Energy management of a battery storage and D-STATCOM integrated power system using fractional order sliding mode control

Abstract

At present, the power system is more inclined towards disturbances, such as voltage variations and unbalanced load conditions, due to the grid's complexity and load growth. These challenges emphasize the integration of the compensating devices, such as battery storage (BS) and D-STATCOMs. In this regard, this current paper exhibits a novel energy management system (EMS) of a combined BS and D-STATCOM to compensate the power system during disturbances. The EMS is based on a fractional order sliding mode control (FOSMC) to drive the voltage source converters (VSCs) such that the active power is independently absorbed/injected by the BS, whereas the reactive power is independently absorbed/injected by the D-STATCOM depending upon the disturbance situation. FOSMC is a robust non-linear controller in which the Riemann-Liouville (RL) function is employed to design the sliding surface and the exponential reaching law is used to minimize the chattering phenomenon. The stability of the FOSMC in the proposed EMS is proved using the Lyapunov candidate function. In order to validate the performance of the proposed EMS, a model of a 400 V, 180 kVA radial distributor along with a BS and D-STATCOM is simulated in MATLAB/Simulink environment in two test cases. The results prove that the proposed EMS with FOMSC effectively compensates the power system under voltage variations and unbalanced load conditions with rapid tracking, fast convergence and upright damping. Furthermore, the results have been compared with the classical proportional integral (PI) control and fixed frequency SMC (FFSMC), and they demonstrate the superiority of the proposed EMS with FOSMC in power system applications.