deg;C) liquid nitrogen and stored in liquid nitrogen. Frozen semen was thawed in a water bath at 37&deg;C for 30 seconds. The use of all the extenders supplemented with diff erent doses of myo-inositol did not lead to any significant improvement in microscopic sperm and oxidative stress parameters (P&gt;0.05). Extenders of T and M resulted in higher sperm motility (50.00&plusmn;2.24% and 55.00&plusmn;0.42%) and HOST (49.00 3.32% and 48.17&plusmn;2.97%) rates, compared to NaC (37.00&plusmn;3.74% and 31.80&plusmn;2.96%, P&lt;0.01), following the freeze/thawing process. Extenders supplementated with myo-inositol not significantly aff ect malondialdehyde (MDA) levels and activities of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and glutathione peroxidase (GSH-PX) in comparison to the control groups (P&gt;0.05), except for MDA level of T extender containing 10 mM inositol. MDA level was found lower (1.22&plusmn;0.07 nmol/ml) in T than those of the M and NaC (P&lt;0.05). For GSH and GSH-PX activities, T and NaC gave the higher values, compared to M, following the freeze/thawing process (P&lt;0.01)

Consensus and diversity in the management of varicocele for male infertility: Results of a global practice survey and comparison with guidelines and recommendations

Purpose: Varicocele is a common problem among infertile men. Varicocele repair (VR) is frequently performed to improve semen parameters and the chances of pregnancy. However, there is a lack of consensus about the diagnosis, indications for VR and its outcomes. The aim of this study was to explore global practice patterns on the management of varicocele in the context of male infertility. Materials and Methods: Sixty practicing urologists/andrologists from 23 countries contributed 382 multiple-choice-questions pertaining to varicocele management. These were condensed into an online questionnaire that was forwarded to clinicians involved in male infertility management through direct invitation. The results were analyzed for disagreement and agreement in practice patterns and, compared with the latest guidelines of international professional societies (American Urological Association [AUA], American Society for Reproductive Medicine [ASRM], and European Association of Urology [EAU]), and with evidence emerging from recent systematic reviews and meta-analyses. Additionally, an expert opinion on each topic was provided based on the consensus of 16 experts in the field. Results: The questionnaire was answered by 574 clinicians from 59 countries. The majority of respondents were urologists/uro-andrologists. A wide diversity of opinion was seen in every aspect of varicocele diagnosis, indications for repair, choice of technique, management of sub-clinical varicocele and the role of VR in azoospermia. A significant proportion of the responses were at odds with the recommendations of AUA, ASRM, and EAU. A large number of clinical situations were identified where no guidelines are available. Conclusions: This study is the largest global survey performed to date on the clinical management of varicocele for male infertility. It demonstrates: 1) a wide disagreement in the approach to varicocele management, 2) large gaps in the clinical practice guidelines from professional societies, and 3) the need for further studies on several aspects of varicocele management in infertile men