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SMAG – Magnetic Property Database for Soft Magnetic Materials 

PMAG – Magnetic Property Database for Hard Magnetic Materials  (aka Permanent Magnets)

WHAT IS NEW in Version 6 of SMAG (Released On 1 Aug. 2020)

  • ~ 3000 B(H) and Core Loss Curves  
  • New B(H) Data Smoother (for fast convergent solutions)
  • New B(H) Data Extrapolator (for robust over-fluxed designs)
  • Accurate, evenly spaced B(H)/Core Loss Data (< 2% away from measured data) 
  • Saturation Flux Density Js for more than 1000 materials 
  • Each Grade’s Data in a Single Excel File

SMAG Handbook : 

  • Discover a superior grade of electrical steel 
  • 143 Carbon Steels    
  •  49 Stainless Steels  

SMAG Materials: 

Searchable by manufacturer, Grade, Js, f, T

DIGEST and INDEX files:

  • Lists Source of Data, Composition, Resistivity, Density, Thermal Conductivity 

Version 6 addresses two outstanding issues – roughness in data and Approach to Saturation.

B(H) data smoother – It is well known that smoothness of B(H) data is essential for obtaining convergent solutions.  The measured B(H) data can be rough at some spots due to errors in measurement, digitization, overheating etc. Roughness in B(H) data slows any  magnetic field solver. If B(H) data is too rough, solution may not converge .     

Roughness causes spurious hidden ripples that are unphysical.  MagWeb recently perfected a proprietary spot-cleaner tool that locates these spurious ripple spots and smooths them locally. Version 6 furnishes spot-cleaned raw measured data to ensure faster convergent solutions. Magweb can return such spot-cleaned, solution-convergent data free, if you send your raw B(H) data to rao@magweb.us   

B(H) Data Extrapolator – At present, B(H) data is measured only up to 1.8T. But in severe duty, machines may be over-fluxed, i.e., operate far beyond measured data – close to saturation flux density Js.  Then the flux will leak from designated paths unknowingly into neighboring structures, causing them to overheat.  

But existing field simulators do not input Js  so they extrapolate ‘blind’. Over-fluxed machines therefore face the century-old problem of Approach to Saturation. Several fertile minds have proposed different approaches over past century. But none of them can estimate Js accurately when the data is too far from it.  Magweb recently developed a model, called Generalized Frohlich Model (GFM), that extracts Js from spot-cleaned measured data.  Version 6 uses GFM to accurately extrapolate all data to saturation. Using such data will result in machines that will perform better in severe duty.

SOME REFERENCES ON B(H) DATA SMOOTHNG:

[1] Liu, L., How the B-H curve affects a magnetic analysis (and how to improve it) , Nov. 2019 , comsol.com,  https://www.comsol.com/blogs/how-the-b-h-curve-affects-a-magnetic-analysis-and-how-to-improve-it/

[2] Rao,,D. K., et al. Effective use of magnetization data in the design of machines with overfluxed regions, IEEE Trans. Magnetics   Vol. 51, No. 7,  July 2015.  pp 6100709.

[3] G.F.T Widger, “Representation of magnetization curves over extensive range by rational-fraction approximations, Proc. Electrical Engineers, Jan. 1969,  pp. 156-160.

[4] Kameari, J., FEM Computation of magnetic fields in Anisotropic magnetic materials, IEEJ Trans. Vol. 126, No.2, 2006 [1] Fujiwara, K., A proposal of finite element analysis considering two-dimensional properties, IEEE Trans Magnetics Vol. 38, No. 2, Mar 2002.

SOME REFERENCES ON EXTRAPOLATION TO SATURATION:

[1] Umenei, A.E., Melikhov,Y., Jiles, D.C., Models for extrapolation of magnetization data on magnetic cores to high fields, IEEE Trans. Magnetics, Vol. 47, No. 12, Dec. 2011, pp. 4707-4711.

[2] Rao,,D. K., et al. Effective use of magnetization data in the design of machines with overfluxed regions, IEEE Trans. Magnetics, Vol. 51, No. 7,  July 2015.  pp 6100709.

[3] Chai, S.H., et al. Extrapolating B-H Curve data using common electrical steel characteristics for high magnetic saturation applications, J. Magnetics, Vol. 20, No. 3, p. 258-264. Sept. 2015. https://hanyang.elsevierpure.com/en/publications/extrapolating-bh-curve-data-using-common-electrical-steel-charact

[4] Jastrzebski, R., Chwastek, K., Analytical expressions for magnetization curves, 2017 Progress in Applied Electrical Engineering, 2017 https://ieeexplore.ieee.org/document/8009019.

[5] Subbiah, A., Laldin, O., Cubic extrapolation of steel magnetization curves for highly saturated electric machines, IEEE Trans. Energy Conversion, Vol. 32, No. 4, Dec. 2017, pp. 1624-1625.