Date of Award

2016

Document Type

Open Access Dissertation

Department

Electrical Engineering

Sub-Department

College of Engineering and Computing

First Advisor

Enrico Santi

Abstract

Recent advances in semiconductor technology, controls, and switching converter topologies have resulted in the increasing application of power electronics in power distribution systems. Power electronic enabled distribution systems have inspired a renewed interest in DC distribution architectures as an appealing alternative to traditional AC methods due to the significant performance and efficiency gains they offer. However, the notional power electronic based DC distribution system is a complex and extensively interconnected system consisting of multiple power converters. As a result, a number of system-level challenges related to stability arise due to interaction among multiple power converters. In addition, the power distribution system is likely to undergo configuration variations as the system is subject to component upgrades, changes in power sources and loading, and even contingency scenarios involving fault conditions. The design of this type of system is difficult due to the general lack of proper analysis tools and limited understanding of the problem.

To address these design challenges, an approach to control design that accounts for converter interactions and allows for impedance based control is proposed. The use of impedance monitoring via wideband impedance identification techniques provides interesting opportunities for the development of a robust and adaptive control strategy. Power converters within the system can be adaptively adjusted to track changes in the system bus impedance, enacting revised control strategies with the intent of stabilizing the system as its dynamics evolve over time.

Secondly, the use of Power Hardware-in-the-Loop (PHIL) simulation is investigated for early system testing. As parts of the distribution system become available in hardware, it is desirable that they be evaluated under realistic system conditions. PHIL allows for advanced studies to be performed on system interactions by virtually coupling a real-time software simulation of electrical components to a physical piece of hardware through the use of an interfacing amplifier and appropriate control algorithm. Use of a PHIL test platform allows for system interaction studies to be performed early on in hardware development and provides an enhanced ability to study potential system-level problems and develop suitable solutions. Wideband impedance identification is utilized to complement the PHIL simulation, providing additional characterization of the hardware under test as well as critical information that is used to ensure stability and fidelity of the PHIL simulation test bed.

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