Doctoral Dissertations

Keywords and Phrases

Bidirectional Switches; Dual Active Bridge; Dynamic System Modeling; Generalized Average Modeling; Soft Switching; Solid State Transformers

Abstract

"The Solid-State Transformer (SST) is gaining attention as an alternative to conventional iron-core transformers in the power electronic community. The power industry's increasing demands for smaller size, higher efficiency, and greater energy density have made the SST an attractive option. Among various power electronic converter topologies, the Dual Active Bridge (DAB) has become popular for its bidirectional power flow capability and galvanic isolation, primarily in the DC application space. Advancements in semiconductor technologies have introduced new bidirectional switches, opening avenues for novel SST topologies. This research investigates the application of the DAB as a single-stage SST and focuses on advancements in modeling, design, and control for ac-ac applications. Analytical expressions for phase shifts are derived, leading to the formulation of a design rule. Additionally, a real-time DSP based soft-switching algorithm is developed to meet the primary requirement of high-efficiency designs. The integration of DAB inductance in the transformer enhances energy density. However, dynamic modeling of the ac-ac DAB converter poses challenges, as it exhibits two distinct excitation frequencies that current modeling methods cannot adequately capture. To address this, an improved version of the Generalized Averaged Modeling (GAM) technique, called Extended-GAM (EGAM), is introduced. EGAM incorporates the multiplication of Double Fourier Series (DFS) signals, enabling the capture of multiple harmonics in converter dynamics. The algorithm is validated through harmonic truncation observations and a case study involving a single-phase inverter with LC filters. The EGAM technique is successfully applied to the ac-ac DAB converter, effectively handling its dynamic behavior and overcoming challenges posed by switching terms. Extensive simulations and hardware experiments validate the accuracy and effectiveness of the proposed EGAM modeling approach. These advancements contribute to precise modeling, efficient power flow control, and enhanced design of the ac-ac DAB converter, showcasing its potential as a Solid-State Transformer"--Abstract, p. iv

Advisor(s)

Kimball, Jonathan W.

Committee Member(s)

Ferdowsi, Mehdi
Shamsi, Pourya
Zawodniok, Maciej Jan, 1975-
Park, Jonghyun

Department(s)

Electrical and Computer Engineering

Degree Name

Ph. D. in Electrical Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2023

Pagination

xiii, 104 pages

Note about bibliography

Includes_bibliographical_references_(pages 98-103)

Rights

© 2023 Kartikeya Jayadurga Prasad Veeramraju, All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12303

Electronic OCLC #

1427258878

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