scholarly journals Generic Analysis Framework for Modular Multilevel Converter HVDC with Multi-Infeed Line-Commutated Converter HVDC System

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 184
Author(s):  
Sehyun Kim ◽  
Kyeon Hur ◽  
Jongseo Na ◽  
Jongsu Yoon ◽  
Heejin Kim
Keyword(s):  
Power System ◽  
Reactive Power ◽  
Modulation Index ◽  
Modular Multilevel Converter ◽  
Analysis Framework ◽  
Multilevel Converter ◽  
Power Requirement ◽  
Hvdc System ◽  
Power Capability ◽  
Generic Analysis

This paper proposes a generic analysis framework for a grid supporting modular multilevel converter (MMC)-high voltage DC (HVDC) in a multi-infeed of line commutated converter (LCC) and MMC (MILM) system. MMC-HVDC can support the grid by compensating for the exact reactive power consumptions within the MMC-HVDC system and the varying power system conditions in the MILM system. Maximum active/reactive power capability (MPQC) curve and PQ loading curve comparison process is introduced to properly design a grid supporting MMC-HVDC. While the MPQC curve presents the maximum PQ range of the MMC-HVDC system based on the submodule capacitance value and the modulation index, the PQ loading curve presents the reactive power requirement from the power system that MMC-HVDC needs to compensate. Finally, the comparison of these two curves yields the proper value of submodule capacitance and the modulation index for sufficiently supporting the MILM system. The proposed framework is validated with detailed PSCAD/EMTDC simulation; it demonstrated that it could be applied to various power system conditions.

Modeling and Simulation of Modular Multilevel Converter Based-HVDC Connecting to Offshore Wind Farms

2014 ◽  
Vol 905 ◽  
pp. 421-426 ◽  
Author(s):  
Seung Hyun Kim ◽  
Woo Cheol Jeong ◽  
Eel Hwan Kim
Keyword(s):  
Wind Farm ◽  
Reactive Power ◽  
Control Method ◽  
Wind Farms ◽  
Offshore Wind ◽  
Voltage Source ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Offshore Wind Farms ◽  
Hvdc System

Modular multilevel Converter (MMC) is a new type of voltage source converter (VSC) topology. The use of this converter in a high-voltage direct current (HVDC) system is called by a MMC-HVDC system. The MMC-HVDC has the advantage in terms of scalability, performance, and efficiency over two-and three-level VSC-HVDC. In this paper, the MMC-HVDC system is used to connect between main grid in Jeju Island and virtual offshore wind farms. The aim is to transfer the power from offshore wind farm to the main grid and to compensate reactive power for the main grid. The simulation is carried out by using PSCAD/EMTDC program, and the results will confirm the effectiveness of the proposed control method.

scholarly journals Real Time Simulation of Wind Farm Connected MMC-HVDC System

2020 ◽  
Vol 8 (6S) ◽  
pp. 46-52
Keyword(s):  
Real Time ◽  
Wind Farm ◽  
Computing Time ◽  
Offshore Wind ◽  
Modular Multilevel Converter ◽  
Offshore Wind Farm ◽  
Multilevel Converter ◽  
Real Time Simulation ◽  
Hvdc System ◽  
Time Simulation

Real time simulators play a major role in R&D of Offshore wind farm connected modular multilevel converter (MMC)-HVDC system. These simulators are used for testing the actual prototype of controllers or protection equipment required for the system under study. Modular multilevel converter comprises of number of sub modules (SMs) like Half/ full bridge cells. While computing time domain Electromagnetic transients (EMTs) with the system having large number of SMs pose a great challenge. This computational burden will be more when simulated in real time. To overcome this, several authors proposed equivalent mathematical model of MMC. This paper proposes the real time simulation start-up of offshore wind farm connected modular multilevel converter (MMC)-HVDC system. This paper also describes about how the above said systems is simulated in OPAL-RT based Hypersim software.

scholarly journals Voltage Ride through Control Strategy of Modular Multilevel Converter under Unbalanced Voltage Sag

2019 ◽  
Vol 9 (3) ◽  
pp. 551
Author(s):  
Seyed Hakimi ◽  
Amin Hajizadeh
Keyword(s):  
Control Strategy ◽  
Reactive Power ◽  
Current Control ◽  
Adaptive Robust Control ◽  
Voltage Sag ◽  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Control Approach ◽  
Control Loops ◽  
Unbalanced Voltage

This paper develops modeling and describes a control strategy for a modular multilevel converter (MMC) for grid-connected renewable energy systems. The proposed model can be used to simulate MMC activity during normal and faulty situations. Firstly, a dynamic model of a grid-connected MMC (GC-MMC), based upon the symmetrical component of voltages and currents, was designed. Then an adaptive robust control approach was established in order to follow the reference currents of the converter and stabilize the submodule (SM) capacitor voltage. The positive and negative sequences of reference currents that were given from the demanded active and reactive power during grid voltage disturbance and a normal situation were then utilized in control loops. Finally, the numerical results for the performance of the MMC throughout voltage sag conditions and the effect of uncertainties on the filter parameters during changing power demands were evaluated. The results specified that the current control strategy is more potent under voltage sag situations and able to fulfill the stability requirements of the MMC.

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.

The Research Status of Modular Multilevel Converter and its Capacitor Voltage Balancing Control

2014 ◽  
Vol 535 ◽  
pp. 153-156
Author(s):  
Ya Ai Chen ◽  
Peng Chen ◽  
Jing Hua Zhou
Keyword(s):  
Modular Multilevel Converter ◽  
Multilevel Converter ◽  
Topology Structure ◽  
Voltage Balancing ◽  
Research Status ◽  
Hvdc System ◽  
Capacitor Voltage ◽  
Working Principle ◽  
Balancing Control

The thesis mainly analyzes the topology structure and the working principle of MMC based VSC-HVDC system; introduces the characteristics and research status of its capacitor voltage balancing control. All of this will lay a foundation for the further research.

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