Nano-crystalline and amorphous cores Products and applications

Transcription

1 Nano-crystalline and amorphous cores Products and applications Casting issues and developments ZVEI Workshop Dr. Swen Graubner, SEKELS GmbH Berlin

2 Nanocrystalline and amorphous cores Introduction to casting process Alloy-specific properties Some applications Summary

3 Amorphous structure crystalline Ordered structure High density amorphous Short range order No long-range order Some crystalline effects do not occur

4 Amorphous structure metallic glass real glass From:

5 Production of amorphous strip melting furnace induction coil liquid metal 1300 C ceramic nozzle cooling rate: Kelvin/s to (fast) automatic winder casting wheel 10 C amorphous metallic strip, µm speed: 100 km/h (60 mph) One process step from melt to final strip thickness

6 How to grow nano-crystals? Start with amorphous material Heat it up to C Let many small crystals grow BUT stop them from getting too big and to merge! Grain size very important

7 Coercivity [A/cm] Why is nano-crystalline soft magnetic? amorphous nanocrystalline crystalline Zero magnetostriction High Curie temperature Low temperature dependence No Nickel or Cobalt Low losses D 6 1/D 1nm 1µm 1mm Grain size D

8 Coercivity [A/cm] Why is nano-crystalline soft magnetic? amorphous nanocrystalline crystalline Zero magnetostriction High Curie temperature Low temperature dependence No Nickel or Cobalt Low losses D 6 1/D 1nm 1µm 1mm Grain size D

9 Saturation Flux Density [T] Soft magnetic alloys for electrotechnical applications 3 ideal 2 real crystalline (metal) Nanocrystalline powder 1 amorphous ferrite ,000 Coercivity [A/m] Mother nature likes huge varieties (and busy engineers )

10 Applications of amorphous & nanocrystalline cores Power Chokes Common Mode Chokes Current Transformers Power Transformers Saturable Reactors

11 Applications of amorphous & nanocrystalline cores Power Chokes Common Mode Chokes Current Transformers Power Transformers Saturable Reactors

12 Power chokes Power Choke Linear choke Usually for higher currents Stores magnetic energy Smoothens current Inductance with magnetic core

13 Amorphous and nano-crystalline power chokes Important parameters: + High flux density + Low losses + Small component size + Linear L-characteristic

14 Core losses in W/kg Alloys for power chokes Typical core losses (columns) in W/kg (f = 25 khz, B p = 0,2 T) and saturation flux density (circles) of choke materials (losses should be low, flux density high )

15 Core losses in W/kg Saturation Flux Density in T Alloys for power chokes , ,5 0 0 Typical core losses (columns) in W/kg (f = 25 khz, B p = 0,2 T) and saturation flux density (circles) of choke materials (losses should be low, flux density high )

16 L (H) in % Linear chokes with amorphous c-cores Inductance stiffness Air gap can be used to adjust inductance Good energy storage capability Linear L-characteristic ( stiffness ) airgap 100% 75% 50% 25% 0% Amorphous C-Core SiFe-Powder MPP Sendust H in A/cm

17 Applications of amorphous & nanocrystalline cores Power Chokes Common Mode Chokes Current Transformers Power Transformers Saturable Reactors

18 Common mode chokes Common Mode Choke Trick: compensating fields Small size possible No saturation by nominal current Removes noise signals I 1 compensated!!! I 2

19 Common mode chokes Common Mode Choke Trick: compensating fields Small size possible No saturation by nominal current Removes noise signals Non-compensated I 1 I 2

20 Nanocrystalline cores for CMC Important parameters: Damping behavior Permeability Frequency dependence Saturation magnetization Size/weight Temperature stability Price

21 Common mode chokes with nanocrystalline cores VITROPERM is registered trademark of VACUUMSCHMELZE GmbH & Co. KG

22 Applications of amorphous & nanocrystalline cores Power Chokes Common Mode Chokes Current Transformers Power Transformers Saturable Reactors

23 Current transformers I prim I sec R B Current transformer Measuring device Measuring accuracy important Transformation of large primary current into low secondary current Phase error Amplitude error F I prim (t) I sec (t)

24 Current transformer errors Current transformer error sources Phase Error Permeability µ =µ +j µ Losses (layer thickness) Amplitude Error

25 Phase Error [ ] Advantages of nanocrystalline cores for CTs 6,0 5,0 4,0 3,0 2,0 1,0 Nano linear-µ SiFe 50% NiFe 80% NiFe Nano high-µ AC 0,2 AC 1 0, Cost-effective replacement of NiFe cores with improved frequency response + Cost effective replacement of amorphous Co-based cores for DC-immune energy meters

26 Nano-crystalline cores for Current Transformers State of the art: o Nano-crystalline or high-permeability Nickel-Iron (MUMETALL, VACOPERM ) o Clear tendency to nano-crystalline alloys o Established in RCCB in households and precision CTs in electronic wattmeters MUMETALL and VACOPERM are registered trademarks of VACUUMSCHMELZE GmbH & Co. KG

27 Summary There are no really good or bad materials Amorphous and nano-crystalline alloys are an interesting option for several applications Choose the right tool for your problem From: From:

28 Summary There are no really good or bad materials Amorphous and nano-crystalline alloys are an interesting option for several applications Choose the right tool for your problem Be open for new solutions From: From:

29 SEKELS your specialist for Special inductive components Standard cores and components Magnetic applications

30 Thank you for your attention!! Any questions?? SEKELS GmbH Dieselstr Ober-Moerlen Deutschland Tel Fax mail@sekels.de Your technical contact: Dr. Swen Graubner Tel: SGraubner@sekels.de Hall 1.1 Booth F24A All statements, information and data given in this presentation are believed to be accurate and reliable, but are presented without guarantee, warranty or responsibility of any kind, expressed or implied on our part. Published by SEKELS GmbH, Germany. All rights reserved. Any distribution, re-utilization or publication of the data, pictures and diagrams need the authorization of SEKELS GmbH in written form.