Harmonic mitigation in voltage source converters based HVDC system using 12-pulse AC-DC converters

This paper investigates a 12-pulse voltage source converter (VSC) for harmonics mitigation in high voltage DC (HVDC) system. The most promising features of the VSC based system are compact and light weight design, short installation and commissioning periods, low operation and maintenance cost and flexibility in control. A current multiplier approach is proposed in this paper inside the voltage control loop for power quality (PQ) improvement at AC mains. The proposed system is designed, modeled and its performance is simulated in MATLAB-SIMULINK environment. The simulated results are presented to demonstrate an improved power quality at the AC mains in term of total harmonic distortion and power factor of the VSC based HVDC system under various transient conditions such as variation of load, load unbalancing and voltage sag in power supply.