scholarly journals Virtual control method applied to Modular Multilevel Converter

2021 ◽  
Author(s):  
Zitao Zhang ◽  
Chuyang Wang ◽  
Yang Xu
Keyword(s):  
Control Method ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Virtual Control

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.

Research on the Control Method of STATCOM Based on MMC

2013 ◽  
Vol 448-453 ◽  
pp. 2167-2170
Author(s):  
Kai Li ◽  
Yi Hui Zheng ◽  
Xin Wang ◽  
Li Xue Li ◽  
Gang Yao ◽  
...  
Keyword(s):  
Closed Loop ◽  
Reactive Power ◽  
Control Method ◽  
Modular Multilevel Converter ◽  
Energy Balancing ◽  
Multilevel Converter ◽  
Voltage Fluctuation ◽  
Loop Control ◽  
Voltage Balancing ◽  
High Voltage Direct Current

To realize the STATCOM based on Modular Multilevel Converter (MMC), a simplified double-closed loop structure, simplifying from the control method of High Voltage Direct Current (HVDC) based on MMC, is presented. Considering MMCs DC side using capacitors, a part-controlling method based on energy balancing is proposed, to solve the voltage balancing problem. With the part-controlling fixing the changing capacitors voltage and the simplified double-closed loop control method, voltage fluctuation could be reduced, and the loads reactive power could be compensated. The correctness and the effectiveness of the MMC-STATCOM controlling scheme is verified by Matlab/Simulink.

scholarly journals Novel Uninterruptible Phase-Separation Passing and Power Quality Compensation Scheme Based on Modular Multilevel Converter for Double-Track Electrified Railway

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 738
Author(s):  
Xu Tian ◽  
Xingcheng Li ◽  
Zibo Zhou
Keyword(s):  
Phase Separation ◽  
Power Systems ◽  
Power Quality ◽  
Control Method ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Electrified Railway ◽  
Uninterruptible Power ◽  
Negative Sequence Current ◽  
Double Track

Over-voltage and over-current problems of locomotives when passing phase separation and negative sequence current penetration seriously influence the safety of double-track electrified railway and public power systems. In order to solve these problems, this paper proposes a novel uninterruptible power supply phase separation passing and power quality compensation (UPSP-PQC) scheme for double-track electrified railway. Three working modes of UPSP-PQC are put forward, including uninterruptible phase separation passing mode, power quality compensation mode and uninterruptible phase separation passing priority, and power quality compensation optimum mode. A three-leg modular multilevel converter (MMC) topology of UPSP-PQC is proposed and the corresponding control strategy has been studied. PSCAD/EMTDC simulation is performed to verify the correctness and effectiveness of the proposed scheme and its control method.

scholarly journals Arm Power Control of the Modular Multilevel Converter in Photovoltaic Applications

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1620 ◽  
Author(s):  
Anirudh Budnar Acharya ◽  
Mattia Ricco ◽  
Dezso Sera ◽  
Remus Teodorescu ◽  
Lars Einar Norum
Keyword(s):  
Power Generation ◽  
Control Method ◽  
Maximum Power Point Tracking ◽  
Maximum Power ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Maximum Power Point ◽  
Point Tracking ◽  
Power Point Tracking ◽  
Power Point

In this paper, a control method is proposed that allows the extraction of maximum power from each individual photovoltaic string connected to the Modular Multilevel Converter (MMC) and inject balanced power to the AC grid. The MMC solution used does not need additional DC–DC converters for the maximum power point tracking. In the MMC, the photovoltaic strings are connected directly to the sub-modules. It is shown that the proposed inverter solution can provide balanced three-phase output power despite an unbalanced power generation. The maximum power of the photovoltaic string is effectively harnessed due to the increased granularity of the maximum power point tracking. An algorithm that tracks the sub-module capacitor voltages to their respective voltage references is proposed. A detailed modeling and control method for balanced operation of the proposed topology is discussed. The operation of the MMC under unbalanced power generation is discussed. Simulation results are provided that show the effectiveness of the proposed control under unequal irradiance.

A Novel STATCOM Based on Flying Capacitor Modular Multilevel Converter

2018 ◽  
Vol 6 (11) ◽  
pp. 86
Author(s):  
T. Sanjeeva Rao ◽  
T. Sowjanya
Keyword(s):  
Control Method ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Static Synchronous Compensator ◽  
Current Compensation ◽  
Negative Sequence ◽  
Capacitor Voltage ◽  
Voltage Balance ◽  
Capacitor Voltage Balance ◽  
Negative Sequence Current

A new static synchronous compensator (STATCOM) based on Flying Capacitor modular multilevel converter (DCM2C) is proposed in this thesis. In this converter topology the capacitor voltage is clamped by using a low power rating diode in each sub-module (SM). The quantity of voltage sensors is significantly reduced and is free from the number of voltage levels. Furthermore the voltage balancing control method becomes very simple and the capacitor voltage balance speed is fast. Based on the structure of MMC the DCM2C-STATCOM has the capability of Var compensation and negative sequence current compensation. The topology characteristics and compensation control method of DCM2C-STATCOM are investigated in this thesis. That the capacitor voltage of the proposed DCM2C-STATCOM can be well balanced and the Var and negative-sequence current compensation are effective.

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