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Power Electronics - Key Technology for Renewable Energy Systems

Center of Reliable Power Electronics


Prof. Frede Blaabjerg

Professor, IEEE Fellow

[email protected]

Aalborg University Department of Energy Technology

Aalborg, Denmark

CORPE

www.corpe.et.aau.dk

http://www.corpe.et.aau.dk/

mailto:[email protected]

Outline

2 Center of Reliable Power Electronics

► Aalborg University, Department of Energy Technology, Denmark

► Renewable Energy in Denmark

► Power Electronics for Wind Turbines

► Power Electronics for Photovoltaics

► Challenges of Power Electronics in Renewable Energy Systems

► Conclusions

Power Electronics -

Key Technology for Renewable Energy Systems –

Status and future


Aalborg University

Department of Energy Technology,

Denmark

Aalborg University - Denmark


PBL-Aalborg Model (Project-organised and problem-

based)

Inaugurated in 1974

20,000 students

2,00 faculty

Aalborg University - Campus


Department of Energy Technology


Energy production - distribution - consumption - control

HEAT

LOADS POWER STATION

SOLAR CELLS

WIND TURBINE

MOTOR

PUMP

ROBOTICS

REFRIGERATOR

TELEVISION

LIGHT

TRANSFORMER

INDUSTRY

=

POWER SUPPLY

ac dc

TRANSFORMER

COMPEN - SATOR

FUEL CELLS

FUEL [

COMMUNICATION

COMBUSTION ENGINE

SOLAR ENERGY

TRANSPORT

3 3 3 1 - 3

3

DC

AC

~

POWER STATION

SOLAR CELLS

WIND TURBINE

MOTOR

PUMP

ROBOTICS

REFRIGERATOR

TELEVISION

LIGHT

TRANSFORMER

INDUSTRY

=

POWER SUPPLY

ac dc

TRANSFORMER

COMPEN - SATOR

FUEL CELLS

FUEL [

COMMUNICATION

COMBUSTION ENGINE

SOLAR ENERGY

TRANSPORT

3 3 3 1 - 3

3

DC

AC

~

DC

AC

DC

AC

PRIMARY

FUEL

CHP

Energy

Storages

Energy

Storages

FACTS/CUPS



Strategic Networks

• EMSD

• CEES

• ECPE

• VE-NET

• DUWET

• WEST

• VPP

• REN-DK

• HUB NORTH

• Energy Sponsor

Programme

Fluid Power and

Mechatronic

Systems

Fluid Mechanics

and Combustion

Electric Power

Systems

Power Electronic

Systems

Electrical

Machines

• 50+ VIP

• 70+ PhD

• 10+ Guest Researchers

• 10+ Research Assistants

• 22 TAP

Smart Grids and Active Networks

Wind Turbine Systems

Fluid Power in Wind and Wave Energy

Biomass

Photovoltaic Systems and Microgrids

Modern Power Transmission Systems

Fuel Cell and Battery Systems

Automotive and Industrial Drives

Efficient and Reliable Power Electronics

Thermoelectrics

Green Buildings

Multi-disciplinary Research Programmes Lab. Facilities

• Power Electronics

Systems

• Drive Systems Tests

• Fluid Power

• Power Systems & RTDS

• Micro Grid

• High Voltage

• dSPACE

• PV Converter &

Systems

• Laser Systems

• Fuel Cell Systems

• Battery Test

• EMC

• Vehicles Test Lab

• Biomass Conversion

Facilities

• Proto Type Facilities

Thermal Energy

Systems



Renewable Energy in Denmark

Energy and Power Challenge


Four main challenges in energy

Sustainable energy production (backbone, weather based, storage)

Energy efficiency

Mobility

Infrastructure

EU Set-plan (20-20-20) and beyond

Danish Climate Commision – Independent in 2050

Germany – no nuclear in the future (2022)

Globally large activity

Different initiatives

Renewable Electricity in Denmark


Key figures for proportion of renewable electricity

Key figures 2010 2011 2020 2035

Wind share of net generation in year 21.3% 29.4% 50%*

Wind share of consumption in year 22.0% 28.3%

RE share of net generation in year 32.8% 41.1% 100%*

RE share of net consumption in year 33.8% 39.0%

(Data source: Energinet.dk)

(Data source: Energinet.dk) (*target value)

2011 Renewable Electricity Generation

in Denmark

11

Energy and Power Challenge in DK

Very high coverage of distributed generation.

Bri

ef

Tech

no

logy

De

velo

pm

en

t


Development of Electric Power System in Denmark


From Central to De-central Power Generation

(Picture Source: Danish Energy Agency) (Picture Source: Danish Energy Agency)


Power Electronics for Wind Turbines

Renewable Energy System


Important issues for power converters Reliability/security of supply

Efficiency, cost, volume, protection

Control active and reactive power

Ride-through operation and monitoring

Power electronics enabling technology

Load/

Generator

Power

Electronics

Intelligent

ControlReferences

(Local/Centralized)Communication

Bi-directional Power Flow

2/3 2/3

Appliances, Industry, etc.

Renewable Energies

(PV, Wind Turbines, etc.)

Power

Grid

Wind Turbine Development


Global installed wind capacity (up to 2012): 283 GW, 2012: 45 GW

Worldwide wind power capacity

(Giga Watts)

1980 1985 1990 1995 2000 2005 2011

50 kW

D 15 m

100 kW

D 20 m

500 kW

D 40 m

600 kW

D 50 m

2 MW

D 80 m

5 MW

D 124 m

7~8 MW

D 164 m

≈ 0% 10% 30% 100%Rating:Power

Electronics

2018 (E)

10 MW

D 190 m

Soft starter Rotor resistance control

Rotor power control

Full generator power control

Role:

Higher total capacity (59 % non-hydro renewables).

Larger individual size (average 1.8 MW, up to 8 MW).

More power electronics (up to 100 % rating coverage).

Requirements for Wind Turbine Systems


Wind Power

Conversion

System

1. Controllable I

2. Variable freq & U

P

Q

P

Q

1. Energy balance/storage

2. High power density

3. Strong cooling

4. Reliable

1. Fast/long P response

2. Controllable/large Q

3. freq & U stabilization

4. Low Voltage Ride Through

Generator side Grid side

General Requirements & Specific Requirements

Grid Codes for Wind Turbines


Conventional power plants provide active and reactive power, inertia

response, synchronizing power, oscillation damping, short-circuit

capability and voltage backup during faults.

Wind turbine technology differs from conventional power plants

regarding the converter-based grid interface and asynchronous

operation

Grid code requirements today

► Active power control

► Reactive power control

► Frequency control

► Steady-state operating range

► Fault ride-through capability

Wind turbines are active power plants.

Power Grid Standards – Ride-Through Operation

18

0

25

75

90

100

150 500 750 1000 1500

Voltage(%)

Time (ms)

DenmarkSpain

Germany

US

Keep connected

above the curves

Grid voltage dips vs. withstand time

100%

Iq /Irated

Vg (p.u.)

0.5

0

Dead band

0.9 1.0

20%

Reactive current vs. Grid voltage dips

Withstand extreme grid voltage dips.

Contribute to grid recovery by injecting Iq.

Higher power controllability of converter.

Requirements during grid faults


Wind Turbine Concepts


► Wound-rotor induction generator

► Variable pitch – variable speed

► ±30% slip variation around

synchronous speed

► Power converter (back to back/

direct AC/AC) in rotor circuit

► Variable pitch – variable speed

► With/without gearbox

► Generator

Synchronous generator

Permanent magnet generator

Squirrel-cage induction generator

► Power converter

Diode rectifier + boost DC/DC + inverter

Back-to-back converter

Direct AC/AC (e.g. matrix,

cycloconverters)

20

Back-to-back two-level voltage source converter

Proven technology

Standard power devices (integrated)

Decoupling between grid and generator (compensation for

non-symmetry and other power quality issues)

Need for major energy-storage in DC-link (reduced life-time and

increased expenses)

Power losses (switching and conduction losses)

Back-to-back VSC

Power Electronic Converters

Transformer

2L-VSC

Filter Filter

2L-VSC


21

Power converters

Proven technologies today

Boost and Voltage Source Converter to grid

Power Electronic Converters

Transformer

Filter Filter

Transformer

Filter Filter

Current Source Inverter to grid


22

Multi-Level Topologies +6 MW

Transformer

3L-NPC

Filter Filter

3L-NPC

Transformer

open windings

Filter Filter

3L-HB 3L-HB

Three-level NPC

Half-bridge and open-winded transformer


23

5L-HB

Transformer

(open windings)

5L-HB

Filter Filter

3L-NPC

Transformer

(open windings)

5L-HB

Filter

Filter

Half-bridge, five-level

Three-level and five-level



24

...

Cell 1

Cell N

...

AC

DC

DC

AC

AC

DC

DC

AC

...

AC

DC

DC

AC

AC

DC

DC

AC

MFT

MFT

...

...

To grid

DC

DC

DC

AC

DC

DC

DC

AC

Rectifier

MVDC

To generator

Medium frequency transformer

Stacked output converter



Control Structure for a Wind Turbine System


Power has to be controlled by means of the aerodynamic system and has to react

based on a set-point given by a dispatched center or locally with the goal to maximize

the power production based on the available wind power.

IGen.

Fault ride through

& Grid support

Igrid

Vgrid

Vdc

Power Maximization

& Limitation

Inertia

Emulation

Power

Quality

Ancillary Services

WTS Specific Functions

Basic Control Functions

Current/Voltage

Control

Energy

Storage

Grid

Synchronization

Xf

θ

Ωgen.

DFIG

SG/PMSG

IG

I

S

D

Pmeas.,Qmeas.

AC

DC

AC

DC

Gear

Grid

FilterWind

Ambient

Temperature

Mission profilesSupervisory command

from DSO/TSO

Vdc

Control

PWMPWM

Monitoring and Control

Pin

Q

Po

Q

Communication

Current Development Example


Vestas V164 offshore turbine

Rated power: 8,000 kW

Rotor diameter: 164 m

Hub height: min. 105 m

Turbine concept: medium-speed gearbox,

variable speed, variable pitch, full-scale

power converter

Generator: permanent magnet

Vestas Wind Systems A/S Denmark

Target market: Big offshore farms

27

Vestas V80–2.0 MW

Horns Reef I 160 MW, Horns Reef II 209.3 MW • 80 x 2MW (Vestas V80, in

operation Dec 11, 2002)

• 91 x 2.3MW (Siemens SWT-2.3-93, in operation Sep 17, 2009)

Rotor Diameter 80 m Hub Height 60-100 m Weight 227-303 tons Min/Max rotation speed 9/19 rounds/minute Min/Nom/Max Wind 4/16/25 m/s Gear box Yes (1:100.5) Generator DFIG (4 pole – slip rings)

Current Development Example – Wind Farm


Improved Performance of Wind Turbines

Variable speed wind turbine integrated with a battery storage system

Center of Reliable Power Electronics 27


Power Electronics for Photovoltaics

Photovoltaic System Development


More significant total capacity (21 % non-hydro renewables).

Fast growth rate (60 % between 2007-2012).

Global installed PV capacity (up to 2012): 100 GW, 2012: 29 GW

Worldwide solar PV capacity

(Giga Watts)

Gro

wth

ra

te o

f in

sta

lled

ca

pa

city

Requirements for Photovoltaic Systems


General Requirements & Specific Requirements

Photovoltaic

Conversion

System

1. Controllable I/U

P P

Q

1. High efficiency

2. Low common mode I

3. Temp. insensitive

4. Reliable

1. Low THD

PV panel side Grid side

PV System Configurations


► High efficiency mini-central (multi-string) PV inverters (8-15 kW) are also emerging for

modular configuration in medium and high power PV systems

► Central inverters are available on market with very high power capacity (e.g. 750 kW by SMA)

► Transformerless PV inverters can achieve high efficiency with increasing popularity

AC bus

AC

DC

AC

DC

DC

DC

DC

DC

AC

DC

AC

DC

AC

DC bus

DC

PV StringsPV String

Multiple PV Strings

Module

Inverter

3 phase1 or 3 phase1 phase 1 or 3 phase

Source:

Infineon, SMA

Power Rating ~ 300 W 1 kW~10 kW 10 kW~30 kW 30 kW ~

Typical Applicaitons Small System Residential Commercial/Residential Commercial / Utility-Scale

PV Plants

String

Inverter

Multi-String

Inverter

Central

Inverter

33

PV

Arr

ays

Filt

er

LF

Transformer

PV

Arr

ays

Filt

er

HF

Transformer

PV

Arr

ays

Filt

er

*

Transformer-based

PV Inverters Market Survey

Transformerless-based

Source : Photon


34 34

Both technologies are on the market! Efficiency: 93-95%

DC

ACGrid

PV

Array

DC

DC

On Low Frequency (LF) Side

DC

AC

GridPV

Array

DC

AC

AC

DC

On High Frequency (HF) Side

PV Inverters with Boost Converter and Isolation

DC/AC DC/AC AC/DC

Grid

N

L

FilterFilterFB boost with HF trafo FB inverterFilterPV Array

S5 S7

S6 S8

S1 S3

S2 S4

D1 D3

D2 D4

D5 D7

D6 D8

VPE

Boosting inverter with HF trafo based on FB boost

converter

DC/ACDC/DC

Grid

N

L

FilterFilterBoost without trafo FB inverterFilterPV Array

S5

S1 S3

S2 S4

D1 D3

D2 D4

D5

LF Trafo

VPE

Boosting inverter with LF trafo based on boost

converter


35 35

DC

DC

DC

ACGrid

PV

Array

•High efficiency (>95%)

•Leakage current problem

•Safety issue

•Efficiency > 96%

•Extra diode to bypass boost when Vpv > Vg

•Boost with rectified sinus reference

N

LS5

S1 S3

S2 S4

D1 D3

D2 D4

D5

VPELeakage circulating current

•Time sharing configuration

Full Bridge Inverter with Boost Converter

N

LS5

S1 S3

S2 S4

D1 D3

D2 D4

D5

VPELeakage circulating current

• Typical configuration

Transformerless PV Topologies with Boost Stage


36 36

No common mode voltage VPE free for high frequency low leakage current

Max efficiency 96.5% due to reactive power exchange between the filter and CPV during freewheeling

and due to the fact that 2 switched are simultaneously switched every switching

This topology is not special suited to transformerless PV inverter due to low efficiency!

Single-Stage Transformerless PV Topology


Full-bridge

CPV

O

vg

LCL- FilterD1

D2

D3

D4

A

BPV Panels

iPV

CP

S1

S2

S3

S4

iCMVGround

vPE

Full Bridge Inverter with

Different Modulation Schemes

Unipolar Modulation

Bipolar Modulation

vAO+vBO=2vPEvAO+vBO=2vPE

t [4 ms/div] t [4 ms/div]

iCMV=CpdvPE

dt

Bipolar Modulation Unipolar Modulation

Bipolar Modulation

37 37

High Efficiency Transformerless PV Topologies


DC Bypass

CPV1

vg

CPV2

SD5

SD6

D7

D8

Full-Bridge

iPV

LCL- Filter

SD1

SD2

SD3

SD4

O

A

BPV Panels

CP

DC Bypass

vgCPV

SD5

Full-Bridge

iPV

LCL- Filter

SD1

SD2

SD3

SD4

O

A

BPV Panels

CP

H5 Transformerless Inverter (SMA)

H6 Transformerless Inverter (Ingeteam)

Efficiency of up to 98%

Low leakage current and EMI

Unipolar voltage accross the filter,

leading to low core losses

High efficiency


DC bypass switches rating: Vdc/2

Unipolar voltage accross the filter

38 38

High Efficiency Transformerless PV Topologies


AC Bypass

SD5

SD6

Full-Bridge

iPV

CPV

vg

SD1

SD2

SD3

SD4

LCL- Filter

O

A

BPV Panels

CP

AC BypassFull-Bridge

iPV

vg

SD1

SD2

SD3

SD4

LCL- Filter

O

A

BPV Panels

CP

CPV1

CPV2

SD5

HERIC - Highly Efficient and Reliable Inverter Concept (Sunways)

FB-ZVR – Full Bridge with a Zero Voltage Rectifier (T. Kerekes, etc)

High efficiency of up to 97%

Very low leakage current and EMI

Low core losses

Efficiency of up to 96%


Unipolar voltage accross the filter,

leading to low core losses

39 39

NPC Topologies for PV Applications

Three-level output. Requires double PV voltage input in comparison with FB.

The switching ripple in the current equals 1x switching frequency high filtering needed

Voltage across filter is unipolar low core losses

VPE is equal –Vpv/2 without high frequency component low leakage current and EMI

High max efficiency 98% due to no reactive power exchange, as reported by Danfoss Solar TripleLynx

series (10/12.5/15 kW)


CPV1

CPV2

D5

D6

LCL- Filter

SD1

SD2

SD3

SD4

AB

N

vg

CPV1

CPV2

LCL- Filter

SD1

SD2

SD3

SD4

AB

N

vg

Neutral clampled half-bridge Conergy neutral point clampled inverter

Control Structure for a PV System


Basic functions –

all grid-tied inverters

► Grid current control

► DC voltage control

► Grid synchronization

PV specific functions –

common for PV inverters

► Maximum power point tracking – MPPT

► Anti-Islanding (VDE0126, IEEE1574, etc.)

► Grid monitoring

► Plant monitoring

► Sun tracking (mechanical MPPT)

Ancillary support –

in effectiveness

► Voltage control

► Fault ride-through

► Power quality

► …

PV Panels/

StringsPPV

Boost

iPV vPV

vg

ig

Q

Ambient

Temperature

Solar

Irradiance

DC

DC

DC

AC

CPV Cdc Inverter Filter

vdc PWMPWM

Xfilter

Communication Supervisory command

from DSO/TSO

Mission Profiles

Grid2/3

PV Panel/Plant

Monitoring

Maximum Power

Point Tracking

Grid Support

(V, f, Q control)Energy Storage

Ancillary Services

PV System Specific Functions

Basic Control Functions

Current/Voltage Control

Fault Ride Through

Grid SynchronizationVdc Control

Monitoring and Control

Anti-Islanding

Protection

Harmonic Compensation Constant Power Generation Control

Po


Challenge of Power Electronics in Renewable Energy

Systems


Cost of Energy (COE) T

yp

ica

l L

CO

E r

an

ge

s U

SD

/ k

Wh

Cost of fossil fuel

generation

&Cap O M

Annual

C CCOE

E

CCap – Capital cost

CO&M– Operation and main. cost

EAnnual – Annual energy production

Determining factors for renewables

- Capacity growth

- Technology development


Needs for Lower Cost of Wind Power

Different trends

But the Cost of Energy will be reduced


Needs for Lower Cost of PV Power

PV module cost should be reduced by 2/3

Power electronics needs also reduce cost by 1/2

Installation cost should be reduced by 2/3

US DOE cost reduction goals to achieve $1/w by 2020.

(Source: Adapted from IRENA renewable energy technologies: cost analysis series -Solar Photovoltaics)

SiC Devices

45

Source D, Boroyevich - CPES

Major SiC Device Developers

January 27, 2012 DB-23

600 V 1200 V 1700 V 3-7 kV 10 kV

Schottky

Blocking

Voltage

JFET Normally-on/-off

JFET Normally-off

Schottky diode

Schottky diode JFET

Normally-on

Schottky diode Super-junction

BJT

Thyristor 6.5 kV

BJT

MOSFET

Schottky diode

Schottky MOSFET MOS

MOSFET

Mainstream: 1.2 kV switches

A lot of research

going on for high-

voltage SiC devices

MAINSTREAM


First PV inverter based on SiC JFET

46

• SMA 20000TLHE-10 – 20 kW, 3 phase – 99.2%

• Light weight – 45 kg (1/2 of normal)

• Cooling minimized

• Conergy topology realized with Infineon

modules

• SiC JFET with IGBT free whelling

Source Photon Intl – Dec 2011

vc

N

vb va

N

Ta2 Ta3

Tb2 Tb3

Tc2 Tc3

Tb1 Tc1Ta1

Tb4 Tc4Ta4

Source : Infineon – Easy 1 b Modules


Simpler topologies with SiC JFET

47

vc

N

vb vaTa2

Tb1 Tc1Ta1

Tb2 Tc2

• Back to 2 level topologies!

• “Only” by doubling the switching frequency to 32 kHz, same efficiency of 98% as NPC-3L@16 kHz

• Half components count and lower footprint/weight

• Practical zero-reverse recovery with SiC diodes

Source B. Burger - Frunhofer


WBG Devices

48

Wide-Band-Gap Devices: Ways to Higher Power Density

January 27, 2012 DB-4

WBG

devices

≤ 200 400 ~ 600 ≥ 1200 Voltage (V)

Power (W)

10

100

1k

10k

GaN HEMTs MHz switching

Low conduction loss

Conduction

loss

Switching

loss

High-temp.

operation

Smaller cooling

system size

High-freq. passive

components

Smaller

passives sizes Improved

power

density

GaN diodes & transistors

SiC Schottky diodes

Better FOM, Competitive cost

No reverse recovery

SiC BJTs / IGBTs

MOSFETs / JFETs

Schottky / PiN diodes

High voltage

High temperature

Source: D. Boroyevich - CPES


Failures of Power Electronic Systems


Field Experience of Wind Turbines – Normalized Downtime

(Source: Reliawind, Report on Wind Turbine Reliability Profiles – Field Data Reliability Analysis, 2011.)

Power module

Rotor

module

Control

& Commons

NacelleDrive

trainAuxiliary system Structure

Power

converter

18.4% Pitch

system

23.3% Yaw system

7.3%Gearbox

4.7%



Power module

Rotor

module

Control

& Commons

NacelleDrive

trainAuxiliary system Structure

Power

converter

13%Pitch

system

21.3%

Yaw system

11.3%Gearbox

5.1%

Field Experience of Wind Turbines – Normalized Failure Rate

(Source: Reliawind, Report on Wind Turbine Reliability Profiles – Field Data Reliability Analysis, 2011.)



5 Years of Field Experience of a 3.5 MW PV Plant

(Data source: Moore, L. M. and H. N. Post, "Five years of operating experience at a large, utility-scale photovoltaic generating plant,"

Progress in Photovoltaics: Research and Applications 16(3): 249-259, 2008)

PV Inverter

37%

PV Panel

15%

Junction

Box

12%

System

8%

ACD

21%

DAS

7%

PV Inverter

59%

PV P

anel

6%System 6%

ACD

12%

DAS

14%

Unscheduled maintenance events by subsystem. Unscheduled maintenance costs by subsystem.

(ACD: AC Disconnects, DAS: Data Acquisition Systems)


Semiconductor 21%

Capacitor30%

PCB26%

*Data sources: Wolfgang E., “Examples for Failures in Power Electronics Systems,” in EPE Tutorial ‘Reliability of Power Electronic Systems’,

April 2007.

Failure root causes distribution for power electronic systems*

(% may vary for different applications and designs)

Critical Components in Power Electronic Systems

(http://www.alibaba.com)

(www.abb.com)


Approaches to Reduce Cost-of-Energy

&Cap O M

Annual

C CCOE

E

CCap – Capital cost

CO&M– Operation and main. cost

EAnnual – Annual energy production

Approaches Important and related factors Potential

Lower CCap Production / Policy +

Lower CO&M Reliability / Design / Labor ++

Higher Eannual Reliability / Capacity / Efficiency / Location +++

Reliability is an efficient way to reduce COE – lower CO&M & higher Eannual !


Shift of Reliability Analysis Approaches for PE

Reliability analysis of PE in the future

► More considerations of mission profile

► Root cause based

► Failure mechanism modeling

► Robustness validations

► More predictable and controllable

Reliability analysis of PE in the past

► Less dependent on mission profile

► Observations and statistics based

► Handbook/guideline calculation

► Testing under harsh conditions

► Hard to predict and control


Multi-disciplines for physics-of-failure approach

Ele

ctr

onic

s Pow

er

Control

Power

Electronics

Circu

its

Sta

tic

equip

ment

Rota

ting

equip

ment

Continous

Devi

ces

Sampled

data

In 1974, William E. Newell

defined power electronics as a technology

based on multi-disciplines.

Physics-of-failure approach for

power electronics reliability is also

based on multi-disciplinary knowledge.

Pow

er

Ele

ctr

onic

s

Relia

bility

Engin

eerin

g

Structure

Physics

Power

Electronics

Reliability

Ele

ctro

nic

s

Sta

tistics

Valid

atio

n

Physics-of-

failure

Control

Packaging &

structure

Pow

er


Reliability prediction of power electronics

Robustness margins

Mean cumulative failure rate

(MCF) Curve

Lifetime

Loading

profileReliability

information

Converter

Design

Mission

Profile

Stress Analysis

· Mission analysis

· Load estimation

· ...

Strength Modeling

· Failure mechanism

· Accelerating test

· Field feedback

· ...

Variation & Statistics

· System combination

· Stress/devices variation

· Production robustness

· ...

Lifetime

2L converter

690 Vrms

Filter

2L converter

Grid

1.1 kVDC

IGBT

Wind turbine

Generator

0%

5%

10%

0 1000 2000

M…


Lifetime prediction of IGBT in wind power converter

Converter design

2L converter

690 Vrms

Filter

2L converter

Grid

1.1 kVDC

IGBT

Wind turbine

Generator

Win

d s

pe

ed

(m

/s)

Am

bie

nt T

em

p. (º

C)

Time (hour)

Vw

Ta

Wind and temperature profile –mission profiles.


Thermal stress of IGBT in different time-scales in WTS

Mechanical ElectricalEnvironmental

sec

Medium term

(Mechanical control)

Long term

(Ambient change)

Short term

(Converter control)

houryear millisec

Thermal stress is focused under different details and time constants.

Just like the lenses with different focus lengths in photography.

1 year, 3 hours step 3 hours, 1 second step 0.2 second, 0. 01 millsec step


Procedure for lifetime estimation of wind power converter

Stress

analysis Total

Lifetime

Strength

model

Mission profile 1 year

Wind Distribution

Wind Reconstruction

Vwavg=1 m/s @ 3 hour

Wind Reconstruction

Vwavg=29 m/s @ 3 hour

Extended

to 1 year

Extended

to 1 year

Weighting factors W1m/s-W29m/s

Miner Rule…

…

…

…

Stress

analysis

Strength

model

Time span: 3 hours, step: 1 second

Loading Profile

Generation Lifetime

Lifetime

Estimation

Mission profiles

Time span : 1 year, Step: 3 hours

Influenced by environmental change.

Long term analysis up years.

Larger time step are needed.

Mission profile is translated to device

lifetime.

Long-term lifetime estimation:

Medium- & short- term lifetime estimation:

Influenced by mechanical behavior.

Medium term analysis - hours.

Moderate time step - seconds.

More detailed models are necessary.


Strength models of IGBT (cycles to certain failure rate)

Life time model from ABB Life time model from Semikron


Lifetime of IGBT by long term thermal loading

Consumed life time vs.

different failure mechanisms.

Co

nsu

me

d B

10

life

tim

e / y

ea

r (%

)

B solder – Baseplate solder failures.

C solder – Chip solder failures.

Bondwire – Bond wire failures.

B10 life time – Lifetime when device has 10 % failure rate.


Summary of lifetime estimation in different time scales

0.0

0.5

1.0

1.5

2.0

2.5

3.0

B Solder C Solder Bondwire

Medium term

Long term

Co

nsu

me

d B

10

life

tim

e (

%)

Wind speed (m/s)

Co

nsu

me

d B

10

life

tim

e (

%)


different wind speeds.


different failure mechanisms.

Summary


► A solution for the long term future in society

► Cost of Energy should be further reduced

► Increased power production close to the consumption place

► Coordinated control of production and consumption

► Future grid configurations may be different – but intelligent

► Systems should be able to run in on-grid and off-grid modes

► PV-plants will get same specifications as wind turbines

► Wind turbines have been the fastest growing in MW but PV will come

► Wind turbine technology – better performance

- Full scale power electronics

- New generator concepts (e.g. PM, gearless)

- Larger size – lower cost per kWh

- Reliability – a key to lower cost of Energy

Power Electronics for renewable energy :

Wind Turbines and Photovoltaic Systems


► A solution for the long term future in society

► Smart grid pushed by renewable

► Increased power production close to the consumption place

► Coordinated control of production and consumption

► Future grid configurations may be different – but intelligent

► Systems should be able to run in on-grid and off-grid modes

► PV-plants will get same specifications as wind turbines

► Wind turbines have been the fastest growing but PV will come

► Wind turbine technology – better performance

- Full scale power electronics

- New generator concepts (e.g. PM, gearless)

- Larger size – lower cost per kWh

► A university-industry collaborated center has been established to advance

the research progress in reliability of power electronic, especially for the

applications in renewable energy systems.

Power Electronics

enabling renewable energy into an intelligent grid


References 1. H. Wang, M. Liserre, and F. Blaabjerg, “Toward reliable power electronics - challenges, design tools and opportunities,” IEEE Industrial

Electronics Magazine, Jun. 2013 (in press).

2. 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.

3. F. Blaabjerg, Z. Chen, and S. B. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. on Power

Electron., vol. 19, no. 4, pp. 1184-1194, Sep. 2004.

4. F. Blaabjerg, M. Liserre, and K. Ma, “Power electronics converters for wind turbine systems,” IEEE Trans. on Ind. Appl., vol.48, no.2, pp.708-

719, Mar-Apr. 2012.

5. S. B. Kjaer, J. K. Pedersen, and F. Blaabjerg, “A review of single-phase grid connected inverters for photovoltaic modules,” IEEE Trans. on Ind.

Appl., vol. 41, no. 5, pp. 1292-1306, Sep. 2005.

6. K. Ma, F. Blaabjerg, and M. Liserre, “Thermal analysis of multilevel grid side converters for 10 MW wind turbines under low voltage ride

through”, IEEE Trans. Ind. Appl., vol. 49, no. 2, pp. 909-921, Mar./Apr. 2013.

7. K. Ma, M. Liserre, and F. Blaabjerg, “Reactive power influence on the thermal cycling of multi-MW wind power inverter”, IEEE Trans. on Ind.

Appl., vol. 49, no. 2, pp. 922-930, Mar./Apr. 2013.

8. C. Busca, R. Teodorescu, F. Blaabjerg, S. Munk-Nielsen, L. Helle, T. Abeyasekera, and P. Rodriguez, “An overview of the reliability prediction

related aspects of high power IGBTs in wind power applications,” Journal of Microelectronics Reliability, vol. 51, no. 9-11, pp. 1903-1907, 2011.

9. E. Koutroulis and F. Blaabjerg, “Design optimization of transformerless grid-connected PV inverters including reliability,” IEEE Trans. on Power

Electronics, vol. 28, no. 1, pp. 325-335, Jan. 2013.

10. K. B. Pedersen and K. Pedersen, “Bond wire lift-off in IGBT modules due to thermo-mechanical induced stress,” in Proc. of PEDG’ 2012, pp.

519 - 526, 2012.

11. S. Yang, D. Xiang, A. Bryant, P. Mawby, L. Ran and P. Tavner, “Condition monitoring for device reliability in power electronic converters: a

review,” IEEE Trans. Power Electron., vol. 25, no. 11, pp. 2734-2752, Nov., 2010.

12. M. Pecht and J. Gu, “Physics-of-failure-based prognostics for electronic products,” Trans. of the Institute of Measurement and Control , vol. 31,

no. 3-4, pp. 309-322, Mar./Apr., 2009.

13. Moore, L. M. and H. N. Post, “Five years of operating experience at a large, utility-scale photovoltaic generating plant,” Progress in

Photovoltaics: Research and Applications 16(3): 249-259, 2008.

14. Reliawind, Report on Wind Turbine Reliability Profiles – Field Data Reliability Analysis, 2011.

15. D. L. Blackburn, “Temperature measurements of semiconductor devices - a review,” in Proc. IEEE Semiconductor Thermal Measurement and

Management Symposium, pp. 70-80, 2004.

16. Avenas, Y., L. Dupont and Z. Kahatir, “Temperature measurement of power semiconductor devices by thermo-sensitive electrical parameters -

A review,” IEEE Trans. Power Electron., vol. 27, no. 6, pp. 3081-3092, Jun., 2010.

17. K. Kriegel, A. Melkonyan, M. Galek, and J. Rackles, “Power module with solid state circuit breakers for fault-tolerant applications,” in Proc. of

Integrated Power Electronics Systems (CIPS), pp. 1-6, 2010.

18. ZVEL, Handbook for robustness validation of automotive electrical/electronic modules, Jun. 2008.


References

1. K. Ma, F. Blaabjerg, “Loss and thermal redistributed modulation methods for three-level neutral-point-clamped wind power inverter undergoing

Low Voltage Ride Through”, IEEE Trans. on Industrial Electronics, 2013. (Also in Proc. of ISIE’ 2012, pp. 1880-1887, 2012).

2. K. Ma, F. Blaabjerg, “Thermal Optimized Modulation Method of Three-level NPC Inverter for 10 MW Wind Turbines under Low Voltage Ride

Through,” IET Journal on Power Electronics, vol. 5, no. 6, pp. 920-927, 2012.

3. K. Ma, F. Blaabjerg, M. Liserre, “Operation and Thermal Loading of Three-level Neutral-Point-Clamped Wind Power Converter under Various

Grid Faults,” IEEE Trans. on Industry Applications, 2013.

4. K. Ma, M. Liserre, F. Blaabjerg, “Reactive Power Influence on the Thermal Cycling of Multi-MW Wind Power Inverter,” IEEE Trans. on Industry

Applications, vol. 49, no. 2, pp. 922-930, 2013. (Also in Proc. of APEC’ 2012, pp. 262-269, 2012.)

5. A. Isidori, F.M. Rossi, F. Blaabjerg, K. Ma, “Thermal Loading and Reliability of 10 MW Multilevel Wind Power Converter at Different Wind

Roughness Classes,” IEEE Trans. on Industry Applications, 2013.

6. K. Ma, F. Blaabjerg, M. Liserre, “Electro-thermal model of power semiconductors dedicated for both case and junction temperature estimation,”

Proc. of PCIM’ 2013, 2013.

7. K. Ma, F. Blaabjerg, “Reliability-Cost Models for the Power Switching Devices of Wind Power Converters,” Proc. of PEDG’ 2012, pp.820-827,

2012.

8. K. Ma, M. Liserre, F. Blaabjerg, “Lifetime Estimation for the Power Semiconductors Considering Mission Profiles in Wind Power Converter,” in

Proc. of ECCE’ 2013, 2013 (in press).

9. F. Blaabjerg, M. Liserre, K. Ma, “Power Electronics Converters for Wind Turbine Systems,” IEEE Trans. on Industry Applications, vol. 48, no. 2,

pp. 708-719, 2012.

10. K. Ma, F. Blaabjerg, “The Impact of Power Switching Devices on the Thermal Performance of a 10 MW Wind Power NPC

Converter,” Energies 5, no. 7: 2559-2577, 2012.

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