Modeling, analysis, and stability assessment of multi-converter power electronic systems.

摘要

As the power systems evolve to contain more and more solid-state devices, a new type of power system emerges. We call this solid-state, silicon rich, silicon intensive, power electronics based, or, as is named in this dissertation, multi-converter power electronic systems. In these systems, solid-state power converters such as DC/DC choppers, DC/AC inverters, AC/AC cycloconverters, and AC/DC rectifiers are extensively used in source, load, and distribution subsystems to provide power at different voltage levels and both DC and AC forms. Most of the loads are also in the form of power electronic converters and motor drives.; These systems have a broad variety of applications from small multi-converter systems such as automotive power systems, Electric and Hybrid Electric Vehicles (EV & HEV), advanced industrial electrical systems, telecommunications, and terrestrial computer systems with a few converters to large systems such as International Space Station (ISS), spacecraft, modern aircraft, submarine, and More Electric Ship (MES) power systems with many converters. Furthermore, these unconventional power systems have unique characteristics, dynamics, and stability problems that are just beginning to be appreciated. In this dissertation, we take a closer look at multi-converter power electronic systems, address the fundamental problems faced in these systems, and offer new tools for their solutions.; The purpose of this dissertation is to present a conceptual study of these unconventional power systems. Furthermore, we propose a modular approach for the modeling and simulation of these systems based on the generalized state space averaging technique. Use of this method, in addition to simplifying the analysis of the systems, reduces the required computation time and computer memory considerably.; This dissertation also presents an assessment of the stability analysis of multiconverter power electronic systems. Limitations and drawbacks of the present stability analyzing techniques and recommendations on methods of stability analysis are provided. Different instabilities and related dynamics are introduced as well. Furthermore, different stabilizing controls such as load impedance control and feedback linearization techniques are introduced and designed. At last, recommendations for the design of multi-converter systems to avoid negative impedance instability are provided. Guidelines to design proper multi-converter architectures are also established.