Effects of Design Parameters on Performance of Brushless Electrically Excited Synchronous Reluctance Generator

Permanent magnet synchronous generators, doubly fed induction generators, and traditional electrically excited synchronous generators are widely used for wind power applications, especially large offshore installations. In order to eliminate brushes and slip rings for improved reliability and maintenance-free operation, as well as to avoid costly permanent magnets, a novel brushless electrically excited synchronous reluctance generator having many outstanding advantages has been proposed in this paper. The fundamental operating principles, finite element analysis design studies and performance optimization aspects have been thoroughly investigated by simulations and experimentally under different loading conditions. The effects of different pole combinations and rotor dimensions on the magnetic coupling capacity of this machine have been specifically addressed and fully verified by off-line testing of the 6/2 pole and 8/4 pole prototypes with magnetic barrier reluctance rotor and a new hybrid cage rotor offering superior performance

Flux-adjustable permanent magnet machines in traction applications

This paper overviews the recent advances in flux-adjustable permanent magnet (PM) machines for traction applications. The flux-adjustable PM machines benefit from the synergies of the high torque density and high efficiency in conventional PM machines as well as the controllable air-gap field in wound-field machines, which are attractive for the traction applications requiring enhanced capabilities of speed regulation and uncontrolled voltage mitigation. In general, three solutions have been presented, namely the hybrid excited (HE), the mechanically regulated (MR), and the variable flux memory (VFM) machines. Numerous innovations were proposed on these topics during the last two decades, while each machine topology has its own merits and demerits. The purpose of this paper is to review the development history and trend of the flux-adjustable PM machines, with particular reference to their topologies, working mechanism, and electromagnetic performance

NASA Tech Briefs, March 1997

Topics: Computer-Aided Design and Engineering; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery/Automation; Manufacturing/Fabrication; Mathematics and Information Sciences; Life Sciences; Books and Reports

NASA patent abstracts bibliography: A continuing bibliography. Section 1: Abstracts (supplement 06)

Patents and applications for patent introduced into the NASA scientific and technical information system are cited. Each entry consists of a citation, an abstract, and a key illustration selected from the patent or application for patent. The patent and application for patent citations are indexed according to subject, inventor, source, number, and accession number

NASA Patent Abstracts Bibliography: A Continuing Bibliography. Section 1: Abstracts (Supplement 48)

Abstracts are provided for 85 patents and patent applications entered into the NASA scientific and technical information system during the period July 1995 through December 1995. Each entry consists of a citation, an abstract, and in most cases, a key illustration selected from the patent or patent application

Aeronautical engineering: A continuing bibliography with indexes (supplement 321)

This bibliography lists 496 reports, articles, and other documents introduced into the NASA scientific and technical information system in Sep. 1995. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment, and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Dynamical systems : control and stability

Proceedings of the 13th Conference „Dynamical Systems - Theory and Applications" summarize 164 and the Springer Proceedings summarize 60 best papers of university teachers and students, researchers and engineers from whole the world. The papers were chosen by the International Scientific Committee from 315 papers submitted to the conference. The reader thus obtains an overview of the recent developments of dynamical systems and can study the most progressive tendencies in this field of science

No-load performance analysis of brushless DC machines with axially displaceable rotor

Brushless dc (BLDC) machines with a surface-mounted permanent magnet (SMPM) rotor meet the high-torque and high-efficiency requirements for automotive applications. However, their constant-power operation region is limited due to the low phase inductance. As an alternative to the electrical field-weakening methods, the speed range of radial-flux BLDC machines can be extended by mechanically reducing the axially overlapping length of the stator and the rotor. In this paper, the no-load performance of an SMPM-rotor BLDC machine with an axially displaceable permanent-magnet rotor is analyzed. The effectiveness of this mechanical field-weakening method is limited through the flux components due to the stator/rotor misalignment and the additional losses. The cause of the flux components due to the stator/rotor misalignment and the dependence of back-electromotive-force waveforms on the axial rotor position are investigated by using 3-D finite-element method (FEM) analysis, where the effects of the end-winding geometry and design are taken into account. Moreover, the additional loss mechanisms due to the stator/rotor misalignment are identified, and the no-load additional losses are determined by using the experimental and 3-D FEM analysis results. Finally, the numerical results are verified by using test-bench measurements