A novel control strategy of super capacitor-battery energy storage system

Storages are usually used to absorb the fluctuation power produced by distributed generators such as wind turbine (WT) and photovoltaic (PV). The SC-battery hybrid energy storage system (HESS) has attracted more and more attention because of the advantages of high power density and high energy density. In this paper, a typical ac power grid is presented which consists of WT, PV, super capacitor (SC) and battery. A novel cooperative control strategy for HESS is proposed to control the SC to rapidly absorb or release power and the battery to exchange slowly fluctuating power. It is proved that the proposed control strategy can prevent the SC from saturation and low voltage, which can make full use of SC and battery. Finally, a wind-solar power example is proposed to verify the effectiveness and correctness of the control strategy. The results show that the control strategy can make SC and battery run normally and restrain the fluctuation power.