Title: A low-frequency fluctuation suppressing method for a seven-level hybrid T-type nested neutral point clamped converter

Authors: Xinmin Jia; Zhe Huang

Addresses: Inner Mongolia Power Co., Ltd., No. 9, Qiandamen Road, Saihan District, Hohhot, Inner Mongolia, China ' Inner Mongolia Power Co., Ltd., No. 9, Qiandamen Road, Saihan District, Hohhot, Inner Mongolia, China

Abstract: This paper proposed a low-frequency fluctuation suppressing method for a seven-level hybrid T-type nested neutral point clamped (7L-HTNNPC) converter that can be applied in medium-voltage and high-power powertrain systems. The 7L-HTNNPC converter is a combination of a 3L-ANPC unit and a four-level T-type neutral point clamped (4L-TNNPC) unit. The 3L-ANPC unit is modulated to switch at a low fundamental frequency while the remained 4L-TNNPC unit is operated at a high switching frequency. Compared to the existing modulation method, the proposed method has the advantage of resuppressing flying capacitor voltage fluctuations and reducing current harmonics with a low flying capacitance. Simulation results have been presented to verify the proposed low-frequency fluctuation suppressing method for the 7L-HTNNPC converter.

Keywords: low-frequency fluctuation; seven-level; 3L-ANPC; 4L-TNNPC.

DOI: 10.1504/IJPT.2022.124742

International Journal of Powertrains, 2022 Vol.11 No.2/3, pp.143 - 159

Received: 09 Aug 2021
Accepted: 03 Dec 2021
Published online: 08 Aug 2022 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article