AIUB Journal of Science and Engineering (AJSE)

FRT and Transient Stability Augmentation of Grid-Connected PV Station Using Virtual Synchronous Generator

2021-12-31T03:24:37+00:00

Due to the extensive integration of renewable energy sources (RESs), i.e., photovoltaic (PV) system, the future power system is developing into an inverter-based system from a dominated alternator-based power system. This massive penetration of inverter-based PV system reduced the system inertia and damping characteristics of the power grid, impacting the fault ride-through (FRT) capability and causes frequency instability. Modern grid codes require that PV systems should work in the same way as conventional power plants and assist the system during transient state. However, most of the conventional inverter control mechanisms failed to fulfill the requirements of grid codes, especially when the penetration ratio of the PV system is close to the conventional unit. Therefore, this paper proposes a virtual synchronous generator (VSG) control mechanism of PV system inverter to augment FRT competency and frequency stability. The proposed VSG control system mimics the behavior of conventional power plants. To observe and evaluate the proposed controller behavior, simulation analyses were executed in the PSCAD/EMTDC software for both proposed and conventional controllers. The simulation results clearly indicate that the proposed VSG control system has sufficient damping characteristics to ensure FRT capability and frequency stability.

Energy Harvesting Technology by Converting Waste Heat Energy from Automobiles

2021-12-31T03:24:15+00:00

In this project, heat energy is used for generating
electrical energy by a conversion process. The energy harvesting
from the heat of motorbike has become a new source of portable
energy for rechargeable gadgets. In contrary, the conventional
nonrenewable energy sources have likewise added to an
expansion in contamination on the planet and a disintegration of
human wellbeing. From the electrical energy, the mobile phone
will be charged. A thermoelectric generator has been connected
to the hot portion of the motorbike and while riding the bike, any
kind of chargeable device will get charged. The prototype of this
research work has effectively harvested electrical energy from
heat using thermoelectric generator and has managed to provide
enough power at different speeds of the motorbike.

Online Education in HEIs in Bangladesh moderated by COVID-19: Modified UTAUT2

2021-12-31T03:23:51+00:00

The whole world, including Bangladesh is brought to a standstill by the pandemic of COVID-19. All the hustling-bustling of a densely populated country has come to a quiescent halt; the only sound remaining is the whisper of anxiety. The HEIs in Bangladesh is also struggled to react to this sudden catastrophe; magnified by uncertainties. Compared to public universities, the private universities of the country managed to react the fastest and are making sweeping changes in a very short period of time, shifting traditional face-to-face course content/teaching to online content/teaching. The shift to fully functional online teaching learning platform was sudden and with minimum preparation. To investigate the perception of the private universities community in Bangladesh with this new teaching learning method, this paper adopted the Unified Theory of Acceptance and Use of Technology (UTAUT) model, focuses on stakeholders’ behavioral intention, availability of the online platform, prior experience, attitude towards usage (ease of use and usefulness) and most importantly the impact of COVID-19 pandemic. Additionally, the paper also discusses the issues of social and cultural impact. It was found that all the UTAUT attributes are positively correlated with the Behavioral Intention and eventually to Use Behavior of students in adopting online education. Moreover, unexpected, and unprecedented impact of COVID-19 pandemic also effected their behavioral intention towards accepting online education.

Study and Analysis of Photonic Crystal Fiber for Broadband Laser Source Design

2021-12-31T03:23:28+00:00

Photonic Crystal Fiber (PCF) has been a topic of extensive research in the field of nonlinear fiber optics. It is due to its combination of linear and nonlinear properties which ultimately results in the phenomenon having various types of applications. One of the phenomena is supercontinuum generation that has been extensively studied numerically and experimentally over the last few decades as it has important applications in the field of medical imaging and sensing. In this paper, we numerically analysed and studied PCF of hexagonal core with various parameters and propose our novel ‘Star in Hexagon’ design as a good candidate for the broadband supercontinuum generation and hence a broadband laser source. We numerically pumped a long 10 mm PCF of this kind at 3.1 um wavelength with a pulse having a power of 4000 W and a temporal width of 50 fs. A broadband supercontinuum ranging from 1.7 um to 18 um was obtained. The generated spectrum is quite well in the mid-infrared region. Hence it can be utilised for Mid – Infrared (MIR) applications.

A PLS-SEM Approach to Connect Fertility, GDP, and Childhood Mortality with Female life Expectancy (FLE) in Bangladesh

2021-12-31T07:46:36+00:00

A reasonable number of studies on the effect of Female life expectancy (FLE) upon the quality of women's lives in developed countries have been done. Bangladesh lacks such a study. We explore the effect of decreasing fertility and childhood mortality rates on FLE in Bangladesh and evaluate the potential impthe act of the demographic transition on GDP. Also, we investigate the trends and patterns of different factors from 1995 to 2018. Partial Least Squares-Structural Equation Modeling (PLS-SEM) is functioned to fit an appropriate model to link fertility, GDP, and childhood mortality with FLE. The significance of the relationships has also been assessed. Results indicate that declines in fertility and childhood mortality have made significant improvements in FLE. The prospects of demographic transition due to fertility decline have been analyzed, and challenges to achieve it are highlighted.

Review of Different Error Metrics: A Case of Solar Forecasting

2021-12-31T03:22:41+00:00

Renewable energy systems (RES) are no longer confined to being used as a stand-alone entity in the modern era. These RES, especially solar panels are also used with the grid power systems to supply electricity. However, precise forecasting of solar irradiance is necessary to ensure that the grid operates in a balanced and planned manner. Various solar forecasting models (SFM) are presented in the literature to produce an accurate solar forecast. Nevertheless, each model has gone through the step of evaluation of its accuracy using some error measures. Many error measures are discussed in the literature for deterministic as well as probabilistic solar forecasting. But, each study has its own selected error measure which sometimes landed on a wrong interpretation of results if not selected appropriately. As a result, this paper offers a critical assessment of several common error metrics with the goal of discussing alternative error metrics and establishing a viable set of error metrics for deterministic and probabilistic solar forecasting. Based on highly cited research from the last three years (2019-2021), error measures for both types of forecasting are presented with their basic functionalities, advantages & limitations which equipped the reader to pick the required compatible metrics

Integrated Mobile Learning Education Supply Chain Management for Higher Learning Institution

2021-12-31T03:22:18+00:00

The mobile devices are used to execute the teaching-learning-evaluation process in Mobile Learning (m-learning) methodology. M-learning is a trending field in educational organizations, companies, and for individual study. With the explosion of mobile device ownership among the users aged within 18–29 years who are also the attendees of the higher learning institution (HLI), gives us the opportunity to consider the use of m-learning methodology to be embedded in the HLI beside traditional methodologies. Exceptional circumstances such as the COVID-19 pandemic when traditional face-to-face methodology suddenly changed to online paradigm, is also forcing us to strongly consider the m-learning approach. However, HLI may not have a general policy to implement m-learning into the traditional learning environment. A proper educational outcome needs to be configured to implement a new process into the traditional process. Therefore, a model integrating the m-learning aspects and the education supply chain management factors obtained from this study may benefit the stakeholders of HLI, especially educators and students.