Modelling and study of a solar car
with embedded photovoltaic array and Li-ion storage
S.Astier, R.Saïsset, X.Roboam
Laboratoire d’Electrotechnique et d’Electronique Industrielle, LEEI, UMR CNRS/INPT 5828
2 rue Camichel - 31071 Toulouse cedex 7 - France
Phone: (+33) 5 61 58 82 08, Fax: (+33) 5 61 63 88 75, E-mail: name@leei.enseeiht.fr
Keywords: bond graph, solar vehicle, photovoltaic, Li-
Ion, model, energy management.
Abstract – In this paper, an original model of the
whole system of a solar car is described. Based on
Bond Graph, it involves the models of the vehicle
dynamics, the permanent magnet DC Brushless wheel
motor, the embedded solar array, the Li-Ion storage
and the static converters used for energy management.
It is shown how it enables to choose the right array
architecture taking account of the actual body shape
and sun position with respect to the optimal global
performances of the car over a day. It is also shown
how it can be used to compare various energy
management, a very general problem concerning
many autonomous energy systems developed for
various applications today.
I. INTRODUCTION
Except geothermal or nuclear energy sources, the solar
energy is at the origin of all other energy sources
exploited by life and mankind; so it has a symbolic
character with the aim of the "sustainable development".
On another hand modern transport systems are
synonymous of liberty, but also greenhouse effect. Then,
solar vehicles called "Sunracers", which can cross the
Australian continent at significant average speeds, up to
90 km/h, using exclusively the electric energy drawn form
their embedded photovoltaic generator are symbolic of the
dream of conciliating our moving needs with ecology.
But, such a challenge is only achieved with very high
performance vehicles, specially optimised in terms of
energy saving. Such a system involves components and
architecture very representative of many other ones
dealing with the general problem of the optimal design of
high efficiency autonomous systems. Indeed, Electric
power systems are more and more complex and their
design requires a global optimisation which is based on a
so called "system approach", relying on the development
of efficient local and global models. Beside an intrinsic
great interest for searchers and students, this is a reason
why we have designed and studied such a sunracer in our
university. It is called "SOLELHADA" and participated in
the "2001 Solar Odyssey", crossing the Australia on 3010
km in 50 hours at an average speed of 60 km/h, only using
47 kWh exclusively drawn from its PV generator, the
equivalent of only 6 litres of fuel. In this paper, an original
model of the whole system of this solar car is described.
Based on Bond Graph modelling, it involves the models
of the vehicle dynamics, the permanent magnet DC
Brushless wheel motor, the embedded solar array, the Li-
Ion storage and the static converters used for energy
management. It is shown how it was used to choose the
right array architecture taking account of the actual body
complex curved shape and of the sun position with respect
to the optimal global performances of the car over a day.
It is also shown how it can be used to compare various
energy management, a very general problem for
autonomous energy systems developed in many
applications today. Performing such a study is worth for
many other applications dealing with architecture, energy
management, embedded storage and energy production, a
major topic of interest in our laboratory and in the general
context of sustainable development.
II. THE DESIGNED SOLAR CAR : “SOLELHADA”
Fig.1: SOLELHADA during the WSC 2001 in Australia and its system
architecture
A. About the "Sunracers" and the World Solar Challenge
Sunracers are very special autonomous electric cars which
only draw their energy from the sun through an embedded
generator and compete every two years during the
prestigious World Solar Challenge, racing through
.....