Design of battery and ultracapacitor multiple energy storage in hybrid electric vehicle

Abstract

Combination of battery and ultracapacitor as energy storage of hybrid electric vehicles is considered a good way to improve overall vehicle efficiency and battery life. Coordinated power distribution and bi-directional DCDC converter control are challenges. Method to determine distribution of ultracapacitor and battery is proposed based on a specific hybrid electric bus. A bi-directional DCDC converter is interface of two energy storage to control power flow. Metrics of converter are determined from vehicle simulation. To downsize the converter and get high efficiency, bi-directional DCDC converter operates under complementary DCM condition and soft-switching.