DC Solid State Transformer Based on Three-Level Power Module for Interconnecting MV and LV DC Distribution Systems

Zhao, Xiaodong; Li, Binbin; Fu, Qintian; Mao, Shukai; Xu, Dianguo; Leon, Jose I.; Franquelo, Leopoldo G.

doi:10.1109/tpel.2020.3007674

Cited by 39 publications

(13 citation statements)

References 33 publications

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“…In Ref. [15], experts conduct the LVRT fulfillment for the mediumvoltage DC side of a PET through the integration of an active front end into the double active bridge (DAB). In Ref.…”

Section: Literature Reviewmentioning

confidence: 99%

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Chen

Qiao

Zhao

et al. 2022

Energy Science & Engineering

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Power electronic transformer (PET) should have a satisfying low-voltage ridethrough (LVRT) ability to cope with different kinds and severities of voltage sags. To solve the LVRT issue, this paper proposes to coordinate mode switching control (MSC) and superconducting magnetic energy storage (SMES), and it is to realize the targets of promoting voltage recovery, keeping DC-link stabilization, and alleviating current inrush. First, the theoretical modeling of a PET incorporating with a SMES unit is implemented, and the PET's fault transient characterizes as well as the SMES's potential supportability is analyzed. Then, the coordination philosophy of the MSC and the SMES is presented. For that the voltage sag reaches a certain threshold, the MSC is enabled to remove the PET's normal control, and the SMES collaboratively operates to lower the DC-link overvoltage, while avoiding the PET damage. In the process of the coordination control handling the voltage transients, a proper reactive current injection is carried out at the PET's output stage to assist the voltage recovery, and the PET can possess a better LVRT margin. Using MATLAB, a 3 MW PET with an 8 H/1.2 MJ SMES unit is modeled, and different voltage sag scenarios and utilization ways of the MSC and the SMES are simulated. The comparative analysis results show that the proposed approach realizes a satisfying LVRT for the PET.

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“…In Ref. [15], experts conduct the LVRT fulfillment for the mediumvoltage DC side of a PET through the integration of an active front end into the double active bridge (DAB). In Ref.…”

Section: Literature Reviewmentioning

confidence: 99%

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Chen

Qiao

Zhao

et al. 2022

Energy Science & Engineering

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“…MV AC at the primary side and two LV DC at the secondary side, formed from the two outputs of the transformer [119] Multi-stage with multilevel DC-DC, and isolation based on a DC-DC formed by an NPC (primary side) and by a full-bridge (secondary side)…”

Section: Referencesmentioning

confidence: 99%

Review of a Disruptive Vision of Future Power Grids: A New Path Based on Hybrid AC/DC Grids and Solid-State Transformers

et al. 2021

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Power grids are evolving with the aim to guarantee sustainability and higher levels of power quality for universal access to electricity. More specifically, over the last two decades, power grids have been targeted for significant changes, including migration from centralized to decentralized paradigms as a corollary of intensive integration of novel electrical technologies and the availability of derived equipment. This paper addresses a review of a disruptive vision of future power grids, mainly focusing on the use of hybrid AC/DC grids and solid‑state transformers technologies. Regarding hybrid AC/DC grids in particular, they are analyzed in detail in the context of unipolar and bipolar DC grids (i.e., two‑wire or three‑wire DC grids), as well as the different structures concerning coupled and decoupled AC configurations with low‑frequency or high‑frequency isolation. The contextualization of the possible configurations of solid‑state transformers and the different configurations of hybrid transformers (in the perspective of offering benefits for increasing power quality in terms of currents or voltages) is also analyzed within the perspective of the smart transformers. Additionally, the paper also presents unified multi‑port systems used to interface various technologies with hybrid AC/DC grids, which are also foreseen to play an important role in future power grids (e.g., the unified interface of renewable energy sources and energy storage systems), including an analysis concerning unified multi‑port systems for AC or DC grids. Throughout the paper, these topics are presented and discussed in the context of future power grids. An exhaustive description of these technologies is made, covering the most relevant and recent structures and features that can be developed, as well as the challenges for the future power grids. Several scenarios are presented, encompassing the mentioned technologies, and unveiling a progressive evolution that culminates in the cooperative scope of such technologies for a disruptive vision of future power grids.

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“…Also, the open‐loop control strategy improves robustness and reduces the systematic control complexity. In addition, [24] and [25] apply open‐loop controlled SRCs to the DC SST application to obtain high efficiency, while the terminal voltage and transmission power cannot be regulated. In [26], a hybrid DC SST consisting of multiple SRCs and one or several DAB converters is proposed, which can regulate terminal voltage by DAB converter and achieve high efficiency thanks to SRCs.…”

Section: Introductionmentioning

confidence: 99%

A bidirectional three‐phase triple‐voltage LLC (T ² ‐LLC) resonant converter for DC/DC stage in solid state transformer and DC transformer applications

Shu

Chen

Jin

2022

IET Power Electronics

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This paper proposes a novel bidirectional three‐phase triple‐voltage LLC (T2‐LLC) resonant converter, which can be applied as the submodule of DC transformer (DCT) with fixed input and output terminal voltages. A novel series‐connected three‐phase circuit is adopted at medium voltage (MV) side to improve the voltage level of single submodule (SM) and decrease SM number. Therefore, the power density of DCT can be improved. Besides, the proposed converter is open‐loop controlled with fixed switching frequency, and it naturally realizes bidirectional power flow without changing controlling modes according to the power direction. However, the efficiency and voltage conversion ratio of proposed T2‐LLC converter are sensitive to resonant parameters, and consistency of three‐phase resonant parameters should be ensured to achieve three‐phase symmetrical operation. Therefore, design and optimization methods are proposed to realize ZVS turn‐on, reduce power losses and ensure fixed voltage conversion ratio. The operation principle and optimization method are presented and a 1000 V/333.3 V/5 kW platform is used to validate feasibility of the proposed converter.

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DC Solid State Transformer Based on Three-Level Power Module for Interconnecting MV and LV DC Distribution Systems

Cited by 39 publications

References 33 publications

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Review of a Disruptive Vision of Future Power Grids: A New Path Based on Hybrid AC/DC Grids and Solid-State Transformers

A bidirectional three‐phase triple‐voltage LLC (T ² ‐LLC) resonant converter for DC/DC stage in solid state transformer and DC transformer applications

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DC Solid State Transformer Based on Three-Level Power Module for Interconnecting MV and LV DC Distribution Systems

Cited by 39 publications

References 33 publications

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Coordination of mode switching control and SMES unit for low‐voltage ride‐through fulfillment of power electronic transformer

Review of a Disruptive Vision of Future Power Grids: A New Path Based on Hybrid AC/DC Grids and Solid-State Transformers

A bidirectional three‐phase triple‐voltage LLC (T 2 ‐LLC) resonant converter for DC/DC stage in solid state transformer and DC transformer applications

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Product

Resources

About

A bidirectional three‐phase triple‐voltage LLC (T ² ‐LLC) resonant converter for DC/DC stage in solid state transformer and DC transformer applications