Zero-Sequence Voltage Injection Method for DC Capacitor Voltage Balancing of Wye-Connected CHB Converter under Unbalanced Grid and Load Conditions

Leg capacitor energy balancing control is one of the crucial issues for stable operation a cascaded H-bridge (CHB) converter. Because this topology inherently consists numerous submodule cells with DC capacitors, cell voltages and leg instantaneously fluctuate depending on sequence CHB In general, wye-connected CHB-converter-based static synchronous compensator (STATCOM) utilizes zero-sequence voltage component balancing. paper, to improve dynamics control, feedforward calculation method injection proposed. The term can be calculated by using information from measured currents, ensures successful regulation balance even under unbalanced grid load conditions. Moreover, verification proposed supported mathematical vector theorems. A 50MVA full-scale CHB–STATCOM system simulation was performed verify considering as well