• 제목/요약/키워드: AC and DC Power Applications

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NPC 인버터를 이용한 3상 동기형 SVC의 해석 및 설계 (Analysis and Design of a Three-Phase Synchronous Solid-state Var Compensator using Neutral-Point-Clamped Inverter)

  • 임수생;이은웅;김성헌;이동주
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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    • pp.42-45
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    • 1997
  • A synchronous solid-state var compensator(SSVC) system which employs a three-phase neutral-point-darned (NPC) inverter is presented and analyzed for high voltage and high power applications. The proposed SSVC system can compensate for leading and lagging displacement factor. An optimal pulse-width-modulation (PWM) is used as a means of reducing the size of reactive components. A equivalent model is obtained using DQ-transform, and the characteristic of open-loop system are archived from DC and AC analyzes. A $\alpha$ phase-shift control is suggested using a self-controlled dc bus.

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Advanced Microwave Plasma Technology for Liquid Treatment

  • Toyoda, Hirotaka;Takahashi, T.;Takada, N.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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    • pp.121.1-121.1
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    • 2014
  • Recently, much attention has been given to plasma production under liquid and its applications [1]. However, most of plasma production techniques reported so far utilize high voltage dc, ac, rf or microwave power [2], where damage to discharge electrodes and small discharge volume are remained issues. As an alternative of plasma production method under liquid, we have proposed pulsed microwave excited plasma using slot antenna, where damage to the slot electrode can be minimized and plasma volume can be increased. We have also reported improvement of treatment efficiency with use of reduced-pressure condition during the discharge [3]. To realize low pressure conditions in liquid, various alternative technique can be considered. One possible technique is simultaneous injection of microwave power and ultrasonic wave. Ultrasonic wave induces pressure fluctuation with the wave propagation and is so far used for cavitation production in the water. We propose utilization of reduced pressure induced by ultrasonic cavitation for improvement of the plasma production. Correlation between the plasma production and the ultrasonic power will be discussed.

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A Single-Stage LED Tube Lamp Driver with Input-Current Shaping for Energy-Efficient Indoor Lighting Applications

  • Cheng, Chun-An;Chang, Chien-Hsuan;Cheng, Hung-Liang;Chung, Tsung-Yuan;Tseng, Ching-Hsien;Tseng, Kuo-Ching
    • Journal of Power Electronics
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    • 제16권4호
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    • pp.1288-1297
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    • 2016
  • This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

A Ripple Rejection Inherited RPWM for VSI Working with Fluctuating DC Link Voltage

  • Jarin, T.;Subburaj, P.;Bright, Shibu J V
    • Journal of Electrical Engineering and Technology
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    • 제10권5호
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    • pp.2018-2030
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    • 2015
  • A two stage ac drive configuration consisting of a single-phase line commutated rectifier and a three-phase voltage source inverter (VSI) is very common in low and medium power applications. The deterministic pulse width modulation (PWM) methods like sinusoidal PWM (SPWM) could not be considered as an ideal choice for modern drives since they result mechanical vibration and acoustic noise, and limit the application scope. This is due to the incapability of the deterministic PWM strategies in sprawling the harmonic power. The random PWM (RPWM) approaches could solve this issue by creating continuous harmonic profile instead of discrete clusters of dominant harmonics. Insufficient filtering at dc link results in the amplitude distortion of the input dc voltage to the VSI and has the most significant impact on the spectral errors (difference between theoretical and practical spectra). It is obvious that the sprawling effect of RPWM undoubtedly influenced by input fluctuation and the discrete harmonic clusters may reappear. The influence of dc link fluctuation on harmonics and their spreading effect in the VSI remains invalidated. A case study is done with four different filter capacitor values in this paper and results are compared with the constant dc input operation. This paper also proposes an ingenious RPWM, a ripple dosed sinusoidal reference-random carrier PWM (RDSRRCPWM), which has the innate capacity of suppressing the effect of input fluctuation in the output than the other modern PWM methods. MATLAB based simulation study reveals the fundamental component, total harmonic distortion (THD) and harmonic spread factor (HSF) for various modulation indices. The non-ideal dc link is managed well with the developed RDSRRCPWM applied to the VSI and tested in a proto type VSI using the field programmable gate array (FPGA).

The Overview of a Digital Power System Simulator for Large Power System Analysis

  • Kim, Tae-Kyun;Kim, Yong-Hak;Shin, Jeong-Hoon;Choo, Jin-Boo
    • KIEE International Transactions on Power Engineering
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    • 제3A권2호
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    • pp.93-99
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    • 2003
  • This paper deals with the development and testing of a large-scale, realtime digital power system simulator for the Korean Electric Power Corporation. The KEPS Simulation Center is located at KEPCO's research center (KEPRI) in Taejon, South Korea and has been operated since September 2001. The KEPS Simulation Center includes a wide range of off line power system simulation and analysis tools, as well as an advanced realtime digital simulator for the study of large scale AC and DC system performance. Because the application scope of the KEPS realtime simulator is broad and because the network models being considered are significantly larger and more complex than in traditional realtime simulator applications, many developments and tests have been required during the course of the project. In this paper, the authors describe some of these developments and present results from various benchmark tests that have been performed.

Development of the High Input Voltage Self-Power for LVDC

  • Kim, Kuk-Hyeon;Kim, Soo-Yeon;Choi, Eun-Kyung;HwangBo, Chan;Park, Seong-Mi;Park, Sung-Jun
    • 한국산업융합학회 논문집
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    • 제24권4_1호
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    • pp.387-395
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    • 2021
  • Distributed resources such as renewable energy sources and ESS are connected to the low voltage direct current(LVDC) distribution network through the power conversion system(PCS). Control power is required for the operation of the PCS. In general, controller power is supplied from AC power or DC power through switch mode power supply(SMPS). However, the conventional SMPS has a low input voltage, so development and research on high input voltage self-power suitable for LVDC is insufficient. In this paper, to develop Self-Power that can be used for LVDC, the characteristics of the conventional topology are analyzed, and a series-input single-output flyback converter using a flux-sharing transformer for high voltage is designed. The high input voltage Self-Power was designed in the DCM(discontinuous current mode) to reduce the switching loss and solve the problem of current dissipation. In addition, since it operates even at low input voltage, it can be applied to many applications as well as LVDC. The validity of the proposed high input voltage self-power is verified through experiments.

Controlled-Type ZVS Technique without Auxiliary Components for Micro-inverters

  • Zhang, Qian;Zhang, Dehua;Hu, Haibing;Shen, John;Batarseh, Issa
    • Journal of Power Electronics
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    • 제13권6호
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    • pp.919-927
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    • 2013
  • This paper proposes a Boundary Current Mode (BCM) control scheme to realize soft switching on a conventional single phase full bridge DC/AC inverter. This technique with the advantages of no auxiliary components, low cost, high efficiency, and simple in control, is attractive for micro-inverter applications. The operation principle and characteristic waveforms of the proposed soft switching technique are analyzed in theory. A digital controller is provided based on that theory. To balance the requirements of efficiency, switching frequency, and inductor size, the design considerations are discussed in detail to guide in BCM inverter construction. A 150W prototype is built under these guidelines to implement the BCM control scheme. Simulation and experiment results demonstrate the feasibilities of the proposed soft switching technique.

Novel Topologies Implementation for SRM Drive with Conventional Type Structure

  • Yoon, Yong-Ho;Won, Chung-Yuen;Kim, Jae-Moon
    • 조명전기설비학회논문지
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    • 제21권9호
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    • pp.47-56
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    • 2007
  • This paper presents novel topologies implementation for Switched Reluctance Motor(SRM) drive used in commercial applications. For effective utilization of the developed system, a novel direct current controlled PWM scheme is designed and implemented to produce the desired dynamic speed characteristic. In comparison to conventional asymmetric converter topology, it can minimize entire system costs by reducing numbers of power semiconductors. Therefore, it may open up investigation of a new way for SRM to compete with other ac motors such as induction motors, brushless dc motors, etc. The validity of the proposed method is verified through theoretical explanation and experimental results.

5kW 급 주택용 고분자 연료전지 시스템 (Development of the 5kW Class Polymer Electrolyte Fuel Cell System for Residential Power Generation)

  • 양태현;박구곤;윤영기;이원용;윤왕래;김창수
    • 한국수소및신에너지학회논문집
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    • 제14권1호
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    • pp.35-45
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    • 2003
  • Polymer electrolyte fuel cells(PEFC) have been considered to be a suitable candidate for residential, portable and mobile applications, due to their high efficiency and power density, even at low operating temperature. KIER developed a 5kW class PEFC system for residential application and operated the system for over 1,000 hours. To develop a 5kW PEFC system, performance of a cell was improved through successive tests of single cell of small and large area. Fabrication of three 2,5 kW class stacks, design and fabrication of natural gas reformer, design of auxiliary equipments such as DC/DC converter, DC/AC inverter and humidifying units were carried out along with integration of components, operation and evaluation of total system. During the development period from 1999 to 2001, MEA(membrane electrode assembly) fabrication technologies, design and fabrication technologies for separators, stacking technologies and so on were developed, thereby providing basis for developing stacks of higher efficiency and power density in the future. Experience of development of natural gas reformer opened possibilities to use various kinds of fuels. Main results obtained from the development of a 5kW class PEFC system for residential application are summarized.

LED Driver with TRIAC Dimming Control by Variable Switched Capacitance for Power Regulation

  • Lee, Eun-Soo;Sohn, Yeung-Hoon;Nguyen, Duy Tan;Cheon, Jun-Pil;Rim, Chun-Taek
    • Journal of Power Electronics
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    • 제15권2호
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    • pp.555-566
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    • 2015
  • A TRIAC dimming LED driver that can control the brightness of LED arrays for a wide range of source voltage variations is proposed in this paper. Unlike conventional PWM LED drivers, the proposed LED driver adopts a TRIAC switch, which inherently guarantees zero current switching and has been proven to be quite reliable over its long lifetime. Unlike previous TRIAC type LED drivers, the proposed LED driver is composed of an LC input filter and a variable switched capacitance, which is modulated by the TRIAC turn-on timing. Thus, the LED power regulation and dimming control, which are done by a volume resistor in the same way as the conventional TRIAC dimmers, can be simultaneously performed by the TRIAC control circuit. Because the proposed LED driver has high efficiency and a long lifetime with a high power factor (PF) and low total harmonic distortion (THD) characteristics, it is quite adequate for industrial lighting applications such as streets, factories, parking garages, and emergency stairs. A simple step-down capacitive power supply circuit composed of passive components only is also proposed, which is quite useful for providing DC power from an AC source without a bulky and heavy transformer. A prototype 60 W LED driver was implemented by the proposed design procedure and verified by simulation and experimental results, where the efficiency, PF, and THD are 92%, 0.94, and 6.3%, respectively. The LED power variation is well mitigated to below ${\pm}2%$ for 190 V < $V_s$ < 250 V by using the proposed simple control circuit.