Control Strategy of MMC-HVDC under Unbalanced Grid Voltage Conditions

- Journal title : Journal of Power Electronics
- Volume 15, Issue 6, 2015, pp.1499-1507
- Publisher : The Korean Institute of Power Electronics
- DOI : 10.6113/JPE.2015.15.6.1499

Title & Authors

Control Strategy of MMC-HVDC under Unbalanced Grid Voltage Conditions

Zhang, Jianpo; Zhao, Chengyong;

Zhang, Jianpo; Zhao, Chengyong;

Abstract

High voltage direct current transmission based on modular multilevel converter (MMC-HVDC) is one of the most promising power transmission technologies. In this study, the mathematical characteristics of MMC-HVDC are analyzed in a synchronous rotational reference frame. A hybrid current vector controller based on proportional integer plus resonant is used to uniformly control the DC and double-base frequency AC currents under unbalanced grid voltage conditions. A corresponding voltage dependent current order limiter is then designed to solve the overcurrent problems that may occur. Moreover, the circulating current sequence components are thoroughly examined and controlled using a developed circulating current suppressor. Simulation results verify the correctness and effectiveness of the proposed control schemes.

Keywords

Circulating current;HCVC;MMC;VDCOL;

Language

English

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