DC fault ride through operation of a full-bridge MMC converter

In recent years the growth of renewable energy has encouraged the development of HVDC grids. One challenge of building HVDC grids is the power converter response to DC side faults. The full-bridge Modular Multilevel Converter (MMC) is a desired power converter topology which is used in HVDC grids du...

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Bibliographic Details
Main Author: Feng, Yixue
Format: Thesis (University of Nottingham only)
Language:English
Published: 2016
Online Access:https://eprints.nottingham.ac.uk/32426/
Description
Summary:In recent years the growth of renewable energy has encouraged the development of HVDC grids. One challenge of building HVDC grids is the power converter response to DC side faults. The full-bridge Modular Multilevel Converter (MMC) is a desired power converter topology which is used in HVDC grids due to its scalability, modularity and capability of blocking DC side faults. Post fault operation of the full-bridge MMC requires the control of power flow, the energy of each sub-module capacitor and the elimination of circulating harmonic current to reduce power loss while DC line-to-ground or DC line-to-line faults exist. This thesis presents a post fault operation method for a full-bridge MMC in order to transmit partial power after a DC line-to-ground fault and provides reactive power after DC line-to-line fault. Simulated results are provide from a point-to-point HVDC system which consists of two eleven-level full-bridge MMC.