Capacitor Voltage Reduction in Modular Multilevel Converters Under Grid Voltages Unbalances

Li, Jie; Konstantinou, Georgios; Wickramasinghe, Harith R.; Townsend, Christopher D.; Pou, Josep

doi:10.1109/tpwrd.2019.2919788

Cited by 20 publications

(20 citation statements)

References 37 publications

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“…Here we elaborate how this proposed method can be easily extended to other unbalanced grid conditions: There are 4 types of unbalanced grid conditions [19], [20]: Two-phase-to-ground fault, three-phase-to-ground fault, single-phase-to-ground fault, and phase-to-phase short circuit fault. In this paper, the vector definition of grid under two-phase-to-ground fault is expressed as equation (3). The vector definitions of other unbalanced grid conditions are shown in Table II (see below).…”

Section: Extension Of the Proposed Methods To Other Unbalanced Gridmentioning

confidence: 99%

“…As a result, the capacitor voltage ripples will be unbalanced and will present higher amplitudes [2]. High SM capacitor voltages will cause tripping of the MMC system immediately if they exceed the safe voltage limit [3]. Therefore, the safe operating region of the MMC is limited during such faults [4].…”

Section: Introductionmentioning

confidence: 99%

“…In other words, the theoretical foundation set in [15] is not sufficient to explicitly derive circulating current references for controlling three-phase SM submodule capacitor voltage ripples. In [3], an offset pulse-width modulation (OPWM) and zero sequence voltage injection method is proposed. The three-phase offsets added to the duty ratios to reduce the average SM capacitor voltages of the arms during unbalanced grid conditions [3].…”

Section: Introductionmentioning

confidence: 99%

“…In [3], an offset pulse-width modulation (OPWM) and zero sequence voltage injection method is proposed. The three-phase offsets added to the duty ratios to reduce the average SM capacitor voltages of the arms during unbalanced grid conditions [3]. However, this paper still does not address the accurate relation between submodule capacitor voltage ripples and circulating current references.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Machine Learning Based Operating Region Extension of Modular Multilevel Converters Under Unbalanced Grid Faults

Wang

Dragičević

Gao

et al. 2021

IEEE Trans. Ind. Electron.

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The capacitor voltage ripples of the modular multilevel converter (MMC) are increased under unbalanced grid fault conditions. Since high capacitor voltage ripples deteriorate their lifetimes and may even cause tripping of the MMC system, it is important to restrict them. To this end, it is well known that injecting double fundamental frequency circulating currents can reduce the capacitor voltage ripples. However, finding a proper circulating current reference to achieve desired ripples analytically is complicated. This paper proposes an alternative method to quickly calculate the proper circulating current references without analytical computations, which is achieved by an artificial neural network (ANN) trained to approximate the relationship between circulating current references and capacitor voltage ripples. The training data is firstly extracted from a detailed simulation model of the MMC. Afterwards, the ANN is trained by the input-output data to obtain the mapping relationship, which is then used to derive the desired circulating current references. Both the simulation and the experimental results verify the practicability of the proposed method, where the operating region can be extended 30% at a minimum in all testing conditions.

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Section: Extension Of the Proposed Methods To Other Unbalanced Gridmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Machine Learning Based Operating Region Extension of Modular Multilevel Converters Under Unbalanced Grid Faults

Wang

Dragičević

Gao

et al. 2021

IEEE Trans. Ind. Electron.

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“…There are different types of submodule used in MMC such as half-bridge submodule, full-bridge submodule, flying capacitance, neutral point clamp, etc. The half-bridge submodule is efficient as compared to other submodules [Jaiswal, R. et al, 2019;Li, J. et al, 2020].…”

Section: Mathematical Analysis Of Modular Multilevel Converter (Mmc) Fed Bldc Motormentioning

confidence: 99%

Design and Development of Experimental Based Phase Modulated Model Predictive Control for Torque Ripple Reduction of MMC Fed BLDC Motor

Jaiswal

Agarwal²,

Negi³

et al. 2021

JER is an international, peer-reviewed journal that publishes f

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This article represents the torque ripple performance of modular multilevel converter (MMC) fed brushless dc (BLDC) motor using different current control technique. For reducing the ripple current in BLDC motor, a phase-modulated model predictive control (PMMPC) technique has been proposed. The stator ripple current is almost negligible using PMMPC. This PMMPC current control method is a significant minimization of torque ripple in BLDC motor. A comparative torque ripple behaviour of MMC fed BLDC motor has been done using phase-modulated model predictive control, model predictive control (MPC) and proportional integral (PI) control at different switching frequency. It has been observed that a PMMPC current control technique is more efficient as compared to the MPC as well as PI current control technique. It has also been observed that the torque ripple performance is improved while using PMMPC as compared to the MPC and PI controller. Simulation results have been verified with the help of experimental result and these results are obtained in good agreement to the simulated results.

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Control of MMCs Under AC Grid Faults

2023

Modular Multilevel Converters

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Capacitor Voltage Reduction in Modular Multilevel Converters Under Grid Voltages Unbalances

Cited by 20 publications

References 37 publications

Machine Learning Based Operating Region Extension of Modular Multilevel Converters Under Unbalanced Grid Faults

Machine Learning Based Operating Region Extension of Modular Multilevel Converters Under Unbalanced Grid Faults

Design and Development of Experimental Based Phase Modulated Model Predictive Control for Torque Ripple Reduction of MMC Fed BLDC Motor

Control of MMCs Under AC Grid Faults

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