Abstract
The voltage source converter based high voltage direct current (VSC-HVDC) technology has attracted much attention in recent years for its beneficial characteristics. The VSC-HVDC system is sensitive to voltage unbalance. However, voltage unbalance may occur in the three-phase power system frequently, due to unbalanced power supply, unbalanced loads and faults in AC system. It may require that the VSC-HVDC system continues to function even under unbalanced conditions. Without dedicately designed controllers, the second harmonic voltage will appear on the DC bus. It increases the losses and may result in system instability. In the paper, a simple and effective control scheme is presented to improve the dynamic performances of VSC-HVDC system under unbalanced conditions. The controllers are implemented in two synchronous reference frames (SRFs), namely the positive and negative SRFs, which rotate counterclockwise and clockwise. In addition, a new fast sequence components separation technique is also proposed. The simulation results show that the proposed control scheme performs well under both balanced and unbalanced conditions.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.