Modeling and control of grid connected voltage source converter for power sharing

Use of distributed resources is growing in the world and India is no exception. The acceptance of such resources has increased mainly due to their modularity, increased reliability, good power quality and environment friendly operation. These renewable energy sources are currently being interfaced to the existing systems using voltage source converters (VSC´s). The control of such distributed resources is significantly different than the conventional power systems with the synchronous generators due to the VSC´s having no inertia. This paper deals with the modeling, design and control aspects of a distributed energy source feeding a common load in the presence of utility grid. Two control algorithms are developed for real and reactive power sharing of the load between the distributed source and the grid. The developed control schemes are tested for linear (R-L) load under equal and unequal power sharing. With suitable modifications, the control algorithms can be utilized for connecting several distributed resources in parallel.