Virtual Reactance Implementation Method for Droop-Controlled Three-Phase Microgrid Inverters Using SOGI Scheme

Abstract

Because the line impedance of low-voltage microgrids is mainly resistive and the transfer impedance of microgrid inverters is usually mismatched, a virtual reactance is usually added to the control loop of each microgrid inverter. It is found that the existing two virtual reactance implementation methods introduce harmonic components into the voltage control units of microgrid inverters in the condition of nonlinear loads after the theory and simulation analyses. To solve the problem, a second-order general-integrator (SOGI) virtual impedance implementation method of droop-controlled three-phase microgrid inverters is proposed. Simulation results are provided to show the feasibility of the proposed method.