Virtual Synchronous Generator Control Strategies for Frequency Stability in Grid-Forming Inverter-Based Power Systems

As more of our power systems are overtaken by renewable energy sources (RES), the problem of grid stability has increased. Renewable energy sources that are inverting, do not have the natural inertia afforded by traditional power plants to aid in the smoothing of the fluctuation of contagions, and this could make the system susceptible to failures. One of the possible ways is through the use of grid-forming inverters (GFMIs) with virtual synchronous generator (VSG) control, which mimics the behavior of conventional machines. The present research uses extensive MATLAB simulations in both normal and fault mode to compare three different VSG control methods namely active-power, q-axis voltage and phase-locked loop (PLL). The results show that active-power strategy is the one that provides the most continuous reliable performance, which suppresses disturbances at a higher rate and better retains frequency as opposed to others. In comparison, q-axis voltage method produced continuous oscillations, whereas the PLL method was problematic with larger deviations. Based on these findings, active-power-based VSG regulation is the most reliable way of ensuring frequency stability in grids with high levels of renewable energy sources.