Improvement of current and voltage problems occurring on solid state transformer components

With the widespread adoption of distributed systems and renewable energy, numerous challenges such as power quality, reverse and back power flow issues have begun to emerge. This thesis aims to investigate the current and voltage problems occurring in the stages and components of Cascaded H-Bridge-Based Solid State Transformers (SST). Among the stages of SSTs are the AC/DC converter stage, the dual active bridge stage along with the high-frequency transformer stage located at the center of the dual active bridge, and among its components are H-bridge modules, power electronic converters, high-frequency transformers, and control systems. The problems that arise in these components can be listed as current issues such as unbalanced currents, harmonics, and overloading, as well as voltage fluctuations, voltage drops, overvoltage, and voltage imbalance. The modeling and simulation of the circuits in this study were performed using the PSCAD/EMTDC software. To improve current and voltage issues, analyses and comparisons were conducted using different switching techniques and controllers, and recommendations were presented.