Author ORCID Identifier

https://orcid.org/0009-0009-5749-0366

Date Available

7-9-2024

Year of Publication

2024

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department/School/Program

Electrical and Computer Engineering

First Advisor

Aaron M. Cramer

Abstract

Electric warships are involved in complex missions consisting of multiple simultaneous operations. In order to ensure mission success, future ships must be designed in a way that optimizes their performance in the presence of complex mission loads. The focus of this research is an effort to optimally control the performance of shipboard systems during missions involving multiple scenarios or vignettes. The evaluation of the performance of mission-oriented power systems is based on the degree to which these systems deliver power to the loads required to perform the mission at hand. The performance of such systems involves a dynamic interplay between the power systems, the mission, and the loads required to perform the mission. Evaluating the performance is fundamental in the design of such systems for future use, and this evaluation is advanced by formulating the evaluation as an optimal control problem. This formulation allows the dynamic interaction between the system and the mission to be considered directly and is a natural evolution of existing simulation-based methods. In this work, the proposed approach is demonstrated using a notional, but representative, set of system implementations and missions. Furthermore, examples of the types of system trade offs that can be considered using this approach are presented and discussed. In addition, the optimal control problem can be implemented using market-based control. Market-based control is an approach which can be used when the system becomes difficult to control and maintain using centralized approaches such as Markov decision process-based optimization. A key feature of market-based control is that it reduces a global optimization problem into a series of smaller local optimization problems (i.e., profit maximization) combined with finding the market clearing prices that result in market equilibrium (i.e., quantity supplied is equal to quantity demanded). The market clearing price is the price which results in an equilibrium between demanded and supplied resources. Finding the globally coordinating market-clearing prices is a root-finding problem. It is known that under sufficient conditions the market-clearing problem is equivalent to solving the global optimization problem. To enable market-based control of such systems, it is necessary that appropriate market-clearing algorithms exist that can locate the market-clearing prices that allow the system to operate at equilibrium. This work examines the numerical challenges of solving the root-finding problem of finding the market-clearing prices using traditional algorithms. A method has been proposed for solving the market clearing problem and its performance has been compared with the performances of traditional root-finding algorithms. Finally, the connection between various optimization approaches has been explored and validated with results.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2024.279

Funding Information

Funding Organization: Office of Naval Research (ONR) of the United States Navy

Grant Numbers: N00014-20-1-2816 and N00014-23-1-2824

Funding Year: 2021-2024

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