Distributed secondary voltage control of islanded AC microgrids: A comparative study

This paper proposes a distributed secondary voltage control (DSVC) scheme of DG based islanded AC microgrids employing cooperative control design. The controller design has been further strengthened by introducing a bilayered adaptive control formulation. The centralized control scheme for inverter-based DGs in an islanded microgrid poses significant challenges in terms of voltage control, connectivity issues among all DGs and handling contaminated signals of the DG units under influence of unwanted signals i.e. noise and disturbances. The objective here is to design an optimal control input employing linear quadratic regulator (LQR) principle in cooperative and adaptive control formulation. An exhaustive comparative analysis driven by an exhaustive Matlab simulation has been done in order to demonstrate the effect of Algebraic Riccati Equation (ARE) parameters in the proposed cooperative and adaptive control algorithm to specify the variations in time domain specifications of the microgrid voltage response. Simulation analysis has been done to check the effectiveness of the adaptive controller over the cooperative design of the microgrid controller where DGs are subjected to variable frequency disturbance (VFD).