Available Research Assistantships
Initiated September 26, 1997
Graduate student research opportunities, including thesis/dissertation projects and several half-time research assistantships (RAs), are available immediately on Navy- and industry-sponsored projects involving modeling, simulation, and control of power electronic converters and converter-based power systems. Power electronic device technology and packaging are advancing to the point that it is now realistic to consider the design and deployment of so-called Integrated Power Systems, in which all energy sources and loads are interfaced to a distribution network through power converters. In particular, semiconductor devices capable of switching several hundred amperes against several thousand volts at frequencies above 20 kHz can support converter-based distribution systems that are superior in dynamic response, size/weight, and reliability when compared to the electrical power and hydraulic actuation systems used presently in many vehicular and industrial systems. Unfortunately, research and development in device technology has, to some extent, outpaced research and development in converter and system architectures that can make optimal use of the devices. This discrepancy is being addressed in the following projects:
Modeling, Control, and Implementation of Soft-Switching Power Converters
This project centers on the design of novel zero-voltage/zero-current power converter topologies and switching control strategies that provide high efficiency and low total harmonic distortion. The design process includes basic analysis, modeling and simulation using commercial and in-house tools, and prototyping of a converter power stage and DSP-based controller.
Only students with a background in power electronics will be considered for a half-time RA.
Analysis of Nonlinear Harmonic Interaction between Switching Power Converters and Networks.
Generally, design specifications for vehicular systems and distributed power supplies call for the various converters to interact only through modes at the fundamental power frequency. This approach simplifies theoverall design specification but often leads to overlconservative implementations having large electrical components that "decouple" the converters and network at harmonic frequencies. Analytical and control methods to estimate and mitigate deleterious harmonic interaction without use of decoupling components are being investigated in this project.
Only PhD students with a strong mathematical background in signals and systems will be considered for two three-year, half-time RAs.
Object-Oriented Design & Programming for Power System Design Tools
The design and assessment of large-scale, converter-based power systems is presently complicated by the lack of computer-aided-engineering tools that are well suited for these systems. In particular, present tools such as SPICE, EMTP, and transient stability codes do not address the special characteristics of these systems and their design problems, which include: mathematical stiffness; persistent excitation of fast dynamics due to switching; both time- and state-dependent changes in structure; independent, proprietary development of component models and architectures; component model loading effects; etc. Successful research and development of new tools to accommodate these characteristics will require the fusion of basic mathematical modeling and the latest software engineering techniques.
Only students having a background in power electronics or power system modeling and/or in object-oriented design & programming (preferably in C++ using Rogue Wave tools.h++) will be considered for two two-year, half-time RAs.