Author

Yijin Wei

Publication Date

2016-5

Document Type

Honors Thesis

Department

Engineering

Keywords

Proton exchange membrane fuel cells, Electric current converters, Hybrid power systems, Fuel cells, DC/DC converter, Hybrid, Power system, Optimization, Experimental

Abstract

Proton exchange membrane fuel cells (PEMFC) employ electrochemical reactions to produce power from hydrogen and oxygen with water as the only by-product. PEMFCs are clean, efficient and quiet power sources that can operate at relatively low temperature. Because PEMFCs are able to provide continuous electric power, they have been widely explored for transportation and portable applications. Miniature PEMFCs are considered an alternative to rechargeable batteries, such as lithium-ion batteries, in mobile devices. The application of interest to this work is to power the altitude control, data acquisition, data storage and communication on controlled meteorological (CMET) balloons used for tracing gas species and collecting meteorological data. Specifically, we are exploring the electrical configuration that combines a PEMFC stack with a direct-current-to-direct-current (DC/DC) converter in order to decrease the system mass. Such reduction in the overall system mass is critical in order to compete with existing battery technologies. In this project, we designed, prototyped and tested three micro power DC/DC converters that can be deployed in series with PEMFC power sources. Each prototype DC/DC converter was experimentally verified in direct connection to a miniature two-cell PEMFC stack. The experimental data provided proof-of-concept for the use of miniature PEMFC stack with DC/DC converters for reduced power system mass. Moreover, this thesis develops a method that optimizes the design of fuel cell stack combined with DC/DC converters to minimize the system mass while meeting the electric power needs. A general procedure applicable to any power system is summarized for sizing the fuel cell stack connected with DC/DC converters. This method is applied to the CMET balloon power system as a case study.

Language

English

Comments

ix, 70 pages : illustrations (some color). Honors project, Smith College, 2016. Includes bibliographical references (pages 69-70)

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