CSEE Journal of
Power & Energy Systems

Voltage source converter based high voltage direct current transmission (VSC-HVDC) is considered one of the most suitable technologies to integrate renewable energies. However, connecting VSC to a weak grid is challenging since traditional vector control tends to become unstable under high power demand conditions. In this paper, an improved vector control method is proposed wherein a feed forward ...

This paper introduces several key techniques in realtime digital simulation for closed-loop testing of high voltage direct current (HVDC) systems, including line commutated converter (LCC) HVDC valve group models, modular multilevel converter (MMC) HVDC models, phase domain frequency dependent transmission line models, and switchable filter models. Various issues such as background, algorithms, im...

A control strategy of frequency self-adaptation without phase-locked loop (PLL) under αβ stationary reference frame (αβ-SRF) for a VSC-HVDC system is presented to improve the operational performance of the system under severe harmonic distortion conditions. The control strategy helps to eliminate the cross-coupling under dq synchronous reference frame (dq-SRF), and ...

In view of the DC fault current isolation deficiency for the conventional half-bridge sub-module (HBSM) based modular multilevel converter (MMC), this paper presents an improved MMC topology. Both quasi reverse blocking submodules (QRBSMs) and current limit modules (CLMs) are employed to improve the DC fault handling capability for HVDC applications. This paper analyzes such a new converter config... 

This paper presents an isolated DC/AC/DC converter using a middle frequency transformer coupling two modular multilevel converters (MMC), suitable for interconnecting DC transmission lines of different voltage levels in high voltage direct current (HVDC) system. The basic operational principle of the isolated module multilevel DC/DC converter (IMMDCC) is analyzed. The dynamic model of IMMDCC is st...