Reliability Analysis of IGBT Modules of Multilevel Inverters Operating in Hostile Mining Environments

Throughout many Industries, pulse width modulation voltage source inverters (PWM-VSI) are commonly utilized within adjustable speed drives (ASD) to control induction motors. For many application within various heavy industries, the cables connecting the output of some ASDs to their motor loads can be extremely long. These long cable applications can cause several operational challenges. As an innovative solution, an alternative system configuration has been previously proposed, in which the rectifier is kept in its typical location, and the inverter bridge and DC bus capacitors are installed near the driven motor. The long cables running from the ASD to the motor are used as a DC transmission line, mitigating the high-frequency problems resulting from the inverter-cable-motor interaction. However, new concerns regarding the reliability of the power devices arise once the inverter is installed in harsh ambient conditions. In this context, this work proposes a reliability analysis of such drive configuration, applying the physics of failure (PoF) approach combined with the design for reliability methodology to carry out the design adjustments to achieve the reliability and minimizing implementation costs required for the application, focusing on the inverter IGBT modules. The results show that a three-level active neutral point clamped inverter (3L-ANPC) topology, applying two pulse width modulation (PWM) strategies and 400 Amp. - 6.5 kV IGBTs, would be the most appropriate from this study's reliability and feasibility analyses.