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Electric sources are widely used in order to design cleaner vehicles
(batteries, fuel cell systems, ultra-capacitors, etc.). However, numerous
electrified vehicles are produced in small series and the design of a specific
energy source for a given vehicle is both time consuming and expensive.
In this way, Modular Energy Systems (MES) are useful to integrate
generic sources into a vehicle. The aim of MES is to split the power and/or the
energy storage between several standardized modules and so, they lead to
several economical and technical benefits:
- Economy
of scale. Especially for niche markets, MES allow to use the same energy system
into several different power vehicles. For instance, we can built a 20kW fuel
cell vehicle by using two 10kW modules and a 50kW fuel cell vehicle by using
five 10 kW modules. In both cases, the same module is used and the production
volumes can be increased
- Efficiency improvement. With a proper architecture, the features of MES
offer more degrees of freedom, which provides several power distribution
possibilities in order to achieve superior efficiency for varying loads
- Reliability and durability. MES is capable of operating in a degraded mode, if one or more sources break
down due to malfunction. With regard to durability, it is worth mentioning that
the components of a MES are normally run within their efficient zones to
provide the demanded power (by using the flexible power distribution feature).
Moreover, in case of low power requirements, only one or few elementary modules
are used and so, the not used modules does not degrade. This way of operation
prolongs the lifetime of the system
- Flexible architecture (mass distribution). The center of gravity
location in longitudinal, lateral and vertical orientations influences the
stability of the vehicle in normal and maneuvering modes of operation. MES
allow to place the modules in different locations of the vehicle and so, to
adjust the center of gravity
These features make MES suitable for different modes of transportation
such as rail, road, maritime, and air. For instance, the powertrain of LF-LRV
tramway designed by Chinese manufacturer of Tangshan Railway Vehicle Co. Ltd is
composed of two PEM fuel cells, two battery packs, and two ultra-capacitor
modules.
Daimler Citaro fuel cell bus is built on two fuel cell modules already
used into the Mercedes B-Class car. Multi genset systems have been common in
maritime applications for many years. Today, several fuel cell and battery
modules are integrated in order to design a real hybrid ship with lower
consumption and GHG emissions.
So, modular energy systems are both of a way to speed up the launch of
greener vehicles and an amazing research opportunity in many electric
engineering topics as energy management strategy, diagnosis, prognostic and
fault tolerant control, sizing of systems, … and so on! |
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