A new battery energy storage system control method based on SOC and variable filter time constant

Because of large fluctuations and strong randomness of active power generated by renewable energy resources, taking into account the constraints such as battery life cycle, a new battery energy storage system control method based on real-time state-of-charge and variable filter time constant is presented. This method could compensate the fluctuation composition of a particular frequency band of power. At the same time, filter time constant is adjusted in order to stabilize the value of SOC in a certain range, and over-charging and over-discharging of the battery is avoided. A photovoltaic (PV) and battery hybrid system modeled by PSCAD is tested to verify the validity of this method.