Four-Level Diode-Clamped Based Twenty-Four Pulse VSC for HVDC Converter Applications

This paper presents a 24-pulse voltage source converter (VSC) system for high voltage direct current (HVDC) application. The system utilizes four-level neutral point clamped (NPC4L) converters in conjunction with star-delta transformer configurations to achieve a 24-pulse operation, which significantly reduces harmonics distortion. Converters are modulated using fundamental frequency switching (FFS), ensuring efficient power conversion and grid integration. Performance of a 1000MW HVDC system is validated through simulations in MATLAB Simulink, demonstrating effective harmonics reduction, steady-state and dynamic operation, making it suitable for HVDC integration.