A Frequency Deadband-Based Virtual Inertia Control for Grid-Connected Power Converters

Unlike synchronous generators, renewable generators, e.g. photovoltaic (PV) arrays and wind turbines, cannot provide rotating inertia when connected to the grid through power converters. As a result, excessive grid frequency deviations are likely to occur in the event of generator tripping and/or load shedding. An effective approach to increase inertia is achieved by proportionally associating the dc-link voltage of grid-connected power converters with the grid frequency, allowing power converters to generate a fixed amount of virtual inertia for frequency support. To further develop this idea, this paper proposes a frequency deadband-based virtual inertia controller for power converters to perform inertia responses during frequency events. The proposed controller enables the increase of inertia in a shorter time duration, leading to an improved frequency nadir and a reduction of the energy required for inertia emulation. Finally, simulated and experimental results are presented to verify its effectiveness.