An Optimized Virtual Synchronous Generator Control Strategy for Power Decoupling in Grid Connected Inverters

To improve the stability of renewable power generation in micro-grid, a power decoupling control based virtual synchronous generator (PDVSG) is investigated in this paper. A micro-grid is decentralized and has non-synchronized generation units. By adding energy store systems, virtual synchronous generator control-based inverter can reduce the no-inertia impact in micro-grid. However, when the inverter changes between the grid-connected and islanding modes or executes the power command, the conventional VSG control may cause the inrush current or frequency oscillation issue. To address this problem, the excitation controller and prime motor controller are proposed for decoupling active/reactive power and suppressing frequency oscillation. In addition, the proposed VSG strategy does not introduce the steady-state error. The simulated and experimental results of conventional VSG and proposed VSG controllers are presented to validate the effectiveness of the proposed control algorithm.