A Fault Detection and Protection Scheme for Three-Level DC–DC Converters Based on Monitoring Flying Capacitor Voltage
Venue
IEEE Transactions on Power Electronics, vol. 27 (2012), pp. 685-697
Publication Year
2012
Authors
Honggang Sheng, Fred Wang, C.W. Tipton
BibTeX
Abstract
Fault detection and protection is an important design aspect for any power
converter, especially in high-power high-voltage applications, where cost of
failure can be high. The three-level dc-dc converter and its varied derivatives are
attractive topologies in high-voltage high-power converter applications. The
protection method can not only prevent the system failure against unbalanced
voltage stresses on the switches, but also provide a remedy for the system as
faults occur and save the remaining components. The three-level converter is
subject to voltage unbalance in certain abnormal conditions, which can result in
switch overvoltage and system failure. The reasons for the unbalanced voltage
stresses are fully investigated and categorized. The solutions to each abnormal
condition are introduced. In addition to the voltage unbalance, the three-level
converters can be protected against multiple faults by the proposed protection
method through monitoring the flying capacitor voltage. Phenomena associated with
each fault are thoroughly analyzed and summarized. The protection circuit is simple
and can be easily implemented, while it can effectively protect the three-level
converters and its derivatives, which has been verified by the experiment with a
three-level parallel resonant converter.
