Virtual Inertia Emulation Inspired Predictive Control to Improve Frequency Stability in Power Electronics Dominated Grid

摘要

Power electronics-dominated grid (PEDG) has low inertia owing to the fast switching and the reduced penetration of rotating masses, which makes such grids vulnerable to disturbances. This paper proposes a predictive control scheme that emulates virtual inertia to achieve resilient and stable operation of the PEDG in response to load and generation disturbances. The conventional primary control layer for power electronics-based generation commonly utilizes cascaded PI controllers to regulate active/reactive power. This paper eliminates the need for cascaded linear control and employs a model predictive control (MPC) that enables virtual inertia emulation. Leveraging the inherent bandwidth of MPC enables tracking the desired rate of change of frequency (ROCOF) for various disturbances superior than the PI-based controllers. The MPC's penalty function replaces the cascaded linear control while eliminating significant tuning efforts. The investigated virtual inertia topologies for gird-following (GFL) and grid-forming (GFM) inverters are capable of regulating the ROCOF under frequency events. Several case studies are presented to demonstrate the inertia emulation effect considering the interaction between GFL and GFM inverters in PEDG.