Energy management and control optimization of marine current power system based on hybrid energy storage system

Due to climate change and the risk of depletion of traditional fossil energy, developing renewable energy has become a common consensus of the international community. Marine current energy is regarded as the most desirable form of ocean energy due to its high density and strong predictability. However, the variations of marine current velocity caused by the swell effect lead to the fluctuation of marine current power. In this paper, an energy management strategy based on a Two-Stage Fuzzy Logical Controller (TSFLC) is proposed to redistribute the marine current power and abate marine current power fluctuation. The hybrid energy storage system composed of vanadium redox flow battery and supercapacitor banks (SCB) is applied to smooth the marine current power and improve the power quality according to the energy management strategy. Meanwhile, TSFLC can reduce the rated capacity of SCB, avoid the overcharge and over-discharge of the SCB, and keep the state of charge of SCB within a reasonable range. Furthermore, for better tracking performance and smaller steady-state error, particle swarm optimization is applied to tune the parameters of the PI controller in the SCB control loop. A simulation model of a 3-MW marine current power system is built to verify the effectiveness of the control strategy.