• Journal of Power Electronics
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• v.16 no.1
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• pp.93-101
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• 2016

A new four-primary-switch diode clamped soft switching three-level DC-DC converter (TLDC) with full zero-voltage switching (ZVS) load range and TL secondary voltage waveform is proposed. The operation principle and characteristics of the presented converter are discussed, and experimental results are consistent with theoretical predictions. The improvements of the proposed converter include a simple and compact primary structure, TL secondary rectified voltage waveform, wide load range ZVS for all primary switches, and full output-regulated range with soft switching operation. The proposed converter also has some disadvantages. The VA rating of the transformer is slightly larger than that of conventional TLDCs in variable input and constant output mode. The conduction loss of the primary coil is slightly higher because an air gap is inserted into the magnetic cores of the transformer. Finally, the secondary circuit is slightly complex.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.518-519
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• 2012

This paper suggested a fuel cell generation system which combined interleaved full-bridge converter with half-bridge inverter. High ratio step-up converter is essential to use the power as general voltage source. Full-bridge converter has high efficiency and can boost the input voltage to high output with transformer. With series connected capacitors, interleaved full-bridge converter and half-bridge inverter are combined. Half-bridge inverter has two fewer switches compared to full-bridge type. Also, switching loss can be reduced. The performance is verified through simulation with 1.5[kW] fuel cell generation system.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.45-48
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• 2000

By the use of he DSP and microprocessor controller many high power converter such as especially inverter and motor drive system may be enhanced resulting in the improved robustness of EMI the ability to communicate the operating conditions and the ease of adjusting the control parameters. However the digital controller using DSP or microprocessor has not been applied in the high frequency switching power supplies especially in full bridge dc/dc converters. this paper presents a promising solution to the dc bias control problem of high frequency transformer in high power full bridge converter.

• Journal of Power Electronics
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• v.7 no.3
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• pp.181-190
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• 2007

This paper presents a novel circuit topology of a DC bus line series switch and parallel snubbing capacitor-assisted soft-switching PWM full-bridge inverter type DC-DC power converter with a high frequency planar transformer link, which is newly developed for high performance arc welding machines in industry. The proposed DC-DC power converter circuit is based upon a voltage source-fed H type full-bridge soft-switching PWM inverter with a high frequency transformer. This DC-DC power converter has a single power semiconductor switching device in series with an input DC low side rail and loss less snubbing capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge arms and DC bus line can achieve ZCS turn-on and ZVS turn-off transition commutation. Consequently, the total switching power losses occurred at turn-off switching transition of these power semiconductor devices; IGBTs can be reduced even in higher switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules can be realized at 60 kHz. It is proved experimentally by power loss analysis that the more the switching frequency increases, the more the proposed DC-DC power converter can achieve a higher control response performance and size miniaturization. The practical and inherent effectiveness of the new DC-DC converter topology proposed here is actually confirmed for low voltage and large current DC-DC power supplies (32V, 300A) for TIG arc welding applications in industry.

• 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.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.8
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• pp.1055-1063
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• 2014

Power losses of a 1-stage DC-DC converter and 2-stage DC-DC converter are compared in this paper. A phase-shift full-bridge DC-DC converter is considered as 1-stage topology. This topology has disadvantages in the stress of rectifier diodes because of the resonance between the leakage inductor of the transformer and the junction capacitor of the rectifier diode. 2-stage topology is composed of an LLC resonant full-bridge DC-DC converter and buck converter. The LLC resonant full-bridge DC-DC converter does not need an RC snubber circuit of the rectifier diode. However, there is the drawback that the switching loss of the buck converter is large due to the hard switching operation. To reduce the switching loss of the buck converter, SiC MOSFET is used. This paper analyzes and compares power losses of two topologies considering temperature condition. The validity of the power loss analysis and calculation is verified by a PSIM simulation model.

• Journal of Power Electronics
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• v.15 no.1
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• pp.1-9
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• 2015

This study presents a novel transformer isolated parallel connected quasi Z-source (qZ-source) full-bridge DC-DC converter that uses a coupled inductor in both the qZ-source network and output filter inductor. Unlike traditional voltage-fed or current-fed converters, the proposed converter can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost functions can be achieved and converter reliability can be significantly improved. All the bulky inductors in the qZ-source network and output filter can also be minimized with the proposed inductor structures. A 4 kW prototype DC-DC converter is built and tested to verify the performance of the proposed converter.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.366-373
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• 2005

This paper presents two new circuit topologies of the dc busline side active resonant snubber assisted voltage source high frequency link soft switching PWM full-bridge dc-dc power converters acceptable for either utility ac 200V-rms or ac 400V-rms input grid. These high frequency switching dc-dc converters proposed in this paper are composed of a typical voltage source-fed full-bridge PWM inverter, high frequency transformer with center tap, high frequency diode rectifier with inductor input filter and dc busline side series switches with the aid of a dc busline parallel capacitive lossless snubber. All the active switches in the full-bridge arms as well as dc busline snubber can achieve ZCS turn-on and ZVS turn-off transition commutation with the aid of a transformer leakage inductive component and consequently the total switching power losses can be effectively reduced. So that, a high switching frequency operation of IGBTs in the voltage source full bridge inverter can be actually designed more than about 20 kHz. It is confirmed that the more the switching frequency of full-bridge soft switching inverter increases, the more soft switching PWM dc-dc converter with a high frequency transformer link has remarkable advantages for its power conversion efficiency and power density implementations as compared with the conventional hard switching PWM inverter type dc-dc power converter. The effectiveness of these new dc-dc power converter topologies can be proved to be more suitable for low voltage and large current dc-dc power supply as arc welding equipment from a practical point of view.

• Journal of Power Electronics
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• v.19 no.2
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• pp.353-362
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• 2019

To address the problem of circulating current loss in the traditional zero-current switching (ZCS) full-bridge (FB) DC/DC converter, a ZCS FB DC/DC converter topology and modulation strategy is proposed in this paper. The strategy can achieve ZCS turn on and zero-voltage and zero-current switching (ZVZCS) turn off for the primary switches and realize ZVZCS turn on and zero-voltage switching (ZVS) turn off for the auxiliary switches. Moreover, its resonant circuit power is small. Compared with the traditional phase shift full-bridge converter, the new converter decreases circulating current loss and does not increase the current stress of the primary switches and the voltage stress of the rectifier diodes. The diodes turn off naturally when the current decreases to zero. Thus, neither reverse recovery current nor loss on diodes occurs. In this paper, we analyzed the operating principle, steady-state characteristics and soft-switching conditions and range of the converter in detail. A 740 V/1 kW, 100 kHz experimental prototype was established, verifying the effectiveness of the converter through experimental results.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.3
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• pp.70-75
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• 2002

This paper proposes new single stage power factor correction (PFC) full bridge converter. The proposed converter is combined previous ZVS full bridge DC/DC converter with two inductors, two diodes, two magnetic coupling transformer for PFC. This process of power is isolated from the source and also regulate stable DC output voltage in a category. In this topology, the voltage stress of main switches is reduced by zero voltage switching. Moreover, the proposed converter doesn't need active PFC switch and auxiliarly circuits, like control and gating board, so it could decrease the size and cost and increase the efficiency.