Modular Smart Transformer architectures: An overview and proposal of a interphase architecture

Costa, Levy Ferreira; Buticchi, Giampaolo; Liserre, Marco

doi:10.1109/pedg.2017.7972557

Cited by 16 publications

(5 citation statements)

References 15 publications

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“…The smart transformer (ST) is an intelligent distribution substation based on the power electronics which can be implemented on the basis of a solid state transformer (SST) or on the basis of a back-to-back converter plus a standard transformer. In the framework of smart grids, the ST concept has recently attracted the attention of industry for the capability to regulate the voltage, the frequency, the active and reactive power flow, and to allow meshed-operations of distributed feeders [1][2][3][4][5][6]. Considering the modular three-stage ST based on the cascaded H-bridge (CHB) converter and the dual active bridge (DAB) converters in Fig.…”

Section: Introductionmentioning

confidence: 99%

Soft-Start Procedure for a Three-Stage Smart Transformer Based on Dual-Active Bridge and Cascaded H-Bridge Converters

Pugliese

Buticchi

Mastromauro

et al. 2020

IEEE Trans. Power Electron.

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Power electronics-based three-stage smart transformers (ST) can be seriously damaged by inrush currents and overvoltages during the start-up phase if the control of the stages is not correctly coordinated. Hence, it is crucial to design properly the start-up procedure, especially in case of modular architectures with distributed DC-links. The design of the start-up procedure depends on the ST power stages topologies, their control systems and the operation modes. This work proposes a soft-shift start modulation technique that allows to limit the inrush current in the DC/DC isolation stage during the DC-link capacitors pre-charging. A fast voltage balancing control, performed by the DC/DC isolation stage, is introduced to avoid overvoltages and unbalanced voltage conditions among the different power cells. Under the proposed method, fast control dynamics is guaranteed thanks to the high frequency bandwidth of the DC/DC isolation stage converters. Theoretical analysis, based on a detailed small signal model of the ST, and simulations are used to demonstrate the principle of the operation. Experimental results, carried out in a ST prototype, confirm the performances of proposed solution in realizing a smooth start-up without voltage/current overshoots.

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Section: Introductionmentioning

confidence: 99%

Soft-Start Procedure for a Three-Stage Smart Transformer Based on Dual-Active Bridge and Cascaded H-Bridge Converters

Pugliese

Buticchi

Mastromauro

et al. 2020

IEEE Trans. Power Electron.

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“…For the entire discussion, the combination of MMC HBSM and DC/DC converters is called submodule. There are two alternatives to connect the submodules [27]. The submodules can be connected in a horizontal way, where they are connected to each phase of the MMC arm, as shown in Fig.…”

Section: Four-port Mmc-based Sstmentioning

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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“…Figure 8. MFT configurations used in SST: (a) single phase transformer [4], (b) three phase transformer [49], (c) single phase multi-winding transformer [55], (d) three phase multi-winding transformer [56], (e) split winding transformer [57], and (f) scott transformer [16]. [32]: (a) SST i-cell formed using single phase transformer and single SST cell , (b) SST i-cell formed using single phase transformer and multiple SST cell , (c) SST i-cell for multi-winding transformer, (d) SST i-cell using three phase transformer and three phase SST cell , and (e) SST i-cell formed using a three phase transformer and multiple single phase SST cell .…”

Section: Converter Integration Level: Siso Configuration-imentioning

confidence: 99%

“…Unlike DAB, the performance of SRC depends of the accuracy of the resonance frequency of the circuit, which might change as passive components age or load changes worsening its performance. Thus, DAB has emerged as a preferred choice over SRC especially for SSTs in distributed systems [55]. Therefore, the selection of isolation stage based on resonance or non-resonance circuit depends on the application.…”

Section: Isolation Stage Based On Resonance Circuitsmentioning

confidence: 99%

See 1 more Smart Citation

Solid State Transformers: Concepts, Classification, and Control

et al. 2020

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Increase in global energy demand and constraints from fossil fuels have encouraged a growing share of renewable energy resources in the utility grid. Accordingly, an increased penetration of direct current (DC) power sources and loads (e.g., solar photovoltaics and electric vehicles) as well as the necessity for active power flow control has been witnessed in the power distribution networks. Passive transformers are susceptible to DC offset and possess no controllability when employed in smart grids. Solid state transformers (SSTs) are identified as a potential solution to modernize and harmonize alternating current (AC) and DC electrical networks and as suitable solutions in applications such as traction, electric ships, and aerospace industry. This paper provides a complete overview on SST: concepts, topologies, classification, power converters, material selection, and key aspects for design criteria and control schemes proposed in the literature. It also proposes a simple terminology to identify and homogenize the large number of definitions and structures currently reported in the literature.

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Modular Smart Transformer architectures: An overview and proposal of a interphase architecture

Cited by 16 publications

References 15 publications

Soft-Start Procedure for a Three-Stage Smart Transformer Based on Dual-Active Bridge and Cascaded H-Bridge Converters

Soft-Start Procedure for a Three-Stage Smart Transformer Based on Dual-Active Bridge and Cascaded H-Bridge Converters

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

Solid State Transformers: Concepts, Classification, and Control

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