• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.5
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• pp.501-506
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• 2013

A hold-up time compensation circuit is proposed to get high efficiency of the front-end phase-shifted full bridge DC/DC converter. The proposed circuit can make the phase-shifted full bridge front-end DC/DC converter built with 0.5 duty ratio so that the conduction loss of the primary side and voltage stress across rectifier in the secondary side are reduced and the higher efficiency can be obtained. Furthermore, the requirement of an output filter significantly can diminish due to the perfect filtered waveform. A 12V/100A prototype has been made and experimental results are given to verify the theoretic analysis and detailed features.

• Journal of Power Electronics
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• v.8 no.3
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• pp.201-209
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• 2008

This paper presents the modeling and design of a digital controller for a phase-shifted full-bridge converter (PSFBC) in a discrete-time domain. The discretized PSFBC model is first derived and then analyzed considering the sampling effect and the system parameters. Based on this model, the digital controller is directly designed in a discrete-time domain. The simulation and experimental results are provided to show the validity of the proposed modeling and controller design.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.5
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• pp.372-375
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• 2021

A three-leg inverter-type isolated DC-DC Converter that can use 220 and 440 V grid input voltages is introduced. The secondary circuit structure of the proposed topology is center-tap, which is the same as the conventional phase-shifted full-bridge converter. However, the primary circuit structure is composed of a three-leg inverter structure and a transformer, in which two primary windings are connected in series. The proposed circuit structure has a wider input voltage range than the conventional phase-shifted full-bridge converter, and the circulating-current on the primary-side is reduced. In addition, the voltage stress at the secondary rectifier is greatly improved, and high efficiency can be achieved at a high input voltage by removing the snubber circuit added to the conventional converter. Prototype converters with input DC of 311 V, output of 622 V, and 50 V and 6 kW class specifications were designed and manufactured to verify the validity of the proposed topology; the experimental results are presented.

• Journal of Power Electronics
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• v.17 no.1
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• pp.31-40
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• 2017

A novel voltage-fed single-stage power factor correction (PFC) full-bridge converter based on asymmetric phase-shifted control for battery chargers is proposed in this paper. The attractive feature of the proposed converter is that it can operate in a wide output voltage range without an output low-frequency ripple, which is indispensable in battery charger applications. Meanwhile, the converter can maintain a high power factor and a controllable dc bus voltage over a wide output voltage range. In this paper, the realization of PFC and the operation principle of asymmetric phase-shifted control are given. A small-signal analysis of the proposed single-stage power factor correction (PFC) full-bridge converter is performed. Experimental results obtained from a 1kW experimental prototype are given to validate the feasibility of the proposed converter. The PF is higher than 0.97 over the entire output voltage range with the proposed control strategy.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.6
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• pp.558-565
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• 2015

Gallium nitride high-electron mobility transistor (GaN HEMT) is the strongest candidate for replacing Si MOSFET. Comparing the figure of merit (FOM) of GaN with the state-of-the-art super junction Si MOSFET, the FOM is much better because of the wide band gap characteristics and the heterojunction structure. Although GaN HEMT has many benefits for the power conversion system, the performance of the power conversion system with the GaN HEMT is sensitive because of its low threshold voltage ($V_{th}$) and even lower parasitic capacitance. This study examines the characteristics of a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT. The problem of unoptimized dead time is analyzed on the basis of the output capacitance of GaN HEMT. In addition, the printed circuit board (PCB) layout consideration is analyzed to reduce the negative effects of parasitic inductance. A comparison of the experimental results is provided to validate the dead time and PCB layout analysis for a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.237-240
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• 2021

This research proposes a new rectifier circuit to reduce the circulating current of a phase-shifted full bridge converter. The proposed circuit is a structure in which the output inductor of the secondary rectifier circuit is changed to a coupled inductor in the phase-shifted full bridge with the existing center-tapped rectifier. The parts are rearranged after adding a diode. After applying the proposed circuit, the circulating current to the primary current of the transformer and the voltage stress of the rectifier diode on the secondary side of the transformer are reduced. Accordingly, the snubber loss of the rectifier is improved. By reducing the circulating current and snubber loss, the circuit achieves higher efficiency than conventional circuits. In this research, we present the structure of the proposed circuit, its strengths, and the analysis results from experiments. Furthermore, its effectiveness is verified through the experimental results of a prototype converter with an input of 300-400 V and an output of 50 V/1 kW.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.22-24
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• 2006

Of all the proposed resonant techniques, the well-known phase-shifted full bridge converter remains one of the most attractive because it offers an easy way of achieving ZVS with a minimum of extra components added, which is essential for the high power applications. This paper describes the design of a digital controller for a Phase Shifted Full-bridge PWM Converter. The small-signal model is derived incorporating the effects of phase-shift control and the utilization of the transformer leakage inductance and power FET junction capacitances to achieve the zero-voltage resonant switching. Based on the derived small-signal model, the digital controller is designed in the discrete domain. The performance of designed controller is verified through the simulation.

• Journal of Power Electronics
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• v.18 no.4
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• pp.975-984
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• 2018

This work presents a high efficiency phase shifted full bridge (PSFB) DC-DC converter for use in the second stage of a battery charger for neighborhood electrical vehicle (EV) applications. In the design of the converter, Lithium-ion battery cells are preferred due to their high voltage and current rates, which provide a high power density. This requires wide range output voltage regulation for PSFB converter operation. In addition, the battery charger works with a light load when the battery charge voltage reaches its maximum value. The soft switching of the PSFB converter depends on the dead time optimization and load condition. As a result, the converter has to work with soft switching at a wide range output voltage and under light conditions to reach high efficiency. The operation principles of the PSFB converter for the continuous current mode (CCM) and the discontinuous current mode (DCM) are defined. The performance of the PSFB converter is analyzed in detail based on wide range output voltage and load conditions in terms of high efficiency. In order to validate performance analysis, a prototype is built with 42-54 V / 15 A output values at a 200 kHz switching frequency. The measured maximum efficiency values are obtained as 94.4% and 76.6% at full and at 2% load conditions, respectively.

• The Transactions of the Korean Institute of Power Electronics
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• v.6 no.3
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• pp.265-272
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• 2001

The traditional 60[Hz] power supply for during magnetron in microwave oven has disadvantages of heavy weight and low efficiency due to 60[Hz] High Voltage Transformer(HVT), capacitor and th phase control of thyristors. To alleviate these disadvantages, this paper proposes a 20[kHz] phase-shifted Full-Bridge(FB) Zero-Voltage-Switched(ZVS) PWM converter for driving a 600[W] magnetron in an 1[kW] microwave oven. The proposed converter has advantages of light weight and high power density.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.6
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• pp.425-432
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• 2020

The phase-shifted, full-bridge (PSFB) DC-DC converter is widely used in electric vehicles (EVs) to charge a low-voltage (12 V) battery from a high-voltage battery. A Photovoltaic (PV) module-integrated PSFB converter is proposed for the EV power conversion system. The converter is useful because solar energy can be utilized to extend the driving range. The buck converter circuit is simply realized by adding one switch to the conventional PSFB converter's secondary side. For the inductor and diode, the existing components in the PSFB converter are shared. The proposed converter can charge a low-voltage battery from the PV module with maximum power point tracking. In addition, the two power sources can be used simultaneously, and efficiency is increased by reducing the circulating current, which is a problem for the conventional PSFB converter.