The role of ultracapacitors in an energy storage unit for vehicle power management

This paper extends a design methodology for a combined battery-ultracapacitor energy storage unit (BU-ESU) for vehicle power management into two areas. First, the model of the half-bridge converter replaces the generic models of the dc/dc converters used in the BU-ESU. This model is capable of determining the electric stresses present on the active and passive components during the operation of the vehicle. Second, an improved BU-ESU control strategy applicable to all operating conditions of the vehicle is determined. This control strategy is used to resize the BU-ESU. Finally, the vehicle fuel consumptions achieved when using this newly resized BU-ESU are compared using ADVISOR simulation results with those obtained for the BU-ESU designed in R.M. Schupbach et al. (June 2003).