Date of Completion


Embargo Period



Power Electronics, Multilevel Inverter, Fault Diagnosis, Reconfiguration, Power Quality

Major Advisor

Ali M. Bazzi

Associate Advisor

Krishna Pattipati

Associate Advisor

Sung-Yeul Park

Field of Study

Electrical Engineering


Doctor of Philosophy

Open Access

Campus Access


This dissertation proposes new models, reconfiguration, and optimization of multilevel inverters in healthy and faulty conditions. The aim of this dissertation is to develop robust and practical multilevel inverter systems to improve the power quality of post-fault multilevel inverters. To improve the power quality, five essential parts are discussed in this dissertation.

In the first part, an accurate mathematical model of neutral-point clamped (NPC) multilevel inverters is derived and utilized to analyze the impact of different types of component failures and existing reconfiguration methods on power quality.

In the second part, a logic-based generalized fault diagnosis method is developed and implemented in multilevel inverters to detect major failures of multiple semiconductor devices. Existing reconfiguration methods are integrated with the proposed fault diagnosis method to recover the post-fault multilevel inverter from faulty conditions.

In the third part, a logic-based fault prognosis method is proposed to predict the failure of semiconductor devices in multilevel inverters.

In the fourth part, a practical reconfiguration method is proposed to overcome several shortages of existing reconfiguration methods.

In the fifth part, factors that impact the power quality of multilevel inverters are analyzed and optimization methods are utilized to analyze the impact factors to reduce the degradation of power quality in reconfigured conditions.