Advanced control functions for smart grid inverter under asymmetrical conditions

Since photovoltaic systems, wind energy, and other renewable energy resources are concerned as sustainable and environmental friendly for the future grid, conventional energy supply systems are facing a huge change regarding their integration. To assure and provide a flexible and a system compatible integration of those decentralized energy resources, power electronic inverters as grid interfaces between energy conversion systems (ECS) and the main grid getting more important. Hence, the inverter has to join the grid operation functions, e.g. frequency and voltage stabilization, similar to the conventional power plants. By implementation of a new control approach based on symmetrical components, the control speed at asymmetrical load and grid conditions is improved. The control approach is verified in a FPGA based smart grid inverter platform, confirming the potential at a hardware system. When using fast control functions for asymmetrical grid conditions it is possible to guarantee stability of future smart grids at rising penetration of distributed energy resources to the main grid.