A Comparison of Two-Stage Inverter and Quasi-Z-Source Inverter for Hybrid Energy Storage Applications

Batteries are the primary energy sources in many applications such as Electrical Vehicles (EV) and storage facilities. It is known that batteries are high-energy-density and low-power density devices. The hybridization of the storage systems can potentially overcome the batteries drawback, using a high-power-density device such as ultracapacitors (UCs). Many researchers have been focusing on power converters optimal structure for the Hybrid Energy Storage System (HESS). Among them, the Quasi-Z-Source Inverter (qZSI) is a promising solution to simplify the integration of batteries and UCs. In this paper, a comparison of the conventional inverter and the qZSI in HESS is carried out in terms of voltage stresses on the switches, voltage requirements for batteries and UCs, passive component sizing, output voltage THD and system efficiency.