Improved Damping Ratio Control of Virtual Synchronous Generators with Multiple Parameter Coordination

A strategy of co-regulating three parameters P/ω droop modulus, virtual inertia and damping ratio for the virtual synchronous generator (VSG) is presented in this paper. This approach is able to solve the uncoordinated performance between the virtual inertia and the damping modulus using the conventional adaptive control in which case the system may experience serious frequency fluctuations. Through the mathematical modeling of the VSG system, the segmental analysis of the VSG transient process is carried out, and the parameter adjustment law of each stage is obtained. The VSG instantaneous angular velocity change and the rate of angular velocity instantaneous change rate are associated with the inertia to realize the adaptations of the inertia and the P/ω droop modulus is carried out in real time according to the VSG angular velocity change. A functional relationship is established between P/ω droop modulus, virtual inertia and damping ratio, so that the P/ω droop modulus, virtual inertia and damping ratio are coordinated to keep the system in the best damping ratio state all the time. Finally, the superiority of the applied strategy is proved by comparison.