• Title/Summary/Keyword: Isolated dc-dc converter

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A New Non-isolated Boost Converter with Two-Inductor and One-Transformer for Hybrid Electric Vehicle and Electric Vehicle (하이브리드 차량 및 전기 차량용 두 개의 인덕터와 하나의 변압기를 갖는 새로운 비절연형 부스트 컨버터)

  • Sung, Hyun-Wook;Park, Ki-Bum;Kim, Tae-Sung;Moon, Gun-Woo;Youn, Myung-Jung
    • Proceedings of the KIPE Conference
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    • 2007.07a
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    • pp.132-134
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    • 2007
  • 하이브리드 차량 및 전기차량 구동 모터의 권선저항에 의한 손실 및 모터의 크기를 줄이기 위해 고효율, 고승압형 DC-DC 컨버터 사용이 요구된다. 기존의 부스트 컨버터는 기생저항 성분에 의해 고승압이 불가능하여 변압기를 사용하여 승압비를 향상시킨 current-fed push-pull, current-fed full bridge, dual inductor-fed 부스트 컨버터 등으로 변형되어 사용되어 왔다. dual inductor-fed 부스트 컨버터의 경우 동일조건하에서 앞서 기술된 2가지 컨버터보다 2배의 승압비를 얻을 수 있으며 1차측 전류 스트레스가 낮은 장점을 가지고 있어 대전력, 고승압 응용에 적합하다. 하지만 변압기의 누설인덕턴스에 의한 써지성 전류/전압을 제한하기 위한 부가적인 snubber회로의 사용으로 효율을 떨어뜨리게 되는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 보완할 수 있는 새로운 2개의 인덕터와 1개의 변압기를 갖는 DC-DC 컨버터를 제안한다. 제안된 컨버터의 동작원리와 모드해석을 실시하고 최종적으로 400W, 42Vdc (Battery)/400Vdc (Electric Motor) 실험결과를 통해 이를 검증한다.

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Development of 3kW Hybrid ESS with Function of Emergency Power Supply (비상전원 기능을 갖는 3kW급 하이브리드 ESS 개발)

  • Yang, Seok-Hyun;Kim, Min-Jae;Choi, Se-Wan;Cho, Jun-Seok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.20 no.1
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    • pp.11-18
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    • 2015
  • This paper proposes a high-efficiency 3-kW hybrid ESS with emergency power supply. The proposed system enables efficient use of power from photovoltaic (PV) cells and energy storage system (ESS). The proposed system can operate as an uninterruptible power supply (UPS) when grid fault occurs, providing seamless transfer from grid-connected mode to stand-alone mode. The LLC converter for PV achieves ZVS turn-on of switches and ZCS turn-off of diodes, and the isolated bidirectional DC-DC converter for ESS achieves ZCS turn-off regardless of load condition, resulting in high efficiency. The efficiency and performance of the proposed hybrid ESS has been verified by a 3-kW prototype.

A Buck-Boost Converter-Based Bipolar Pulse Generator

  • Elserougi, Ahmed A.;Massoud, Ahmed M.;Ahmed, Shehab
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1422-1432
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    • 2017
  • This paper presents a buck-boost converter-based bipolar pulse generator, which is able to generate bipolar exponential pulses across a resistive load. The concept of the proposed approach depends on operating the involved buck-boost converters in discontinuous current conduction mode with high-voltage gain and enhanced efficiency. A full design of the pulse generator and its passive components is presented to ensure generating the pulses with the desired specifications (rise time, pulse width, and pulse magnitude) for a given load resistance and input dc voltage. In case of moderate pulsed output voltages (i.e. few of kV), one module of the presented bipolar generator can be employed. While in case of high-voltage pulsed output, multi-module version can be employed, where each module is fed from an isolated dc source and their outputs are connected in series. Simulation models for the proposed approach are built to elucidate their performance in case of one-module as well as multi-module based generator. Finally, a scaled-down prototype for one-module of buck-boost converter-based bipolar pulse generator is implemented to validate the proposed concept.

A New Zero-Voltage-Switching Two-Transformer Boost Converter (새로운 영전압 스위칭 2-트랜스포머 승압형 컨버터)

  • Park, Ki-Bum;Kim, Chong-Eun;Moon, Gun-Woo;Youn, Myung-Joong
    • Proceedings of the KIPE Conference
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    • 2005.07a
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    • pp.292-294
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    • 2005
  • A new zero voltage switching (ZVS) 2-transformer boost converter is proposed in this paper. The proposed converter has the advantage that the magnetizing inductor of the transformer acts for the boost inductor without additional inductor. Moreover, ZVS of main switches and auxiliary switches can be achieved, and the switch turn-off surge problem of conventional isolated boost converter is effectively solved. The operational principle, DC voltage gain, and ZVS characteristics are analyzed. To confirm the validity of the proposed converter, simulation results with 200w, 24Vdc/200Vdc specification are presented.

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Low Cost Single-Sourced Asymmetrical Cascaded H-Bridge Multilevel Inverter (저비용 단일전원 비대칭 Cascaded H-Bridge 멀티레벨 인버터)

  • Manoharan, Mohana Sundar;Ahmed, Ashraf;Lee, Chun-Gu;Park, Jong-Hu
    • Proceedings of the KIPE Conference
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    • 2015.07a
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    • pp.323-324
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    • 2015
  • Recently, asymmetrical cascaded H-bridge multilevel inverter started to be highlighted as an alternative for the symmetrical cascaded H-bridge. The topology has a small number of part count compared to the symmetrical with higher number of levels. However, it has a drawback of the modulation index limitation which is relatively higher than its symmetrical counterpart, which causes a necessity of an extra voltage pre-regulator. In this paper, the single-sourced pre-regulator is unified with an inner single switch DC/DC converter isolated by coupled inductor. It leads to cost and size reduction. The proposed topology is verified using simulation results.

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Battery Energy Storage System Based Controller for a Wind Turbine Driven Isolated Asynchronous Generator

  • Singh, Bhim;Kasal, Gaurav Kumar
    • Journal of Power Electronics
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    • v.8 no.1
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    • pp.81-90
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    • 2008
  • This paper presents an investigation of a voltage and frequency controller for an isolated asynchronous generator (IAG) driven. by a wind turbine and supplying 3-phase 4-wire loads to the isolated areas where a grid is not accessible. The control strategy is based on the indirect current control of the VSC (voltage source converter) using the frequency PI controller. The proposed controller consists of three single-phase IGBT (Insulated Gate Bipolar Junction Transistor) based VSC, which are connected to each phase of the IAG through three single phase transformers and a battery at their DC link. The controller has the capability of controlling reactive and active powers to regulate the magnitude and frequency of the generated voltage, harmonic elimination, load balancing and neutral current compensation. The proposed isolated system is modeled and simulated in MATLAB using Simulink and PSB (Power System Block-set) toolboxes to verify the performance of the controller.

Battery Energy Storage Based Voltage and Frequency Controller for Isolated Pico Hydro Systems

  • Singh, Bhim;Rajagopal, V.
    • Journal of Power Electronics
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    • v.9 no.6
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    • pp.874-883
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    • 2009
  • This paper deals with an integrated voltage and frequency (VF) controller for isolated asynchronous generators (IAG) driven by a constant power pico-hydro uncontrolled turbine feeding three-phase four-wire loads. The proposed VF controller is used to control the frequency and voltage of an IAG with load leveling. Such a VF controller is also known as an integrated electronic load controller (IELC) which is realized using an isolated star/polygon transformer with a voltage source converter (VSC) and a battery at its DC bus. The proposed generating system with a VFC is modeled and simulated in MATLAB along with Simulink and Simpower system (SPS) toolboxes. The simulated results are presented to demonstrate the performance of an isolated asynchronous generator feeding three-phase four-wire loads with neutral current compensation.

New Isolated Zero Voltage Switching PWM Boost Converter (새로운 절연된 영전압 스위칭 PWM 부스트 컨버터)

  • Cho, Eun-Jin;Moon, Gun-Woo;Jung, Young-Suk;Youn, Myung-Joong
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.535-538
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    • 1994
  • In this paper, an isolated ZVS-PWM boost converter is proposed for single stage line conversion. For power factor correction, we used the half bridge topology at the primary side of isolation transformer permitting switching devices to operate under ZVS by using circuit parastics and operating at a fixed duty ratio near 50%. Thus the relatively continuous input current distortion and small size input filter are also achievable. The ZVS-PWM boost operation of the proposed converter can be achieved by using the boost inductor $L_f$, main switch $Q_3$, and simple auxiliary circuit at the secondary side of isolation transformer. The secondary side circuit differ from a conventional PWM boost converter by introduction a simple auxiliary circuit. The auxiliary circuit is actived only during a short switching transition time to create the ZVS condition for the main switch as that of the ZVT-PWM boost converter. With a single stage, it is possible to achieve a sinusoidal line current at unity power factor as well as the isolated 48V DC output. Comparing to the two stage schemes, overall effiency of the proposed converter is highly improved due to the effective ZVS of all devices as well as single stage power conversion. Thus, it can be operated at high switching frequency allowing use of small size input filter. Minimum voltage and current stress make it high power application possible.

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A Coordinative Control Strategy for Power Electronic Transformer Based Battery Energy Storage Systems

  • Sun, Yuwei;Liu, Jiaomin;Li, Yonggang;Fu, Chao;Wang, Yi
    • Journal of Power Electronics
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    • v.17 no.6
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    • pp.1625-1636
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    • 2017
  • A power electronic transformer (PET) based on the cascaded H-bridge (CHB) and the isolated bidirectional DC/DC converter (IBDC) is capable of accommodating a large scale battery energy storage system (BESS) in the medium-voltage grid, and is referred to as a power electronic transformer based battery energy storage system (PET-BESS). This paper investigates the PET-BESS and proposes a coordinative control strategy for it. In the proposed method, the CHB controls the power flow and the battery state-of-charge (SOC) balancing, while the IBDC maintains the dc-link voltages with feedforward implementation of the power reference and the switch status of the CHB. State-feedback and linear quadratic Riccati (LQR) methods have been adopted in the CHB to control the grid current, active power and reactive power. A hybrid PWM modulating method is utilized to achieve SOC balancing, where battery SOC sorting is involved. The feedforward path of the power reference and the CHB switch status substantially reduces the dc-link voltage fluctuations under dynamic power variations. The effectiveness of the proposed control has been verified both by simulation and experimental results. The performance of the PET-BESS under bidirectional power flow has been improved, and the battery SOC values have been adjusted to converge.

Isolated Bidirectional CLLC Resonant Converter using Digital Control for LVDC Distribution System (디지털로 제어되는 저압 직류 배전용 절연형 양방향 CLLC 공진형 컨버터)

  • Jung, Jee-Hoon;Kim, Ho-Sung;Ryu, Myung-Hyo;Kim, Jong-Hyun;Kim, Tae-Jin;Baek, Ju-Won
    • Proceedings of the KIPE Conference
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    • 2012.07a
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    • pp.379-380
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    • 2012
  • A bidirectional full-bridge CLLC resonant converter using a digital control method is proposed for a LVDC power distribution system. This converter can operate under high power conversion efficiency since the CLLC resonant network has soft switching capability for primary switches and output rectifiers. In addition, the power conversion efficiency of any directions is exactly the same as each other because of the symmetric structure of the converter. Intelligent digital control methods are proposed to regulate output voltage under any power flow directions. A 5kW prototype converter was designed for a high-frequency galvanic isolation of 380V dc buses using a digital signal processor to verify the performance of the proposed topology and algorithms.

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