Optimal control of state-of-charge of superconducting magnetic energy storage for wind power system

The optimal control of state-of-charge (SOC) for superconducting magnetic energy storage (SMES), which is used to smooth power fluctuations from wind turbine, is essential to improve its technical and economical performance. Without an efficient control strategy, the SMES may go to the state of over-charge or deep-discharge, which will pose a significant effect on its service life and its technical performance. In this study, combined with wind forecasting technology and real-time monitoring of SOC for the SMES, a double fuzzy logic control strategy is proposed that is applied to regulate SOC of SMES with the purpose of not only effectively smoothing the power fluctuations of wind turbine, but also preventing the SMES from occurring of the state of over-charge/deep-discharge and adjusting it to the appropriate SOC. The effectiveness of the proposed control strategy is verified by the simulation results.