Virtual Synchronous Generator Control Strategies For Low-Inertia Power Systems: A Comprehinary Review
Abstract
The increasing penetration of renewable energy sources has reduced rotational inertia in modern power systems, causing frequency instability and weakened grid strength. Virtual Synchronous Generators (VSGs) have emerged as a leading grid-forming control strategy that enables power converters to emulate synchronous machine behavior. This paper addresses three core questions: (a) the problem – reduced inertia threatens grid stability through higher rates of change of frequency (RoCoF) and deeper frequency nadirs; (b) the solution – VSG control strategies that embed the swing equation into converter loops to provide synthetic inertia and damping; (c) the results – systematic comparison shows voltage-controlled VSG and synchronverter approaches provide the strongest grid-forming capability, while impedance-based analysis reveals stability margins depend critically on the impedance ratio between VSG and grid. This paper systematically classifies existing VSG approaches based on control philosophy, modeling frameworks, and parameter tuning strategies, identifying key research gaps. The study examines dq-frame modeling, impedance-based stability analysis, and small-signal eigenvalue techniques. Major challenges include inertia–damping trade-offs, parameter tuning inconsistencies, multi-converter interactions, and weak-grid instability. The conclusion is that future research must focus on adaptive control frameworks, hardware validation, and standardized benchmarking systems for widespread practical deployment.