Performance Enhancement of Voltage-Source-Converter Using Vector Control Under Load Disturbance

Voltage-source converter (VSC) -based transmission systems have attractive potential features in terms of power flow control and stability of the network. The increasing emergence of VSC-based transmission is the result of development in semiconductor devices, power electronic circuits, control, and executive engineering, The most important limiting factor of power semiconductors is their switching properties since they are usually optimized for the conduction intervals. This concept specifically proposes a control structure to improve the performance of high-power vector-controlled back-to-back VSC systems. The main improvement is to suppress the possible dc-link voltage fluctuations under power line faults and unbalanced conditions. The proposed controller structure is designed based on regulating the converter systems states locally in d-q synchronous reference frame without sequence components extraction or resonant notch compensator. The mat lab results verify the validity of the proposed control architecture during normal and unbalanced power system conditions. Index TermsHigh-voltage direct current (HVDC), Lyapunov methods, power systems faults, pulsewidth modulation (PWM) voltage source converter (VSC).