R. Arumugam

Switched Reluctance Motor Modeling, Design, Simulation, and Analysis: A Comprehensive Review

Switched reluctance machines have emerged as an important technology in industrial automation; they represent a real alternative to conventional variable speed drives in many applications. This paper reviews the technology status and trends in switched reluctance machines. It covers the various aspects of modeling, design, simulation, analysis, and control. Finally, it discusses the impact of switched reluctance machines technology on intelligent motion control.

Analysis and characterization of switched reluctance motors: Part II. Flow, thermal, and vibration analyses

This paper presents new approaches for certain mechanical characterizations, such as thermal and vibration analyses, of switched reluctance motors (SRMs). The paper presents, in three parts, the modeling and simulation procedure for three-dimensional (3-D) finite-element analysis (FEA)-based flow analysis, flow-analysis-based thermal analysis, and a realistic vibration analysis. Section I documents a computational fluid dynamics (CFD) flow analysis procedure for the evaluation of the air velocity distribution inside the SRM at any speed. Section II presents a prediction method for steady-state and transient thermal characteristics of an SRM, using 3-D FEA. The convection coefficient at various heat-dissipating surfaces inside SRM, which is not a material property, but a quantity that solely depends on the air velocity at the respective surfaces, is the major parameter to be evaluated for an accurate simulation of heat distribution. The results of CFD analysis are used, for the first time on SRM, for this purpose. Windage loss calculation, one of the other applications of CFD, is introduced. Vibration in electric motors is an inevitable, at the same time undesirable, property that originates from four major sources: mechanical, magnetic, applied loads and, to a smaller extent, the associated electronic devices. Section III presents: 1) a thorough numerical study of vibration analysis in SRMs, using 3-D FEA methodology, covering all the above vibration sources except the electronics; 2) a 3-D modal analysis of SRMs including stator and rotor structures, shaft, end shields, bearings, and housing; 3) an unbalanced rotor dynamics analysis; 4) associated harmonic analysis; and 5) a stress analysis under various loading conditions. The 3-D vibration analyses presented in this paper to examine the vibration in SRM as a whole are new additions to SRM vibration analysis. Section IV concludes the paper. Future work in every section is highlighted.

Static and dynamic vibration analyses of switched reluctance motors including bearings, housing, rotor dynamics, and applied loads

This paper presents a thorough numerical study of vibration analysis in electric motors, with particular application to switched reluctance motors (SRMs), using three-dimensional finite-element analysis (3-D FEA) methodology. It covers the major vibration sources: mechanical, magnetic, and applied load. The following analyses are presented. 1) A 3-D modal analysis including stator and rotor structures, shaft, end shields, bearings, and housing. 2) An unbalanced rotor dynamics analysis of the rotor, which is important for deciding on the eccentricity of the rotor mass to ensure that the vibration of rotor and housing is within acceptable limits. 3) A harmonic analysis to identify the range of speeds producing high vibration and noise that should be skipped over quickly during acceleration. 4) A stress analysis under different loading conditions (a simulation of load testing) to predict the deformation of the shaft and rotor. Apart from frequently reported modal analysis on the stator of SRMs in two dimensions, these 3-D vibration analyses are essential to examine the vibration in SRMs as a whole.

Dynamic characterization of switched reluctance motor by computer-aided design and electromagnetic transient simulation

A method for calculating the dynamic characteristics of a switched reluctance motor (SRM) is proposed. The method uses finite-element analysis to estimate the dynamic inductance model as the rotor position changes. On the basis of this model, a simulated SRM circuit is designed by power system computer-aided design (PSCAD) combined with electromagnetic transients and control (EMTDC). The circuit can simulate voltages, currents, dynamic torque, and rotation speed of the SRM.

Ingenious digital controller for switched reluctance motor using Verilog (HDL)

This paper presents an advanced method of position estimation and PWM generation for a switched reluctance motor (SRM) using Verilog. SRM cannot be run directly from the mains and requires a power converter and amicable controller, which must be integrated with the motor. The conventional controllers occupy more space and consume more energy. In this paper, Verilog has been used for the rotor position estimation and PWM generation to control a 3 phase 6/4 pole switched reluctance motor. With this method it is possible to save a considerable amount of energy as well as space in the controller circuits since all the control algorithms are implemented using a single chip. Both voltage and current control techniques are discussed.

Finite Element Analysis Combined Circuit Simulation of Dynamic Performances of Switched Reluctance Motors

A methodfor calculatingthe dynamic characteristics of the SwitchedReluctance Motor (SRM) has been proposed. The inductance of the SRM, which varies with rotor position and excitation current and which solely determines the dynamic performance of the machine, has been estimated from Finite Element Analysis (FEA). A circuit simulation for the dynamic characterization of SRM is performed in the Maxwell SPICE environment using the power of an Electromechanical Structural System (EMSS) tool. An integral approach for electromagnetic field computation coupled with circuit simulation is proposed for the dynamic performance prediction of SRM. Detailedsimulation results for various loadconditions are the highlight of this article. Further, the simulations are compared with equivalent simulations done using pSPICE.

Transient analysis of induction motor using finite element analysis

This paper presents the analysis of the induction motor behavior during transient periods using the coupled electric circuit with two-dimensional finite element electro-magnetic field analysis. The designed geometric dimension of induction motor is modeled in the finite element domain. In the circuit domain, stator conductors are connected in distributed winding pattern and phase windings are connected in delta. Resistance and inductance values are added in series with each phase winding in the circuit domain to account the 3D parameter values in the 2D modeling [S. Williamson et al., 1990 and Pham, TH et al., 1999]. Each rotor conductor is connected in parallel and a resistance is added in the rotor circuit to account the end-ring resistance. The circuit domain degrees of freedom (DOF) (i.e) the winding current, induced e.m.f. in the windings and supply voltage, are coupled with finite element domain DOF (i.e) magnetic vector potential (MVP). The rotor motion is included in this model to get the real time simulation results. The transient performances are found at the starting of the motor with no load, the operation of the motor with asymmetrical excitation of the stator and turn to turn fault condition. Simulated results for a 3 hp, 4 pole, 50 Hz and 3-phase squirrel cage induction motor is presented.

Analysis and characterization of switched reluctance motors

This paper presents new approaches for static, dynamic, thermal and vibration analyses of switched reluctance motors (SRM). At first, it proposes a modified stator geometry to improve the torque profile. Dynamic performance study using general purpose softwares such as Maxwell SPICE and PSCAD is reported. Thermal characterization in SRM, with the knowledge of the path of air velocity vector inside air regions by performing computational fluid dynamics, is systematically documented. A three-dimensional vibration analysis viz., rotor dynamics, harmonic analysis and static vibration analysis, under different loading conditions in 3D FEA is reported.

Two dimensional magnetic and thermal analysis of high speed switched reluctance motor using soft magnetic composite material

In aircraft electric motor driven fuel delivery system, the motor must be characterized by high power density, reliability, less size, less weight and high speed. The high speed operation, fault tolerance, high power density makes switched reluctance motor an ideal candidate for high speed aerospace applications. This paper investigates the application potential of soft magnetic composite material (SOMALOY 500) in high-speed switched reluctance motor. Two configurations (1) all sheet metal (2) all Soft magnetic composite have been studied using finite element analysis to obtain their magnetic and thermal characteristics. The study reveals that the all soft magnetic composite configuration albeit suffers from poor average torque, digress in torque-to-weight ratio from conventional model is not very much and the temperature distribution estimation reveals that the all soft magnetic composite model has better thermal capabilities which makes it a viable alternative in high speed aerospace applications.

Analysis and improvement of torque profile in the switched reluctance drives

This paper reports on three unique methods to improve the torque profile of the switched reluctance motor. The improved stages carried out on the electromagnetic analysis of two - dimensional (2-D) finite element analysis via the mesh refinement process is first presented. The study of rotor geometry modifications is the next method; the importance of rotor pole shaping is justified through rigorous analysis. Simulated torque profiles from the rippled to the smoothened are presented. In the third method achieving a smooth torque profile by the introduction of pole shoes in the stator poles is reported.