Thesis & Report (Master of Science in Electrical and Electronic Engineering)

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    A comparative study of AI-based and signal processing techniques for condition monitoring of power transmission networks
    (BRAC University, 2025-09) Khalif, Abdirizak Abdullahi; Huda, A. S. Nazmul
    Transmission lines are essential for transporting power over long distances as far as it is not always effective and it may also fail thus putting the flow of power at risk and the people who depend on power at risk as well. This is why the maintenance of their reliability and efficiency is of paramount importance in energy infrastructure of the contemporary world. This research aims at exploring the detection and classification of faults in power networks. Here, a novel hybrid model, DWT- CNN-BiLSTM, is presented which combines signal processing and deep learning and compares it with the classic machine-learning and deep learning approach. A dataset of 11,000 current and line-voltage samples that were provided in MATLAB SimPowerSystem evaluated the proposed model. Wavelet transform breaks down the signals by time-frequency, which represents transient faults as well as attenuating noise. The resulting coefficients are then inputted into a CNN, which produces spatial features, which are then inputted into a BiLSTM that yields bidirectional time information. One last Softmax layer allows fault detection and classification of multiple classes reliably. It is a robust, high-accuracy end-to-end pipeline that can be deployed in real time, and the accuracy of fault-detection is 99.86 %, and the accuracy of classification is 93.75%. Further proof of the effectiveness of the hybrid model is that the hybrid model surpasses single-method machine-learning and Deep learning baselines in terms of precision, accuracy and recall. Such findings show that the model can be applied in practice in real-time as a way of enhancing system stability in power-generation, predictive maintenance, or operational resiliency.
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    Comprehensive analysis of sweep assisted enhanced adaptive fuzzy – P&O algorithm for efficient MPPT PV system
    (BRAC University, 2025-09) Rahman, Muhammad Istianatur; Huda, A. S. Nazmul
    This research work proposes an algorithm that contains a dual-mode controller which uses adaptive fuzzy-enhanced P&O for fine-tuning steady-state control and sweep-based exploration for precise initialization for PV system with better oscillation, improved convergence speed and good tracking efficiency. This algorithm operates in two modes. The first mode is the sweep mode which is used to bring the operating point into the area of the Maximum Power Point (MPP). In this mode the duty cycle (D) is perturbed with a fixed step size, which sweeps the operating point across the entire I-V curve. Simultaneously, an initial estimate of the MPP voltage (Vmpp,est) is calculated using an empirical formula that incorporates real-time measurements of average irradiance (Gavg) and temperature (T). A sweep counter is increased if the operating point is far from the estimated MPP. After a predefined number the algorithm transitions to the second mode. In this mode the system first calculates the changes in power and voltage using this value the FIS computes the adaptive step size and using that the duty cycle is generated for the PV system. A 100kW PV system is modeled in MATLAB/SIMULINK, using the proposed technique the convergence time is obtained 16.8ms the voltage oscillation is 0.7V and the tracking efficiency is 99.6%.
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    Development of custom RISC-V central processing unit (CPU) with open-source Google + SkyWater 130 nm
    (BRAC University, 2025-09) Rahman, Md. Shyeem; Rahman, Touhidur; Hossain, MG Sorwar; Harun-Ur-Rashid, A. B. M.; Rahman, Md. Mosaddequr
    The chip design industry relies heavily on secretive methodologies and designs. A significant gap exists between commercial design environment and open-source environment. Although a range of open-source CAD tools has been developed to address aspects such as system design, logic synthesis, place-and-route, test insertion, and verification, there is no established toolchain for open-source library characterization. This thesis aims to develop that toolchain for open-source library characterization and develop a custom standard cell library based on Google + SkyWater 130nm technology. To further verify the toolchain and libraries, a RISC- V CPU is designed with the same library using established open-source Place and Route tools and simulated for result verification. Therefore, this work aims to tackle issues related to open-source chip design while diving deep into open-source tools to design a RISC V CPU. To achieve this, the gaps which remain between the ASIC design done with commercial design tools and open-source tools are addressed and bridged.
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    Evaluating the impact of component unavailability on power distribution feeder reliability
    (BRAC University, 2025-05) Roy, Bannay; Huda, A. S. Nazmul
    The power distribution system reliability is the key driver for service quality as well as customer satisfaction. In this study, the impact of component unavailability on overhead as well as underground distribution feeder reliability is analyzed in terms of reliability metrics like SAIFI, ASAI, ENS, CAIDI, and SAIDI. Due to environmental conditions, overhead power distribution lines face many challenges, while underground power distribution cables are superior to this due to their resiliency and performance. The reliability of distribution feeders varies based on the analysis of different protective devices such as fuses, disconnecting switches, and alternative supplies as well as the restoration process of transformer failure. Using the analytical approach, this study evaluates the reliability of both feeder types such as overhead and underground in different unavailability cases. It is observed that the reliability level of feeders is greatly impacted by the absence of these devices. The results also show that the feeder reliability is improved when overhead power lines are replaced by underground power cables, resulting in a reduced number of outages and durations.
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    Study the dynamic performance of an AC multimachine power system with PV integration
    (BRAC University, 2025-05) Rahman, Mahfuzur; Rahim, Abu Hamed M. Abdur
    The integration of photovoltaic (PV) systems into multimachine AC power grids is vital for addressing the growing demand for clean and sustainable energy. This study investigates the dynamic performance of a multimachine AC power system with integrated PV generation. A detailed AC system model is developed. After conducting load flow analysis, one of the synchronous generators is replaced with a PV system to simulate renewable energy penetration. PV model is implemented to accurately represents its behavior in the grid. A PI controller is designed and applied to the system to enhance grid stability through voltage and frequency regulation. Since PV systems typically inject only real power and do not contribute reactive power support, thereby directly enhancing the damping characteristics of the system. The model development and simulations are performed and validated in MATLAB. Results reveal the impact of PV integration on the multimachine system, showing variations in transient stability and fault response. The integration of PV into the AC system contributes energy production as well as improves system transient performance, reducing generator stress, and improving overall dynamic stability. This study offers 5th order modeling for generators and new insights into the role of renewable generation in supporting conventional grid systems, particularly under transient and dynamic operating conditions.
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    Design of a Phase-Locked Loop (PLL) using GPDK045 CMOS Technology
    (BRAC University, 2025-02) Mohonto, Nerob Kumar; Rahman, Touhidur
    A Phase-Locked Loop (PLL) is a feedback control system used to synchronize the frequency and phase of an output signal with a reference signal widely applied in communication systems, data recovery and frequency synthesis. The high-frequency operation and rapid switching of PLL circuits often result in substantial power consumption, posing challenges in designing for high-speed applications. This project addresses these challenges by developing a PLL that balances performance with power efficiency. The PLL architecture includes a Phase Frequency Detector (PFD) to compare the phase difference between input and feedback signals, a Charge Pump (CP) and Loop Filter (LF) to process this phase error into a stable control voltage and a Voltage-Controlled Oscillator (VCO) that adjusts output frequency accordingly. Performance metrics, including lock time, lock range, phase margin, gain margin, jitter, and output frequency range are analyzed and optimized for stability and efficiency. Using Cadence Virtuoso simulations, the project evaluates key trade-offs, producing a PLL design that maintains precise frequency control and low power consumption, ideal for high-performance electronic applications.
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    Feasibility study of renewable energy integration in an islanded microgrid: a Bangladesh's perspective
    (BRAC University, 2024-12) Alam, Zubayer; Rahman, Md. Mosaddequr
    This study proposes a design of a microgrid took into account the Bangladeshi island of Dublar Char. A scenario-based analysis which comprises one system of standalone PV and wind systems along with battery storage and another system considering backup generator have been considered based on the calculated load requirement of the Dublar Char. The average load demand of the Dublar Char, Island area is 5,246.9 kWh/day. Life Cycle Cost analysis claims, 20% load dependency for PV and battery storage and 80% load dependency for wind became the optimum design solution for the Dublar Char community. The total land required for PV module, Wind Turbine and Battery storage system, would be approximately 2 acres. Based on a 20-year project life, the return on investment is expected to be 9.09 years If the diesel generator is capable of providing a backup energy supply to the PV night load demand, the LCC will be significantly lower than regular and less space will need to be occupied (1.5 acres of land). Based on a 20-year project life, the return on investment is expected to be 6.27 years.
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    Broadband, polarization insensitive and tunable THz metamaterial absorber using graphene and phase change material
    (BRAC University, 2024-12) Preety, Nazia Homaira; Mohsin, Abu S. M.
    Metamaterials are artificially-engineered materials with features that are not easily evident in naturally occurring materials. They can be used for perfect lenses, invisibility cloaking, perfect absorption and transmission and other applications because they exhibit novel properties such as left-handed behaviour, a negative refractive index, a classical analog of electromagnetically-induced transparency, extraordinary transmission, negative Doppler effect and more. Metamaterial-based perfect absorbers are potential candidates for practical use as perfect absorbers. In this study, we looked at a novel strategy to build a graphene metamaterial (GMM) based terahertz (THz) absorber with dual-mode functionality, tunability and broadband absorption. We carried thorough simulations on four alternative configurations and observed the maximum absorption and its efficiency. The absorber is designed to work in two unique modes, increasing its suitability for various THz applications, by manipulating resonant structures and the materials. We also did detailed simulation on five distinct configurations of tuned resonant structures, which differed from those in the previous structures, and concluded that the optimized structure with phase change material (PCM) can accomplish bandwidth almost twice as large. Phase change materials are promising possibilities for electronic Flash memory. They are often utilized in commercial optical disks and rewritable media. Phase change material (PCM) is extraordinary compounds with unique switchable properties leading to an explosion of new applications in the field of electronics and photonics. Furthermore, the absorber is polarization insensitive, has a wide viewing angle and responds quickly. Metamaterial structures are mainly three layered. Two optimized structures of metamaterial absorbers have been proposed. This study gives insight into the new method that increases the high absorption width, as well as the great potential in the multifunctional modulator, considering with and without the phase transition material. Our primary goal is to design a graphene-based metamaterial absorber that can achieve near unity frequency absorption that has maximum bandwidth. We have designed simple structure compared to the existing hybrid absorbers that can give nearly frequency bandwidth 7.69THz dualband and multiband absorption. Furthermore, we demonstrated step-by-step reliable methodologies to the fabrication of graphene-based metamaterial.
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    The impact of natural dust on outdoor PV panels: the performance analysis and short-term prediction
    (BRAC University, 2024-09) Islam, S. M. Shamsraj; Rahman, Md. Mosaddequr
    This study focuses on the performance of PV modules, assessing the impact of dust in a suburban area of Bangladesh. Data was collected between December 2022 and February 2023 from two photovoltaic (PV) panels, one is kept clean and other one intentionally left dusty. The analysis is divided into two sections: performance analysis and prediction analysis of PV panels. The findings reveal that, dust significantly reduce energy output, with a reduction of 5.09%, 4.75% and 3.95% in December, January and February, respectively. Additionally, weather condition (sunny and rainy) influences the short circuit current of the PV modules. The long-term effect of dust accumulation on panel performance are also evident. Furthermore, in time series analysis, the LSTM model was trained using two months of data, and its prediction for short circuit current closely aligned with the experimental data, achieving low RMSE value of 6.28 and 11.46, respectively.
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    A Statcom based PMSG wind energy system
    (Brac University, 2022-09) Thapa, Anil; Rahim, Abu Hamed M. Abdur
    With ever increasing growth of the wind power, the large penetration of wind energy has brought opportunities along with challenges integrating it in the existing power system grid. A power system network is complex and the contingencies are inevitable. The energy generated from the wind is intermittent and need proper Maximum Power Point Tracking (MPPT) Algorithm with appropriate power electronics device. The situation is more difficult for variable speed PMSG system connected to weak grid. The grid codes are necessary to strictly comply with a set of rules that address reactive power control, power quality, voltage ride through to minimize the grid instability and power quality issues. STATCOM is one of the promising FACTS devices extensively used in solving power quality issues. This project studies the role of permanent magnet synchronous generator (PMSG) wind turbine system with STATCOM controller for reactive power compensation. A detailed model of the PMSG along with the dynamics of the converters have been included. DC link capacitor voltage of the back-to-back converter needs to be maintained within strict limits for smooth power transfer in the system. The STATCOM is placed at the terminal of the grid side converter. An independent P-Q controller is designed for STATCOM to provide the necessary reactive power to regulate DC link capacitor voltage and maintain stability. The simulation studies have shown that the proposed controller provides good damping and settles the transients satisfactorily following the disturbances.