Fixed-reference-frame-control: A novel robust control concept for grid side inverters in HVDC connected weak offshore grids

摘要

Offshore wind energy plants built at a long distance from public ac-grid are connected by HVDC-transmission. Hence an offshore ac-island-grid results, in which the HVDC station generates the grid while the inverters of the wind power plants synchronize themselves on that gird. As the power of the HVDC-station is not significant higher than that of the sum of all wind power plants, the grid is relative weak. This could lead to stability problems of wind power plants grid side converters.