학술논문
A DC Fault Ride-Through Control of Half-Bridge MMCs for the HVDC Grid with DC Circuit Breakers
Document Type
Conference
Author
Source
2022 International Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia) Power Electronics Conference (IPEC-Himeji 2022- ECCE Asia), 2022 International. :2046-2051 May, 2022
Subject
Language
Abstract
Operation delay of DC circuit breakers causes a voltage sag of several milliseconds in HVDC grids. The DC voltage sag may cause an overcurrent in the DC side of the modular multilevel converter (MMC), resulting in the halt of the MMC. This study investigates a method for enabling continuous operation of the half-bridge MMC during the DC voltage sag. The proposed method performs feedback control of the DC current during DC voltage sags by decreasing the DC and AC voltages of the half-bridge MMC. When the method is applied to symmetrical monopole HVDC systems, the MMC can maintain both its DC and AC currents within the rated range during the voltage sag caused by pole-to-ground faults. Simulation results obtained by a three-terminal HVDC grid verify the DC fault ride-through capability of the half-bridge MMC.