Operating principles of shunt STATCOM based on 3-level diode-clamped converters

This paper offers a novel topology for the implementation of a shunt STATCOM based on a grouping of four three-level, diode-clamped power converters, switching at line frequency and coupled to the AC system through wye/wye and wye/delta phase-shifting transformers. Advantages include direct voltage control through the gating pattern and reduced size of DC capacitor. The dominant harmonic on the AC side is the 11th and on the DC side the 12th. The proposed STATCOM can meet typical harmonic distortion requirements.