Search or add a thesis

Advanced Search (Beta)
Home > Control and Analysis of Switching Power Electronic Converter.

Control and Analysis of Switching Power Electronic Converter.

Thesis Info

Access Option

External Link

Author

Naveed Ashraf

Program

PhD

Institute

University of Engineering and Technology

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2020

Thesis Completion Status

Completed

Subject

Electrical Engineering

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/14659/1/Naveed%20Ashraf%20Electrical%202020%20uet%20lhr%20prr.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727720419

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


The suggested research is focused on the analysis, design, and development of the single-phase direct AC-to-AC converters. They are classified as voltage and frequency controllers. The AC voltage controllers are employed to solve the power system disturbances. The problem of voltage sag and swell is very common in the power distribution system that degrades the performance of the connected load and may cause their failure. In these circumstances, the power conditioning units such as dynamic voltage restorers (DVRs) are employed for their proper and safe operation that are realized with AC-to-AC converters. The voltage sags and swells issues are tackled by increasing and decreasing the line voltage respectively. The in-phase and out-of-phase output voltages are generated if AC voltage controllers can be operated with bipolar voltage gain. These characteristics can be realized if they operate in non-inverting and inverting modes. The voltage controllers having these features may also be employed as direct frequency changers (DFC) for variable speed drives and induction heating systems. The circuit and control complexity in these converters depend upon the number of controlled switching devices. The power conversion efficiency in these converters is directly related to unwanted switching and conduction losses caused by the switching devices. These losses depend on the number of switching devices, switching voltages, switching frequency, and switching currents. The high switching voltages and currents are the main problems in these converters. They not only increase the unwanted conversion losses but also increase the voltage and current rating of the switching devices. These problems become very serious in frequency boost operation. In variable frequency operation, the output is not in pure sinusoidal form, and it contains unwanted harmonics as it is obtained by inverting and non-inverting the input voltage. So here, we propose a novel AC-to-AC converter that has voltage and frequency regulation characteristics. It is capable of operating in the buck and boost fashion with non-inverting and inverting characteristics. Its operation is realized with a low count of the switching devices having low switching voltages and currents. These characteristics reduce the conversion losses and hence improve efficiency. The detailed analysis related to switching voltages and currents and conversion losses is also presented. The regulation of the output voltage is achieved through the pulse width modulation (PWM) control of one switch directly and other as indirectly. The direct PWM controlled (DPWM) switch is controlled with a high-frequency gating sequence. Its switching controls the operating states of the other switch called indirect PWM (IDPWM) controlled switch. The power quality problem in variable output frequency mode is determined by computing their harmonics coefficients analytically through the pulse selective approach. The problem of high voltage and current overshoots in boost frequency mode is tackled by developing a new DFC with low count of switching devices. Its output is realized through simple switching control scheme that is generated with any PWM generator as there is no need to synchronize the gating signals with input voltage. The worth of the proposed work is proved by comparing its performance parameters with the existing topologies. The simulation and practical results validate the effectiveness of the proposed research.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

ہیں تمھارے یہ سارے خواب ،جناب

ہیں تمھارے یہ سارے خواب، جناب
زلف و لب، دل، جگر، شراب، جناب

ایک ہی جان پر ستم لاکھوں
پلکیں نازک، گراں حباب، جناب

قیس کے پائوں میں ہیں زنجیریں
اور لب پر ہے بس جناب، جناب

ہو گا محشر میں اک نیا محشر
تم سے مانگیں گے جب جواب، جناب

دیکھ لو اب فضا کی آنکھوں میں
چاند، قوسِ قزح، گلاب، جناب

English in the Workplace: Business English as a Lingua Franca in Boardwalk Direct Selling Company

With the current international competition among global companies, Business English as a Lingua Franca (BEFL) has become a necessity. As for one, Boardwalk Direct Selling Company recognizes the adoption of the BEFL concept within the organization to equip its workforce with adequate English language skills at par with global standards. This study aims to assess the organization’s current English proficiency and the readiness of its employees to embrace BEFL. This also presents the major English language skills areas that need improvement through training intervention. A stratified sampling method is utilized to extract data via an online survey. Respondents are strategically chosen to represent different strata such as organizational departments or groups, job levels, tenure, and age. A convenient size of 34 respondents participated in this study. Generally, respondents acknowledge the importance of the English language skill set in their job functions and as criteria for their career growth. Half of the sampling population affirms their English language proficiency. However, the study reveals that Boardwalk employees are willing to subject themselves to improving their English skills, most particularly in speaking and writing aspects. Given their willingness, the employees recommend that the company strengthen its BEFL trainings across the organization. Moreover, with the current setup of mostly working from home due to COVID restrictions, majority of the employees prefer online learning.

An Empirical Analysis of Determinants of Tax Evasion: Evidence from Asia and Latin America

This study examines tax evasion problem which erodes revenue generation for the Tax authorities and Governments in the context of Asia and Latin America. The objective of this research is to explore major determinants which influence tax evasion through cross regional comparison of Asian and Latin American regions. This research provides a framework to understand the impact of socio-economic, behavioral, institutional and political factors towards the decision of evading taxes. The study has conducted an empirical investigation of twelve Asian and eight Latin American countries further divided into regions as South Asia, East Asia and South-East Asia and Central America and South America respectively, through OLS panel regression analysis and Fixed Effect (FE) approach using dataset from 1988 to 2017 derived from WEF Annual Reports. The measures that may help tax authorities to discourage tax evasion have also been highlighted in the last part of this thesis. The study concludes that the variables of Age, corruption, low Income level, Ease of doing Business, are positively associated for all the regions with varying magnitude with the dependent variable whereas, Gender, Services income, self-employment, High income level, Marginal Tax Rate, HDI, Public Trust in Politician and Rule of law are negatively associated for different regions impact factor variations are there. However, self-assessment, agriculture income, technological readiness and accountability show mixed results both insignificant and significant for different regions. It is concluded in this study that economic and institutional factor are more strong determinants of tax evasion in comparison with the demographic factors.