• Title/Summary/Keyword: Synchronous converter

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High Efficiency PFC AC/DC Converter with Synchronous Rectifier (동기 정류기를 이용한 고효율 역률보상형 AC/DC 컨버터)

  • 박한웅
    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.266-269
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    • 2000
  • This paper presents a novel single-stage unity power factor converter which features the reduced switching losses by zero-voltage switching and zero-current switching (ZVZCS). Hence the turn-on and turn-off losses of switches are sufficiently reduced. And the reduced conduction losses are achieved by the elimination of one leg of front-end rectifier. And low on-resistance MOSFETs (Synchronous Rectifier) are used in the rectifier at the secondary side of high frequency transformer instead of diodes. Theoretical analysis simulated results of a AC to DC 150W(5V, 30A) converter are presented.

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A Study on Excitation System for Synchronous Generator using Current Mode Controlled PWM Converter (전류제어형 PWM컨버터를 이용한 동기발전기용 여자시스템에 관한 연구)

  • 장수진;류동균;서민성;김준호;원충연;이진국
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.3
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    • pp.32-39
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    • 2003
  • The output voltage of synchronous generator is regulated constantly by field current control in excitation system High frequency PWM converter (current control mode buck converter) type excitation systam fer synchronous generator is able to control exciter current when the load change happened. This paper deals with the design and evaluation of the excitation system for a synchronous generator to improve the steady state and transient stability. The simulation and experimental results show that the proposed excitation system is able to improve the response time by the DVR(digital voltage regulator) of 50[kW] synchronous generator.

2-stage 3-phase PWM AC/DC Converter for Unity Power Factor Drive of Synchronous Generator (단위역률동작을 위한 동기 발전기 여자 시스템용 2단 3상 PWM AC/DC 컨버터)

  • Lee, Sang-Hun;Kim, Tae-Hyoung;Lee, Dong-Hee;Ahn, Jin-Woo
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2007.05a
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    • pp.187-192
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    • 2007
  • The terminal voltage of a synchronous generator is maintained by the field current control of excitation system Generally AC/DC converter which is component of AVR(Automatic Voltage Regulator) system for excitation current control is connected to diode rectifier and DC/DC converter system In the case of diode rectifier system of phase controlled converter, AC/DC converter has low power factor and some low order harmonics in the line current. In this paper, two-stage three-phase PWM AC/DC converter is studied to solve these problems, The proposed method is verified by the computer simulations and experimental results in prototype generation system.

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AC-DC Zeta Converter for Power Quality Improvement in Direct Torque Controlled PMSM Drive

  • Singh Bhim;Singh B.P.;Dwivedi Sanjeet
    • Journal of Power Electronics
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    • v.6 no.2
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    • pp.146-162
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    • 2006
  • This paper deals with the analysis, design and implementation of an AC-DC Zeta converter in discontinuous current mode (DCM) of operation used for power quality improvement at AC mains in direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drives. The designed Zeta converter feeds a direct torque controlled PMSM drive system. Modeling and simulation is carried out in a standard PSIM software environment. Test results are obtained on the developed prototype Zeta converter using DSP ADMC401. The results obtained demonstrate the effectiveness of the Zeta converter in improving power quality at AC mains in the PMSM drive system.

Dynamic Performance of HVDC According to Excitation System Characteristics of Synchronous Compensator in a Weak AC System (약한 AC 계통에서 동기조상기용 여자 시스템 특성에 따른 HVDC 과도 특성)

  • Kim, Chan-Gi;Kim, Jeong-Bu;Sim, Eung-Bo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.6
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    • pp.431-440
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    • 2000
  • This paper analyses the dynamic performance of HVDC System connected to a weak AC system for various exciter characteristics of synchronous machines connected at the converter bus. Conventionally capacitors are used to supply reactive power requirement at a strong converter bus. But the installation of synchronous machine is essential in a isolated weak network to re-start after a shutdown of HVDC and to increase system strength. The dynamic performance of a synchronous machine depends on the characteristics depends of its exciter. In this paper, several exciter types are used to investigate their effect on the dynamic performance of the HVDC system and modifications to standard exciter topologies are suggested to mitigate observed problems.

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A Study on the Efficiency Prediction of Low-Voltage and High-Current dc-dc Converters Using GaN FET-based Synchronous Rectifier (GaN FET 기반 동기정류기를 적용한 저전압-대전류 DC-DC Converter 효율예측)

  • Jeong, Jea-Woong;Kim, Hyun-Bin;Kim, Jong-Soo;Kim, Nam-Joon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.4
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    • pp.297-304
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    • 2017
  • The purpose of this paper is to analyze losses because of switching devices and the secondary side circuit diodes of 500 W full bridge dc-dc converter by applying gallium nitride (GaN) field-effect transistor (FET), which is one of the wide band gap devices. For the detailed device analysis, we translate the specific resistance relation caused by the GaN FET material property into algebraic expression, and investigate the influence of the GaN FET structure and characteristic on efficiency and system specifications. In addition, we mathematically compare the diode rectifier circuit loss, which is a full bridge dc-dc converter secondary side circuit, with the synchronous rectifier circuit loss using silicon metal-oxide semiconductor (Si MOSFET) or GaN FET, which produce the full bridge dc-dc converter analytical value validity to derive the final efficiency and loss. We also design the heat sink based on the mathematically derived loss value, and suggest the heat sink size by purpose and the heat divergence degree through simulation.

A Study on Excitation System for Synchronous Generator Using Two State Three Phase PWM AC/DC Converter (2단 3상 PWM AC/DC 컨버터를 이용한 동기발전기 여자제어시스템)

  • Lee, Sang-Hun;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.3
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    • pp.96-106
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    • 2007
  • The terminal voltage of a synchronous generator is maintained by the field current control of excitation system. Generally AC/DC converter which is component of AVR(Automatic Voltage Regulator) system for excitation current control is connected to diode rectifier and DC/DC converter system. In the case of diode rectifier system of phase controlled converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, two stage three phase PWM AC/DC converter is studied to solve these problems. The characteristics of a proposed converter reduces the harmonics and reactive power of the distribution line and has fast dynamic response in transient period using boost converter and current control mode buck converts. The proposed method is verified by the computer simulation and experimental results in prototype generation system.

A Study on Open-frame Type DC-DC Converter Module for Low-Voltage High-Current Applications (저전압 대전류용 개방형 DC-DC 컨버터 모듈에 관한 연구)

  • 안태영;황선민;조인호
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.4
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    • pp.183-190
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    • 2003
  • We report the performance of an open-frame type low-voltage high-current DC-DC converter module developed using an active clamp forward converter circuit and current doubler rectifier. The converter module is designed with the specifications of an 1.8V output voltage, 25A output current, and 36-75V input voltage. The synchronous rectifier is used to reduce the conduction fuss at high current level and current-mode control is adapted to enhance the flexibility in the system configuration. A prototype converter module is successfully implemented within 10mm height and half brick size (58${\times}$61mm), and recorded an 84% efficiency and 4% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

A Study on Open-frame Type DC-DC Converter Module for Low-Voltage High-Current Applications (저전압 대전류용 개방형 DC-DC 컨버터 모듈에 관한 연구)

  • 안태영;황선민;조인호
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.4
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    • pp.183-183
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    • 2003
  • We report the performance of an open-frame type low-voltage high-current DC-DC converter module developed using an active clamp forward converter circuit and current doubler rectifier. The converter module is designed with the specifications of an 1.8V output voltage, 25A output current, and 36-75V input voltage. The synchronous rectifier is used to reduce the conduction fuss at high current level and current-mode control is adapted to enhance the flexibility in the system configuration. A prototype converter module is successfully implemented within 10mm height and half brick size (58×61mm), and recorded an 84% efficiency and 4% voltage regulation for the entire input voltage range, thereby demonstrating its application potentials to future telecommunication electronics.

Cost-Effective Converters for Micro Wind Turbine Systems using PMSG

  • Park, Hong-Geuk;Lee, Dong-Choon;Kim, Heung-Geun
    • Journal of Power Electronics
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    • v.8 no.2
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    • pp.156-162
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    • 2008
  • This paper proposes a low-cost power converter for micro wind turbine systems using permanent magnet synchronous generators (PMSG). The proposed converter consists of a two-leg three-phase PWM inverter for the generator control and a single-phase half-bridge PWM converter which is connected to the utility grid. For the two separate DC-link voltages, a balancing control is added and the adverse effect of the DC-link voltage ripples on the inverter output voltage is compensated. The control performance of the proposed converter topology for the micro wind turbine system is shown by the simulation results using PSIM software.