Problems and Applications of
Power Converters for Smart Grid
and Energy Efficiency
Prof. Frede Blaabjerg
Fellow IEEE
IEEE, DL
DL-IAS
IAS
Institute of Energy Technology
Aalborg
g University,
y, Denmark
www.et.aau.dk
fbl@iet.aau.dk
Energy and Power Challenge
Main challenges in energy :
•
•
•
•
Sustainable energy
gy p
production ((backbone,, weather based))
Energy efficiency
Mobility
Infrastructure
Different initiatives :
-
EU Set-plan (20-20-20) and beyond
Danish Climate Commision
Many other countries
Globally many initiatives (Smat grid etc)
Content
∙
•
•
•
•
•
•
Electric Power System Architecture
Renewable Grid-Interactive Control
Smart Grid
System Topologies of Distributed Energy Resources
A Real World Example in Denmark
Energy Saving
Future Research Areas
Electric Power System Architecture
Electric Power System Architecture
Traditional Power System Architecture
• Centralized energy production
• Unidirectional power flow
• Vertical operation and control
Electric Power System Architecture
Challenges in Traditional Power System
Lolland Fuel Cell Micro CHP
Horns Rev offshore wind farm
• Grid integration of large-scale renewable energy systems
• Proliferation of distributed energy resources
• Several blackouts over the last years
• Increased energy demands
• Redesign the entire power system architecture?
Electric Power System Architecture
Electric Power System in Denmark
Key figures for Electricity Generation in 2008
Composition of renewable electricity generated in 2008
Western Denmark
Eastern Denmark
Source: Energinet.dk
Electric Power System Architecture
Development of Danish Electric Power System
Electric Power System Architecture
Development of Danish Electric Power System
Electric Power System Architecture
Development of the Power Balance in Western Denmark
Very high coverage of distributed generation.
Renewable Grid-Interactive Control
Renewable Grid
Grid-Interactive
Interactive Control
Off--shore ttechnolo
ogies
Horns Rev 160 MW
• 80 x 2MW (Vestas V80, pitched,
variable speed DFIG with
variable-speed,
gearbox)
• In operation for more than 3
years
y
Horns Rev - Vestas V80–2.0 MW
Rotor Diameter
80 m
Hub Height
70 m
Weight
245 tons
S
Start
Wind
d
4 m/s
/
Nominel Wind
13 m/s
Max Wind
25 m/s
Platform for helicopter hoist
Improved Power Control
Improved Corrosion Protection
Improved HSE Facilities
Renewable Grid
Grid-Interactive
Interactive Control
Off--shore ttechnolo
ogies
Nysted wind farm 158.4 MW
All turbines in operation
Sept 12, 2003
O&M
Service once a year
• Automated greasing
• extended SCADA
• Access by boat
Renewable Grid
Grid-Interactive
Interactive Control
 Wind turbine control level:
 DFIG control level:
 pitch control
 Control for DFIG:
 power limitation control
 active& reactive power
 Control of grid side converter
 Targets for control:
 DC-link voltage
 maximum power point operation
 unity
it power factor
f t
 power limitations for high wind speeds
 reactive power control
Conttrol of W
Wind Turbines
Renewable Grid
Grid-Interactive
Interactive Control
 PMSG control level:
 Maximum power point
 Control of grid side converter
 DC-link voltage
 unity power factor
 Wind turbine control level:
 p
pitch control
 power limitation control
 Targets for control:
 maximum power point operation
 power limitations for high wind speeds
 reactive power control
Conttrol of W
Wind Turbines
Renewable Grid
Grid-Interactive
Interactive Control
 SCIG control level:
 Maximum power point
 Control of grid side converter
 DC-link voltage
 reactive power
 Wind turbine control level:
 pitch control
 power limitation control
 Targets for control:
 maximum power point operation
 power limitations for high wind speeds
 reactive power control
Renewable Grid
Grid-Interactive
Interactive Control
Grid Co
onnectio
on Requirements
s
Grid Interfacing Demands
Renewable Grid
Grid-Interactive
Interactive Control
Grid Co
onnectio
on Requirements
s
Grid Codes
Danish Grid Code for
Distribution Networks
German Grid Code for
Transmission Networks
1
Danish Grid Code for
Transmission Networks
Renewable Grid
Grid-Interactive
Interactive Control
Grid Code for Transmission Networks
Power production regulation at Wind Farm Level
Priority 1
Priority 3
P i it 4
Priority
Priority 5
Priority 6
Priority 7
Renewable Grid
Grid-Interactive
Interactive Control
LVRT
x= 300-500 ms
Successive & non-symmetrical faults
E-On Grid Code
Grid support by 100% reactive current injection
Renewable Grid
Grid-Interactive
Interactive Control
Uniform dynamic performance of WT
Integration of energy storage elements in each WT
The system structure of a variable speed wind turbine integrating
with a battery storage system
Renewable Grid
Grid-Interactive
Interactive Control
Solar Powerr
A 3.15MWp Large PV Plant in Spain
(photo: http://www.solarig.com)
•
Large-scale, PV grid-connected systems (generally feed into the
medium voltage grid)
•
Power
o e rating
a g from
o 200
00 kWp to
o many
a y MWp (e
(e.g.
g 10MW
0
or more)
o e)
p o
•
The amount of the generated electricity depends on both the
meteorological conditions and the instantaneous grid load: energy
rejections
22
Renewable Grid
Grid-Interactive
Interactive Control
Solar Powerr
Large scale PV
Large PV Plants
L
Pl t (>
( 200 kWp):
) annuall power capacity
it (%)
as market share of total PV power capacity annually installed (MWp) [2]
[2] http://www.pv-power-plants.com
1
23
Renewable Grid
Grid-Interactive
Interactive Control
Solar Powerr
Large scale PV
Large PV Plants (> 200 kWp):
cumulative power capacity by
region in 2008 [2]
[2] http://www.pv-power-plants.com
Cumulative
C
l ti
power capacities
iti
in selected European countries in 2008 [2]
24
Renewable Grid
Grid-Interactive
Interactive Control
Solar Powerr
Large scale PV
One-line
One
line diagram of a Large (1MWp) PV Plant [4]: 4704 polycrystalline PV
modules in 4 PV substructures, 4 PV inverters, the PV system extends over
20000 m2
25
Smart GRID
Smart GRID
How do we control this – Smart GRID ?
Small scale
Large scale
Smart GRID
Future Power System
Three conceptual models for the architecture of future power system

Active Networks

‘Internet’ model

c og ds
Microgrids
‘Internet’
Internet model
Source: European Commission “New Era for Electricity in Europe. Distributed Generation: key issues,
challenges and proposed solutions.”
Smart GRID
Active Networks
 Possible evolution of
passive distribution
p
networks.
 Enabling technologies:
(1) Power electronics
(2) New ICT
Smart GRID
Microgrid
 Coordinated
C
di t d and
d controlled
t ll d electrical
l t i l subsystem
b
t
with
ith
• Multiple distributed energy resource units
• Multiple
p consumers
• Interconnections at distribution voltage level
• Capable of grid independent and grid dispatchable interactive operations
Source: RISØ SYSLAB
Smart GRID
Microgrid
c og d C
Classifications
ass cat o s
 Single Facility (<2MW) − Smaller individual facilities with multiple
loads e.
loads,
e g.
g hospitals,
hospitals schools
schools.
 Multi-Facility (2-5MW)
− Small to larger traditional CHP facilities plus a
few neighboring loads exclusively C&I.
 Feeder (5-20MW)
− Small to larger traditional CHP facilities plus
many or large neighboring loads, typically C&I.
 Substation (>20MW)
− Traditional CHP plus many neighboring loads
loads.
Will include C&I plus residential.
 Rural Electrification
− Rural villages of many emerging markets of India,
China Brazil etc
China,
etc., as well as rural settlements
found in Europe and North America.
Smart GRID
Microgrid
c og d C
Challenges
a e ges
 Distribution system protection and control practice is largely incompatible with
the Microgrid concept.
• Bi-directional
Bi directional power flows
• Unit level voltage and VAR support
 Non-conventional generation will require new unit control and protection
g
for successful Microgrid
g operation.
p
strategies
• Variability of renewable energy sources
• Low overload, short circuit ratings
• Power rate limits
• Potential for active load control (e.g., water and hydrogen production)
 Supervisory controls will be needed to achieve the full operating potential.
• Total energy optimization (electrical and thermal)
• Load management
• Unit commitment
• Aggregation and system performance
• Data acquisition
 Business, regulatory, and tariff structures are presently incompatible with
multiparty Microgrids.
Smart GRID
Microgrid Demo Projects
The Bornholm Island Multi Microgrid
in Denmark
Source: EU More Microgrid
System Topologies of Distributed
Energy Ressources
System Topologies of Distributed Energy Resources
General System Structure for a DER Unit
 Conventional rotary DER units
• Energy inertia
• Fixed speed,
p
, low efficiency
y
• Limited control of power flow
 Electronically-coupled DER units
• Inertialess
• Adjustable
djustab e speed, high
g efficiency
e c e cy
• Flexible control of power flow
System Topologies of Distributed Energy Resources
Conventional rotary DER units
The system structure of a fixed speed wind turbine
Elect onicall co pled DER units
Electronically-coupled
nits
The system structure of a variable speed wind turbine
System Topologies of Distributed Energy Resources
New Requirements from Microgrid Operations
CERTS microgrid operations − Uniform dynamic performance of DG Units
Integration of energy storage elements in each DG unit in the CERTS microgrid
The system structure of a variable speed wind turbine integrating with a battery storage system
System Topologies of Distributed Energy Resources
System Topologies of Power Electronics Interfaces
 Single-stage power conversion system
• Simplest configuration
• Bulky and expensive low frequency transformer
• Z-source and NPC multilevel converter are more attractive
 Commonly used two-stage power conversion system
• One stage controls the primary energy source (MPPT), the other performs grid requirements
• Decoupled control of power flow between the energy source side and the grid side converter
System Topologies of Distributed Energy Resources
Operating Conditions and Functions of DER Units
Grid
Forming
• Voltage and frequency control
• Load sharing
Grid
Feeding
• Power dispatch
• Voltage and frequency support
Grid
Supporting
• Maximum active power output
• Reactive power support
A Real World Project in Denmark
A Real World Project in Denmark
The Cell Project
The power system in western Denmark production capacity per voltage level
A Real World Project in Denmark
The Cell Project
A Real World Project in Denmark
The Cell Project
A Real World Project in Denmark
The Cell Project
A Real World Project in Denmark
The Cell Project
Energy Saving
Energy Saving
• Energy Consumption (dependent on global location)
• 1/3 electricity
• 1/3 heat
/ transport
p
• 1/3
• Issues
I
off importance
i
t
• Buildings (isolation, behaviour)
• New demands (etc. Cooling)
• Globalisation (production etc.)
Energy Saving
REFRIGERATOR
SOLAR CELLS
TELEVISION
DC
AC
SOLAR
ENERGY
LIGHT
TRANSFORMER
MOTOR
3
3
1 -3
3
PUMP
TRANSFORMER
POWER STATION
FACTS
ROBOTICS
COMPEN SATOR
INDUSTRY
TRANSFORMER
FUEL
CELLS

3
WIND TURBINE
FUEL
COMMUNICATION
TRANSPORT
TRANSPORT
COMBUSTION
ENGINE
DC
AC
POWER SUPPLY
ac
~
dc
=
Energy Saving
In the modern world 60% of all
electricity is consumed
by electrical motors
Energy Saving
Total annual energy
gy consumption
p
by
y motors:
(US 1995)
~
Power plant in Denmark produces:
Case
Power
1%
5%
10%
savings by reductions of
~ 7.65
7 65 TWh
~
3 power plants
~ 38.25 TWh ~ 15 power plants
~ 76.5 TWh ~ 30 power plants
765 x 10^9 kWh
765 TWh
~ 300 MW
2 6 TWh/year
2.6
~
Energy Saving
Problems / Demands
DEMANDS FOR ASD
Line iinterface
Li
t f
 Single/Three phase
 Harmonic Standards
 Regeneration
 EMI/RFI
 Line transients
 Unbalance
U b l
 Ride-through
Grid
F
Frequency

3
ASM
Converter
Field Bus
Control/Monitoring
 Control Methods
 Self-commisioning
 Application software
 Overload control
 Efficiency optimized
 Fault-detection
 Fault-handling
Interface





Bus-structure
Auto-configuration
Panel setup
C
Communication
Status-information
Performance can vary a lot
Sh ft performance
Shaft
f
 Speed range
 Torque-speed characteristic
 Dynamic response
 Sensor/sensorless
g ((flux))
 Braking
 Flying start
Energy Saving
General trends
•
•
•
•
•
•
•
Price p
pr. kW decreases
Weight pr. kW decreases
More intelligence in drives (internet etc.)
Global interconnection ((90 V – 380 V))
Converter and motor build together
Other motors are becoming an alternative
Power Electronics in g
general the key
y for success
R&D Needs in Energy Technology
R&D needs in Energy Technology
• Basic research (material, chemistry, etc)
•
•
•
•
•
•
•
•
•
•
Energy storage
CO2 reduction in power production incl. more efficient power plants
Behaviour change
More efficient cars/airplanes/ships
Create alternatives to fossil fuel (e.g. biofuel)
From Vaste to Value
More reliable and predictable power/energy systems
The energy and power market place
Better interplay between energy sources
Develope a 1-2 kW society
R&D needs in Energy Technology
More Electric Society
Energy Saving
Automation
Communication
Distributed power/ Renewable energy
Power Quality
Transportation
Aviation and Space
Appliance Applications
Power Transmission
Computers
2007
R&D needs in Energy Technology
More electric society
y
-
New (improved) devices
Power conversion technologies
Smart and CHEAP Integration (converter, system)
New applications (eg. LCD’s, wireless, RES..)
Virtual power prototyping (simulation etc)
Multi-disciplinary
Multi
disciplinary design (Electrical,
(Electrical Thermal,
Thermal Mechanical,
Mechanical EMI)
Reliability
Unity efficiency ASD’s (large energy consumers)
Intelligent Load management – combined with power production
High Compact Energy Storage devices (and cheap)
New concepts for transportation
Smart light technologies
Rare-earth material substitution
Smart grid – micro grid
Etc.
Some published papers in the field
A. Luna, P. Rodriguez, R. Teodorescu, F. Blaabjerg, "Low voltage ride through strategies for SCIG
wind
ind tturbines
bines in distributed
dist ib ted power
po e generation
gene ation s
systems,"
stems " Power
Po e Electronics
Elect onics Specialists
Conference, 2008. PESC 2008. IEEE , vol., no., pp.2333-2339, 15-19 June 2008
P. Rodriguez, A. Timbus, R. Teodorescu, M. Liserre, F. Blaabjerg, "Flexible Active Power Control of
Distributed Power Generation Systems During Grid Faults," Industrial Electronics, IEEE
Transactions on , vol.54, no.5, pp.2583-2592, Oct. 2007
P Rodriguez,
P.
R d i
A.
A Timbus
Ti b
, R.
R Teodorescu,
T d
M.
M Liserre,
Li
F.
F Blaabjerg
Bl bj
, "Reactive
"R
ti
Power
P
Control
C t l for
f
Improving Wind Turbine System Behavior Under Grid Faults," Power Electronics, IEEE
Transactions on , vol.24, no.7, pp.1798-1801, July 2009
F. Blaabjerg, R. Teodorescu, M. Liserre, A.V. Timbus,“Overview of Control and Grid Synchronization
for Distributed Power Generation Systems, IEEE Trans. on Industrial Electronics, Vol. 53, No. 5,
2006 pp. 1398
2006,
398 – 1409.
09
S. B. Kjaer, J.K. Pedersen, F. Blaabjerg, "A review of single-phase grid-connected inverters for
photovoltaic modules," Industry Applications, IEEE Transactions on , vol.41, no.5, pp. 12921306, Sept.-Oct. 2005
T. Kerekes, R. Teodorescu, C. Klumpner, M. Sumner, D. Floricau, P. Rodriguez, "Evaluation of threephase
h
t
transformerless
f
l
photovoltaic
h t
lt i inverter
i
t
t
topologies,"
l i " Power
P
El t
Electronics
i
and
d Applications,
A li ti
2007 European Conference on , vol., no., pp.1-10, 2-5 Sept. 2007
F. Blaabjerg , Z. Chen and S. B. Kjaer "Power electronics as efficient interface in dispersed power
generation systems", IEEE Trans. Power Electron., vol. 19, pp. 2004, pp. 1184-1194.
M. P. Kazmierkowski , R. Krishnan and F. Blaabjerg
Control in Power Electronics—Selected
Problems,Book,2002;AcademicPress
,
,
;
Z. Chen, J.M. Guerrero, F. Blaabjerg, “A Review of the State of the Art of Power Electronics for Wind
Turbines” IEEE Transactions on Power Electronics, Vol. 24, No. 8, pp. 1859-1875
A. Timbus, M. Liserre, R. Teodorescu, P. Rodriguez, F. Blaabjerg, “Evaluation of Current
Controllers for Systems”, IEEE Transactions on Power Electronics, Vol. 24, No. 3, 2009, pp.
654 664.
654-664.
F. BLAABJERG, R. Teodorescu, M. Liserre, A.V. TIMBUS,”Overview of Control and Grid
Synchronization for Distributed Power Generation Systems”, IEEE Trans. on Industrial
Electronics, Vol. 53 , No. 5, 2006, pp.1398 - 1409
Th k you for
Thank
f your attention!
tt ti !