Passivity-based Control of Cascade D-STATCOM

To regulate the reactive power into power grid,the distribution static synchronous compensator(D-STATCOM) has been considered as one of the most valid methods due to its salient features.Cascade D-STATCOM,constructed by cascading several identical H-bridge(single-phase full bridge) inverters,is a strong-coupled and multiple variable nonlinear system,which makes it is very difficult to simultaneously realize the reactive current,dc voltage stability and balancing control.This paper built up the passivity-based control model of single H-bridge module,and then realized the reactive current and dc voltage stability control of cascade D-STATCOM based on this.Dc voltage balancing control was realized based on the power exchange among H-bridge modules.The validity and feasibility of this control strategy is verified by simulation results,and has been used on practical engineering of ±5Mvar,10kV D-STATCOM.Based on this,a basic insurance and good platform is provided for the study and development of cascade D-STATCOM.