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Purpose - The purpose of this paper is to suggest a procedure which makes it possible to reduce the radial vibrations of doubly salient switched reluctance motors (SRMs). Design/methodology/approach - An analytical method for the SRM radial vibration determination is first described. It is then extended to the active vibration reduction. An auxiliary winding equips the stator. The paper explains how the corresponding currents have to be adjusted to achieve a simple and robust control, with a special emphasis about the compatibility of the main and auxiliary supplies and about the reduction control principle. At last, an example of drastic noise reduction is presented. Findings - The proposed method makes possible to define the theoretical vibration spectrum of SRM and thus it gives the major components to be reduced. The feasibility of automating the principle of active reduction is shown. The process of active reduction shows that a vibration component can be diminished by over 90 percent. Research limitations/implications - The active reduction is applied for reducing one component of the vibration spectrum. Future developments will focus on the simultaneous reduction of several components of vibration spectrum. Originality/value - The method offers an automated process to reduce considerably the component of highest amplitude in the vibration spectrum. [ABSTRACT FROM AUTHOR]

Purpose - The purpose of this paper is to present a coupled finite element (FE) - reluctance network model for a hybrid step motor. Design/methodology/approach - The equivalent permeances of the air-gap are determined by 2D nonlinear FE computations. The results of the 2D model are used in a 3D analytical model. A spectral decomposition and a nonlinear fitting of the amplitudes of the permeance harmonics are performed to account for both saturation and high order harmonic effects. The nonlinear resolution of the circuit equations is performed with an iterative process. The performances are determined by using the principle of virtual works. Findings - The method is validated with a 2D FE computation and then applied to a 3D hybrid step motor. Originality/value - The proposed method enables fast and efficient computations of the performances of hybrid stepping motor. [ABSTRACT FROM AUTHOR]

Purpose - The purpose of this paper is to develop a reluctance-resistance network (RRN) formulation for determining the induced current distributions in a 3D space of multiply connected conducting systems. Design/methodology/approach - The proposed RRN method has been applied to solve Problem No. 7 of the International TEAM Workshops. The induced currents in the conductive plate with an asymmetrically situated "hole" have been analysed. The RRN equations have been formed by means of the finite element method using the magnetic vector potential A and the electric vector potentials T and T0. The block relaxation method combined with the Cholesky decomposition procedure has been applied to solve the resultant RRN equations. Findings - Comparison with results published in literature has demonstrated high accuracy of the proposed RRN computational scheme while offering significant savings in computing times. Originality/value - A novel formulation of the RRN approach has been proposed and demonstrated to be computationally efficient. [ABSTRACT FROM AUTHOR]

Purpose - The purpose of this paper is to compare torque calculation methods when a non-conforming movement interface is implemented by means of Lagrange multipliers. Design/methodology/approach - The following methods are here used for computing the torque in a synchronous machine and in a switched reluctance motor: Arkkio's method (AM), local Jacobian matrix derivative (LJD) method, Maxwell stress tensor method (MST) and co-energy variation method. Findings - This paper shows that, the numerical stability produced by Lagrange multipliers yields a stable torque result, even in thin airgap machines if AM, LJD method or MST method are used. Originality/value - This work presents a comparative study to indicate the performance of the most commonly used torque calculation methods, when a non-conforming technique is used, considering a small displacement of the rotor, which is necessary for dynamic cases or coupling with circuit. [ABSTRACT FROM AUTHOR]

Purpose – This paper seeks to study the feasibility of a stator vibration damping using piezoelectric (PZT) actuators applied to switched reluctance motors (SRM). Design/methodology/approach – A single-phase structure without moving rotor, but with the same shape as an SRM stator, is introduced to simplify the study and the experimental measurements. Both analytical and finite element methods are used to detail the chosen location and design of the PZT actuators for this structure. Findings – Experimental results show that PZT actuators with a low voltage allow the decrease of the vibration level due to the electromagnetic forces. Research limitations/implications – To decrease the vibration level of the SRM stator in the real use of the machine, a closed loop system is necessary. Future works consist of the design of a closed loop numerical controller using an acceleration sensor as strain information. Practical implications – The proposed damping method gives a new solution for the SRM noise problem that can be useful for people working on noise reduction on this machine. Originality/value – So far vibration damping of SRM stator was obtained using a command or a geometry "acoustically" optimised, or active vibration with an auxiliary coil. The solution presented here applies PZT vibration damping to the stator with a thickness more important than the one of classical plates used for PZT damping applications. [ABSTRACT FROM AUTHOR]