Search or add a thesis

Advanced Search (Beta)
Home > Ripple Free Torque Operation in Switched Reluctance Motors

Ripple Free Torque Operation in Switched Reluctance Motors

Thesis Info

Access Option

External Link

Author

Saleem, Yasir

Program

PhD

Institute

University of Engineering and Technology

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2008

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2864/1/1275S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727105823

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


This thesis investigates the control of current and torque at different speed of the switched reluctance motor observing the motor constructional properties, mathematical model equations, operating principle and power converter topologies. The switched reluctance motor has gained popularity in industry with the fact that it is simple to construct and suitable for harsh environment. The electromechanical energy conversion is produced from rather simple machine design than as it is done in conventional motors. The other advantages are its rugged construction, low maintenance cost, and ability to operate over a wide speed range at constant power. The merits of switched reluctance motors are marred by the requirement of expensive control and its innate torque ripple issue, which is also a cause of vibration and acoustic noise. Torque ripple is produced from successive excitation of phase currents. The current through phase windings produces magnetic force with tangential and radial components where former component contributes to the average torque production and the latter is the major cause of vibration and acoustic noise in switched reluctance motors. Torque ripple reduction leads to smooth operation, thus it also improves the vibration and acoustic noise. This reduction can be achieved either through better machine design or with superior control techniques. Better machine design involves basic design parameters like number of stator poles, rotor poles and also their shape which is generally determined using detailed magnetic analysis. In this piece of work literature review of both approaches is included but the latter current control approach is adopted for detailed research. This thesis also discusses the split stator winding technique to improve reduction in torque ripple. This is unique strategy to introduce a compensation torque and remarkable reduction in torque ripple. This technique requires the slight change in shape of stator. This technique has ability to eliminate the negative torque generation and also the starting problem in switched reluctance motors. The control techniques deal with the electronic part of complete drive systems. The torque and current are directly related to each other, so the torque control can be implied by current control methods. This dissertation discusses the new current control technique with efficient bipolar power converter for torque ripple mitigation control. This piece of work also elaborates the new unique strategy of split stator winding for torque ripple reduction. In this thesis motor mathematical model is simulated using new control strategy along with two power converter topologies, conventional asymmetric half bridge converter and proposed symmetric full bridge converter. In addition split stator winding technique is simulated with suggested bipolar drive to show the improvement in ripple reduction. The experimental setup is also included in this thesis, where specific motor is operated using complete drive system. The design and implementation of this drive system is discussed in detail. This drive system is capable to perform both conventional and bipolar operations. At the end, practical results and simulated results are acquired and compared. The effect of excitation and de-excitation angles on torque production is observed and simulated. Torque and current relationship is observed to conclude which drive is suitable for smooth torque operation and have better current control at different speeds. The apparent cost difference is also analyzed and it is found that full bridge drive is more suitable for general purpose solution in industry with bearable increase in cost.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

تانیثیت کا نظریاتی پس منظر اور اردو کا نسوانی ادب

ثانیثی  ادب  اور تنقید مخصوص جنسی گروہ کے لیے قلم بند کی جاتی ہے۔ جس کے لکھنے والے اور قاری مخصوص جنسی  گروہ سور رجحان سے وابستہ ہوتے ہیں۔  کیونکی اس جنسی گروہ کا معاشرے میں مخصوص کردار ہوتا ہے۔ 1960 میں یہ روئیے جدید  رنگوں مین  ایک عمرانیاتی  شعور کے ساتھ  ہمارے مطالعوں اور سوچوں کا حصہ بنے۔ثانیثیت {FEMINISM} کے معاشرتی اور ادبی نظریاتی مطالعات میں جنسی تعصّبات کے حوالے سے بہت حساس رہا ہے۔اس کے سکہ بند تصورات پر سوالات بھی اٹھاتی ہے۔ ثانیثی تنقید میں مارکسی، فرائدین، ساختیاتی پس ثانیثی تنقید، رد ثانیثی تنقید، نئی ثانیثی تنقید، نسلی اور مذھبی ثانیثیت تناظر میں اپنی اپنی تعبیرات اور تفاسیر بیان کی گئی ہیں۔ اس کو عورت کی مزاحمت اور احتجاج کا نظریہ بھی کہا جاتا ہے۔ جو عورتوں کے بارے میں تصورات، مفروضات کو منفرد سیاق و سباق عطا کرتے ہیں۔ کہا جاتا ہے ثانیثی ادب کے متن میں کچھ امور اور معاملات ایسے ہوتے ہیں جن کو اسے صرف عورت ہی سمجھ سکتی ہے۔اور سمجھا سکتی ہے۔ کیونکہ عورت کے تجربات اور حساسیّت کو مرد کلی طور پر سمجھ نہیں پاتا۔ مارکسی فکریات میں ثانیثیت سے کچھ زیادہ دلچسپی اور ہمدردی کے جذبات نظر نہیں آتے کیونکہ یساریت پسند فکریات میں طبقاتی درجہ بندی میں خواتین کا علحیدہ وجود تسلیم نہیں کیا جاتا۔ اسی طرح فرائڈ کی فکر میں انسانی تعلقات کے عمل کیمیائی و انسلاکات اور بین العمل میں مرد کا آلہ تناسل کو ثانیثی تجزیات سے منسلک کردیتا ہے۔ جو شارح اور رہنما بھی ہے۔ جو قوت مقتدر بھی ہے۔ سوال یہ ہے کہ کیا ثانیثی تنقید اور مطالعوں کے زریعے عورت اپنے مادّی نظام کی گم شدہ شجرہ نسب کو دریافت کرسکتی ہے۔ حیدرقریشی نے  رقم طراز ہیں " صدیوں سے انسانی معاشرہ میں عورت کو کم تر درجہ دیا گیا...

The Impact of Melaka as a UNESCO World Heritage Tourist Area on the Motivations

Malays will not disappear from the world." The oath of Admiral Hang Tuah in the 15th century seemed to have received his "luck". When UNESCO designated Bandaraya Melaka as a World Heritage City on July 7, 2008, The aim of this research is to determine what factors influence the motivation of tourists visiting the Old City area of Bandaraya Melaka. The research methodology uses quantitative descriptive analysis with a sample size of 37 people. Variable (X1): psychological motivation has no effect on tourist motivation (Y), cultural motivation variable (X2) has no effect on tourist motivation (Y), social motivation variable (X3) has an effect on tourist motivation (Y), and fantasy motivation variable (X4) has an effect on tourist motivation (Y). The R2 value is 0.682, meaning that the influence of the independent variable on the dependent variable is 68.2%. While the remaining 31.8%, other variables amounting to 31.8 percent could be from medical treatment, costs, and travel services, which were not examined in this research.

Prevalence of and Factors Associated With Vitamin D Deficiency Among Afghan Adolescents Diagnosed at a Tertiary Healthcare Facility in Kabul, Afghanistan

Background: Vitamin D, also known as the sunshine vitamin, is formed in the skin from exposure to sunlight, and is absorbed from foods as well. It is important for calcium absorption and bone growth. Vitamin D status is linked to the pathogenesis of skeletal and non-skeletal disorders. Vitamin D deficiency is relatively prevalent all over the world. In studies conducted in other countries, adolescents are thought to have increased risk of vitamin D deficiency. Still, data is lacking about the prevalence of vitamin D deficiency among healthy Afghan adolescents. Objective: The aim of this study was to determine the prevalence of and to identify factors associated with vitamin D deficiency and severe vitamin D deficiency among Afghan adolescents (10-18 years of age) diagnosed at French Medical Institute for Mothers and Children (FMIC), Kabul. Material and Methods: An analytical cross-sectional study design was conducted from Jun to Sep 2016. Blood samples were obtained, serum 25OHD levels were measured, and the patients were divided into five diagnostic categories according to their serum 25OHD concentrations. 1) Sufficiency ≥30-100 ng/ml; 2) Insufficiency ≥20-30 ng/ml; 3) Deficiency <20 ng>/ml; 4) Severe deficiency <10 ng>/ml; 5) Intoxication >150 ng/ml. Collection of samples were made at Clinical Laboratory of FMIC and serum 25OHD analyses were carried out in the Biochemistry section. Results: A total of 308 adolescents were part of the sample for the final analysis. Of all, 202 (65.6%) were females and 106 (34.5%) were males. Out of total, 238 (77.3%) had either insufficiency, deficiency or severe deficiency of vitamin D. Among those, a large number of the participantss i.e., 107 (34.7%) had severe vitamin D deficiency, 81 (26.3%) had vitamin D deficiency, 50 (16.2%) had vitamin D insufficiency, and only 70 (22.7%) had vitamin D sufficiency. There were two cases of vitamin D intoxication, who were excluded from the study. Gender, sun-exposure, usage of sun protector, calcium+vitamin D supplement intake, Vitamin D rich foods intake, regular milk intake, the type of living in yards or apartments, skin colour of participants, and BMI were found as significant factors associated with vitamin D level Conclusion: There was a high prevalence of vitamin D deficiency among adolescents who visited a tertiary healthcare facility in Kabul. Low serum vitamin D concentration is prevalent among general Afghan population. Screening and ongoing investigation for vitamin D deficiency should be considered for all adolescents in the country. Based on our results, the