Stability Analysis Considering Dual Physical Constraints of Parallel-connected Virtual Synchronous Generators forming Microgrids

Although virtual synchronous generator (VSG) is a promising solution to low inertia and damping of the power electronics-based power system, improper parameter design will lead to instability of such a system. In this paper, a VSG parameter design strategy is proposed by considering both AC and DC restraints for a paralleled inverters system, where the active power output of VSG is restricted by the maximum power limit of the converters in AC side, with the energy supply bounded by the energy margin of power source in DC side. Detailed stable operation boundaries are investigated using small-signal mode by considering the dual physical constraints and the stable constraints. Therefore, the proposed parameter tuning method can not only provide enough virtual inertia for stable operation of the system, but also satisfy the power and energy restraints in practice. Detailed simulation results verified the effectiveness of the proposed strategy.