EMALS optimal design

A semi-analytical model of the Double Sided Tubular Linear Induction Motor (DSTLIM) is adopted for the optimization of the thrust force of the stages of an ElectroMagnetic Aircraft Launch System (EMALS). The model allows a fast and accurate prediction of all the electromagnetic quantities in the device, including the thrust force, the back-electromotive force, the distribution of the induced current and the average magnetic flux density in the teeth. This provides a basis for the design which has been performed by a novel evolutionary optimization algorithm. By using the semi-analytical formulation, the characterization of the machine is greatly facilitated so allowing a fast evaluation of the cost function and of the design constraints

History and recent advancements of electric propulsion and integrated electrical power systems for commercial & naval vessels

Due to developments in power electronics, electric machines, energy storage and control, electric propulsion and integrated electrical power systems have become major trends for commercial and naval vessels. This is mainly due to the fact that the use of electric propulsion and integrated power systems can improve efficiency and fuel consumption while reducing noise and vibration when compared to conventional systems. Such advantages are extremely attractive to vessel owners due to increasingly stringent emission requirements, especially in environmental control areas, from the international maritime organization. This paper aims to summarize the recent advancement of marine power systems including propulsion systems, electrical distribution systems and novel loads

An improved equivalent circuit model of a single-sided linear induction motor

The derivation of the equivalent circuit for a single-sided linear induction motor (SLIM) is not straightforward, particularly if it includes longitudinal end effects from the cut-open primary magnetic path, transversal edge effects from the differing widths between the primary lamination and secondary sheet, and half-filled primary slots. This paper proposes an improved series equivalent circuit for this machine. The longitudinal end effects are estimated using three different impedances representing the normal, forward, and backward flux density waves in the air gap, whose two boundary conditions are deduced by introducing the conception of magnetic barrier surface. The transversal edge effects are accounted for by correction coefficient K t̄ and air-gap flux density correction coefficient K b̄. Using the series circuit, the performance of the SLIM was assessed in a similar manner to a rotating induction machine. A 4-kW SLIM prototype was tested, which validated the simulation technique. © 2010 IEEE

Steady and dynamic performance analyses of a linear induction machine

This paper based on the winding function algorithm presents an improved equivalent circuit to analyze single linear induction motors (SLIMs) applied in the linear metro. The circuit deduced from the air-gap magnetic flux density equations can analyze steady and transient performances considering end effects, half filled slots, saturated iron and skin effect. Firstly several stable cases like constant thrust/power region, constant current constant frequency or variable frequencies, constant voltage constant frequency or variable frequencies are presented in detail. Then, maximal thrust at a given speed is optimized by modifying the optimal slip frequency. Finally, transient characteristics of SLIM under constant current constant frequency are investigated. The results indicate that winding function method is one effective way to study SLIM, especially its end effects. It can be used in the electromagnetic design and performance investigation for SLIM combining relative control schemes

NASA Tech Briefs Index, 1977, volume 2, numbers 1-4

Announcements of new technology derived from the research and development activities of NASA are presented. Abstracts, and indexes for subject, personal author, originating center, and Tech Brief number are presented for 1977

Fiscal year 1973 scientific and technical reports, articles, papers, and presentations

Formal NASA technical reports, papers published in technical journals, and presentations by MSFC personnel in FY73 are presented. Papers of MSFC contractors are also included

Small business innovation research. Abstracts of completed 1987 phase 1 projects

Non-proprietary summaries of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA in the 1987 program year are given. Work in the areas of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robotics, computer sciences, information systems, spacecraft systems, spacecraft power supplies, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered

Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

Satellite Control System: Part I - Architecture and Main Components

This chapter provides introductory material to satellite control system (SCS). It is based on the author’s experience, who has been working in areas of SCS development, including designing, testing, operating of real SCS, as well as reviewing and overseeing various SCS projects. It briefly presents SCS generic futures and functional principles: tasks, architecture, basic components and algorithms, operational modes, simulation and testing. The chapter is divided into two parts, namely, Part I: SCS Architecture and Main Components and Part II: SCS Simulation, Control Modes, Power, Interface and Testing. This chapter focuses on Part I. Part II will be presented as a separate chapter in this book

The 15th Aerospace Mechanisms Symposium

Technological areas covered include: aerospace propulsion; aerodynamic devices; crew safety; space vehicle control; spacecraft deployment, positioning, and pointing; deployable antennas/reflectors; and large space structures. Devices for payload deployment, payload retention, and crew extravehicular activities on the space shuttle orbiter are also described