الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
With the recent developments in semiconductors and control equipment,
Voltage Source Converter based High Voltage Direct Current (VSC-HVDC) has
attracted the growing interest of researchers. The use of VSC technology and
Pulse Width Modulation (PWM) has a number of potential advantages: short
circuit current reduction; rapid and independent control of the active and reactive
power, etc. With such highly favorable advantages, VSC-HVDC is definitely
going to be a large part of future transmission and distribution systems. HVDC
technology based on VSC technology has been an area of growing interest
recently because of its suitability in forming a transmission link for transmitting
bulk amount of power.
This thesis deals with the control of VSC-HVDC. The objective of the work
is to understand the control structure of the VSC-HVDC system, and establish the
tuning criteria for the PI controllers of the converter controllers.
A model of a VSC based HVDC using PWM Technology is developed. A
mathematical model of the control system based on the relationships between
voltage and current is described for the VSC. A control system is developed
combining an inner current loop controller and outer dc voltage controller. The
vector control strategy is studied and corresponding dynamic performance under
step changes, system fault and the different methods to calculate the current
reference to control AC fault is investigated in MATLAB/SIMULINK simulation
package. The simulation results verify that the model can fulfill bi-directional
power transfers, fast response control and that the system has good steady state
performance. The controller parameters tuned according to the developed tuning
criteria is found to provide acceptable system performances.
The presented system is implemented using high-speed digital signal
processor (DSP1104). The total harmonic distortion THD improved from 17.5%
to 3.15% . Experimental results to depict the effectiveness of the proposed control
method of inverter are presented.