| Abstract |
In EV motor drives, battery load leveling by means of ultracapacitors is one attractive approach to improve
the battery life as well as vehicle driving range. Ultracapacitors have high power density and, in order to
reduce the peak power requirement for the battery, they can be used to manage the bi-directional power flow
due to vehicle acceleration and deceleration.
The ultracapacitor tank is sized on the base of the load leveling requirement, which is dependent on the
driving cycle by which the vehicle is expected to operate.
In this paper three power converter arrangements which use an ultracapacitor tank for battery load leveling
in EV motor drives are briefly reviewed. In the paper these converter arrangements are referred to as series
connection, cascade connection and parallel connection. The parallel connection is the converter
arrangement this paper is primarily concerned with. This configuration is accomplished by using a bidirectional
step-up/step-down converter to connect an ultracapacitor tank in parallel with the battery pack
and the motor drive dc link.
Simulations and test results achieved from a test campaign carried out by using an ultracapacitor tank rated
34.5 V and 31.3 F will be shown. |
