Engineering Commons^™

Strategy For Predictive Control Of The Rectification Process Based On A Model Controller With A Given Forecast, Ildar Rafkatovich Sultanov

Chemical Technology, Control and Management

A method is being developed to optimize the generated controls for the multicomponent distillation process with prediction, based on predictive data with a moving horizon. The difference between this method and the classical modeling approach, in which the percentage of the degree of opening of valves installed on the output streams of the column is used as control actions, is that control occurs on the feedback principle. The proposed method is based on the use of a dynamic process model to optimize control actions in real time in order to achieve certain production targets. The essence of the MPC approach …

Existing Methods For Monitoring Power Autotransformers, Nurali Berdiyorovich Pyrmatov, Dilafruz Rustamjon Qizi Abdullabekova

Technical science and innovation

autotransformers, methods, diagnostics, efficiency, monitoring.Particular attention is given to analyzing the gas composition of transformer oil, which is a sensitive indicator of various defects such as thermal breakdown and heating. In addition, methods based on the measurement of external magnetic field strength are discussed. This technique provides a unique opportunity to detect magnetic anomalies associated with possible defects in the structural components of the transformer. The article emphasizes that successful monitoring requires an integrated approach, combining different techniques. The authors analyze the advantages and limitations of each method and offer practical recommendations for integrating these methods into maintenance systems. In …

Efficiency Study Of A Hybrid Ac/Dc House, Eunice Dominique Solomon Santiago

Master's Theses

With the proliferation of residential-scale renewable energy sources and DC loads, it has become attractive to use residential DC electrical system that could offer benefits over the legacy residential AC electrical system. The Hybrid AC/DC house provides a sustainable alternative to preexisting residential electrical system by having both AC and DC buses. The DC bus facilitates the connection from DC sources to DC loads, whereas the AC bus interfaces AC sources to AC loads. The study develops the equations to calculate losses based on a model consisting of four main components: Multiple-Input Single-Output (MISO) converter, AC-DC converter, inverter, and DC-DC …

Investigation Of Degradation Of Solar Photovoltaics: A Review Of Aging Factors, Impacts, And Future Directions Toward Sustainable Energy Management, Eklas Hossain

Electrical and Computer Engineering Faculty Publications and Presentations

The degradation of solar photovoltaic (PV) modules is caused by a number of factors that have an impact on their effectiveness, performance, and lifetime. One of the reasons contributing to the decline in solar PV performance is the aging issue. This study comprehensively examines the effects and difficulties associated with aging and degradation in solar PV applications. In light of this, this article examines and analyzes many aging factors, including temperature, humidity, dust, discoloration, cracks, and delamination. Additionally, the effects of aging factors on solar PV performance, including the lifetime, efficiency, material degradation, overheating, and mismatching, are critically investigated. Furthermore, …

Lightnet: A Novel Lightweight Convolutional Network For Brain Tumor Segmentation In Healthcare, Dongyuan Wu, Junyi Tao, Zhen Qin, Rao Asad Mumtaz, Jin Qin, Linfang Yu, Jane Courtney

Articles

Diagnosis, treatment planning, surveillance, and the monitoring of clinical trials for brain diseases all benefit greatly from neuroimaging-based tumor segmentation. Recently, Convolutional Neural Networks (CNNs) have demonstrated promising results in enhancing the efficiency of image-based brain tumor segmentation. Most current work on CNNs, however, is devoted to creating increasingly complicated convolution modules to improve performance, which in turn raises the computing cost of the model. This work proposes a simple and effective feed-forward CNN, LightNet (Light Network). Based on multi-path and multi-level, it replaces traditional convolutional methods with light operations, which reduces network parameters and redundant feature maps. In the …

Influence Of Site And System Parameters On The Performance Of Roof-Top Grid-Connected Pv Systems Installed In Harlequins, Belfast, Northern Ireland, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon, Desmond Lalor, Ciaran Mcnamara

Other Resources

The problem of energy scarcity has hit a global scale because of the dependency of most of the energy generation on non-renewable sources (e.g., fossil fuels). As in supply and demand laws, the lower the amount of energy provided, the more expensive it becomes, causing a major problem for the industry in general, which is dependent on it. These non-renewable energy sources contribute to environmental degradation effects and depletion of the ozone layer from the atmosphere. To reduce this effect, the use of renewable energy sources which is environmentally friendly has been on the growing index across the globe.

Solar …

Oxidative Efficiency Of Ozonation Coupled With Electrolysis For Treatment Of Acid Wastewater, Ze-You Hu, Feng-Yun Xiang, Ji-Qiang Mao, Ya-Lei Ding, Shao-Ping Tong

Journal of Electrochemistry

Establishment of an ozone-based advanced oxidation process (AOPs-O₃) for effective treatment of acid wastewater is an important and difficult task. The process of ozonation coupled with electrolysis (electrolysis-ozonation, E-O₃) has been reported to effectively degrade pollutants in neutral solution. We studied the efficiency of E-O₃ for degradation of acetic acid (HAc, an ozone inert chemical) in acid solution and found that E-O₃ had high oxidative efficiency at pH less than 3. For example, 52.2% of 100 mg·L-1 HAc could be removed by E-O₃ in 120 min at pH 1.0, but only 2.2% and …

Solar Air Heater With Breathable Matrix Absorber Made Of Metal Wire Tangle, Yu. K. Rashidov, J. T. Orzimatov

Scientific-technical journal

In the article, a physical and mathematical thermal model of the operation of a solar air-heating collector with an air-permeable matrix absorber made of a metal wire tangle is developed, and analytical solutions of the model for boundary conditions of the first and second kind are obtained.

Dc Bus Voltage Selection For A Grid-Connected Low-Voltage Dc Residential Nanogrid Using Real Data With Modified Load Profiles, Saeed Habibi, Ramin Rahimi, Mehdi Ferdowsi, Pourya Shamsi

Electrical and Computer Engineering Faculty Research & Creative Works

This study examines various low voltage levels applied to a direct current residential nanogrid (DC-RNG) with respect to the efficiency and component cost of the system. Due to the significant increase in DC-compatible loads, on-site Photovoltaic (PV) generation, and local battery storage, DC distribution has gained considerable attention in buildings. To provide an accurate evaluation of the DC-RNG's efficiency and component cost, a one-year load profile of a conventional AC-powered house is considered, and AC appliances' load profiles are scaled to their equivalent available DC appliances. Based on the modified load profiles, proper wiring schemes, converters, and protection devices are …

Assessment Of Cable Length Limit For Effective Protection By Z-Source Circuit Breakers In Dc Power Networks, Ruiyun Fu, Sagar Bhatta, Joseph M. Keller, Yucheng Zhang

Electrical & Computer Engineering Faculty Publications

This paper introduces groundbreaking research on how to assess the Cable Length Limit (CLL) to ensure effective protection by Z-source Circuit Breakers (ZCBs) in DC power networks. It has been revealed that the line parameters of power cables have a significant impact on the cutoff performance of ZCBs. The question of assessing the CLL has been raised as an unsolved problem. In this paper, a method of CLL assessment is proposed based on physical models and simulation tests. To verify the proposed method, two studies were performed to assess the Cable Length Limits depending on fault levels and power delivery …

Bi-Directional Dc-Dc Converter, John W. Hamlin, Oscar Ambriz, Luis Onofre

Electrical Engineering

This project was developed with the purpose of creating an efficient energy management system for the DC House project, with a centralized 12V battery system fed by a 48V Multiple Input Single Output Source (MISO). The energy management system will consist of a bidirectional DC-DC converter. During the day when the renewable sources produce enough energy to fulfill the load’s energy demand, the converter will make use of the excess energy by taking a 48V DC input and stepping it down to a 12V DC output in order to charge a 12V 100 Ah battery. When renewable sources can no …

Cascaded Linear Regulator With Positive Voltage Tracking Switching Regulator, Brandon K. Nghe

Master's Theses

This thesis presents the design, simulation, and hardware implementation of a proposed method for improving efficiency of voltage regulator. Typically, voltage regulator used for noise-sensitive and low-power applications involves the use of a linear regulator due to its high power-supply rejection ratio properties. However, the efficiency of a linear regulator depends heavily on the difference between its input voltage and output voltage. A larger voltage difference across the linear regulator results in higher losses. Therefore, reducing the voltage difference is the key in increasing regulator’s efficiency. In this thesis, a pre switching regulator stage with positive voltage tracking cascaded to …

Energy Efficiency In Cmos Power Amplifier Designs For Ultralow Power Mobile Wireless Communication Systems, Selvakumar Mariappan, Jagadheswaran Rajendran, Norlaili Mohd Noh, Harikrishnan Ramiah, Asrulnizam Abd Manaf

Turkish Journal of Electrical Engineering and Computer Sciences

Wireless communication standards keep evolving so that the requirement for high data rate operation can be fulfilled. This leads to the efforts in designing high linearity and low power consumption radio frequency power amplifier (RFPA) to support high data rate signal transmission and preserving battery life. The percentage of the DC power of the transceiver utilized by the power amplifier (PA) depends on the efficiency of the PA, user data rate, propagation conditions, signal modulations, and communication protocols. For example, the PA of a WLAN transceiver consumes 49 % of the overall efficiency from the transmitter. Hence, operating the PA …

Investigating The Efficiency Of Multithreading Application Programming Interfacesfor Parallel Packet Classification In Wireless Sensor Networks, Mahdi Abbasi, Milad Rafiee, Mohammad R. Khosravi

Turkish Journal of Electrical Engineering and Computer Sciences

This paper investigates the most appropriate application programming interface (API) that best accelerates the flow-based applications on the wireless sensor networks (WSNs). Each WSN include many sensor nodes which have limited resources. These sensor nodes are connected together using base stations. The base stations are commonly network systems with conventional processors which are responsible for handling a large amount of communicated data in flows of network packets. For this purpose, classification of the communicated packets is considered the primary process in such systems. With the advent of high-performance multicore processors, developers in the network industry have considered these processors as …

A Comparative Study On The Stability And Degradation Of Perovskite Solar Cells, Jyotiska Chakraborty

Masters Theses

This study aims to investigate the environmental factors that affect the performance and longterm stability of the perovskite solar cells (PSCs). PSCs are based on organo-metallic halides (perovskites) that act as a light-sensitive compound that produces excitons when placed under the light. However, PSCs have a limited operating lifetime due to the degradation of the perovskite layer. There are many factors like moisture, UV light, and temperature that lead to the degradation of the perovskite layer. From the literature review, it was found that the PSCs do not degrade with the presence of oxygen in a dry and dark environment. …

Cost Effective, Highly Efficient Wireless Power Transfer Systems For Ev Battery Charging, Amir Masoud Bozorgi

LSU Doctoral Dissertations

The impact of changing inner diameter of wireless power transfer (WPT) coils on coupling coefficient is studied. It is demonstrated that at a certain outer and inner coil diameter, turn space variation has minor effect on the coupling coefficient. Next, two compensation networks, namely primary LCC and secondary LCC, which offer load-independent voltage transfer ratio and zero voltage switching for WPT, are presented. For both compensation networks, the condition for having zero voltage switching operation are derived. In addition, load-independent voltage transfer ratio (VTR) frequencies are obtained and VTR at each frequency is derived. Then, required equations for calculation of …

Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir

Makara Journal of Technology

A solar cell is a device that absorbs light energy to generate electrical energy. A typical example of a solar cell is the quantum dot solar cell (QDSC), which consists of three main components: (i) fluorophore: the component that absorbs light and generates excited state electrons and holes, (ii) photoelectrode: the component that transports the excited state electron and prevents recombination of excited state electrons and holes, and (iii) electrolyte: the component that re-plenishes the vacancy left by the excited electron in the hole. Despite the increasing number of research in the QDSC field, to date, a device with significant …

Optical And Electrical Analysis Of Zno/Znte Micropillar Solar Cells, Sadia Binte Sohid

Master’s Theses

The prime focus of the energy-research community in recent times has been replacing fossil fuels with renewable energy. Therefore, photovoltaic research areas are rapidly expanding in this era. The purpose of this work is to compare three different structural ZnO/ZnTe solar cell types (planar, axial micropillar and radial micropillar). The best optical and electrical performance has been obtained by the radial junction (core-shell) ZnO/ZnTe micropillar solar cell due to its pillar structure and radial junction. The unique advantage of the radial junction micropillar is that the angle of the incident light and the carrier collection is orthogonal. Therefore, the pillar …

Comparative Study Of Power Semiconductor Devices In A Multilevel Cascaded H-Bridge Inverter, Kenneth Mordi

Graduate Theses and Dissertations

This thesis compares the performance of a nine-level transformerless cascaded H-bridge (CHB) inverter with integrated battery energy storage system (BESS) using SiC power MOSFETs and Si IGBTs. Two crucial performance drivers for inverter applications are power loss and efficiency. Both of these are investigated in this thesis. Power devices with similar voltage and current ratings are used in the same inverter topology, and the performance of each device is analyzed with respect to switching frequency and operating temperature. The loss measurements and characteristics within the inverter are discussed. The Saber® simulation software was used for the comparisons. The power MOSFET …

Evaluation Of Heat Efficiency Of Flat Solar Air Heaters, E.S. Abbasov, M.A. Umurzakova

Journal of Tashkent Institute of Railway Engineers

The article discusses the issues of increasing the thermal efficiency of flat solar air collectors. To achieve the goal, the authors propose to use methods of wall intensification of heat transfer (using the diffuser-confusor channels and surfaces with spherical depressions). In the article formulas for calculating the thermal efficiency and the relative thermal performance of the collectors are developed

Analysis Of Improved Multiphase Buck Converter, Usamah Riaz Ahmad, Scott Wu

Electrical Engineering

While the number of transistors per microprocessor is rapidly increasing, the power requirements of converters are getting more and more important. The amount of current is increasing, while at the same time the output voltage is steadily decreasing. Today’s boards are exceeding 100A, while the buck converters have their output voltage below 1 V. Due to these new power requirements, multiphase buck converters are becoming more popular. In addition, this topology is usually used with voltage regulator modules (VRM).

The TPS40090EVM-002 board was used as the original multiphase buck with an input voltage of 12 V and output voltage of …

Thermoelectrics And Thermoelectric Devices, Benjamin T. Erck

Senior Theses

The field of thermoelectrics has many applications, and more are found in everyday systems. From its current studies, it is apparent that improving the figure of merit zT (which defines a good thermoelectric material) is important in the effectiveness of power generation. Another important part of thermoelectrics is the duality of these devices. They can both move heat and generate power, depending on their role in the system. In this thesis research, a process was made to test these thermoelectric relationships for a few Peltier devices in order to understand their efficiencies and what systems they can be applied to.

Assisted Switched Reluctance Machines, Amy Robinson

Honors Scholar Theses

Switched reluctance machine (SRM) modifications in both control schemes and physical design have been steadily increasing in academia to improve machine performance. Assisted switched reluctance machines (ASRMs) are a type of design modification for SRMs. Permanent magnets (PMs) and electromagnetic DC coils (DCC) are being added to the SRM to improve its torque output and overall efficiency. The choice for the design modification has been evolving throughout the decades. The focus has shifted from adding DCC to ASRM to adding PMs to ASRMs. This paper reviews the research trends of ASRMs and includes an analysis of the modified stator yoke …

Efficiency Improvement Of Fault-Tolerant Three-Level Power Converters, Ramin Katebi, Jiangbiao He, Waqar A. Khan, Nathan Weise

Electrical and Computer Engineering Faculty Research and Publications

Fault-tolerant power converters play a critical role in the transportation electrification. However, fault-tolerant operation, high efficiency, and low cost usually result in design criteria that have conflicting constraints and goals. The majority of the fault-tolerant power converter topologies presented in the literature confirm these conflicts. In this paper, three types of fault-tolerant neutral-point clamped (NPC) converters are investigated. Various modulation strategies are explored to reduce the losses of the redundant phase leg. The simulation and experimental results show that the Switching Frequency Optimal Phase opposition Disposition modulation strategy is the most effective approach in minimizing the losses in the redundant …

Fundamental Efficiency Limit Of Passive Non-Magnetic Self-Interference Suppression In Full-Duplex Radios, Adam Narbudowicz, Giuseppe Ruvio, Max Ammann, Nicola Marchetti

Conference Papers

Passive non-magnetic self-interference suppression circuits are currently used as first stages of complex full-duplex radio systems that allow simultaneous reception and transmission within the same channel. This paper introduces the upper efficiency limit for such circuitry. It is demonstrated that for these devices it is not feasible to have simultaneously high efficiency, good transmitter-to-receiver isolation and same propagation channel for transmission and reception. More specifically, the maximum efficiency for most typical case cannot exceed 50% if good isolation is obtained.

A Study Of The Sensitivity Of Energy Conversion Efficiency To Load Variation In Class-E Resonant Power Inverter, Richard Samuel Jennings

Electrical & Computer Engineering Theses & Dissertations

In this thesis the sensitivity of energy conversion efficiency (ECE) and output power of a class-E resonant inverter under variable resistive and inductive load assignments is examined for wireless power transfer (WPT) applications. By performing simulation and mathematical analysis, it was found that the on-resistance of the switching device has minor effect on the design’s efficiency. Additional comparisons between the simulation and mathematical analysis show reasonable output power and ECE load variation performance for the design, but with unique load impedances where zero voltage switching (ZVS) and zero derivative switching (ZDS) are achieved. These comparisons also expose inaccurate mathematical assumptions. …

On The Use Of Wheeler Cap For Mimo Antennas, Florian Reher, Adam Narbudowicz, Max Ammann, Dirk Heberling

Conference Papers

A new equivalent circuit based Wheeler Cap method to calculate MIMO efficiency is introduced. The method works without the necessity for interpolation by avoiding concur of resonating and cavity modes. The method is tested with a set of three differently correlated MIMO antennas. Results are compared with the recently proposed quality factor method for MIMO antennas and efficiency data from spherical near field measurements.

Automatic Power Management For Instructional Computers At Humboldt State University: A Calculation Of Potential Energy Savings And Greenhouse Gas Emissions Reductions, Nicholas F. Flenghi

Projects

Computers consume an estimated 5,610 GWh per year in California alone. Much of that energy is consumed by computers that are not being used. In this project, detailed user login data are used to estimate the energy consumption of instructional computers at Humboldt State University (HSU) over the course of one semester. The data are also used to estimate the potential energy savings from automating the shutdown process. Potential cost savings and greenhouse gas (GHG) emissions reductions resulting from implementing an automatic-shutdown power management plan are also calculated.

There are approximately 1,000 computers used for teaching and learning purposes at …

Towards The Scalability And Hybrid Parallelization Of A Spatially Variant Lattice Algorithm, Henry Roger Moncada Lopez

Open Access Theses & Dissertations

The purpose of this research is to design a faster implementation of the spatially variant algorithm that improves its performance when it is running on a parallel computer system.

The spatially variant algorithm is used to synthesize a spatially variant lattice for a periodic electromagnetic structure. The algorithm has the ability to spatially vary the unit cell orientation and exploit its directional dependencies. The algorithm produces a lattice that is smooth, continuous and free of defects. The lattice spacing remains strikingly uniform when the unit cell orientation, lattice spacing, fill fraction and more are spatially varied. This is important for …

Highly Efficient Three-Phase Three-Level Multilevel Inverter Employing Different Commutation Strategies, Ammar Masaoud, Hew Wooi Ping, Saad Mekhilef, Hamza Belkamel

Turkish Journal of Electrical Engineering and Computer Sciences

This paper introduces a new three-phase three-level voltage source inverter. The proposed topology constitutes the conventional three-phase two-level inverter with three bidirectional switches. For purpose of generating the appropriate switching gate signals, two different commutation strategies are suggested and analyzed. A comparison between both strategies in terms of power losses and efficiency are presented. To ensure the feasibility of the proposed configuration with its suggested commutation strategies, the prototype of the proposed inverter was manufactured and the experimental results are given.