Reliability assessment of Modular Multilevel Converters by industrial and military prediction models

In last years, Modular Multilevel Converters have been applied in various contexts, especially as distributed renewable interfaces toward the electric grid. In these applications a critical task is represented by converters reliability assessment since preliminary design steps. In detail, the attention is focused on the Cascaded H-Bridge topology and its multilevel configurations. A military (Military Handbook 217F) and an industrial (FIDES 2009) prediction models are employed to CHB quantitative reliability evaluation. In this paper both Part Count and Part Stress methodologies are applied to operative case studies. The relative procedures are carried out by a commercial software tool (RAM Commander®) and by the Converter Design software developed at the ENEA Research Centre of Portici. The innovative aspect of the proposed software consists in a reliability-oriented design process dedicated to Modular Multilevel Converters.