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Vibration and acoustic noise are considered as major factors preventing the widespread use of switched reluctance motor (SRM) drives in industrial and commercial applications. In this paper, a new active vibration cancellation strategy for radial vibration is proposed based on the optimal current switching instants. The mechanical impulse response method has been used to estimate the radial vibration of the stator and an optimization routine was developed to define the optimal instants for phase current switching in such a way that the resulting vibration would cancel the vibration caused by prior switching. Experimental verification was conducted on an 8/6 SRM and the results show significant reduction in the stator radial vibration which in turn contributes to reduction of acoustic noise. [ABSTRACT FROM AUTHOR]

Vibration and acoustic noise in switched reluctance motor (SRM) drives have been investigated and addressed frequently. However, the focus of most the paper is on vibration of the stator frame due to radial electromagnetic forces acting on the stator teeth. In this paper, a comprehensive vibration analysis for a SRM assembly using finite element (FE) method is conducted, which considers the stator and rotor vibrations due to radial electromagnetic force as well as the effect of mechanical coupling on the vibration between the stator and rotor. First, an experimental modal test was performed to extract modal parameters and to observe the coupling effect. The parameters were then used to adjust and validate the FE model that was used to obtain transfer functions for vibration characterization. Using the frequency domain representation of the radial magnetic force vector and the calculated transfer functions, radial and tangential vibration components have been predicted. [ABSTRACT FROM AUTHOR]

The double-stator configuration of the switched reluctance machine (SRM) aims to maximise the energy conversion efficiency by optimising the ratio of motional force to the total magnetic force. Maintaining the attractive features of SRM, the double-stator switched reluctance machine (DSSRM) proves to have higher torque/power density than the conventional SRM, which is a crucial feature for traction applications. The original winding configuration used in DSSRM is the full-pitch winding, which yields high-power density but causes significant heat within the machine's end windings. As end windings do not take part in torque generation, concentrated windings were proposed to reduce the heat as well as to reduce the size, cost, and weight of the machine. This study provides a detailed comparative analysis of the effects that the winding configuration has on the performance of a 100 kW DSSRM, with emphasis on flux density distribution, efficiency, and heat generation. It is concluded that the concentrated windings are a better alternative to the full-pitch windings in DSSRM. [ABSTRACT FROM AUTHOR]

In this paper, thermal modeling and analysis of a 10 kW double-stator switched reluctance machine (DSSRM) is presented. Thermal management is an essential step of the machine design, since overheated windings and cores might destroy the insulation and lead to failure of the machine. A three-dimensional (3-D) finite-element method (FEM) has been used to numerically calculate the temperature distribution in different parts of the machine. Furthermore, to include the use of water as coolant, computational fluid dynamics (CFD) has been utilized. Thermal performance of the prototype is then analyzed at various load conditions. A 10 kW prototype of the DSSRM has been built and the results have been experimentally verified. [ABSTRACT FROM AUTHOR]

In a yet another effort to produce better permanent magnet (PM)-less rotor-winding-less brushless electric motor drives, this paper reports work related to multiphase (m =6) high saliency rotor dual-flat-top alternative current control brushless dc (BLDC) reluctance machine drives. The aim is to produce high torque density, low loss/torque in a PM-less rotor-winding-less machine by full usage of machine windings and core and of inverter kVA. A new derivation of the principle of operation, essential rotary and linear machine topologies, and a 2-D finite-element method (FEM) analysis for torque density and torque pulsations on an already built (6 phase, 6 poles, 35 N $\cdot$m) lab prototype are made available and show promising results. Experimental flux decay test results are presented, which, together with standstill torque measurements, validate the finite-element model. Advanced iron loss computation by finite-element analysis indicates moderate core loss, although high air-gap magnetic flux density and current harmonics occur as a natural behavior of a BLDC machine. Electrical and mechanical parameter identification is followed by the development of a circuit model based on FEM imported data for parameters and by a four-quadrant control strategy proposal. Running experiments (motoring and generating) with speed-reversal and field-weakening modes using a DSpace platform, which drives three three-phase inverters that power a star-connected six-phase BLDC multiphase reluctance machine are presented, thus showing operation with a reduced number of switches in the inverter. [ABSTRACT FROM AUTHOR]

This paper presents an optimal design for the rotor of a double stator switched reluctance machine. The effect of the rotor shape on the torque profile is analyzed first. Due to the nonlinearity of magnetic core and complex geometry, an iterative approach is developed to automatically shape the rotor geometry using static finite element method. The rotor of a 12/8/12 prototype is optimized. Simulation results validate the effectiveness of the optimal design. [ABSTRACT FROM PUBLISHER]

Prediction of acoustic noise distribution generated by electric machines has become an integral part of design and control in noise sensitive applications. This paper presents a fast and precise acoustic noise imaging technique for switched reluctance machines (SRMs). This method is based on distribution of radial vibration in the stator frame of the SRM. Radial vibration of the stator frame, at a network of probing points, is computed using input phase current and phase voltage waveforms. Sequentially, the acceleration of the probing network will be expanded to predict full acceleration on the stator frame surface, using which acoustic noise emission caused by the stator can be calculated using the boundary element method. [ABSTRACT FROM AUTHOR]

Vibration and acoustic noises are viewed as a drawback in switched reluctance machines (SRMs), which prohibit their widespread use in noise sensitive applications. Double-stator SRMs (DSSRMs) can be considered as a solution to this problem by incorporating an improved magnetic configuration, which reduces the radial forces in the machine. This paper compares structural behavior of a DSSRM and a conventional SRM using a multi-physic analysis. An electromagnetic finite-element (FE) method is used to calculate force density at various parts of the stator surface in both machines. These force densities are then used in a structural FE analysis to compute acceleration, deformation, and velocity of the vibrating surface at selected point on the outer surface of the machine. [ABSTRACT FROM AUTHOR]

Origins of vibration in switched reluctance machines (SRMs) are investigated. Accordingly, an input–output model based on the mechanical impulse response of the SRM is developed. The proposed model is derived using an experimental approach. Using the proposed approach, vibration of the stator frame is captured and experimentally verified. [ABSTRACT FROM PUBLISHER]

A novel approach to quickly evaluate the electromagnetic vibration emitted by a permanent-magnet synchronous machine in A fractional-horsepower drive is detailed. Field reconstruction method and mechanical impulse response are used. The impulse response for rapid evaluation of vibrations at critical points is used after the design of a torque and speed controller. The vibration obtained using a three-phase pulsewidth-modulation technique and nonclassic space-vector modulations are compared by simulation results. An optimal choice of the carrier frequency, by an optimization method, for the two modulation techniques allows for a 35% reduction of the vibration in the targeted machine under different operating conditions. The peak-to-peak force-magnitude reduction reaches 8%. [ABSTRACT FROM PUBLISHER]

The main objective of this paper is to provide an efficient computational model for fast and accurate calculation of electromagnetically induced vibrations in electrical machines. Although a three-phase permanent-magnet synchronous machine has been used in this paper, the same methodology can be extended to other types of electric machinery. A brief comparison between the different methods for structural analysis in electrical machines is introduced. The method proposed in this paper uses finite-element analysis in order to extract the impulse responses that are used in calculating the vibration. A field reconstruction method is used for the electromagnetic field analysis. [ABSTRACT FROM PUBLISHER]