Droop Control Based on Improved Virtual Impedance in a Stand-Alone Microgrid

A virtual impedance approach is added to the inverter control loop to improve active and reactive power sharing when the line impedance is less inductive. However, the conventional droop control with virtual impedance cannot properly solve adverse impacts caused by nonlinear loads and noise, such as output distortion. Therefore, this paper proposed virtual impedance with a high-order general-integrator (HOGI) approach to reduce distortion of the output voltage and current as well as to improve power-sharing between parallel distributed generations (DGs). The Matlab/Simulink simulation results verified that the proposed method improved the control system performance.