Analysis and design of a novel high efficiency converter for hybrid application

Ultracapacitors are electrochemical energy storage/conversion systems of high power applied in hybrid electric vehicles beside batteries. Since the voltage level of the DC bus differs from the ultracapacitor, it is necessary to utilize an interface circuit to balance (increase or decrease) the voltage between the DC bus and ultracapacitor. This paper presents a new buck-and-boost ultracapacitor interface circuit used between ultracapacitors and DC bus (batteries) in the hybrid electric vehicles. The operation of the proposed circuit is introduced and experimental results confirm the theoretical analysis.