Control and Operation of Multifunctional DSTATCOM with Battery-Supercapacitor Energy Storage System

The conventional multifunctional DSTATCOM has a compensation limitation as it cannot compensate deep voltage sag and swell. To overcome this, a new configuration of multifunctional DSTATCOM is proposed in this paper. The proposed system consists of a voltage source inverter (VSI) and battery-supercapacitor energy storage system which is connected to the DC link through DC/DC converters. The proposed multifunctional DSTATCOM has all the advantages of a conventional multifunctional DSTATCOM. Moreover, it can mitigate deep voltage sag, swell and interruption. The battery-supercapacitor energy storage system delivers power to the load during deep voltage sag, swell and interruption, known as uninterruptible power supply mode (UPS). Battery delivers average load power during UPS mode, while grid is disconnected from the system and supercapacitor delivers all the load fluctuating power. The supercapacitor also delivers the fluctuating power during normal operation. This helps to improve the DC link voltage dynamics during sudden changes in source voltage and load power. The performance of the proposed hybrid DSTATCOM with battery-supercapacitor energy storage system has been verified through simulation studies.