Analysis and Mitigation of Subsynchronous Resonance in Series-Compensated Grid-Connected System Controlled by a Virtual Synchronous Generator

Grid-Synchronization Stability of Converter-Based Resources—An Overview

“…In addition to stiff-grid scenarios, grid-forming converters can also induce sideband oscillations in series-compensated weak grids [21]. In such cases, the grid impedance has an abrupt change from inductive to capacitive behavior near the fundamental frequency, which tends to interact significantly with the grid-forming converter and lead to the sideband oscillations.…”

“…(c) Active power feedforward [76] or frequency dependent voltage control [77], [78]. (d) Virtual impedance control [21], [76].…”

“…In addition to the shaping of power control loops, the virtual impedance-based control can be designed with the inner loop dynamics, whose principle in active damping is similar to that for gridfollowing converters [79]. This concept has also been applied to dampen the sideband oscillations in a seriescompensated grid, where a current feedforward control that is directly added to the modulation voltage [21].…”

“…the phase-locked loop (PLL) that is commonly found in grid-following converters, can induce sideband oscillations around the grid fundamental frequency in low SCR grids [6], [8], [14], [15]. In contrast, the power-based synchronization algorithms used with grid-forming converters can result in sideband oscillations in stiff grids [16]- [20] and series compensated grids [21].…”

Self‐synchronising virtual induction generator without phase‐locked loop and proportional–integral regulators

“…The design and analysis of the grid‐connected and islanded operation of the VSG are analysed in the literature [20, 21]. This controller analyses the sub‐synchronous resonance in the grid‐connected and islanded operation of VSG.…”