Autonomous Power Sharing among Decentralized Inverters Using Modified Droop Control

The recent power grid integrates several renewable distributed generators (DGs) and energy storage devices. With multiple DGs integrated into the power grids, active and reactive power-sharing is essential for power management in both grid-connected and islanded operation modes. Compared to the grid-connected mode, maintaining the correct power-sharing ratio in the islanded mode or high renewable penetration power grid is more difficult due to the divergence of demand power and renewable generation. The energy storage system (ESS) then is used to minimize the adverse effect brought by the deviations of demand power and intermittency of DGs. Using the droop control in the grid-forming inverter can emulate the inertia of conventional generators to provide voltage-frequency regulation. The active power-sharing is achieved by using the different power-sharing coefficients for the grid-following inverter and grid-forming inverter. Accurate reactive power-sharing can be achieved by the integration of a virtual impedance network among inverters. However, autonomous power-sharing would accomplish only if the autonomous active-reactive power requirement is known. Therefore, we have determined the required real-reactive power of a particular node by integrating grid-forming inverter's instantaneous real-reactive power compensator. This paper illustrates the model for determining total active and reactive power requirements before providing the autonomous power-sharing in decentralized grid using MATLAB-Simulink.