A Tri-State Bidirectional Buck-Boost Converter for a Battery/Supercapacitor Hybrid Energy Storage System in Electric Vehicle Applications

Hybrid Energy Storage System (HESS) are commonly used when a combination of features and advantages from different energy storage devices are needed. Due to their characteristics, when batteries and Supercapacitors (SC) are implemented in HESS they become a good option for Electric Vehicle (EV) applications. This paper presents a bidirectional DC-DC converter as an interface between the battery and the SC, this will allow the control of the power flow. A tri-state operation for a bidirectional Buck-Boost converter is proposed in order to improve the performance of the control and reduce losses in the HESS.