Fault-Tolerant Design and Control Strategy for Cascaded H-Bridge Multilevel Converter-Based STATCOM

2010 ◽  
Vol 57 (8) ◽  
pp. 2700-2708 ◽  
Author(s):  
Wenchao Song ◽  
A Q Huang
Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 876 ◽  
Author(s):  
Qinyue Zhu ◽  
Wei Dai ◽  
Lei Guan ◽  
Xitang Tan ◽  
Zhaoyang Li ◽  
...  

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.


2020 ◽  
Vol 10 (20) ◽  
pp. 7021
Author(s):  
Yan Li ◽  
Peng Xiang ◽  
Yandong Chen

This article proposes a topology of the secondary reconfigurable inverter and the corresponding fault-tolerant control strategy. When the secondary reconfigurable inverter is operating normally, its topology structure is the TPSS circuit. When the power semiconductor devices in the inverter are faulty, the inverter circuit needs to be reconfigured. After removing the faulty power semiconductor devices, the remaining power semiconductor devices and the DC side powers are reconstructed as the TPFS structure to keep the system running normally. This article also proposes a switch-pulse-resetting algorithm. This paper adopts the control strategy connecting the constant-voltage, constant-frequency control method with the switch pulse resetting algorithm. It need not change the control algorithm when the proposed reconfigurable inverter is transformed from the normal running state into the faulty running state. The inverter dependability is greatly improved. Finally, the feasibility and effectiveness of the proposed second reconfigurable inverter topology and control strategy are verified by simulation and experiment.


2021 ◽  
Vol 23 (3) ◽  
pp. 221-228
Author(s):  
Raaed Faleh Hassan ◽  
Suha Sabah Shyaa

In recent decades, multi-level converters have become popular and used in many power systems applications. Compared with conventional converters, multi-level converters contribute to reducing the voltage stress on the switching devices and enhancing the power quality delivered to the load. In this paper, the study of the five-level diode clamped multilevel converter based static synchronous compensator has been accomplished. Model Predictive current control strategy which a type of modern control algorithms was employed for driving the proposed compensator. The suggested five level converter controlled by model predictive current control is firstly examined to verify that this control algorithm is appropriate for achieving the desired performance. Then the proposed converter and control combination is employed and simulated as a static synchronous compensator in distributed power system. Moreover, in order to examine the robustness of this compensator, the load status is suggested to be heavy inductive. Simulation process has been performed using MATLAB – SIMULINK software package. The results show that the implemented configuration (converter and control algorithm) provides high power quality improvement with adequate reactive power compensation.


2013 ◽  
Vol 748 ◽  
pp. 510-513
Author(s):  
Hong Zheng ◽  
Yue Lei Shi ◽  
Hang Hui Zhang

f the ratio of NPC/H and H bridge hybrid multilevel converters DC supply voltage changed, the output voltage PWM waveform will be discontinuous. Thus an improved topology and control strategy is proposed. In new method, master converter operates at the fundamental frequency based on command voltage, slave converter adopts carrier phase shifted PWM technology (CPS-SPWM) at a higher frequency to enhance the quality of output voltage waveform. The amplitude of command voltage is higher than output voltage amplitude of the master converter at any time, to ensure that output voltage variation of both converters keeps in the same direction without any current flow backwards. Matlab simulation results demonstrate the effectiveness of the proposed control strategy and topology.


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