Operating Modes Analysis and Control Strategy of Single-Stage Isolated Modular Multilevel Converter (I-MMC) for Medium Voltage AC/DC Grid

Kong, Dehao; Liu, Chuang; Hong, Ying-Yi; Pei, Zhongchen; Li, Jinming; Zhang, Haoran

doi:10.1109/iecon.2019.8927196

Cited by 2 publications

(3 citation statements)

References 7 publications

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“…The 2L and 3L VSCs are the ones that are the most commonly used in MVDC systems at the lower voltage range, e.g., 3-6 kV [126], due to the significantly lower cost and efficiency at these voltages compared to MMCs or other multilevel converters. The 2L VSCs can be considered at voltages of up to ±28 kV DC [93], and the 3L-NPC can be considered for voltages of up to ±35 kV; however, MMCs are generally the best topology for higher voltage ranges that are above 10 kV [19,95,126,127], but at this voltage boundary, the converter should be selected on a case-by-case basis. MMCs possess benefits such as low distortion, modular design providing scalability [128], voltage balancing across switches, reduced harmonics, lower switching frequencies [127], improved fault ride through capability [108,129], and active redundancy, all of which significantly improve reliability [130,131].…”

Section: Converters 411 Ac-dc and Dc-ac Convertersmentioning

confidence: 99%

“…MVDC grids would improve systems with a high penetration of DC loads and power converters. DC loads are continuously increasing, with up to 80% of loads in commerce and residential areas being DC [19,20]; therefore, utilising MVDC systems would reduce conversion stages. Modern ship systems also often utilise DC loads and pulse-loads; loads that draw a very high current in a short time over intermittent periods [21].…”

Section: Introductionmentioning

confidence: 99%

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Review of MVDC Applications, Technologies, and Future Prospects

Coffey

Timmers

et al. 2021

Energies

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This paper presents a complete review of MVDC applications and their required technologies. Four main MVDC applications were investigated: rail, shipboard systems, distribution grids, and offshore collection systems. For each application, the voltage and power levels, grid structures, converter topologies, and protection and control structure were reviewed. Case studies of the varying applications as well as the literature were analyzed to ascertain the common trends and to review suggested future topologies. For rail, ship, and distribution systems, the technology and ability to implement MVDC grids is available, and there are already a number of case studies. Offshore wind collection systems, however, are yet able to be implemented. Across the four applications, the MVDC voltages ranged from 5–50 kV DC and tens of MW, with some papers suggesting an upper limit of 100 kV DC and hundreds of MV for distribution networks and offshore wind farm applications. This enables the use of varying technologies at both the lower and high voltage ranges, giving flexibility in the choice of topology that is required required.

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Section: Converters 411 Ac-dc and Dc-ac Convertersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Review of MVDC Applications, Technologies, and Future Prospects

Coffey

Timmers

et al. 2021

Energies

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“…The PET can operate well even if some sub modules fail, and then the reliability of the PET can be improved. Also the dc discrete voltages can stay when the MVDC distribution grid fails as the SCs could not discharge, and then the PET can put into operation quickly when the fault is eliminated [14]- [15]. All modules are connected in parallel on the LV side.…”

Section: Proposed Pet Based On Switched Capacitormentioning

confidence: 99%

DAB Based DC-DC High Frequency Link PET for Interconnecting MVDC-LVDC Grids

Deshpande¹

2021

IJMTST

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This paper proposes dual active bridge (DAB) based high frequency power electronic transformer (PET) for interconnecting medium voltage dc (MVDC) and low voltage dc (LVDC) grids for dc power distribution. The above proposed concept works on dual active phase shift principle and square wave HF modulation technique for bidirectional power transfer. Compared to the traditional dc transformer scheme, The proposed power electronic transformer (PET) can disconnect from LVDC distribution grid effectively as a dc breaker when a short circuit fault occurs in the distribution grid. The isolated DC-DC PET topology with a wide range of voltage conversion ratio is useful for High Voltage DC tapping. The DAB based on switched capacitor is connected to the medium voltage DC side and acts as an inverter. The proposed topology has the ability to transfer higher power, and lower circulating power, lower high frequency link voltage, and RMS current and peak values with the same transmission power in the MVDC side. This paper analyzes the topology, voltage and power characterization, control strategy in detail. Increase in the intermediate AC frequency will reduce the size of the transformer and other passive elements significantly in the circuit. The theoretical analysis is supported by MATLAB simulation.

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Operating Modes Analysis and Control Strategy of Single-Stage Isolated Modular Multilevel Converter (I-MMC) for Medium Voltage AC/DC Grid

Cited by 2 publications

References 7 publications

Review of MVDC Applications, Technologies, and Future Prospects

Review of MVDC Applications, Technologies, and Future Prospects

DAB Based DC-DC High Frequency Link PET for Interconnecting MVDC-LVDC Grids

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