Parallel Operation of Virtual Synchronous Generators in a Microgrid

Virtual synchronous generators can be operated in parallel for load sharing in a microgrid wherever it is required. Besides the load sharing, virtual synchronous generators can inject a controllable amount of virtual inertia into the microgrid whenever it is needed. However, due to the different rates of frequency change resulting from the different virtual moments of inertia, the dynamic performance of multiparallel virtual synchronous generators may be different. The ones with large inertia need a long time to respond to the load changes. Whereas, the ones with small inertia respond faster. Accordingly, the system may be affected in terms of frequency and power. Thus, this article focuses on how to match the virtual inertia as well as the damping coefficient to improve the parallel operation during steady state and the system transients for better dynamic performance. To that end, the inertia and damping matching mechanisms for multi-paralleled virtual synchronous generators are introduced. The results are proven by the simulations and experiments.