ac dc ac converters used in wind turbine systems

... losses in wind turbine, ρ = air density in kg/m3, A = swept area in m2, Cp =power coefficient of wind turbine, V = wind speed in m/s Mechanical power of wind turbine is directly related to the wind ... maximize its capacity factor, and participate in generating electricity at good costs Many factors have to be considered during manufacturing or installation of wind turbines, i.e., (turbine swept ... speed is determined by power coefficient [9] λ=ωt×r/V (6) where: r = wind turbine rotor radius, V = wind speed, ωt = mechanical angular rotor speed of the wind turbines Initially, wind speed is...

Ngày tải lên: 05/09/2013, 16:10

... coefficient factor Substituting (2) and (3) into (1), the ac output current iac is expressed as, V 2T k iac = dc s sin(ωt ) 2L (4) In practical implementation of an inverter control, a sinusoidal ... operation for this inverter have proved its feasibility for dc -ac conversion in wind turbine applications ACKNOWLEDGMENT The authors wish to thank Natural Sciences and Engineering Research Council ... inverters can accommodate a wide range of input dc voltage for an improved energy output from variable wind turbine resources The input source and the output grid are separated based on flyback...

Ngày tải lên: 03/01/2014, 19:16

... offspring test involves producing a number of offspring from each breeding candidate and placing them in an infected environment The rate of mortality due to infectious diseases in the offspring groups ... taking G × E interactions into account in selection schemes The mechanism behind the G × E interaction is described in Box Chicken genetic resources used in smallholder production systems BOX ... completely during the incubation and brooding phase From a genetic resource point of view, indigenous hens are vital for maintaining a natural source of egg incubation, given that the high-yielding table...

Ngày tải lên: 23/03/2014, 21:20

... are developed in the MATLAB/Simulink® software environment A Wind turbine model The wind turbine extracts the wind aero dynamical power The model of the wind turbine uses several inputs to estimate ... of Wind Turbine Generators during Random Wind Fluctuations’, IEEE Transactions on Power Apparatus and Systems, No June 1981 Z Lubosny Wind Turbine Operation in Electric Power Systems , Springer ... sudden large change in the wind speed occurs, the MPP tracker use predefined turbine characteristics of the MPPT curve as it shown in Fig T12-123 Fig 11 DC voltages at real wind conditions 3 controller...

Ngày tải lên: 03/01/2014, 19:15

... low winds speeds Fig.8: Wind turbine output power with MPPT control method for low wind speed Start Fig and 10 give the wind turbine output power without and with MPPT control method for high wind ... CONTROL METHOD In order to extract the maximum wind power, an analysis was provided to understand the probable displacement of the operating point in the two operating zones of wind turbine Fig 5, ... operating power and the maximum power, in the event of change of the wind speed, the control of the buckboost converter perturbs periodically the operating point of the wind turbine By acquiring...

Ngày tải lên: 03/01/2014, 19:15

... CC,SB CC,SC Core t6 in Minor section Jo t5 in Minor section Jo in Minor section Jo Minor section t4 Major section – km Jo in t3 t2 in Minor section Jo t1 in Minor section Jo Jo in t0 Major section ... material contained herein Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) Parts of this thesis have been published in the following articles: ... XLPE cables and the increasing interest in the environmental impact of OHL has resulted in an increasing interest in the use of underground cables on transmission level In Denmark, the entire 150,...

Ngày tải lên: 26/11/2015, 11:13

... giving instructions), monitoring (listening to the pairs/ groups during the activity and guiding / giving support/ making notes) and winding down (bring the activity to a close and providing ... be the most typical characteristics of CLT 2.2 Teaching speaking skill in CLT 2.2.1 Teaching speaking skill Speaking skill plays a significant role in teaching and learning a foreign language ... classroom speaking time when learners are practicing an intonation contour or trying to pinpoint a certain vowel sound, etc - Intensive: includes any speaking performance that is designed to practice...

Ngày tải lên: 07/11/2012, 14:50

... study lie in both theoretical and practical aspects Theoretically, the study helps to find out linguistic features used in airlines slogans in particular and in our social life in general Practically, ... Language of Airlines’ Advertising Slogans Page 14 Business Advertising Business advertising is often said to be invisible, because unless one is actively involved in some business, he is unlikely ... Advertising Information Advertising information is the principal contents an advertisement wants to disseminate Advertising is a series of planning actions, so the information of advertising should...

Ngày tải lên: 07/11/2012, 14:54

... precise definition of teaching can not be given; A few definitions of teaching are as follows According to Barr (1961), “teaching means many different things, and that the teaching act varies ... Reading in Large Classes 2.14 Pre-Writing Activities 2.15 Teacher Development 17 18 19 20 2.16 Teaching of Poetry 2.17 Steps in Teaching Poem 21 2.18 The Place of Syllabus 23 2.19 Choosing & Integrated ... different teaching methods will be required/ used for teaching a language and teaching physical sciences Even in case of learning a language, the four main skills i.e listening, speaking, reading and...

Ngày tải lên: 10/04/2013, 10:37

... things such as asking for information, looking for jobs, complaining about something, inviting and so on b Language: Writing letters c Stage of teaching: While-writing d Levels: Except the beginners ... Here are some examples used with this technique: Join these pairs of sentences, using the words in brackets: 1.It was raining heavily We went hunting (Although) 2.I had lived in the North for years ... chiefly used to teach the students to write a paragraph or a passage c Stages of teaching: pre-writing (for gathering ideas Independent) d Levels: All levels e Example: Write anything you think will...

Ngày tải lên: 03/06/2013, 01:26

... [Lat.]: situated in the original or natural position “I prefer seeing statues in situ rather than in the confines of a museum.” in vino veritas (in vee'no vare'i-toss) [Lat.]: in wine there is truth ... parentis.” in medias res (in me'-dee-as rays) [Lat.]: in the middle of a sequence of occurences “The film begins in medias res, with a panting, terrified man running through the night.” in situ (in sit'too) ... “Marie Antoinette recommended cake to the hoi polloi.” in loco parentis (in loh'koh pa-ren'tiss) [Lat.]: in the place of a parent “The court appointed a guardian for the children, to serve in loco...

Ngày tải lên: 02/07/2013, 01:25

... ice accretion on the wind turbine blades can be minimized This could reduce the need for de- and anti-icing systems on the wind turbine blades installed in the cold regions Future work must include ... Table Cylinder Cylinder Cylinder DU 40 DU 35 DU 35 DU 30 DU 25 DU 25 DU 21 DU 21 NACA 64618 NACA 64618 NACA 64618 NACA 64618 NACA 64618 NACA 64618 Figure 3D CAD of the NREL MW wind turbine blade, ... rime ice accretion on aerodynamic characteristics of wind turbine blade profiles Wind Engineering, 2010 In press [2] Ronsten, G., Svenska erfarenheter av vindkraft i kallt klimat nedisning, iskast...

Ngày tải lên: 05/09/2013, 14:58

... or criteria of classifying advertising as follows: (1) Basing on medium criterion, advertising types include print advertising (newspaper, magazines), broadcast advertising (radio, television), ... trophy in the world of sailing Its organizers have entrusted once again the vital timing of the races to Omega, a company whose experience in watchmaking and sports timekeeping dates back over ... no advertising.” Another definition of advertising is according to the Investorwords glossary: “Description or presentation of a product, idea, or organization, in order to induce individuals...

Ngày tải lên: 07/09/2013, 14:03

... increased by combined use of fibric acid agents (see below) Nicotinic acid and its derivatives (pyridylcarbinol, xanthinol nicotinate, acipimox) activate endothelial lipoprotein lipase and thereby ... unpleasant experience The statins, lovastatin (L), simvastatin (S), pravastatin (P), fluvastatin (F), cerivastatin, and atorvastatin, inhibit HMG CoA reductase The active group of L, S, P, and ... Cholesterol Bioactivation Active form Extraction of lipophilic lactone Active uptake of anion HO O HO O O H3C O H3C Oral administration CH3 H3C Lovastatin COOH OH F CH3 N CH3 Fluvastatin A Accumulation...

Ngày tải lên: 18/10/2013, 00:15

... vocabulary? h a completed fact 49 cliché Practice Activities n artistically innovative a feud characterized by acts of retaliation 96 – VOCABULARY LIST 5: FOREIGN LANGUAGE TERMS USED IN ENGLISH – Answers ... means lacking social grace or 52 r sophistication, the opposite of the meaning of the words in the group 32 naïve Naïve means simple and innocent, the opposite of the meaning of the words in the ... was coming down with something 92 – VOCABULARY LIST 5: FOREIGN LANGUAGE TERMS USED IN ENGLISH – Words in Context Sentence Completion The following exercise will help you figure out the meaning of...

Ngày tải lên: 25/10/2013, 17:20

... Infinitive present tense -ing form past tense past participle back up & backs up backing up backed up backed up backup back up p.v When you walk backward, you backup When you ... -ing form past tense past participle back off & backs off backing off backed off backed off back off back off p.v When you move away from danger or a person you are arguing or fighting with in ... better back off Tom backed off when he saw that Jake had a gun Infinitive present tense come across -ing form past tense past participle come across & comes across coming across came across come across...

Ngày tải lên: 01/11/2013, 12:20

... Infinitive present tense -ing form past tense past participle back up & backs up backing up backed up backed up backup back up p.v When you walk backward, you backup When you ... from moving, progressing, or flowing normally / sat in that backup for three hours without moving an inch The huge number of Christmas cards and packages caused a backup at the post office backed ... When something is being prevented from moving, progressing, or flowing normally, it is backed up Let's take the train downtown Traffic is always backed up at this time of the morn in a Infinitive...

Ngày tải lên: 01/11/2013, 15:20

... were used to find out the similarities and differences in the important part in finding the result of the research to produce a linguistic features of SAYING verbs used in political documents in ... the Findings and 23 24 these verbs are classified into five different groups, such as asserting, in certain contexts, which help obtain to good results in using these committing, directing, declaring, ... features of SAYING verbs used in political documents in English and purpose of making explicit (which is not the same as stating or Vietnamese describing) what precise action it is that is being performed...

Ngày tải lên: 26/11/2013, 13:19