Analysis and Suppression of Harmonic Deteriorations Related to a Few-Submodule and Low-Switching-Frequency MMC-Based UPFC

Bibliographic Details
Title: Analysis and Suppression of Harmonic Deteriorations Related to a Few-Submodule and Low-Switching-Frequency MMC-Based UPFC
Authors: Zhijun Chen, Jun Wang, Ke Zhang, Chao Yu, Yuting Zou, Yunlong Zhao, Mengjie Zhang, Chuyang Wang
Source: IEEE Access, Vol 12, Pp 177692-177710 (2024)
Publisher Information: IEEE, 2024.
Publication Year: 2024
Collection: LCC:Electrical engineering. Electronics. Nuclear engineering
Subject Terms: Unified power flow controller, switching frequency, voltages across the capacitor modules, LLCL filter, harmonic suppression, economical solution, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
More Details: System efficiency, power quality, and economic benefits have always been essential for the Unified Power Flow Controller (UPFC based on a Modular Multilevel Converter (MMC). This paper proposes a low-switching-frequency MMC-UPFC operation scheme based on the carrier phase shift pulse width modulation (CPS-PWM), which can significantly reduce switching loss and improve system efficiency. However, in medium-voltage MMC applications, the number of sub-modules in the UPFC is usually small (less than 30) exacerbating the harmonic distortions in the MMC-UPFC and reducing the switching frequency further deteriorates harmonics and increases capacitor voltage ripple. Therefore, to address the increased capacitor voltage ripple caused by low switching frequency, this paper proposes a reasonable carrier ratio (FR) design method. Analyzing and suppressing the capacitor voltage ripple at low switching frequencies can maintain capacitor voltage stability while significantly reducing the switching frequency. To address the issue of increased harmonics due to low switching frequency and few sub-modules, this paper combines the FR design method with an active LLCL filter method. An improved genetic algorithm is used to establish an objective function related to switching frequency harmonics and total inductance value, which can suppress a large number of high-order harmonics remaining from the CPS-PWM scheme, reduce the total inductance value, and compare this method with the single L filtering scheme widely used in UPFC engineering planning. Simulation on PLECS software verifies the effectiveness of the proposed method.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 2169-3536
Relation: https://ieeexplore.ieee.org/document/10758650/; https://doaj.org/toc/2169-3536
DOI: 10.1109/ACCESS.2024.3476143
Access URL: https://doaj.org/article/e48b0c92511e41a1815a99df5cd6ddfd
Accession Number: edsdoj.48b0c92511e41a1815a99df5cd6ddfd
Database: Directory of Open Access Journals
More Details
ISSN:21693536
DOI:10.1109/ACCESS.2024.3476143
Published in:IEEE Access
Language:English