A Novel Distributed Secondary Control of Heterogeneous Virtual Synchronous Generators via Event-Triggered Communication

At present, the distributed cooperative control method has been widely adopted in the secondary control of the conventional droop-based microgrid (MG). However, its application in the secondary control of Virtual Synchronous Generator (VSG) is relatively lagging. Based on the conventional virtual governor, this paper designs the frequency distributed secondary control strategy of VSG based on the theory of nonlinear heterogeneous multi-agents and presents the distributed active power sharing control strategy. The frequency will converge to the frequency reference value through the consensus protocol, instead of relying on the virtual frequency modulation coefficient. To reduce the communication burden, a control strategy based on event-triggered is adopted in the distributed secondary control. The distributed control is used in frequency strategy, compared with the VSG secondary control proposed previously, the distributed generations (DGs) can collaboratively work. Compared with the existing conventional droop-based distributed secondary control, the proposed scheme retains the characteristics of VSG and can provide virtual inertia to MG. An islanded microgrid test system was established to verify the proposed control strategy. The results show that the proposed control strategy can restore the frequency to the reference value and accurately share the active power, while greatly reducing the communication burden.