• Title, Summary, Keyword: Phase shift transformer

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ZVS Operating Range Extension Method for High-Efficient High Frequency Linked ZVS-PWM DC-DC Power Converter

  • Sato S.;Moisseev S.;Nakaoka M.
    • Proceedings of the KIPE Conference
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    • pp.227-230
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    • 2003
  • In this paper, a full bridge edge-resonant zero voltage mode based soft-switching PWM DC-DC power converter with a high frequency center tapped transformer link stage is presented from a practical point of view. The power MOSFETS operating as synchronous rectifier devices are implemented in the rectifier center tapped stage to reduce conduction power losses and also to extend the transformer primary side power MOSFETS ZVS commutation area from the rated to zero-load without a requirement of a magnetizing current. The steady-state operation of this phase-shift PWM controlled power converter is described in comparison with a conventional ZVS phase-shift PWM DC-DC converter using the diodes rectifier. Moreover, the experimental results of the switching power losses analysis are evaluated and discussed in this paper. The practical effectiveness of the ZVS phase-shift PWM DC-DC power converter treated here is actually proved by using 2.5kW-32kHz breadboard circuit. An actual efficiency of this converter is estimated in experiment and is achieved as 97$\%$ at maximum.

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Identification of Inrush and Internal Fault in Indirect Symmetrical Phase Shift Transformer Using Wavelet Transform

  • Bhasker, Shailendra Kumar;Tripathy, Manoj;Kumar, Vishal
    • Journal of Electrical Engineering and Technology
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    • v.12 no.5
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    • pp.1697-1708
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    • 2017
  • This paper proposes an algorithm for the differential protection of an Indirect Symmetrical Phase Shift Transformer (ISPST) by considering the different behaviors of the compensated differential current under internal fault and magnetizing inrush conditions. In this algorithm, a criterion function is defined which is based on the difference of amplitude of the wavelet transformation over a specific frequency band. The function has been used for the discrimination between three phase magnetizing inrush and internal fault condition and requires less than a quarter cycle after disturbance. This method is independent of any coefficient or threshold values of wavelet transformation. The merit of this algorithm is demonstrated by the simulation of different faults in series and excitation unit and magnetizing inrush with varying switching conditions on ISPST using PSCAD/EMTDC. Due to unavailability of in-field large interconnected transformers for such a large number of destructive tests, the results are further verified by Real Time Digital Simulator (RSCAD/RTDS). The proposed algorithm has been compared with the conventional harmonic restraint based method that justifies the application of wavelet transform for differential protection of ISPST. The proposed algorithm has also been verified for different rating of ISPSTs and satisfactory results were obtained.

Calculation of Leakage Inductance of Integrated Magnetic Transformer with Separated Secondary Winding Used in ZVS PSFB Converter

  • Tian, Jiashen;Zhang, Yiming;Ren, Xiguo;Wang, Xuhong;Tao, Haijun
    • Journal of Magnetics
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    • v.21 no.4
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    • pp.644-651
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    • 2016
  • A novel zero voltage switching (ZVS) phase shift full bridge (PSFB) converter used in geophysical exploration is proposed in this paper. To extend the ZVS ranges and increase power density of the converter, external inductor acting as leakage inductance is applied and integrated into the integrated magnetic (IM) transformer with separated secondary winding. Moreover, the loss of ZVS PSFB converter is also decreased. Besides, the analysis and accurate prediction methodology of the leakage inductance of the IM transformer are proposed, which are based on magnetic energy and Lebedev. Finally, to verify the accuracy of analysis and methodology, the experimental and finite element analysis (FEA) results of IM transformer and 40 kW converter prototypes are given.

An Isolated Bidirectional Modular Multilevel DC/DC Converter for Power Electronic Transformer Applications

  • Wang, Zhaohui;Zhang, Junming;Sheng, Kuang
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.861-871
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    • 2016
  • With high penetration of renewable energies, power electronic transformers (PETs) will be one of the most important infrastructures in the future power delivery and management system. In this study, an isolated bidirectional modular multilevel DC/DC converter is proposed for PET applications. A modular multilevel structure is adopted as switching valves to sustain medium voltages to achieve modular design and high reliability. Only one high-frequency transformer is used in the proposed converter, which significantly simplifies the circuit and galvanic insulation design. A dual-phase-shift modulation strategy is proposed to regulate the output power and achieve a simple voltage balancing control. A down-scaled (2 kW/20 kHz) prototype is constructed to demonstrate the proposed converter and verify the control strategy. The experimental results comply with the theoretical analysis well, with the highest power efficiency reaching 97.6%.

Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter

  • Li, Xin-Lan;Shin, Yong-Hwan;Won, Jae-Sun;Kim, Jong-Sun;Shin, Hwi-Beom
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.2
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    • pp.119-126
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    • 2010
  • An integrated magnetic (IM) transformer is proposed for a phase shifted full bridge (PSFB) converter with zero voltage switching (ZVS). In a proposed IM transformer, the transformer is located on the center leg of E-core and the output inductor is wound on two outer legs with air gap. The proposed IM transformer is analyzed by using the magnetic capacitor model. For reducing the core size, EE core is redesigned. The proposed IM transformer is experimentally verified on a 1.2 kW prototype converter. The converter efficiency with the proposed IM transformer is about 93 % at full load and its volume size can be reduced. It can be expected that the power density can be largely increased with the proposed IM transformer.

A Study on the ZVZCS Interleaving Two-Transistor Forward Converter using Phase Shift Control (위상이동 방식을 적용한 ZVZCS Interleaving Two-Transistor Forward 컨버터에 관한 연구)

  • Han, Kyung-Tae;Kim, Yong;Bae, Jin-Yong;Lee, Kyu-Hoon;Cho, Kyu-Man
    • Proceedings of the KIEE Conference
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    • pp.276-280
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    • 2003
  • This paper presents a zero voltage and zero current switching (ZVZCS) interleaving two-transistor forward converter for high input voltage and high power application. A phase shift has a disadvantage that a circulating current and RMS current stress, conduction losses of transformer and switching devices increases. Due to this circulating current and RMS current stress, conduction losses of transformer and switching devices increases. To alleviate these problems, we propose an improved interleaving two-transistor forward Zero Voltage and Zero Current Switching (ZVZCS) dc/dc converter using a tapped inductor a snubber capacitor and two snubber diodes attached at the secondary side of transformer. The proposed ZVZCS converter is verified on a 1.8kW, 5kHz experimental prototype.

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Design and Analysis of a 7kW LDC using Coupled Inductor for Heavy Hydrogen Electric Transport Vehicle (Coupled Inductor를 사용한 대형수소전기화물차용 7kW급 저전압 컨버터의 설계 및 분석)

  • Heo, Gyeong-Hyeon;Lee, Woo-Seok;Choi, Seung-Won;Lee, Il-Oun;Song, Hyung-Suk;Lee, Jun-Young
    • The Transactions of the Korean Institute of Power Electronics
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    • v.25 no.1
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    • pp.37-43
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    • 2020
  • This study proposes a 7kW low-voltage DC-DC converter (LDC) using a coupled inductor (CI) for heavy hydrogen electric transport vehicles. The LDC uses a phase-shift manner for soft switching. SiC-MOSFET is used to reduce the loss of reverse recovery current through the use of a high switching frequency. LDC is require large transformer and inductor because of large output current. The size of transformer and inductor can be reduced by deviding the transformer and inductor into two pieces each. This work presents the experimental results of the proposed circuit.

Phase Shift Analysis and Phase Identification for Distribution System with 3-Phase Unbalanced Constant Current Loads

  • Byun, Hee-Jung;Shon, Sugoog
    • Journal of Electrical Engineering and Technology
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    • v.8 no.4
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    • pp.729-736
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    • 2013
  • Power grids are large complicated networks in use around. An absolute phase value for a particular unknown-phase line at a local site should be identified for the operation and management of a 3-phase distribution network. The phase shift for a specific point in the line, as compared with a phase reference point at a substation, must be within a range of ${\pm}60^{\circ}$ for correct identification. However, the phase shift at a particular point can fluctuate depending on the line constants, transformer wiring method, line length, and line amperage, etc. Conducted in this study is a theoretical formulation for the determination of phase at a specific point in the line, Simulink modeling, and analysis for a distribution network. In particular, through evaluating the effects of unbalanced current loads, the limitations of the present phase identification methods are described.

Design and Control of the Phase Shift Full Bridge Converter for the On-board Battery Charger of Electric Forklifts

  • Kim, Tae-Hoon;Lee, Seung-Jun;Choi, Woo-Jin
    • Journal of Power Electronics
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    • v.12 no.1
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    • pp.113-119
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    • 2012
  • This paper describes the design and control of a phase shift full bridge converter with a current doubler, which can be used for the on-board charger for the lead-acid battery of electric forklifts. Unlike the common resistance load, the battery has a large capacitance element and it absorbs the entire converter output ripple current, thereby shortening the battery life and degrading the system efficiency. In this paper a phase shift full bridge converter with a current doubler has been adopted to decrease the output ripple current and the transformer rating of the charger. The charge controller is designed by using the small signal model of the converter, taking into consideration the internal impedance of the battery. The stability and performance of the battery charger is then verified by constant current (CC) and constant voltage (CV) charge experiments using a lead-acid battery bank for an electric forklift.

Design of Integrated Magnetic Transformer for ZVS Phase Shift Full Bridge Converter

  • Li, Xin-Lan;Jang, Eun-Sung;Shin, Yong-Whan;Won, Jae-Sun;Kim, Jong-Sun;Oh, Dong-Seong;Shin, Hwi-Beom
    • Proceedings of the KIPE Conference
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    • pp.40-42
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    • 2008
  • This integrated magnetic (IM) transformer is proposed for a phase shifted full bridge (PSFB) converter with zero voltage switching (ZVS). In a new IM transformer, the transformer is located on the center leg of E-core and the output inductor is wound on two outer legs. The proposed circuit is analyzed electrically and magnetically. An E-core is redesigned and implemented. The proposed IM transformer is experimentally compared with the conventional one through a 1.2kW prototype converter.

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