DC Link Voltage Balancing of the Active Front-End for the Extreme Fast Charging Stations


One of the most important challenges of the extreme fast charging (XFC) stations is to balance the DC link voltages of the active front-end (AFE). The multilevel cascaded H-bridge (CHB) converter is a great topology for the AFE applications due to the high power density, low total harmonic distortion (THD), and a low number of active and passive components. In this paper, a technique is proposed for balancing DC-link capacitor voltages of a three-phase CHB converter, when a phase shift-PWM modulation technique is used on all cells of the converter. To reach this goal, the redundant states of the CHB converters are used for generating different AC voltage levels by sorting the voltages of the converters. The proposed voltage balancing technique uses the principles that are employed for the DC link voltage balancing of the low-frequency modulation techniques to balance the DC link voltages of the CHB converter. As shown in this paper, the DC link voltages of the CHB converter can accurately be balanced very fast without using PI controllers, which are used in the conventional DC link voltage balancing techniques. A controller also is proposed which will be used to control the dq currents of the CHB converter. To verify the advantages of the proposed technique, the simulation results of the proposed technique will be carried out in a three-phase 7-cell CHB AFE.

Meeting Name

2020 IEEE Energy Conversion Congress and Exposition, ECCE )2020: Oct. 11-15, Virtual)


Electrical and Computer Engineering


U.S. Department of Energy, Grant DE-EE0008449

Keywords and Phrases

Cascaded H-Bridge; DC Link Voltage Balancing; Fast Charging Station; Grid-Tied Converters

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2020 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

30 Oct 2020