DC Leakage Current Reduction for Single-Phase Full-Bridge Converter

The switching-frequency dc leakage current issue exists in the single-phase full-bridge topology with the unipolar modulation switching scheme. It is important to reduce the leakage current, which has a negative impact on the solar panels. With the emerging market on solar inverter, there are lots of patents filed by different companies on solving this issue. The examples are seen in H5 inverter, HERIC inverter, and etc. In this invention, a simple passive solution is proposed to effectively reduce the dc leakage current. A common-mode choke and a pair of split differential-mode capacitors forms as a LC low-pass filter to attenuate the dc common-mode switching noise. The design procedure of the passive filter is easy and straightforward. The proposed method just utilizes the existing ac L-C-L type harmonic filter and EMI filter; thus it doesn't introduce the extra cost and additional power loss.
Patent Information:
For Information, Contact:
Li Chen
Licensing Associate
Virginia Tech Intellectual Properties, Inc.
(540) 443-9217
Dong Dong
Fang Luo
Dushan Boroyevich
Paolo Mattavelli