In this paper a new method four-leg topology is suggested for shunt compensation, the H-bridge multilevel converters based on the half-bridge converters, to achieve higher performance as a STATCOM in a distorted and unbalanced medium-voltage large-current system. Further, an extended Fuzzy based STATCOM is proposed in order to manage more accurate compensation for high-power applications. Both proposals can be controlled for various purposes such as reactive power and unbalance compensation,

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... tage regulation, and harmonic cancellation. One interesting application for the Fuzzy logic based STATCOM could be the improvement in power quality and performance of the electrified railway traction power supply system. Both the H-bridge based STATCOM along with their proposed control strategies were simulated.