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

Seasonal Variation of the Nutrient Contents of Sarcopoterium spinosum (L.) Spach

The research was conducted to find out the feeding potential of Sarcopoterium spinosum (L.) Spach, commonly found in Mediterranean climate dominated areas and also have an important place in rangeland livestock farming as well as in erosion of these areas. The study was carried out in Yıldız Koyu of Gökçeada Island in 2013. The nutrient contents of plant were determined seasonally (winter, summer, spring and fall) as well as in different organs (stalk and leaf) of the plant. Total of 10 plants were taken during each sampling period. Only the crude protein and ADF contents of plant leaf had found statistically important in terms of season, but there were not any significant importance in respect to other characteristics of the plant. The leaf and stalk ratios were changed between 37.57% (fall)–42.38% (winter) and 57.62% (winter)–62.49% (fall), respectively. Highest leaf/stalk ratio (0.74) has been observed in winter while the least (0.60) in fall. Average crude protein (6.39%), ash (9.66%) and fat (6.33–7.60%) of leaves were found more as compared to the crude protein (3.81%), ash (4.95%) and fat (4.37–5.80%) of stalk. On the other hand, NDF (36.19–43.41%), ADF (22.31–27.54%) and ADL (9.50–13.35%) of leaves were found less as compared to stalks. Consequently, Sarcopoterium spinosum has an importance in terms of soil protection and shrub formation into the degraded parts of Mediterranean flora, also found as a feed source for animals. However, supplementary feed should be given to the animals grazing in these areas for overcoming their poor performances

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

Evaluation of Total Roughage Production and its Sufficiency for Livestock in Turkey

In this study, total roughage production and its sufficiency for farm animals in Turkey was evaluated. Because of insufficient production, feed prices are relatively high and fluctuating in Turkey. It was estimated that, the total 40 363 210 tonnes of roughages production in Turkey was supplied by meadows and pastures (13 164 210 tonnes), shrublands (11 267 000 tonnes) and forage crops production (15 932 000 tonnes). In addition, total straw and stubble production was estimated as 31 074 800 tonnes for animal feed, indicating that half of the total roughages production in Turkey came from straw and stubble production. In Turkey, the large and small ruminant stock is composed of a total of 17 066 900 animal units and in order to meet only the maintenance requirements of these animals via roughage, 77 867 731 tons of roughage is needed in 2019. Considering the daily dry roughage requirement as 12.5 kg (approximately 2.5 percent of total 500 kg live weight), deficiency of daily feed amount was estimated as 1.032 kg per animal unit and a total of 6 429 720 tonnes in 2019 in Turkey. If shrublands, straw and stubble production is neglected or removed from the calculation, then total deficiency reaches at 48 771 521 tonnes year-1 (62.63% of the total feed requirement). For a rational animal feeding, not only the maintenance requirements of the animals but also, in addition to their maintenance requirements, at least 5-7 kg of milk production requires meeting from quality roughages. In this case, it is clear that the need for roughage will increase more. In Turkey, suffering from roughage shortage that adversely affecting production obtained from small and large ruminants, high quality forage production should be, at least, doubled by using every possible resource including natural rangelands, fallows, and cultivated lands effectively without compromising soil conservation and feed costs principles

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

Variation of Nutritional Values in Leaves and Stalks of Different Maize Genotypes Having High Protein and High Oil During Vegetation

AbstractThis study was aimed to determine the variations into the nutrient contents found different plant parts of maize genotypes that containing high level of oil and protein at their different vegetative stages. In this study, six different maize genotypes were used as plant materials that have been generated by crossing of two special types of maize namely, IHO and IHP with two normal elite inbred lines (B73 and Mo17). Field trials have been conducted by using randomized complete block design along with three replications in the region of northwest of Turkey. Samplings were designed in accordance to plant sowing date and they were taken from the field at 40th, 60th, 82nd, 100th and 122nd days after sowing. Neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), crude ash (CA), organic matter digestibility (OMD) and dry matter digestibility (DMD) have been investigated during this study work. The results of this research showed that the significant differences were found among genotypes and some sorts of significant variations have been observed into the cell wall components. Genotypes, having high level of protein in their stalks, have been found superior in terms of nutrient content while the genotypes, having high level of oil in their leaves, were found best for nutrient values

Annual changes in biomass amount and feeding potential of shrubby rangelands in maquis formation

Background This study evaluated the extent to which the endemic herbaceous and woody species of shrubby rangelands met the roughage needs of grazing animals throughout the year. Methods The biomass, botanical composition, and quality of hay were investigated in the shrubby rangelands in Paşaköy of the Ayvacık districts in Çanakkale over the course of a year. Plant samples were taken from the herbaceous species monthly and from the grazing parts of the shrubs in May and November. Results The total amount of biomass (hay + shrub) in the rangeland was found to be 30.448 kg/ha. Shrubs made up 18.78% of the rangeland, while the annual species comprised 54.96%, and perennial herbs covered 26.26% of the total biomass. Crude protein (CP) ratios of herbaceous species decreased continuously from March (13.58%) to September (6.73%), and then increased. A similar change was also seen in pure ash (PA) ratios. The CP ratios in the shrub species were high in spring and decreased in autumn and there was an irregular variation in PA rates. Oak had the highest PA ratio during the spring, while thuja had the highest ratio in autumn, and Juniperus oxycedrus during the winter months. In herbaceous species, cell wall components (NDF, ADF, and ADL) reached their highest levels in summer and decreased in spring and winter. However, in shrubs, these components varied according to the species and were generally lowest in spring and then increased in autumn and winter. Here, it was determined that year-round grazing is a suitable grazing system in the shrubby rangelands of the Mediterranean zone, and animals are able to find fresh forage in the rangelands due to the presence of shrubs. However, since the contribution of shrubs to the total forage production is low, additional roughage should be provided, except in the spring when the production and quality of hay increase. These practices may contribute to better livestock management

Türkiye’ye Bowling'in gelişi ve gelişimi

Ankara : İhsan Doğramacı Bilkent Üniversitesi İktisadi, İdari ve Sosyal Bilimler Fakültesi, Tarih Bölümü, 2015.This work is a student project of the The Department of History, Faculty of Economics, Administrative and Social Sciences, İhsan Doğramacı Bilkent University.by Özer, Abdürrahim

Effects of Prickly Burnet (Sarcopoterium spinosum (L.) Spach.) Control and Sheep Grazing on Hay Yield and Quality on Gökçeada Island, Turkey

(1) Background: The effects of prickly burnet (Sarcopoterium spinosum) control measures (pulling out, burning and cutting) and grazing on the botanical composition, grazeable dry matter (GDM) yield and nutritional values of rangeland were investigated on Imbros Island (Turkey) in 2010–2013. (2) Methods: The rangeland was grazed by Imbros sheep during the last year of the experiment. About 0.15 ha of rangeland was allocated to each sheep and five sheep were placed in each plot. Grazing was continuous throughout the year. (3) Results: Shrub levels decreased by 50–60% due to pulling out, burning and cutting in the first year and herbaceous species increased. Forbs increased more in the pulled and burnt plots and grasses increased more in the cut plots. In the third year, the shrub level increased to 60–65% and herbaceous species decreased. The decrease in herbaceous species was observed mostly in forbs. Plant cover was mostly (58%) composed of annual species. Development decreased plant cover ratios, but this decrease ceased in the burnt plot in the third year. Grazing also reduced plant cover. Crude protein (CP), NDF, ADF and digestible dry matter (DDM) content did not vary significantly over the experimental period. CP and DDM increased, NDF decreased and ADF did not change in the development plots. Overall, significant differences were not observed in GDM yield and nutritional values due to development efforts (pulling out, burning and cutting). (4) Conclusions: However, cutting is difficult over stony and rough terrain and pulling out creates erosion on sloping surfaces. Therefore, burning is recommended over the entire rangeland and burning or pulling out is recommended over smooth terrain for the temporary control of S. spinosum