• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.167-174
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• 2015

This study describes how digital time delay deteriorates control performance in zero voltage switching (ZVS) phase-shifted full bridge (PSFB) converter. The small-signal model of the ZVS PSFB converter is derived from the buck-converter small-signal model. Digital time delay effects have been considered according to the digital sampling methods. The analysis verifies that digital time delays reduce the stability margin of the converter, and the double sampling technique exhibits better performance than the single sampling technique. Both simulation and experimental results based on 250 W ZVS PSFB confirm the validity of the analyses performed in the study.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.6
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• pp.598-609
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• 2005

Conventional phase shift full bridge (PSFB) converter has serious voltage oscillation problem across the secondary rectifier diodes, which would require the dissipate snubber circuit, thus degrades the overall efficiency. To overcome this problem a new simple voltage oscillation reduction technique (VORT) which effectively reduce the voltage oscillation of the secondary rectifier diodes for phase shift full bridge converter is proposed. Therefore, no dissipate snubber for rectifier diodes is needed. In addition, since it has wide zero voltage switching (ZVS) range, high efficiency can be achieved. Operational principle, analysis of voltage oscillation, and design consideration are presented compare with that of the conventional PSFB converter. To confirm the validity of the proposed VORT, experimental results from a 420W prototype are presented.

• 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.

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.443-452
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• 2002

A new phase shift full bridge (PSFB) converter with serially connected two transformers for telecommunication equipments of several hundred watts is proposed. The main features of the proposed converter are a wide input voltage range, an easiness to meet the requirement for zero voltage switching (ZVS) condition at a light load, and a small output voltage ripple. Furthermore, the serially connected two transformers can replace both a main transformer and an output inductor since the two transformers act as not only a main transformer but an output inductor by turns. Therefore, there is no need to use an output inductor, then the proposed converter features high power density. A mode analysis, design equations through a large signal modeling, and experimental results are presented to verify the validity of the proposed converter.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.286-288
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• 2005

Conventional phase shift full bridge (PSFB) converter has serious voltage oscillation problem across the secondary rectifier diodes, which would require the dissipate snubber circuit, thus degrades the overall efficiency. To overcome this problem, a new voltage oscillation reduction technique (VORT) which effectively reduce the voltage oscillation of the secondary rectifier diodes for phase shift 1011 bridge converter is proposed. Therefore, no dissipate snubber for rectifier diodes is needed. In addition, since it has wide zero voltage switching (ZVS) range, high efficiency can be achieved. Operational principle, analysis of voltage oscillation, and design consideration are presented compare with that of the conventional PSFB converter. To confirm the validity of the proposed VORT, experimental results from a 420W, 385Vdc/210Vdc prototype are presented.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.379-381
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• 2008

Generally additional leakage inductance and two clamp diodes are adopted into the conventional phase shift full bridge (PSFB) converter for reducing the voltage stress of secondary rectifier diodes and extending the range of zero voltage switching (ZVS) operation. However, since additional leakage inductance carries the ac current similar to the primary one, the core and copper loss oriented from additional leakage inductance can be high enough to decrease the whole efficiency of DC/DC converter. Therefore, in this paper, a new ZVS phase shift full bridge converter with separated primary winding (SPW) is proposed. Proposed converter makes the transformer and additional leakage inductor with one ferrite core. Using this method, leakage inductance is controlled by the winding ratio of separated primary winding. Moreover, by manufacturing the both magnetic components with one core, size and core loss can be reduced and it turns out the improvement of efficiency and power density of DC/DC converter. The operational principle of proposed converter is analyzed and verified by the 1.2kW prototype.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.3
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• pp.125-130
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• 2018

Arc lamps are now widely utilized as illumination sources for a large number of investigations in wide-field fluorescence microscopy. Among many power converters for the lamp, the PSFB (Phase-Shift Full-Bridge) converter with the ZVS (Zero Voltage Switching) is the most widely used soft switched circuit in high-power applications. Also, in the most luminaries, the power factor has to be more and more important. Thus, the power factor correction(PFC) must be included in the power system. A new igniter module using the switching power device and the transformer is proposed instead of the conventional igniter using the mechanical contactor. The proposed converter with the high power factor and high efficiency is verified through the experimental works.

• 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.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.370-373
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• 2002

A new phase shift full bridge converter(PSFB) with serially connected two transformers is proposed. It is well suited for applications in the communication equipment of a few hundred watts. The main features of the proposed converter are a wide input voltage range, an easiness to meet the requirement for zero voltage switching (ZVS) condition at a light load, and a small output voltage ripple. Furthermore, it features high power density since serially connected two transformers can replace both a main transformer and an output inductor. A mode analysis and experimental results are presented to verify the validity of the proposed converter.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.143-151
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• 2018

In this paper, a novel hybrid configuration combining a phase-shift full-bridge (PSFB) and a half-bridge resonant LLC converter is proposed for the On-Board Charger of Electric Vehicles (EVs). In the proposed converter, the PSFB converter shares the lagging-leg switches with half-bridge resonant converter to achieve the wide ZVS range for the switches and to improve the efficiency. The output voltage is modulated by the effective-duty-cycle of the PSFB converter. The proposed converter employs an active reset circuit composed of an active switch and a diode for the transformer which makes it possible to achieve zero circulating current and the soft switching characteristic of the primary switches and rectifier diodes regardless of the load, thereby making the converter highly efficient and eliminating the reverse recovery problem of the diodes. In addition an optimal power sharing strategy is proposed to meet the specification of the charger and to optimize the efficiency of the converter. The operation principle the proposed converter and design considerations for high efficiency are presented. A 6.6 kW prototype converter is fabricated and tested to evaluate its performance at different conditions. The peak efficiency achieved with the proposed converter is 97.7%.