Soc Estimation of Vanadium Redox Flow Battery Based on OCV-DKF Algorithm

SOC(State of Charge) of VRB(Vanadium redox flow battery) is an important parameter for evaluating battery performance and estimating battery capacity, it is also a key basis for management and control of energy storage systems. In order to improve the estimation accuracy of SOC, a complex algorithm based on OCV(Open Circuit Voltage) and DKF(Double Kalman Filter) is proposed. After theoretical analysis and process derivation, a real-time charge/discharge simulation platform for 5kW/30 kWh VRB energy storage system was set up. The SOC was online estimated by using OCV-SOC curve and DKF algorithm. The results was compared with EKF(Extended Kalman Filter) algorithm and Ah method. Experiments show that the DKF algorithm has a better estimation effect and can stabilize the SOC estimation error within 1.5%.