EMI filter design

264 Pages·2012·9.924 MB·English

by  Pullen, Timothy M., Ozenbaugh, Richard Lee

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K11985
ISBN: 978-1-4398-4475-5
90000
9 781439 844755
EMI Filter
Design
THIRD EDITION

EMI Filter
Design
THIRD EDITION
Richard Lee Ozenbaugh Timothy M. Pullen
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
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© 2012 by Taylor & Francis Group, LLC
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Version Date: 2011906
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Contents
Preface...................................................................................................................xi
Acknowledgments............................................................................................xiii
Authors.................................................................................................................xv
Terms.and.Abbreviations..............................................................................xvii
Organization.of.the.Book..............................................................................xix
. 1. EMI.Filters
1.1. Introduction........................................................................................................1-1
1.2. Technical.Challenges.........................................................................................1-3
1.2.1. Controlling.Parasitic.Uncertainty....................................................1-4
1.3. Types.of.EMI.Filters..........................................................................................1-4
1.3.1. AC.Filters...............................................................................................1-4
1.3.2. DC.Filters...............................................................................................1-5
1.4. No.Such.Thing.as.Black.Magic.........................................................................1-5
1.5. It.Is.All.in.the.Mathematics.............................................................................1-6
. 2. Why.Call.EMI.Filters.Black.Magic?
2.1. What.Is.EMI?......................................................................................................2-2
2.2. Regular.Filters.versus.EMI.Filters....................................................................2-2
2.3. Specifications:.Real.or.Imagined......................................................................2-3
2.4. Inductive.Input.for.the.220-A.Test.Method...................................................2-7
2.5. 400-Hz.Filter.Compared.with.the.50-.or.60-Hz.Filter................................2-8
. 3. Common.Mode.and.Differential.Mode:.
Definition, Cause, and.Elimination
3.1. Definition.of.Common.and.Differential.Modes............................................3-1
3.2. Origin.of.Common-Mode.Noise......................................................................3-2
3.3. Generation.of.Common-Mode.Noise—Load................................................3-6
3.4. .Elimination.of.Common-Mode.Noise—Line.and.Load..............................3-7
v
vi Contents
3.5. Generation.of.Differential-Mode.Noise?.......................................................3-10
3.6. Three-Phase.Virtual.Ground..........................................................................3-10
. 4. EMI.Filter.Source.Impedance.of.Various.Power.Lines
4.1. Skin.Effect............................................................................................................4-2
4.2. .Applying.Transmission.Line.Concepts.and.Impedances...........................4-5
4.3. Applying.Transmission.Line.Impedances.to.Differential.and.
Common.Modes.................................................................................................4-7
4.4. Differences.among.Power.Line.Measurements.............................................4-8
4.5. .Simple.Methods.of.Measuring.AC.and.DC.Power.Lines............................4-8
4.6. Other.Source.Impedances..............................................................................4-12
. 5. Various.AC.Load.Impedances
5.1. The.Resistive.Load..............................................................................................5-1
5.2. Off-Line.Regulator.with.Capacitive.Load.......................................................5-1
5.3. .Off-Line.Regulator.with.an.Inductor.ahead.of.the.Storage.Capacitor.......5-7
5.4. Power.Factor.Correction.Circuit.....................................................................5-8
5.5. Transformer.Load.............................................................................................5-10
5.6. UPS.Load...........................................................................................................5-11
. 6. DC.Circuit—Load.and.Source
6.1. Various.Source.Impedance..............................................................................6-2
6.2. Switcher.Load.....................................................................................................6-3
6.3. DC.Circuit.for.EMI.Solutions.or.Recommendations...................................6-5
6.4. Some.Ideas.for.the.Initial.Power.Supply........................................................6-5
6.5. Other.Parts.of.the.System.................................................................................6-6
6.6. Lossy.Components............................................................................................6-7
6.7. Radiated.Emissions...........................................................................................6-8
. 7. Typical.EMI.Filters—Pros.and.Cons
7.1. The.π.Filter...........................................................................................................7-1
7.2. The.T.Filter...........................................................................................................7-2
7.3. The.L.Filter...........................................................................................................7-3
7.4. The.Typical.Commercial.Filter.........................................................................7-5
7.5. The.Cauer.Filter...................................................................................................7-6
7.6. The.RC.Shunt.......................................................................................................7-7
7.7. The.Conventional.Filters...................................................................................7-8
. 8. Filter.Components—the.Capacitor
8.1. Capacitor.Specifications....................................................................................8-1
8.2. .Capacitor.Construction.and.Self-Resonant.Frequency................................8-2
8.3. Veeing.the.Capacitor.........................................................................................8-3
8.4. .Margins,.Creepage,.and.Corona—Split.Foil.for.High.Voltage...................8-3
8.5. Capacitor.Design—Wrap-and-Fill.Type........................................................8-5
. 9. Filter.Components—the.Inductor
9.1. Inductor.Styles.and.Specifications...................................................................9-1
Contents vii
9.2. Core.Types...........................................................................................................9-1
9.2.1. Power.Cores...........................................................................................9-1
9.2.2. Ferrite.Cores..........................................................................................9-3
9.2.3. Tape-Wound.Toroids............................................................................9-3
9.2.4. C-Core.Inductors.................................................................................9-4
9.2.5. Slug.Type...............................................................................................9-4
9.2.6. Nanocrystalline.Common-Mode.Cores..........................................9-6
9.3. High-Current.Inductors....................................................................................9-7
9.4. Inductor.Design..................................................................................................9-7
9.5. Converting.from.Unbalanced.to.Balanced....................................................9-8
.10. Common-Mode.Components
10.1. Capacitor.to.Ground.......................................................................................10-1
10.2. Virtual.Ground................................................................................................10-2
10.3. Z.for.Zorro........................................................................................................10-2
10.4. Common-Mode.Inductor...............................................................................10-3
10.5. Common-Mode.Calculation..........................................................................10-7
10.6. .Differential.Inductance.from.a.Common-Mode.Inductor.......................10-9
10.7. Common-Mode.Currents—Do.They.All.Balance?..................................10-10
.11. Transformer’s.Addition.to.the.EMI.Filter
11.1. Transformer.Advantages.................................................................................11-1
11.2. Isolation..............................................................................................................11-1
11.3. Leakage.Current...............................................................................................11-2
11.4. Common.Mode.................................................................................................11-2
11.5. Voltage.Translation—Step.Up.or.Down.......................................................11-2
11.6. Transformer.as.a.Key.Component.of.the.EMI.Package.............................11-2
11.7. Skin.Effect..........................................................................................................11-5
11.8. Review................................................................................................................11-5
.12. Electromagnetic.Pulse.and.Voltage.Transients
12.1. Unidirectional.versus.Bidirectional..............................................................12-3
12.2. Three.Theories..................................................................................................12-3
12.3. Initial.High-Voltage.Inductor........................................................................12-4
12.4. Arrester.Location.............................................................................................12-5
12.5. How.to.Calculate.the.Arrester.......................................................................12-6
12.5.1. Dynamic.Resistance..........................................................................12-7
12.6. The.Gas.Tube..................................................................................................12-10
.13. What.Will.Compromise.the.Filter?
13.1. Specifications—Testing...................................................................................13-1
13.2. Power.Supplies—Either.as.Source.or.Load..................................................13-1
13.3. 9-.and.15-Phase.Autotransformers...............................................................13-2
13.4. .Neutral.Wire.Not.Part.of.the.Common-Mode.Inductor..........................13-3
13.5. .Two.or.More.Filters.in.Cascade—the.Unknown.Capacitor......................13-3
13.6. Poor.Filter.Grounding....................................................................................13-4
viii Contents
13.7. “Floating”.Filter...............................................................................................13-5
13.8. Unknown.Capacitor.in.the.Following.Equipment.....................................13-6
13.9. Filter.Input.and.Output.Too.Close.Together...............................................13-6
13.10.Gaskets..............................................................................................................13-8
.14. Waves.as.Noise.Sources
14.1. Spike...................................................................................................................14-1
14.2. Pulse...................................................................................................................14-3
14.4. Power.Spectrum—dB.µA/MHz....................................................................14-4
14.5. MIL-STD-461.Curve.......................................................................................14-5
.15. Initial.Filter.Design.Requirements
15.1. Differential-Mode.Design.Goals...................................................................15-2
15.2. Differential-Mode.Filter.Input.Impedance..................................................15-3
15.3. Differential-Mode.Filter.Output.Impedance..............................................15-5
15.4. Input.and.Output.Impedance.for.a.DC.Filter.............................................15-5
15.5. Common-Mode.Design.Goals.......................................................................15-7
15.6. .Estimation.of.the.Common-Mode.Source.Impedance.............................15-8
15.7. .Methods.of.Reducing.the.Inductor.Value.due.to.High.Current............15-10
.16. Matrices,.Transfer.Functions,.and.Insertion.Loss
16.1. Synthesis,.Modeling,.and.Analysis...............................................................16-1
16.2. Review.of.the.A.Matrix...................................................................................16-2
16.3. Transfer.Functions..........................................................................................16-5
16.4. Review.of.Matrix.Topologies.........................................................................16-6
16.5. π.Filter...............................................................................................................16-7
16.6. L.Matrix.............................................................................................................16-9
16.7. T.Filter.............................................................................................................16-12
16.8. Cauer.or.Elliptic.Matrix...............................................................................16-13
16.9. RC.Shunt.........................................................................................................16-15
16.10.Filter.Applications.and.Thoughts................................................................16-16
16.11.Single-Phase.AC.Filter..................................................................................16-17
16.12.Three-Phase.Filters........................................................................................16-21
16.13.Low-Current.Wye..........................................................................................16-22
16.14.High-Current.Wye........................................................................................16-24
16.15.Single.Insert....................................................................................................16-24
16.16.Low-Current.Delta........................................................................................16-25
16.17.High-Current.Delta.......................................................................................16-26
16.18.Telephone.and.Data.Filters...........................................................................16-26
16.19.Pulse.Requirements—How.to.Pass.the.Pulse............................................16-26
16.20.The.DC-DC.Filter..........................................................................................16-26
16.21.Low-Current.Filters.......................................................................................16-27
.17. Matrix.Applications:.A Continuation.of.Chapter.16
17.1. Impedance.of.the.Source.and.Load...............................................................17-2
17.2. dB.Loss.Calculations.of.a.Single.π.Filter.......................................................17-2
Contents ix
17.3. Example.of.the.Calculations.for.a.Single.π.Filter.......................................17-4
17.4. Double.π.Filter:.Equations.and.dB.Loss........................................................17-5
17.5. Triple.π.Filter:.Equations.and.dB.Loss.........................................................17-6
.18. Network.Analysis.of.Passive.LC.Structures
18.1. Lossless.Networks............................................................................................18-1
18.2. Network.Impedances.Using.Z.Parameters..................................................18-2
18.3. Network.Admittances.Using.Y.Parameters................................................18-4
18.4. Transfer.Function.Analysis—H(jω).............................................................18-5
18.5. Transfer.Function.Analysis—H(s)................................................................18-7
18.6. Coefficient-Matching.Technique...................................................................18-8
18.7. EMI.Filter.Stability........................................................................................18-10
.19. Filter.Design.Techniques.and.Design.Examples
19.1. Filter.Design.Requirements...........................................................................19-1
19.2. Design.Techniques..........................................................................................19-2
19.2.1. Intermediate.CE.Testing...................................................................19-2
19.2.2. Previous.Experience—Similar.Application...................................19-3
19.2.3. Analysis,.Synthesis,.and.Simulation...............................................19-3
19.3. Filter.Design.Summary...................................................................................19-4
19.3.1. Predesign.Objectives.........................................................................19-4
19.3.2. Define.Design.Flow...........................................................................19-4
19.4. EMI.Filter.Design.Example............................................................................19-6
19.4.1. Design.Process...................................................................................19-6
19.4.2. Define.Peak.Harmonic.Amplitude.................................................19-6
19.4.3. Define.Harmonic.Current................................................................19-8
19.4.4. Define.Filter.−3-dB.Pole-Q.Frequency.for.
Differential Mode.........................................................................19-11
19.4.5. Insertion.Loss.Validation...............................................................19-13
19.4.6. Design.Example.Summary.............................................................19-14
19.4.6.1. Define.Component.Values.............................................19-14
19.4.6.2. Verify.Pole-Q.Frequency................................................19-14
19.4.6.3. Define.Characteristic.Impedance.of.Filter..................19-14
19.4.6.4. Stabilize.the.Filter...........................................................19-15
19.4.6.5. RC.Shunt.dQ.Damping..................................................19-17
19.4.6.6. Series.LR.dQ.Damping...................................................19-19
19.4.6.7. Addition.of.Common-Mode.Choke.............................19-20
19.4.6.8. Define.Common-Mode.Pole-Q.Frequency.................19-22
19.4.6.9. Common-Mode.Damping—dQ...................................19-25
19.4.6.10.Filter.Design.Summary..................................................19-26
19.5. Four-Pole.LC.Structure.................................................................................19-27
19.5.1. Design.Approach.............................................................................19-28
.20. Packaging.Information
20.1. Layout................................................................................................................20-1
20.2. Estimated.Volume...........................................................................................20-3