Date of Award

2019

Document Type

Open Access Dissertation

Degree Name

Doctor of Philosophy in Mechanical Engineering-Engineering Mechanics (PhD)

Administrative Home Department

Department of Mechanical Engineering-Engineering Mechanics

Advisor 1

Dr. Gordon G. Parker

Committee Member 1

Dr. Jason R. Blough

Committee Member 2

Dr. Wayne W. Weaver

Committee Member 3

Dr. John E. Beard

Abstract

The US military is moving toward the electrification of many weapon systems and platforms. Advanced weapon systems such as high energy radar, electro-magnetic kinetic weapons and directed energy pose significant integration challenges due to their pulsed power electrical load profile. Additionally, the weapons platforms, including ships, aircraft, and vehicles can be studied as a mobile microgrids with multiple generation sources, loads, and energy storage. There is also a desire to extend the mission profile and capabilities of these systems. Common goals are to increase fuel efficiency, maintaining system stability, and reduce energy storage size as typically required to enable pulsed load devices. To achieve these goals, there is an opportunity to optimize system performance by considering system wide exergy, a measure of the useful energy within the system. By studying exergy, systems with multi-physical coupling, as with electrically pulsed devices that require cooling, the system can be optimized holistically. While numerous optimization approaches exist, many focus on the long term, hours to days, energy management problem. Furthermore, advance control strategies such as the Hamiltonian Surface Shaping Power Flow Controller (HSSPFC) require feedforward operating points about which storage is actuated to maintain stability. Storage size can be reduced by combining the HSSPFC with exergy based optimization strategies designed for sub-second update rates. In this dissertation, several numerical and closed form/numerical hybrid optimization strategies were developed where speed of solution was explored vs. microgrid asset size, in non-realtime simulation. Then an exergy based optimization strategy was combined with the HSSPFC on a three bus networked microgrid model using average switch mode models, pulse loading, and a thermal system. The three bus model was then extended to a co-simulation on Hardware-in-the-loop (HIL) using an Opal- RT OP5700 and Typhoon HIL 600 realtime simulators, where the optimization was executed asynchronously through UDP Ethernet communication. The storage utilization was reduced by orders of magnitude when comparing two cases of optimized vs. non-optimized generation settings. Bus voltage regulation was within 5 % where there was a trade off between optimization update rate, transient regulation, and storage utilization. Contributions of this work are summarized as follows. An exergy based, asynchronous, optimization strategy was developed to work in concert with the HSSPFC strategy where sub-second update rates were achieved. A co-simulation test bench was developed to allow the study of advanced control strategies through the use of multiple realtime HIL simulators. The methodology for integrating the HIL simulators is given including wiring, calibration, signal scaling, and implementation specific details. An on-line optimization strategy was also developed to interact with the HIL system and used for determining power converter duty cycle biases.

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