Transformer Based 25-Level T-Type MLI for Renewable Energy Integration

The primary challenge with cascaded H-bridge multilevel inverters (MLI) is the need of a large number of switching components and distinct dc-sources for integration of renewable energy to medium voltage grid. As a result, in these types of systems, component minimization is crucial. With the advent of transformer cascaded multilevel inverters (TCMIs), multiple dc sources in cascaded H-Bridge (CHBs) are no longer required for operation. According to the findings of this research, a novel transformer cascaded MLI with 25 levels and 12 switches can be implemented using a single dc source. The proposed MLI is comprised of two different rated isolated transformers. The proposed MLI topology offers the structural advantage of fewer semiconductor components, provides self-galvanic isolation, and generates uniform voltage levels for all turn's ratio. Furthermore, the MLI employs a switching mechanism known as nearest level control, which reduces device power loss and, hence, enhances the systems overall efficiency. To assess the performance of the proposed TCMLI, a laboratory prototype was built and simulations in the MATLAB/Simulink environment were run. In addition, a study of the systems power loss analysis has been presented. A comparison of the proposed topology to other recent topologies of a similar nature is also provided.