Power and Energy Commons^™

Characterization, Analysis, And Application Of Wbg Power Devices For Future Power Conversion Systems, Ali Mahmoud Salman Al-Bayati

Electronic Theses and Dissertations

Semiconductor power devices are the most momentous constituents of any power converter system. Fast switching, compactness, high performance and efficiency, and high temperature operation are the exacting challenges experienced by conventional silicon (Si) power device based power converters in many applications. In this dissertation, the wide bandgap (WBG) power devices are studied and used to transcend the limitations imposed by the Si power devices. It mainly focuses on characterization and analysis of the behavior of WBG power devices as well as design and development of efficient, high performance, and reliable dc–dc power converters based on WBG technology. First, using computer …

Nanoscale Spatial Realization Of Grain Boundary Defects And Its Passivation In Perovskite Solar Cells, Ashraful Haider Chowdhury

Electronic Theses and Dissertations

Perovskite solar cells (PSCs) have seen significant improvement in photovoltaic performance in recent days. However, the performance of PSCs is limited by the defects present at grain boundaries (GB). The study adapted here discusses the nanoscale spatial realization of grain boundary defects and its passivation in perovskite solar cells. Conventional MAPbI3 and state- of-the-art Cs5(MA0.17FA0.83)95Pb(I0.83Br0.17)3-FAMACs perovskite GBs were studied in detail using atomic force microscopy. The density of trap states calculation by kelvin probe force microscopy (KPFM) shows that FAMACs perovskites have lower defects at GB compared with MAPbI3 perovskites. This improvement is caused by the less activation energy of …

Additive And Interface Engineering Of Lead-Tin Mixed Low-Bandgap Perovskite Solar Cells For Higher Efficiency And Improved Stability, Nabin Ghimire

Electronic Theses and Dissertations

Lead (Pb) -Tin (Sn) mixed perovskites suffer from large open-circuit voltage (VOC) loss due to the rapid crystallization of perovskite film, creating Sn and Pb vacancies. Such vacancies act as defect sites expediting charge carrier recombination, thus hampering the charge carrier dynamics and optoelectronic properties of perovskite films. In the first project, we focused on the passivation of perovskite surface defects to increase the opencircuit voltage of the 1.25 eV low-bandgap perovskite solar cells by utilizing a trace amount of Phenethylammonium iodide (PEAI) in the perovskite precursor solution as a doping agent. The incorporation of PEAI in perovskite precursors improved …

Development Of Efficient Wide-Bandgap Perovskite Solar Cells With Composition And Interface Engineering, Khan Mamun Reza

Electronic Theses and Dissertations

Metal halide perovskites are considered the most promising solar energy technology because of their distinct properties, such as defect tolerance, low cost, easy fabrication due to solution-processibility, band tunability, etc. Due to these properties, the efficiency of perovskite solar cells reaches more than 25% and approaches the limit of singlejunction within last few years. To increase the efficiency further in a more cost-effective way, double junction tandem solar cells with an efficient ‘top’ wide-bandgap cell is desired. But wide-bandgap perovskites still face some critical issues, such as poor morphology, smaller grain size, the formation of excessive lead halides, light-induced halide …

Model-Based Control Methods To Improve The Power Qualify Of Grid-Connected Single-Phase Inverters., Moath Alqatamin

Electronic Theses and Dissertations

Power electronic converters are commonly used for interfacing distributing generation sources (DGs) to the electrical power system networks. This is necessary because these DGs usually have different output characteristics and cannot be connected directly to the local load and/or the grid. The power electronic front-end converter is an inverter whose dc link is fed by an ac/dc converter or by a dc/dc converter, according to the DG source type. The commercial front-end inverters are designed to operate either in grid-connected (GC) mode or in stand-alone (SA) mode. In the SA mode, the inverter is connected to local load, but in …

Microgrid-Enabled Reactive Power Support To Enhance Grid Economics, Sarhan Hasan

Electronic Theses and Dissertations

Reactive power plays an essential role in voltage control and stability in electric power systems. Various Volt/VAR techniques are utilized in electric power systems to maintain the voltage profile within defined acceptable limits and accordingly provide reliability and stability. Reactive power has been commonly generated through large-scale synchronous generators or distributed capacitor banks to provide proper transmission and distribution level system management, however, reactive power can be further used as an effective means to reduce total system operation cost. In this dissertation, an optimal reactive power model is proposed to determine the optimal nodal reactive powers that result in the …

Deep Reinforcement Learning For The Optimization Of Building Energy Control And Management, Jun Hao

Electronic Theses and Dissertations

Most of the current game-theoretic demand-side management methods focus primarily on the scheduling of home appliances, and the related numerical experiments are analyzed under various scenarios to achieve the corresponding Nash-equilibrium (NE) and optimal results. However, not much work is conducted for academic or commercial buildings. The methods for optimizing academic-buildings are distinct from the optimal methods for home appliances. In my study, we address a novel methodology to control the operation of heating, ventilation, and air conditioning system (HVAC).

We assume that each building in our campus is equipped with smart meter and communication system which is envisioned in …

Experimental Investigation Of Low-Voltage Silicon Carbide (Sic) Semiconductor Devices For Power Conversion Applications, Saleh Salem H. Alharbi

Electronic Theses and Dissertations

Enhancing the performance and efficiency of power converter systems requires fast-switching power devices with considerably low switching and conduction losses. Silicon (Si) semiconductor devices are the essential components in electronic converter designs, and their behaviors and switching characteristics determine the system’s overall performance and efficiency. These conventional Si devices are nearing to hit their physical and operational limits in meeting power converter requirements with respect to high temperature and large voltage conditions. However, silicon carbide (SiC) power devices enable greater converter efficiency and better power density, particularly under hard switching frequencies and high output voltages due to their outstanding material …

Real-Time Detection Of Demand Manipulation Attacks On A Power Grid, Srinidhi Madabhushi

Electronic Theses and Dissertations

An increased usage in IoT devices across the globe has posed a threat to the power grid. When an attacker has access to multiple IoT devices within the same geographical location, they can possibly disrupt the power grid by regulating a botnet of high-wattage IoT devices. Based on the time and situation of the attack, an adversary needs access to a fixed number of IoT devices to synchronously switch on/off all of them, resulting in an imbalance between the supply and demand. When the frequency of the power generators drops below a threshold value, it can lead to the generators …

Power System Frequency Control And Stability Analysis With Increasing Renewable Energy Penetration Level, Weihang Yan

Electronic Theses and Dissertations

With the ever-increasing penetration level of renewable energy generation units and the replacement of traditional synchronous generators, the issues associated with the deteriorated performance of power system frequency regulation and potential grid frequency instability become more significant. In this dissertation, the inertial control algorithms are investigated and analyzed for power electronics converter in a renewable energy generation unit. The concept and design of Virtual Synchronous Generator are comprehensively discussed, such that the small-signal stability and frequency stability of power systems with high renewable energy penetration level can be enhanced. Moreover, both nonlinear dynamic model and small-signal linearization of Virtual Synchronous …

Aggregated Der Management In Advanced Distribution Grids, Mohsen Mahoor

Electronic Theses and Dissertations

Evolution of modern power systems are more distinct in distribution grids, where the growing integration of microgrids as well as distributed energy resources (DERs), including renewable energy resources, electric vehicles (EVs), and energy storage, poses new challenges and opportunities to grid management and operation. Rapid growth of distribution automation as well as equipment monitoring technologies in the distribution grids further offer new opportunities for distribution asset management. The idea of aggregated DERs is proposed as a remedy to streamline management and operation of advanced distribution grids, as discussed under three subjects in this dissertation. The first subject matter focuses on …

Experimental Evaluation Of Medium-Voltage Cascode Gallium Nitride (Gan) Devices For Bidirectional Dc–Dc Converters, Salah Salem H. Alharbi

Electronic Theses and Dissertations

As renewable energy sources, such as photovoltaic (PV) cells and wind turbines, are rapidly implemented in DC microgrids, energy storage systems play an increasingly significant role in ensuring uninterrupted power supply and in supporting the reliability and stability of microgrid operations. Power electronics, especially bidirectional DC–DC converters, are essential parts in distributed energy storage and alternative energy systems because of their grid synchronization, DC power management, and bidirectional power flow capabilities. While there is increasing demand for more efficient, compact, and reliable power converters in numerous applications, most existing power converters are hindered by traditional silicon (Si) based semiconductors, which …

Lithium-Ion Battery And Beyond: Oxygen Vacancy Creation In Tungsten Trioxide And Surface Modification Of Lithium Metal, Rajesh Pathak

Electronic Theses and Dissertations

The graphite-based anode material has a low theoretical specific capacity of 371 mAh g-1. The transitional metal oxides (TMOs) are considered a better choice owing to their relatively higher specific capacity. Among TMOs, tungsten trioxide (WO3) is considered promising due to a higher specific capacity of 693 mAh g-1, low cost, mechanically stable, and eco-friendly. It has been a challenge to utilize the TMOs as anode materials as they suffer from poor electronic conductivity and large electrode volume expansion during discharge/charge cycles. In our first project, we demonstrate a unique self-recovery of capacity in reduced WO3 by the incorporation of …

Optimization-Based Fast-Frequency Support In Low Inertia Power Systems, Ujjwol Tamrakar

Electronic Theses and Dissertations

The future electrical energy demand will largely be met by non-synchronous renewable energy sources (RESs) in the form of photovoltaics and wind energy. The lack of inertial response from these non-synchronous, inverter-based generation in microgrids makes the system vulnerable to large rate-of-change-of-frequency (ROCOF) and frequency excursions. This can trigger under frequency load shedding and cause cascaded outages which may ultimately lead to total blackouts. To limit the ROCOF and the frequency excursions, fast-frequency support can be provided through appropriate control of energy storage systems (ESSs). For proper deployment of such fast-frequency control strategies, accurate information regarding the inertial response of …

Tailoring The Grain Boundaries Of Wide-Bandgap Perovskite Solar Cells By Molecular Engineering, Khalid Emshadi

Electronic Theses and Dissertations

Due to the attraction of fabricating highly efficient tandem solar cells, wide-bandgap perovskite solar cells have attracted substantial interest in recent years. However, polycrystalline perovskite thin-films show the existence of trap states at grain boundaries, which diminish the optoelectronic properties of the perovskite and thus remains a challenge. This research demonstrates a one-step solution-processing of the [MA_0.9Cs_0.1Pb(I_0.6Br_0.4)3] wide-bandgap perovskite using Phenylhydrazine Iodide with amino groups to successfully passivate the trap density within grain boundaries and increase the perovskite grain size. The reinforced morphology and grain boundaries treatment considerably enhanced the photovoltaic performance …

Enhanced Charge Carrier Dynamics And Defects Passivation In Hybrid Perovskite Solar Cell Using A Novel Organic Halide Salt, Md Ashuqur Rahman Laskar

Electronic Theses and Dissertations

In the last few years, active research works on hybrid perovskite solar cells (HPSCs) have been going on throughout the world as a part of clean energy revolution. HPSCs have already proved their potentiality as future solar technology through their promising photovoltaic performances and ability for low temperature based solution processing. Nevertheless, still there are remaining challenges of better charge carrier dynamics and defects minimization in HPSCs. Overcoming these challenges are very important to achieve high power conversion efficiency (PCE) practically. Aiming this, a novel organic halide salt called Phenylhydrazinium Iodide (PHAI) is introduced as additive with CH₃NH …

Surface And Structure Engineering For Next Generation Lithium Metal Batteries, Ke Chen

Electronic Theses and Dissertations

Lithium (Li) metal has been considered as one of the most promising anode materials to replace conventional graphite for Li-ion battery due to its high theoretical capacity (3860 mAh g-1) and low electrochemical potential (-3.04 V vs standard hydrogen electrode). However, it still faces some problems such as unstable solid electrolyte interphase (SEI), uncontrolled Li dendrites growth, and infinite volume change during battery charging/discharging. To develop a stable and low-cost Li metal anode for next-generation Li metal battery, in this dissertation, we have made efforts to understand and solve these problems in two aspects, by introducing an artificial SEI and …

Computational Intelligence Approaches For Energy Optimization In Microgrids, Tamal Roy

Electronic Theses and Dissertations

The future electrical system termed as smart grid represents a significant paradigm shift for power industry. Nowadays, microgrids are becoming smarter with the integration of renewable energy resources (RESs) , diesel generators , energy storage systems (ESS), and plug-in electric vehicles (PEV or EV) . However, these integration bring with new challenges for intelligent management systems. The classical power generation approaches can no longer be applied to a microgrid with unpredictable renewable energy resources. To relive these problem, a proper power system optimization and a suitable coordination strategy are needed to balance the supply and demand. This thesis presents three …

Distributed Machine Learning Approach To Fast Frequency Response-Based Inertia Estimation In Low Inertia Grids, Abodh Poudyal

Electronic Theses and Dissertations

Recent updates to the IEEE 1547-2018 standard allow active participation of distributed energy resources (DERs) in power grid services with the goal of increased grid reliability and resiliency. With the rapid growth of DERs towards a low inertia converter-dominated grid, the DERs can provide fast frequency response (FFR) services that can quickly counteract the change in system frequency through inertial support. However, in low voltage grids, frequency and voltage face dynamics coupling due to a high resistance to reactance ratio and cannot be controlled separately as in the bulk electric grid. Due to the coupling effect, the control of one …

Impact Of Grid-Following And Grid-Forming Ders On Resilient Operation Of Holonic Grid, Ali M. Alsenan

Electronic Theses and Dissertations

This thesis investigates how different distributed energy resources (DERs) impact the resilience operation of a holonic grid. The holonic grid consists of two or more connected microgrids and /or provisional microgrids (PMGs). The type of the DER, i.e., grid-forming or grid-following, affects the operations of the holonic grid, particularly during the islanded mode. To study this emerging and timely topic, a resilience-oriented holonic grid optimal operation model is proposed. This model carefully formulates the operations of both grid-forming and grid-following DERs. A variable value of lost load (VoLL) is further employed in the proposed model to help quantify and monetize …

Triple-Junction Solar Cells : In Parallel., Levi C Mays

Electronic Theses and Dissertations

This paper looks into the current inefficiency of solar cells and attempts a few alternative solar cell structures in order to provide a more effective source of renewable energy. Currently, multi-junction solar cells are being developed to capture the sun’s light more efficiently. One of the ideas in this paper is to add a window to see if the addition of such a layer into a junction will increase the voltage while maintaining nearly the same current output. Central to this paper is the rearranging of the conducting layers of the multi-junction cell so that the junctions can be connected …

Control Strategy For A Small-Scale Microgrid Based On Battery Energy Storage System-Virtual Synchronous Generator (Bess-Vsg), Wei Gao

Electronic Theses and Dissertations

As one of widely deployed renewable energy resources, PV power is playing a very important role in microgrids today. It has advantages such as making the best of natural solar energy and being friendly to our environment. In this thesis, solar PV based microgrid is studied using modeling and simulation. Microgrid can run in either grid-connected-mode or islanded-mode. However, there are also some disadvantages for solar power. For solar panel, its output is influenced by weather conditions such as illumination intensity and temperature. In addition, during the control process of grid-connected mode, it is hard to guarantee its output power …

Solar Forecasting And Integration In Power Systems, Mohana Alanazi

Electronic Theses and Dissertations

Renewable energy resources are becoming critical players in the electricity generation sector, primarily due to viability in combating global warming, effectiveness in reducing pollution caused by fossil fuel based generation, and diversifying energy mix to ensure energy security and sustainability. Solar energy is one of the most common types of renewable energy that has grown rapidly over the past decade and is anticipated to grow even faster in the future. Power supply from renewable resources is forecasted to surpass other types of generation in a foreseeable future. Numerous factors, including but not limited to the dropping cost of solar technology, …

A Study On Distributed Generation With A Focus On Solar Power, Shravan Kumar Tomar

Electronic Theses and Dissertations

Centralized generation is when electric power is produced in a large scale of tens of MWs and is located away from the end user. This kind of production is connected to a series of high-voltage transmission lines. Electricity is then delivered to the end user through a network of distribution grids. Centralized generation tend to have multiple end user with multiple user profiles.

Distributed Generation is when is produced in a small scale and is located at the site of or very close to the end user. There are many ways distributed generation can be achieved, Solar power being the …

Design And Analysis Of A Non-Isolated High Gain Step-Up Cuk Converter, Yasser Almalaq

Electronic Theses and Dissertations

Renewable energy sources, such as solar energy, are desired for both economic and ecological issues. These renewable energy sources are plentiful in nature and have a terrific capability for power generation. The only drawback of solar energy, which is one of the best forms of energy sources, is that the output has a low voltage and needs to be stepped up in order to be inserted into the DC grid or an inverter for AC applications. To overcome this drawback, a high gain DC-DC power converter is required in this kind of system. These power converters are needed for a …

Paving The Way For Multidisciplinary Smart Campus Infrastructure: Leveraging Du's Unique Campus For The Advancement Of Smart Campus Culture, Camerron T. Mismash

Electronic Theses and Dissertations

Institutions are embracing smart technologies to reap their benefits while simultaneously innovating new uses. From localized renewable energy generation to health monitoring and everything in between, academic campuses globally are paving the way for smart technology application. Eight primary categories have been identified in which institutions are applying smart technologies. Energy development is on the forefront of these smart initiatives. The University of Denver has begun its Smart Campus Initiative by implementing a revolving fund to invest in campus improvements related to the offset of carbon. By comparing how institutions are investing in smart campus initiatives and analyzing costs associated …

Machine Learning For Load Profile Data Analytics And Short-Term Load Forecasting, Md. Rashedul Haq

Electronic Theses and Dissertations

Short-term load forecasting (STLF) is a key issue for the operation and dispatch of day ahead energy market. It is a prerequisite for the economic operation of power systems and the basis of dispatching and making startup-shutdown plans, which plays a key role in the automatic control of power systems. Accurate power load forecasting not only help users choose a more appropriate electricity consumption scheme and reduces a lot of electric cost expenditure but also is conducive to optimizing the resources of power systems. This advantage helps while improving equipment utilization for reducing the production cost and improving the economic …

Energy Optimization And Coordination Frameworks For Smart Homes Considering Incentives From Discomfort And Market Analysis, Priti Paudyal

Electronic Theses and Dissertations

The electricity demand is increasing with the growing use of electricity-based appliances in today’s world. The residential sector’s electricity consumption share is also increasing. Demand response (DR) is a typical way to schedule consumers’ energy consumption and help utility to reduce the peak load demand. Residential demand management can contribute to reduce peak electric demand, decrease electricity costs, and maintain grid reliability. Though the demand management has benefits to the utility and the consumers, controlling the consumers electricity consumption provides inconvenience to the consumers. The challenge here is to properly address the customers’ inconvenience to encourage them to participate and …

Techno-Economic And Sustainability Study Of Pv Inverter Controllers In Distribution Networks For Voltage Regulation, Kapil Duwadi

Electronic Theses and Dissertations

Increasing distributed solar installations in low voltage distribution grids tend to increase the feeder voltage. The rise in voltage is only acceptable to a certain limit, and control strategies are required to keep voltage within defined bounds for equipment safety and system reliability. PV inverter control strategies are cost-effective methods to prevent overvoltage. Different inverter control strategies have different impacts on their techno-economic performance, ultimately affecting their sustainability. An evaluation framework for long-term techno-economic and sustainability analysis of overvoltage prevention methods in PV-rich LV networks is proposed to decide suitable control methods by making use of quasi-steady-state time-series (QSTS) software …

Intra-Day Solar Irradiance Forecasting For Remote Microgrids Using Hidden Markov Model, Abhilasha Bajracharya

Electronic Theses and Dissertations

Accurate solar irradiance forecasting is the key to accurate estimation of solar power output at any given time. The accuracy of this information is especially crucial in diesel-PV based remote microgrids with batteries to determine the set points of the batteries and generators for their optimal dispatch. This, in turn, is related directly to the overall operating cost because both an overestimation and an underestimation of the irradiance means additional operating costs for either suddenly ramping up the backup resources or causing under-utilization of the available PV power output. Accurately predicting the solar irradiance is not an easy task because …