Switched Reluctance Linear Launcher Research Articles

A Novel Tubular Switched Reluctance Linear Launcher With a Module Stator

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.

A Transverse Flux Single-Phase Tubular-Switched Reluctance Linear Launcher With Eight-Pole Structure

Tubular-switched reluctance linear launcher (TSRLL) with novel structure is proposed in this paper. The structure of switched reluctance motor is simplified, and the unbalanced force of common types of switched reluctance linear launcher is alleviated in TSRLL. The structure of the single-phase TSRLL with transverse flux is introduced thoroughly. The 3-D finite-element (FE) model of the proposed TSRLL is constructed, and electromagnetic analysis is performed by the FE method (FEM). To improve the electromagnetic force of the proposed launcher, the sensitivity analysis is conducted by means of 3-D FEM. The stator yoke thickness, mover cylinder’s thickness, stator pole arc, and pole width ratio of TSRLL are optimized, and the results of the sensitivity analyses are presented. TSRLL with two different polarity distribution patterns is compared via static FE analysis. The dynamic simulation of TSRLL with optimal specification and polarity distribution is carried out and demonstrated, of which the results agree well with the static analysis by FEM.

Multiobjective Optimization Design of Single-Phase Tubular Switched Reluctance Linear Launcher

In this paper, a structure of single-phase tubular switched reluctance linear launcher (TSRLL) is presented, the initial dimensions are given. Moreover, sensitivity analyses of the key structural parameters are performed by the finite-element (FE) method. In order to improve the performance of TSRLL and solve the multiattribute decision-making problem well, a combined weighting method based on the fuzzy optimization iteration is proposed. Based on this algorithm, average electromagnetic thrust, electromagnetic force smoothing coefficient, and electromagnetic force copper loss ratio are chosen as optimization objectives. The calculated results show that the proposed algorithm is very suitable for multiobjective optimization of TSRLL. Also, the final scheme can meet the initial design requirements. The dynamic experimental results are consistent with the prototype test results.

Flux Characteristics Analysis of a Single-Phase Tubular Switched Reluctance Linear Launcher

This paper analyzed the flux characteristics of a single-phase tubular switched reluctance linear motor (TSRLM) based on magnetic equivalent circuit (MEC) method. The single-phase TSRLM is divided into five different parts, which are the teeth of the stator, the yoke of the stator, air gap, the teeth of the mover, and the yoke of the mover. The reluctance of every part is expressed in analytical formulas at five special mover positions. The flux linkages at five special mover positions are calculated by magnet tube method and Gauss–Seidel iteration method which takes the saturation into consideration. A high-order Fourier series method is used to map the nonlinear relationship between flux linkage, current, and mover position with the flux linkage data calculated by the MEC method. The calculated flux linkage is consistent with 3-D finite-element method and experimental results. The dynamic and static performance of the simulation utilized with MEC method is consistent with those in experiments, which verifies the accuracy of the MEC method proposed in this paper.

Flux Characteristics Analysis of a Single-Phase Tubular Switched Reluctance Linear Launcher Based on 3-D Magnetic Equivalent Circuit

This paper calculates the flux characteristic of a single-phase tubular switched reluctance linear launcher (TSRLL) with 3-D magnetic equivalent circuit (MEC) method. First, the 3-D finite element (FE) model of the single-phase TSRLL is established in FLUX, which is the foundation of the 3-D MEC model. The single-phase TSRLL is divided into different parts, including the teeth of the stator, the yoke of the stator, air gap, the teeth of the mover, and the yoke of the mover. The flux linkage at different mover positions and different currents is calculated with the proposed 3-D MEC model. Compared with the 3-D finite-element analysis (FEA) results, 3-D MEC model can obtain the flux characteristics of the single-phase TSRLL in a shorter time. The result of the 3-D MEC of the single-phase TSRLL is consistent with the 3-D FEM results and the experimental results, which validates the correctness of the proposed 3-D MEC model.

3-D Electromagnetic Analysis of Single-Phase Tubular Switched Reluctance Linear Launcher

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.

Multiobjective Optimal Design of Switched Reluctance Linear Launcher

In this paper, based on the comparisons of the stator pole flux density and phase current with corresponding rotary switched reluctance machine, the original design scheme of a 1-kW single-side switched reluctance linear launcher (SRLL) is obtained by a traditional method. To get higher efficiency and smaller force ripple, the genetic algorithm, which is improved to enhance the convergence rate and global accuracy, is applied to optimize the original design scheme. The global optimum values of key dimensions and control parameters are obtained, and the detailed structure of whole SRLL is given as well. Then a detailed equivalent lumped-parameter thermal network (LPTN) model of the considered SRLL is built, and temperature rises of some parts are obtained. To test the feasibility of the LPTN model, a 2-D finite element thermal model of the SRLL is built, and the temperature rises are obtained. The results from LPTN model match those from the finite-element method very well. Finally, the preliminary tests of the prototype of designed SRLL are carried out and the experimental results are presented.

Acceleration Closed-Loop Control on a Switched Reluctance Linear Launcher

In this paper we describe a developed switched reluctance linear launcher system with diagrams and photographs, which consists of a three-phase 6/4 structure simple side-switched reluctance linear motor, a three-phase asymmetric bridge power converter, and a TMS320F28335 DSP digital controller. The acceleration closed-loop control of the mover is proposed and verified for the first time. The acceleration closed-loop control of the mover is implemented by a fuzzy control algorithm. The turn-on angle and the turn-off angle of the main switches in the power converter are fixed, and the triggering signals of the main switches are modulated by the pulse width modulation (PWM) signal. The deviation of the acceleration between the given acceleration and the feedback practical acceleration, and the variation from the deviation of the acceleration are the two input control parameters. The increment of the duty ratio of the PWM signal is the output control parameter. The duty ratio of the PWM signal is regulated based on the fuzzy control algorithm. Flow diagrams of the software, such as the main program, the encoder unit time interrupt subroutine, analog-to-digital converter interrupt subroutine, and the fuzzy control algorithm subroutine are given. The developed prototype is tested experimentally. It is shown that the velocity response of the mover is satisfactory.

Modeling of Switched Reluctance Linear Launcher

A nonlinear simulation model of switched reluctance linear launcher drive based on MATLAB platform is presented in this paper. It consists of a three-phase 6/4 structure simple side switched reluctance linear motor, a three-phase asymmetric bridge power converter, and a closed-loop velocity controller, which is integrated with the magnetization curves of the switched reluctance linear motor obtained by the two-dimension finite-element electromagnetic field calculation, the nonlinear electrical network model of the power converter, and the excitation/commutation/velocity control algorithms. Those include mover relative position calculation module, controller module, power converter module, phase winding modules, and velocity calculation module. The simulated phase current waveforms and velocity curves agree well with the tested phase current waveforms and velocity curves experimentally. It is shown that the proposed nonlinear simulation model of the three-phase 6/4 structure switched reluctance linear launcher system is valid.

Temperature Distribution Analysis of a Switched Reluctance Linear Launcher

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.