Theses and Dissertations at Montana State University (MSU)

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    Hardware and software development for implementation of fast and safe charging of commercial lihtium-ion batteries
    (Montana State University - Bozeman, College of Engineering, 2023) Hedding, Noah Robert; Chairperson, Graduate Committee: Hongwei Gao
    From single cells in handheld electronics to enormous packs in battery electric vehicles (BEV), batteries govern modern life. Lithium ion batteries (LIB) present the best available commercially available products for these applications; they have the highest energy densities and can output currents many times their capacity. But safely charging LIBs requires a slow and detailed process which is typically unacceptable for use in BEV and other rugged handheld devices; therefore, decreasing the required charging time would be greatly beneficial. Fast charging methods do present dangers and concerns. Unmonitored fast charging of LIBs allows for the potential of lithium plating where the lithium ions within the cell are converted to metallic lithium at the battery anode. Lithium plating can remove these ions from the charging and discharging process causing reductions in battery capacity. The metallic lithium structures formed also present the dangers of short circuit and thermal runaway. In this thesis, a charging protocol is developed using equivalent circuit models and experimentation with the goal of the elimination of lithium plating. First, equivalent models of a test cell were determined and validated. Then, this test cell was used to find the fast charging protocol both experimentally and through the use the equivalent circuit elements. Custom power electronics and software were then developed to implement the proposed charging protocol on commercial LIBs for 350 cycles. The results of this experiment show that the charging protocol did not create noticeable lithium plating while decreasing the charging time required by a typical constant current - constant voltage (CC/CV) from 50 minutes to 29 minutes. The proposed charging protocol decreased the charging time without stressing the LIB beyond its set limitation.
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    Real-time software-defined free-space optical communication system
    (Montana State University - Bozeman, College of Engineering, 2019) Sultana, Nishat; Chairperson, Graduate Committee: Ioannis Roudas
    Next-generation software-defined free-space optical (FSO) communication systems may substitute many conventional radio communication systems. The conventional single-purpose dedicated hardware resources in the telecommunication systems have significant limitations since they provide a single communication service using a specific standard at a time. It is also expensive to upgrade to the emerging new standards such as 5G New Radio (5GNR) by substituting the existing hardware resources. Reprogrammable FPGA-based Software Defined Radio (SDR) technology is deployed as a feasible solution to this problem since they can be reconfigured simultaneously realizing the user requirements. When integrated with the FSO system it opens a plethora of opportunities since the Visible Light Frequency Spectrum is barely occupied by the existing technologies and can be designed cost-effectively for the vast bandwidth it has to offer. In this thesis work, we implemented a real-time FSO communication system using an SDR platform. A fully-functional optical communication link has been accomplished using the Universal Software Radio Peripheral (USRP), MATLAB-Simulink communication toolbox and hardware support package, Laser diode, and a Photodetector. We demonstrate successful transmission and reception of baseband signals with very low bit error rate. Visually identical transmitted and received signals also validate the accuracy of the simulation results when compared to those obtained from the real-time FSO-SDR communication system.
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    Implementation of a radiation-tolerant computer based on a LEON3 architecture
    (Montana State University - Bozeman, College of Engineering, 2015) Turner, David Lee Douglas; Chairperson, Graduate Committee: Brock LaMeres
    It is desired to create an inexpensive, open-source, radiation-tolerant computer for space applications using commercial, off-the-shelf parts and a proven space-grade processor. Building upon previous work to develop the triplicate architecture using MicroBlaze soft-processors, this implementation, using a modification of the popular open-source space-grade LEON3 soft processor from Cobham Gaisler, enables more compatibility with NASA and existing space computing resources. A partially reconfigurable, triple modular redundant LEON3 processor was successfully implemented in a four-core design on an Artix-7 Field Programmable Gate Array to demonstrate an inexpensive and open-source method of developing radiation-hardened-by-architecture computer systems.
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