Improved Thevenin Equivalent Model of MMC Considering Pre-charge Conditions and DC Side Fault Conditions

2021 ◽  
Vol 36 (6) ◽  
pp. 796-805
Author(s):  
Enshu Jin ◽  
Zhenyu Song ◽  
Xiaofan Yang ◽  
Xin Yu
Keyword(s):  
Working Conditions ◽  
Control Strategy ◽  
Equivalent Model ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Detailed Model ◽  
Comparison And Analysis ◽  
Simulation Results ◽  
Thevenin Equivalent ◽  
Model Topology

The traditional Thevenin equivalent Modular Multilevel Converter (MMC) model has poor versatility for the two working conditions of pre-charging and DC-side faults. In this paper, an improved Thevenin equivalent MMC model considering pre-charge conditions and DC side fault conditions is proposed. The model divides the pre-charging condition into a Controllable charging stage and an Uncontrollable charging stage. The DC-side fault condition is divided into the pre-blocking and post-blocking conditions of the converter. The circuit characteristics are analyzed, and the equivalent model topology is comprehensively improved to make it suitable for full-condition simulation, and a control strategy suitable for the equivalent model is proposed. The detailed model and the proposed improved equivalent model were built in PSCAD/EMTDC for comparison and analysis. The simulation results shows that the improved equivalent model can be applied to various working conditions, and the versatility of the traditional Thevenin equivalent model is improved.

A linearized small-signal Thévenin-equivalent model of a voltage-controlled modular multilevel converter

2020 ◽  
Vol 182 ◽  
pp. 106231 ◽  
Author(s):  
Cleiton Magalhães Freitas ◽  
Edson Hirokazu Watanabe ◽  
Luís Fernando Corrêa Monteiro
Keyword(s):  
Equivalent Model ◽  
Small Signal ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Thevenin Equivalent

scholarly journals Research on Precharge Control Strategy of Modular Multilevel Inverter

2021 ◽  
Vol 261 ◽  
pp. 02039
Author(s):  
Chuanliang Fang ◽  
Guochu Chen
Keyword(s):  
Control Strategy ◽  
Multilevel Inverter ◽  
Modular Multilevel Converter ◽  
Simulation Environment ◽  
Multilevel Converter ◽  
Simple Analysis ◽  
Simulink Simulation ◽  
Working Principle ◽  
Simulation Results ◽  
The Mathematical Model

This paper mainly introduces the Modular Multilevel Converter (MMC) topology structure, simple analysis of the working principle of MMC, deduced the mathematical model of MMC. The precharging control strategy of MMC sub-module (SM) is studied, and the charging process is divided into uncontrollable charging stage and controllable charging stage. For the uncontrollable charging stage, an improved DC side pre-charging method is proposed, and a five-level simulation model of voltage-type MMC is established in the Matlab/Simulink simulation environment, and the simulation results of the system are comprehensively analyzed.

scholarly journals Series Active Filter Design Based on Asymmetric Hybrid Modular Multilevel Converter for Traction System

Electronics ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 134 ◽  
Author(s):  
Muhammad Ali ◽  
Muhammad Khan ◽  
Jianming Xu ◽  
Muhammad Faiz ◽  
Yaqoob Ali ◽  
...  
Keyword(s):  
Low Voltage ◽  
Filter Design ◽  
Switching Frequency ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Medium Voltage ◽  
Converter Topologies ◽  
Asymmetric Hybrid ◽  
Simulation Results ◽  
Traction System

This paper presents a comparative analysis of a new topology based on an asymmetric hybrid modular multilevel converter (AHMMC) with recently proposed multilevel converter topologies. The analysis is based on various parameters for medium voltage-high power electric traction system. Among recently proposed topologies, few converters have been analysed through simulation results. In addition, the study investigates AHMMC converter which is a cascade arrangement of H-bridge with five-level cascaded converter module (FCCM) in more detail. The key features of the proposed AHMMC includes: reduced switch losses by minimizing the switching frequency as well as the components count, and improved power factor with minimum harmonic distortion. Extensive simulation results and low voltage laboratory prototype validates the working principle of the proposed converter topology. Furthermore, the paper concludes with the comparison factors evaluation of the discussed converter topologies for medium voltage traction applications.

scholarly journals A Simple and Novel Precharging Control Strategy for Modular Multilevel Converter

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 170500-170512 ◽  
Author(s):  
Wentao Liu ◽  
Ke-Jun Li ◽  
Zhijie Liu ◽  
Meiyan Wang
Keyword(s):  
Control Strategy ◽  
Modular Multilevel Converter ◽  
Multilevel Converter

scholarly journals A Fault-Tolerant Control Strategy of Modular Multilevel Converter with Sub-Module Faults Based on Neutral Point Compound Shift

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 876 ◽  
Author(s):  
Qinyue Zhu ◽  
Wei Dai ◽  
Lei Guan ◽  
Xitang Tan ◽  
Zhaoyang Li ◽  
...  
Keyword(s):  
Fault Tolerance ◽  
Control Strategy ◽  
Control Method ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Neutral Point ◽  
Modular Multilevel Converter ◽  
Phase Voltage ◽  
Multilevel Converter ◽  
Shift Control

In view of the complex calculation and limited fault tolerance capability of existing neutral point shift control algorithms, this paper studies the fault-tolerant control method for sub-module faults in modular multilevel converters on the basis of neutral point compound shift control strategy. In order to reduce the calculation complexity of shift parameters in the traditional strategy and simplify its implementation, an improved AC side phase voltage vector reconstruction method is proposed, achieving online real-time calculation of the modulation wave adjustment parameters of each phase required for fault-tolerant control. Based on this, a neutral point DC side shift control method is proposed to further improve the fault tolerance capability of the modular multilevel converter (MMC) system by compensating the fault phase voltage with non-fault phase voltage. By means of the compound shift control strategy of the DC side and AC side of the neutral point, an optimal neutral point position is selected to ensure that the MMC system output line voltage is symmetrical and the amplitude is as large as possible after fault-tolerant control. Finally, the effectiveness and feasibility of the proposed control strategy are verified by simulation and low-power MMC experimental system testing.

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