• Journal of Power Electronics
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• 제10권6호
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• pp.673-679
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• 2010

Input-series-output-parallel (ISOP) connected DC-DC converters enable low voltage rating switches to be used in high voltage input applications. In this paper, a DSP is adopted to generate digital phase-shifted PWM signals and to fulfill the closed-loop control function for ISOP connected two full-bridge DC-DC converters. Moreover, a stable output current sharing control strategy is proposed for the system, with which equal sharing of the input voltage and the load current can be achieved without any input voltage control loops. Based on small signal analysis with the state space average method, a loop gain design with the proposed scheme is made. Compared with the conventional IVS scheme, the proposed strategy leads to simplification of the output voltage regulator design and better static and dynamic responses. The effectiveness of the proposed control strategy is verified by the simulation and experimental results of an ISOP system made up of two full-bridge DC-DC converters.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.197-198
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• 2014

본 논문에서는 Si MOSFET을 차세대 반도체인 GaN FET(Gallium Nitride Field Effect Transistor)으로의 대체 할 시 발생하는 문제점을 분석한다. 다양한 전력변환 시스템에 적용 가능한 위상 천이 풀브리지(Phase Shifted Full Bridge) DC-DC 컨버터를 대상으로 각각 Si MOSFET 및 GaN FET를 적용하고 실험을 통해 문제점을 확인 및 분석한다.

• Journal of Power Electronics
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• 제16권3호
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• pp.823-831
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• 2016

A high-efficiency method is proposed to suppress magnetic core imbalance in phase-shifted full-bridge (PSFB) converters. Compared with conventional solutions, such as controlling peak current mode (PCM) or adding DC blocking capacitance, the proposed method has several advantages, such as lower power loss and smaller size, because the additional current sensor or blocking capacitor is removed. A time domain model of the secondary side is built to analyze the relationship between transformer core imbalance and cathode voltage of secondary side rectifiers. An approximate control algorithm is designed to achieve asymmetric phase control, which reduces the effects of imbalance. A 60 V/15 A prototype is built to verify the proposed method. Experimental results show that the numerical difference of primary side peak currents between two adjacent cycles is suppressed from 2 A to approximately 0 A. Meanwhile, compared with the PCM solution, the efficiency of the PSFB converter is slightly improved from 93% to 93.2%.

• 전력전자학회논문지
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• 제27권6호
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• pp.526-534
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• 2022

The modular multilevel converter (MMC) has been widely applied to various industrial areas because of its various advantages and structural characteristics. Therefore, many methods for synthesizing the output voltage of MMC have been studied. Among these methods, phase-shifted pulse width modulation (PSPWM) is frequently used in MMC systems because it has diverse merits, such as excellent output qualities even with a small number of cells and uniform power distribution among cells. In this study, the total harmonic distortion (THD) of the output voltage is analyzed in accordance with the number of cells in one arm of a single-delta bridge cell MMC in order to compare PSPWM methods in terms of the THD of the output voltage. The physical characteristics of the triangle and sawtooth carrier waves used for the PSPWM and the mathematical modeling of output voltage are introduced. Then, the obtained results are verified through real-time simulation of a 1 MW single-delta bridge cell MMC system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.140-145
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• 2001

This paper proposes to use a 20[kHz] phase­shifted Full-Bridge (FB) Zero-Voltage-Switched (ZVS) PWM converter in order to drive a 600[W] magnetron, and analyzes the operational modes in a switching period. Additionally, the controller of the average anode current is designed. Simulation studies and experiments verify that the proposed converter and the average anode current controller shows good performance to drive the magnetron.

• 전기학회논문지
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• 제65권1호
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• pp.88-96
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• 2016

In this paper, the GaN FET based phase-shift full-bridge dc-dc converter design is implemented. Switch characteristics of GaN FET were analyzed in detail by comparing state-of-the-art Si MOSFET. Owing to the low conduction resistance and parasitic capacitance, it is expected to GaN FET based power conversion system has improved performance. However, GaN FET is vulnerable to electric interference due to the relatively low threshold voltage and fast switching transient. Therefore, it is necessary to consider PCB layout to design GaN FET based power system because PCB layout is the main reason of stray inductance. To reduce the electric noise, gate voltage of GaN FET is analyzed according to operation mode of phase-shift full-bridge dc-dc converter. Two 600W phase-shifted full-bridge dc-dc converter are designed based on the result to evaluate effects of stray inductance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 춘계전력전자학술대회 논문집(1)
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• pp.231-234
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• 2003

This paper presents a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control scheme DC-DC power converter, which can be used as power conditioner fur small-scale fuel cell power generation system. Using full-bridge soft-switching DC-DC converter topology makes possible to use low voltage high performance MOSFETs to achieve high efficiency of the power conditioner. A tapped inductor filter is implemented in the proposed soft-switching converter topology to achieve soft-switching PWM constant high frequency operation for a wide load variation range. to minimize circulating and idling currents without using additional resonant circuit and auxiliary power switching devices. The practical effectiveness of the proposed soft-switching DC-DC converter is verified in laboratory level experiment with 1 kW 100kHz breadboard setup using power MOSFETs. Actual efficiency of 94-96$\%$ is obtained for the wide load range

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2000년도 학술대회논문집
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• pp.188-192
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• 2000

This paper presents a novel prototype of soft-switching PWM Full-bridge converter which incorporates active power switches in series with each rectifier diode in transformer secondary side. Switching and conduction losses of all the switches and devices are reduced as well as commutating current and circulating current flowing through transformer as compared with conventional converter. And duty ratio of primary switches is constant for maximum voltage conversion ratio. But this converter can be varied output by duty ratio of secondary switches. Operation principles basically the same as that of the PWM Full-bridge converter published previously. The operating characteristics of this converter are illustrate and discussed including the simulated analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.388-391
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• 1996

The conventional high frequency phase-shifted full bridge DC-DC converter has a disadavantage that a circulating current flows through transformer and switching devices during the freewheeling interval Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate this problem, this study provides a novel circulating current free type high frequency soft switching phase-shifted full bridge DC-DC converter which applies the energy recovery snubber(ERS) attached at the secondary side of transformer. The ERS adopted in this study is consisted of three fast recovery diode($Ds_1$, $Ds_2$, $Ds_3$), two resonant capacitor($Cs_1$, $Cs_2$) and a small resonant inductor [(Lr) : It can be ignored because the transformer leakage inductance(Ll) is able to use in stead of inserting the resonant inductor(Lr)]

• 전력전자학회논문지
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• 제26권2호
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• pp.112-119
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• 2021

This study proposes a design method of high-power-density and high-efficiency low-voltage DC-DC converters using SiC MOSFET and the optimized planar transformer design procedure based on the figure-of-merit. The secondary rectifying circuit of the phase-shifted full-bridge converter is compared to achieve high power density and high efficiency, and the phase-shifted full bridge converter with a current-doubler rectifier is selected. The planar transformer is designed by the proposed optimized design procedure and verified by FEA simulation. To validate the proposed design method, experimental results from a 3 kW prototype are provided. The prototype achieved 95.28% maximum efficiency and a power density of 2.98 kW/L.