Evaluation of Active Capacitor Banks for Floating H-bridge Power Modules

The DC-side floating capacitors in the floating power modules of power converters are subject to high voltage fluctuation, due to the presence of reactive harmonic components. Utilizing passive capacitors, as done in traditional methods, helps reduce the DC-bus voltage ripple but makes the system bulky. An active capacitor can be integrated with the floating H-bridge power modules to remove the effect of the ripple powers on the DC bus. The auxiliary circuit, which is much smaller in size compared to an equivalent passive capacitor, helps increase the power density of the system. This work focuses on the analysis of power components, and the extension of the active capacitor to the Perturbation Injection Unit (PIU), in which the DC side is highly distorted by multiple harmonic components. A control scheme is proposed to compensate for these multiple harmonics and balance the DC-link voltage in the active capacitor. Also, an equivalent DC-bus impedance model is introduced, which is more accurate than that in existing works. Simulation studies and evaluation of the design have verified the effectiveness of the active capacitor solution.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Electrical Engineering

Department dc:contributor.department

Electrical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2020

Author dc:creator

• Nguyen, Tam Khanh Tu

• Active capacitor
• power decoupling
• DC-bus voltage ripple reduction
• floating H-bridge power modules
• single-phase converters
• impedance modeling
• Power Injection Unit
• power density.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:23937

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/104466