Unified control of smoothing out wind power fluctuations and active power filtering by an energy storage system

It is becoming a hot spot to utilize energy storage system(ESS) to smooth out the wind power fluctuations. However, it brings some problems such as the high cost of ESS and the low utilization of the power converter system(PCS) for weather changing. In order to enhance the cost performance, the paper proposes a new control strategy which combines the smoothing and filtering functions of ESS based on the similar circuit structure between the energy storage PCS and the active power filter(APF). Firstly, the principle of unified control is analysed in detail and the realization of unified control is proposed. Then, the paper uses an amplitude-clamping algorithm (ACA) to make full use of the surplus capacity of the PCS in security. At the end, the simulation results verify the effect of the ESS with smoothing and filtering functions.