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.

Research on VSC-HVDC Based on Modular Multilevel Converter Technique

2014 ◽  
Vol 577 ◽  
pp. 588-593
Author(s):  
Si Yu Chen ◽  
Ya Lou Li ◽  
Xiao Bo Hu ◽  
Li Zhao ◽  
Chao Xi Chen
Keyword(s):  
Theoretical Model ◽  
Equivalent Circuit ◽  
Control Strategy ◽  
Traditional Method ◽  
Experimental Results ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Hvdc System ◽  
Proposed Model ◽  
Working Principle

This paper introduces the topology and working principle of modular multilevel converter, simplifying its equivalent circuit before obtaining virtual equipotential. On the ground of the theoretical model of equivalent circuit, MMC-HVDC could adapt the same control strategy as the traditional method. So, on the platform of PSCAD/EMTDC, an eleven level MMC Dual-infeed HVDC system is established and nearest level modulation is adopted as its control strategy to sort voltage sharing of the modules. Experimental results prove the validity of the proposed model.

A Novel Three Phase Cascaded Multilevel Inverter

2013 ◽  
Vol 646 ◽  
pp. 249-258
Author(s):  
Sheng Wang ◽  
Jia Hua Zhong ◽  
Shao Dong Wang ◽  
Jin Ping He
Keyword(s):  
Control Strategy ◽  
Topological Structure ◽  
Output Voltage ◽  
Multilevel Inverter ◽  
Experimental Results ◽  
Phase System ◽  
Multilevel Converter ◽  
Three Phase ◽  
Simulation Results ◽  
Cascaded Multilevel Inverter

Based on the theory of H-bridge multilevel converter, the structure of a three phase cascaded multilevel inverter (LVCMI) and its control strategy are proposed in this paper. Several standard three-phase bridges can be reconnected into a new single three-phase bridge at ac-side. Simulation results show that such topological structure can increase the output voltage capacity and reduce the THD. It can be used as an inverter or rectifier in three phase system. In theory, it can be cascaded unlimitedly. The more cascaded, the higher output voltage and the lower THD. Experimental results of LVCMI with 3-module verified the feasibility of the proposed inverter.

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.

Research on Flux Damping Control Strategy of DFIG during Grid Voltage Dips

2015 ◽  
Vol 713-715 ◽  
pp. 756-759
Author(s):  
Xu Guang Zhang ◽  
Zhen Xie
Keyword(s):  
Mathematical Model ◽  
Control Strategy ◽  
Grid Voltage ◽  
Damping Control ◽  
Simulink Simulation ◽  
Voltage Dips ◽  
Simulation Results ◽  
Stator Flux ◽  
Natural Component ◽  
Simplified Mathematical Model

A flux damping control strategy was proposed to accelerate the decay of stator flux and restrain stator, rotor current and torque oscillation caused by grid voltage dips. Firstly, this paper analyzes the simplified mathematical model of DFIG during symmetrical voltage dips. Then, the mechanism of flux damping control strategy to restrain stator, rotor current oscillation and increase flux damping was analyzed. The flux damping control strategy can increase the damping of stator side, which accelerates the decay of the stator flux natural component and improve the dynamic LVRT performance of DFIG. The correctness and effectiveness of this method is verified by MATLAB/Simulink simulation results.

Control of inverters in standalone andgrid-connected microgrid using different control strategies

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vikash Gurugubelli ◽  
Arnab Ghosh
Keyword(s):  
Transient Response ◽  
Control Strategy ◽  
Control Strategies ◽  
Power Balance ◽  
Droop Control ◽  
Content Type ◽  
Simulink Simulation ◽  
Time Simulation ◽  
Simulation Results ◽  
First Time

Purpose The share of renewable energy sources (RESs) in the power system is increasing day by day. The RESs are intermittent, therefore maintaining the grid stability and power balance is very difficult. The purpose of this paper is to control the inverters in microgrid using different control strategies to maintain the system stability and power balance. Design/methodology/approach In this paper, different control strategies are implemented to the voltage source converter (VSC) to get the desired performance. The DQ control is a basic control strategy that is inherently present in the droop and virtual synchronous machine (VSM) control strategies. The droop and VSM control strategies are inspired by the conventional synchronous machine (SM). The main objective of this work is to design and implement the three aforementioned control strategies in microgrid. Findings The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy. Research limitations/implications In the power system, the power electronic-based power allowed by VSM is dominated by the conventional power which is generated from the traditional SM, and then the issues related to stability still need advance study. There are some differences between the SM and VSM characteristics, so the integration of VSM with the existing system still needs further study. Economical operation of VSM with hybrid storage is also one of the future scopes of this work. Originality/value The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy.

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
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