Method for evaluating degree of parallel SVG (H-bridge cascade) higher harmonic circulating current

The invention provides a method for evaluating the degree of parallel SVG (H-bridge cascade) higher harmonic circulating current, belongs to the technical field of power quality analysis and control, and aims to provide a circulating current access and static equivalent model according to the harmonic circulating current problem generated after parallel connection of SVG with a cascade H-bridge cascade structure and provide a method for evaluating the degree of parallel SVG (H-bridge cascade) higher harmonic circulating current based on indirect detection technology. The method comprises the following steps: constructing a model; analyzing the circulating current rate of two 2-cascade parallel SVG; simplifying calculation; calculating an actual circulating current rate equation; fitting each set of correction factor discrete values by utilizing a least square method in frequency bands; further pushing out a circulating current general formula; and calculating the criterion condition of the actual circulating