An Inductive-Filtering Strategy of Submodule Ripple-Power in Triple-Port MMC-Based SST Applied to Hybrid Medium and Low Voltage AC/DC Interface

Teng, Jiaxun; Sun, Xiaofeng; Pan, Yuzhuo; Liu, Xuemin; Zhang, Yongrui; Zhao, Wei; Li, Xin

doi:10.1109/tpel.2022.3144279

Cited by 20 publications

(4 citation statements)

References 56 publications

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“…The structure in Fig. 2(c) has the full modularity aspect and a common DC-link for the system [6], [7], [8], [9]. This structure consists of a modular multilevel converter (MMC) as the AC/DC conversion between the MVAC and MVDC as well as DC/DC converters connected to each MMC submodule capacitor to construct the LVDC port.…”

Section: Introductionmentioning

confidence: 99%

Submodule Capacitor Voltage Balancing Through High-Frequency-Side Control for Multiport MMC-Based Solid-State Transformers

Budiwicaksana,

Lee

2024

IEEE Open J. Ind. Electron. Soc.

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This paper proposes a novel submodule capacitor voltage balancing control for multiport modular multilevel converter (MMC)-based solid-state transformers (SSTs). To balance each submodule capacitor voltage, the balancing control is usually applied to the MMC. However, the low switching frequency operation and bulky arm inductance of the MMC limit the controller bandwidth and stability margin. These issues are addressed by moving the balancing control to the back-end DC/DC converter which is operated at high switching frequency. The controller gains are designed based on the small-signal model. The superiority of the proposed controller over the conventional one has been verified through Bode plot, pole-zero map, and Nyquist path analyses. Experimental results for a 2.4 kW prototype system have also verified the accuracy of the model and effectiveness of the proposed balancing control for step load changes.INDEX TERMS Balancing control, modeling, modular multilevel converters, solid-state transformer. FIGURE 1. Basic structure and application of a multiport SST.

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Section: Introductionmentioning

confidence: 99%

Submodule Capacitor Voltage Balancing Through High-Frequency-Side Control for Multiport MMC-Based Solid-State Transformers

Budiwicaksana,

Lee

2024

IEEE Open J. Ind. Electron. Soc.

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“…ith the rapid development of new energy power generation, such as wind power and photovoltaic power, long-distance high-voltage direct current (HVDC) transmission for new energy has emerged [1]- [3]. The AC-DC converter plays a crucial role in voltage conversion, and reducing its size and cost has become a significant research topic of concern to scholars worldwide [4].…”

Section: Introductionmentioning

confidence: 99%

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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“…In addition, in [18][19][20] and in [10,[21][22][23][24][25][26][27], the MMC converts a single-phase and a three-phase MV grid, respectively, into a square wave mediumfrequency voltage. Furthermore, in [28][29][30][31], the MMC submodules directly connect to multiple medium-frequency transformers and ac/dc converters, and the MMC legs connect to a dc bus voltage. However, the MMC with a single-phase ac and a dc bus voltage port, as in [26][27][28][29][30][31], is not needed in this application.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, in [28][29][30][31], the MMC submodules directly connect to multiple medium-frequency transformers and ac/dc converters, and the MMC legs connect to a dc bus voltage. However, the MMC with a single-phase ac and a dc bus voltage port, as in [26][27][28][29][30][31], is not needed in this application. Therefore, the proposed ultrafast charger in Figure 1b implements a three-phase to single-phase ac/ac MMC with FB SMs.…”

Section: Introductionmentioning

confidence: 99%

Single-Stage MV-Connected Charger Using an Ac/Ac Modular Multilevel Converter

Marca,

Roes,

Wijnands

et al. 2024

Energies

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Modular multilevel converters with non-sinusoidal ac voltage output can reduce cost and volume in medium-voltage-connected electric vehicle battery charging applications. The use of full-bridge submodules in such converters enables single-stage ac/ac voltage conversion, allowing a medium-voltage grid to be directly connected to a medium-frequency isolation transformer. The application of a square wave voltage at the medium-frequency transformer’s single-phase port enhances the converter’s efficiency and power density in comparison to a sinusoidal voltage. This paper presents the analysis and modelling of a modular multilevel converter, comparing its operation with sinusoidal and square wave output voltages. A single control scheme for both output voltage waveforms is proposed for the three-phase and single-phase ac currents, circulating currents, and the energy stored in the submodule capacitors. The control strategy of the three-phase and single-phase port currents is verified through simulation and experiments using a scaled-down prototype, thereby validating its suitability for high-power bidirectional battery chargers.

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An Inductive-Filtering Strategy of Submodule Ripple-Power in Triple-Port MMC-Based SST Applied to Hybrid Medium and Low Voltage AC/DC Interface

Cited by 20 publications

References 56 publications

Submodule Capacitor Voltage Balancing Through High-Frequency-Side Control for Multiport MMC-Based Solid-State Transformers

Submodule Capacitor Voltage Balancing Through High-Frequency-Side Control for Multiport MMC-Based Solid-State Transformers

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

Single-Stage MV-Connected Charger Using an Ac/Ac Modular Multilevel Converter

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