Mission profile on Power Electronics Reliability

Transcription

Mission profile on Power Electronics Reliability
- importance, analysis & testing
Peter de Place Rimmen, Ke Ma, Huai Wang
Center of Reliable Power Electronics (CORPE), Aalborg University, Denmark
Danfoss Power Electronics, Denmark
pr@danfoss.com, kema@et.aau.dk, hwa@et.aau.dk
www.corpe.et.aau.dk
CORPE
Schedule of the Tutorial
■ Importance of missions profiles on reliability – industry perspective
(approx. 20-25 min)
- Overview of the involved parameters for specifying reliability.
- The role of mission profiles in product development.
- Variation in the user profiles from automotive to solar.
- Paradigm shift in reliability research in power electronics.
■ Reliability analysis based on mission profiles (approx. 25 min)
- Flows and structure for reliability analysis considering mission profiles
- Mission profiles translation and mapping under multi-time-scales
- Case study on lifetime prediction in wind power application
■ Testing of power electronic components and design for parameter
variations (approx. 25 min)
- Thermal cycling and power cycling testing of IGBT modules
- Degradation testing of film capacitors under humidity conditions
- Design for parameter variations of IGBT modules in Photovoltaic inverters
CENTER OF RELIABLE POWER ELECTRONICS, AALBORG UNIVERSITY | 0 7 . 1 0 . 2 0 1 5 | S L I D E
2
Part 1
Importance of missions profiles on reliability –
industry perspective
Peter de Place Rimmen




Overview of the involved parameters for specifying reliability.
The role of mission profiles in product development.
Variation in the user profiles from automotive to solar.
Paradigm shift in reliability research in power electronics.
3
Mission profiles
Why Mission Profile is important!
4 | Reliability Engineering 07/10/2015
Tutorial ESREF 2015
Source:
SAE, J1879 Robustness Validation Standard
ZVEI, Handbook for Robustness Validation of
Automotive Electrical/electronic Modules
The Mission Profile is a representation of all
all relevant
relevant
conditions a product will be exposed to in all
all of
of its
its
conditions
intendedapplications
applications throughout its entire
entirelife
lifecycle.
cycle
intended
Design for Robustness and Lifetime Customer Wishes [CRS]
Product-Performance
Specification [PRS] Link
Application
Mission Profile [PRS] Link
Q Customer & Brand
Safety
Quality Target [PRS] Link
Next
Existing knowledge /
Design for Reliability
“Tool box” Link
Design for Robustness and Life
Integrated Product Development
Design for Safety will in the
future consider degradation
“End of Life Risk”.
Weakness
Ref: Larry Edson
Validations for Standards
Approval / Safety Demands
Risk evaluations:
Robustness, lifetime & degradation has impact on Safety
Quality monitoring & Risk mining in project
Tutorial ESREF 2015
Link
Link
Integrated Product Development Process
shall secure the designed functions are unaffected to the environment and
user-profile in the whole expected lifetime.
Together with the Mechanicaland Electronics-Designers
Reliability Eng. makes guidelines
for how to implement needed
immunity to secure sufficient
Robustness and Lifetime.
Weakness
Analysis Phase
• What technology fit to the PRS
•
•
•
•
•
(Product Requirement Specification)?
Ref: Larry Edson
What’s new in the Requirements?
Lesson learned from previous product
Establish the knowledge to achieve targets
Establish design budgets
High level simulation on system
Development Phase [Qualitative test]
• Simulate or test for robustness at degraded Validation Phase [Quantitative test]
components to the Mission profiles.
• Accelerated lifetime test
• Highly Accelerated Limit Testing (HALT)
• 3th part approval test
philosophy used.
• Calibrated Accelerates Life Test (CALT)
Other related activities:
• Detailed simulations on
• Logistics PPAP closed (Production Part Approval Process)
functions/subsystems/system
• Produce ability proved
Tutorial ESREF 2015
Customer Wishes [*CRS]
Product-Performance Specification [PRS]
Such parameter will describe what kind of
functions the product can do examples like:
• Km/Liter
• Interfaces
• Speed
• In-/Out-puts
• Efficiency
• Resolution
• Noise level
• Storage
• Voltage in or output
• Control functions
• Frequencies
• Friction
• Load
• Power
• Capacity
•
• Sensitivity
•
• Color
•
• Surface
*CRS = Customer Requirement Specification.
Tutorial ESREF 2015
Application
Mission Profile [*PRS]
Such parameter will describe the stresses
the product/component will experience from
production, operation to end of life
examples like:
Environmental:
User profiles:
• Temperature Max/Min
• On/Off periods
• Thermal stress
• Load profiles
• Vibration
• Relocations
• Shock/Bump
• Grid used
• Humidity
• Load used
• Chemicals
• Stop and go
• Sun
• Maintenance
• Lightning
• Hot plug
• EMC/Spikes
• Altitude
*PRS = Product Requirement Specification.
Tutorial ESREF 2015
Q Customer & Brand
Quality Target [*PRS]
Such parameter will describe the availability
with confidence for the product during the
whole life as overall targets like:
Product:
• First pass yield
Q Product Target
breakdown to
Availability at:
• Functions
• Delivery
• Modules
• Warranty 2 - ? years • Components
• Lifetime ? – 20 years
• Safety
The operational way will in many
cases be focusing on why the
product is outside specification
and failing to operate!
*PRS = Product Requirement Specification.
Tutorial ESREF 2015
Explain “end of life” performance target on
Robustness and Life focus
Examples:
Component
Robustness
to
Lifetime iaw
Degradation budget
Fan with focus on
performance
capacity.
Failure criteria
defined.
Variation to:
• power
• Temperature
• Humidity
• Dirt
• Vibration
• ice
2000 meters above sea level
25% degradation of heat sink
surface
30% degradation of fans
Electronics, bearing,
Gaskets with
focus on
tightness.
Failure criteria
defined.
Can it be
mounted
without being
damaged?
Robust to:
• Chemicals
• Tools
• Handlings
Sufficient tight at end of life.
• Flexibility /stiffness
• Pressure to surfaces
• Water tight iaw specification
Electrolyte
Capacitor with
focus on:
• capacity
• ESR
• leakage current
Failure criteria
defined.
Component or
circuit are
Robust to:
• Initial Volt
• I leak
variation
• Temperature
• Shock &
Vibration
Based on vendor specs and
variation we will simulate when
failure criteria are reached for
the component or circuit.
Tutorial ESREF 2015
Validate Robustness to interaction in life time
Interaction focus
Such validations test shall prove that the
product are able to survive the specified
lifetime in the specified different
environments.
“More than 10 units are going through the
same test-legs without failing in accelerated
test. This is called Quantitative tests”.
In the shown example 36 units used in 6
different test-sequence.
Such test will be important in the future to
make sure that the customer not will be the
first to see unexpected failure mechanism.
Ref: Larry Edson
Tutorial ESREF 2015
Existing knowledge / Design for Reliability
“The Tool box”
The Tool box consist
of a lot of different
tools.
Tool boxes
•
Reactive tools.
• Field analysis (*MCF)
• Root Course Analysis
Source: Reliasoft.
Proactive tools
• Kinematics
• Simulation
• Derating
• FMEA
• DoE (Design of Experience)
• Gauge R&R / MSA
• Target setting (*MCF-model)
• Budgeting
Design For Six Sigma is a basis for Design for Reliability but do not in itself guarantee
compliance to reliability targets.
*MCF = Mean Cumulative Function
Tutorial ESREF 2015
Design for Reliability
approach
Customer
Requirements
Specification
Customer
Requirements
Specification
”Performance
shall be
specified as
end of
lifetime”
Product
“Design”
Requirements
Specification
The Rimmen model
Tutorial ESREF 2015
Design for Reliability approach
Identifying The Severe User (GM‐term)
Some applications
have small load
variations (PR)

Usage of a product varies because people or environments vary

Some people/environments will be “easy” on the product, and some will be “hard” on the product

We statistically quantify the severe user by statistically extrapolating the usage pattern from a sample of people

Six to twenty “users” are monitored for a period of time and then extrapolated out to “one life”. A Weibull analysis is performed on the points
of intersection at “one life.”
Derived
Requirement
(typically 99.8%)
Sampling period
Time
Tutorial ESREF 2015
One Design Life
Extrapolation To
One Life
10 Yrs.
Most Severe User
Observed In Our
Small Sample
Larry G. Edson / GM / 2006
Number Of
Times A
Product Is
Used Or
The Level
Of Force
Applied
“Severe User”
Design for Reliability Mission Profile
Stress
Italian
Example for small variation:
• Solar/Turbine
• Site, Same location
• Optimized
• All severe users
• Continued monitoring
Density
Density
Example for big variation:
• Car drivers/customers
• Young/old (Users)
• New/practiced
• Alone/together
• Stressed/relaxed
• Busy/Sunday
Strength
North Sea
Sweden
Tutorial ESREF 2015
Stress
Strength
Mid. Europe
The Rimmen model
Performance
Customer
Requirement
Specification
Product
“Design”
Requirements
Specification
Tutorial ESREF 2015
The Rimmen model
Performance
Customer
Requirement
Specification
Product
“Design”
Requirements
Specification
This is the areas which can be used for
Accelerated Reliability Validating Testing
Tutorial ESREF 2015
Development Phase [Qualitative test]
Failure intensity: h(t)/year
The “Bath tube curve” is:
F
I
T
F
I
T
F
I
T
F
I
T
F
I
T
Product age in service [years] Linear scale)
If FIT is the speed of failures, then all the FIT’s values are correct.
But what does it tell you?
Tutorial ESREF 2015
The “Bath tube curve” is:

Intuitively good

FIT-values from supplier are usually an result from
quantitative tests. (No failure observed)

You can use the models to calculate a failure level,
but is the result realistic?

Automotive can produce component with a failure free
period. It does not fit to FIT.

Handbooks do not reflect the component quality we
see today.

Handbooks are based on field failures and in many time
not root course analysed

Handbooks cannot be up to date with the newest
technology

The components might be much much better than
described in the handbooks.

Risk information/indicator

Physics of Failures are not considered

“FIT” does not support Robust Design

FIT or MTBF says nothing of the components
limitations (Robustness or Lifetime) only that there
were no failure found during the test conditions.

FIT is not an “excuse” for the failures
Tutorial ESREF 2015
F
I
T
F
I
T
F
I
T
F
I
T
You should ask your
component
manufacture for the
expected lifetime
(η, β & Confidence) under
the stresses (Mission
Profile) as the
component will be
exposed to
Failure intensity: h(t)/year [%]
Failed product = f(Warranty Period) [Statically without replacement]
Failure intensity [h(t)/year] "not very useful"
Tutorial ESREF 2015
Which kind of failures do you not want?
From “Bath tub” (Failure intensity curve)
Failure intensity: h(t)/year [%]
Failure intensity [h(t)/year] "not very useful"
Tutorial ESREF 2015
From “Bath tub” (Failure intensity curve)
via integration to
Mean Cumulative Functions [%]
Lack of Customer Satisfaction
Goal: “Failure Free Period”
Tutorial ESREF 2015
We must work for a “failure free period”
We must control the degradation, the wear out.
Lack of Installation‐ & Transport‐robustness [0‐Time failure level]
Some of the tools that
influence
“Dead on Arrival”:
• Design for transport
• Design for installation
• Instructions etc.
Tutorial ESREF 2015
Dead on Arrival or Zero times failures:
Some of the tools and parameters that
influence
Process & Component Failures:
Lack of Production Capabilities [Early failures]
• Design For Manufacturing
• Capability
(Six Sigma-philosophy)
• Statistic Process Control
• Tolerance Chain Analysis (statistic)
• Contaminants
• Poka Yoke
• Taguchi / DoE
• Etc.
Tutorial ESREF 2015
Early failures due to low Cpk or Cpp
in the whole supply chain
Some of the Lack of Installation‐ & Transport‐robustness [0‐Time failure level]
tools and parameters
that influence Robustness:
Lack of design robustness [statistically constant]
• Load/Strength, Derating & Margin
• Robustness Lack of Production Capabilities [Early failures]
• Thermal design
• Design Maturity
• DFMEA
• Reviews
• Six Sigma
• Etc.
Tutorial ESREF 2015
Lack of design Robustness against
“hard” and unforeseen load.
Lack of Lifetime [wear out]
Tutorial ESREF 2015
Lack of design Lifetime.
Degradations and wear out.
Failed product = f(Warranty Period) [
Statically without replacement]
Some of the tools and
parameters
that influence the designed
lifetime:
• Thermal stress
• Thermal design
• Corrosion
Lack of Lifetime [wear out]
• Load/Strength, De-rating & Margin
• DFMEA
• Six Sigma
• Robustness
• Etc.
Goal: “Failure Free Period”
One Design Life
Tutorial ESREF 2015
Lack of design Lifetime.
Degradations and wear out.
Early
failures
Lack of Robustness failures
Wear out
[lin]
M(t)
• Noise
• Overload
• …
Lifetime
Tutorial ESREF 2015
[lin]
Mission profiles – Outdoor environment
Climatic data has been downloaded
from 560 weather stations in
Europe.
Data is analysed and provides input
to design specification.
STN
====
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
EBAW
Similar data is available from
specific locations in US and Asia.
Station code Place
EBAW
EBAW Antwerp/Deurne
TIME
TMP DEW
DD/HHMM
C
C
=======
=== ===
01-01-2008 00:20
4
3
01-01-2008 01:20
3
3
01-01-2008 02:20
4
3
01-01-2008 03:20
4
3
01-01-2008 04:20
4
3
01-01-2008 05:20
5
4
01-01-2008 06:20
4
4
01-01-2008 07:20
4
3
01-01-2008 08:20
4
4
01-01-2008 09:20
4
4
01-01-2008 10:20
5
4
01-01-2008 11:20
5
3
01-01-2008 12:20
5
3
01-01-2008 13:20
5
3
Arrhenius
Average Average
Accumulated temp Total humidity Coffin-Manson Total Hours Max
Min
temp
temp Max
MIN
Average humidity Average
Total operating hours Hours
hours
Parameter
Hum dew
temp temp 2008
2009
humidity humidity 2008
humidity 2009
17.543,5
5.697,7
49.747,1
40.598,0
876,6
33,0 -14,0
11,1
11,3
100,0
21,0
77,5
75,7
RH Total Acum
%
#### ####
=== hourstemp
93
1
1
100
1 0,1
93
1 0,1
93
1 0,1
93
1 0,1
93
1 0,1
100
1 0,1
93
1 0,1
100
1 0,1
100
1 0,1
93
1 0,1
87
1 0,1
87
1 0,1
87
1 0,1
NPL=
Dark Green
Contry
Belgium
Delta t
stress pr
day
7,452463
EBBE
EBBE Beauvechain
17.544,0
5.501,2
49.964,3
31.982,5
4,3
34,0
-14,0
10,7
10,8
100,0
25,0
78,4
76,6 Belgium
EBBL
EBBL Kleine-Brogel
17.543,5
5.620,2
52.105,7
64.860,5
380,1
37,0
-19,0
10,4
11,3
100,0
19,0
79,7
78,7 Belgium
9,419712
EBBR
EBBR Brussels National
17.543,5
5.431,6
49.751,6
38.676,5
804,2
34,0
-14,0
10,6
10,9
100,0
24,0
77,5
76,5 Belgium
7,273963
6,614508
EBCI
EBCI Charleroi/Gosselies
17.543,5
5.261,9
49.707,7
36.224,5
571,6
34,0
-15,0
10,2
10,6
100,0
19,0
79,0
75,8 Belgium
7,039612
EBCV
EBCV Chievres Ab
17.543,0
5.272,2
57.181,1
32.701,5
0,0
32,0
-14,0
10,4
8,6
100,0
23,0
79,5
82,4 Belgium
6,688635
7,209031
EBDT
EBDT Schaffen
17.543,0
5.637,0
49.990,1
37.988,0
0,0
36,0
-14,0
10,8
11,1
100,0
11,0
77,7
76,5 Belgium
EBFN
EBFN Koksijde
17.542,5
5.229,0
54.914,6
33.688,0
317,8
32,0
-10,0
10,5
11,4
100,0
28,0
79,2
81,0 Belgium
6,78887
EBFS
EBFS Florennes
17.543,5
4.932,0
51.889,8
31.434,5
176,9
33,0
-14,0
9,5
10,5
100,0
17,0
80,2
79,5 Belgium
6,557688
7,991307
EBLB
EBLB Elsenborn
17.523,0
4.060,4
51.463,4
46.626,5
0,0
30,0
-21,0
7,3
7,6
100,0
12,0
83,5
84,0 Belgium
EBLG
EBLG Bierset/Liege
17.543,5
5.366,6
49.261,4
31.681,0
467,1
34,0
-15,0
10,3
10,8
100,0
22,0
78,2
75,5 Belgium
6,58335
EBOS
EBOS Oostende
17.543,5
5.067,1
53.345,5
32.160,5
1.220,9
31,0
-10,0
10,4
10,4
100,0
17,0
79,7
79,2 Belgium
6,632983
EDAH
EDAH Heringsdorf
10.185,0
2.709,4
26.921,2
8.104,5
60,5
29,0
-13,0
11,3
4,7
100,0
25,0
74,9
91,9 Germany
4,370068
Ref. Peter de Place Rimmen patent: Monitoring device usage and stress EP 2631598 A1
and
Ref. EPE 2015 ECCE :S. K. Chaudhary, P. Ghimire, F. Blaabjerg, P. B. Thøgersen, P. de P. Rimmen
Development of Field Data Logger for Recording Mission Profile of Power Converters
Tutorial ESREF 2015
Temperature
Temperature
Temperature / RH
Measured Parameters
time
time
Arrhenius Parameter:
measure of
Accumulated Temperature
Stress
Coffin-Manson Parameter:
Measure of
Plastic strain based
thermal fatigue.
time
Extreme Temperatures (&
humidity): Max. & min.
temperature (&
humidity)values in the
specified periodic intervals
are recorded.
1
1
2
2
Every 10°C rise in temperature
(above the 25° C reference)
halves the device life-time.
Tutorial ESREF 2015
RH parameter: Measure of Accumulated
weighted humidity hours.
0
if
% 50%
50
1
10
if
%
50%
Environmental data needed for
outdoor products.
Examples:
•Highest temperature
•Lowest temperature
•Highest thermal stress
•Lowest thermal stress
•Lowest RH
•Highest RH
•Lightning
•Storms
•Snow
•Rain
•Salt
•Other Chemical
•Cleaning the product
•etc
The product must be robust
against all relevant stressors
and possible combinations!
Tutorial ESREF 2015
Backup slides
Reliability Eng. interact with project & organization
Product Performance
Project and Line
Managements
Reliability Eng. task
Designers task
Understand the end of
life performance
specification target.
Help establish
performance
specification at end of
life.
Define and accept end of
life performance
specifications:
PRS defined and
accepted
Assist how to design
Performance to end of
life time
Design to specified
Performance at end of
life time
Assist how to design with Design with sufficient
margin and confidence
margin and confidence
Specify Validation
Specify and Executing
process criteria's to meet functional setup
end of life performance
specification
Tutorial ESREF 2015
Mission profile
Project and Line
Managements
Designers task
Align & accept
Assist Mission Profiles
Define and own Mission
Profiles
Explain the statistics and
the understanding of
accumulated stress in
the mission profiles
Gathering data from
applications
Assist translating
component stress and
how to avoid component
breakdowns before the
life time budget allow
this.
Translate from product to
component mission
profiles
Part of PRS
Gathering data from
applications
Tutorial ESREF 2015
Robustness and Lifetime Goals
Project and Line
Managements
Designers task
Align & accept
Define Reliability Goals
Part of PRS
Breakdown in budgets to
estimate availability and track
lifetime
Part of budget
breakdown and
estimate lifetime
Functions levels
Define functions
Design function
Assist f Robustness level
Design f Robustness
Components level
Special component are known
for low Technology Strength
Focus on design
components
Part of Project
Business Case
Calculate Warranty Cost
Assist in Cost optimization
Optimize design
Align & accept
Confidence in achieving the Qlevel
Tutorial ESREF 2015
Part 2
Reliability analysis based on mission profiles
Ke Ma
 Flows and structure for reliability analysis
 Mission profiles translation and mapping under multi-time-scales
 Case study on lifetime prediction in wind power application
36
Enabling Part of “Design for Reliability”
Typical development cycle of power electronics products
Specified
lifetime
Mission
Specifications
Design
& Development
Production
Market
×
Unexpected
Failures
High cost !
$$$
Products development considering “Design for reliability”
Specified
lifetime
Mission
Specifications
Design
& Development
Production
×
Expected
Failures
+
Reliability
Specifications
Market
+
-
$
Much lower cost !
Reliability
Evaluation Tools
37
Concept of the reliability prediction
Cost
Operation improvement
“Reliability Metrics”
Mission
Profiles
Reliability Tools
?
1.1 kVDC
IGBT
Generator
Filter
Wind turbine
2L converter
Converter
Designs
690 Vrms
Grid
· reliability
· lifecycle
· margin
· weakness
· cost
· wear-out
· ……
2L converter
Design improvement
Quality
► Mission-profile dependent
► Physics-of-failure based
► Applications compatible
38
Road Map to Access Reliability Metrics
Identification
· Critical components
· Failure mehanisms
· Major stress & strength
Critical components in Power electronics
Stress Analysis
Strength Modeling
· Mission profile translation
· Multi-physics stress
· Multi-time scales stress
· Component-based
· Accelerated/Limit test
· Degradation model
Translate mission profile to device loading
Frequency of occurance
Accelerated test of IGBT
Reliability Mapping
Stress
variation
· Stress organization
· Variation & statistics
· Multi-components system
Strength
variation
Failures !
Designed
Stress
Designed
Strength
Relation of stress, strength, failures
Rain flow counting of thermal cycles
Reliability Metrics
Indirect
· Thermal loading
· Voltage/current stress
· Stress margin
Direct
· Bx lifetime
· Robustness
· Reliability/unreliability
Thermal loading of IGBT chips
Reliability/unreliability vs. time
39
Mission Profiles of Wind Power Converter
Voltage(%)
100
Germany
90
Spain
Denmark
75
US
25
Limited space
Keep connected
above the curves
Time (ms)
0
150
500
Generator side
Wind speed (m/s)
1000
1500
Grid faults
Harsh environment
Vw
750
P
P
Q
Q
Wind Power
Conversion
System
Grid side
P/Prated (p.u.)
1.0
Underexcited
Boundary
0.8
Overexcited
Boundary
0.6
Ambient Temp. (ºC)
0.4
Ta
0.2
Time (hour)
All have impacts to thermal
cycling and reliability !
Q/Prated (p.u.)
-0.3
Underexcited
Overexcited
0.4
Q support
Variable wind and temp.
40
Main Disturbances for Thermal Cycles
Time scale
day
hour
min
sec
ms
µs
Temp. / Wind
Enviromental
Wind
Turbine
Generator
Mechanical
Electrical
Control
Grid
Switching
Main disturber
Ambient temperature, Wind variation,
Wind speed variation
MPPT
Control,
Grid
Device
switching
► Wide spread of time scales !
► Hard to model and predict.
41
Concept of Multi-Time Scales converter Modelling
Enviroment level (day-year)
·
·
·
·
Converter
System
Enviromental variance
Steady state
Analytical model
No thermal dynamics
Converter environment
MPPT
Control
System level (s-h)
·
·
·
·
Mechanical variance
Control dynamics
Ts averaged model
Slow thermal dynamics
Inverter
Control
LCL Filter
dinverter
Wind
Mechanics
Grid
+
-
+
-
Zg
Control and mechanics
1.1 kVDC
Circuit level (ms - s)
IGBT
Generator
·
·
·
·
Electrical variance
Switching dynamics
Detail circuit model
Fast thermal dynamics
690 Vrms
Filter
Wind turbine
2L converter
Grid
2L converter
Circuit and control
42
General Structure for Thermal Analysis of PE System
vdc
DC link
vabc iabc
Control
PWM
► Mismatched time constants.
Filter
► Thermal modelling instead of monitoring.
Grid
idc
► Multi-domains models need to be accurate.
Zg
► Multi-disturbances related to mission
profiles.
Typical grid-connected converter system
Idc
Q*
Electr.
param.
Duty
ratio
Vdc*
Control
Tambient
Converter
feedback
Control & Electrical models
pLoss
Loss
Thermal
impedance
ΔT
+
+
Device
Temp.
feedback
Loss & Thermal models
Signal flow for the thermal information of device
43
Circuit Level Thermal Modelling
Controls (switching cycle averaged)
vdc
Vdc*
vdc*
-
ed
id
-
+
iin
idq
dq
abc
Cdc
id*
ωLF
dq
abc
-ωLF
Q*
vdc
+
PI
PI
Q*
2
Ed
3
i q*
► Suitable for control and switching
dynamics.
► Device switching is included
► Heat sink dynamics is not included
► Thermal information from µs to a few
seconds.
Electrical behaviors (switching dynamics)
θ
vabc*
Grid
iabc
Lf
PWM
Eabc
+
PI
Converter
-
iq
PLL
abc
dq
θ
edq
eq
Pin
Electrical & control
Tj
TA
IGBT module
Thermal model (device dynamics)
Loss model (instanenous)
dabc
TC
Tj
dabc
pcon@Tj
R jc1
jc1
s
1
...
iabc
pdevice
...
+
+
R jcn
jcn
s
∑
ΔTjc
Tj
+
1
Moudule
psw@Tj
Case temperature
vdc
fs
Tj
Tc
Loss & thermal
200 ms, 1 µs step
44
System Level Thermal Modelling
Controls (switching cycle averaged)
Electrical behaviors (switching cycle averaged)
ed
vdc
Vdc*
vdc*
-
ed
id
-
+
PI
PI
ed
PWM
+
id*
2
Ed
3
i q*
PI
-
id
1
s LF
+
×
RF
dd
-ωLF
+
÷
PWM
×
dq
+
iq
-
+
1
s Cdc
icap
vdc
×
RF
eq
eq
3/2
dq
1
s LF
-
+
+
ωLF
vdc
-
iq
×
iin
id
vdc
-ωLF
Q*
dd
÷
ωLF
Q*
iin
► Suitable for control and mechanical
dynamics
► Device switching is not included
► Heat sink dynamics is included
► Thermal information above switching
cycle to hours.
Pin
iq
Tj
TA
eq
IGBT module
Foster Model (Gain from Pin to Tjc)
Pout other devices
TC
LPF
Pout
Rch
Thermal
Grease
Heat sink
Ch
Gain from Pin to Pout
Thermal model (device + heat sink dynamics)
Loss model (switching cycle averaged)
dabc
dabc
jc1
pcon@TH
Conduction
loss function
pcon@TL
Temp.
depedent
function
iabc
pcon@Tj
pdevice1
jcn
s
iabc
psw@TL
psw@Tj
pdevice2
+
Thermal grease
∑
…
…
fs
LPF
ΔTch
Rch
Gpin_to_pout
pdeviceN
vdc
Tj1
1
LPF
psw@TH
Temp.
depedent
function
+
Moudule
+
Switching
loss function
ΔTjc
∑
R jcn
+
Esw@TH
Esw@TL
1
...
Vcon@TL
s
...
Vcon@TH
idq
R jc1
Tj
ha
Rha
s 1
+
Tc1
Th
Heat sink
Ta
Tj
Loss & thermal
3 hours, 1 second step
45
Environment Level Thermal Modelling
Electrical behaviors (steady state)
iin
ed
► Suitable for environmental dynamics
► Control and electrical part is
considered as steady state.
► Thermal information above
fundamental cycle to years.
eq
Controls (steady state)
Vdc*
id
vdc
vdc*
RF id
RF iq
Q*
Q*
iq
2
Ed
3
iin
LF iq
vdc d d
LF id
1.5 (id d d
ed
vdc d q
dd
eq
iq d q )
dq
Pin
Tj
TA
IGBT module
Pout other devices
TC
Rch
Thermal
Grease
Thermal model (heat sink/No dynamics)
Loss model (fundemental cycle averaged)
dabc
Tj
M
Pcon@TH
Conduction
loss function
Pcon@TL
Temp.
depedent
function
idq
Pcon@Tj
Pdevice1
Temp.
depedent
function
Psw@Tj
∑
Pdevice2
…
…
fs
+
Thermal grease
PdeviceN
vdc
ΔTch
Rch
Psw@TH
Psw@TL
Tj1
Rjcn
+
Switching
loss function
+
Moudule
+
Imax
ΔTjc
∑
...
φ
Ch
Rjc1
...
Imax
Heat sink
Tj
ha
Rha
s 1
+
Tc1
Th
Heat sink
Ta
Loss & thermal
1 year, 5 mins step
46
Incompatibility of Thermal Stress and Lifetime Model
Temperature
ΔT
Tm
time
Thermal stress with constant ΔT and Tm
Typical lifetime model
Only constant ΔT and Tm can be mapped
to cycles to failure in this figure !
Thermal stress in real world - Variable ΔT and Tm
47
Stress Organization by Rainflow Counting Method
Source: M. Matsuishi, T. Endo, “Fatigue of metals subjected to varying stress”, Japan Soc. Mech. Engineering, 1968.
Thermal stress vs. time
Typical lifetime model
Rainflow counting
Cycle number vs. ΔT and Tm
ΔT and Tm at each cycle
48
Miner Rules and Accumulated Damage
Stress level
1
Stress level
K
Stress
Stress level
2
N1
Miner rules:
N2
…
Stress level
K-1
NK-1
NK
N1
N
N
 2  ...  K  1
N F1 N F 2
N FK
Nk – number of counted cycles at stress level k;
NFk – number of cycles to failure at stress level k – acquired from life time model;
Accumulated damage: ADn 
N
N1
N
 2  ...  n
N F1 N F 2
N Fn
(for 1  n  K )
Dn: Accumulated damage caused by N1+N2+…Nn counted cycles
49
An Example from Wind Speeds to B10 Lifetime
Source: K. Ma, M. Liserre, F. Blaabjerg, T. Kerekes, “Thermal Loading and Lifetime Estimation for Power Device Considering Mission
Profiles in Wind Power Converter,” IEEE Trans. on Power Electronics, 2014.
IGBT
Generator
690 Vrms
Filter
Wind turbine
2L converter
Consumed B10 life time / year (%)
1.1 kVDC
Grid
2L converter
Converter design
(Loss curve)
Loading
Translation
Po(t)
Loss
Ploss
Calculation
Thermal analysis
Thermal
Rainflow
Impedance
Count
N
Lifetime
Mapping
Reliability
Metrics
Reliability mapping
Consumed B10 lifetime (%)
Mission profile
(solar, wind, grid)
Converter design
(Cooling and device)
Wind speed (m/s)
50
A Matlab Tool for Lifetime Evaluation
Key features
► User specified mission profiles inputs
► Wind power, solar PV and motor drive applications
► Outputs: accumulated damage as function of time, B10 lifetime
51
Examples by using the tools – mission profiles
1 year Wind speed recorded at Thyboron wind farm
Damage built in 1 year
A typical ClassIA wind speed variation in 60 hours
Damage built in 60 hours
52
Examples by using the tools – cooling strategy
Cooling behavior of heat sink during the shut down of wind turbines
Reduce to ambient temperature.
Maintain to constant temperature.
53
Critical issues of reliability prediction
Identification
· Critical components
· Failure mehanisms
· Major stress & strength
► Accurate but fast-simulated thermal model
Stress Analysis
Strength Modeling
· Mission profile translation
· Multi-physics stress
· Multi-time scales stress
· Component-based
· Accelerated/Limit test
· Degradation model
► Correct mission profiles in the real filed operation.
► Variation of parameter/stress/strength in
components
► Impacts of multi-components and redundancy
design
Reliability Mapping
· Stress organization
· Variation & statistics
· Multi-components system
► Other failure mechanisms and components
► Validating the prediction results
Reliability Metrics
Indirect
· Thermal loading
· Voltage/current stress
· Stress margin
Direct
· Bx lifetime
· Robustness
· Reliability/unreliability
54
More Advanced Thermal Modelling – FEM Simulation
Structure modeling of IGBT module mounted on water
cooling system
Structure modelling of cooling system
► Suitable for thermal distribution analysis
► Only for very short term or steady-state
► Thermal information below a few seconds
Thermal distribution inside module
55
From FEM to Circuit Simulation – Extended Time Ranges
Ploss ( diode )
Temperature
monitoring points
T
detail distribution
P [W]
Step Ploss (IGBT)
Trial1: to IGBT chip
P [W]
Step Ploss (diode)
t [s]
i9
i8
i7
i6
i5
i4
i3
i2
i1
d3 d2 d1
Trial2: to diode chip
d6 d5 d4
T d9
d8 j
T
d7 j
j
T
d6
T
d5 j
d2
d1 j
d4 j
j
j
T
T
T
Diode Chip
T jd 3
)
)
Z th( d( 2j coupl
Z th(i(j2coupl
s1)
s1)
Z thd (2 j  s1)
Tsd1 9
Tsd1 8
Temp [°C]
Tsd1 7
T d3
T d6
d 5 s2
Tj Ts1
Ts2
Z thi 2( j  s1)
i2
s1
i8
s1
T
T
Tsi19
Tsi17
Tsi14
IGBT Chip Solder
i2
Tsi21
)
)
Z th(i(2s1coupl
Z th( d(s22coupl
 s 2)
c)
Z thd (2s 2c )
Tsi16
i5
s1
Ploss ( diode ) Z th ( s1 s 2)
Ploss ( IGBT )
T d3
d 2 s2
Baseplate Solder
Tsi13
T
Tsi11
Ts 2
Tsd28 Ts 2
Tsd27 Tsd1 4
Tsd21
critical layers
IGBT Chip
)
)
Z th( d(s12coupl
Z th(i(2s1coupl
s 2)
 s 2)
Z thd (2s1 s 2)
Tsd29
Ploss ( diode )
d 2 s1
d 1 s1
Tsd1 5 T
Ts1
Tsd1 4
t [s]
t [s]
Ploss ( IGBT )
Diode Chip Solder
Temperature
responses
d9 d8 d7
Tsd1 6
T ji1
Ploss ( IGBT )
T ji 9
T ji 3 T ji 6
i2
i5
i8
Tj
Tj
Tj
T ji 7
T ji 4
Ploss ( diode )
Ploss ( IGBT )
i2
s2
T
Tsi23
Tsi24
i5
s2
T
Tsi26
Tsi27
i8
s2
T
Tsi29
Baseplate Solder
Z thi 2( s 2c )
Tc
Z th ( c  a )
Temperature responses at critical points
(Extraction of thermal impedance curves)
Ta
3D thermal network based on FEM
simulation
► Only critical points and layers are focused
► Thermal coupling & boundary conditions are considered and modeled.
► New 3-dimensional thermal impedance geometry
56
Results Comparison Between FEM and 3D Thermal
Impedance
i2_s1
i5_s1
i8_s1
i2_s2
i5_s2
i8_s2
D2
Tj
T1
Tji2 Tji1
D1
T2
(FEM simulation, 15 min by
work station)
i3
Temperature measured by infrared
camera
(Extracted thermal network,
15 sec by laptop)
97
Model
FEM
Experiment
96
95
► Much fast simulation speed - enable
longer term stress analysis and
integration with other models
94
Temperature (C)
► Thermal cycling information are
accurately remained in critical points.
93
92
91
90
89
88
87
0
0.2
0.4
0.6
0.8
Time (s)
1
1.2
1.4
Temperature comparison on i2 point
57
1.6
Part 3
Testing of Power Electronic Components and
Design for Parameter Variations
Huai Wang
■ Power cycling testing of IGBT modules
■ Degradation testing of film capacitors under humidity conditions
■ Design for parameter variations of IGBT modules
58
Reliability Critical Components in Power Electronics
An example of capacitors
(Photo courtesy of CDE).
An example of IGBT module
(Photo courtesy of Infineon).
Percentage of the response to the most frangible components in power electronic systems from an industry
survey (% may vary for different applications and designs)
Data sources: S. Yang, A. Bryant, P. Mawby, D. Xiang, R. Li, and P. Tavner, "An Industry-Based Survey of Reliability
in Power Electronic Converters," IEEE Transactions on Industry Applications, vol. 47, pp. 1441-1451, 2011.
59
IGBT Power Cycling Testing
TC-thermal cycling; PC-power cycling
60
LESIT Project Power Cycling Testing (1993-1995)
(LESIT
– Leistung Elektronik Systemtechnik Informations Technologie)
Figure source: U. Scheuermann and U. Hecht, “Power cycling lifetime of advanced power modules for different temperature swings,” in
Proc. PCIM Europe 2002, pp. 59-64.
Data source: M. Held, P. Jacob, G. Nicoletti, P. Scacco, M. H. Poech, “Fast power cycling test for IGBT modules in traction application,” in
Proc. Power Electronics and Drive Systems 1997, 425-430.
Number of cycles to failure as function of ΔTj with Tm (mean temperature).
Testing focus: bond wire reliability of IGBT modules in traction application
Testing samples: 300A/1200V single switch IGBT modules from different suppliers
Testing conditions: ΔTj : 30°C to 80°C, VGE: 15V, current load : 240 to 300A, ton :0.6 to 4.8s, and toff : 0.4 to 5s
Failure criterion: 5% increase of VCE
Measurement method: periodical static measurement of VCE
61
RAPSDRA Project Power/Thermal Cycling Testing
(RAPSDRA – Reliability of Advanced High Power Semiconductor Devices for Railway Traction Application)
Source: H. Berg and E. Wolfgang, "Advanced IGBT modules for railway traction applications: Reliability testing," Microelectronics Reliability
38(6-8): 1319-1323, 1998.
Proposed reliability tests in RAPSDRA project
Reliability test
Proposed testing conditions
Standards
Estimated
testing time
Testing focus
Power cycling 1
(active)
Tmin = 55°C, ΔT=50°C, 70°C
Ic = Icnom, tcycle=3 sec
Non-standard
3 million cycles
(104 days)
Bond wire reliability
Traction application
Power cycling 2
(active)
Tmin = 55°C, ΔT=50°C, 70°C
Ic = Icnom, tcycle=1 min
Non-standard
100 k cycles
(70 days)
Solder reliability
Thermal cycling
(passive)
Tmin = 25°C, Tmax = 105°C, 125°C,
tcycle=4 min
Non-standard
10 k cycles
(28 days)
Solder reliability
RAPSDRA project extends the testing focus to the solder joint reliability
62
PWM Switching Based Power Cycling Testing
Source: V. Smet, V., F. Forest, et al., "Ageing and failure modes of IGBT modules in high-temperature power cycling,"
IEEE Transactions on Industrial Electronics, 58(10): 4931-4941.
DC pulse
PWM pulse
More realistic testing (i.e. switching, high voltage, dynamic loss) under PWM switching conditions
Testing with inverter legs in a back-to-back configuration
600V/200A IGBT modules for automobile traction application
63
Power Cycling Testing at Aalborg University
For wind power converter applications
64
PWM switching currents with online on-state voltage monitoring
Source: Pramod Ghimire, Stig Munk-Nielsen, et. al
Testing setup
Designed gate driver with integrated on-state voltage
measurement circuits and CONCEPT driver core
■ More realistic testing (i.e. switching, high voltage, dynamic loss) under switching conditions
■ Testing with inverter legs of 1700V/1000A IGBT modules for wind power application
■ Online measurement of VCE
65
Wear Out Testing Results
Source: Pramod Ghimire, Stig Munk-Nielsen, et. al
Stressed parameter for ageing test of power module
DC link voltage
1000V
Load current
650Arms
Output frequency
6 Hz
Switching frequency
2.5kHz
Cooling temperature
80oC
Cooling
Water mixed with glycol
On-state voltage increase of the lower
side switches of the power modules
66
DC currents (10 modules simultaneously)
Source: Stig Munk-Nielsen, et. al
Specifications of the testing setup
Type of DUT
1000V
Max. No. of DUTs
10 power modules
DC currents
< 2000A
Duty cycle
ton=2s , toff=8s
(adjustable)
ΔTjunction
<150°C
Cooling water temp.
25°C - 80°C
67
PWM switching currents (for 600 V/30 A low power modules)
Source: Uimin Choi, et. al
Testing conditions: ∆Tj = 80 °C, Th = 48 °C, 30 A current RMS, 400 V DC link, cycle period = 1 s)
68
A Widely Used Lifetime Model for Capacitors
A simplified model derived from the above equation
The information of humidity impact is usually not available!
Lx – expected operating lifetime; L0 – expected lifetime for full rated voltage and temperature; Vx –
actual applied voltage; Vo – rated voltage; T0 – maximum rated ambient temperature; Tx – actual
ambient temperature; Ea is the activation energy, KB is Boltzmann’s constant (8.62×10−5 eV/K)
69
Capacitor Testing System
System configuration
■ Climatic chamber
■ 2000 V (DC) / 100 A (AC) / 50 Hz
to 1 kHz ripple current tester
■ 2000 V (DC) / 50 A (AC) / 20 kHz
to 100 kHz (discrete) ripple
current tester
■ 500 V (DC) / 30A (AC) / 100 Hz
to 1 kHz (discrete) ripple
current tester
■ LCR meter
■ IR / leakage current meter
■ Computer
System capability
■
■
■
■
Temp. range -70 °C to +180 °C
Humidity range (for a certain range of temp.): 10 % RH to 95 % RH
DC voltage stress up to 2000 V and ripple current stress up to 100 A and 100 kHz
Measurement of capacitance, ESR, inductance, insulation resistance, leakage current and hotspot temperature
70
Testing Results MPPF-Caps Capacitance (normalized)
85°C, 85%RH
2,160 hours
85°C, 70%RH
2,700 hours
Testing of 1100 V/40 μF MPPF-Caps
85°C, 55%RH
3,850 hours
(Metalized Polypropylene Film)
Sample size: 10 pcs for each group of testing
71
Testing Results Weibull Plots
85°C, 85%RH
85°C, 70%RH
Testing of 1100 V/40 μF MPPF-Caps
85°C, 55%RH
(Metalized Polypropylene Film)
Sample size: 10 pcs for each group of testing
72
Humidity-Dependent Lifetime
73
An Example of Photovoltaic (PV) Inverter
An electrical energy conditioning system to convert the
DC power from PV panels to AC power to the electric grid.
74
Translation of Mission Profile into Power
Tamb – ambient temperature; SI – Solar Irradiances; Pin – input power of the PV inverter
75
Translation Thermal Stress Profiles into Lifetime
Distribution
Source of lifetime model: R. Bayerer, T.
Hermann, T. Licht, J. Lutz, and M. Feller,
“Model for power cycling lifetime of IGBT
modules - Various factors influencing
lifetime,” in Proc. International Conference
on Integrated Power Systems (CIPS), pp.
1–6, 2008.
Tj – junction temperature; Ploss – power loss; Rth – thermal resistance; ∆Tj – junction temperature
variation; N- number of cycle to failure; Tj, min – minimum junction temperature; ton- heating time of the
power cycling; V- blocking voltage of the IGBT chips; I- current per bond wire; A, β1 to β6 are constants;
CI – Confidence Interval
76
Parameter Variations in IGBTs and the Lifetime Model
Vce,on – on-state voltage drop of IGBTs.
77
Annual Mission Profile of Solar Irradiance
and Ambient Temperature (1s/data)
78
Annual Accumulated Damage Distribution with Respect
to Each Parameter Variation
79
Predicted Lifetime Distribution of Bond-Wires of the
IGBT Module
80
References
1. H. Wang, M. Liserre, F. Blaabjerg, P. P. Rimmen, J. B. Jacobsen, T. Kvisgaard, J. Landkildehus, "Transitioning to physics-of-failure as
a reliability driver in power electronics," IEEE Journal of Emerging and Selected Topics in Power Electronics, vol. 2, no. 1, pp. 97-114,
Mar. 2014. (Open Access)
2. H. Wang, M. Liserre, and F. Blaabjerg, “Toward reliable power electronics - challenges, design tools and opportunities,” IEEE Industrial
Electronics Magazine, vol.7, no. 2, pp. 17-26, Jun. 2013.
3. H. Wang, F. Blaabjerg, and K. Ma, “Design for reliability of power electronic systems,” in Proceedings of the Annual Conference of the
IEEE Industrial Electronics Society (IECON), 2012, pp. 33-44.
4. S. Yang, A. T. Bryant, P. A. Mawby, D. Xiang, L. Ran, and P. Tavner, “An industry-based survey of reliability in power electronic
converters,” IEEE Trans. Ind. Appl., vol. 47, no. 3, pp. 1441-1451, May/Jun. 2011.
5. Y. Yang, H. Wang, F. Blaabjerg, and K. Ma, "Mission profile based multi-disciplinary analysis of power modules in single-phase
transformerless photovoltaic inverters," in Proceedings of European Conference on Power Electronics and Applications, 2013, pp. P.1P.10.
7. S. Beczkowski, P. Ghimire, A. R. de Vega, S. Munk-Nielsen, B. Rannestad, P. Thøgersen, “Online Vce measurement method for
wear-out monitoring of high power IGBT modules”, in Proc. EPE 2013, pages 1-7.
8. P. Ghimire, A. R. de Vega, S. Beczkowski, B. Rannestad, S. Munk-Nielsen, P. Thøgersen, “Improving reliability of power converter
using an online monitoring of IGBT modules”, IEEE Industrial Electronics Magazine, Vol. 8, No. 3, 09.2014, p. 40-50.
9. Ghimire, Pramod; Pedersen, Kristian Bonderup; de Vega, Angel Ruiz; Rannestad, Bjørn; Munk-Nielsen, Stig; Thøgersen, Paul Bach, “
A real time measurement of junction temperature variation in high power IGBT modules for wind power converter application”,
Integrated Power Systems (CIPS), 2014 8th International Conference on. VDE Verlag GMBH, 2014. p. 1-6 6776812.
10. Ghimire, Pramod; Pedersen, Kristian Bonderup; Rannestad, Bjørn; Munk-Nielsen, Stig; Thøgersen, Paul; Rimmen, Peter de Place.,
”Real time wear-out monitoring test setup for high power IGBT modules”, Submitted in Transaction on Power electronics.
11. R. Bayerer, T. Hermann, T. Licht, J. Lutz, and M. Feller, “Model for power cycling lifetime of IGBT modules - Various factors influencing
lifetime,” in Proc. International Conference on Integrated Power Systems (CIPS), pp. 1–6, 2008.
12. H. Wang and F. Blaabjerg, “Reliability of capacitors for DC-link applications in power electronic converters – an overview,” IEEE
Transactions on Industry Applications, vol. 50, no. 5, pp. 3569-3578, Sep./Oct. 2014. (Open access)
13. H. Wang, D. A. Nielsen, and F. Blaabjerg, “Degradation testing and failure analysis of DC film capacitors under high humidity
conditions,” Microelectronics Reliability, in press, doi:10.1016/j.microrel.2015.06.011.
14. P. D. Reigosa, H. Wang, Y. Yang, and F. Blaabjerg, “Prediction of bond wire fatigue of IGBTs in a PV inverter under long-term
operation,” in Proc. APEC, pp. 3052-3059, 2015.
81
References
14. M. Matsuishi, T. Endo, “Fatigue of metals subjected to varying stress”, Japan Soc. Mech. Engineering, 1968.
15. K. Ma, D. Zhou, F. Blaabjerg, “Evaluation and Design Tools for the Reliability of Wind Power Converter System,” Journal of
Power Electronics, in press, 2015.
16. L. Popova, K. Ma, F. Blaabjerg, J. Pyrhonen, “Device Loading of Modular Multilevel Converter in Wind Power”, IEEJ Journal
of Industry Applications, Vol. 4, No. 4, 2015.
17. K. Ma, A. S. Bahman, S. M. Beczkowski, F. Blaabjerg, “Complete Loss and Thermal Model of Power Semiconductors
Including Device Rating Information,” IEEE Trans. on Power Electronics, Vol. 30, No. 5, pp. 2556-2569, May 2015.
18. K. Ma, M. Liserre, F. Blaabjerg, T. Kerekes, “Thermal Loading and Lifetime Estimation for Power Device Considering
Mission Profiles in Wind Power Converter,” IEEE Trans. on Power Electronics, Vol. 30, No. 2, pp. 590-602, 2015.
19. A. Sajjad, K. Ma, F. Blaabjerg, “A Novel 3D Thermal Impedance Model for High Power Modules Considering Multi-layer
Thermal Coupling and Different Heating/Cooling Conditions. “ in Proc APEC 2015.
20. K. Ma, F. Blaabjerg, “Multi-timescale Modelling for the Loading Behaviours of Power Electronics Converter” in Proc. ECCE
2015.
21. K. Ma, N. He, F. Blaabjerg, M. Andresen, M. Liserre, “Frequency-Domain Thermal Modelling of Power Semiconductor
Devices” in Proc. ECCE 2015.
82
Thank you for your attention!
Center of Reliable Power Electronics (CORPE), University, Denmark
Danfoss Power Electronics, Denmark
For presentation slides download:
www.corpe.et.aau.dk
CORPE

Mission profile on Power Electronics Reliability

Transcription

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