Doctoral Dissertations

Keywords and Phrases

Capacitor Voltage Regulation; Cascaded H-bridge; Flying Capacitor; Multilevel Converters; Multi-level Inverters; Power Electronics


Multilevel power electronic converters are the current industry solutions for applications that demand medium voltage, reasonable efficiency, and high power quality. The proper operation of these types of power converters requires special control, modulation methods, and capacitor voltage regulation techniques. Both developing capacitor voltage regulation methods and addressing their associated issues with such fall within the primary focus of this dissertation. In this dissertation an investigation was conducted on the capacitor voltage regulation constraints in cascaded H-bridge multilevel converters with a staircase output voltage waveform. In the proposed method, the harmonic elimination technique is used to determine the switching angles. A constraint was then derived to identify modulation those indices that lead to voltage regulation of the capacitor. This constraint can be used in optimization problems for harmonic minimization to guarantee capacitor voltage regulation in these types of converters. Furthermore, a capacitor voltage regulation method was developed using redundant state selection for a flying capacitor active rectifier. This method reduces the number of switching instances by using both online and offline state selection procedure. Additionally, a start-up procedure is proposed that pre-charges the all of capacitors in the rectifier to both avoid overstressing the switches and obtain a smoother start-up. Finally, a flexible capacitor voltage regulation method is proposed that provides the ability to control the voltage of the capacitors in both cascaded H-bridge and hybrid multilevel converters. In this method, the capacitor voltage in each individual H-bridge cell is independently regulated by controlling the active power of each cell.


Ferdowsi, Mehdi
Corzine, Keith, 1968-

Committee Member(s)

Kimball, Jonathan W
Landers, Robert G
Crow, Mariesa


Electrical and Computer Engineering

Degree Name

Ph. D. in Electrical Engineering


Missouri University of Science and Technology

Publication Date

Fall 2012


xii, 111 pages

Note about bibliography

Includes bibliographical references.


© 2012 Hossein Sepahvand, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Subject Headings

Electric current converters
Electric current rectifiers
Electric inverters

Thesis Number

T 10103

Electronic OCLC #