Enhanced Virtual Synchronous Generator Control for Parallel Inverters in Microgrids

TLDR

Virtual synchronous generator control offers communication‑less inertia support in microgrids, yet it suffers from active‑power oscillations, transient sharing issues, and reactive‑power sharing errors inherited from conventional droop control. The paper proposes an enhanced VSG control that dampens oscillations and ensures proper transient active‑power sharing by tuning virtual stator reactance via state‑space analysis. The enhanced control achieves communication‑less accurate reactive‑power sharing using inverse voltage‑droop (V‑Q droop) and common AC bus voltage estimation. Simulations and experiments confirm that the enhanced VSG control improves performance.

Abstract

Virtual synchronous generator (VSG) control is a promising communication-less control method in a microgrid for its inertia support feature. However, active power oscillation and improper transient active power sharing are observed when basic VSG control is applied. Moreover, the problem of reactive power sharing error, inherited from conventional droop control, should also be addressed to obtain desirable stable state performance. In this paper, an enhanced VSG control is proposed, with which oscillation damping and proper transient active power sharing are achieved by adjusting the virtual stator reactance based on state-space analyses. Furthermore, communication-less accurate reactive power sharing is achieved based on inversed voltage droop control feature (V-Q droop control) and common ac bus voltage estimation. Simulation and experimental results verify the improvement introduced by the proposed enhanced VSG control strategy.