Dg With Reduced Upfc In Micro Grids Using Lcl Plus Nonlinear Optimal Control For Stability Improvement

Abstract

 This research presents a new method to improve the ability of small-scale microgrids to maintain stability during temporary disturbances. This is achieved by combining a simplified Unified Power Flow Controller (UPFC) configuration with a low-pass filter (LCL) in the Distributed Generation (DG) unit. The DG unit consists of a Photovoltaic (PV) system that is linked to the grid via a dc-dc buck converter and inverter. The dc-dc converter ensures a consistent output voltage that is linked to the inverter, which produces the necessary ac voltage to power the grid. The downsized Unified Power Flow Controller (UPFC) with a Low Capacitance-Inductance (LCL) filter utilizes the Direct Current (DC) connection of the Distributed Generation (DG) unit to generate an appropriate series voltage. This voltage is then injected into the power line to enhance transient stability. In order to get the highest level of system stability while minimizing expenses, a nonlinear discrete-time Hamilton-Jacobi-Bellman (HJB) optimal control approach is used. The control strategy is specifically developed to optimize the functioning of the microgrid, with the primary goal of decreasing the total cost associated with stability improvement. The cost function is estimated by using a Neural Network that utilizes the weighted residual approach. The simulation results confirm the efficacy of the suggested model and control method. The integration of the DG unit, LCL, and UPFC architecture exhibits exceptional efficacy in attenuating oscillations within the system. This study adds to the progress in comprehending and using decreased UPFC structures in microgrid setups, presenting a feasible approach to achieve improved stability and dependability in distributed power systems.