Investigation of the Virtual Synchronous Machine in the Island Mode

In this paper the investigation results of the Virtual Synchronous Machine (VISMA) in the island mode are presented. The increasing integration of the distributed generation units leads to continual growing of the amount of the inverter interface in the electrical grid. Therefore, the characteristics of inverters will more and more significantly influence the grid operation. The VISMA is a novel control method for the inverter to make it possible that an inverter-interfaced decentralized generation unit can be operated as a real electromechanical synchronous machine, which up to now as the main generation unit in the electrical grid has many advantages in consideration of the grid stability. These advantages can be implemented in the VISMA and are proved experimentally in the grid-connected operation mode. The island-mode is another important operation mode that will be necessary for a stand-alone grid without connecting of the main grid or when the main grid fails due to a disturbance. Therefore this operation mode of the VISMA is focused in this paper.