Linear Switched Reluctance Motor Research Articles

Design and Analysis of a New Improved Force Linear Switched Reluctance Motor for Transit Application

Linear Motors are potential candidates for replacing traditional rotary motors in high-speed transit systems. Linear Switched Reluctance Motor (LSRM) is the widely researched motor for such applications. This paper presents a design for linear switched reluctance motor (LSRM) with an improved propulsion force profile. The proposed motor consists of moving translator for direct drive transmission, without the use of mechanical gears. The stator contains a split-teethed stator structure. The proposed motor has more translator teeth than stator teeth. This paper includes a new design methodology for the proposed combination of stator and translator. The motor is designed and analyzed using 3-D finite-element method (FEM). The proposed motor has been optimized using a parameter-based cumulative deterministic optimization algorithm (PBCDOA) for further improving the force profile. The FEM results demonstrate the effectiveness of the design procedure and better force performance of the proposed topology.

Measurement and Optimization of Performance Parameters of Linear Switched Reluctance Motor Using Finite Element Method

Linear switched reluctance motor (LSRM) has proven its suitability in transit applications due to the advantages of direct drive, low cost and simple mechanical structure. In evolution of LSRM, its force performance is the prime concern for the manufacturers. This factor is mainly governed by its physical design. Force characteristics are quite important for obtaining precise design of the LSRM. Because of its nonlinear characteristics, quantitative measurement method for measuring various parameters of the LSRM has not been generalized. This paper discusses finite element analysis-based design considerations for measuring various performance parameters of the LSRM. The paper incorporates the design studies of the LSRM as per analytical expressions and validated using finite element method (FEM)-based ANSYS/Maxwell software. Finite element analysis includes measurement of force, flux and inductance characteristics of the LSRM. Further, it optimizes the motor parameters for maximizing the thrust force of the motor. The proposed study is crucial in estimating various performance parameters of the LSRM using FEM and propagating the traceability chain in parameter estimation of LSRM using three-dimensional FEM-based model of the motor.

Optimisation of double‐sided linear switched reluctance motor for mass and force ripple minimisation

Linear switched reluctance motors (LSRMs) are attractive machines for industrial applications. Their structure is simple, robust, and low cost. Despite these advantages, LSRMs suffer from inherent high force ripples which induce noise and vibration problems. The force performance of these motors is largely influenced by their geometry. Therefore, the dimensions must be optimised to improve the force performance. The aim of the present work was to determine the optimum dimensions of a double-sided LSRM using non-dominated sorting genetic algorithm-II and multi-objective seeker optimisation algorithm along with a three-dimensional (3D) finite element analysis. The analysis and modelling results are presented, and a laboratory prototype is built. The results revealed that the optimised motor has a higher average force, lower force ripple, and lower total mass

A novel design and electromagnetic analysis for a linear switched reluctance motor

A new structure of a linear switched reluctance motor is proposed in this paper. With the permanent magnet inserted in the movers, the performance of the original motor is improved. An electromagnetic analysis is done by using the finite element analysis. The influence of the permanent magnets in different positions of the movers on the electromagnetic force is investigated. Furthermore, a theoretical analysis is made, based on the Schwarz-Christoffel transformation and the Maxwell stress tensor method. The mathematic model is also made with the consideration of the end effect and the cogging effect. The theoretical result of the electromagnetic force is compared with the simulation result. The comparison shows that the error is limited. The analysis of the flux, the magnetic field, and the inductance is then made. The results confirm that the new structure makes the motor more linearized. The new structure of linear switched reluctance motor can contribute to reducing the ripple in the electromagnetic force.

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.

New adaptive fuzzy sliding mode scheme for speed control of linear switched reluctance motor

This study presents a new control system for a linear switched reluctance motor (LSRM). Type-2 Takati-Sugeno fuzzy system is used for the motor approximation. The uncertain parameters of the motor are described by the lower and upper membership functions. By constructing an integral sliding mode surface, an adaptive sliding mode controller is designed and dynamic stability of the sliding motion is verified using the Lyapunov function. The design of the proposed sliding mode surface is independent of the number of fuzzy rules and thus, computational complexity is significantly decreased. The control system is implemented on a double-sided four-phase LSRM and its performance is demonstrated by means of modelling and experimental results.

Analytical modelling of the linear switched reluctance motor with segmental translator

Because of similar structure and operation principles, the linear switched reluctance motor (LSRM) has all advantages of rotary switched reluctance motor. Also, segmental translator LSRM (STLSRM) has the capability to produce higher output power/weight when it is compared with the conventional LSRM. Due to the high advantages of the STLSRM, electromagnetic modelling of this motor is considered in this study. By the direct solution of the field equations, an analytical model is introduced for the STLSRM by which the static characteristic of flux-linkage with a phase for various phase currents and different translator positions is determined. Having this static characteristic, dynamic analysis of the motor is then carried out based on the phase voltage equation to predict the phase current and instantaneous thrust waveforms. Due to the high speed of the developed model, it can be utilised appropriately for the initial sizing of the machine where accuracy can be traded with time-saving. Applying the proposed analytical model to a typical three-phase STLSRM, simulation results are presented and they are validated using the finite element (FE) calculations.

Sliding‐mode observer based sensorless vector control of LFSPM motor for long‐distance drive system

A new series of linear flux-switching permanent magnet (LFSPM) motors has elicited considerable attention. This series incorporates the merits of the high efficiency of permanent magnet linear motors and the low cost of linear switched reluctance motors for a long-distance drive system. However, the vector control of the LFSPM motor requires an expensive and unreliable linear encoder, which must be as long as the entire railway (or at least the whole linear motor). Such a large encoder will lead to extra costs and will even weaken the benefit of the motor performance. Thus, developing its sensorless control for engineering applications is necessary. Sliding-mode sensorless control has the advantage of strong robustness to parameter variations and external disturbances, as well as high dynamic performance, which is important for long-distance drive systems. The proposed algorithms can extend the minimum operating speed, thereby enabling the motor to work at a lower speed. Both simulation and experimental results are provided for verification.

Instantaneous Thrust Control of the Linear Switched Reluctance Motors with Segmental Translator

The linear switched reluctance machine (LSRM) has all advantages of rotary switched reluctance machine including simple and rugged structure, absence of magnetic material and windings on translator, high reliability and appropriate performance over a wide range of speed. Like rotary switched reluctance motor with segmental rotor, segmental translator linear switched reluctance motor (STLSRM) has capability to produce higher output power/weight in comparison to the conventional linear switched reluctance motors. Due to high advantages of the STLSRM drive, various control algorithms including current control, model predictive control, direct force control, universal control and force distribution function are investigated for the first time to control the instantaneous thrust of this motor. Applying these algorithms to a typical three-phase STLSRM, simulation results are presented and they are compared together from the force ripple reduction point of view.

Multi-Physics Modeling and Numerical Analysis of Tubular Linear Switched Reluctance Motors

This paper proposes a multi-physics modeling and numerical analysis of magneto-mechanical and thermal phenomena of a tubular linear switched reluctance motor (TLSRM) representing a linear stepping motor. Algorithms are developed to study the dynamic performances of TLSRM and investigate the temperatures in different parts in the motor due to the heat generation which causes an increase in the temperature of the machine concentrated particularly in the copper coils. The magneto-mechanical model is based on the nonlinear electromagnetic equations solved using the finite elements method (FEM) and the Macro-Element technique while incorporating the Newton–Raphson algorithm for the magnetic nonlinearity treatment. The validity of this model is checked through a comparison between the predicted displacement results for the TLRSM and the experimental values given in literature. The developed thermal model is solved by FEM where the source term is the power density generated in the coils.

A brief analysis of a bearingless linear switched reluctance motor with mover structural decoupling design

In this letter, based on a structural decoupling design for the mover, a bearingless linear switched reluctance motor is proposed to simplify the levitation force control. This mover is designed to exhibit two decoupling features, one feature is that the levitation field and the armature field is decoupled by separating the levitation part and the armature part using the modular design with an E‐core structure. The other feature is the self‐inductance of the levitation module is decoupled from the mover position in the X‐direction by specially designed size of the levitation module. Based on this simple and decoupled mover structure, the levitation force can be controlled linearly by adjusting the magnitude of the levitation current without the information of the armature current and the mover position in the X‐direction, that is, the levitation current control is a simple scalar control, and the levitation force control and the thrust force control are structurally decoupled. Based on the FEA results, the design and theoretical analysis are verified. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Unitized Design Methodology of Linear Switched Reluctance Motor With Segmental Secondary for Long Rail Propulsion Application

Linear switched reluctance motors (LSRMs) provide an alternative to linear induction motor and linear permanent magnet motor in both vertical and horizontal propulsion applications. This paper attempts to develop a unitized design method of a segmental secondary LSRM, which is characterized by a modular magnetic circuit structure and the independent operation of multimover units. The developed design method is directly performed in linear domain without transforming it to a rotary SRM, which complies with the essential natures of the segmental secondary LSRM, showing that it is capable of delivering more power at the same dimensions compared to the conventional tooth type LSRM. Further, the sensitivity analysis of the critical geometric parameters is performed, and the guidelines for selection of the best dimension parameters are given. Finally, the three-phase and four-phase LSRMs are designed and prototyped, respectively with a 1-m long stator. The experimental results validate the design procedures and analysis above.

Position measurement and control of a thin and compact linear switched reluctance motor with a disposable-film mover

This paper describes the position measurement and control of a thin and compact linear switched reluctance motor (LSRM) with a disposable-film mover. The paper proposes a position measurement method using the combination of the eddy current sensor output and a lookup table based on a previously measured information. The position measurement system based on the method is integrated into the developed LSRM to increase the disposability of the mover. The proposed method is robust to reproducible amplitude variation of the sensor output owing to the deformation of the mover. Experimental results showed that the measurement system can produce reliable position information, with a measurement error of up to 25 μm and a resolution that is better than 10 μm. Finally, the tracking performance of the control system using the measurement system as a feedback sensor is examined experimentally.

Linear Hybrid Reluctance Motor with High Density Force

Linear switched reluctance motors are a focus of study for many applications because of their simple and sturdy electromagnetic structure, despite their lower thrust force density when compared with linear permanent magnet synchronous motors. This study presents a novel linear switched reluctance structure enhanced by the use of permanent magnets. The proposed structure preserves the main advantages of the reluctance machines, that is, mechanical and thermal robustness, fault tolerant, and easy assembly in spite of the permanent magnets. The linear hybrid reluctance motor is analyzed by finite element analysis and the results are validated by experimental results. The main findings show a significant increase in the thrust force when compared with the former reluctance structure, with a low detent force.

High-speed container transport system

Background: The new scope of application for vehicles equipped with magnetic suspension is the fright container transportation. In order to realize the transit potential of the country, the increase in mean speed of the container trains is required.
 Aim: The present work aims to explore the possibilities to develop the high-speed transport system equipped with magnetic suspension for container transportation along Euro-Asian land bridge.
 Methods: As the research tools used methods of situational analysis, computer modeling, transport geography, technical and economic analysis.
 Results: The market analysis results of the transit container transportation have shown that the major challenge for Russian transit development is the constrained traffic capacity of the existing transport corridors. The drastic solution to the problem can be the construction of a new high-speed transport system. The following factors determining the conditions for the creation of the new transport system have been identified: use of transport possibilities of the Azov-Black Sea basin; ensuring accessibility of the northern territories; development of technical solutions for the creation of a transport system with low-cost infrastructure. The combined traction levitation system has been developed based on the extremely simple design of the linear switched reluctance motor. The experimental researches of the full-functional physical model of the transport platform have been performed. The assessment of investment project efficiency has shown that despite the large start-up investment in the track infrastructure, the project has positive economic effect.
 Practical importance: The computer model of the combined traction levitation system based on the linear switched reluctance motor has been designed. The concept of constructing a new transport system is proposed, taking into account the characteristics of the proposed operational region in poorly developed territories. The high-speed route has been proposed connecting the Azov-Black sea basin with the Pacific coastline and completely passing through the territories of Russia including some northern regions. The transit potential assessment has shown that due to the transit time reduction it is possible to attract the container freights with traffic volume of 1,52 million in twenty-foot equivalentunit.

Adaptive fuzzy control method for a linear switched reluctance motor

A new direct adaptive fuzzy speed control method for a linear switched reluctance motor with unknown control gain sign is presented. The proposed control system consists of two parts: a fuzzy system and an adaptive law. Fuzzy system approximates an unknown ideal control law with unknown adjustable parameters. After determination of the control law, an appropriate adaptation law is designed to update the adjustable parameters to achieve control objectives. The adaptation law is designed using the error between the unknown ideal control law and fuzzy control law. Unlike previous works, in this study, the unknown control gain sign is taken as an unknown constant parameter and is determined online by an appropriate adaptation law. Proposed control method along with a fuzzy sliding mode speed control and a proportional integral speed control strategies are experimentally studied and the performance index is used to evaluate each strategy. The robustness of the proposed method to the parameters and external load force change has been verified via simulation and experiments. The results indicate that the proposed control method has an acceptable performance.

Optimal pole width ratio for high force density linear switched reluctance motors

The double salient structure significantly reduces the forces in a linear switched reluctance motor (LSRM). The structure is then optimized for high force densities. The pole width is the key parameter in the double salient structure with this paper focusing on the optimal pole width ratio for a high force density LSRM using qualitative and quantitative analyses and experimental measurements. The qualitative analysis based on a linear flux linkage model shows a maximum average force for various translator and stator pole widths. Then, a finite element analysis (FEA) based parametric modeling method is used to validate the results and to calculate the optimal pole width range. Force measurements then agree well with the FEA results. They both show that the optimal stator pole width ratio is 0.4 to 0.45 and the optimal translator pole width ratio is 0.45 to 0.5 for a high force density in the LSRM. The optimal width ratio does not change with the air gap or slot depth. 摘要 双凸极作为直线开关磁阻电机 (LSRM) 的特征结构对于电机的出力性能有着较大的影响。由于极宽是双凸极结构的关键尺寸, 因此该文从理论定性分析、有限元定量分析和实验测量3个方面探究了提升LSRM力密度的最佳定动子极宽比。利用磁链线性模型定性地分析了定动子极宽如何影响电机平均输出力, 从机理上揭示了定子和动子极宽分别存在使得平均输出力最大的极值点。利用参数化建模方法建立了有限元分析模型, 定量地验证了理论分析的推断并给出了最大平均输出力所对应的最佳定动子极宽比范围。通过实验测量了不同定动子极宽的力曲线, 实验测量结果和有限元计算结果相一致, 从而验证了有限元分析的准确性。有限元分析和实验结果表明：对于提升LSRM力密度的最佳定子极宽比范围为0.4~0.45, 最佳动子极宽比范围为0.45~0.5, 且最佳定动子极宽比范围基本不受气隙、槽深的影响。

Design, Optimization, and Prototyping of Segmental-Type Linear Switched-Reluctance Motor With a Toroidally Wound Mover for Vertical Propulsion Application

Linear switched-reluctance motor (LSRM) is investigated and proved to be an alternative for direct linear driving systems, especially for long-distance transportation applications, such as vertical elevator driving motor. This paper presents the design, sensitivity analysis, and optimization of a toroidally wound mover LSRM with segmental stator. The presented LSRM has much higher copper utilization ratio and flux carrying capability than the conventional LSRM for vertical linear propulsion application. The features of motor performance influenced by various geometrical parameters are described using magnetic circuit and finite element analysis to give the guidelines for selecting the reasonable range of those parameters of this kind of machine. Furthermore, an optimization procedure is performed to obtain the optimal machine dimensions considering active payload ratio and force ripples. Finally, the experimental results from the prototype validate the design procedures and analysis above.

Motion system design of a thin and compact linear switched reluctance motor with disposable-film mover

Motion system design of a thin and compact linear switched reluctance motor with disposable-film mover

Prerequisites for the Creation of a High-Speed Container Transport System

The new scope of application for vehicles equipped with magnetic suspension is the fright container transportation. In order to realise the transit potential of the country, the increase in mean speed of the container trains is required. Objective. The purpose of the work is to explore the possibilities to develop the highspeed transport system equipped with magnetic suspension for container transportation along Eurasian land bridge. Methods. The following methods and analysis have been used as research instruments: case study, computer modeling, transport geography and technical and economic analysis. Results. The market analysis results of the transit container transportation have shown that the major challenge for Russian transit development is the constrained traffic capacity of the existing transport corridors. The drastic solution of the problem can be the construction of a new high-speed transport system. The following factors determining the conditions for the creation of the new transport system have been identified: the use of the Azov-Black sea basin transportation facilities, provision of the accessibility of the northern areas; the development of technical solutions ensuring the design of the transport system with low cost infrastructure. The combined traction levitation system has been developed based on the extremely simple design of the linear switched reluctance motor. The experimental researches of the full-functional physical model of the transport platform have been performed. The assessment of investment project efficiency has shown that despite large start-up investment in the track infrastructure, the project has positive economic effect. Practical importance. The computer model of the combined traction levitation system based on the linear switched reluctance motor has been designed. The concept of the new transport system construction has been introduced taking into account the characteristics of the supposed operating test sites in poorly developed areas. The high-speed route has been proposed connecting the Azov-Black sea basin with the Pacific coastline and completely passing through the territories of Russia including some northern regions. The transit potential assessment has shown that due to the transit time reduction it is possible to attract the container freights with traffic volume of 1.52 million in twenty-pounds equivalent.