Feedforward Compensation Control for Virtual Synchronous Generator to Improve Power Decoupling Capability

摘要

Virtual synchronous generator (VSG) control enables grid-connected converter to behave in a similar way with the synchronous generator (SG), which is helpful to enhance the stability of the power system. However, the power coupling between the active power loop (APL) and reactive power loop (RPL) has negative effect on the dynamic performance of the power system and even lead to instability. A thorough inquiry into the power coupling is made in this paper. Analysis indicates that coupling stems from the output voltage. Nevertheless, this could not be thoroughly solved by virtual inductor. And, the implementation of virtual inductor may cause the stability concern. Hence, a feedforward compensation method is proposed to tackle it. Specifically, the reference value of voltage control loop is adjusted according to the active power output of the voltage-source converter (VSC). With this method, power coupling can be significantly reduced. Furthermore, the proposed method eases the concerns regarding power quality and stability. Finally, simulation results are presented to verify the effectiveness of the proposed method.