A Parallel Bidirectional DC/DC Converter Topology for Energy Storage Systems in Wind Applications

Integration of an energy storage system (ESS) improves wind energy system performance. Due to its simplicity and robustness, the bidirectional IGBT buck/boost converter is often selected to interface the supercapacitor or battery ESS with the DC voltage bus. For conventional single-unit topologies, the converter has discontinuous current on the high voltage side and other limitations. This paper proposes a parallel structure of bidirectional buck/boost converters and its power-tracking control scheme for wind ESS applications. The converter performance is studied and compared to the single-unit topologies. The proposed converter has smooth currents and fast dynamics which allow reduction of converter switching frequency and DC filtering capacitor. Other advantages of this topology include reduction of switching losses, improved reliability and flexibility.