A new three-level switched-capacitor submodule for modular multilevel converters

Elserougi, Ahmed A.; Ahmed, Shehab; Massoud, Ahmed M.

doi:10.1109/icit.2016.7474757

Cited by 6 publications

(4 citation statements)

References 13 publications

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“…Such structures may provide a fault current blocking state to the converter; however, the interruption of the fault current in the main path and the lack of fault current dissipation paths can lead to substantial over-voltages and potential destruction of the SMs during a dc-fault. Other unipolar structures include the stacked switched capacitor SM [35,36] and the three-level switch capacitor SM [37], shown in Figure 4f,g respectively. The switched capacitor structure allows for one or more capacitors to be inserted in series to the main SM capacitor, effectively reducing the required capacitance (and energy stored in the MMC arms) for the same voltage ripple but at the cost of additional devices.…”

Section: Unipolar Smsmentioning

confidence: 99%

Review, Classification and Loss Comparison of Modular Multilevel Converter Submodules for HVDC Applications

Tian

Wickramasinghe

et al. 2022

Energies

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The circuit topology of a submodule (SM) in an modular multilevel converter (MMC) defines many of the functionalities of the complete power electronics conversion system and the specific applications that a specific MMC configuration can support. Most prominent among all applications for the MMC is its use in high-voltage direct current (HVDC) transmission systems and multiterminal dc grids. The aim of the paper is to provide a comprehensive review and classification of the many different SM circuit topologies that have been proposed for the MMC up to date. Using an 800-MVA, point-to-point MMC-based HVDC transmission system as a benchmark, the presented analysis identifies the limitations and drawbacks of certain SM configurations that limit their broader adoption as MMC SMs. A hybrid model of an MMC arm and appropriate implementations of voltage-balancing algorithms are used for detailed loss comparison of all SMs and to quantify differences among multiple SMs. The review also provides a comprehensive benchmark among all SM configurations, broad recommendations for the benefits and limitations of different SM topologies which can be further expanded based on the requirements of a specific application, and identifies future opportunities.

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Section: Unipolar Smsmentioning

confidence: 99%

Review, Classification and Loss Comparison of Modular Multilevel Converter Submodules for HVDC Applications

Tian

Wickramasinghe

et al. 2022

Energies

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“…The topology features parallel connection of switches and capacitors, reducing conduction losses R6 and improving capacitor voltage balancing and harmonic performance R1 . In a similar way, the switched-capacitor (SC) SM presented in [141] and shown in Fig. 6(e), also features the parallel connection of capacitors and switches.…”

Section: ) Unipolar Voltage Smsmentioning

confidence: 99%

Comparative Evaluation of Voltage Source Converters With Silicon Carbide Semiconductor Devices for High-Voltage Direct Current Transmission

Jacobs

Heinig

Johannesson

et al. 2021

IEEE Trans. Power Electron.

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Recent advancements in silicon carbide (SiC) power semiconductor technology enable developments in the high-power sector, e.g., high-voltage direct current (HVdc) converters for transmission, where today silicon (Si) devices are state-of-theart. New submodule (SM) topologies for modular multilevel converters (MMCs) offer benefits in combination with these new SiC semiconductors. This paper reviews developments in both fields, SiC power semiconductor devices and SM topologies, and evaluates their combined performance in relation to core requirements for HVdc converters: grid code compliance, reliability, and cost.A detailed comparison of SM topologies regarding their structural properties, design and control complexity, voltage capability, losses, and fault handling is given. Alternatives to state-of-the-art SMs with Si insulated-gate bipolar transistors (IGBTs) are proposed, and several promising design approaches are discussed. Most advantages can be gained from three technology features. Firstly, SM bipolar capability enables dc fault handling and reduced energy storage requirements. Secondly, SM topologies with parallel conduction paths in combination with SiC metal-oxide-semiconductor field effect transistors (MOSFETs) offer reduced losses. Thirdly, a higher SM voltage enabled by higher blocking voltage of SiC devices results in reduced converter complexity. For the latter, ultra-high-voltage (UHV) bipolar devices, such as SiC IGBTs and SiC gate turn-off thyristors (GTOs), are envisioned. Index Terms-HVdc transmission, modular multilevel converter, power semiconductor devices, silicon carbide, submodules. I. INTRODUCTIONH VDC transmission technology requires integration into the existing alternating current (ac) grid. The conversion is performed via high-power converters. The modular multilevel converter (MMC) is a versatile and flexible topology with several options for optimization. MMCs have been intensively investigated since the early 2000's. It was identified, that modularity, scalability, built-in redundancy, and harmonic performance are advantageous for meeting widely varying requirements in grid applications. Compared to previous voltage source converters (VSC), the need for bulky harmonic filters is Keijo Jacobs

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“…The proposed configuration is a two-stage modular DC-DC converter, which comprises a half-bridge single-phase MMC with half-bridge SMs (HBSMs) followed by an H-bridge singlephase MMC with HBSMs connected to its output as illustrated in Figure 2. In the first stage, the output voltage of the HBMMC FIGURE 4 The operational concept of the proposed MMC is controlled, such that it generates the desired output voltage (V o ) only in half of a predetermined periodic swapping time (T b ), which can be named, the positive half cycle. While the HBMMC generates the negative value of the desired output voltage (−V o ) in the other half, which can be named, the negative half cycle.…”

Section: The Proposed Configurationmentioning

confidence: 99%

“…The modular multilevel converter (MMC) has shown promising potential in HV high-power applications due to its astonishing benefits, which include redundancy, modularity, and scalability [1][2][3][4]. Each leg in the conventional MMC comprises two arms, where each arm consists of series-connected submodules (SMs).…”

Section: Introductionmentioning

confidence: 99%

Arm current reversal‐based modular multilevel DC‐DC converter

Nazih

Hossam-Eldin

Elserougi

2021

IET Power Electronics

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Nowadays, most of the converters used in high-power high-voltage (HV) applications are the conventional modular multilevel converters (MMC). However, in the case of DC-DC conversion, an imbalance of the capacitor voltages occurs and the conventional MMC fails to operate correctly. This paper introduces an arm current reversal-based modular multilevel DC-DC converter, which successfully provides balance among the capacitor voltages while operating in DC-DC conversion. The proposed configuration is used in medium voltage DC grids to feed DC loads or to interconnect between two DC grids of different voltage levels. The proposed converter is a two-stage DC-DC modular converter, which consists of a single-phase half-bridge MMC with half-bridge submodules (HBMMC) followed by a single-phase H-bridge MMC with half-bridge submodules (SMs). The operational concept of the proposed converter is based on reversing the arm current direction and reversing the output terminals with the help of the H-bridge MMC stage, which ensures the same direction of the voltage at the load terminals. The proposed converter provides a high conversion ratio, bidirectional power flow, simple architecture, and a simple control scheme. Detailed illustrations, analysis, and design of the proposed converter are presented. Besides, MATLAB-based and Opal RT-based simulation results and experimental results are presented to validate the proposed configuration claims. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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A new three-level switched-capacitor submodule for modular multilevel converters

Cited by 6 publications

References 13 publications

Review, Classification and Loss Comparison of Modular Multilevel Converter Submodules for HVDC Applications

Review, Classification and Loss Comparison of Modular Multilevel Converter Submodules for HVDC Applications

Comparative Evaluation of Voltage Source Converters With Silicon Carbide Semiconductor Devices for High-Voltage Direct Current Transmission

Arm current reversal‐based modular multilevel DC‐DC converter

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