26-05-2012, 03:01 PM
A TWO-LEVEL, 48-PULSE VOLTAGE SOURCE CONVERTER FOR HVDC SYSTEMS
ABSTRACT
This paper deals with an analysis, modeling and control of a two level 48-pulse voltage source converter for High Voltage DC (HVDC) system. A set of two-level 6-pulse voltage source converters (VSCs) is used to form a 48-pulse converter operated at fundamental frequency switching (FFS). The performance of the VSC system is improved in terms of reduced harmonics level at FFS and THD (Total Harmonic Distribution) of voltage and current is achieved within the IEEE 519 standard. The performance of the VSC is studied in terms of required reactive power compensation, improved power factor and reduced harmonics distortion. Simulation results are presented for the designed two level multi pulse converter to demonstrate its capability. In this multi pulse converter circuits the converter bridges are operated at fundamental frequency switching (FFS) thus reduce the switching losses substantially. Pulse number can be increased in multiples of six, and an increase in every six pulse VSC reduces the harmonics in the system proportionally. The control algorithm is disused in detail for operating the converter at fundamental frequency switching.
ABSTRACT
This paper deals with an analysis, modeling and control of a two level 48-pulse voltage source converter for High Voltage DC (HVDC) system. A set of two-level 6-pulse voltage source converters (VSCs) is used to form a 48-pulse converter operated at fundamental frequency switching (FFS). The performance of the VSC system is improved in terms of reduced harmonics level at FFS and THD (Total Harmonic Distribution) of voltage and current is achieved within the IEEE 519 standard. The performance of the VSC is studied in terms of required reactive power compensation, improved power factor and reduced harmonics distortion. Simulation results are presented for the designed two level multi pulse converter to demonstrate its capability. In this multi pulse converter circuits the converter bridges are operated at fundamental frequency switching (FFS) thus reduce the switching losses substantially. Pulse number can be increased in multiples of six, and an increase in every six pulse VSC reduces the harmonics in the system proportionally. The control algorithm is disused in detail for operating the converter at fundamental frequency switching.