The Alternate Arm Converter “Extended-Overlap” Mode: AC Faults

Farr, Ewan; Feldman, Ralph; Clare, John; Jasim, Omar

doi:10.1109/tpel.2020.3026568

Cited by 10 publications

(5 citation statements)

References 34 publications

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“…However, under the traditional PW-CVB method, since t1~t3 (see (9)) differs with M, the upper and lower DSs have different power losses except when M=π/4. It can result in inconsistent heat generation and lifespan of power switches, potentially affecting the reliability of the system.…”

Section: (Pw-cvb)mentioning

confidence: 99%

“…To address the aforementioned drawbacks of MMC, Davidson et al introduced a variety of hybrid converters [7], including the alternative arm converter (AAC) and hybrid multilevel converter (HMC). The AAC and HMC both utilize a combination of two-level directional switches (DSs) and cascaded full-bridge submodules (FBSMs) to provide a smaller SM number, lower capacitor energy fluctuations, and the ability to block DC faults [8], [9]. Compared to the AAC, the HMC has a much higher SM utilization, as well as a smaller volume and cost.…”

Section: Introductionmentioning

confidence: 99%

“…To improve the CVB capability, the extended-overlap control with a duration of 60° can be implemented [18], [19], [20]. However, the operation mode of the AAC with extended-overlap control is similar to that of a conventional MMC, leading to extra SMs, abundant DSs, and increased loss [9]. Unfortunately, the overlap control cannot be applied to the HMC due to the placement of the cascaded FBSMs on the AC side.…”

Section: Introductionmentioning

confidence: 99%

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Capacitor Voltage Balancing Method for the Hybrid Multilevel Converter Considering Grid Voltage Sags

Zhang,

Wang,

et al. 2024

IEEE Trans. Power Electron.

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Compared to the traditional modular multilevel converter (MMC) and alternative arm converter (AAC), the hybrid multilevel converter (HMC) exhibits superiority in terms of cost and volume. In the HMC, the pulse width of the direction switch (DS) is conventionally utilized to maintain capacitor voltage balancing (CVB). However, this method has certain limitations, including a restricted range of modulation indices and the inability to support pure reactive power operation. To address these drawbacks, a new CVB method based on the phase angle of the DS is proposed in this paper. Compared to the traditional method, the proposed method enables the HMC to achieve a full range of modulation index and four-quadrant operation. Additionally, it demonstrates improved performance in terms of SM capacitance and capacitor voltage ripple, especially under severe grid voltage sags and low power factors. A comparative analysis is conducted between two CVB methods, focusing on the SM number, switch number, and SM capacitance. Furthermore, a unified control strategy considering asymmetrical and symmetrical grid voltage sags is proposed for these two CVB methods. Finally, the effectiveness and superiority of the proposed CVB methods are verified by simulation and experimental testing.

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Section: (Pw-cvb)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Capacitor Voltage Balancing Method for the Hybrid Multilevel Converter Considering Grid Voltage Sags

Zhang,

Wang,

et al. 2024

IEEE Trans. Power Electron.

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“…Yet, FB-MMCs have not gained prominence within the industry because of the large number of switching devices required, high losses, and bulky capacitors. A few FB-MMC alternatives are proposed recently in literature [28], [29], [30], [31], [32], [33]. MMC with a mix of half-bridge submodule (HB-SM) and full-bride submodule (FB-SM) in each arm combine the lower loss advantage of HB-SM with fault-blocking capabilities of FB-SMs.…”

Section: Introductionmentioning

confidence: 99%

Modeling and Control of a Hybrid Modular Multilevel Converter for High-AC/Low-DC Medium-Voltage Applications

Motwani,

Liu,

Boroyevich

et al. 2024

IEEE Trans. Power Electron.

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“…Yet, FB-MMCs have not gained prominence within the industry because of the large number of switching devices required, high losses, and bulky capacitors. A few FB-MMC alternatives are proposed recently in literature [28]- [33]. MMC with a mix of half-bridge submodule (HB-SM) and full-bride submodule (FB-SM) in each arm combine the lower loss advantage of HB-SM with fault-blocking capabilities of FB-SMs.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Modular Multilevel Converters for High-AC/Low-DC Medium-Voltage Applications

Motwani

Liu

Burgos

et al. 2023

IEEE Open J. Power Electron.

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With ever-increasing power-density requirements, technologies such as energy storage systems and electric-vehicles can benefit greatly from interfacing medium-voltage (MV)-AC grid like 13.8kV or 30kV using high-AC/low-DC voltage converter. Using modular high-AC/low-DC voltage converter can help increase power-density and efficiency, while reducing total conversion steps and providing flexibility. Full-bridge modular multilevel converters (FB-MMC) and solid-state transformers are existing solutions for such operations, but suffer from limitations of high semiconductor requirements, large submodule capacitors and/or many high-frequency transformers. Three new hybrid-MMC (HMMC) topologies are proposed in this paper as alternative solutions for such high-AC/low-DC voltage operations. Each of the three developed HMMCs utilizes a unique combination of low-frequency high-voltage switches and fast-switching low-voltage switch based submodules to generate multilevel-AC voltage. HMMCs are compared extensively to state-of-the-art FB-MMC and are shown to have semiconductor savings of over 27%, 38% lower submodule capacitor size, and 53% lower losses for 13.8-kV-AC/6-kV-DC operation. Due to these benefits like higher efficiency, significantly smaller submodule capacitance requirements, and fewer semiconductors, HMMCs can be an excellent option for high-AC/low-DC applications. Practical considerations like snubber and DC split-capacitor requirement are also elaborated for developing and commercializing HMMCs. Comparison results are verified using a 17.5 kW three-phase MV laboratory prototype.

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The Alternate Arm Converter “Extended-Overlap” Mode: AC Faults

Cited by 10 publications

References 34 publications

Capacitor Voltage Balancing Method for the Hybrid Multilevel Converter Considering Grid Voltage Sags

Capacitor Voltage Balancing Method for the Hybrid Multilevel Converter Considering Grid Voltage Sags

Modeling and Control of a Hybrid Modular Multilevel Converter for High-AC/Low-DC Medium-Voltage Applications

Hybrid Modular Multilevel Converters for High-AC/Low-DC Medium-Voltage Applications

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