Broad Comparison of Multilevel Inverter Topologies Operating in Hostile Environments: DC Transmission Applicability and Feasibility

Abstract

Especially in the mining industry, Pulse Width Modulation Voltage Source Inverters (PWM-VSI) driving induction motors located far away are often present. In this case, due to the long cable used for the converter-to-motor connection, several unwanted high-frequency phenomena are generated. In this context, a new configuration for motor drive systems was proposed, in which the rectifier is kept in its original position and the inverter bridge is installed close to the motor terminals, being the long cable used as a DC transmission line. Since this environment is always more hostile and can compromise the inverter lifetime, new concerns regarding the system reliability arise, despite the various technical-economic advantages from this new configuration. In this way, this paper presents a comprehensive comparison of commercially widely accepted multilevel inverter topologies, searching for the best technical features for the aforementioned DC transmission applicability/feasibility. Simulations were performed assessing several essential quantities/indexes, with major focus on reliability. Then, a discussion was made seeking those sets that could minimize the implementation costs and improve the system reliability, concerning the IGBTs and the Metalized Film (MFC) and Aluminum Electrolytic (AEC) capacitors of the DC link.