Masters Theses

Abstract

"High-voltage energy storage systems, which employ large series strings of battery cells or ultracapacitors, can be found in many applications including the utility industry, power backup, and electric and hybrid vehicles. These vehicles need a power plant that is reliable and maintains integrity during the lifetime of the car. Battery and ultra-capacitor capacity imbalances stemming from manufacturing and ensuing driving environment and operational usage affect voltage levels, which must adhere to strict limits to ensure the safety of the driver. While balancing the voltages of the batteries will prevent any problems stemming from capacity mismatch, there are many ways to instantiate the solution. This thesis reviews, analyses, and classifies various existing charge equalization techniques including capacitive, inductive, and transformer storage methods.

In this thesis, a double-tiered capacitive shuttling technique is presented and applied to an idealized three-battery system simulation in order to balance the voltages. Parameters in the system are varied and their effects on the system determined. Simulation shows a substantial improvement in charge transport using the new topology. Experimental results verifying simulation are presented.

Many of the existing charge balancing techniques utilizing inductors as the charge storage unit require the use of a voltage sensing system to set the control system switching accordingly. This thesis introduces a new flyback-based converter to transfer energy between storage units; by placing a diode in series with the input to the converter, the need for a voltage sensing network is removed. This comes at the expense of a slight drop in efficiency and a change in the operating characteristics near the equalized voltage state. Analytical study near the equalization point is presented and simulation results are used to verify expected operational characteristics"--Abstract, page iii.

Advisor(s)

Ferdowsi, Mehdi

Committee Member(s)

Wu, Cheng Hsiao
Carroll, Douglas R.

Department(s)

Electrical and Computer Engineering

Degree Name

M.S. in Electrical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Summer 2006

Pagination

ix, 63 pages

Note about bibliography

Includes bibliographical references (pages 61-62).

Rights

© 2006 Andrew Christian Baughman, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

CapacitorsDiodesSolar vehicles -- Power supplyStorage batteries -- Design and construction

Thesis Number

T 9041

Print OCLC #

85860373

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