Transcript Studio di un veicolo ibrido solare

INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Hybrid Solar Vehicles:
Perspectives, Problems,
Management Strategies
HYATT REGENCY
NOVEMBER 13-14, 2008
ISTANBUL
I.Arsie, G.Rizzo, M.Sorrentino
DIMEC, University of Salerno, Italy
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Outline
Introduction
HSV: models and results
Optimization of Management Strategies
The Prototype
Conclusions
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
The background
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
From conferences to cartoons
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Possible Solutions?
Kyoto Protocol: A possible
solution to fossil fuel depletion and
global warming is an increased
recourse to Renewable Energy
(RE).
Possible application to cars:
Fuels/Energy from RE (Bio-Fuels, H2)
Solar Cars
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Energy
1.5 106 km
Nuclear fusion into
the sun produces an
enormous amount of
energy, irradiated into
the space.
A very small part of the energy radiated by
sun strikes the Earth (a part over two
billions).
Solar energy is partly reflected to the space
(15%), partly used to evaporate water (30%)
and partly absorbed by plants, oceans and
land, and for men use (55%).
15%
55%
30%
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Energy vs. Energy
Consumption
The solar energy striking the US in
one day is almost equivalent to
the energy consumption for one
and a half year
=
+
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
PV Panels
Today's most common PV devices use a single-junction with poli-crystalline
silicon, with efficiency of about 12%
Use of mono-crystalline silicon results in higher efficiency (15% and more)
Multi-junction cell
Much of today's
research in multijunction cells
focuses on gallium
arsenide as one of
the component cells.
Such cells have
reached efficiencies
of around 40% under
concentrated sunlight
(Fresnel lens).
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
PV efficiency trends
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Panels Production and Prices
The production of photovoltaic
panels has remarkably increased
since 90’s in terms of installed
power.
Their cost, after a continuous
decrease and an inversion of
the trend occurred in 2004,
appears now quite stable
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Outline
Introduction
HSV: models and results
Optimization of Management Strategies
The Prototype
Conclusions
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Cars
Various propotypes of solar
cars have been developed, for
racing and demonstrative use
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Limits of Solar Cars
Solar Cars do not represent
realistic alternative to “normal” cars,
due to:
Limited power and performance.
Limited range.
Discontinuous energy source.
High cost.
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Hybrid Electric Vehicles
F.Porsche, 1900
Ford Escape
Buick Skylark, 1974
Honda Insight
Mercedes S400
Hybrid-Diesel
Peugeot 308
Hybrid-Diesel
Toyota Prius
GM Precept
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HEV and PV: a possible marriage?
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
About the dowry
Energy
Power
Conventional/Hybrid
car
PV panels
600 KWh
<50 KWh/day
50 kg gasoline tank
6 m2 @ 8.5KWh/m2/day
100 KW
< 1 KW
Solar Cars: lighter than Cars
HEVs: heavier than Cars
Q: Is solar energy a rich
dowry for a vehicle?
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Energy Balance in a Solar Car
Net solar energy available to propulsion [KWh/day]
Parking mode
Driving mode
E sun  E p  E d   p APV e sun
Daily time fraction spent
in parking mode
Daily time fraction
spent in driving mode
h sun  hd
h
   p APV e sun d 
h sun
h sun
esun=average insolation (KWh/m2day)
APV=effective panel area = APV,H+0.5 APV,V
PV=panel efficiency (=0.13)
: reduction factor due to charge/discharge processes in battery (=0.9)
: insulation reduction during driving, due to shadow (=0.9)
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Fraction
Continuous use (h=10) with
100% recourse to the sun can
be achieved only at very low
power (<1 KW).
2
2
APV
]=6 APV
]=0 Vol.[m3]=8.8997
6 mH2[m
@12%
or 3V [m
m2@24%
100
Driving
hours
per
day
Solar energy can represent a
significant contribution for
intermittent use (h=1-2) and
for limited average power.
Solar Energy %
80
For average power from 5 to 10
KW and driving hours from 1 to
2, solar contribution ranges
from 18% to 60%.
Are these values of power and
driving hours significant?
60
h=1
h=2
h=3
h=5
h=10
40
20
0
0
5
10
Car Average Power [KW]
Site: San Antonio, Texas
Yearly Averaged Data
15
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Statistics on Car Drivers
Some recent studies of the
UK government stated that
about 71% of UK users
reaches their office by car
46% of them have trips
shorter than 20 min
mostly with only one person
on board.
Source: Labour Force Survey,
http://www.statistics.gov.uk/CCI/nscl.asp?ID=8027
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Power Demand
Speed [km/h]
Power demand can
be determined
integrating the
longitudinal vehicle
model over a mission
cycle.
150
Extra-urban
Urban
100
50
0
0
200
400
600
800
1000
1200
800
1000
1200
Power [KW]
60
During urban drive,
limited average
power can be
required to drive a
small car.
40
20
0
-20
-40
0
200
400
600
Time [s]
Mass=1000 Kg - Length=3.75 m
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Effects of Position on Energy
Negligible differences between 2axis and 1-axis tracking systems.
Average Yearly Energy (KWh/year)
3000
2 axis tracking
1 axis tracking
Tilt=Latitude
Horizontal
Vertical (mean)
2500
Almost a factor 2 between
maximum and minimum latitudes.
For fixed panels, there is not a
relevant loss by adopting horizontal
position with respect to “optimal” tilt,
particularly at low latitudes.
Energy absorbed with vertical
position is significantly lower,
mainly at low latitudes.
46%
2000
1500
79%
1000
500
0
Adoption of moving solar roof for parking
phases can significantly increase solar
energy, particolarly at the high latitudes
0
20
40
60
Latitude (deg)
80
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Some HSV prototypes
Viking 23
Western Washington University
Ultra-Commuter
The University of Queensland
Tokyo University of Agriculture
and Technology
Solar Toyota Prius
By Steve Lapp
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Solar Prius
Prius with an aftermarket 215 W monocristalline
solar module with peak power tracking and a
95% efficiency DC-DC Converter
It is estimated that the PV Prius will consume somewhere between 17%
and 29% less gasoline than the stock Prius (range per day: 5-8 miles)
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Well to Wheel
H2
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV vs HEV
HEV ≠ Conventional Car + Electric Motor
HSV ≠ HEV + PV
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV vs HEV
Mission profile (HSV should be
optimized for urban driving)
Different SOC management
strategies.
Different structure (vehicle
dimension, hybrid architecture)
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV vs HEV control
SOC
In most HEVs, a charge
sustaining strategy is
adopted: the battery State Of
Charge (SOC) is unchanged
within a driving path.
driving path
Time
SOC
A suitable strategy for HSV
instead can restore the initial
SOC within a whole day,
considering battery charging
during parking time.
day
driving path
parking
ΔSOC
Time
Charge depletion
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Potential advantages of Series HSV
No mechanical link between generator and
wheels:
Very effective vibration insulation can be achieved
Less constraints for vehicle layout
Possible use of in-wheel motors with advanced traction
control techniques
Engines optimized for steady operation can be
used:
ICE designed and optimized for steady conditions
D.I. Stratified charge engine (4 or 2 strokes)
Micro gas turbine
Series architecture acts as a bridge towards the
introduction of fuel cell powertrains.
More suitable for V2G applications
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Vehicle to Grid (V2G)
V2G concept: to connect
parked electric driven
vehicles (electric, hybrid,
hybrid solar, fuel-cell) to the
grid by a two-way computer
controlled hook up.
The power capacity of the
automotive fleet is about 10
times greater than the
electrical generating plants (in
US) and is idle over the 95%.
Advantages:
Reduction of costs for peak power production.
Toward the distributed generation, with reduction of Transmission
and Distribution (T&D) costs.
Facilitate integration of intermittent renewable resources.
The value of the utility exceeds the costs for the two-way hook up
and for the reduced vehicle battery life.
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
V2G: Additional advantages for HSV
Possible use of motogenerator as cogenerator
for domestic use
Possibility to transfer
excess solar power
to the grid
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Engine control in a series HSV
In a series HSV, the Internal
Combustion Engine could
operate on the optimum
efficiency curve and
whenever possible at its
maximum efficiency
ICE Efficiency
Popt
ICE Power PICE
A
PMAX
B
Part load operation can be
avoided and substituted by
intermittent operation at
maximum efficiency
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /1
Parking
PV Panels
with sunlight
VMU
ICE
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /2
Hybrid
PV Panels
with sunlight
VMU
ICE
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /3
Electric Driving
PV Panels
with sunlight
VMU
ICE
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /4
Regenerative Braking
PV Panels
with sunlight
VMU
ICE
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /5
Recharge from grid
PV Panels
with sunlight
VMU
ICE
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
SHM – Operating Modes /6
“We believe that the most plausible
vehicle of the future is a plug-in hybrid...”
Power to grid
(V2G)
(Center for Energy and Climate Solutions, 2004)
PV Panels
Thermal
load
with sunlight
heat
ICE
VMU
EG
EM
Battery
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Flow Chart
CONTROL VARIABLES
Control Strategy for
EG – MPPT for PV
DESIGN VARIABLES
PV Panel Area and Position
– EG and EM Power – Car
dimensions – Materials
DESIGN SPECIFICATION
Power demand – Insolation
– HSV Structure
EXHOGENOUS VARIABLES
Fuel Price – Panel
Efficiency – Unit weight
and costs
MODELS
Energy Flows for HSV/CC – Car sizing - Weight - Cost
OUTPUT
Car Stability – Fuel Savings – Weight - Payback
Objective Function and Constraints
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Payback Optimization
min X PB X 
Gi  X   0
i  1, N G
 Objective Function: minimum Payback
 Inequality Constraints
Design variables X:
1.
2.
3.
4.
5.
6.
7.
8.
Electric Generator Power PEG
Electric Motor Power PEM
Horizontal panel area APV,H
Vertical panel area APV,V
Car length l
Car width w
Car Height h
Weight reduction factor of car chassis with respect to base value CWf
Solved by Sequential Quadratic Programming (Matlab routine FMINCON)
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Constraint Specification
PEG,min  PEG  PEG. max EG Power within lower and upper bounds
PtWHSV
1
PtWCV
lmin  l  lmax
wmin  w  wmax
Power to Weight ratio equal to the conventional
vehicle
Car dimensions within assigned limits, obtained by the
database of commercial vehicles
hmin  h  hmax
l l 
l 
    
 w  min w  w  max
h h
h
    
 w  min w  w  max
APV , H  APV max,H l , w
APV ,V  APV max,V l , w, h 
CW f  0.7
Length to width ratio and height to width ratio
within assigned limits, obtained by the database of
commercial vehicles
PV panels area compatible with car dimensions,
according to the given geometrical model
Car weight reduction factor not lower than 0.7
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Optimal design results
#
cf
€/kg
cPV
€/m2 €/W
P [/]
1
1.77
800/6.15
0.13
0
35.5
6.1
2
1.77
800/6.15
0.13
3
35.5
9.9
3
1.77
200/2.15
0.13
4
37
5.6
4
3.54
200/2.15
0.16
5.6
38.4
2.4
APV,H [m2] PEG [kW] PB [yrs]
A very good payback (2.4 years) is by
doubling fuel cost, reducing by 4 panel cost,
and considering 16% panel efficiency
Fuel Price ≈ 2.1 €/KG
Italy, June, 2008
PV Retail Price:
June 2008: 4.70 €/W
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
MPPT Techniques
Due to changing sun irradiance,
PV source must be matched to
the load to draw maximum
power.
Maximum Power Point
Tracking (MPPT) techniques
are adopted.
The presence of local maxima
occur during mismatched
conditions, due to shading
effects and temperature
variations in different parts of
the panel.
The characteristic may change
rapidly during driving
conditions, required advanced
MPPT control.
Uniform working conditions
300
250
200
150
100
50
0
0
5
10 15 20 25 30 35 40 45 50
120
100
Mismatched PV field
80
60
40
20
0
0
5
10 15 20 25 30 35 40 45 50
Power vs. voltage characteristic of a PV field
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Sources of mismatching
Different solar
irradiation levels due
to:
Clouds
Shadows
Different orientation of
parts of the PV field
Dirtiness
Tolerances (due to
manufacturing and/or
ageing)
Different types of
panels (different
models, photo-glass,
coloured) in the same
string
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
MPPT management of PV array
MPPT strategy are implemented to maximizing PV
efficiency throughout the day.
• Max Allowable Power
• Power given to the battery
P
Vi
MPPT
Vi
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Outline
Introduction
HSV: models and results
Optimization of Management Strategies
The Prototype
Conclusions
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV Modeling
Longitudinal model of the HSV protoype:
Pw  M HSV  g  v  Cr cos   sin   0.5 C x A v 3  M eff
PEM 
Pw
dv
v
dt
if
Pw  0
if
Pw  0
PEM  Pw  tr  EM
if
Pw  0
PB  PEM  PEG  AC / DC  PPV
if
Pw  0
PEM
 tr
  EM PEG  AC / DC  PB  PPV

= experimentally characterized
 Power at wheels
 EM Power
 Battery recharge
power
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Experimental characterization: EG and EM
The electric generator
was characterized
connecting a pure
resistive electrical load.
A 4° order polynomial
regression was
obtained.
EM efficiency is modeled
by a 3rd order polynomial
regression identified vs.
manufacturer technical
data.
EG [/]
0.35
Experimental
0.3
Simulated
0.25
0.2
0.15
0.1
0.05
0
0
1
2
3
Power [KVA]
4
5
6
EM [/]
0.9
0.85
0.8
0.75
0.7
experimental
simulated
0.65
0
2
4
6
8
Power [KW]
10
12
14
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Experimental characterization: the Battery pack
Battery is modeled applying the
Kirchoff law to an equivalent circuit.
The internal resistance was modeled
as a nonlinear function of state of
charge.
Model accuracy was checked against
experiments.
Rin
__
E0
Vr
a)
Vbatt
__
E0
b)
Vbatt
E0= battery open circuit voltage
Rin= battery internal resistance
Vr= internal voltage losses
Vbatt= effective voltage
Idis= discharging current
Ichg= charging current
0.025
Discharge
Charge
0.02
6
5.8
0
Ichg
Battery internal resistance [Ohm]
Experimental
Battery Model
6.2
Rin
Vr
Battery voltage [V] in discharge operation mode (a)
6.4
Idis
20
40
60
80
100
Current [A]
Battery voltage [V] in charge operation mode (b)
0.015
7.2
7
0.01
6.8
6.6
Experimental
Battery Model
6.4
6.2
0
20
40
60
Current [A]
80
100
0.005
0
0.2
0.4
0.6
State of charge [/]
0.8
1
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Experimental characterization: the PV array
60
The PV array has been
characterized by connecting
the converter output to a
resistive load.
experimental
simulated
PV Power [W]
50
40
PV = 10 %
(390 W/m2 irradiation)
30
20
10
0
0
15
20
25
PV Voltage [ V ]
30
35
40
45
Daily Average Energy [kWh/kWp/day]
6
5
4
3
2
1
0
JU
L
A
U
G
SE
P
O
CT
N
O
V
D
EC
 kW h 


 kW pday
A
1.44
E PV  E sun,day  PV  3.1
 450 W h/ day
10
10
E sun,day  3.1
10
JA
N
FE
B
M
A
R
A
PR
M
A
Y
JU
N
The average PV daily energy
was derived from an
experimental year-thorough
distribution:
5
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
ICE thermal transients
Engine temperature
dynamics is estimated by a
first order dynamic model
Engine temperature
90
t
K
80
70
T [°C]
T t   Tss  Tin  Tss e

Steady state temperatures and
time constants are assigned
for ICE on and ICE off events
ICE
operation
Tss [°C]
K [s]
ON
82
150
OFF
27
600
60
50
40
30
20
N=1
N=4
0
1000
2000
3000
Time [s]
4000
5000
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Thermal effects on power and SFC
Specific Fuel Consumption and
power are related to the ratio
between actual temperature and
its steady state value, starting from
experimental data for a SI engine
SFCss P 
SFCt  
 Teng 

f 
 Tss 
 Teng
P t   Pss  f 
 Tss



f  1   2 e
 Teng
 
 Tss

  3

Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Modeling of HC emissions
Due to the ICE intermittent use, HC
emissions occurring during warmup have to be accounted for.
[0-20] s: HC formation
mechanism modeled as a first
order process
HC [ppm]
800
Experimental warm-up HC dynamics
Engine Temp. [°C]
600
80
70
60
HCt   HCss  HCin  HCss e
1
HCin Tin  
Tin
400
t
K
Tin = 26 °C
50
40

200
Tin = 55 °C
30
20
0
50
100
150
1000
200
250
HC [ppm]
Time [s]
300
350
400
450
800
0
0
5
10
Time [s]
15
]20:..] s:
600
HCt   a  b  Teng
400
200
0
0
50
100
150
200
250
Time [s]
300
350
400
450
20
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Energy management strategy
In case of ICE intermittent
use, energy management for
HSV can be addressed via an
optimization analysis.
The decision variables X
include number of ICE starts,
starting time, duration and
ICE power level.
Day through charge
sustaining is achieved
constraining SOC variations.
 f , HSV  X dt
min X  m
Power
Traction power ICE Power
Minimum and maximum values
considered for state of charge
Time
SOCday  SOCf  SOC0  SOCp  0
SOC  SOCmin
SOC  SOCmax
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Simulation of HSV prototype: scenario analysis
The prototype was simulated
on a driving cycle composed
of 4 ECE-like modules.
HSV Specification
ICE power [kW]
Fuel
46
gasoline
Vehicle speed [km/h]
35
PEG [kW]
43
30
PEM [kW]
90
25
Number of battery modules [/]
27
20
15
PV horizontal surface APV,H [m2]
1.44
10
Coefficient of drag (Cd)
0.4
5
Frontal area [m2]
2.6
Weight [kg]
1465
0
0
2
4
6
8
Time [min]
10
12
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Control optimization results (DBM) 1/3
HSV power [kW]
Fuel economy improvement [%]
60
20
40
15
20
10
0
5
-20
PEG,N4 > PEG,N2
0
1
2
3
4
5
N. of starts
6
7
-40
0
8
1000
2000
3000
Time [s]
Traction power
EGN2
EGN4
4000
5000
Engine temperature [°C]
90
• Initially fuel economy increases
with engine starts due to the
higher degrees of freedom.
80
70
60
50
40
N
30
20
0
1000
N=2
N=4
N =8
Teng
2000
3000
Time [s]
4000
5000
• After 4 ICE-on, fuel economy
tends to decrease due to the
increasing impact of thermal
transients.
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Control optimization results (DBM) 2/3
HC [grams]
2
• HC emissions show an
increasing trend with number of
starts.
1.5
• A local minimum occurs at N =4.
1
• Such a behavior is due to the
different temperature trajectories.
0.5
0
1
2
3
4
5
N. of starts
6
7
8
Enginetemperature
temperature[°C]
[K]
Engine
HC emissions [g/h]
90
90
40
N=3
N=4
80
80
30
70
70
60
60
20
50
50
40
40
N=2
N=4
3
=4
N =8
30
30
20
20
00
1000
1000
2000
3000
Time [s]
4000
5000
10
0
0
1000
2000
3000
Time [s]
4000
5000
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Control optimization results (DBM) 3/3
HSV power [kW] - N = 4 (a)
60
45
30
15
0
-15
-30
0
• On average EG
operating
conditions fall in a
high efficiency
region.
drive
gen
1000
2000
3000
4000
5000
Time [s]
State of charge [/] N = 4 - (b)
0.8
0.75
0.7
0.65
0
1000
2000
3000
Time [s]
4000
5000
• SOC excursions
are satisfactorily
bounded
• Final SOC leaves
room for PV
charging during
parking phases
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Energy management optimization by
means of genetic algorithm (GA) search
As both integer and real variables are involved, the GA
search method was selected for such an analysis.
HC emissions and fuel consumption for cranking energy
have been also included in the objective function.
Binary representation of the optimization problem
Decision
variable
Definition
range
Precision
Number
of bits
NEG
[1 8]
1
3
tEG (min)
[0 78/ NEG]
0.073/ NEG
10
tEG (min)
[0 78/ NEG]
0.073/ NEG
10
PEG (kW)
[0 43]
0.040
10
GA parameters
Population size
70
Number of generations
100
Crossover probability
0.8
Mutation probability
0.033
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Control optimization results (GA) 1/2
EG and battery power trajectories [kW]
80
EG
Battery
60
40
20
0
-20
-40
0
10
20
30
40
Time [min]
50
60
70
80
70
80
Engine temperature [°C]
90
80
70
60
50
DBM
40
GA
30
20
0
10
20
30
40
Time [min]
50
60
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Control optimization results (GA) 2/2
Power at wheels [kW]
50
25
0
-25
-50
0
10
20
30
40
Time [min]
50
60
70
80
To be recovered in
the parking phase
SOC variation [/]
1
0.8
0.6
0.4
0
10
20
30
40
Time [min]
50
60
70
80
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Comparison between GA and DBM
results
Optimization outputs
DBM
GA 1
4
3
2.41
(14.8%)
2.48
(12.4%)
1.13
0.85
65
68
Max SOC [/]
0.79
0.88
Min SOC [/]
0.65
0.58
HC emissions 2 (g/km)
0.025
0.018
NEG
Fuel consumption [kg] and
% saving (*)
HC emissions 1 (g)
Average engine temperature [°C]
A further optimization analysis was run considering an increase in PV horizontal area
from 1.44 m2 to 3 m2. Such configuration upgrade results in a fuel consumption
reduction from 2.48 kg to 2.28 kg (19.4% saving).
(*) conventional vehicle fuel consumption = 2.83 Kg
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Outline
Introduction
HSV: models and results
Optimization of Management Strategies
The Prototype
Conclusions
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV Prototype
Vehicle
Length
Width
Height
Drive ratio
Electric Motor
Continuous Power
Peak Power
Batteries
Piaggio Porter
3.370 m
1.395 m
1.870 m
1:4.875
BRUSA MV 200 – 84 V
9 KW
15 KW
16 6V Modules Pb-Gel
Mass
Capacity
Photovoltaic Panels
Surface
Weight
Efficiency
520 Kg
180 Ah
Polycrystalline
1.44 m2
60 kg
0.13
Electric Generator
Diesel Yanmar S 6000
Power COP/LTP
Specific fuel cons.
Weight
5.67/6.92 kVA
272 g/kWh
120 kg
Overall weight (with driver)
Weight
1950 kg
A prototype of hybrid solar vehicle with
series structure has been developed at
the University of Salerno, within the EU
Leonardo Program “Energy Conversion
Systems and Their Environmental
Impact” (www.dimec.unisa.it/leonardo)
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
A research and educational project
Leonardo Program (I05/B/P/PP-154181)
Energy Conversion Systems and Their Environmental Impact
http://www.dimec.unisa.it/leonardo
Sponsored by ACS, Salerno (I), Lombardini (I), Saggese (I).
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
The web site
www.dimec.unisa.it/Leonardo
A multi-lingual web site
has been developed.
The site has more than
1000 visits per week
and is at the top
positions on Google.
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Participation to the FIA Alternative Energies Cup
race ECO-TARGA FLORIO (Palermo, Italy)
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Outline
Introduction
HSV: models and results
Optimization of Management Strategies
The Prototype
Conclusions
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
Conclusions
Hybrid Solar Vehicles can represent a valuable solution
for energy saving and environmental issues, but accurate
re-design and optimization of both vehicle and powertrain
with respect to HEV are required.
Economic feasibility could be achieved in a near future,
with realistic assumptions for component costs, fuel
price and PV panel efficiency.
Significant fuel savings can be obtained by proper ICE
management strategies. Thermal transient effects on
fuel consumption and HC emissions must be considered in
case of intermittent use.
The use of optimization techniques (GA, DBM) has allowed
to select the best management strategies, to be used as
benchmark for real-time implementable control.
Interdisciplinary research is needed, but also a
systematic dissemination of results and potentialities, in
order to remove the obstacles to the diffusion of such
vehicles.
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
On-going activities
Development and implementation of real-time
control strategies and comparison with benchmark
solutions.
On road tests on the prototype to validate both
simulation results and control strategies.
Installation of an automated sun-tracking roof to
further enhance solar energy contribution.
INTERNATIONAL CONFERENCE ON AUTOMOTIVE TECHNOLOGY ICAT06, NOVEMBER 17, 2006, ISTANBUL
Hybrid Solar Vehicles: Perspectives, Problems, Management Strategies
HSV – An artistic point of view
Thank you for your kind attention