A new publication from our ECS4DRES consortium has just appeared in IEEE Transactions on Industrial Electronics:
“Mitigation of Active Power Oscillation in Multi-VSG Grids: An Impedance-Based Perspective”
As grid-forming converters move from single devices to systems of interacting controllers, stability questions are no longer device-level problems - they become networked dynamical problems.
The paper shows how the classical RLC-circuit analogy provides an intuitive physical interpretation of VSG control and helps explain why multiple VSG units may oscillate even when each converter is individually stable. By systematically analysing inertia, damping, feeder impedance, and grid strength, it clarifies that active-power oscillations arise from different mechanisms in stand-alone, strong-grid, and weak-grid conditions.
Based on this understanding, the authors develop:
- a graph-theory-based virtual impedance tuning method
- adaptive inertia and adaptive damping control strategies
- coordinated reactive-power sharing to mitigate active-power oscillations
One particularly important takeaway is the practical trade-off between oscillation suppression and achievable closed-loop bandwidth — a point highly relevant for real grid-forming deployments.
This work nicely illustrates a broader shift in power systems: stability in converter-dominated grids increasingly emerges from the interaction of distributed control algorithms, not from individual hardware characteristics.
Congratulations to the authors: Junjie Xiao, Lu Wang, Xiong Du, Pedro Rodriguez, Zian Qin
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