Performance Analysis of Homogeneous and Heterogeneous Microgrid based on Droop and VSG-Based Control

The increased penetration of inverter-based distributed generation has led to the coexistence of diverse control strategies, such as droop control and virtual synchronous generator (VSG) control, for proportional power sharing. Although most existing studies are confined to homogeneous systems with identical controlled schemes, this paper addresses the emerging need to analyze heterogeneous microgrids incorporating droop and VSG-controlled inverters. A key challenge in such systems is the deviation in frequency and voltage under dynamic conditions. To address this, a decentralized washout filter-based control strategy is proposed, eliminating the extensive communication requirement. Further, the paper presents a small-signal stability analysis of the heterogeneous microgrid and investigates the influence of washout filter parameters on system behavior. The effectiveness of the proposed method is demonstrated through simulations and experimental results carried out on a CIGRE low-voltage distribution network with various combinations of droop and VSG-based inverters.