Download MODULAR INTEGRATED ENERGY STORAGE DEVICE AND

MODULAR INTEGRATED ENERGY STORAGE DEVICE AND
POWER CONVERTER BASED ON SUPERCAPACITORS
Background
With the increasing energy demand and emergence of renewable energy, large amounts of
energy must be stored and later very quickly restored, generating high power. A promising
approach is to use supercapacitor banks which have a shorter reaction time and larger power
output than batteries. To reach a high enough voltage, supercapacitors need to be connected in
series. The problem is that since the supercapacitors all have a slightly different capacitance, they
cannot be simultaneously fully charged and the available storage maximized, unless an
equilibrating circuit is used (at the expense of additional losses). Special care must also be taken
to avoid overvoltage on individual capacitors. Moreover, supercapacitor banks require a power
converter to be used alongside, which increases the size of the system and causes
electromagnetic interference (EMI) due to high frequency switching.
Technology
This new design integrates the storage unit and the power converter in the same compact modular
device made of a number of basic cells connected in series comprising only low cost, low voltage
components. The basic cell contains two supercapacitors as well as switches protecting against
overvoltage by supplying an alternative current path and allowing to make use of the full storage
capacity by controlling the voltage of each capacitor individually. The switches are controlled by a
programmable microcontroller capable of performing any desired conversion (DC/DC, AC/DC,
DC/AC, AC/AC) by putting a variable number of cells in series. The innovative integrated power
converter hence does not rely on high frequency switching which eliminates the EMI problem.
Application
The device could be applied for braking energy recovery in trains, subways, cars, motorcycles,
bicycles... In addition to providing energy storage, the device replaces standard standalone power
converters with the advantage that the storing device provides short-term autonomy in case of
power outage. For renewable energy, it could also be useful to level the power output of wind
turbines and solar panels in which the energy production and consumption are quite irregular.
Competitive Advantages
One compact device for both energy storage and power conversion
Maximized stored energy by controlling the voltage on each capacitor
Low frequency operation thus no electromagnetic interference
Suitable for any type of power conversion (AC/DC, AC/AC, DC/AC or DC/DC)
Quick and easy to repair modular arrangement of low cost, low voltage components
Patent
US Provisional Patent Application – « MODULAR ENERGY STORAGE DEVICE »
Next Steps
As a proof of concept, a few cells have been assembled. The next step is to make the device more
compact and devise a robust matrix controller. The technology is available for licensing.
Contact
Morgan Guitton, Jr. Eng.
Project Manager, Business Development
Sciences and Engineering
Univalor
+1 (514) 340-3243 ext. 4231
[email protected]
Frédéric Sirois, Ph.D.
Professor
Department of Electrical Engineering
Polytechnique Montreal
+1 (514) 340-4711 ext. 3607
[email protected]