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1、Recent Development of Powder Cores and Ferrite Materials Dr Bao Min Ma Technical Director Asia Magnetics Hong Kong Presented at Santak Shenzhen China August 2 2005 Outline Company Profile and Business Update Fundamentals of Soft Magnetic Material for High Frequency Applications Practical Magnetic Co
2、res for High Current Inductors Low Permeability Kool Mu E Cores and Their Advantages MPP THINZ Washer Cores Hybrid Inductors Summary Magnetics With fifty plus years of experience Magnetics has long been a global leader in the development and manufacture of high performance soft magnetic materials an
3、d components Headquartered in Pittsburgh Pennsylvania Magnetics three production facilities in East Butler Pennsylvania Booneville Arkansas and Xiamen China manufacture powder cores ferrite cores and strip wound cores for end use in a variety of applications Soft Magnetic Materials Powder Cores Powd
4、ered Fe MPP High Flux Kool Mu Sendust Ferrites Mn Zn Ni Zn Tape Wound Cores Magnetic Hysteresis loop The shape of hysteresis loop varies with Chemical composition Processing conditions Measuring temperature Exciting frequency Thus Bs Br Hc i a max and core loss are function of temperature and freque
5、ncy Hysteresis Loops and Applications Push Pull SMPSFeed Forwards SMPS Flyback Regulator Powder Core Advantages 1 Higher Bsaturation 2 Softer Saturation 3 Full saturation at high temperature not shown No Gap Distributed Gap Discrete Gap No Gap Bsaturation Bsaturatio n Gapped Ferrite vs Powder Cores
6、Kool Mu and Ferrite Comparison Soft Saturation Powder Core Structure Uncompacted 1 Compacted 14 550 Schematic Microscopic Views Magnetic Alloy Non magnetic insulating material Distributed air gap Normal Magnetization Curves Kool Mu Permeability H B SATURATION CURVE B H Hdc OPERATING CURVE e L IN H 4
7、 0 B H Curve Permeability Roll off Kool M Powder Core Overview MPP High Flux Kool M Permeability 14 550 14 160 26 125 Core Loss Lowest Moderate Low Perm vs DC Bias Better Best Good Saturation Bsat 7 5 Kilogauss 15 Kilogauss 10 5 Kilogauss Nickel Content 80 50 0 Curie Temp oC 460 500 500 Relative Cos
8、t High Medium Low Available Permeability 14 26 60 125 160 200 300 500 14 26 60 125 16026 60 75 90 125 While each type of Magnetics powder core offers a different advantage below is a comparison of key characteristics Magnetics Powder Cores are excellent as low loss inductors for switched mode power
9、supplies switching regulators and noise filters Powder Cores are available in a variety of types and sizes MolyPermalloy Powder MPP Cores Of the three varieties of powder cores Molypermalloy Powder Cores MPP offer the lowest core loss which make them the best choice for low loss inductors MPP cores
10、are available in eight permeabilities ranging from 14 through 550 Magnetics is the only company to offer 300 and 550 cores Thirty sizes include outside diameters from 3 56 mm 0 140 to 77 8 mm 3 063 Standard stabilization or temperature stabilized as wide as 65 C at 125 C cores are available Other co
11、mmon uses for MPP cores are Chokes Converters and EMI RFI filters High Flux Cores For the smallest core size in dc bias dominated designs High Flux material should be used since it has the highest flux capacity Available in six permeabilities ranging from 26 through 160 High Flux cores are available
12、 in thirty sizes that include outside diameters from 3 56 mm 0 140 to 77 8 mm 3 063 Common applications for High Flux cores are Chokes Converters Inductors Inverters Pulse Transformers and Switching Regulators Kool Mu Cores Kool M powder cores offer a low cost option for applications that require re
13、asonably low losses and reasonably high saturation Kool M material is available as both toroids and E core geometries Other shapes such as U cores are currently in development Typical applications for Kool M powder cores are PFC Chokes Boost Buck Regulators Inductors Output Inductors and Flybacks Ko
14、ol Mu Characteristics The base material is about 6 Al and 9 Si 85 Fe Kool Mu Cores TOROIDS Toroids are available in five permeabilities from 26 through 125 with outside diameters ranging from 3 56 mm 0 140 to 77 8 mm 3 063 E CORES Four permeabilities for Kool M E cores range from 26 to 90 and fourte
15、en sizes are tooled ranging from the EF 12 6 to the Metric E80 size Kool M E cores provide a higher energy storage than gapped ferrite E cores resulting in a smaller core size Permeability vs Temperature Comparison Measured 125 癈癈Temperature 55 35 15525456585105125 Change in Permeability 16 14 12 10
16、 8 6 4 2 0 2 4 High Flux MPP Kool Mu Comparison of Frequency Response 125 Frequency MHz 0 010 1110 Initial Permeability 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 High Flux Kool Mu MPP MnZn Ferrite Composition Map MnZnFe2O4 High Power High Q High Permeability MnZn Processing Flow Diagram RAW MATERIALS POWDR PREPARATION FORMING COMPACTION SINTERING FINISHING INSPECTION PACKING SHIPPINNG MnZn Ferrite Sintering Cycle Using the combination of temperature profile and oxygen content
