1. Course date 22 September 2010
Course place DTU Lyngby, Copenhagen
EES-UETP Course title
Grid connected vehicles
Capabilities and characteristics
Egil Falch Piene
THINK Global AS
Norway

3. History
• Founded 19 years ago in Norway
• The first prototype predecessor to today’s modern
THINK City was developed in 1991
• The first generation THINK City was produced
from 1999-2003
• Ford Motor Company owned and invested heavily
in THINK between 1999-2003
• In 2006 Norwegian investors bought THINK and
have invested over $120 million to further develop
the latest generation THINK City
• Production moved to THINK’s strategic partner
and shareholder, Valmet Automotive of Finland,
in late 2009

4. EV design requirements
1. Optimize for energy efficiency and range
2. Optimize for cost and driving performance
3. Optimize for basic and sneaky design
4. Optimize for grid conditions and battery life
Think is doing "practical innovation"

5. Scope of this presentation
• Description of system in an electric car
conductively connected to the grid, with
AC transferred to an on-board charger
• Highlight some specifics for systems
integration, with focus on the modules
involved in the charging process
• Briefly discuss regulation services from a
user and vehicle perspective

6. Questions in mind
• What will be needed to prepare for the
charging infrastructure, so the grids can
supply many simultaneously connected
EVs?
• Are the vehicles being designed well
enough, so when many connected they do
not aggravate conditions in the grids?

7. Block diagram of modules
AC-charging from a 1-phase or 3-phase source
AC AC DC
COM Charging On-board Traction
Station Charger Battery
L1
L2
L3
N
PE
Vehicle CAN
COM
Vehicle BMS
Controller
Grid side Vehicle side

8. Plug-in vehicles today
• Typical for plug-ins today, is that they
charge with the power available, without
taking care of other loads or even any
other grid condition
• The vehicle charger system and the user
takes for granted that there are energy
and grid capacity available

9. Charging time versus interface
Gain of 80% State of Charge
Battery size: 25 kWh
Total efficiency: 80%
Courtesy of BRUSA www.brusa.biz

10. Power x time = km
km/charge-hour
Source Transfer EV * PIHV Th!nk City
• 230V 1ph 16A 3.6kW 18 7 17 (3,2kW)
• 400V 3ph+N 16A 11kW 55 - 51 (9,6kW)
• 400V 3ph+N 32A 22kW 110 - -
• 400V 3ph+N 63A 44kW 220 - -
• 690/400VAC ** DC 50kW 250 - TBD
* Example: General EV with ca 200 Wh/km consumption, "Plug-to-Wheel"
** CHAdeMO
>400 Wh/km 190 Wh/km

11. Block diagram of modules
DC-connected from an off-board charger, bypasses the AC on-board charger
AC DC DC
On-board
DC Charger
COM Traction
L1 Off-board Battery
Power relay
L2 control unit
L3 Charging
N Station
PE
Vehicle CAN
COM
Vehicle BMS
Controller
Grid side Vehicle side

12. Front - end
• Charging station • Today's Li-ION
– Provide energy traction batteries
– Electrical safety – 90 - 130 Wh/kg
– Forward available – 150 - 200 Wh/l
maximum current – 450 - 600 $kWh
– Link communication
– Metering energy
• Battery pack size for
– Payment
an usable EV
– IEC/EN 61851-1
– 15 - 40 kWh
with sub standards
– 150 - 400 kg

13. EV battery monitoring system
• BMS is a highly integrated module with
specific software
• Protection for overload, overcurrents,
overheat, overcharge
• Doing measurements and calculations
• Taking care of cell balancing
• HV isolation monitoring towards chassis
• Diagnostics and communication

14. On-board Charger
• The input voltage range shall without any
configuration, cover the voltages available
in all domestic power systems

15. Input voltage range
• Japan = 100 V to UK = 240 V ±10%
• which give 90 - 264 V + margin
• which give ≈ 85 - 275 V
• @ 50 - 60 Hz

16. Output voltage range
• The output voltage range need to match
the on board traction battery system
• Li-ION cells may have voltages varying
from 2.5 to 4.2V - depending its state of
charge (SOC)
• A modern EV will typically have (ca) 100
cells in series, which gives an operating
voltage range of 250 to 420V

17. - further properties
• Efficiency as high as possible
• Power output as linear as possible
• Conducted noise as low as possible
• Galvanic isolation (grid to traction battery)
• Power factor correcting
• Must respond to a control signal
• Light weight
• Automotive requirements *

18. HE rectifier circuits
DC out
AC in
Transistor Transistor
drive signals drive signals
Primary side
Secondary side DSP CAN
DSP
SPI
Courtesy of ELTEK VALERE www.eltekvalere.com

19. HE rectifier efficiency
100%
98%
96%
94%
Efficiency
92%
90%
HE rectifier
88%
86% Standard
rectifier
84%
82%
0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Load
Courtesy of ELTEK VALERE www.eltekvalere.com

20. Energy consumption and loss
• Assumptions
– 25 kWh battery with 5% internal system loss
– 3 kW on-board charger
– Average daily depth of discharge 60%
– 240 commute days pr year
• Energy delivered to battery
– Per day: 25 kWh x 0.6 x 1.05 = 15.75 kWh
– Per year: 15.75 kWh x 240 = 5 749 kWh
• On-board charger conversion losses
– 90% efficiency: 420 kWh per year
– 95% efficiency: 199 kWh per year
• Energy saved pr year: = 221 kWh

21. Power factor correction & noise
• Power supplies sold and used in Europe
must be compliant to the below standard,
which sets the limits for grid current
harmonics (up to 2 kHz)
• For power supplies larger than ca 250 W,
active power factor correction is necessary
to reduce feedback of harmonic currents
EN 61000-3-2

22. Grid current harmonics
16
Measurements from a 3 kW unit @ 230 V
14
12
1. Harmonic (50 Hz)
10
Ampere
Measured harmonics
8
EN61000-3-2 limits
6
4
2
0
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39
Harmonic number
Courtesy of ELTEK VALERE www.eltekvalere.com

23. Automotive requirements
• Vibration resistive
and mechanical
stability
• Wide temperature
range
• Efficient cooling
• Sealed enclosures
and connectors
• High voltage
isolation

24. Single loop charging regulation
• In a traditional battery charger circuit, the
regulation is based on the battery's need
COM Charging On-board Traction
Station Charger Battery
L1
L2
L3
N
PE
Vehicle CAN
COM
Vehicle BMS
Controller

25. Effects of negative impedance
• If the grid voltage drops, a connected
charger with single loop regulation would
increase the input current to maintain a
constant current or power output
• The increased input current will represent
a heavier load that may even drop the
voltage further down
• The max current allowed from the charging
station, must be registered by vehicle

26. AC current regulation loop
• An EV prepared for Smart Charging would
need one additional regulation loop
COM Charging On-board Traction
Station Charger Battery
L1
L2
L3
N
PE
Vehicle CAN
COM
Vehicle BMS
Controller

27. Coincidence factor
• If standardization for protection against
charger’s negative impedance is not
solved in the vehicle systems, a smart grid
signal could make control of distributed
power
• When dimensioning charging facilities for
fleets or many vehicles, the coincidence
factor would need to be carefully assessed

28. Balancing 3-phase
• Phase individual loads can by achieved
by the use of three single charger units
• Separate voltage measurement and
control
• Power 10 kW L1
~/=
L2
• Redundancy L3
~/=
DC
• Single phase ~/=
configurable N
CAN

29. Statement
Ph.D. Lars Henrik Hansen

31. Questions in mind 2
• How can plug-in
vehicles develop from
only being a load and
become a medium for
regulation services?
• What alternatives are
here now?

32. Regulation capable or not
• Dumb charging • V2G
Plugging in whenever In control from the
and wherever grid operator
• Timer charging • Smart Charging
Plug in, but no charge In control from the
until assumed valley grid operator or other
hours source

33. The sceptics response to V2G
• Uncertainty regarding the market for regulation
• New regulation technologies are emerging
• Which user incentives, "cash-back" only and
how will it be influenced by the volume of cars?
• User applicability, hence adaption, how combine
grid regulation with the need for driving range?

34. Smart charging scheduler
• Smart phone apps, • Not only as the
plan for the next drive control instrument for
the user,
• but as well a way of
spreading the
information towards
modern times for
greater concerns
about energy
consumption

35. Automakers V2G response
• Culture of designing machines for
transportation, not for storing electricity
• New technology, few standards
• Long time for development and validation
• Which battery life impact?
• Warranty aspects with battery system
• Safety for electrical hazards, liability issues
• Extra cost on the vehicle
• Different and new business models

36. Capacity retention

37. General impacts on Li-ION life
• High temperatures (> ≈ 55 C)
• Too heavy charge or discharge at low temp
• Too heavy charge or discharge at low SOC
• Too heavy charge or discharges
• Full or deep discharge cycles
• Storage empty (self discharge)
• Time

38. Charging efficiency, vehicle

39. Full V2G, not yet...
• Imperative that the owner of vehicle doesn’t
suffer an economic loss due to accelerated
retention of the battery
• Economic incentive must cover battery
system wear and degradation
• Warranty and legal aspects must be
transparent
• Comprehensive ‘Cash Back’ model is
needed for EVs and PHEVs

40. For realisation now is V2G light
• Providing regulation • The battery will not be
up and down worn more than in a
according to a regular operation
scheduled middle • Less losses in both
charge rate LV-grid and vehicle
• Vehicle should be in • Setup will probably
daily use, as require more vehicles
regulation service in the pool, to provide
would be possible only the same grade of
while charging up regulation compared
to real V2G

41. Control through infrastructure
• Local fleet servers for
power or time share
depending the local
capacity and number
of vehicles connected
and counting energy
• Control signal from
metering data
grid operator through
a fixed line • Aggregation server to
collect load data and
• Wireless not regarded
provide control signal
suitable for faster
response demands • Standardized protocol

42. - more "V2G light"
• The vehicles would • Target for charge rate
need a small extra response time
communication unit less than 3 sec
• The charging station • Aggregator to control
would need to be charging rate within
connected "on-line" predefined limits
• The user would need • Not only for fleets, the
a scheduler via web system can possible
or in a phone-app be general available

43. Added autonomous regulation
• In case the communication is lost,
– the vehicle charger system could enter an
autonomous mode, by providing regulation
with a fraction of the scheduled charge rate
with response to the line frequency
– a preset charge rate according to the
average daily/hourly load profile could work
as a back up and make the control
– The user would be notified via the phone-app
scheduler and still have the option to override

44. Local storage, regulation, solar, wind,
and fast EV-charging
Grid inverter
4 x,150kWpeak, bidirctional DCDC-converter
Frequency 50Hz Bidirectional, no isolation Photovoltaic panel
Switching frequency 24kHz Switching frequency 48kHz
MPP-Voltage up to 300V
with external prefilters 50kVA
20kWpeak
LV Grid
3 x 400 VAC+N AC
DC
DC
AC DC
DC
AC
DC
AC
DC
350 V DC
Direct connection to the vehicle
Main battery
2nd life EV batteries 10 x Na-NiCl, Z36
2 to 3 charging spots
250A capability (87W)
U-nominal = 370V DC
P-nominal = 250 - 500kWh
Courtesy of BRUSA P-peak = 500 - 1000kW
www.brusa.biz