Electrical and Computer Engineering Commons^™

Mission Profile Effects On Automotive Drivetrain Electronics Reliability: Modeling And Mitigation, Bakhtiyar Mohammad Nafis

Graduate Theses and Dissertations

The reliability of electronic devices is dependent upon the conditions to which they are subject. Temperature variations coupled with differences in thermal expansion between bonded materials results in thermomechanical stresses to build up, which can instigate failure in the interconnects or other critical regions. With the move towards electrification in the automotive industry, there is the increasingly important consideration of powertrain electronics reliability, the pertinent conditions being governed by the drive cycle or mission profile of the vehicle. The mission profile determines the power dissipated by the electronic devices, which determines the peak and mean temperature, temperature swing and the …

Characterization Of Wide-Bandgap Sic Field Effect Transistors And Their Active Gate Driving Circuit In High Power Applications, Arijit Sengupta

Legacy Theses & Dissertations (2009 - 2024)

Silicon Carbide (SiC) devices are slowly becoming one of the most reliable choices for high power density, high switching frequency applications with higher efficiency than Gallium Nitride (GaN) and Silicon (Si) devices. For a wide range of applications, such as Electric Motor Drives, Switching Power Supplies, and Renewable Energy Circuits, SiC devices are being tested and are found to yield prominent results.In this research, the characterization of two similarly rated commercially available SiC devices - a trench Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and a cascoded Junction Field Effect Transistor (JFET) are done. It is followed by a comparative analysis of both …

Analysis And Design Of 3-Phase Unfolding Based Ac-Dc Battery Chargers, Rees R. Hatch

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This thesis presents the analysis and design of high-efficiency battery chargers for heavy duty EV applications. The rise in popularity of the electric vehicles (EVs) due to their increased efficiency over conventional internal combustion engines, has driven the need for more battery charging infrastructure. Furthermore, heavy duty vehicles are also being converted to electric to fill needs such as public transportation via bus fleets as well as cargo delivery via semi-trucks. Such heavy duty vehicles require more energy than personal transportation vehicles and thus require larger battery packs. To charge heavy duty battery packs in the same amount of time …

Zero Voltage Switching Hybrid Voltage Divider Converter, Timothy Jeong

Master's Theses

This project proposes a new hybrid voltage divider DC-DC converter that utilizes switching capacitors and inductors to produce zero voltage switching (ZVS) at the turn on state of its switches. By achieving ZVS, the switching losses are significantly reduced; thus, increasing the overall efficiency of the converter at various loads. The goal for this thesis is to perform analysis of the operation of the converter, derive equations for sizing the main components, and demonstrate its functionality through computer simulation and hardware prototype. Results of the simulation and hardware testing show that the proposed converter produces the desired output voltage while …

An Accurate And Efficient Electro-Thermal Compact Model Of Sic Power Mosfet Including Third Quadrant Behavior, Arman Ur Rashid

Graduate Theses and Dissertations

Due to narrower bandgap and lower critical electric field, silicon (Si) power devices have reached their limit in terms of the maximum blocking voltage capability. Exploiting this limitation, wide bandgap devices, namely silicon carbide (SiC) and gallium nitride (GaN) devices, are increasingly encroaching on the lucrative power electronics market. Unlike GaN, SiC devices can exploit most of the established fabrication techniques of Si power devices. Having substrate of the same material, vertical device structures with higher breakdown capabilities are feasible in SiC, unlike their GaN counterpart. Also, the excellent thermal conductivity of SiC, compared to GaN and Si, let SiC …

Controller Modeling And Stability Analysis Of Multiple Input Single Output Dc-Dc Converter, Astha Adhikari

Master's Theses

This thesis entails the stability analysis of the Multiple Input Single Output (MISO) DC-DC converter developed for the DC House Project at Cal Poly. A frequency domain control system model of the MISO converter was designed and constructed using MATLAB Simulink. Transfer functions were derived and modeled for each stage of the converter to best fit the converter circuit system used in the original MISO circuit. Stability metrics such as overshoot, undershoot, rise time, phase margin and gain margin were measured to evaluate and analyze the stability of the converter. These metrics were measured with the original model including the …

Design And Evaluation Of High Power, High Efficiency And High Power Density Motor Drives For More Electric Aircrafts, Zhao Yuan

Graduate Theses and Dissertations

More-electric aircraft (MEA) is an attractive concept as it can reduce carbon dioxide emission, relieve fossil-fuel consumption, improve the overall efficiency of aircraft, and reduce the operational costs. However, it poses substantial challenges in designing a high-performance motor drive system for such applications. In the report of Aircraft Technology Roadmap to 2050, the propulsion converter is required to be ultra-high efficiency, high power density, and high reliability. Though the wide band-gap devices, such as the Silicon-carbide based Metal Oxide Silicon Field Effect (SiC-MOSFET), shows better switching performance and improved high-temperature performance compared to the silicon counterparts, applying it to the …

Methods For Dynamic Stabilization, Performance Improvement, And Load Power Sharing In Dc Power Distribution Systems, Hessamaldin Abdollahi

Theses and Dissertations

Modern DC power distribution systems (DC-PDS) offer high efficiency and flexibility which make them ideal for mission-critical applications such as on-board power systems of All-Electric ships, electric vehicles, More-Electric-Aircrafts, and DC Microgrids. Despite these attractive features, there are still challenges that need to be addressed. The two most important challenges are system stability and load power sharing. The stability and performance are of concern because DC-PDS are typically formed by the interconnection of several feedback-controlled power converters. The resulting interactions can lead to destabilizing dynamics. Likewise, in a DC-PDS there are several source converters that are operating in parallel to …

Conducted Emi Mitigation In Power Converters Using Active Emi Filters, Balaji Narayanasamy

Graduate Theses and Dissertations

Wide bandgap devices enable high power density power converters. Despite the advantages of increased switching frequency, the passive components are still a major bottleneck towards enabling high power density. Among the passive components in the converter, the passive EMI filters are unavoidable to ensure compliance with conducted EMI standards. Active EMI filters help reduce the volume of the passive components and have been around for three decades now. Firstly, this work presents a summary of all the different active EMI filters based on the type of noise-sensing, noise-processing, the type of active circuits used and the type of control methods. …

Miso Dc-Dc Farmbot, Quyen Thi Nguyen, Brian Armijo, Astha Adhikari

Electrical Engineering

Making use of renewable energy directly from the location of production requires converting source power into usable power. The specific scope of this project focuses on the DC to DC conversion within a user friendly universal farmbot system. Since renewable sources vary widely in voltage and current, a wide input-range DC to DC converter is desired. Physical isolation, long lifespan, and adverse weather requires safe and reliable final product specifications. The goal of a very wide customer base drives the need for a product that does not require tinkering to get working, but to be usable out of the box …

Multiple Input Single Output Converter With Uneven Load Sharing Control For Improved System Efficiency, Kristen Y. Chan

Master's Theses

This paper presents the development and study of multiple-input single-output converter (MISO) for the DC House project that utilizes a controller to maximize the overall converter’s efficiency. The premise of this thesis is to create uneven load current sharing between the converters at different loading conditions in order to maximize the efficiency of the overall MISO converter. The goal is to find a proper ratio of current from each converter to the total load current of the MISO system to achieve the greatest efficiency. The Arduino microcontroller is implemented to achieve this goal. The design and operation of the MISO …

Cascaded Linear Regulator With Negative Voltage Tracking Switching Regulator, Ernest Lei

Master's Theses

DC-DC converters can be separated into two main groups: switching converters and linear regulators. Linear regulators such as Low Dropout Regulators (LDOs) are straightforward to implement and have a very stable output with low voltage ripple. However, the efficiency of an LDO can fluctuate greatly, as the power dissipation is a function of the device’s input and output. On the other hand, a switching regulator uses a switch to regulate energy levels. These types of regulators are more versatile when a larger change of voltage is needed, as efficiency is relatively stable across larger steps of voltages. However, switching regulators …

Energy Management Of Dynamic Wireless Power Transfer Systems For Electric Vehicle Applications, Ahmed N. Azad

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Wireless power transfer is a method of transferring electric power from a transmitter to a receiver without requiring any physical connection between the two. Dynamic Wireless Power Transfer (DWPT) entails having the transmitters buried under the roadway and the receiver unit being installed on the Electric Vehicle (EV). In this method, EVs are charged while driving over the transmitters as they receive bursts of electric energy at the time of significant alignment between transmitters and receivers. Compared to the stationary charging method which involves parking the EV for long hours for a full charge, the dynamic charging method (i.e., DWPT) …

Very Low Power Cockcroft-Walton Voltage Multiplier For Rf Energy Harvesting Applications, Trace Langdon

Electrical Engineering Undergraduate Honors Theses

A device was required that could harvest the electromagnetic energy present in ambient radio frequency (RF) signals. A part of this device must convert the AC RF signal received by the antenna into a DC signal that can be used in an embedded application. Since the RF signal amplitude is small, it must first be amplified and rectified to become a usable signal. The Cockcroft-Walton voltage multiplier is a subsystem of the design which ideally converts a 100 mV AC signal coming from the antenna to a 350 mV DC signal. The output of the voltage multiplier is used to …

Gating Methods For High-Voltage Silicon Carbide Power Mosfets, Audrey Dearien

Graduate Theses and Dissertations

The objective of this thesis is to assess the challenges associated with driving Silicon Carbide (SiC) power devices, and to compare the potential gate drive methods for these devices which address those challenges. SiC power devices present many benefits that make them suitable for next generation automotive, power utility grid, and energy management applications. High efficiency, increased power density, and reliability at high-temperatures are some of the main benefits of SiC technology. However, the many challenges associated with these devices have prevented their adoption into industry applications. The argument is made in this thesis that the gate driver is a …

Flexible Custom Electric Skateboard, Caleb Adam Kelsay

Electrical Engineering

At Cal Poly traveling long distances only accessible by foot such as across campus or from the car park to class can be tiring and time-consuming. While not physically demanding, the trek consumes time in our tight college life schedule. To improve our time efficiency this project provides a relatively lightweight, powered solution to quickly and effectively travel long distances while maintaining full control and safety even on hills, a current limitation of traditional skateboards.

This electric skateboard includes the battery capacity to travel all around campus on a single charge with a compact and flexible skateboard design that provides …

Chaotic Behavior In High-Gain Interleaved Dc-Dc Converters, Ahmad Alzahrani, Pourya Shamsi, Mehdi Ferdowsi, Cihan H. Dagli

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, chaotic behavior in high gain dc-dc converters with current mode control is explored. The dc-dc converters exhibit some chaotic behavior because they contain switches. Moreover, in power electronics (circuits with more passive elements), the dynamics become rich in nonlinearity and become difficult to capture with linear analytical models. Therefore, studying modeling approaches and analysis methods is required. Most of the high-gain dc-dc boost converters cannot be controlled with only voltage mode control due to the presence of right half plane zero that narrows down the stability region. Therefore, the need of current mode control is necessary to …

The Zephyr Charge: A Wind-Powered Usb Charger, James Dean Carson, John Pina Lopez Iii

Electrical Engineering

The Zephyr Charge project is to design and build a cell phone charger using a small wind turbine generator that can be useful to the fishermen community, namely fishermen of third world countries. The generator will output to USB for ease of charging capability. The size of the whole system should be light enough to move around, and the turbine itself will be mountable onto an edge of a wall. The goal of this project is to design and build a compact and easy to use cell phone charger, which is also efficient.

In order to be a practical product, …

Comparative Study Of Three Types Of Inverters Based On The Output Total Harmonic Distortion, Paterrson Thomas

Masters Theses

"In this thesis, three cases of power electronic inverters are taken into consideration to analyze their performance in terms of total harmonic distortion in their output voltage and output current. Firstly, a single H-bridge inverter is simulated. Staircase switching technique is used to generate the gating pulses for the switches. Only one switch is made to toggle for every half cycle. The fundamental harmonic component of the desired output voltage is considered to be 120 V. Secondly, the same topology is used with a Bipolar PWM gating technique. The switching frequency of the carrier wave is 33*60 Hz. Thirdly, a …

An Energy Based Minimum-Time Optimal Control Of Dc-Dc Converters, Amir Zandnia

Dissertations, Master's Theses and Master's Reports - Open

Time-optimal response is an important and sometimes necessary characteristic of dynamic systems for specific applications. Power converters are widely used in different electrical systems and their dynamic response will affect the whole system. In many electrical systems like microgrids or voltage regulators which supplies sensitive loads fast dynamic response is a must. Minimum time is the fastest converter to compensate the step output reference or load change. Boost converters as one of the wildly used power converters in the electrical systems are aimed to be controlled in optimal time in this study. Linear controllers are not able to provide the …

Advanced Control Of Grid-Connected Multilevel Power Electronic Rectifiers, Sangin Lee

Doctoral Dissertations

"Multilevel power electronic converters have been gaining attention due to their ability to supply high amounts of power and to handle high voltage levels. In this dissertation, grid connected AC-DC rectifier application is investigated with different topologies and control scheme.

At first, neutral point clamped (NPC) rectifier is employed to transfer power from the grid to the load. The NPC rectifier has two capacitors in order to build multilevel output voltage. However, it causes voltage unbalancing problem. Therefore, the new method has been proposed to regulate each capacitor voltage at the same voltage level. Experimental results show that it is …

Unbalanced Current Static Compensator, Manuel Antonio Sanchez Tejada

Graduate Theses and Dissertations

The objective of this thesis is to present and evaluate a solution to the unbalanced current issue that can be found in three-phase electrical power grids. The solution is named unbalanced current static compensator (UCSC) and has the goal of balancing the currents at the source in order to mitigate adverse issues such as of negative- and zero-sequence currents that are generated by three-phase current unbalances.

The solution topology consists of three single-phase H-bridge converters that are controlled through an algorithm working in the d-q frame of reference. The algorithm is divided in three different stages: the phase synchronization and …

Smart Wall Outlet Design And Implementation For The Dc House Project, Kevin Roy Mendoza

Master's Theses

Most everyday AC appliances are designed to operate off of 120V coming from the wall outlet in our homes. This voltage is a standard set from our established infrastructure. Unlike AC devices, DC devices do not have any set standard of voltage they all will run off of. This presents a problem for the DC house as the various loads that will be used will have different required input voltages. One set voltage for a wall outlet will not suffice for the DC House. This Smart Wall Outlet is designed with a DC-DC converter that will have its output voltage …

Bipolar Pulse Width Modulation Inverter, Xin Chen, Ryan Harada

Electrical Engineering

The project entails the design of an improved PWM inverter circuit for the inverter lab experiment in the introductory power electronic course. The improved PWM inverter uses bipolar switching with a half bridge control circuit. The inverter utilizes two ICL8038 chip to generate both the control and carrier signals. The improved inverter enhances the system's portability, protection and is easy to understand from the prior design. The improved PWM inverter provides AC variable single phase 65 Hz AC output voltage from DC input signal. The finished product will be used specifically in the EE 410 laboratory course.

Human-Powered Swing Generator, Danny Cai, Timothy Lai, Brandon Wong

Electrical Engineering

Many developing countries lack sufficient resources to provide enough electricity for every family to live with a satisfying level of comfort and convenience. Our project proposes a solution that provides families with an alternative access to electricity using a playground swing. This project addresses the design and construction of the Human-Powered Swing Generator, which converts mechanical energy to electrical energy for charging a battery. The charged battery serves as a source of DC energy for potential DC purposes, such as charging a cell phone.

Emc In Power Electronics And Pcb Design, Chentian Zhu

All Dissertations

This dissertation consists of two parts. Part I is about Electromagnetic Compatibility (EMC) in power electronics and part II is about the Maximum Radiated Electromagnetic Emissions Calculator (MREMC), which is a software tool for EMC in printed circuit board (PCB) design. Switched-mode power converters can be significant sources of electromagnetic fields that interfere with the proper operation of nearby circuits or distant radio receivers. Part I of this dissertation provides comprehensive and organized information on the latest EMC developments in power converters. It describes and evaluates different technologies to ensure that power converters meet electromagnetic compatibility requirements. Chapters 2 and …

Impedance Extraction By Matlab/Simulink And Labview/Multisim, Jen-Pin Lin

USF Tampa Graduate Theses and Dissertations

This thesis studies the techniques of small-signal impedance measurement in three-phase power systems. Stability issue has become critically important since power electronics are highly applied in power distribution and conversion systems. Controlled output systems cause the risk of instability. In order to obtain the impedance model, an impedance extraction in D-Q reference frame algorithm is developed. This paper also applied Interpolated Fast Fourier Transform to increase accuracy of impedance model. Based on the voltage injection, Phase-Locked Loop, Park Transform, D-Q reference frame, and IPFFT. Three-phase system has been realigned on D-Q coordinate and impedance model is extracted in this form. …

State Of Charge Based Droop Surface For Optimal Control Of Dc Microgrids, Arthur John Jones

Dissertations, Master's Theses and Master's Reports - Open

For a microgrid with a high penetration level of renewable energy, energy storage use becomes more integral to the system performance due to the stochastic nature of most renewable energy sources. This thesis examines the use of droop control of an energy storage source in dc microgrids in order to optimize a global cost function. The approach involves using a multidimensional surface to determine the optimal droop parameters based on load and state of charge. The optimal surface is determined using knowledge of the system architecture and can be implemented with fully decentralized source controllers. The optimal surface control of …

Impedance Estimation Using Randomized Pulse Width Modulation And Power Converters, William M. Mccoy

Theses and Dissertations

With the adoption of technologies such as alternative energy production, DC power grids, and electric vehicles, the use of high power switching converters has seen a dramatic increase. These power converters serve many rolls such as grid-tied inverters in solar farms, high power charging for electric vehicles, motor drives for industrial applications, and DC links in transmission systems. With the increased prevalence of such devices, it is only natural to attempt to optimize their operation. As with any level of converter, it is desirable to have accurate control over the generated voltages and currents. Often, these controllers implement some form …

Local Digital Control Of Power Electronic Converters In A Dc Microgrid Based On A-Priori Derivation Of Switching Surfaces, Bibaswan Banerjee

Dissertations, Master's Theses and Master's Reports - Open

In power electronic basedmicrogrids, the computational requirements needed to implement an optimized online control strategy can be prohibitive. The work presented in this dissertation proposes a generalized method of derivation of geometric manifolds in a dc microgrid that is based on the a-priori computation of the optimal reactions and trajectories for classes of events in a dc microgrid. The proposed states are the stored energies in all the energy storage elements of the dc microgrid and power flowing into them. It is anticipated that calculating a large enough set of dissimilar transient scenarios will also span many scenarios not specifically …