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This paper discusses the design, fabrication, and analysis of a coil assembly for a multistage induction-type coilgun system with the pulsed power module. The voltage, current, force, velocity, acceleration, and efficiency of the coilgun system were analyzed using the finite-element method. Based on the results of the electromagnetic analysis, the geometry of the coil assembly part for coilgun system was defined. The designed coilgun system has been found to exhibit high energy efficiency and safety against the force and temperature of the coil assembly. The designed coil assembly part was fabricated and analyzed. The design specifications and analysis results concerning the coilgun can, hence, be effectively utilized to develop a large-scale multistage induction-type coilgun system. [ABSTRACT FROM AUTHOR]

Electrical machines with transverse-flux (TF) paths have flexible structures, which may help to improve the performance of machines. Comparing to the flat-type structure in linear machines, the tubular-type structure is good for improving the electromagnetic thrust density. In this paper, a novel single-phase tubular-type switched reluctance linear launcher with TF path is proposed. Its stator is composed of several U-shaped modules, and windings are coiling on the yokes of these modules of the stator. This structure differs from the traditional tubular linear machine, and it avoids two windings squeezing in one stator slot so that the winding assembling process is easy. Gear-shaped poles on mover form more effective magnetic circuits than conventional machines. In the design process, the sensitivity analyses on five important parameters are conducted with the finite-element method (FEM) to achieve better performance on thrust density. The prototype has been manufactured and tested. The static and dynamic performances measured through experiments coincide well with the simulation results. These prove the correctness of the calculated FEM results and the well-manufactured machine, and its superiority in thrust density is verified. [ABSTRACT FROM AUTHOR]

In previous studies, the field winding of the brushless pulsed alternator (BPA) is embedded in the stator slots, which is supplied by dc power or variable frequency power. The advantage is that the field current can be independently adjusted. It means that the BPA system needs a standalone excitation system, which will increase the volume and cost of the system. If we substitute electric excitation for permanent magnet excitation, not only the volume and cost of the BPA system can be decreased but the efficiency and flexibility can be enhanced. In this paper, the design schemes for electric excitation and permanent magnet excitation BPA are presented. For comparison, the stator and rotor dimensions of the two kinds of BPA are both the same. The characteristics of electric excitation and permanent magnet excitation BPA are analyzed by the finite-element method and field-circuit coupling method. Finally, the BPA systems with a resistive load are established, the performances of both the two excitation modes are compared. According to the simulation results, we conclude their advantages and disadvantages. [ABSTRACT FROM AUTHOR]

Multisegmented dual-stator pulsed linear induction motor (LIM) is suitable for electromagnetic (EM) catapult based on the former research. This paper mainly analyzes the numerical model of same and reverse mode of the dual stator, magnetic thrust and EM parameters, and the magnetic field distribution has been built by finite-element model and the static performance are gotten by the prototype machine. Based on the analysis results and static experiments, the closed-loop control models for the dual stator have been established, and the dynamic launch test has been performed by using of multisegment prototype LIMs. The test results show that the dual-stator LIMs can accelerate the 300-kg load to the speed of 15 m/s within 11-m launch stroke. The fluctuation of the slip frequency is quite small and the block transition is smooth during the launching process. The test results show good agreement with the commanded values, which verify the dual-stator LIM model and control strategy. [ABSTRACT FROM AUTHOR]

A reciprocating single-phase tubular switched reluctance linear launcher (TSRLL) with a short stroke is presented in this paper. The parametric design of this launcher is achieved based on finite-element method (FEM). By using the finite-element (FE) software FLUX, the 2-D and 3-D electromagnetic analyses of this launcher are carried out, respectively. The characteristic curves of position-current-flux linkage are analyzed by the 2-D and 3-D FEM. The prototype tests are conducted to verify the FE analyses. The static tests results show that the 3-D FE calculated results are more precise than the 2-D FE calculated results, and they coincide well with prototype static test results. The effectiveness of the FE model for the TSRLL is further testified by the results of prototype dynamic tests. Finally, some analyses on sensitivity parameters are conducted to further improve the performance of the TSRLL. [ABSTRACT FROM PUBLISHER]

This paper presents a nontraditional power supply system for lasers in which an active compensated pulsed alternator (ACPA) drives the flashlamp load directly instead of the capacitor groups. However, the delivered power and pulsed width of the ACPA are two pivotal machine output parameters, which are determined by the flashlamp load. In other words, the characteristics of the flashlamp load must be elaborately considered during the design process of ACPA. In this paper, the structure of a new single-phase iron-core nonsalient pole ACPA is proposed, which couples the flashlamp load. The theory and advantages of ACPA are also introduced. The characteristics of the transient magnetic field distributions are calculated by finite-element analysis to verify the electromagnetic programming design of ACPA. A circuit model of the power supply system is then established to simulate the performance. Some simulation waveforms are obtained and explained. [ABSTRACT FROM PUBLISHER]

A thermal model of a switched reluctance linear launcher is presented in this paper. The accuracy of the thermal model is verified by comparing experimental data with those results derived from finite-element method simulation. The temperature distribution of a switched reluctance linear launcher is derived based on the stator copper losses as the main heat power with measured stator winding current by the current sensor. The maximum temperature rise curves under different ambient temperature and different heat power of winding A are studied. The heat dissipation power of four air convection surfaces under different ambient temperature and the different heat power of winding A is also studied. Furthermore, this paper achieves optimization in thickness of the stator plate and in adding fins to the stator plate for heat dissipation with the present model. It is shown that the stator plate is the maximum heat dissipation power surface so that it can be adopted as the main heat dissipation channel and the effect of heat dissipation is obvious by adding fins to the stator plate. [ABSTRACT FROM PUBLISHER]

This paper presents the investigation of a novel capacitor-charging power supply through inertial energy storage of a homopolar inductor alternator (HIA). The structure of a new 18/16-pole HIA is proposed, and we introduce the theory and advantages of HIA. The characteristics of the static magnetic field distributions are calculated by finite-element analysis, and a basic mathematic model of HIA is set up. We propose an efficient and stable capacitor-charging circuit topology to meet the requirements of this system. A functional model of the key device, namely, IGCT, is also established. Finally, we verify its feasibility and advantages through analysis of the system simulation. [ABSTRACT FROM AUTHOR]

This paper presents an approach for enhancing the thrust force of a tubular transverse flux permanent magnet linear machine (TFPMLM) that has been developed for electromagnetic applications. It is shown that, by introducing auxiliary cores to suppress the leakage flux, the thrust force of the tubular TFPMLM can be significantly enhanced, by \sim130\%, under the same volumetric constraints. The effectiveness of the proposed technique is validated by extensive three-dimensional finite element computations. [ABSTRACT FROM PUBLISHER]

This paper investigates the thrust characteristics of the transverse flux tubular linear machine, including theoretical analysis and numerical calculation. The influence of structure parameters on the thrust force and cogging force characteristics is analyzed in detail. Special attention is paid to the length of stator segment, air-gap length, and pole-arc coefficient. The analysis results provide a foundation for the optimum design of electromagnetic launcher. [ABSTRACT FROM AUTHOR]

Some intriguing advantages of permanent-magnet linear synchronous machines (PMLSMs), such as simple structure, high thrust, high efficiency, ease of maintenance, and controller feedback, make it possible to take the place of steam catapults in the future. The conventional PMLSM is renowned for its simple structure and high efficiency, whereby the high reactive power resulted from great leakage inductances during the long stator. Thus, great concern is paid to the section structure of the PMLSM. A sectioned permanent-magnet linear synchronous machine (SPMLSM) used in the EMALS is introduced in this paper, whose stator core is continuous but the armature winding is divided into two sectioned parts. First, the electromagnetic fields of the SPMLSM are investigated analytically. Then, the fields are computed by the finite-element method (FEM) and measured experimentally. Not only are the self-inductances and mutual inductances in one section studied but also the mutual inductances between the two sections. These inductances are then calculated by the FEM and measured experimentally. Good correlation among the results was obtained by these three methods. [ABSTRACT FROM AUTHOR]

As a kind of high power pulse power supply, the air-core compensated pulse alternator (CPA) is widely used in electromagnetic emission, laser weapon, pulse capacitor charging, and other fields. A brush structure or a brushless structure can be used in the air-core CPA. Because the brushless structure is more suitable for high-speed operation and has higher reliability, more and more scholars have studied the brushless structure air-core CPA. In this article, an electric excitation brushless air-core CPA which the equivalent pole-pairs number is one is proposed. The CPA adopts a brushless rotor winding designed based on the principle of magnetic field differential modulation, which can simultaneously produce two and three pole-pair magnetic fields rotating in the same direction. The rotor winding can couple the field winding and the armature winding at the same time, thus realize electromechanical energy conversion. Under the same conditions, the pulsewidth of pulse discharge current can be significantly increased by reducing the number of pole pairs of the CPA and the output energy of a single pulse can be improved. In this article, a detailed design method of the differential modulation rotor winding of the CPA is presented, and the harmonic content of the CPA is calculated by analytical and numerical methods. Finally, the finite element model is used to analyze the related performance of the CPA, and the analysis results verify the effectiveness of the design scheme. [ABSTRACT FROM AUTHOR]