PROJECT TITLE :

Power and Voltage Balance Control of a Novel Three-Phase Solid-State Transformer Using Multilevel Cascaded H-Bridge Inverters for Microgrid Applications

ABSTRACT:

This paper presents a new application of power and voltage balance control schemes for the cascaded H-bridge multilevel inverter (CHMI)-based mostly solid-state transformer (SST) topology. To scale back load on the controller and simplify modulation algorithm, a master–slave management (MSC) strategy is designed for the twin active bridge (DAB) stage. The master controller executes all management and modulation calculations, and also the slave controllers manage solely device switching and protection. Due to the inherent power and dc-link voltage unbalance in cascaded H-bridge-primarily based SST, this paper presents a compensation strategy primarily based on three-phase dq decoupled current controller. An optimum zero-sequence element is injected in the modulation scheme therefore that the 3-phase grid currents are balanced. Furthermore, to tightly regulate the output voltage of all the DAB modules to target value, a dynamic reference voltage technique is also implemented. With this proposed control technique, the 3-phase grid currents and dc-link voltage in every module can be simultaneously balanced. Finally, simulation and experimental results are presented to validate the performance of the controller and its application to microgrid SST.