Melanie Johnson with adviser Patrick L. Chapman Corrosion damage to reinforcing steel plagues civil infrastructure in the United States and causes an estimated $6 to 10 billion of damage per year to bridge decks alone. Despite this cost, no reliable non-destructive testing method exists to detect the presence of corrosion or the rate at which […]
Design and Analysis of Pulse-Width Modulation Techniques for Spectrum Shaping
Xin Geng with adviser P.T. Krein Standard pulse-width modulation (PWM) provides the internal actuation for most control schemes for both dc-dc and dc-ac converters. Switching signals generated by standard PWM techniques are rich in harmonics, which may cause detrimental effects to the converter’s working environment. The concept of modifying harmonic characteristics of PWM signals to […]
Automated physics-based reduced-order modeling of electromechanical systems
Ali Davoudi with adviser P.L. Chapman Electromechanical systems are faced with many compromises in simulation speed, accuracy, and stability. Magnetic-domain components ought to be accurate over a wide dynamic range, but they are often represented by analytical models that suffer from unreliable gross approximations. Alternatively, physics-based high-order models are obtained from finite-element method (FEM) or […]
Dynamic modeling of multiple-input power converters
Yongxiang Chen with adviser Patrick L. Chapman Energy is supplied to systems with multiple energy sources through multiple-input power converters. A solar vehicle powered by a solar panel and a battery, for example, can use a two-input dc-dc converter controlled to simultaneously provide maximum power point tracking of the solar panel and steady output power […]
Optimization of power converters in portable energy sources
Nicholas Benavides with adviser Patrick L. Chapman Portable electronic devices have grown in number and complexity. Powering these devices with lightweight sources is a major research focus. Advanced technology energy sources such as fuel cells and combustion-based microturbines seek to supplant chemical batteries due to their theoretically high energy density. These sources typically do not […]
Behavioral Analysis of Various IGBT Structures under Hard and Soft Overcurrent Turn-off
Abhishek Banerjee with adviser P. T. Krein Protection of insulated gate bipolar transistors (IGBTs, which are used in high-voltage inverters for automotive and industrial motor-drive applications) from overcurrent and short-circuit current during operation is essential to ensure system reliability. Faults in electric machine drives result in the IGBTs carrying a current substantially higher than rated […]
ECE 431 – Electric Machines
ECE 431, Electric Machines, is an undergraduate class addressing theory and laboratory experimentation with three-phase power, power factor correction, single- and three-phase transformers, induction machines, dc machines, and synchronous machines. It also includes dynamic behavior of machines, stepping and reluctance machines, and electrostatic machines, as well as project work on energy control systems. The pictures […]
New Textbook in Electromechanics
Professors Philip Krein and Patrick Chapman have a contract with Oxford University Press to write a new textbook on electromechanics. The title is Electromechanics: The Science and Engineering of Electrical Forces and Motion. This will be the new textbook for ECE 431. In the first half the authors are going back to the basics, as […]
2007 Solar Decathlon (year 2)
Trishan Esram with adviser Patrick L. Chapman The UIUC Solar Decathlon house (Figure 10) is nearing completion and is slowly taking the shape of the predicted house, a rendering of which is shown in Figure 11. The interior electrical wiring of the house is scheduled to be finished by the end of July. The exterior […]
GaN-Based MESFET with Enhaced dc Performance Using Nonalloyed Ohmic Contacts and Molecular Beam Epitaxy
Huichan (Chandler) Seo with advisers Kyekyoon (Kevin) Kim and Patrick Chapman We previously achieved record-high peak drain current and maximum transconductance of GaN metal-semiconductor field-effect transistors (MESFETs) and extended the work to AlGaN/GaN high electron mobility transistors (HEMTs) using a selective-area-growth (SAG) technique with plasma-assisted molecular beam epitaxy (PAMBE). A KOH (heated potassium hydroxide) etching […]