Reduced-Switch Symmetric and Asymmetric Diode Half-Bridge Multilevel Inverters for Renewable Energy Applications: Design, Analysis, and Performance Evaluation

Abstract

The purpose of this research paper is to perform a thorough study of Symmetric Diode Half-Bridge (SDHB) and Asymmetric Diode Half-Bridge (ADHB) multilevel inverter structures for renewable energy and grid-connected systems. In the case of SDHB multilevel inverter structure, equal valued DC voltage sources are used to produce different voltage levels by employing fewer power switches and diodes to have a more reliable and simplified converter structure. On the other hand, ADHB multilevel inverter structure uses unequal DC source values based on binary or trinary voltage ratios to produce significantly enhanced voltage level synthesis using the same number of semiconductor switches. Therefore, it can be observed that the ADHB structure produces better voltage resolution, lesser harmonics, enhanced voltage utilization, and high power density. Their operation principle, switching sequence, voltage generation method, and requirement of components are studied along with their comparison with existing multilevel inverter structures. Their voltage synthesis, modularity, and scalability make these converters more appropriate for renewable energy conversion, energy storage, electric vehicle drives, and grid interface application purposes. Performance analysis shows their improved output voltage quality, lesser semiconductor usage, voltage stress reduction in switches, and conversion efficiency.