Obtaining Robust Performance of a Current Fed Voltage Source Inverter for Virtual Inertia Response in a Low Short Circuit Ratio Condition

Low inertia levels are typical in island power systems due to the relatively small rotational generation. Displacing generation units with static inertia-less PV results a significant increase frequency volatility. Virtual provided by inverter-storage can resolve this issue. However, low short circuit ratio (SCR) at point of common coupling together fast phase locked loop (PLL) will compromise response performance system. To address issue, robust PI controller (RPI) for inner current-loop current fed grid-connected inverter is proposed. The PLL disturbance and grid impedance incorporated into single model recast generalized representation system, thereby allowing easy tuning RPI mixed sensitivity H∞ method. compared that (PI) tuned regular loop-shaping show when SCR above 10, both controllers equivalent. lowering compromises system it becomes underdamped < 2. On contrary, capable maintaining nominal throughout same decrease.