Integral sliding mode control of four-leg DSTATCOM coupled with SMES unit

In this paper, an integral sliding mode control is proposed to control a four-leg Distributed Static Compensator (DSTATCOM) system coupled to a superconducting magnetic energy storage (SMES) unit. The proposed SMES based DSTATCOM (SDTATCOM-SMES) is connected to a three-phase four-wire distribution system feeding a set of balanced and unbalanced loads. The control system is designed to compensate the needed reactive power in order to regulate the (point of common coupling) PCC voltage level under different operation cases. In addition, compensate for negative- and zero-sequences components to ensure a balanced current and suppresses the neutral current in the fourth wire of distribution system in case of feeding unbalanced loads. Finally, a computer simulation is performed to validate the efficiency of the proposed strategy. A comparison with the conventional PI controller shows the superiority of sliding mode controller in term of high tracking accuracy, fast dynamic response and good robustness.