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 multipulse converter to
demonstrate its capability. The control algorithm is disused in detail for operating
the converter at fundamental frequency switching.
KEYWORDS
Two-Level
Voltage Source Converter, HVDC Systems, Multipulse, Fundamental Frequency
Switching, Harmonics.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1 A 48-Pulse voltage source converter based HVDC system configuration
EXPECTED SIMULATION RESULTS:
Fig.
2 Steady state performance of proposed 48-pulse voltage source converter
Fig.
3 Dynamic performance of proposed 48-pulse voltage source converter
Fig.
4 Waveforms and harmonic spectra of 48-pulse covnerter (a) supply voltage (b)
supply current (c) converter voltage
CONCLUSION
A 48-pulse two-level voltage source
converter has been designed, modeled and controlled for back-to-back HVDC system.
The transformer connections with appropriate phase shift have been used to
realize a 48-pulse converter along with a control scheme using a set of two
level six pulse converters. The operation of the designed converter
configuration has been simulated and tested in steady sate and transient conditions
which have demonstrated the quite satisfactory converter operation. The
characteristic harmonics of the system has also improved by the proposed
converter configuration.
REFERENCES
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[3] Y. H. Liu R. H. Zhang, J. Arrillaga
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