Capacitance health monitoring in the modular multilevel converter using a method with minimum number of sensors and computational burden

• Published in: International journal of circuit theory and applications 2024-12, Vol.52 (12), p.6343-6361
• Main Authors: Zoraghi‐Jedi, Mahsa, Barakati, Seyed‐Masoud, Rahmani‐Haredasht, Mohsen, Barahouei, Vahid, Yazdani, Amirnaser
• Format: Article
• Language: English
• Subjects: Capacitance; capacitance health monitoring (CHM); Capacitors; Data exchange; Electric potential; Microprocessors; modular multilevel converter (MMC); reliability; Sensors; Voltage; voltage sensor
• ISSN: 0098-9886; 1097-007X
• DOI: 10.1002/cta.4057

Summary This paper proposes a method for capacitance health monitoring (CHM) of submodule capacitors in modular multilevel converters (MMCs) that uses a reduced number of voltage sensors. In the proposed method, the MMC arms are divided into some groups of submodules and one voltage sensor is used for each group. In addition, a capacitor voltage estimation technique with minimal computational complexity is used to determine the capacitor voltage. The ratio of the estimated to measured capacitor voltage during positive arm current is also used to demonstrate a simple and efficient capacitance monitoring method. Moreover, contrary to the limitations associated with traditional CHM methods, the proposed method reduces the required voltage sensors and minimizes data exchange between the power system and the central processor. The effectiveness of the proposed method is validated through simulation and experimental results under various operating conditions. Efficient CHM for MMCs is achieved with the proposed method, utilizing grouped sub‐modules and minimal voltage sensors. The proposed method offers a simplified capacitor voltage estimation technique, reducing computational complexity and enhancing monitoring efficiency. Simulation and experimental validations show the effectiveness under diverse operating conditions.