CIVINS / CIVINS

Approved for public release; distribution is unlimited / An evaluation was conducted of the various propulsion motors being considered for electric ship propulsion. The benefit of such an evaluation is that all of the propulsion options being considered by the U.S. Navy have been described in one document. The AC induction motor, AC synchronous motor, High Temperature Superconducting (HTS) motor and Superconducting DC Homopolar Motor (SDCHM) are examined. The properties, advantages, and disadvantages of each motor are discussed and compared. The power converters used to control large propulsion motors are also discussed. The Navy’s IPS program is discussed and the results of concept testing are presented. Podded propulsion is introduced and the benefits are discussed. The final chapter presents the simulation results of a volts/Hertz controlled 30 MW induction motor. The evaluation revealed that the permanent magnet motor is the best propulsion motor when considering mature technology, power density, and acoustic performance. HTS motors offer significant volume reductions and improved acoustic performance as compared to conventional motors. This includes both AC and DC HTS motors. The main obstacle for the SDCHM remains the unavailability of high current capacity brushes. / Ensign, United States Navy

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This research is a preliminary design and feasibility analysis of a new type of shipboard electrical distribution system for Naval vessels. The design combines three traditionally separate disciplines: damage control, marine engineering, and electric power engineering to produce a hybrid system well suited for present and future surface warship environments. The design structure is a combination of shore-based power utility and shipboard distribution. The primary section is an interconnected bus feeder ring which resembles a shipboard vertical loop firemain. The bus feeder ring emulates the firemain’s network structure because it is well suited for both normal and emergency operating conditions. The distribution ring is used to transfer power between fire zones to load centers which radially feed loads within each zone. The electrical feasibility of the system was established through standard power system load flow contingency analysis, use of Navy design specifications, and direct comparison with an icebreaker radial electrical system. The new system could best be applied to small ships where the effective use of zone distribution is difficult, or where automation is needed to implement reduced manning. For large ships, this system would provide additional design alternatives which could help to reduce intersystem design interference where the requirements for one system impinge on those of another. As a final point, this system provides a viable network for facilitating the application of shore-based automatic switching technology to Naval vessels. / Master of Science

As the United States Navy moves toward the all-electric ship, the need for a robust, high fidelity inverter for propulsion motors becomes mandatory. Military vessels require high power converters capable of producing nearly sinusoidal outputs to prevent torque pulsations and electrical noise that can compromise the mission location. This thesis presents a hybrid pulse-width-modulated controller for a 3x3 Cascaded Multi-Level Converter (CMLC). Ancillary results include a simple technique for extracting the reference sine wave from an independent bulk converter and implementing a synchronization technique that coordinates a space vector modulation controller with the switching pattern of a bulk inverter. The algorithms were tested on CMLC hardware that resides in the Naval Postgraduate School Power Systems Laboratory, and the results were compared with a sine-triangle pulse width modulation algorithm. The controller and converter were used to power a quarter-horsepower three-phase induction motor.

Cheung, Wai Ming Edwin. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 107-112). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstracts also in Chinese.

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Typescript (photocopy). / Digitized by Kansas Correctional Industries

Thesis (Nav. E.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004. / Includes bibliographical references (p. 89-90). / The Non-Intrusive Load Monitor (NILM) provides a method of measuring component performance and source power quality through a single point of entry in the power distribution system. A study was performed utilizing the NILM onboard three different ships (along with experimentation in the laboratory) to determine its effectiveness in determining the state of mechanical systems through analysis of electrical power data. Data collected from the Auxiliary Seawater System onboard the USCGC SENECA indicate that the NILM is able to predict several faults (clogged pump inlet strainers, faulty motor/pump coupling, fouled heat exchangers) as well as provide a backup indication of flow levels to heat loads. Data collected from the Sewage System of the SENECA indicate several metrics which can be applied to cycling systems in general to differentiate between periods of heavy usage and fault conditions. Finally, data collected from the Steering System of the SENECA as well as a yard patrol boat operated by the Office of Naval Research shows the potential of the NILM to be used as a control system without the need for separate mechanical transducers. / by Jack S. Ramsey, Jr. / S.M. / Nav.E.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCH. / Includes bibliographical references. / As the electric utilities face ever increasing peak power production requirements, (mostly from the commercial sector) scheduled "time-of-day" pricing schemes have become imperative. At present, most conservation strategies for commercial buildings focus on the reduction of energy consumption orchestrated (justifiably) by t he expense of electrical energy for lighting and cooling which dominate their loads. However, these conservation schemes, such as higher efficiency lamps, various glazing techniques, etc., do not alter the time of consumption nor do they utilize the lower off-peak electrical rates. The results are as before; high energy costs due to peak (daytime) consumption, and projected savings from the various conservation strategies are overshadowed or not realized. This thesis investigates a decentralized off-peak cooling system for commercial office buildings utilizing the structural mass as the thermal storage medium. The system incorporates an exposed concrete ceiling slab cooled at night with imbedded chilled water pipes and taking full advantage of off-peak electrical rates. The ceiling/slab - waterpipe system is modeled via two-dimensional finite difference methods for transient analysis. The sensitivity of the system to pipe size and spacing, internal loads, water temperatures, and surface geometry is assessed. The analytical results suggest the potential for application, however, additional research must be undertaken to investigate the economic implications of fabrication and to more adequately determine the effects of non-planar surface geometry. / by Rory Christopher Mathis. / M.S.