Start control of an M^3C-based FFTS

• Main Authors: Xiaoliang Zhang, Xifan Wang, Xiuli Wang, Qihang Huang, Jiajie Fan, Qian Zhou
• Format: Article
• Language: English
• Published: Wiley 2019-04-01
• Series: The Journal of Engineering
• Subjects: AC-AC power convertors; resistors; equivalent circuits; power transmission control; fractional frequency transmission system; transmission capacity; modular multilevel matric converter; self-start control strategy; start-up procedure; uncontrollable stage; controllable stage; digital simulation system; AC-AC converter; M^3C-based FFTS; AC transmission system reactance reduction; equivalent circuit; maximum charging current; current-limit resistor
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8401
• ISSN: 2051-3305

The fractional frequency transmission system (FFTS) can multiply increase transmission capacity by using a lower frequency to reduce the reactance of the AC transmission system. The modular multi-level matric converter (M^3C) as the new generation of the AC/AC converter is the critical equipment of FFTS. The self-start control strategy for M^3C-based FFTS is proposed and the whole start-up procedure is divided into the uncontrollable stage and controllable stage. The model of the equivalent circuit in an uncontrollable stage is built and the mathematical relation between the maximum charging current and the current-limit resistor is obtained. Finally, a digital simulation system of M^3C-based FFTS is established, and the effectiveness of the proposed control strategies is verified by simulation results.