scholarly journals Fast compensation of DC bus voltage drops using modular multilevel converters

2019 ◽  
Vol 2019 (17) ◽  
pp. 3906-3911 ◽  
Author(s):  
Christoph Stark ◽  
Dierk Danowski ◽  
Jose-Luis Marqués ◽  
Claus Hillermeier
Keyword(s):  
Multilevel Converters ◽  
Voltage Drops ◽  
Modular Multilevel Converters ◽  
Dc Bus ◽  
Bus Voltage

Control of Grid Voltage Feed-Forward and Crowbar Circuit for DC-Bus Voltage

2014 ◽  
Vol 875-877 ◽  
pp. 1723-1728
Author(s):  
Xi Yun Yang ◽  
Li Xia Li ◽  
Ya Min Zhang ◽  
Jin Gao
Keyword(s):  
Power System ◽  
Wind Power ◽  
Output Power ◽  
Stability Control ◽  
Grid Voltage ◽  
Voltage Drops ◽  
Wind Power System ◽  
Dc Bus ◽  
Bus Voltage ◽  
The Stability

The DC bus voltage is the main criteria to reflect whether the converter system is working properly or not, and the stability control of the DC bus voltage is the key to ensure that wind power generators not take off the grid when grid voltage drops. This paper had done research on a direct-drive wind power system and proposed a coordinated control method based on the grid voltage information feedforward with a crowbar circuit. The hardware was combined with the improved control strategy in this method. When the grid voltage drops, the extra energy of the DC bus can be unleashed by the crowbar circuit, at the same time, the output power of motor-side can be controlled according to the grid-side information, and the mechanical speed of motor-side can be suppressed by the pitch angle regulation when the output power reduces. Thus, the DC-bus voltage can be keep stability. Results based on Matlab/Simulink simulation shows that this method not only improves the stability and dynamic response performance of the DC bus voltage, but also effectively maintains the output power of generator and reduces the action time of crowbar circuit. The ability of the wind power system riding through the grid fault has been effectively improved.

scholarly journals New Optimized Control of Cascaded Multilevel Converters for Grid Tied Photovoltaic Power Generation

2021 ◽  
Vol 54 (5) ◽  
pp. 769-776
Author(s):  
Karima Benamrane ◽  
Thameur Abdelkrim ◽  
Benlahbib Benlahbib ◽  
Noureddine Bouarroudj ◽  
Abdelhalim Borni ◽  
...  
Keyword(s):  
Duty Cycle ◽  
Fuzzy Logic Controller ◽  
Pulse Width Modulation ◽  
Multilevel Converters ◽  
Pi Regulator ◽  
Duty Cycles ◽  
Dc Bus ◽  
Bus Voltage ◽  
Two Stages

This paper proposes a new optimized control of photovoltaic two stages conversion cascade composed by Three Levels Boost (TLB) and Three Levels Neutral Point Clamped (TLNPC) inverter. In order to extract the maximum power from photovoltaic generator and get a balanced DC bus voltage, the duty cycles of the two TLB switches are determinate from a Fuzzy Logic Controller (FLC) for the first switch and by adding to the first duty cycle an additional duty cycle obtained by integration of the error between the two capacitors voltages of DC bus. Balancing the bus voltages by the TLB using a single regulator avoid us to use a complex balancing algorithm by the redundant vectors of TLNPC inverter. For the control of the inverter, we used a Proportional Integral (PI) regulator optimized by PSO. This command allows us to have on one side a constant DC bus voltage and a current injection in phase with the grid voltage. To have an efficient follow-up of the TLNPC inverter reference voltages, the Space Vector Pulse Width Modulation (SVPWM) is applied. The simulation is carried out in MATLAB/SIMULINK platform. The results obtained from the application of the FLC command associated with PI PSO are better compared to the simulation without optimization in terms of sum of the absolute values of the errors at the inputs of the three PI regulators.

scholarly journals Fault Simulations in a Multiterminal High Voltage DC Network with Modular Multilevel Converters Using Full-Bridge Submodules

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1653
Author(s):  
Ioan-Cătălin Damian ◽  
Mircea Eremia ◽  
Lucian Toma
Keyword(s):  
High Voltage ◽  
Energy Resource ◽  
Fault Analysis ◽  
Renewable Energy Resource ◽  
Dynamic Simulations ◽  
Multilevel Converters ◽  
Strong Focus ◽  
Modular Multilevel Converters ◽  
Overhead Power Lines ◽  
And Control

The concept of high-voltage DC transmission using a multiterminal configuration is presently a central topic of research and investment due to rekindled interest in renewable energy resource integration. Moreover, great attention is given to fault analysis, which leads to the necessity of developing proper tools that enable proficient dynamic simulations. This paper leverages models and control system design techniques and demonstrates their appropriateness for scenarios in which faults are applied. Furthermore, this paper relies on full-bridge submodule topologies in order to underline the increase in resilience that such a configuration brings to the multiterminal DC network, after an unexpected disturbance. Therefore, strong focus is given to fault response, considering that converters use a full-bridge topology and that overhead power lines connect the terminals.

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