Fwd: [LINK] ultracapacitors +

[Geoffrey Ramadan]

I found the following on the respected Institute of Electrical and 
Electronics Engineers (IEEE) web site (www.ieee.org) on 
"ultracapaictors" that might be of interest.

Batteries and Ultracapacitors for Electric, Hybrid, and Fuel Cell Vehicles
Burke, A. F.
Proceedings of the IEEE
Volume 95, Issue 4, April 2007 Page(s):806 - 820
Digital Object Identifier 10.1109/JPROC.2007.892490
Summary:The application of batteries and ultracapacitors in electric 
energy storage units for battery powered (EV) and charge sustaining and 
plug-in hybrid-electric (HEV and PHEV) vehicles have been studied in 
detail. The use of IC engines and hydrogen fuel cells as the primary 
energy converters for the hybrid vehicles was considered. The study 
focused on the use of lithium-ion batteries and carbon/carbon 
ultracapacitors as the energy storage technologies most likely to be 
used in future vehicles. The key findings of the study are as follows. 
1) The energy density and power density characteristics of both battery 
and ultracapacitor technologies are sufficient for the design of 
attractive EVs, HEVs, and PHEVs. 2) Charge sustaining, engine powered 
hybrid-electric vehicles (HEVs) can be designed using either batteries 
or ultracapacitors with fuel economy improvements of 50% and greater. 3) 
Plug-in hybrids (PHEVs) can be designed with effective all-electric 
ranges of 30-60 km using lithium-ion batteries that are relatively 
small. The effective fuel economy of the PHEVs can be very high (greater 
than 100 mpg) for long daily driving ranges (80-150 km) resulting in a 
large fraction (greater than 75%) of the energy to power the vehicle 
being grid electricity. 4) Mild hybrid-electric vehicles (MHEVs) can be 
designed using ultracapacitors having an energy storage capacity of 
75-150 Wh. The fuel economy improvement with the ultracapacitors is 
10%-15% higher than with the same weight of batteries due to the higher 
efficiency of the ultracapacitors and more efficient engine operation. 
5) Hybrid-electric vehicles powered by hydrogen fuel cells can use 
either batteries or ultracapacitors for energy storage. Simulation 
results indicate the equivalent fuel economy of the fuel cell powered 
vehicles is 2-3 times higher than that of a gasoline fueled IC vehicle 
of the same weight and road load. Compared to an engine-powered HEV, the 
equivalent fuel economy of the hydrogen fuel cell vehicle wou- ld be 
1.66-2.0 times higher


Ultracapacitor-Based Auxiliary Energy System for an Electric Vehicle: 
Implementation and Evaluation
Ortuzar, M. Moreno, J. Dixon, J.
This paper appears in: Industrial Electronics, IEEE Transactions on
Publication Date: Aug. 2007
Volume: 54 , Issue: 4
On page(s): 2147 - 2156
Number of Pages: 2147 - 2156
ISSN: 0278-0046
Digital Object Identifier: 10.1109/TIE.2007.894713
Posted online: 2007-07-16 13:21:06.0
Abstract
In the search for better efficiency, an auxiliary energy system (AES) 
for electric vehicles (EVs) was designed, implemented, and tested. The 
system, which is composed of an ultracapacitor bank and a buck–boost 
converter, was installed in an EV, which is powered by a lead-acid 
battery pack and a 54-kW brushless dc motor. Two control strategies 
where developed: one based on heuristics and the other based on an 
optimization model using neural networks. These strategies were 
translated to algorithms and implemented in a digital signal processor, 
and their performance was evaluated in urban driving. The results were 
incorporated to an economic evaluation of the system, which shows that 
the reduction in costs would only justify the inclusion of this type of 
system in a lead-acid battery-powered vehicle if the battery life is 
extended by 50% or more, which is unlikely. The same results were 
extrapolated to a case in which the lead-acid batteries are replaced by 
a fuel cell. In this case, the costs of different power support systems 
were evaluated, such as ultracapacitors and high-specific-power 
lithium-based batteries. The results showed a significant cost reduction 
when AES configurations are included in contrast to a system powered by 
fuel cells only. Also, the cost reduction was higher when using 
ultracapacitors for this purpose.

Reg
Geoffrey Ramadan B.E.(Elec)
Chairman, Automatic Data Capture Association (www.adca.com.au)
and
Managing Director, Unique Micro Design (www.umd.com.au)