电磁飞机弹射系统的设计与仿真(英文版).pdf

Design and Simulation of an Electromagnetic Aircraft Launch System D Patterson, A Monti, C Brice, R Dougal, R Pettus, D Srinivas, K Dilipchandra （Department of Electrical Engineering University of South Carolina, Swearingen Center Columbia, SC 29208 USA ） E-mail - patterson@ieee.org Abstract —This paper describes the basic design, refinement and verification using finite element analysis (FEA), and operational simulation using the Virtual Test Bed (VTB), of a range of candidate linear machines for an electromagnetic aircraft launching system (EMALS) for the aircraft carrier of the future. Choices of basic machine format, and procedures for determining basic dimensions are presented. A detailed design is presented for a permanent magnet version, and wound field coil and induction machine versions are introduced. The long armature – short field geometry is discussed, and in particular the impact of this geometry on the scale of the power electronic drive system is presented. I. INTRODUCTION A. The Project Modern ship designs are increasingly moving towards the use of electricity to distribute, control, and deliver energy for the multiplicity of on board needs. This trend has already resulted in large direct drive electric machines for traction in commercial shipping. In some significant cases, including traction, adoption in military applications is rather slower, because of the comparatively low achievable power, energy and torque, per unit volume and per unit mass, of electro-mechanical energy conversion systems. However the benefits of controllability, robustness, reliability, damage management, operational availability, reduced manning etc. are undeniable. Whilst all actuation systems are under continuous investigation, there is a high level of interest in determining the feasibility of an electromagnetic aircraft launch system (EMALS) for aircraft carriers. Studies are being carried out at the University of South Carolina (USC) to evaluate alternative design concepts and to determine their feasibility and comparative strengths. Simulation uses the Virtual Test Bed (VTB), a new environment for simulation and virtual prototyping of power electronic systems that includes not only simulation of system dynamics, but also solid modeling of the system and visualization of the system dynamics [1]. EMALS also represents a challenging test case for VTB itself. Models of the different parts of the systems will be built up from the specifications and the characteristics given by U.S. Navy, and from engineering design principles. B. The Challenge The design of an EMALS has many intriguing challenges. The likely specifications and technical features include: ? Maximum velocity: - 200 kt, ~100 m/s ? Maximum power stroke: - 310 ft, ~100 m ? Min braking distance - moving member:- 30 ft, ~10m ? Maximum Energy: - 120 MJ ? Maximum Thrust: - 1.3 MN ? Minimum time between launchings:- 50 s. A typical launch might be for a 25000 kg aircraft accelerated to 150 kt in 2.7 s, at an acceleration of 2.8 g. This represents a total energy of 70 MJ. Acceleration to the maximum velocity requires a more-challenging 2 s stroke, at a constant acceleration of 5 g. Whilst the overall system design must include storage, power electronics, and control system design, this paper will concentrate on the electric machine design, and introduce some of the power electronics and control issues. II. LINEAR MACHINE DESIGN A. Background A substantial body of research exists studying large linear motors, however the majority of these are induction machines, and by far the largest number of these are what are known as short primary - long secondary machines. We will also use the terminology short armature - long field for this geometry, a little more apt for machines other than induction machines. Significant issues in design of these machines are the study of edge effects and end effects. A very common application of short primary long secondary machines is for traction in electric trains, where the energy is delivered to the train via a catenary or third rail system, and applied to an on board armature or primary. The secondary, or field member, is some form of complete track length reaction rail. The Westinghouse ―Electropult‖, developed during World War II is an aircraft launching linear induction machine of this form. This project is examining an extensive range of possible electrical machines, permanent magnet (PM) machines, machines with wound field (WF) coil structures, (which would in general need to be superconducting), and induction machines, (IM). The issue of the transfer of 120 MJ in 2 seconds to a moving member, (referred to hereinafter as the shuttle) either through sliding contacts or some form of moving harness, is daunting. The ―Electropult‖ referred to above used sliding contacts; however, the thrust required for this EMALS project is about 20 times greater than that delivered by the Electropult. An historical description of the Electr。