Feasibility of Capacitor Voltage Regulation and Output Voltage Harmonic Minimization in Cascaded H-Bridge Converters


Multilevel converters have found popularity in electric-drive vehicles. In cascaded H-bridge multilevel converters, it is advantageous to use only one DC voltage source for the main H-bridge cell and supply the rest of the cells with capacitors. However, regulating the capacitors' voltage level becomes a challenging issue. This paper studies the existing constraints on regulating the capacitor voltage levels especially with respect to the elimination of the fifth and seventh harmonics. Detailed as well as simplified analyses are presented and verified. In addition, the constrained nonlinear optimization method is used to find the switching angles that regulate the capacitor voltage, eliminate the fifth harmonic, and minimize the combination of seventh and eleventh harmonics.

Meeting Name

25th Annual IEEE Applied Power Electronics Conference and Exposition (2010: Feb. 21-25, Palm Springs, CA)


Electrical and Computer Engineering

Keywords and Phrases

Capacitor Voltages; Cascaded H-Bridge; Cascaded H-Bridge Converter; Constrained Nonlinear Optimization; DC Voltage Sources; Electric-Drive Vehicles; Fifth Harmonics; H-Bridge Cells; Multilevel Converter; Output Voltages; Simplified Analysis; Switching Angles; Voltage Levels; Automobile Electronic Equipment; Capacitance; Constrained Optimization; Harmonic Analysis; Power Electronics; Voltage Regulators; Capacitors; Voltage Control; Power Harmonic Filters; Optimization Methods; Switching Converters; Reactive Power; Power System Harmonics; Electric Vehicles; Harmonic Distortion; Inverters; Voltage Control; Bridge Circuits; Electric Drives; Optimisation; Power Conversion Harmonics

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version


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© 2010 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Feb 2010