Control of grid-connected power converters based on a virtual admittance control loop

The connection of electronic power converters to the electrical network is increasing mainly due to massive integration of renewable energy systems. However, the electrical dynamic performance of these converters does not match the behavior of the network, which is mainly formed by generation facilities based on big synchronous generation systems. Depending on the desired electrical operation mode different control structures can be implemented in the converters in order to get adapted with the grid conditions. However, changing between different control structures and operation is not an optimal solution, as the resulting system results complex and is not highly robust. As an alternative, this paper presents a new control technique for grid connected power converters based on the concept of virtual admittance. The proposed control permits to emulate the electrical performance of generation facilities based on classical synchronous generators with a power converter, with no need of implementing different control structures, giving rise to a system that provides a friendly and robust operation with the network.