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Exxelia introduces the CCM family at ESA / SPCD 2022

Magnetic components for space applications, optimized for multi output Flyback transformers

SUMMARY

  • Introduction : evolution of magnetic components in space

Definition – How to satisfy it?

  • Part 1 : Family qualification by ESA/CNES

Why choose Technology Flow over QPL products?

Qualification steps.

  • Part 2 : Performance characterization of CCM technology

Thermal behavior.

Frequency response and Current saturation (standard CCM inductors).

  • Part 3 : Optimization for multi output Flyback transformers

The cross regulation problem or voltage deviations on some outputs.

PhD thesis definition – Different stages of work – Present and future results.

  • Conclusion

Components that meet present and future customer needs

 

WHAT IS A CCM?

 

CCM family : INTRODUCTION

 

What are the new technical needs and constraints for specific transformers?

 

First : Applications with more outputs.

Need for more In/Out pins.

More different voltages and power levels.

 

Second : Increase in the power to volume and power to weight ratios.

We can no longer take large safety margins.

  →  need to know all the technical limitations of the product.

Reliability, internal heating, frequency response, current saturation.

 

Third : Development time is getting shorter

Breadboards/Prototypes must work the first time  →  design method must be accurate.

Even specific products must avoid qualification time.

  →  have to be already qualified before BreadBoard/Prototype step.

 

Part 1 : ESA qualification 

 

 

  • CCM family : What is this, and what is it for?

1 technology for 5 shapes

Ferrite circuit around windings wound in a bobbin, cabled on a leadframe and moulded.

For both standard and custom components

Different types of functions : inductors (DMC, CMC), pulse/SMPS/measurement transformers

  →  QPL qualification not adapted  Technology Flow is better

 

  • What is a Technology Flow?

Exxelia must prove that CCM technology is space compliant.

1st step Evaluation (Exxelia), 2d step Qualification (ESA/CNES).

Exxelia has to define : bill of materials / manufacturing process / design rules and list of tests to be performed.

 

Bill of materials

3 key raw materials : Bobbin, leadframe and magnetic circuit.

Other materials : wires, solid insulation, glue/resin/varnish, weld, ink, package.

 

Manufacturing process

3 key steps : winding, cabling, moulding.

Other steps : gluing, assembling, marking, testing, packaging.

 

Design rules

All theoretic actions the designer has to do upstream to prevent surprises downstream.

 

Test campaigns

All those in Charts F4 SG1, SG2 and SG3.

Thermal shocks, Temperature rise, Overload, Soldering heat, Vibrations, Mechanical shocks Operating life, Permanence of marking, Solderability, Terminal strength, Dielectric, Moisture.

 

  • Summary of work carried out

- More than 100 components designed, manufactured, and tested

  many configurations of  functions / shapes / tests.

- Some components destroyed to identify security margins

  on thermal, mechanical, dielectric aspects.

- Evaluation took several years to complete

 Result :  Qualification was successful on first try.

 

  • Conclusion

Respecting BOM, process and design rules qualified  ... Exxelia has the right to offer any function in CCM shapes without any mandatory testing for customer.

 

Part 2 : CCM technology performances

 

 

  • Security margins must be reduced

Maximum permissible loss value  →  leads to internal heating (Tmax <  125 °C).

Maximum operating frequency  →  above resonant frequency component is no more inductive.

Saturation curve  →  which inductor value at which excitation current?

 

  • How can these characteristics be determined ?

We decided to carry out 3 experimental campaigns :

  1. Thermal resistance determination for each of 5 shapes.
  2. Inductance versus frequency curves for standard inductors.
  3. Inductance versus current curves for standard inductors.

 

  • Thermal resistance Rth of CCM4, CCM5, CCM6, CCM20 and CCM25

  • Definition of test conditions

Use of inductors with one winding connected to all pins one side.

 

Measurements in vacuum are very complex.

  →  in natural convection in the air first.

Copper losses (heating source) only.

  →  DC current excitation / measurement of Rwind.

Component on PCB / all pins soldered  / no glue / no copper except for large current paths.

Component in a (pierced) box inside a ventilated oven  / temperature controlled.

 

  • Measurement bench

Measurements realised for each of 5 shapes.

2 L values  /  5 Tenv : 25, 50, 75, 100, 125 and 150°C  / up to 15 meas. points for each Tenv.

 

  • Complements and further work

Results applied for all CCM components  /  We have a math model air convection → vacuum.

3D simulations in progress to validate these curves  …  1st results are promising.

Measurements in vacuum are planned.

 

  • Frequency behavior for CCM4, CCM5, CCM6, CCM20 and CCM25 standard inductors

 

  • Definition of test conditions

Use of inductors with one winding connected to all pins one side.

Constant excitation, between 100µT and 1mT.

Components soldered on a brass plate.

RLC meter calibrated after 1 hour functioning.

 

Measurement device

 

  • Measurements realised for each of 5 shapes

2 L values  / up to 15 meas. points for each inductor value.

 

 

  • Result overview
    • Majority of inductors are usable at least up to 1MHz.
    • All of inductors are usable at least up to 400kHz.

 

  • Saturation behavior for CCM4, CCM5, CCM6, CCM20 and CCM25 standard inductors

 

  • Definition of test conditions

Use of inductors with one winding connected to all pins one side.

0,5 phase shift full bridge DC supply.

DC+AC (300kHz) excitation with duty cycle > 0,5.

ΔI constant as long as no saturation.

Period nb controlled to achieve desired DC current.

L value measured with current rise slope.

 

  • Measurements realised for each of 5 shapes

2 L values  / 2 Tenv, ambiant and 125°C / up to 15 meas. points for each Tenv.

2 types of curves L function of Idc or Imax (Idc+ΔI/2).

 

  • Result overview

Big ≠ between 25 and 125 °C : taking account of thermal behavior of ferrite is mandatory.

Main interest : to detect the beginning of saturation.

 

Part 3 : multi Flyback optimization

 

 

  • What are voltage deviations also named cross regulation problem ?
  1. At nominal point of load, some output voltages are different from theoretical values.
  2. If power level at regulated output varies, some non-regulated output voltages values vary.
  3. Current waveform on some auxiliary outputs is very different from theoretical triangle shape.

 

  • Observation :

The more different output / voltage levels / power levels …

The greater the probability to have voltage deviations.

Actual solution : linear regulators.

  →  more volume/weight, less efficiency, more heating.

 

  • Charge :  Transformer is mostly responsible

Problem seriousness depends on application and even on piece inside a manufacturing batch.

Magnetic root cause (transformer), but power electronics consequence (converter).

  →  need to work in both electromagnetism and power electronics.

 

  • Exxelia decided to manage a PhD thesis on this subject

Aims :

  1. Understand scientific problem, Identify root causes (transformer, other components?),
  2. Find solutions, Take account of voltage deviations in design and manufacturing process

Partners : G2Elab laboratory, D. Motte Michellon student, CNES, Steel Electronique

 

  • PhD step 1 : Understanding the scientific problem, identify root causes

Study of magnetic behavior of several transformers

  →  use of FLUX finite element simulation software

Identification of a circuit model compliant with several softwares (Psim, Spice, other)

  →  extended Cantilever magnetostatic model

Calculation of all output voltages for different transformers/converters

  →  use of Psim circuit software

 

  • Result of analysis :
  •  3/4 problem comes from transformer : magnetic coupling between all secondaries
  •  1/4 problem comes from drawbacks of some other components of converter

 

  • Actions :
  1.   Creating an analytic model to take account of leakage inductances between secondaries,
  2.   Use this model to quick calculate all output voltages.

 

  • PhD step 2 :  Finding theoretical and industrial solutions

We identified relationship between   CCM winding process, couplings between secondaries and voltage deviations.

We identified which other components and which drawbacks are concerned.

For the moment, one method of winding CCM to avoid worst cases of voltage deviations and to minimize variations from one piece to another applied since 01/01/2022 for all designed Flyback in CCM.

In progress, a software to optimize (minimize) voltage deviations and to identify best cases of CCM winding processes.

    →  Increase of know-how for customer benefit.

 

CCM family : CONCLUSION

 

 

  • Whatever the function you need

Component is already qualified  →  Reliability and security.

Many pins  ==  many input/output possibilities.

You know its thermal behavior  →  have a good idea of its energy/power limit.

 

  • For inductor applications

You can have standard or custom components.

You know frequency and current responses.

 

  • For multi output Flyback transformers

Design method focused on :

  1. meeting customer’s need as close as possible,
  2. volume and weight reductions.

 

Understanding voltage deviations  =  problem minimization + ability to assist customer.

 

                                                                CCM technology is well adapted for space   …  and we continue to improve it.

 

 

 

Autor : Bruno COGITORE  –  Jean PIERRE

Magnetic Expert / Innovation  –  Space product Manager  •  Exxelia Magnetics

 

Publié le 05 Oct 2021 par Stephane PERES

EuMW 2017 - stand 190

Ultra low ESR, high RF power and high self-resonant frequency The NHB series is a complete range of MLCC based on NPO dielectric material providing a very high Self Resonant Frequency and limiting the parasite Parallel Resonant Frequencies. The series is available in 1111 size with capacitance ranging from 0. 3pF to 100pF. NHB series offers excellent performance for RF power applications at high temperature up to 175°C @ 500 VDC. The lowest ESR is obtained by combining highly conductive metal electrodes and proprietary of the NPO low loss rugged dielectrics. NHB series is particularly fit for high power and high frequency applications such as: cellular base station equipment, broadband wireless service, point to point / multipoint radios and broadcasting equipment. Typical circuit applications: impedance matching, bypass, feedback, tuning, coupling and DC blocking. 100% invar tuning screws with self-locking system   Invar-36 is a unique Iron-Nickel alloy (64 % Fe / 36 % Ni) sought-after for its very low coefficient of thermal expansion. With 1.1 ppm. K–1 between 0°C and 100°C, Invar-36 is about 17 times more stable than Brass which is the most traditional and common alloy Tuning Elements are made of. The working temperature range in Space is so wide that this property becomes essential for a reliable and stable cavity filter tuning. Self-locking system is a technology commonly used on Tuning Element made of Brass or other soft “easy-to-machine” alloys but is innovative and pretty advanced when applied to hard and tough Invar 36. The design consists of two threaded segments separated by two parallel slots. After cutting both parallel slots, the rotor is compressed in its length in order to create a plastic deformation. Thus, an offset is induced between the two threaded segments which generates a constant tensile stress in the rotor from the moment threaded segments are screwed. High Q Factor Dielectric Resonators Dielectric resonators are designed to replace resonant cavities in microwave functions such as filters and oscillators. Exxelia has developed with support of ESA and CNES, a new high-end dielectric material, E7000 series, designed for high-end filters where high Q factor is requested. E7000 is Ba-Mg-Ta materials based that combines an ultra-high Q factor and the possibility to get all the temperature coefficients upon request. E7000 provides high-performance requested for space use in the frequency range 5 to 32 GHz, and guarantees up to Qxf > 250 000 at 10GHZ. Typical applications: Satellite multiplexing filter devices, radio links for communication systems (LMDS), military radars.

Exxelia acquiert la société américaine DeYoung (DMI)

Exxelia annonce l’acquisition de la société DeYoung Mfg, Inc. (DMI) basée à Seattle, Etats-Unis. DMI est un concepteur et fabricant de produits électromagnétiques de haute complexité pour les marchés de l’aérospatiale, du médical et de l’industrie. “The DMI acquisition directly supports our Magnetics SBU expansion strategy.  DMI’s strategic location in the Pacific Northwest aerospace market provides a key geographic location for driving growth and profitability,” said François Vignaud, Exxelia Magnetics’ SBU VP. “DMI is highly regarded for the quality of its products and the operational performance of its organization. DMI products can be found on most major commercial aerospace platforms, supporting in flight power, lighting and entertainment sub-systems.” “We welcome DMI into the Exxelia Group,” said Exxelia USA President Michael Thomas. “During its 40-plus years in business, DMI has built solid customer relationships with a strong brand reputation in the aerospace, medical and other high-reliability magnetics markets. Acquiring DMI creates the potential for both revenue and cost synergies related to cross selling and procurement savings as we leverage Exxelia Group’s broader global supply chain and operational excellence practices to support DMI’s operations.” According to Martin DeYoung, President & CEO of DMI, “We are excited to now be a part of Exxelia‘s growth and expanded product offerings. The DeYoung’s recognized a shared business culture driven by a passion for quality and customer loyalty. By joining Exxelia Group we achieve a goal of meeting our strategic growth objectives while protecting our long standing relationships with our key aerospace customers and their contract manufacturers.” “This acquisition addresses our aerospace customers increasing requirements for global manufacturing access and timely support” stated Eric DeYoung, VP of Operations at DMI. “Together, we have global reach with the capability to serve our customers – whatever their size, location, or aerospace industry sector with one of the most comprehensive and competitive groups of design and manufacturing capabilities.”
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