DC-Bus Voltage Sensorless Control of an Active Rectifier with Modular Multilevel Converter

• Published in: Energies (Basel) Vol. 16; no. 18; p. 6569
• Main Authors: Pan, Jianyu, Du, Yihao, Ke, Ziwei
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-09-2023
• Subjects: active rectifier; Algorithms; Analysis; capacitor pre-charging; Charged particles; Costs; Electric current converters; Fault tolerance; Ions; Methods; modular multilevel converter (MMC); Power supply; sensorless control; Sensors; China; Beijing China
• ISSN: 1996-1073; 1996-1073
• DOI: 10.3390/en16186569

The modular multilevel converter (MMC) is recognized as one of the promising converters for the electrification of ships and railways. Among different energy conversion stages, the MMC-based rectifier should realize stable DC output voltage and accurate input current control. However, output DC-bus voltage sensors must be installed, which are costly and bulky. This paper presents a simple but effective control method for the MMC-based rectifier, removing the traditional output DC-bus voltage sensor. An accurate evaluation model of DC-bus voltage is developed as well as the implementing method. Meanwhile, a safe and fast pre-charging scheme is presented for the MMC-based rectifier without output voltage sensors. The fault-tolerant capability of the proposed method when the failure of the output DC-bus voltage sensor occurs is examined. Simulated and testing results demonstrate that the proposed method presents not only excellent steady-state and dynamic performance but also strong fault-tolerant capability. The proposed evaluation model for DC-bus voltage has a high accuracy with an error of less than 1%. Besides, the pre-charging time is less than 0.5 s using the proposed sensorless control.