Fixed-time Phase and Frequency Synchronization Strategy for VSG-based Inverters in Microgrids

The uncertainty during phase and frequency synchronization, caused by high penetration of large-scale distributed generators (DGs) in microgrids (MGs), promotes certain inertia requirement, which can be partly supported by virtual synchronous generator (VSG) based inverters. This paper establishes a second-order kuramoto-oscillator model for islanded MGs containing VSG-based inverters, under which a fixed-time sliding-mode synchronization strategy is proposed to achieve phase and frequency synchronization simultaneously. By adding a power term in sliding-mode surface to estimate disturbance within a fixed time, sufficient parameter conditions with simple forms are derived to decouple dependency of synchronization time on initial states. Compared with existing results, system transient and steady-state stability as load variation and grid connection can be significantly improved, which are validated through MATLAB/SimPowerSystems.