Cascade multilevel STATCOM as a solution to improve the voltage profile of a power grid

In this paper a cascade multilevel Static Synchronous Compensator (STATCOM) is presented and controlled to improve the voltage profile of the power grid. The STATCOM uses a star configured Cascade Multilevel Converter (CMC), and a Phase-Shifted Pulse Width Modulation strategy. A voltage balancing technique for the DC capacitors is designed to guarantee that their voltages do not diverge significantly. The developed system is tested, and the obtained results show that the CMC-STATCOM guarantees the regulation of the voltage at the Point of Common Coupling (PCC) even in the occurrence of voltage sags, and allows the operation with a reduced number of modules, while guaranteeing the capacitors voltage balancing.