Analisis Stabilitas Tegangan pada Sistem Microgrid DC Islanded Menggunakan Metode Droop Control Berbasis MATLAB/Simulink

Abstract

The increasing penetration of intermittent renewable generation and constant power loads (CPLs) on distribution networks requires an islanded DC microgrid architecture capable of maintaining bus voltage stability without relying on inter-unit communication. This study analyzes the voltage stability of an islanded DC microgrid integrating photovoltaic (PV), wind turbine, and a battery energy storage system (BESS) using primary droop control, simulated in MATLAB/Simulink with the Simscape Electrical library. Three disturbance scenarios were tested: (1) irradiance and wind speed variation, (2) CPL load-step stress testing, and (3) BESS mode transition from charging to discharging following total PV outage. Simulation results show that the steady-state bus voltage remains within 433.74-435.77 V (a deviation of +8.44% to +8.94% relative to the 400 V nominal) across all scenarios, with a maximum undershoot of -2.75% and a maximum overshoot of +1.34% relative to the pre-disturbance steady state, and a transient recovery time of less than 30 ms. Eigenvalue analysis at the nominal operating point confirms that all system modes lie in the left-half-plane, with a dominant mode of λ6 = -85 rad/s yielding a theoretical rise time of 25.87 ms and settling time of 35.29 ms, consistent in order of magnitude with the time-domain simulation results. All bus voltage values remain within the IEEE 1547 and IEC 61727 tolerance bands (±10%). The study concludes that primary droop control effectively maintains DC microgrid voltage stability under the tested source and load disturbances, while still exhibiting a voltage offset as an inherent trade-off of simple droop control.