DC/DC Converters Based on Hybrid MMC for HVDC Grid Interconnection

• Published in: 11th IET International Conference on AC and DC Power Transmission p. 065
• Main Authors: Zeng, Rong, Xu, Lie, Yao, Liangzhong
• Format: Conference Proceeding
• Language: English
• Published: Stevenage, UK IET 2015; The Institution of Engineering & Technology
• Subjects: d.c. transmission; DC-DC power convertors; Power system management, operation and economics; Switchgear; hybrid MMC topology; faulty DC grid section; Simulink; DC-DC power convertors; fault isolation; healthy DC grid sections; HVDC power transmission; multiterminal high-power DC-DC converter configuration; DC-DC converter terminal; step-up operation; bidirectional power flow; step-down operation; power system interconnection; power transmission faults; DC circuit breaker; modular multilevel converter; circuit breakers; fault blocking capability; power grids; HVDC grid interconnection; Matlab
• ISBN: 1849199825; 9781849199827
• DOI: 10.1049/cp.2015.0090

This paper presents a multi-terminal high-power DC/DC converter configuration based on hybrid MMC topology with fault blocking capability for interconnecting HVDC systems. Its main functions include bidirectional power flow, step-up and step-down operation and fault isolation equivalent to a DC circuit breaker. By contrast to the conventional MMC based DC/DC converter, the proposed DC/DC converter with hybrid MMC configuration has the advantage of being able to block the DC/DC converter terminal connecting to faulty DC grid section, while continue operating the other terminals connected to healthy DC grid sections. The proposed DC/DC converter operation is analyzed and its control is described. Simulation results using Matlab/Simulink are presented to demonstrate the robust performance during dc fault conditions.