Energy equalization module for modular multilevel converters in variable speed motor drives

Sleiman, Mohammad; Koteich, Mohamad; Blanchette, Handy Fortin; Kanaan, Hadi Y.; Al‐Haddad, Kamal

doi:10.1109/redec.2016.7577559

Cited by 20 publications

(13 citation statements)

References 11 publications

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“…By substituting Equations 7and (8) into Equations (10) and (11), the change in the capacitor voltage in upper and lower arms are expressed by Equations (12) and (13) respectively.…”

Section: Hbmmc Capacitor Voltage Ripple Calculationmentioning

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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“…By substituting Equations 7and (8) into Equations (10) and (11), the change in the capacitor voltage in upper and lower arms are expressed by Equations (12) and (13) respectively.…”

Section: Hbmmc Capacitor Voltage Ripple Calculationmentioning

confidence: 99%

Arm current reversal‐based modular multilevel DC‐DC converter

Nazih

Hossam-Eldin

Elserougi

2021

IET Power Electronics

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“…A voltage balancing algorithm is needed to select proper FBSMs to be activated to ensure operating with balanced capacitor voltages, i.e., capacitor voltages and arm currents measurements are mandatory. It is worth to mention that based on Fig.3, the absolute value of arm voltage reference is interchanged between arms of the same leg due to swapping Fig.3a which are given by (13) and (14) respectively; (14) and the corresponding arm currents are given by (15);…”

Section: A Zero-/low-frequency Operational Modementioning

confidence: 99%

“…This arrangement is controlled to drive a three-phase motor from zero speed to full-load speed with balanced and bounded capacitor voltages, but a large number of FBSMs are employed. In [13], the energy equalization modules concept has been presented to ensure the energy balance between the upper and lower arms of MMC during the low-frequency condition. Dual active bridge equalization channels concept has been proposed in [14]- [16] for different types of machine drives, while the shared capacitor SM concept has been proposed in [17] for open-winding machine drives.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Modular Multilevel Converter With Arm-Interchange Concept for Zero-/Low- Frequency Operation of AC Drives

et al. 2020

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DC-AC Modular Multilevel Converter (MMC) is a promising candidate for high-power AC drive applications. The main challenge of operating the MMC in AC drive applications is its performance during low-frequency conditions, as high voltage ripple is associated with the low-frequency operation, which results in voltage stresses on the involved semiconductor devices. To keep capacitor voltages balanced and bounded in low-frequency operation, different techniques have been proposed in literature, which can be classified into software and hardware approaches. In this paper, a hybrid MMC with arm-interchange concept is proposed to ensure operating successfully during low-frequency conditions. The hybrid MMC consists of two-stages. The first stage is a front-end Integrated Gate Commutated Thyristor (IGCT)-based H-bridge converter, while the second stage is a Full-Bridge Sub-Module (FBSM)-based MMC, where FBSMs is able to generate positive, zero, and negative voltage states. Detailed illustration and design of the hybrid MMC are introduced. Simulation results of the proposed converter are presented to show the effectiveness during low-frequency and normal frequency conditions in AC drive applications. Finally, a scaled-down prototype is employed for experimental validation.

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“…Instead of proposing special DC–DC converter topologies, some researches suggested using conventional MMC in DC–DC conversion but with the help of extra hardware circuits, namely, energy equalising modules (EEMs) [14–18]. The EEMs are connected between the upper and lower arms in the same leg to provide a channel to transfer the energy from the higher energy arm to the lower energy arm to ensure arms energy balance condition.…”

Section: Introductionmentioning

confidence: 99%

“…The EEMs are connected between the upper and lower arms in the same leg to provide a channel to transfer the energy from the higher energy arm to the lower energy arm to ensure arms energy balance condition. Different types of EEM have been proposed in literature, such as dual half‐bridge based EEM [14–17] and DC–DC flyback converter‐based EEMs [18]. Employing EEMs requires many semiconductor devices, isolating transformers, and EEMs controllers, which complicate the architecture and affect negatively the overall cost of the converter.…”

Section: Introductionmentioning

confidence: 99%