T03 Energy-storage
and applications with supercapacitors
A. Rufer, Professor, LEI-EPFL, CH-1015 Lausanne
R. Gallay, Dir. R&D, Montena Component SA, CH-1728 Rossens
P. Barrade, Lecturer/Researcher, LEI-EPFL, CH-1015 Lausanne
Half day (9 a.m. to 12 a.m.)
Location: Semriach
including sightseeing: Lur-Grotte or Stübing (old farming
houses open air museum)
Abstract
Supercapacitors represent one of the newest innovations in the
field of electrical energy storage, and are subject of several
developments in the industry for many different and new
applications. The tutorial will give first some basic knowledge
on the components themselves and comparatively on the physical
mechanism of the Electro-Chemical Double Layer (ECDL) capacitors.
Then, some aspects on the external behaviour will be presented,
together with typical needed apparatus and arrangements for the
design of large storage tanks. A third part will be presented,
including typical applications and associated power electronic
solutions for the energy management and for the interface.
Who should attend
The tutorial with its mixed content is dedicated as well to
developing engineers in industry as for research engineers at
university level who are looking for basic information on the new
technology
Targets
The interest of that tutorial is that the presentation of
supercapacitors will be made under 3 different points of view :
-
- From the main principles to the component : the
physics of supercapacitors,
- From the component to the supercapacitors bank :
models of supercapacitors, the component from the
power electronics point of view,
- From the supercapacitors bank to the application
: thanks to appropriate power converters, a
supercapacitors bank can be used as a main energy
storage device, or as an energy buffer bank to
minimise power constraints on a supply.
Schedule of the tutorial
09:00- 10:00 : Basics on supercapacitors (Dr. Roland
Gallay, montena components SA Rossens) :
-
- Physical basic principle of double-layers
phenomenon : Supercapacitors, also known as
electrochemical double-layers capacitors, are new
passive components which are now available for
use in power electronic applications. They have a
huge capacitance, typically 1000 Farad, which is
much larger than conventional capacitors. They
show performances which are lying between those
of batteries and capacitors. The capacitance is
due to the accumulation of electronic and ionic
charges at the interface between the electrodes
and the electrolyte.
- Supercapacitor technology description :
the supercapacitor construction has to take into
account several important requirements as low
series resistance for high current applications,
high parallel resistance for reduced self
discharge, etc. These performances are obtained
by winding electrodes together with separators,
drying them and impregnating them with an
electrolyte.
- Component properties and behaviour : the
use of supercapacitors requires a good knowledge
of their voltage, current, temperature, cycling
and aging dependencies. The ohmic losses are a
key factor which determines the size of the
storage device.
- Modelization : the non-linearity of the
voltage-current characteristic gives rise to new
capacitance concepts. A model has been developed
in order to be able to determine the current and
power amplitude, and the capacitor energy
content.
10:00- 10:45 : External behaviour and environment (Dr
Philippe Barrade, EPFL, Lausanne) :
-
- Modeling supercapacitors : an equivalent
electrical model of a supercapacitor will be
defined, regarding the previous model that has
been presented. Illustration of what that model
offers will be done by the use of a simulation
tool on which such a model has been implemented.
- Sizing of a supercapacitors bank :
depending on various energy and power
specifications, it will be explained how to
design a supercapacitors bank (voltage levels,
current rate, and available energy).
- Solutions for charge-equalizer of a series
connection : Because a series connection of
supercapacitors is needed, solutions have to be
proposed to have an equalisation of all the
voltages to avoid any over-voltage on the
components, and to be sure that it is possible to
store in a Scaps bank the maximum amount of
energy.
- Macro-models for simulation : The time
order for loading energy in supercapacitors is
near of 10sec. But the switching frequency of the
associated power converters is more than the
kilohertz. For that reason, a small simulation
step for a simulator have to be adjust, with the
consequence of a long simulation time. To avoid
that, average models will be proposed,
11:00- 12:00 : Applications and converters (Prof. A. Rufer
EPFL, Lausanne) :
-
- Power-electronic circuits and converters for
supercapacitive storage : Compared to
batteries, supercapacitors can not be used alone,
and have to be associated with power converters.
Various topologies will be proposed (classical
boost plus buck converters, and a new
soft-commutated converter with AC link at medium
frequency)
- Application examples of supercapacitive
storage
-
- Complementary storage with batteries :
here the functions are clearly
dissociated. The batteries have to
provide the energy, and the Scaps have to
provide the instantaneous power needed by
as load
- Active load compensation for weak
distribution in traction : this
application illustrates the way
supercapacitors can be used as energy
buffer bank to minimise the constraints
on a power supply.
- Sequencial distribution with double
storage, load equaliser for elevators :
this last example illustrates the way
supercapacitors can be used both as main
energy source and as energy buffer bank.
Biography of Prof. A. Rufer
Alfred Rufer was born in 1951 in St. Immier,
Switzerland. He received a Master’s degree form the Swiss
Federal Institute of Technology in Lausanne (EPFL), Switzerland,
in 1976. In 1978, he joined ABB, Turgi, Switzerland, where he
worked in the fields of power electronics and control such as
high-power variable frequency converters for drives. In 1985, he
was a Group leader for power electronics development at ABB. In
1993 he became Assistant Professor at EPFL. Since 1996, he has
bee Professor and Head of the Industrial Electronics Laboratory
at EPFL. He has several patents and is the author of publications
on modulation and control methods and power electronics.
Biography of Dr. R. Gallay
Roland Gallay was born in 1958 in Fribourg,
Switzerland. He received a Master’s degree from the Swiss
Federal Institute of Technology in Lausanne (EPFL), Switzerland,
in 1982. He obtained a PhD degree of the EPFL in the domain of
solid state physics. In 1990 he joined montena components, a
capacitor manufacturer, where he is managing the R&D
department. He has been involved in the development of high
voltage capacitors and power capacitors for traction
applications. From 1995 to 98, he has managed the power capacitor
business unit. Since 1998 its main activity is the supercapacitor
development. Since 1987 he is lecturer in the electrical
department of the EPFL.
Biography of Dr. P. Barrade
Philippe Barrade was born in 1968 in Cahors, France. He
received a Master’s degree from the Paul Sabatier University
in Toulouse, France, in1991. He obtained a PhD degree in
Electrical engineering at the Polytechnic National Institute of
Toulouse, France, in 1997. In 1998, he joined SAFT, Tours,
France, where he worked in the field of power electronics, such
as uninterruptible power supplies. In 1999, he became first
assistant, lecturer at EPFL, in the Industrial Electronics
Laboratory. His main research field concerns the energy storage
and management by means of supercapacitors.
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