Research on VRB-SC for Smooth Nine Switch Converter PMSG Wind Power Fluctuation

Abstract

The back-to-back converters have been used in the typical direct drive wind power system, but the number of switching devices required is large, so the nine switch converter (NSC) is proposed to replace it. The voltage utilization is improved by injecting a zero sequence component into the modulated wave. High efficiency energy storage technology is an effective way to improve the absorption capacity of wind power. The hybrid energy storage system (HESS) adopts vanadium redox battery (VRB)-super capacitor (SC) structure. Control strategy based on the first-order lowpass filter, coordinates and optimizes the charging and discharging processes of each energy storage unit. The results show that the NSC-PMSG wind power system can achieve the control performance of the traditional direct drive wind power system, and the use of SC can effectively reduce the number of charging and discharging cycles of the battery system, thus extending the service life of the battery.