Evaluation and optimization of axial air gap propulsion motors for naval vessels. PDF
Preview Evaluation and optimization of axial air gap propulsion motors for naval vessels.
DL VAL ATESCHOOL M h CA Evaluation and Optimization of Axial Air Gap Propulsion Motors for Naval Vessels by Mark W. Thomas B.S., Electrical Engineering (1984) Oklahoma State University Submitted to the Departments of Ocean Engineering and Electrical Engineering in Partial Fulfillment ofthe Requirements for the Degrees of NAVAL ENGINEER and MASTER of SCIENCE in ELECTRICAL ENGINEERING and COMPUTER SCIENCE at the MASSACHUSETTS INSTITUTE OF TECHNOLOGY June 1996 © 1996 Mark W. Thomas. All rights reserved. The authorhereby grants to MITpermission to reproduce and to distribute publicly paperandelectronic copies ofthis thesis document in whole or in part. I, DL M0XLIBR.' ' VA<- 5TGRA ATE SCHOOL Evaluation and Optimization of Axial Air Gapj Propulsion Motors for Naval Vessels by Mark W. Thomas Submitted to the Departments of Ocean and Electrical Engineering on May 10, 1996 in partial fulfillment ofthe requirements for the degrees ofNaval Engineer and Master of Science in Electrical Engineering and Computer Science. ABSTRACT A unique method is used to optimize a design to multi-objective criteria. While the method is potentially applicable to any optimization where the cost function is not well defined, the products considered here are synchronous axial gap electric motors (both wound rotor and permanent magnet) and the application for which the motors are optimized is warship propulsion. All motors are rated at 40,000 hp, or approximately 25 megawatts. A preliminary design of an axial gap motor in this power range was completed as part of doctoral research by T. J. McCoy [1]. All wound rotor designs in this study are based on his work. However, the McCoy motor includes a rotating thermosyphon cooling system, A which is omitted here in favor ofa simple heatdensity calculation. permanent magnet machine design is presented and the resulting motors are optimized simultaneously with wound rotor types based on Naval propulsion criteria. This optimization method was originated by J. A. Moses et al. [2] and is termed the Novice Design Assistant. It involves the repetitive computer generation ofdesigns through random combinations ofdesign parameters. The results are compared to a database ofprevious designs. Any design found to be dominated in all desired attributes by another is discarded: otherwise it is added to the database. Dominance is determined by an evaluator module, tailored to the application, which compares motor attributes such as physical dimensions, weight and efficiency. The result ofmany iterations is an n- dimensional "frontier" of non-dominated designs, where n is the number of attributes considered. Since the number offeasible possibilities is large given that some design parameters may vary continuously, a low "hit" rate is avoided by mapping successful parameter combinations back to the design module using a Gaussian distribution. This mapping process is similar to that used by U. Sinha in applying the method to commercial induction motors [3], and preserves the creativity of the method while decreasing computer overhead time. Thesis supervisor: James L. Kirtiey Jr. Title: Professor of Electrical Engineering Biographical Note The author graduated from Oklahoma State University in May of 1984 with a Bachelor of Science degree in Electncal Engineering. He attended the Navy's Officer Candidate School in Newport. Rhode Island and was commissioned as an Ensign in the US Navy in October 1984. He served as a division officer aboard the destroyer USS David R. Ray (DD-971) for four years, qualifying as a Surface Warfare Officer and Gas Turbine Engineering Officer ofthe Watch. Further tours included instructor duty at Gas Turbine Engineering Officer ofthe Watch School in San Diego and two years as a main propulsion inspector at the Pacific Board ofInspection and Survey, afterjoining the Navy's Engineering Duty Officer community. He reported to MIT in June of 1993 for a three year tour of full time graduate work in the Naval Architecture and Marine Engineering (13A) program of the Ocean Engineering department.
The list of books you might like
