Finite-time Adaptive Sliding Mode Control of DC Microgrids with Constant Power Load

Due to recent advances in power electronic systems, direct current (DC) microgrid (MG) topology is considered as a promising solution to unite pollution-free renewable energy sources and DC loads. This paper investigates the issue of finite-time robust adaptive stability and tracking issue of a nonlinear direct current (DC) microgrid (MG) comprising a buck converter, linear resistive loads, and nonlinear constant power loads (CPLs). The developed approach is based on a sliding mode controller (SMC) and a nonlinear and nonsingular sliding surface. It is proved that the tracking error converges to zero in a finite-time in the presence of matched disturbance input and uncertainties. The novel controller manipulates the buck converter of the source side to regulate the DC bus voltage by counteracting the destabilizing effect of CPLs and disturbances. Further, the finite value of the convergence time is presented and the effects of the SMC parameter on the stability and transient performance are evaluated. Lastly, numerical simulations are conducted to illustrate the merits of the developed control approach in the viewpoints of fast reference tracking and robust stability.