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Design Considerations for Switched Reluctance Machines
Published in Berker Bilgin, James Weisheng Jiang, Ali Emadi, Switched Reluctance Motor Drives, 2019
The stator and rotor of an SRM are generally made of individually insulated electrical steel laminations to reduce the eddy current losses. The applied insulation coating as well as imperfect manufacturing and assembly processes bring in another key parameter; the stacking factor. The stacking factor for either the stator or the rotor of an SRM is the ratio of the total thickness of the lamination sheets to the axial length of the iron core, which can be calculated as: () Sf=NlamtlamL
S
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
stacking factor a design factor for the core of an electromagnetic device that accounts for the effects of the insulating material on the surface of laminations. The stacking factor gives the percentage of cross-sectional area of the core that is actually ferromagnetic material. Usually expressed as the ratio of the thickness of the laminations without the coating to the thickness with the coating. stall a pause in processing instructions in a pipeline, usually caused by a data dependency or resource conflict. Instructions in the pipeline before the condition causing the stall are prevented from proceeding through the pipeline. standard additive model (SAM) a fuzzy system that stores IF-THEN rules that approximate a function F : X Y . In a simple SAM, the rules may have the form "IF x = A j THEN y = B j ," where x X , y Y , and A j , B j are fuzzy sets. The SAM then computes the output F(x) given the input x using a centroidal defuzzifier. An example of a centroidal defuzzifier is F(x) = a j (x)c j , a j (x)
Magnetic Characteristics
Published in S.V. Kulkarni, S.A. Khaparde, Transformer Engineering, 2017
The processes of slitting, cutting, and punching result in edges having burrs, which not only worsen the stacking factor but also result into short-circuiting of adjacent laminations, and therefore an increase in the eddy loss occurs. The upper limit of an acceptable burr level is about 20 microns. A low burr level improves the stacking factor of the core and reduces its loss. A high stacking factor (which is typically about 0.97 to 0.98) increases the core area leading to a cost-effective design. The staking factor, which is decided by the lamination coating and burrs, is different than the space factor (≈ 0.88 to 0.90) which is defined as the useful magnetic area divided by the area of the core circle. Burrs can be removed by passing the laminations through a de-burring process. A thin coating of varnish may be applied at the edges to cover up the scratches developed during the de-burring process.
A Model for Stator Eddy Current Losses Due to Axial Flux in Synchronous Generators at Steady State and under Load Angle Oscillations
Published in Electric Power Components and Systems, 2021
Birger Marcusson, Urban Lundin
Generators G3 and G4 have been used only for the analyses of the effects of the machine size on losses at steady state. Generator G3 differs from G1 by having a longer and laminated rotor core and partly other materials. Generator G4 is G3 upscaled a factor 1.2 in every direction. Within the radius rlim = 1565 mm in G3 and rlim = 1878 mm in G4 in the stator core, the relative permeability is 100 in the x and y directions and 9.3262 in the z direction, corresponding to a stacking factor of 0.9. The lower permeability in the teeth is realistic at flux densities of around 1.9 T according to extrapolation of data for nonoriented steel M350-50A [17]. The rotor core is axially equally long as the stator core. In addition, eddy currents in G3 and G4 have only been calculated in the clamping structure and the end of the stator core so that a slightly finer mesh could be used. The core end length with eddy currents has been chosen to be 8% of the core length, i.e. 12 mm for G3 and 14.4 mm for G4. Finite element size specifications are the same for G3 and G4 in the air gap and the eddy current carrying parts except the outer part of the clamping ring. The rms element side lengths are 3.2 mm in the core end, 3.5 mm in the fingers and 4.9 mm in the ring within a radius of 1565 mm in G3 and within a radius of 1878 mm in G4.
Design and Double-Stage Optimization of Synchronous Reluctance Motor for Electric Vehicles
Published in Electric Power Components and Systems, 2023
Erdal Bekiroglu, Sadullah Esmer
The 3D view of the stator and rotor of the designed SynRM with optimized parameters are shown in Figures 15(a) and 15(b), respectively. The stator of SynRM has a 3-phase, 4-pole, 36 stator slots, and double-layer distributed winding structure where the rotor of SynRM has 4-pole, 4-flux barriers. The barrier structure is hyperbolic polyline. The steel type of both the stator and the rotor is M19-24G and the stacking factor is 0.95. The B-H curve of this steel type is shown in Figure 16. The skew technique is used in the stator design. The skew angle is defined as 5°. Torque ripple has been reduced to 9.1% at this skew angle. Figure 17 shows the cross-section view of the stator. The stator skew angle is 0° in Figure 17(a), while the skew angle is 5° in Figure 17(b).