High Bs Ferrite Material for high power applications High Bs...Alex Goldman: modern ferrite...

High Bs Ferrite Material for high power applications

JC SunBs&T Frankfurt am Main GmbH

19. March 2019APEC 2019 Anaheim (CA)

1Bs&T Frankfurt am Main GmbH

physicist & engineer

make and design ferrite 3Cx and 3Fx

sales amorphous metals 2605/2714/2705

marketing nanocrystalline 500F components

Bs & T Frankfurt am Main GmbH

JC and his...

2Bs & T Frankfurt am Main GmbH

content

• Introduction Bs&T

• Demand on ferrite material development

• Need for high power application

• High Bs material for high power and high frequency application

• Material design route (high Bs and low loss)

• Conclusion


Bs & T Analyzer


Sinus Magnetization AC Pulse Magnetizationhigh excitation low excitation fast transit of magnetic state

IEC 62044-3 IEC 62044-2 dB/dt

loss, µa driven by B mode IEC 60367-1 Annex G

Bpeak, loop driven by H mode

DC superposition

BsT-Pro BsT-Pulse

loss map (f, B, T, HDC) µrev differential and amplitude L,

major, and biased minor loop energetic L, power loss i.e. Q factor

Bs & T Analyzer


Square Wave

Demand on ferrite material

• Driving forces for development of ferrite material

information and communication technologyenergy digitalization

• High power and power density application require new materials outside of the conventional power ferrite material performance factor map


Soft magnetic behavior

• „Good“ soft magnetic behavior:large magnetization changes as a result of very smallapplied magnetic fields ~ high permeable material

easy rotation of magnetization vectoreasy motion of domain wallhigh versatility

• „Ideal“ soft magnetic material:magnetically isotropic and structurally homogeneous, no crystallographic easy axis, no defects, no grainboundary, no internal stress, no magnetostriction


Design consideration of softmagnetic materials

• Intrinsic material properties, depend only on chemical composition (unaffected by the microstructure), are:Tc, Bs and crystalline anisotropy K1, λsselective choice of the chemical composition

• Structure sensitive properties are:Hc, Br and permeability µproper processing route

The most important microstructural parameters are: grain size, crystallographic texture, lattice defects volume fraction, as well asthe size and chemical nature of non-magnetic inclusion and internal stresses


Performance factor 300 mW/cm3 @ 100°C material

map

nanocrystalline

Alex Goldman: modern ferrite technology


Component design consideration for material choice

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Correlation magnetic component, core and material

component core material

High power application for high voltage

• P = U I

• High U; U = dB/dt

• Large I; low permeable cores(powdered, gapped, stress annealed artificial processed)

• Need for magnetic component is high flux linkage, corresponding to large accessible working flux density

• High Bs material


How to achieve the highest

Bs MnZnFerrite material ?

Zaspalis 2013 13Bs&T Frankfurt am Main GmbH

State of art methodology D9BAchievement !

600 K

High power density application for high frequency

• High switching frequency requires high resonance frequencySnoek’s fR ~ Ms / µ

Ms/Bs should be as high as possible (coherent), at same time the µ should be as low as possible

• Key issue is heat dissipation @ MHz

how much do we know about material properties likeresistivity and permittivity ?


Example: resistivity for high frequency

the dc resistivity roughly scales as the resistivity of the grain boundaryRg: V2O5, Nb2O5 Rb: SnO2 , SiO2, CaO, TiO2, CoOCb: Ta2O5

IEEE TRANSACTIONS ON MAGNETICS, VOL. 50, NO. 1, JANUARY 2014


High frequency ω→++Rg

Low frequency ω→0Rg + Rb


Loss at (very) high frequency (MHz)

F.Fiorillo INRIM 2010

VNA

fluxmetric

Chemistry dopants for high resistivity

Resistivity on grain 3F3

Resistivity on boundary 3F4

Number of publication ICF 6 /7 about dopants are available


https://www.google.de/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwju2PXhpOHeAhXJsaQKHWRRDqwQjRx6BAgBEAU&url=http://jugendamt-bonn-erfahrungsbericht.de/wett-strategien/kicktipp-lizas-welt.html&psig=AOvVaw1o7WjZ29OTN4DnZISDDj19&ust=1542745378195643

High Bs ferrite material for future application

• Either high power, or high frequency ferrite material needs highest possible Bs, which is limited by physics (antiferrimagnetism)

• Highest Bs ferrite material for high voltage application. The benefit in combination with the largest possible size as monolith in favor of high power magnetic component design (core height 5 inch, and length of 8 inch)*, commercially available

• Highest Bs ferrite material is essential for application of the highest possible resonance frequency: trade-off MnZnFerrite vs. NiZnFerrite

• High resistivity with comprehensive investigation with number of dopants at expense of Bs has been studied since decades, the chemical composition is just only one consideration, the morphological optimization is process related for loss performance

• Resistivity @ applied frequency and operation temperature have to be firstly specified as material properties

* IEEE September 2018Recent Ferrite material development for high power application


Requirements on material are: high Bs and low loss (large DC biased high frequency rippled AC loss)

• more capability 20% than reference ferrite material to handle more power

• Curie temperature over 600 K is more thermal stable than reference ferrite material

• Less permeability, less air gap length, less fringing, less component loss than reference design


Targeted application: buck


Example: more power handling capability and better

thermal stable compared with reference design

Conclusion

• MnZnFerrite material for high voltage WBG power semiconductor is commercial available, its power magnetic component can be charaterized by BsT-pulse(damped oscillation) funded by EU H2020 and VDE DIN-Connect, dB/dt provides useful assignments of magnetization inductance and current

• MnZnFerrite for high frequency application is still vague, and under development, the most critical part is experimental approval by suitable measuring technique due to problem with thermal inequilibrium, BsT-SQ can be a help (GaN bridge loss tester)


https://www.google.de/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiWqazs6MzdAhUJjLwKHbuVAlAQjRx6BAgBEAU&url=https://recirculasolutions.com/en/recircula-solutions-win-sme-instrument&psig=AOvVaw1CBzvchhuvmiJGQMTmYvjI&ust=1537644104576410https://www.google.de/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiN7dzI7MzdAhXn4IUKHfXwBcoQjRx6BAgBEAU&url=http://andersen-marketing.de/event/din-connect-der-pitch/&psig=AOvVaw2Y5NVn10ccQuXlbJ6iIpjF&ust=1537645109946904

Annex 1 measuring data for simulation


BsT-Pro 2016BsT-SQ 2018

BsT-Pulse 2017

BsT-ProBsT-SQ

BsT-Pulse

Annex 2 BsT-Pulse


1. assignment inductance vs. current NOT unique

2. Voltage decay pending on DUT

https://www.google.de/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiWqazs6MzdAhUJjLwKHbuVAlAQjRx6BAgBEAU&url=https://recirculasolutions.com/en/recircula-solutions-win-sme-instrument&psig=AOvVaw1CBzvchhuvmiJGQMTmYvjI&ust=1537644104576410

Annex 3 BsT-SQ with Herbert Curve


mW

µs

Annex 4 Diverse D.U.T.s

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Power ferrite Fe amorphous

metal alloyed powder “HF” ferrite

High Bs Ferrite Material for high power applications High Bs...Alex Goldman: modern ferrite...

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