Jinke Li

TL;DR: The aim of this paper is to provide a comprehensive review of operation and control methods applied to MMC-HVdc systems with a specific focus on unbalanced ac-grid conditions.

TL;DR: In this paper, the authors investigated the impact of circulating current control in capacitor voltage ripples under different unbalanced ac grid conditions, while considering multiple control objectives and independent control of active and reactive power.

TL;DR: In this paper, the authors investigated and quantified the operating region of an MMC under unbalanced ac-grid conditions and the impact of circulating current control and system control targets on the limits of the MMC operating region.

TL;DR: In this paper, offset pulsewidth modulation (OPWM) and zero-sequence voltage injection were used to reduce the peak capacitance of the MMC under unbalanced ac-grid conditions.

TL;DR: In this paper, a novel circulating current-suppressing (CCS) fault-tolerant control strategy comprised of a basic control unit and virtual resistance compensation control unit (VRCCU) in two parts is proposed, which has three main features: (i) it can suppress the multi-different frequency components of the circulating current under different SM fault types simultaneously; (ii) it helps fast limiting of the transient fault current caused at the faulty SM bypassed moment; and (iii) it does not need extra communication systems to acquire the information of the number of faulty SM