• Title/Summary/Keyword: solid-state transformer

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A Study on Multi-level Converter Based on Distribution Active Hybrid Solid State Transformer (멀티레벨 컨버터 기반 배전용 능동형 하이브리드 반도체 변압기에 대한 연구)

  • Yun, Chun-gi;Cho, Younghoon
    • Proceedings of the KIPE Conference
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    • 2018.07a
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    • pp.84-86
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    • 2018
  • Active hybrid solid state transformer(AHSST) is newly emerging as a device to maintan the power quality of power distribution. AHSST has a simple structure in which a power electronics device is connected in series to a conventional distribution transformer. The connected power electronics device maintains the constant voltage regardless of the primary grid voltage fluctuation through the secondary voltage control to improve the power quality. It also has a simple structure compare to conventional solid state transformer system and can achieve the same performance with fractionally-rated converter. This paper proposes an multi-level converter based on AHSST system that has a simpler control method and wider voltage control range than the conventional AHSST. The proposed system is verified by simulations.

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Operation-Profile Based Lifetime Evaluation of Power Semiconductor Devices in Solid-State Transformer for Urban Railway Vehicles (운행 프로파일 기반 도시철도차량용 반도체 변압기의 전력 반도체 소자 수명 평가)

  • Choi, Ui-Min;Park, Jin-Hyuk;Kim, Myung-Yong;Lee, June-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.6
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    • pp.496-502
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    • 2020
  • The reliability of a solid-state transformer (SST) is one of the important aspects to consider when replacing a conventional low-frequency passive transformer with SST for urban railway vehicles. Lifetime evaluation of SST in the design phase is therefore essential in guaranteeing a certain SST reliability. In this study, a lifetime evaluation of power semiconductor devices in SST is performed with respect to temperature stress. For a case study, a 3 MW SST with three kinds of power modules (one IGBT module and two SiC-MOSFET modules) is used for the lifetime estimation under the operation profile of urban railway vehicles.

A Study on the 3-phase 13.2 kV Solid State Transformer for the DC Distribution (직류 배전망 연계를 위한 3상 13.2kV급 반도체 변압기 시스템에 대한 연구)

  • Jeong, Dong-Keun;Yun, Hyeok-Jin;Park, Si-Ho;Kim, Ho-Sung;Kim, Myoung-Ho;Ryu, Myung-Hyo;Baek, Ju-Won
    • The Transactions of the Korean Institute of Power Electronics
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    • v.26 no.5
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    • pp.315-324
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    • 2021
  • A solid state transformer (SST) that can interface an MVAC of three-phase 13.2 kV and a 1.5 kV DC distribution. SST consists of an AC/DC converter and a DC/DC converter with a high-frequency isolation transformer (HFIT). The AC/DC converter consists of cascaded NPC full-bridge to cope with the MVAC. The DC/DC converter applies a quad active bridge (QAB) topology to reduce the number of the HFIT. Topology analysis and controller design for this specific structure are discussed. In addition, the insulation of HFIT used in DC/DC converters is considered. The discussion is validated using a 300 kVA three-phase SST prototype.

Design Optimization of Bi-directional Dual Active Bridge DC/DC Converter for Solid State Transformer (Solid State Transformer를 위한 양방향 Dual Active Bridge DC/DC 컨버터 최적 설계)

  • Choi, Hyun-Jun;Park, Hwa-Pyeong;Jung, Jee-Hoon
    • Proceedings of the KIPE Conference
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    • 2014.07a
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    • pp.197-198
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    • 2014
  • 본 논문에서는 양방향 DC-DC Dual Active Bridge (DAB) 컨버터의 수학적 모델로부터 컨버터의 변압기와 결합 인덕터의 최적 설계 방법을 제안한다. DAB컨버터는 1차 측과 2차 측이 동일한 구조를 가진 고효율 절연형 컨버터로써, Soft Switching이 쉽게 구현되고, 양방향으로 Power를 전달 할 수 있는 장점으로 널리 사용되고 있다. 본 논문에서 제안하는 컨버터는 Solid State Transformer (SST) 용으로 변압기 1차 측과 2차 측의 턴 비가 동일한 구조로써, 최대의 ZVS영역을 확보하고, 전력 변환 효율을 극대화 할 수 있다. 3.3 kW급 시제품을 제작하여 제안하는 컨버터의 타당성을 검증하고자 한다.

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Practical Design Methodology of Dual Active Bridge Converter as Isolated Bi-directional DC-DC Converter for Solid State Transformer (Solid State Transformer를 위한 양방향 Dual Active Bridge DC-DC 컨버터의 설계 기법)

  • Choi, Hyun-Jun;Lee, Won-Bin;Jung, Jee-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.2
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    • pp.102-108
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    • 2017
  • Proper design guides are proposed for a practical dual-active bridge (DAB) converter based on the mathematical model on the steady state. The DAB converter is popular in bidirectional application due to its zero-voltage capability and easy bidirectional operation for seamless control, high efficiency, and performance. Some design considerations are taken to overcome the limitation of the DAB converter. The practical design methodology of power stage is discussed to minimize the conduction and switching losses of the DAB converter. Small-signal model and frequency response are derived and analyzed based on the generalized average method, which considers equivalent series resistance, to improve the dynamics, stability, and reliability with voltage regulation of the practical DAB converter. The design of closed-loop control is discussed by the derived small-signal model to obtain the pertinent gain and phase margin in steady-state operation. Experimental results of a 3.3 kW prototype of DAB converter demonstrate the validity and effectiveness of the proposed methods.

AC TO AC Direct Voltage Conversion Using A Solid State Transformer

  • Um, Keehong
    • International Journal of Internet, Broadcasting and Communication
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    • v.5 no.1
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    • pp.6-8
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    • 2013
  • In this paper, we present an intelligent digital controller circuit which can be applied to automatic voltage regulation. The proposed solid state transformer with Pspice simulation model shows that our approach is very efficient and produces the desirable output. It is comparable to an ordinary magnetic coupled autotransformer.

Secondary Indirect Constant Voltage Control Technique for Hybrid Solid State Transformer using Primary Side Information (하이브리드 반도체 변압기의 1차측 정보를 이용한 2차측 간접 정전압 제어 기법)

  • Lee, Taeyeong;Yun, Chun-Gi;Cho, Younghoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.5
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    • pp.420-423
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    • 2020
  • This study proposes an indirect constant voltage control algorithm for hybrid solid-state transformers (HSSTs) by using primary side information. Considering the structure of HSSTs, measuring voltage and current information on the primary side of a transformer is necessary to control the converter and inverter of the power converter. The secondary side output voltage is measured to apply the conventional secondary side constant voltage control algorithm, and thus, the digital control board requires the same rated insulation voltage as that of the transformer. To solve this problem, the secondary voltage of the transformer obtained from the tap voltage is used. Moreover, output voltage decreases as load increases because the proposed indirect constant voltage control scheme does not consider the cable impedance between the secondary output terminal and the load. This study also proposes a technique for compensating the secondary output voltage by using the primary current of the transformer and the resistance value of the cable. An experiment is conducted using a scale-down HSST prototype consisting of a 660 V/220 V tap transformer. The problem of the proposed indirect constant voltage control strategy and the improvement effect due to the application of the compensation method are compared using the derived experimental results.

Design and Implementation of a Power Conversion Module for Solid State Transformers using SiC MOSFET Devices (배전용 반도체 변압기 구현을 위한 SiC MOSFET 기반 전력변환회로 단위모듈 설계에 관한 연구)

  • Lim, Jeong-Woo;Cho, Young-Hoon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.2
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    • pp.109-117
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    • 2017
  • This paper describes the design and implementation of a unit module for a 10 kVA class 13.2 kV/220 V unidirectional solid-state transformer (SST) with silicon-carbide metal-oxide-semiconductor field-effect transistors. The proposed module consists of an active-front-end (AFE) converter to interface 1320 V AC voltage source to 2500 V DC link and an isolated resonant DC-DC converter for 500 V low-voltage DC output. The design approaches of the AFE and the isolated resonant DC-DC converters are addressed. The control structures of the converters are described as well. The experiments for the converters are performed, and results verify that the proposed unit module can be successfully adopted for the entire SST operation.