The imbalance problem of DC capacitor voltage existing in cascade STATCOM is studied by using ladderwave modulation method in this paper. The basic principles of ladder wave modulation method and current indirect con-trol are introduced,and the variation relationship between conduction angle and capacitor voltage is analyzed. On thisbasis,the ladder wave modulation method is modified,and a novel capacitor voltage balance strategy based on the mod-ified ladder wave modulation method is proposed,which makes the width of rising region of voltage c...
