A control strategy of smoothing wind power output based on variable terms of slip average filter

According to the randomness and volatility of the wind power output, taking into account the constraints such as wind power fluctuations and current state of charge (SOC) of battery energy storage system (BESS), a smoothing control strategy based on variable number of terms of slip average filter is proposed. This method can regulate the number of terms of slip average filter, according to wind power fluctuations and the SOC value of BESS, thus the target of the output power is changed, and thereby the SOC of BESS is stabilized in a certain range. At the same time, over-charging/over-discharging of the BESS is avoided, and the smoothness of output power of wind power and energy storage system is improved. Simulation results show that the proposed method in this paper can make the SOC of the BESS stabilized in a limit range, while wind power fluctuation rate within 20 min is controlled below 10%, the accumulation of power fluctuations within 20 min is reduced by 20.5% than ordinary slip average filter strategy, and therefore the smoothness of wind power output is improved effectively. Research results provide a reference to the application of BESS.