Selection methods of main circuit parameters for modular multilevel converters

Xu, Zheng; Xiao, Huangqing; Zhang, Zheren

doi:10.1049/iet-rpg.2015.0434

Cited by 72 publications

(39 citation statements)

References 11 publications

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“…However, according to the selection method of main circuit parameters for MMCs [29], H=40 ms is recommended. Additionally, the selection of the arm inductance must avoid the circulating current resonance, and L=0.2 pu is usually recommended with the considerations of security and economy.…”

Section: Controller Parameter Optimal Design For the Interconnectementioning

confidence: 99%

Optimal Design of Controller Parameters for Improving the Stability of MMC-HVDC for Wind Farm Integration

Lyu

Cai

Molinas

2018

IEEE J. Emerg. Sel. Topics Power Electron.

154

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Section: Controller Parameter Optimal Design For the Interconnectementioning

confidence: 99%

Optimal Design of Controller Parameters for Improving the Stability of MMC-HVDC for Wind Farm Integration

Lyu

Cai

Molinas

2018

IEEE J. Emerg. Sel. Topics Power Electron.

154

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“…To enable the decoupling of the active and reactive power in the hybrid system, we need to omit some secondary factors in the Jacobi matrix based on the steady-state characteristics of AC/DC grids. Given that the negative sequence voltage in the grid is confined to 1.5 % of the rated power, to ensure the long-term operation of VSCs, the negative sequence current through the converter reactor X l,i should be no larger than 5 %~10 % of the rated VSC current [12]. Thus, we have [13].…”

Section: State Estimation Model Of the Ac/dc Systemmentioning

confidence: 99%

Bad Data Detection and Identification of Hybrid AC/DC Power Systems with Voltage Source Converters Using Deep Belief Network and K-Means Clustering

Zhang¹,

Yu²,

Zhai³

et al. 2019

ElAEE

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The widespread use of Voltage Source Converter based High Voltage Direct Current Transmission (VSC-HVDC) technology has significantly increased the complexity of grid configuration and operation, which demands higher quality of AC/DC state estimation. The bad data detection and identification plays a vital role in ensuring the accuracy of state estimation outcomes. This paper presents a new approach to bad data in hybrid AC/DC grids based on the combined deep belief network (DBN) and K-means clustering method. First, the DBNs are trained separately for active and reactive power given the characteristics of VSC-HVDC by which the bad data can be detected. Then, an improved K-means is used for clustering the DBN outputs by setting the mean and the number of the samples within the clusters as two metrics for bad data identification. Finally, the case study is performed in a modified IEEE 14-bus system and the results demonstrate the effectiveness of the proposed method in terms of both the accuracy and efficiency.

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“…However, choosing large capacitance will lead to high project cost and occupy a large area. Usually the appropriate capacitance should limit the capacitor voltage fluctuation ratio below 10%-15% [29]. Therefore, the calculation of the capacitor voltage is vital in the capacitor sizing.…”

Section: Capacitor Sizing For the MMC Connected To Pmsgmentioning

confidence: 99%

“…where, u cap.dc is the DC component and ∆u cap (t) is the fluctuation component. Then, the capacitor voltage fluctuation ratio ε can be defined as follows [29]:…”

Section: Capacitor Sizing For the MMC Connected To Pmsgmentioning

confidence: 99%

“…This kind of methods avoids deducing the equation of capacitor voltage ripple. Another kind of the methods sizes the capacitor by directly analyzing the capacitor voltage [29]. Since the mathematical expression of u cap (t) is complicated, the capacitor voltage fluctuation ratio ε is usually calculated by a lot of simplifications, which results in choosing an inappropriate value of capacitance.…”

Section: Capacitor Sizing For the MMC Connected To Pmsgmentioning

confidence: 99%

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A Steady-State Analysis Method for Modular Multilevel Converters Connected to Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

Liu

Sun

et al. 2018

Energies

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Modular multilevel converters (MMCs) have shown great potential in the area of multimegawatt wind energy conversion system (WECS) based on permanent magnet synchronous generators (PMSGs). However, the studies in this area are few, and most of them refer to the MMC used in high-voltage direct current (HVDC) systems, and hence the characteristics of the PMSG are not considered. This paper proposes a steady-state analysis method for MMCs connected to a PMSG-based WECS. In the proposed method, only the wind speed (operating condition) is required as input, and all the electrical quantities in the MMC, including the amplitudes, phase angles and their harmonics, can be calculated step by step. The analysis method is built on the proposed d-q frame mathematical model. Interactions of electrical quantities between the MMC and PMSG are comprehensively considered. Moreover, a new way to calculate the average switching functions are adopted in order to improve the accuracy of the analysis method. Applications of the proposed method are also presented, which includes the characteristic analysis of capacitor voltage ripples and the capacitor sizing. Finally, the accuracy of the method and the correctness of the analysis are verified by simulations and experiments.Energies 2018, 11, 461 2 of 31 require a large amount of series or parallel connected power devices in order to achieve the required power, which reduces the reliability of WECS. Moreover, the traditional converters are not suitable for medium-voltage (3-33 kV) WECS, which is becoming popular for turbine power ratings greater than 3.0 MW [6,7]. These drawbacks lead to the studies of new full-scale power converters.The modular multilevel converter (MMC), which became the most common type of voltage-source converter used in the high-voltage direct current (HVDC) applications, is also a suitable converter for PMSG-based WECS. In [8,9], MMC was used for medium-voltage motor drives, which opened up the study of MMC applied to variable-speed machines. The application of MMCs in PMSG-based WECS was first studied in [10]. That paper concluded that MMC should be considered a suitable option for transformerless 10 MW PMSG-based WECS, and performs well in the full system. In [11], the authors proposed an improved online fault identification scheme for the MMC applied to WECS, which avoided the use of extra sensors by only using the already available variables in detection, and therefore the maintenance cost of the distant offshore wind farms can be reduced. In [12], the complete control scheme of MMC applied to the PMSG-based WECS was proposed. Low voltage ride-through problems and capacitor voltage ripple problems were also studied in that paper. In addition, the increasing interest in all-dc wind farms, in recent years, will also enlarge the application of MMC in WECS [13][14][15].Steady-state analysis can be used for component sizing and assessment of the impact of different parameters on the MMC performance. However, there is no reference available for the steady-state anal...

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Selection methods of main circuit parameters for modular multilevel converters

Cited by 72 publications

References 11 publications

Optimal Design of Controller Parameters for Improving the Stability of MMC-HVDC for Wind Farm Integration

Optimal Design of Controller Parameters for Improving the Stability of MMC-HVDC for Wind Farm Integration

Bad Data Detection and Identification of Hybrid AC/DC Power Systems with Voltage Source Converters Using Deep Belief Network and K-Means Clustering

A Steady-State Analysis Method for Modular Multilevel Converters Connected to Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems

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