• Title/Summary/Keyword: New correction factor

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FE modeling for geometrically nonlinear analysis of laminated plates using a new plate theory

  • Bhaskar, Dhiraj P.;Thakur, Ajaykumar G.
    • Advances in aircraft and spacecraft science
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    • v.6 no.5
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    • pp.409-426
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    • 2019
  • The aim of the present work is to study the nonlinear behavior of the laminated composite plates under transverse sinusoidal loading using a new inverse trigonometric shear deformation theory, where geometric nonlinearity in the Von-Karman sense is taken into account. In the present theory, in-plane displacements use an inverse trigonometric shape function to account the effect of transverse shear deformation. The theory satisfies the traction free boundary conditions and violates the need of shear correction factor. The governing equations of equilibrium and boundary conditions associated with present theory are obtained by using the principle of minimum potential energy. These governing equations are solved by eight nodded serendipity element having five degree of freedom per node. A square laminated composite plate is considered for the geometrically linear and nonlinear formulation. The numerical results are obtained for central deflections, in-plane stresses and transverse shear stresses. Finite element Codes are developed using MATLAB. The present results are compared with previously published results. It is concluded that the geometrically linear and nonlinear response of laminated composite plates predicted by using the present inverse trigonometric shape function is in excellent agreement with previously published results.

A New Modular 3-phase AC-DC Flyback Converter for Telecommunication (새로운 통신전원용 3상 AC-DC Flyback 컨버터)

  • Lee, Jong-Pil;Choi, Ju-Yeop;Song, Joong-Ho;Choy, Ick;Kim, Taek-Yong;Yoon, Tae-Woong
    • The Transactions of the Korean Institute of Power Electronics
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    • v.4 no.2
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    • pp.159-165
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    • 1999
  • Three-phase AC-DC flyback converter with high power factor correction and tight regulation is presented in this p paper. The advantage of the proposed converter does not require expensive high voltage and high cun‘ent devices that a are normally needed in popular boost type 3-phase converter. In this paper the detailed small signal analysis of the m modular 3-phase AC-DC flyback converter is provided for control purposes and also experimental results are included t to confirm the validity of the analysis.

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A New Control Scheme of the Line-Interactive UPS Using the Series Active Compensator (직렬 능동 보상기를 이용한 Line-Interactive UPS의 새로운 제어 기법)

  • Jang, Hoon;Lee, Woo-Cheol;Hyun, Dong-Seok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.52 no.8
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    • pp.405-412
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    • 2003
  • This paper presents a three-phase Line-Interactive uninterruptible power supply (UPS) system with series-parallel active power-line conditioning capabilities, using synchronous reference frame (SRF) based controller, which allows an effective power factor correction, source harmonic voltage compensation, load harmonic current suppression, and output voltage regulation. The three-phase UPS system consists of two active power compensator topologies. One is a series active compensator, which works as a voltage source in phase with the source voltage to have the sinusoidal source current and high power factor under the deviation and distortion of the source voltage. The other is a parallel active compensator which works as a conventional sinusoidal voltage source in phase with the source voltage, providing to the load a regulated and sinusoidal voltage with low THD (total harmonic distortion). The control algorithm using SRF method and the active power flow through the Line-interactive UPS systems are described and studied. The simulation and experimental results are depicted in this paper to show the effect of the proposed algorithm.

Improved Power Quality IHQRR-BIFRED Converter Fed BLDC Motor Drive

  • Singh, Bhim;Bist, Vashist
    • Journal of Power Electronics
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    • v.13 no.2
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    • pp.256-263
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    • 2013
  • This paper presents an IHQRR (Integrated High Quality Rectifier Regulator) BIFRED (Boost Integrated Flyback Rectifier Energy Storage DC-DC) converter fed BLDC (Brushless DC) motor drive. A reduced sensor topology is derived by utilizing a BIFRED converter to operate in a dual DCM (Discontinuous Conduction Mode) thus utilizing a voltage follower approach for the PFC (Power Factor Correction) and voltage control. A new approach for speed control is proposed using a single voltage sensor. The speed of the BLDC motor drive is controlled by varying the DC link voltage of the front end converter. Moreover, fundamental frequency switching of the VSI's (Voltage Source Inverter) switches is used for the electronic commutation of the BLDC motor which reduces the switching losses in the VSI. The proposed drive is designed for a wide range of speed control with an improved power quality at the AC mains which falls within the recommended limits imposed by international power quality standards such as IEC 61000-3-2.

Phase-shedding in Boundary Conduction Mode Converter with Optimal Transition Load-level

  • Choi, Wooin;Baek, Jong-Bok;Cho, Bo-Hyung
    • Proceedings of the KIPE Conference
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    • 2011.11a
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    • pp.73-74
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    • 2011
  • Phase-shedding, one famous technology for multi-phase converters, is implemented in a bi-directional multi-phase converter for ESS. It reduces active operating modules at light load to compensate efficiency. Shedding point, the load level where the converter changes the number of active modules, is important factor that affects the effect of phase-shedding. Loss analysis is done for determining shedding point. Phase-shedding hysteresis is applied so that excessive phase transition is avoided. This paper proposes shedding point correction where the shedding point is adaptively corrected by calculating a new shedding point.

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A Unity Power Factor Electronic Ballast for Fluorescent Lamp having Improved Valley Fill and Valley Boost Converter (개선된 밸리필과 밸리용 승압형 변환기를 결합한 고역률 형광등용 전자식 안정기)

  • Youn, Yong-Sik;Chae, Gyun;Cho, Gyun-Hyeong
    • Proceedings of the KIEE Conference
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    • 1997.07f
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    • pp.2002-2006
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    • 1997
  • A new PF correction topology, Improved Valley Fill (IVF) with Valley Boost Converter (VBC) used in the electronic ballast for fluorescent lamp is presented. The IVF can adjust the valley voltage higher than half the peak line voltage. Hence, there is no pulsating line current around the line voltage peak, PF and THD are significantly improved. The VBC is added to the IVF to achieve unity PF and to increase the valley voltage. The measured PF and THD for a prototype electronic ballast are 0.997 and 5%, respectively, and the lamp current CF is as low as 1.5

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Novel Two Stage AC-to-DC Converter with Single Switched Zero Voltage Transition Boost Pre-Regulator using DC-Linked Energy Feedback (새로운 영전압 스위칭 이단방식의 고역률 컨버터)

  • Roh, Chung-Wook;Moon, Gun-Woo;Jung, Young-Seok;Youn, Myung-Joong
    • Proceedings of the KIEE Conference
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    • 1996.07a
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    • pp.385-387
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    • 1996
  • A novel two stage soft-switching ac-to-dc convener with power factor correction is proposed. The proposed convener provides zero-voltage-switching (ZVS) condition to main switch of boost pre-regulator without auxiliary switch. Comparing to the conventional two stage approach(ZVS-PWM boost rectifier followed by off-line ZVS dc-dc step down converter), the proposed approach is simple and reducing EMI noise problem. A new simple DC-linked energy feedback circuit provides zero-voltage-switching condition to boost pre-regulator without imposing additional voltage and current stresses and loss of PWM capability. Operational principle, analysis, control of the proposed converter together with the simulation results of 1KW prototype are presented.

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Low Loss Soft Switching Boost Converter (저 손실형 소프트 스위칭 승압형 컨버터)

  • Park, So-Ri;Jang, Su-Jin;Won, Chung-Yuen;Jung, Yong-Chae
    • Proceedings of the KIPE Conference
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    • 2007.11a
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    • pp.34-36
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    • 2007
  • A new soft switching boost converter is proposed in this paper. The conventional boost converter generates switching losses at turn on and off. Because of that, the whole system efficiency is reduced. The proposed converter utilizes soft switching method using an auxiliary switch and resonant circuit. Thus, the converter reduces switching losses lower than ones of hard switching method. The proposed soft switching boost converter can be applied to photovoltaic system, power factor correction circuit and so on.

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A New Frequency Controlled Half-bridge Converter with Hold-up Time Extension Circuit

  • Kim, Duk-You;Kim, Jae-Kuk;Lee, Woo-Jin;Moon, Gun-Woo
    • Proceedings of the KIPE Conference
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    • 2008.06a
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    • pp.382-384
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    • 2008
  • Hold-up time is a special requirement for the front end DC/DC converter in a server power supply. It forces the converter with the variable switching frequency to operate in a wide switching frequency range, which makes the regulation difficult and reduces the power density. In this paper a novel frequency controlled half bridge converter with the hold-up time extension circuit is proposed. During the hold-up time, the auxiliary switches are turned on, thus the resonant inductance is reduced and the voltage conversion ratio is increased. Therefore, the output capacitor of the power factor correction (PFC) circuit can be decreased, and the converter can have high power density. The proposed converter is verified by experimental results from a prototype with 700W, 400V input, and 12V output.

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Module Type Parallel Driving Algorithm for High Voltage Direct-Current source (고전압 소스를 위한 모듈식 병렬운전 알고리즘)

  • Woo, Byung-Guk;Lee, Yong-Hwa;Kang, Chan-Ho;Cho, Kwan-Yuhl
    • Proceedings of the KIPE Conference
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    • 2008.06a
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    • pp.24-27
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    • 2008
  • For high voltage DC-DC converters, the parallel operation of several high voltage source modules is necessary to reduce the material cost. In the conventional parallel operation with HDC module control unit, it is difficult to repair the HDC system for the failure of control unit. To overcome these problems, new parallel operating algorithm for high voltage DC-DC converter is presented. The proposed algorithm has no main control unit and each module can be selected as the master according to the operating conditions. Therefore, one of modules can be replaced as the master immediately when the previous master module is failed. In addition, the extension of extra modules can be simple.

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