Superconducting and conventional electromagnetic launch system for civil aircraft assisted take-off

This paper summarizes the results of a design study investigating the use of linear electric motors in an aerospace electromagnetic launcher application requiring 7g’s of horizontal acceleration to a velocity of 300m/s. The study initially reviews the current state of high-speed electric machines in applications similar to the one proposed. Induction and synchronous linear motors are then evaluated for suitability to the application by analyzing their characteristics in this high-speed operating regime. A detailed design approach is used to synthesize machines capable of meeting the launcher’s performance requirements, since the conditions fall outside of the conventional design envelope. Realistic physical features of all electrical power system components are included to ensure the evaluated systems are physically realizable. The two motor types are compared for suitability to the application based on performance, cost, and system integration issues. Finally, a prototype demonstrator design is proposed to verify the results of the study.

Linear motor eliminates the middle part of mechanical drive train, but because of structural characteristics of itself, must to take effective measures to reduce thrust fluctuations, or direct drive will lost its original meaning. In this paper, firstly research on detent force of moving magnet type permanent magnet synchronous linear servo motor and analyze the principle of generate detent force, secondly analyze the cogging force of moving magnet type permanent magnet synchronous linear motor and obtain the expression of cogging force maximum value, finally propose effective method to reduce detent force.

The engine size of modern passenger transport aircraft is principally determined by take-off conditions, since initial acceleration requires maximum engine power. An electromagnetic launch (EML) system could provide some or all of the energy required at takeoff so that the aircraft engine power requirement and fuel consumption may be significantly reduced. So far, EML for aircraft has been adopted only for military applications to replace steam catapults on the deck of aircraft carriers. This paper will describe the potential application of EML to propel civil aircraft on the runways of modern airports. A comparison of synchronous and asynchronous electrical motor systems designed to launch an A320-200 sized aircraft is presented. The paper also describes a solution of the transient heat transfer problem applied to the conductive components of EML systems.

The severe drawback of slotted permanent magnet linear synchronous motor (PMLSM) is the detent force, particularly when accurate positioning and constant low speed is required for numerically controlled machine tool. In this paper, a novel short-armature slotted type multi-segment permanent magnet linear synchronous motor (MSPMLSM) is proposed and constructed to reduce the detent force. It consists of a proper shift of the multiple segments of iron core relative to the PMs. The detent forces of MSPMLSMs with different number of segment are analyzed and simulated by finite element method (FEM). The proposed structure has been proved to be a very effective approach for the reduction of detent force. Then this paper presents the statistical and mathematical optimum design of a 3-segment PMLSM using response surface methodology (RSM) together with FEM to minimize the detent force. Full factorial design and steepest ascent method, one of the iterative search method, is proposed to establish optimal design area for applying RSM. Finally, the global optimal design is predicted and the optimally designed one is manufactured, and the numerical results and measured results are reported to validate the effectiveness of this proposed method.

No-lapping concentrated windings permanent magnet linear synchronous motor (PMLSM) which possesses notable advantages such as big thrust force density, short winding head and small magnetic resistance is the preferred drive motor on Linear motor cordless upgrade system. In the paper 15 slots 16 poles PMLSM has been taken as example. On the basis of d-q dual-response theory, key parameters such as the motor resistance of q-axis (quadrature) and d-axis (direct) have been calculated by Finite Element Method. Thus mathematic model of PMLSM steady-state analysis has been built. PMLSM performances such as current, thrust force, power factor, efficiency, and electric power brake force affecting by supply voltage and ambient temperature change have been studied respectively both on load condition and no-load condition. The experiment results agree with theoretical analysis, with good prospects of permanent magnet (PM) linear synchronous motor for design and application of ropeless elevator.

A new transfer model vehicle system for automatic horizontal transport, especially in short-turning-area applications, has been developed in the authors' laboratory. It is driven by permanent magnet (PM) linear synchronous motors (LSMs), and can operate efficiently in orthogonally-crossed-guideway network in mass-reduced mode. This paper presents a fundamental study of the PM LSM vehicle running on such network guideways with two crossings. The experimental results have shown a good agreement of the vehicle motion with the demand pattern in network running operation.

Compared with steam catapult system, electromagnetic launcher (EML) system is highly integrated, and it has high and well matching performance. It will be widely used aircraft carriers ejection, rocket launchers etc in future. Double-side tabular permanent magnet linear synchronous motor (PMLSM) for electromagnetic launcher can meet the requirements of big thrust and high efficiency etc. It can accelerate the launcher at the expected speed in short time. The thrust characteristic of the launcher is essential to the whole electromagnetic launcher system. Large thrust and small thrust ripple are both expected. This paper studies thrust characteristic of different pole arc coefficients, compares the series and parallel magnetic circuit structures, and analyses the method of staggering a certain distance between poles on both sides. In order to achieve the goal of large thrust, the Launcher is often designed with high current density. As a result, it is of great loss and has quick temperature rise. This paper establishes numerical model of the two-dimensional (2D) primary transient temperature field. The temperature field of the short-term system is analyzed. The calculated and experimental results of the electromagnetic launchers can provide a basis for optimum design.

In this paper a state feedback controller for tubular linear permanent magnet synchronous motor (TLPMSM) containing two gas springs, is presented. The proposed TLPMSM controller is used to control reciprocating motions of TLPMSM. The analytical plant model of TLPMSM is a multi-input multi-output (MIMO) system which is decoupled to some sub single-input single-output (SISO) systems, then, the sub SISO systems are converted to sub-state space models. Indeed, the TLPMSM state space model is decoupled to some sub-state spaces, and then, the gains of state feedback are calculated by linear quadratic regulation (LQR) method for each sub-state space separately. The controller decreases the distortions of the waveforms. The simulation results indicate the validity of the controller.

In this paper, a technique for reducing the cogging force in slotted permanent magnet linear synchronous motors (PMLSMs) is presented. A two-step minimization process that depends on the slotting and end effects is proposed. Taguchi's parameter method, coupled with 2-D and 3-D finite element analysis (FEA), is employed to minimize the cogging force.

A synchronous reluctance motor has many advantages because it has no permanent magnet, such as low back emf in high‐speed operation, maintaining performance in a high‐temperature environment, and so on. Therefore, many rotor constructions have been studied and developed. The rotor with multiflux barrier structure has the merit of easy construction and high performance.The linear synchronous reluctance motor has been developed. It is necessary to improve the performance of the mover design for industrial use, because of its low power factor.In this paper, we propose a novel configuration of mover for the linear synchronous reluctance motor, and examine the static characteristics of the motor with reluctance equalization design by means of the finite element method. From analytical results, it is demonstrated that the static characteristics of the linear synchronous reluctance motor are greatly improved by the reluctance equalization design at the iron layer in the mover. © 2002 Scripta Technica, Electr Eng Jpn, 138(4): 61–69, 2002; DOI 10.1002/eej.1139

This paper deals with the thrust characteristic and design parameters, such as teeth width and height, of a linear synchronous reluctance motor (LSynRM) using finite element analysis (FEA). And then, we select the optimum design parameter in terms of the thrust characteristic from the results. We used this optimum design parameter in manufacturing an LSynRM. Finally, the design of LSynRM is extensively verified by measurements and FEA.

For linear motor system, which is an electromechanical multi-parameter, strong coupling, multi-variable, strong non-linear system, the fact that the system control is difficult to carry out is becoming increasingly prominent. This paper proposes an analysis of relative weights of various factors for thrust fluctuations in permanent magnet synchronous linear motor (PMSLM) based on the Fuzzy Analytic Hierarchy Process, (FAHP). First, the paper analyzes the complexity of PMSLM and thrust fluctuations causes the relevance and variability, pointing out how to reduce the linear motor thrust fluctuation analysis of the existing problems. Then, the paper introduces the theory of fuzzy analytic hierarchy theory and its application characteristics and steps. Finally, the application of fuzzy analytic hierarchy process is proposed to analyze linear motor thrust fluctuation factor weights. The results show the end effect of the thrust fluctuations, the ripple disturbance, magnet distribution and cogging effects. This result can be used as a key intervention to reduce the thrust fluctuation fluctuations for PMSLM.

During the last years the applications for material processing and transportation based on linear motors increased in many industrial fields. A highly modular topology of a linear servo-drive system based on permanent magnet synchronous linear motors is presented here. The proposed system topology differentiates itself from other linear drive topologies through its scalability, so that the system can expand as much as the application requires it. The means by which the whole system can be controlled and monitored, as well as experimental results are presented.

The replacement of steam catapults with electromagnetic ones is becoming an overwhelming trend in aircraft launch systems. The Electromagnetic Aircraft Launch System (EMALS) offers significant benefits to the aircraft, ship, personnel, and operational capabilities. EMALS has such advantages as high thrust, good controllability, reusable, etc., as a launching motor, a double-side plate Permanent Magnet Linear Synchronous Motor (PMLSM) can provide high instantaneous thrust. This paper compared two PM mover with quasi-Halbach array topology and radial topology for PMLSM application. A detailed analytical modeling based on Maxwell equations is presented for analysis and design of PMLSM with Halbach array. Finally, employing 2-D nonlinear time-stepping transient finite element method to demonstrate validity of the analytical analysis and parametric search. Using FEA, the effects of the parameters on the thrust amplitude are analyzed. Finally, A design optimization method applied to PMLSM with Halbach array, that the obtained result form 2-D FEM shown the increase of thrust force and flux density distribution in the air gap.

In order to make the speed adjustment system of the permanent magnet synchronous linear motor more stable and make the convergence performance of the speed control system better, a speed regulator based on the terminal sliding mode algorithm is proposed. In addition, the permanent magnet synchronous linear motor will also be affected by temperature changes during its operation. Aiming to enhance the adaptability of linear motors to parameter changes, a terminal sliding mode speed control idea based on adaptive parameter identification is proposed. The Popov stability theory and the mathematical model of linear motor are used to construct a parameter identification system. The identification flux parameters are used as the control algorithm of the terminal sliding mode speed regulator and the update matching of speed regulator flux parameters and motor system parameters are realized. Through the above algorithm, the performance of the entire speed control system is improved. The results of simulation experiments can illustrate the effectiveness of this control method and its effect on improving the control performance.