A Novel Oscillation Damping Method of Virtual Synchronous Generator Control Without PLL Using Pole Placement

Recent years, in order to avoid probable inertia decrease of power system due to increasing inverter-interfaced distributed generators, virtual synchronous generator (VSG) control, an inverter control scheme providing virtual inertia, has been proposed. However, the resonant mode of basic VSG control results in transient oscillation damping. In this study, a state-space model of a synchronous generator connected to infinite bus is established to study the mechanism of this oscillation and to understand the damping effect of previous VSG control methods. Based on the state-space model, a novel oscillation damping method of VSG using pole placement is proposed. With a very simple state feedback control, the proposed method provides proper damping without any frequency measurement whereas keeps the inertial feature of VSG. Simulation results obtained with PSCAD/EMTDC and experimental results obtained in a laboratorial microgrid testbed indicate that the proposed method outperforms previous VSG control methods with excellent transient performance.