modeling conducted emi in power electronic systems · 2019. 10. 17. · • commonode (and...
TRANSCRIPT
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Modeling Conducted EMI in Power Electronic Systems
Aaron BrovontAssistant Professor
Electrical and Computer [email protected]
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Contributors & Collaborators
Dr. Rob Cuzner
Dr. Seungdeog ChoiMr. Mark Didat
Dr. Steven Pekarek
Dr. Andy LemmonDr. Aaron Brovont
Dr. Mike MazzolaMr. Jim Gafford
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Outline
• Background on electromagnetic compatibility (EMC)• Conducted emissions testing• Common-mode (and differential-mode) modeling tutorial• Application and validation in UA EMI testbed• Study of leakage current through multi-chip power module (MCPM)
baseplate
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The paradigm shift in power systems due to power electronics makes EMC critical to design.
Ideal, 3-phase 60-Hz voltage supply Two-level, VSI phase-to-neutral output
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Present trends in power electronics likely to worsen EMI.
• Maturation of wide-bandgap devices
• Drive for increased efficiency and/or power density
• Increased penetration of renewables and power electronics applications
• Results: higher edge rates (dv/dt), switching frequencies, and voltage levels
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What is electromagnetic compatibility?
• Concerned with the generation, transmission, and reception of electromagnetic energy
• A system is electromagnetically compatible if1. It does not cause interference in surrounding systems;2. It does not allow interference from surrounding systems;3. It does not cause interference with itself
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Emitter Transmission Path Receptor
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Some basic EMC terminology
• Emissions, interference, and susceptibility• Conducted emissions vs. radiated emissions• Differential-mode vs. common-mode
• Electrical length: – f = 300 kHz, λ = 1 km– f = 3 MHz, λ = 100 m– f = 30 MHz, λ = 10 m– f = 300 MHz, λ = 1 m
• Antennae are poor radiators of signals for which
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Spectra of Modern Power Electronics
102 103 104 105 106 107 108 109
300 MHz
3GHz
Si IGBTOperation
FrequencyRange
WBGOperation
FrequencyRange
Si IGBTExtendedDynamics
Range
WBGExtendedDynamics
Range
VHF UHF
Lumped Element Analysis Increasingly Valid
Lumped Element Analysis Increasingly Invalid
“Near RF”Domain
HF
3MHz
30 MHz
• Traditional IGBT-based systems: • Operation Frequencies to ~50 kHz• Easily-suppressed extended dynamics• Packaging impedances are not critically
important
• WBG-based systems: • Operation Frequencies to a few MHz• Extended dynamics to ~50 MHz• Packaging impedances are critically
important in “Near-RF” domain
A. N. Lemmon, R. Cuzner, J. Gafford, R. Hosseini, A. D. Brovont, and M. S. Mazzola, “Methodology for Characterization of Common-Mode Conducted Electromagnetic Emissions in Wide-Bandgap Converters for Ungrounded Shipboard Applications,” IEEE J. Emerg. Sel. Topics Power Electron., vol. 6, no. 1, pp. 300–314, Mar. 2018.
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Approach to EMI challenges in PE systems
• PE emissions primarily in conducted band (~10 kHz–30 MHz)• Objective is to prevent emissions from reaching grid (large antenna)• Three options: reduce susceptibility, make transmission inefficient, or eliminate
source• Our Approach: Employ modeling to minimize conducted emissions
– Conducted emissions simpler and possible early in design– Reduces potential for radiated EMI
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Conducted EMI predictable Radiated EMI predictable
Early-stage design Late-stage design
Architecture System fabrication
Component topologies
Component selection
System layout
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How do you measure conducted emissions?• Line Impedance Stabilization
Network‡:– Provide a standard source impedance for
evaluating/measuring EUT emissions– Decouple source and EUT emissions– Typically modeled as 50 Ω to ground
• LISN only used on input side of EUT• Commercial LISNs are not available for
voltage levels > 1 kV• Custom LISNs designed and built at
UA
Fischer FCC-LISN-50-XXX LISN
‡ “DOD Interface Standard, Requirements for the control of electromagnetic interference characteristics of subsystems and equipment, Mil-Std-461G, 10 Mar. 2015.
LISNs
Vdc
Zheatsink
Rli
LlCliClo
Rlo
Zg
a
Cug
CpgClg
Cdc
Rli
LlCliClo
Rlo
Q1
Q4
Earth
System Ground
u
l
b
Cug
CpgClg
Q2
Q5c
Cug
CpgClg
Q3
Q6
Zwg
PMSM
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Example: emissions from a machine-driveLISNs
Vdc
Zheatsink
Rli
LlCliClo
Rlo
Zg
a
Cug
CpgClg
Cdc
Rli
LlCliClo
Rlo
Q1
Q4
Earth
System Ground
u
l
b
Cug
CpgClg
Q2
Q5c
Cug
CpgClg
Q3
Q6
Zwg
PMSM
i1
i2v1Pv2P
P
– Differential mode (DM):
– Common mode (CM):
A. D. Brovont and A. N. Lemmon, “Utilization of Power Module Baseplate Capacitance for Common-Mode EMI Filter Reduction,” IEEE Electr. Ship Technol. Symp., 2019, submitted.
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Fields from CM current are more likely to radiate and couple with nearby equipment
• Magnetic field accumulates
Fields fall off for long wires
• Magnetic field cancels
Fields fall off for long wires
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i1i2 i12
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The many faces of the “Common Mode”
• Bearing currents and shaft voltages– Cause premature bearing failure in electric machines with VFDs– Shock hazard and voltage stress on insulation
• Leakage currents– Unintended ground currents typically through capacitive couplings with chassis and heat
sinks– Interference with low-power electronics
• Circulating currents– Steady-state current flow between paralleled converters– Can be large and low-frequency, down to DC– Lossy, can cause instability, and unbalanced power sharing
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DIFFERENTIAL-MODE AND COMMON-MODE EQUIVALENT CIRCUIT MODELING
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Objectives of modeling conducted EMI
• Analytically predict parasitic/undesirable behavior of power electronic systems
• Inform/guide measurements to support modeling and analysis• Predict the impact of new technologies (e.g., WBG devices)• Evaluate methods to mitigate EMI and CM current through design
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i1
i2v1Pv2PP
invnP
iNvNP
vPg
Modified definition for CM voltage enables rigorous & flexible model generation
Common Mode
Differential Mode
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P is arbitrary
A. D. Brovont, "Generalized Differential-Common-Mode Decomposition for Modeling Conducted Emissions in Asymmetric Power Electronic Systems," IEEE Trans. Power Electron., vol. 33, no. 8, pp. 6461-6466, Aug. 2018.
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DM and CM definitions can be viewed generally as a space transformation
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i1
i2v1Pv2PP
invnP
iNvNP
vPg
P is arbitrary
A. D. Brovont, "Generalized Differential-Common-Mode Decomposition for Modeling Conducted Emissions in Asymmetric Power Electronic Systems," IEEE Trans. Power Electron., vol. 33, no. 8, pp. 6461-6466, Aug. 2018.
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Sourceeas Ls Rs
ebs
ecs
LfsLdc Rdc
eal
ebl
ecl
D1 D3 D5 S1 S2 S3
Ldc Rdc
Ls Rs Lfs
Ls Rs LfsD4 D6 D2 S4 S5 S6
Cwgs
LlRlLf l
LlRlLf l
LlRlLf l
Cwgl
DC Bus
Cdc1 Cdc2
Rectifier Inverter AC Load
Rb
Lb
Lb
Cgb
CgbDb
Sb
Buck Converter DC Load
Cwgs Cwgs Cwgl Cwgl
These specific definitions lay the foundation for CM equivalent circuit modeling.
Example microgrid
Reduced CM model
CM equivalent circuit theory
Rl /3Lf l /3iCM,lPvCM,lRs /3 Lfs /3 iCM,s
vCM,s Rdc /2Ldc /2 Pʹ
3Cwgs 3Cwgl
Lb /2iCM,bvCM,b
2Cgb
vCM,dc vʹCM,dc
A. D. Brovont & S. D. Pekarek, "Derivation and application of equivalent circuits to model common-mode current in microgrids," IEEE J. Emerg. Sel. Topics Power Electron., vol. 5, no. 1, pp.1-12, March 2017.
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Why don’t we just simulate mixed-mode circuits?
• Wide range of time-constants• Often a large number of electrical components• Recipe for numerical heartache as number of components increase• Does not give any design insight unless run many simulations and
interpret a lot of data
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OR, why do we need CM equivalent circuits?
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Example: platform developed for in situ emissions characterization of intermediary conversion systems.
Output LISNsInput LISNsEUT
(half-bridge inverter)
Vdc
Rh
Rli
LlCliClo
Rlo
Zg
ACn
Cn
ClgCagCug
Cdc
Rli
LlCliClo
Rlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
Earth
Testbed Ground
iin,cm iout,cmU
L
• Architecture inspired by MIL-STD-461 CE-102
• Terminations at input and output representative of fielded applications
• Platform provides DM and CM model validation environment for EUT
• Employed to study leakage currents through module parasitics
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An example application of the modeling approach
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Half-bridge EMI testbed CM equivalent modelCM equivalent circuit theory
ioii
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
kCpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
cmcm
Rli/2
Ll /2io
2Cli
iivovi
vp
vCp
Zh
(2+k)Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
Acm cm
cm
cmcm
dmcm
Half-bridge configuration of UA EMI testbed
A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
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CM model development in four steps
1. Add important parasitics to MM component models2. Partition MM model around switches3. Transform components to CM equivalent circuits4. Connect component equivalent circuits using CM reference to form
system model
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1) Create the mixed-mode model
Zh
Rli
LlCliClo
Rlo
Rg
P
kCpCpCp
Cdc
Rli
LlCliClo
Rlo
Rlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
N
v 2P
L
U
1 2 3
A
Rh
P
kCpCpCp
v 1P
v3Pv 2
P
1 2 3
vCMp
vm
Rh
(2+k)Cp
P
Left multiply by T3vand sub in (T3i)-1iDCM
2) Partition model around switches
3) Decompose components into equivalents 4) Combine equivalents using CM reference
ioii
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
kCpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
cmcm
Rli/2
Ll /2io
2Cli
iivovi
vp
vCp
Zh
(2+k)Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
Acm cm
cm
cmcm
dmcm
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Step 1: Create the mixed-mode model
• Add parasitics to the standard MM model (if desired or necessary)• Assuming symmetric parasitics for sake of demonstration
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Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
CpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
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Step 2: Partition MM model around switches
Focus on the non-power-electronic elements – partition into groups
25
Zh
Rli
LlCliClo
Rlo
Rg
P
CpCpCp
Cdc
Rli
LlCliClo
Rlo
Rlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
N
v 2P
L
U
1 2 3
A
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
CpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
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Step 3: Symmetric lines transform following simple parallel addition rules in CM.
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Mixed-mode Model CM Equivalent Circuit
i1
i2v1Pv2P
P
vPg
R
R
L
L
CC
i1 ʹ
ʹi2
R/ 2L/ 2icm
2C
PvPg
vcm icm ʹ
A. D. Brovont & S. D. Pekarek, "Derivation and application of equivalent circuits to model common-mode current in microgrids," IEEE J. Emerg. Sel. Topics Power Electron., vol. 5, no. 1, pp.1-12, March 2017.
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Step 3(a) Detail
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Mixed-mode Modeli1
i2v1Pv2P
P
vPg
R
R
L
L
CC
i1 ʹ
ʹi2
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Step 3(b): three-line example
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Parasitic baseplate capacitance
Rh
P
CpCpCp
v 2P
1 2 3
Mixed-mode Model CM Equivalent Circuit
vcm
Rh
3Cp
PLeft multiply by T3vand sub in (T3i)-1idcm
A. D. Brovont, "Generalized Differential-Common-Mode Decomposition for Modeling Conducted Emissions in Asymmetric Power Electronic Systems," IEEE Trans. Power Electron., vol. 33, no. 8, pp. 6461-6466, Aug. 2018.
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Step 3(b) Detail
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Rh
P
CpCpCp
v 2P
1 2 3
Mixed-mode Model
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Step 4: Form system model by specifying reference point(s)
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Rli/2
Ll /2io
2Cli
iivovi
vp
Zh
3Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
A
cm
cm cm cm cm
Rh
Rli
LlCliClo
Rlo
Rg
A
CpCpCp
Cdc
Rli
LlCliClo
Rlo
Rlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
N
v 2A
L
U
1 2 3
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Step 4: Form system model by specifying reference point(s)
• Select shared reference point and connect CM equivalent circuits
• Phase node A is selected in this example
Intrinsic CM voltage sources
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A
Cn
Cn
N
vQ1
vQ2
U
L
vCn1
vCn2
Q1
Q2
Rli/2
Ll /2io
2Cli
iivovi
vp
Zh
3Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
A
cm
cm cm cm cm
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Overall system model
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Half-bridge EMI testbed CM equivalent modelCM equivalent circuit theory
Half-bridge configuration of EMI testbed
Rli/2
Ll /2io
2Cli
iivovi
vp
Zh
3Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
A
cm
cm cm cm cm
ioii
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
CpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
cm cm
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ioii
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
kCpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
cm cm
How to model effects of asymmetry?
• Asymmetry between lines of a CM path produces “mode conversion”
• Introduce an asymmetry factor k in module parasitics to investigate impact
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Mixed-mode ModelDecomposition approach to asymmetric components
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Parasitic baseplate capacitance
Rh
P
kCpCpCp
v 2P
1 2 3
Left multiply by T3iand sub in (T3v)-1vdcm
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Mixed-mode Model CM Equivalent Circuit
vp
vCp
Rh
(2+k)Cp
P
dmcm
vCpcm
Decomposition approach to asymmetric components
36
Parasitic baseplate capacitance
Rh
P
kCpCpCp
v 2P
1 2 3
A. D. Brovont, "Generalized Differential-Common-Mode Decomposition for Modeling Conducted Emissions in Asymmetric Power Electronic Systems," IEEE Trans. Power Electron., vol. 33, no. 8, pp. 6461-6466, Aug. 2018.
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Overall system model
37
Half-bridge EMI testbed CM equivalent modelCM equivalent circuit theory
ioii
Vdc
Zh
Rli
Ll
CliCloRlo
Rg
A
Cn
Cn
kCpCpCp
Cdc
Rli
Ll
CliCloRlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
cmcm
Rli/2
Ll /2io
2Cli
iivovi
vp
vCp
Zh
(2+k)Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
Acm cm
cm
cmcm
dmcm
Half-bridge configuration of UA EMI testbed
A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
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Bonus: Analyze/approximate output CM voltage source
The second term is the CM voltage of the neutral-clamping capacitors. If Cn is large, this voltage is approximately constant:
38
A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
A
Cn
Cn
N
vQ1
vQ2
U
L
vCn1
vCn2
Q1
Q2
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Bonus: Analyze/approximate mode conversion source
The second term is the CM voltage of the neutral-clamping capacitors. If Cn is large, this voltage is approximately constant:
39
A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
Zh
2
kCpCpCp
Cdc
vQ1
vQ2
1
3
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Summary: CM equivalent model of the testbed
Rli/2
Ll /2io
2Cli
iivovi
vp
vCp
Zh
(2+k)Cp
2Clo
Rli/2
Ll /2
2Cli2Clo
Rlo/2 Rlo/2
Rg
Acm cm
cm
cmcm
dmcm
• CM voltage sources dominated by switching– dv/dt & switching frequency critical
parameters
• Voltage ripple at neutral point injected into CM– Self-resonant behavior of Cn must be
avoided (ESL critical)
• Voltage ripple at dc input injected due to mode conversion– Self-resonant behavior of Cdc must be
avoided (ESL critical)
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A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
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APPLICATION AND VALIDATION OF CM MODELING APPROACH
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UA SiC EMI Characterization Testbed Implementation
• Identical, characterized input and output termination impedances
• Natural convection cooling to avoid corruption from thermal management
• Diff. probes and current probes used for utility ground isolation
• Testbed and utility ground connected only through DC supply
• Testbed configured with half-bridge inverter EUT employing Cree CAS120 1.2-kV SiC half-bridge MCPM
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A. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
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Leakage current through MCPM was measured in the EMI characterization testbed.
• Half-Bridge EUT with shorted load (only LISN impedance)†
– Measured displacement current through MCPM baseplate through LISNs on input and output.
– 100 kHz fixed-duty PWM, 300 ns dead time, 600 V DC bus
• Results were compared against nominal model with measured parasitic baseplate capacitances
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†A. Lemmon, R. Cuzner, J. Gafford, R. Hosseini, A. Brovont, M. Mazzola, "Methodology for Characterization of Common-Mode Conducted Electromagnetic Emissions in Wide-Band-Gap Converters for Ungrounded Shipboard Applications," in IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 6, no. 1, pp. 300-314, March 2018.
LISNFilters
LISNInductors
Inverter Core
EMI Characterization Testbed at UA
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Characterizing the MCPM Baseplate Capacitance• Baseplate capacitance was not
measured previously• Cannot be measured from the
terminals• A sample module (Cree
CAS120) from the EMI testbed was deconstructed to accurately quantify the capacitances
44
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CM voltage noise source modeling
• The dominant component of the CM voltage is proportional to (vQ1-vQ2)
• This term is readily modeled from the nominal input voltage, duty cycle, and average rise and fall time of the switch voltage:
45
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Equivalent model reduced and analyzed to predict baseplate current.• The expression for the equivalent CM source with respect
to the baseplate is approximately
• Model indicates strong influence of MCPM parasitic asymmetry and potential compensation†
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Reduced CM Equivalent Model
Ll /4
4Clivbp,eq
(2+k)Cp
4Clo
Zlisn4
Rh
Rli4
Rlo4
cm
A. D. Brovont and A. N. Lemmon, "Common-mode/differential-mode interactions in asymmetric converter structures," in Proc. IEEE Electric Ship Technologies Symposium, Arlington, VA, 2017, pp. 84-90.
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STUDY OF BASEPLATE CAPACITANCE IN MULTICHIP POWER MODULES
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D1 (U) S1D2 (A)S2 (L)
Unbalanced baseplate capacitance is a critical factor affecting leakage current through baseplate.• DBC substrate geometry leads to
capacitive coupling between terminals and baseplate
• High dv/dt drives leakage current through the baseplate
• Low-side source terminal (S2) usually occupies much less substrate area than D1 and S1D2(which are similar)
• In general, D1, S1D2, and S2 substrate areas are all different leading to unequal Cug, Cag, and Clg
49
Cree CAS120 Module - Disassembled
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Relaxed concept of CM voltage and flexible DM and CM definitions permit derivation of CM equivalent model.
50
iout,cmiin,cm
Rh
ibpCug+Clg
Cag
A
vdm→cm
vUL,cm vAN,cmU,L
Zin2
Zout2
iulg,cm
iag
A,N
ul
Output LISNsInput LISNsEUT
(half-bridge inverter)
Vdc
Rh
Rli
LlCliClo
Rlo
Zg
ACn
Cn
ClgCagCug
Cdc
Rli
LlCliClo
Rlo
NRlo
LlCloCli
Rli
Rlo
LlCloCli
Rli
vQ1
vQ2
Earth
Testbed Ground
iin,cm iout,cmU
L
Half-bridge EMI testbed CM equivalent modelCM equivalent circuit theoryA. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Analysis of leakage current through the MCPM baseplate
• The equivalent CM ac voltage driving BP current is given by
where
• In a typical module,
51
vcm,ac
Cbp
Zin2
vcm,dc
Zout2
Rhibp
A. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Experimental setup was devised to validate the CM model predictions.
• Discrete capacitors were placed between the module terminals and the baseplate
• The qac parameter was swept across the range including the “critical” value of 1/4
• Total baseplate capacitance (Cbp) was held constant for all cases
52
External Caps Added for Sweep of qac
A. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Results of the qac sweep experiments
53
• Model accurately predicts BP current RMS amplitude over full sweep
• Cancellation occurs at the qac = 1/4• Model accurately predicts the polarity
inversion and symmetry about the “critical” qac value of 1/4
A. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Model accurately predicts all significant characteristics of the BP current including ringing frequency and amplitude.
54
A. Brovont, A. Lemmon, C. New, B. Nelson, B. DeBoi, "Cancellation of Leakage Currents through Power Module Baseplate Capacitance," in Proc. IEEE Appl. Power Electron. Conf., March 2019.
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
-
Acknowledgment
This research was supported by the U.S. Office of Naval Research under award numbers N00014-18-1-2156, N00014-18-1-2601, and N00014-18-1-2260.
55
Distribution A. Approved for public release, distribution is unlimited. Approved, DCN# 43-5296-19
Modeling Conducted EMI in Power Electronic SystemsContributors & CollaboratorsOutlineThe paradigm shift in power systems due to power electronics makes EMC critical to design.Present trends in power electronics likely to worsen EMI.What is electromagnetic compatibility?Some basic EMC terminologySpectra of Modern Power ElectronicsApproach to EMI challenges in PE systemsHow do you measure conducted emissions?Example: emissions from a machine-driveFields from CM current are more likely to radiate and couple with nearby equipmentThe many faces of the “Common Mode”Differential-Mode and Common-mode Equivalent circuit modelingObjectives of modeling conducted EMIModified definition for CM voltage enables rigorous & flexible model generationDM and CM definitions can be viewed generally as a space transformationThese specific definitions lay the foundation for CM equivalent circuit modeling.Why don’t we just simulate mixed-mode circuits?Example: platform developed for in situ emissions characterization of intermediary conversion systems.An example application of the modeling approachCM model development in four stepsSlide Number 23Step 1: Create the mixed-mode modelStep 2: Partition MM model around switchesStep 3: Symmetric lines transform following simple parallel addition rules in CM.Step 3(a) DetailSlide Number 28Step 3(b): three-line exampleStep 3(b) DetailStep 4: Form system model by specifying reference point(s)Step 4: Form system model by specifying reference point(s)Overall system modelHow to model effects of asymmetry?Decomposition approach to asymmetric componentsDecomposition approach to asymmetric componentsOverall system modelBonus: Analyze/approximate output CM voltage sourceBonus: Analyze/approximate mode conversion sourceSummary: CM equivalent model of the testbedApplication and validation of CM modeling approachUA SiC EMI Characterization Testbed ImplementationLeakage current through MCPM was measured in the EMI characterization testbed.Characterizing the MCPM Baseplate CapacitanceCM voltage noise source modelingEquivalent model reduced and analyzed to predict baseplate current.Study of Baseplate capacitance in multichip power modulesUnbalanced baseplate capacitance is a critical factor affecting leakage current through baseplate.Relaxed concept of CM voltage and flexible DM and CM definitions permit derivation of CM equivalent model.Analysis of leakage current through the MCPM baseplateExperimental setup was devised to validate the CM model predictions.Results of the qac sweep experimentsModel accurately predicts all significant characteristics of the BP current including ringing frequency and amplitude.Acknowledgment