Transient Power Overshoot Suppression Strategy of Generalized Droop
Control with Constrained RoCoF
Abstract
With the renewable energy continuously access to the microgrid,
the microgrid itself does not have the disadvantages of the inertia of
the synchronous generator in the traditional grid is increasingly
apparent, for which the generalized droop control (GDC) strategy is
proposed. In the normal operation of the system, GDC has the advantages
of large inertia and small active power overshoot, but when subjected to
external frequency perturbations, the grid-supporting inverter with
large virtual inertia is prone to large transient active power overshoot
and oscillation. To address this problem, the article
establishes small-signal models under different perturbations based on
the GDC compared with the virtual synchronous generator (VSG) and
further proposes two adaptive inertia control strategies: GDC adaptive
inertia (GDCAI) and adaptive inertia for operation mode switching
(AIOMS). By adjusting the virtual inertia appropriately, the rate of
change of frequency (RoCoF) is maintained in the set range while
improving the transient performance of the system, the methods of
reduce-order of the system model and control parameter design is given,
to reduce the frequency fluctuation while greatly reducing the active
power overshoot and improving the response speed of the system.
The effectiveness of the two control strategies is verified by
MATLAB/Simulink simulation and StarSim hardware-in-the-loop (HIL)
experiment.
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