High Frequency Magnetics; Black Magic, Art or Science? Magnetics Core Loss. Dr. Ray Ridley. APEC Industry Session on Magnetics

Transcription

1 High Frequeny Magnetis; Blak Magi, Art or Siene? Magnetis Core Loss Dr. Ray Ridley APEC Industry Session on Magnetis Wednesday Marh

2 Introdution Core loss alulations and measurements New ore material needs Need for extensive data Approximations to data Different exitation waveforms Temperature variations Standardized data base proposals 2016 Ridley Engineering In 2

3 Immediate Goals for Core Materials 0.6 T SATURATION MPP 0.3 T LOSS SATURATION LIMITED FERRITE Improvements CORE LOSS LIMITED 10K 100K 1 M 10 M 100 M Frequeny (Hz) Would be nie to at least extend saturation range further 2016 Ridley Engineering In 3

4 B-H Loop and Core Losses B ΔB H Core loss alulations and measurements 2016 Ridley Engineering In 4

5 Core Loss MPP 200u 5000 mw/m3 300 khz 0.1 T 5 W/m Ridley Engineering In 5

6 Core Loss PC mw/m3 300 khz 0.1 T W/m3 > 10 times better than MPP 2016 Ridley Engineering In 6

7 Core Loss Steinmetz Equation P kf x B y Steinmetz equation an be used to approximate the atual loss measurements Three oeffiients define the loss for a given material 2016 Ridley Engineering In 7

8 Steinmetz Equation Limitations P kf x B y Equation assumes urves are 1) Equally spaed with frequeny 2) Equal slopes at different frequenies 2016 Ridley Engineering In 8

9 Modifying the Steinmetz Equation P kf Disrete step hanges in oeffiients from Mag In. a d <100 khz khz >500 khz x B y 2016 Ridley Engineering In 9

10 Steinmetz Equation Changing Coeffiients P kf x B y k x y <100 khz khz >500 khz Ridley Engineering In 10

11 Ridley-Nae Variable Steinmetz Equation Continuously-variable oeffiients with Ridley-Nae formula P ( aln f b) f B Five oeffiients needed to desribe materials Example for Magnetis R material: ( df e) P ( ln f 28.32) f B ( f ) 2016 Ridley Engineering In 11

12 Continuously Variable k Term Magnetis R Material Measured Core Loss Loss mw / m k ln f Measurements Frequeny 0.1 P ( aln f b) f B ( df e) Flux Density T a b

13 Continuously Variable y Term Magnetis R Material Measured Core Loss Loss mw / m y f Frequeny Flux Density T Ridley Engineering In P ( aln f b) f B ( df e) d e

14 Oliver Variable Steinmetz Equation (Powdered Iron Core Material) P ore f a b B B B df B 2 2 Continuously-variable oeffiients with Oliver formula Four oeffiients needed to desribe materials, plus 2.3 and 1.65 exponents subjet to hange with different materials update.pdf 2016 Ridley Engineering In 14

15 Loss Multiplier 5 Core Loss Temperature Variation a a a a a a g( T ) 5T 4T 3T 2T 1T 0 4 Manufaturer s Data Temperature Six oeffiients needed to desribe temperature variation Every material has a different urve Does the urve also hange with frequeny and flux level? 2016 Ridley Engineering In 15

16 Different Core Exitations B B t t B B t Need to modify equations to suit eah of these waveforms 2016 Ridley Engineering In t 16

17 General Triangular Flux Waveform B 2 B DT 1 s D2Ts T s t P( D) DP f D P 1 2 f 2D 2D 1 2 P ( aln f b) ( df e) f B 2016 Ridley Engineering In 17

18 Duty Cyle Core Loss Multiplier 6 B = 0.15 T 5 4 DCM : D ' D CCM : D ' 1 D P( D) DP f D P 1 2 f 2D 2D Ridley Engineering In 18

19 Putting it All Together 2016 Ridley Engineering In 19

20 What We Need from the Manufaturers 1) Raw ore loss sinewave test data over wide range of frequeny, B, temperature 2) Who is going to fund the modeling into a standard format database? 20

21 Magnetis Foreast High-ripple urrent indutor designs will dominate the pratial high-performane market Pratial high performane means onverters up to 5 MHz Core material improvements will be just inremental (unless some breakthrough material emerges) Insuffiient funding is going into fundamental magneti material researh to give a good hane of any breakthroughs. Data Standardization is badly needed from the ore manufaturers to ease onfusion Core loss raw data is needed, not just urves. Creative ore geometries need to be applied to POL indutors and other high-ripple parts Magneti ore will not go away (however muh it is wished for) Isolation transformers will reep bak into PoL appliations to boost effiieny More magnetis! Multi-onverter proessing will ontinue to proliferate Ridley Engineering In 21

22 Some Referenes Cliff Jamerson: Ed Herbert: Targeting Swither Magnetis Core Loss Calulations, Power Eletronis Tehnology, Jan Christopher Oliver: update.pdf Power Supply Design Center Artiles [89] Core Loss Modeling [90] Core Loss Modeling with Non-Sinusoidal Waveforms - Part II [91] Core Loss Modelling - Sinewave Versus Triangle Wave - Part III Ray Ridley and Art Nae [A03] Modeling Ferrite Core Losses Christopher Oliver [A06] Core Loss Modeling & Measurement Power Supply Design Software Ridley Engineering In 22