Keywords: two-level voltage source converters, high voltage DC, HVDC transmission, multipulse, fundamental frequency switching, FFS, harmonics, power quality, quality improvement, bidirectional power flow
Power quality improvement in HVDC systems using 18-pulse voltage source converter
This paper deals with the modelling, control and design of 18-pulse voltage source converters (VSCs) for high voltage DC (HVDC) transmission system with power quality improvement. A two-level VSC is used to realise an 18-pulse VSC operation with minimum switching loss. The performance of the VSC system is improved in terms of reduced harmonics level at fundamental frequency switching (FFS). The performance of this converter is studied on various issues such as steady state operation, dynamic behaviour, reactive power compensation, power factor correction and harmonics distortion. Simulation results are presented for the designed two-level multipulse converters and the proposed control is used for bidirectional power flow.