Reducing torque ripple of switched reluctance machines by relocation of rotor moulding clinches

Abstract

Switched reluctance machines (SRMs) are of great interest because of their simplicity, low-cost, reliability, robustness, fault-tolerance and extended-speed constant-power operation. However, conventional SRMs suffer from high torque ripples. There exist several methods, which have been proposed to reduce torque ripples. One of the proposed methods is to change the geometric structure of the machine. However, analysis of the state-of-the-art designs show that, despite achieving favourable results in applications, the moulding pins of the machines are normally neglected. A motor that gives positive results may get affected negatively by its random moulding during its manufacturing. In this paper, mitigation of torque ripples in short-pitched SRMs (SPSRMs) and fully-pitched SRMs (FPSRMs) are investigated. Three-phase SPSRM and FPSRM are chosen for this study and the effects of the geometric points of moulding pins in the machines are studied comparatively. Maxwell 2D program is used for the analysis and two different models are compared for both SPSRM and FPSRM. The obtained results show that the torque ripples of the two machines are lower when moulding pins are closer to the rotor position. It is reduced by 2.56% at 10 Amps in the proposed SPSRM and 12% at 6 Amps in the proposed FPSRM. It is also observed that the applied method is more effective in reducing torque ripples of FPSRMs than SPSRMs.

Multi‐layer switched reluctance motors: Performance prediction and torque ripple reduction

“…More details for (4), (6), (7) and (9) As indicated in section II-A, average lengths and cross-sectional areas of flux path required for reluctance determination are usually obtained using flux-lines representation for a typical SRM derived from FEM. More details for (4), (6), (7) and (9) As indicated in section II-A, average lengths and cross-sectional areas of flux path required for reluctance determination are usually obtained using flux-lines representation for a typical SRM derived from FEM.…”

“…[7][8][9][10][11][12] LIST OF SYMBOLS AND ABBREVIATIONS: μ 0 , Magnetic permeability of free space; l g , Air-gap length; A sp , Cross-sectional area of stator pole; L, Axial length of stack; β r , Rotor pole arc; β s , Stator pole arc; P r , Number of rotor poles; r ro , Rotor outer radius; r si , Stator bore radius; r ry , Rotor core outer radius; μ r , Relative magnetic permeability; h sp , Stator pole height; l sy , Half circumference of stator yoke; l ry , Half circumference of rotor core; A rp , Cross-sectional area of rotor pole; h rp , Rotor pole height; A sy , Cross-sectional areas of flux in stator yoke; A ry , Cross-sectional areas of flux in rotor Due to exclusive characteristics of the SRM such as high reliability, simple and rugged structure, large power/volume ratio and appropriate operation for a wide range of speed, it can be selected as a promising candidate for adjustable-speed drives in different industrial applications especially EV.…”

“…However, major drawbacks of the SRM are large torque ripple and high noise and significant research has been completed on design of the SRM in two recent decades to solve these problems. [7][8][9][10][11][12] LIST OF SYMBOLS AND ABBREVIATIONS: μ 0 , Magnetic permeability of free space; l g , Air-gap length; A sp , Cross-sectional area of stator pole; L, Axial length of stack; β r , Rotor pole arc; β s , Stator pole arc; P r , Number of rotor poles; r ro , Rotor outer radius; r si , Stator bore radius; r ry , Rotor core outer radius; μ r , Relative magnetic permeability; h sp , Stator pole height; l sy , Half circumference of stator yoke; l ry , Half circumference of rotor core; A rp , Cross-sectional area of rotor pole; h rp , Rotor pole height; A sy , Cross-sectional areas of flux in stator yoke; A ry , Cross-sectional areas of flux in rotor…”

“…In addition, torque ripple reduction of the multi-layer SRM is discussed only in 15 while significant research has been done to decrease torque ripple in the one-layer SRM. [7][8][9][10] Therefore, electromagnetic modeling and torque ripple reduction of the multi-layer SRM is considered in the present paper. In the following, the MEC model developed for the one-layer SRM is introduced in section II and performance prediction of the multi-layer SRM using this model is then explained.…”

Torque ripple minimization of a novel modular stator switched reluctance motor based on direct instantaneous torque control

“…In the former, increasing the number of phase [6 , 7] , optimizing stator or rotor pole arc [8][9][10] [19][20][21][22][23], which simplifies the system structure and improves dynamic response of output torque according to the reports. Moreover, many scholars have also proposed such as fuzzy control [24,25] , neural network [26] and other intelligent control algorithm.…”