• Title/Summary/Keyword: Transformer

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A High Efficiency Controller IC for LLC Resonant Converter in 0.35 μm BCD

  • Hong, Seong-Wha;Kim, Hong-Jin;Park, Hyung-Gu;Park, Joon-Sung;Pu, Young-Gun;Lee, Kang-Yoon
    • Journal of Power Electronics
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    • v.11 no.3
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    • pp.271-278
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    • 2011
  • This paper presents a LLC resonant controller IC for secondary side control without external active devices to achieve low profile and low cost LED back light units. A gate driving transformer is adopted to isolate the primary side and the secondary side instead of an opto-coupler. A new integrated dimming circuitry is proposed to improve the dynamic current control characteristic and the current density of a LED for the brightness modulation of a large screen LCD. A dual-slope clock generator is proposed to overcome the frequency error due to the under shoot in conventional approaches. This chip is fabricated using 0.35 ${\mu}m$ BCD technology and the die size is $2{\times}2\;mm^2$. The frequency range of the clock generator is from 50 kHz to 500 kHz and the range of the dead time is from 50 ns to 2.2 ${\mu}s$. The efficiency of the LED driving circuit is 97 % and the current consumption is 40 mA for a 100 kHz operation frequency from a 15 V supply voltage.

A Protection Circuit for the Power Supply of a Gas Discharge Lamp

  • Kim, Ho-Sung;Kim, Jong-Hyun;Baek, Ju-Won;Yoo, Dong-Wook;Jung, Hye-Man;Kim, Hee-Je
    • Journal of Power Electronics
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    • v.10 no.6
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    • pp.777-783
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    • 2010
  • In order to drive gas discharge lamps, DC-AC converters with a LCC resonant tank, whose output voltage is adjusted by a variable frequency control are frequently used. However, when they are activated by varying the operating frequency, converters are frequently damaged by unstable operation, due to the rising and falling of the operating frequency near the resonant frequency. To solve this problem, a simple protection circuit for the power supply of a gas discharge lamp is proposed in this paper. This circuit senses the primary current of the main transformer. Using this protection circuit, the operating frequency of the lamp driving inverter system is kept close to and on the right side of the resonant frequency and the inverter is always operated in the ZVS condition. The resulting stable variable frequency operation allows various gas discharge lamps to be tested without the risk of damaging the main switches, because the protection circuit can protect the power MOSFETs of bridge converters from abnormal conditions. The validity and effectiveness of the proposed protection circuit are verified through the experimental results.

Single Power-conversion AC-DC Converter with High Power Factor (고역률을 갖는 단일 전력변환 AC-DC 컨버터)

  • Cho, Yong-Won;Park, Chun-Yoon;Kwon, Bong-Hwan
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.1
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    • pp.23-30
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    • 2014
  • This paper proposes a single power-conversion ac-dc converter with a dc-link capacitor-less and high power factor. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a suitable control algorithm for the proposed converter. The proposed converter provides single power-conversion by using the proposed control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor of 0.995 and maximum efficiency of 95.1% at the full-load. The operation principle of the converter is analyzed and verified. Experimental results for a 400W ac-dc converter at a constant switching frequency of 50kHz are obtained to show the performance of the proposed converter.

Suppression of Common-Mode Voltage in a Multi-Central Large-Scale PV Generation Systems for Medium-Voltage Grid Connection (중전압 계통 연계를 위한 멀티 센트럴 대용량 태양광 발전 시스템의 공통 모드 전압 억제)

  • Bae, Young-Sang;Kim, Rae-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.19 no.1
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    • pp.31-40
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    • 2014
  • This paper describes an optimal configuration for multi-central inverters in a medium-voltage (MV) grid, which is suitable for large-scale photovoltaic (PV) power plants. We theoretically analyze a proposed common-mode equivalent model for problems associated with multi-central transformerless-type three-phase full bridge(3-FB) PV inverters employing two-winding MV transformers. We propose a synchronized PWM control strategy to effectively reduce the common-mode voltages that may simultaneously occur. In addition, we propose that the existing 3-FB topology may also have the configuration of a multi-central inverter with a two-winding MV transformer by making a simple circuit modification. Simulation and experimental results of three 350kW PV inverters in a multi-central configuration verify the effectiveness of the proposed synchronization control strategy. The modified transformerless-type 3-FB topology for a multi-central PV inverter configuration is verified using an experimental prototype of a 100kW PV inverter.

Development Of High Efficiency Boost DC/DC Converter For EV (전기자동차용 고효율 승압형 DC/DC 컨버터 개발)

  • Choi, Mi-Seon;Song, Sung-Geun;Park, Sung-Jun;Kim, Dae-Kyong;Kim, Yong-Gu
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.2
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    • pp.127-133
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    • 2010
  • In the paper, reactorless high efficiency boost DC/DC converter for EV is proposed. In proposed converter, improves efficiency because decrease power loss when the switches are turned on/off using zero current switching (ZCS) at all switch of primary full bridge. By replacing reactance ingredients of L-C resonance circuit for ZCS with leakage inductance ingredients of high frequency transformer, it reduces system size and expense because of not add special reactor. For validity verification of proposed converter, in the paper implements simulation using PSIM and perform experiment by making 5KW DC/DC converter. In experimental results, efficiency of proposed converter conformed superiority.

Efficiency Optimization with a Novel Magnetic-Circuit Model for Inductive Power Transfer in EVs

  • Tang, Yunyu;Zhu, Fan;Ma, Hao
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.309-322
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    • 2018
  • The technology of inductive power transfer has been proved to be a promising solution in many applications especially in electric vehicle (EV) charging systems, due to its features of safety and convenience. However, loosely coupled transformers lead to the system efficiency not coming up to the expectation at the present time. Therefore, at first, the magnetic core losses are calculated with a novel magnetic-circuit model instead of the commonly used finite-element-method (FEM) simulations. The parameters in the model can be obtained with a one-time FEM simulation, which makes the calculation process expeditious. When compared with traditional methods, the model proposed in the paper is much less time-consuming and relatively accurate. These merits have been verified by experimental results. Furthermore, with the proposed loss calculation model, the system is optimized by parameter sweeping, such as the operating frequency and winding turns. Specifically, rather than a predesigned switching frequency, a more efficiency-optimized frequency for the series-parallel (SP) compensation topology is detected and a detailed investigation has been presented accordingly. The optimized system is capable of an efficiency that is greater than 93% at a coil separation distance of 200mm and coil dimensions of $600mm{\times}400mm$.

Pulse-width Adjustment Strategy for Improving the Dynamic Inductor Current Response Performance of a Novel Bidirectional DC-DC Boost Converter

  • Li, Mingyue;Yan, Peimin
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.34-44
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    • 2018
  • This paper presents a pulse-width adjustment (PWA) strategy for a novel bidirectional DC-DC boost converter to improve the performance of the dynamic inductor current response. This novel converter consists of three main components: a full-bridge converter (FBC), a high-frequency isolated transformer with large leakage inductance, and a three-level voltage-doubler rectifier (VDR). A number of scholars have analyzed the principles, such as the soft-switching performance and high-efficiency characteristic, of this converter based on pulse-width modulation plus phase-shift (PPS) control. It turns out that this converter is suitable for energy storage applications and exhibits good performance. However, the dynamic inductor current response processes of control variable adjustment is not analyzed in this converter. In fact, dc component may occur in the inductor current during its dynamic response process, which can influence the stability and reliability of the converter system. The dynamic responses under different operating modes of a conventional feedforward control are discussed in this paper. And a PWA strategy is proposed to enhance the dynamic inductor current response performance of the converter. This paper gives a detailed design and implementation of the PWA strategy. The proposed strategy is verified through a series of simulation and experimental results.

Soft Switching Multiple Output Charger By Using Novel Time Division Multiple Control Technique (새로운 시분할 다중 제어 기법을 이용한 소프트 스위칭 다중 출력 충전기)

  • Tran, Van-Long;Choi, Woojin
    • Proceedings of the KIPE Conference
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    • 2014.07a
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    • pp.191-192
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    • 2014
  • Multiple output converters (MOCs) are widely used for applications which require various levels of the output voltages due to their benefits in cost, volume, and efficiency. However, most of the MOCs developed so far can regulate only one output tightly and require as many secondary windings in the transformer as the number of the outputs. In this paper, a novel Time Division Multiple Control (TDMC) method to regulate all the outputs in high precision is proposed and applied for the multiple output battery charger based on the phase shift full bridge topology to charge a multiple number of batteries at one time. The proposed converter can charge three different kinds of batteries or same kind of batteries in different state of charges (SOCs) by using constant current/constant voltage (CC/CV) charge mode independently. At the same time it can provide an even degree of tight regulation for each output to satisfy the strict ripple requirement of the battery. The validity and feasibility of the proposed method are verified through the experiments.

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A Study on the Design and Fabrication for Partial Discharge Measurment in 22.9kV Underground Power Cable using Planar Loop Sensor (22.9kV급 지중전력케이블의 부분방전 측정을 위한 평면루프센서 설계 및 제작 연구)

  • Shin, Dong-Hoon;Lim, Kwang-Jin;Lwin, Kyawsoe;Park, Noh-Joon;Park, Dae-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.210-211
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    • 2007
  • The objective of this paper is to effectively detect partial discharges in underground power cables. In this field, we have been usually applied several sensors for such partial discharges. This study used a type of beyond compare antenna based on the influence of background noises. Also, we designed a new structure that is able to easily apply in the adhesion of planar loop types for underground power cables in measurement sensitiveness elevation. A high frequency simulation tool (CST-MWS) was applied to the antenna used in this study, and it was used to evaluate certain characteristics. We fabricated an antenna using the simulation data obtained from a specific test. After checking the sensitivity of this Planar Loop Sensor in the Lab, it was tested in an actual site. This paper analyzed the data as a part of time and frequency domain using an oscilloscope and spectrum analyzer, respectively.

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Highly Productive Process Technologies of Cantilever-type Microprobe Arrays for Wafer Level Chip Testing

  • Lim, Jae-Hwan;Ryu, Jee-Youl;Choi, Woo-Chang
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.2
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    • pp.63-66
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    • 2013
  • This paper describes the highly productive process technologies of microprobe arrays, which were used for a probe card to test a Dynamic Random Access Memory (DRAM) chip with fine pitch pads. Cantilever-type microprobe arrays were fabricated using conventional micro-electro-mechanical system (MEMS) process technologies. Bonding material, gold-tin (Au-Sn) paste, was used to bond the Ni-Co alloy microprobes to the ceramic space transformer. The electrical and mechanical characteristics of a probe card with fabricated microprobes were measured by a conventional probe card tester. A probe card assembled with the fabricated microprobes showed good x-y alignment and planarity errors within ${\pm}5{\mu}m$ and ${\pm}10{\mu}m$, respectively. In addition, the average leakage current and contact resistance were approximately 1.04 nA and 0.054 ohm, respectively. The proposed highly productive microprobes can be applied to a MEMS probe card, to test a DRAM chip with fine pitch pads.