VSC Control and Parameters Design Based on Virtual Synchronous Generator

To cope with the problems that the VSC lacks inertia and synchronous generator controls slowly, the paper combines the advantages of VSC and synchronous generator together to present a control scheme of virtual synchronous generator and a parameters design method. To solve the mutual influence of droop and virtual damping coefficients, a method of combining output frequency and line frequency feedback control is proposed to decouple the two coefficients regulation process while without using the differentiation. Mode switching between constant power and droop control under frequency large disturbance in large scale based on frequency hysteresis control is proposed to maintain system stability. The switching process is realized only through the outer power loop while the inner loop stays the same. At last, a quasi-synchronous-generator parameters design method is established combining the flexible and rapid control characteristics of VSC and the synchronous generator unit's self-droop and self-synchronizing characteristics. The simulation result verified the correctness of theoretical analysis and control scheme.