Modelling and controlling of vanadium redox flow battery to smooth wind power fluctuations

High randomicity of wind power brings a big problem to power grids.Thus,attenuation of wind power fluctuation through energy storage systems becomes more and more important.In this study,Vanadium Redox Flow Battery(VRFB) is proposed as the storage system to smooth wind power fluctuation.Based on an equivalent circuit of electric-chemical AC impedance of VRFB,the change law of main parameters in the equivalent circuit is analyzed and simplified,and the mathematical model is analyzed and established to show charge and discharge characteristics of VRFB.A control scheme of VRFB is proposed based on power decoupling method of an AC/DC converter to smooth wind power.Taking the measured data in a practical wind farm and 1.5 MW double-feed motor as examples,the effectiveness and feasibility of the control strategy of VRFB are verified using PSCAD /EMTDC simulation software package.