A sliding mode controller-based STATCOM for voltage profile improvement of micro-grids

Abstract

PurposeThe purpose of this paper is to evaluate the suitability and robustness of sliding mode controller (SMC) for maintaining flat voltage profile at the load bus of two different micro-grid systems using STATCOM.Design/methodology/approachTwo micro-grid systems are dynamically modelled and simulated using MATLAB/Simulink. The first micro-grid has a single diesel engine-driven synchronous generator. The second micro-grid has one diesel engine-driven synchronous generator and a doubly fed induction generator-based wind energy conversion system. The STATCOM is connected to the load bus in both the micro-grids. SMC is used for the control of STATCOM for voltage profile improvement of micro-grid. The performance of SMC-based STATCOM is analysed and compared with the performance of conventional PI controller-based STATCOM.FindingsThe SMCs are more suited for STATCOM control as these are more immune to load disturbances even with the presence of wind energy generators. The voltage deviations and the steady state errors in voltage are less with SMC. Although SMC introduces a bit of steady state error in the dc link voltage of the STATCOM, it is much less than the settling limit of 2 per cent, which is quite acceptable. SMC proves to be better than conventional PI controllers in both the proposed models of micro-grid.Originality/valueDesign of a robust first-order SMC for a STATCOM is used for voltage profile improvement in two different micro-grid systems.