Modeling and Stability Analysis of Droop Controlled Islanded DC Microgrids

The dc microgrid’s stability depends on the control strategy employed for each mode of operation (MG). It is the main strategy for preserving bus voltage stability during island operation when there is no connection between sources. This study establishes that the use of droop has an impact on the voltage stability of dc power systems with nonlinear and active loads, such as constant-power loads. An ideal voltage source coupled to an equivalent resistance and inductance can represent all parallel sources and transmission lines. Due to the reduced number of differential equations in this approximate model, a nonlinear stability analysis may be carried out. Additionally, it provides analytical stability conditions as a function of the model parameters, which results in a design principle for reliable (MGs) based on safe operating regions (SOR).