# Jeffrey Hwang Winning by Power Alland Chee, Elvis Lin, Joe Wong and Jeffrey H. Hwang Design a 100W PFC Boost Inductor.

## Presentation on theme: "Jeffrey Hwang Winning by Power Alland Chee, Elvis Lin, Joe Wong and Jeffrey H. Hwang Design a 100W PFC Boost Inductor."— Presentation transcript:

Jeffrey Hwang Winning by Power Alland Chee, Elvis Lin, Joe Wong and Jeffrey H. Hwang Design a 100W PFC Boost Inductor

Jeffrey Hwang Winning by Power Criteria of Selection Size Efficiency Cost

Jeffrey Hwang Winning by Power R=S: [ ] Magnetic Reluctance=The resistance of a material to a magnetic field Φ: [Weber] Magnetic Flux=A measure of quantity of magnetism. B: [Tesla]=[ Gauss ] Magnetic Field=Flux Density=Magnetic Induction H: [ ] Magnetic Field Strength=Magnetic Force=MMF per length Review Important Magnetic Variables and Important Magnetic Constants 1[Tesla]=1[Weber/Meter 2 ]=10 4 [Gauss]=1[Newton/(Ampere x Meter)] 1[Weber]=1[Wb]=10 8 Maxwell [L]=1[henry]=1[Volt x Sec/Ampere]=1[Wb/Amp] μ 0 =Air Permeability Constant=4π x 10 -7 [Tesla Meter/Ampere]

Jeffrey Hwang Winning by Power R=mmf /Φ B =NI/Φ B = ι m/ (A c μ) R e =R l + R air = ι m/ (A c μ) + ι air/ (A c μ air )= Φ B = L=N Φ B /I=N 2 / R e = Important Magnetic Formula B=μ H= μ x mmf/l eff = Φ B /A c = μ x N x I/l eff = L x I/(N x A ac)

Jeffrey Hwang Winning by Power B max = Constant @ given material PC95:Bmax~350mT PC44:Bmax~300mT PC40:Bmax~270mT

Jeffrey Hwang Winning by Power NI max = Constant @ l air, air gap is fixed

Jeffrey Hwang Winning by Power Sundest, MPP, Ferrite…? Experiment 1st: Selecting the best Magnetic Material

Jeffrey Hwang Winning by Power Selecting Magnetic Materials Ferrite and MPP have the higher efficiency performance. Ferrite is our selection.

Jeffrey Hwang Winning by Power Ferrite is our selection for Po=100W Ferrite is Cost Effective and Ferrite Core Loss (AC Loss) is much less DCR seems dominates the efficiency with Ferrite Core! Let us prove it here!

Jeffrey Hwang Winning by Power 290uH or 1mH? Experiment 2nd: DCR and switching frequency is fixed Winding Factor is not optimal.

Jeffrey Hwang Winning by Power With fixed DCR=0.46 ohm and fixed fsw=67.5Khz, Po=100 W and Vo=19V AC Adapter Higher Efficiency with Higher Inductor ? but it is miss-leading!

Jeffrey Hwang Winning by Power We have learned: Without the Space Limit, Higher inductance will have the higher efficiency.

Jeffrey Hwang Winning by Power Should we go higher frequency to solve the space issue? Experiment 3th: With RM8 and RM6, we fixed crest factor, r=0.95 and Winding Factor is Optimal with the giving bubbin.

Jeffrey Hwang Winning by Power Po=100W, PFC boost Only Constant r=crest factor=Ip-p/Irms=0.95 with Constant r=0.95 Higher Efficiency with Higher Inductance ? Higher Efficiency with Lower Frequency? Again, it is miss-leading! From above data, to improve efficiency, we only know that we should reduce frequency to trade efficiency.

Jeffrey Hwang Winning by Power We have learned: With the given space, frequency should be as low as possible before the core is saturated. The Lower Frequency provides the Higher Efficiency

Jeffrey Hwang Winning by Power What will happen with fixed switching frequency? Experiment 4 th : Optimal Winding Factor for RM8 and fsw = 67.5Khz

Jeffrey Hwang Winning by Power fsw=67.5Khz with CM6800 100W demo board L=442uH is the Highest Efficiency one; Crest Factor, r~1

Jeffrey Hwang Winning by Power fsw=100Khz with CM6800 100W demo board L=295uH is the Highest Efficiency one; Crest Factor, r~1

Jeffrey Hwang Winning by Power fsw=100Khz with CM6800 100W demo board L=295uH is the Highest Efficiency one; Crest Factor, r~1

Jeffrey Hwang Winning by Power fsw=67.5Khz with CM6805 100W AC Adapter L=295uH is the Highest Efficiency one; Crest Factor, r~1.55

Jeffrey Hwang Winning by Power We have learned: Crest Factor, r~1 to 1.55 L=442uH to 295uH for 67.5Khz and L=295uH for 100Khz gives the best efficiency; It means without saturating the core Reducing DCR, Reducing lg, Reducing N, all will improve the efficiency.

Jeffrey Hwang Winning by Power Conclusion: Ferrite: PC95 RM8 (67.5Khz) --- > RM6 (100Khz) 295uH with CM6805 (PFC+PWM combo IC)

Jeffrey Hwang Winning by Power 442uH with fsw = 67.5Khz Vout = 220V, Po = 100W, RM8 and PC 95 lg = 24 mil N = 52.5 turns Pin max = 146.56W L = 400.58uH x 1.09 Al = 0.1584uH/turn ^2 Ipeak at Sat = 2.3A DCR = 0.09 ohm P core loss ~ 0.39W at Pin max P copper loss ~ 0.228W at Pin max Total P loss ~ 0.62W at Pin max Wire Area = 0.44 mm^2 => AWG=21

Jeffrey Hwang Winning by Power 295uH with fsw = 67.5Khz, Vout = 220V, Po = 100W, RM8 and PC 95 lg = 20 mil N = 40.5 turns Pin max = 138.6W L = 285uH Al = 0.1738uH/turn ^2 Ipeak at Sat = 2.178A DCR = 0.05 ohm P core loss ~ 0.39W at Pin max P copper loss ~ 0.12W at Pin max Total P loss ~ 0.51W at Pin max Wire Area = 0.57 mm^2 =>AWG=20

Jeffrey Hwang Winning by Power 295uH with fsw > 100Khz, Vout = 220V, Po = 100W, RM6 and PC 95 lg = 32 mil N = 64.5 turns Pin max = 118.93W L = 229uH x 1.23 Al = 0.068uH/turn ^2 Ipeak at Sat = 1.87A DCR = 0.19 ohm P core loss ~ 0.15W at Pin max P copper loss ~ 0.33W at Pin max Total P loss ~ 0.48W at Pin max Wire Area = 0.18 mm^2 =>AWG=25

Jeffrey Hwang Winning by Power 100W AC Adapter without SR Efficiency vs. Load With 295uH(RM8), 442uH(RM8) and 303uH(RM6) at fsw = 67.5Khz

Jeffrey Hwang Winning by Power 100W AC Adapter without SR Efficiency vs. Vin With 295uH(RM8), 442uH(RM8) and 303uH(RM6) at fsw = 67.5Khz Po=100W Po=66W

Jeffrey Hwang Winning by Power 100W AC Adapter with SR and without SR Efficiency vs. Vin With 442uH(RM8) at fsw = 67.5Khz Measure the Efficiency Data at the end of cables.

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