Zero-Voltage Switching Full-Bridge Converter With Reduced Filter Requirement and Wide ZVS Range for Variable Output Application

Aiming at the problems of narrow ZVS range, large duty cycle loss, and severe voltage oscillation of phase‐shift‐controlled full‐bridge converters, this paper proposes a converter that realizes ZVS by adjusting the parallel current. No additional series inductor is required, avoiding large duty cycle loss and weakening voltage oscillations on the secondary side. The converter with small duty cycle loss can use a transformer with a larger turns ratio, which can reduce the voltage stress of the secondary diodes and the filter inductor current ripple. The parallel current required to realize ZVS is analyzed theoretically considering the influence of leakage inductor energy on ZVS. A comparative experiment between the proposed converter and the conventional full‐bridge converter is carried out to verify the performance of the proposed converter.

Section: Introductionmentioning

confidence: 99%

“…The existing full bridge shares its lagging‐leg with an additional half‐bridge or a full bridge to broaden the ZVS range 7–10 . More additional components such as transformers, diodes, and energy storage devices are required, complicating the full‐bridge converter topology.…”

Section: Introductionmentioning

confidence: 99%

Wide zero‐voltage switching range full‐bridge converter based on adjustable parallel current

Gao

Tang

Wang

et al. 2023

“…In this frequency range, the switching loss will occupy a large proportion of the overall power loss of the power-switching device, so the ZVS capability of the PSFB converter will largely determine its efficiency. In order to widen the soft-switching range of PSFB converter, literature [9][10][11][12][13][14][15] proposed some methods to expand its ZVS range by adding auxiliary circuits. Among them, the literature [9][10][11][12][13] proposed some methods to broaden the ZVS capability by introducing passive components.…”

Section: Introductionmentioning

confidence: 99%

Efficiency optimization for phase‐shifted full‐bridge converter with variable frequency control

Tang,

Liu,

et al. 2023

In this paper, a control method combined with variable frequency and phase shifting is proposed, the primary purpose of which is to optimize the operating efficiency of the phase‐shift full‐bridge (PSFB) DC‐DC converter. By modeling the losses of the PSFB converter, the optimal switching frequency related to the load conditions is found. A neural network aided variable frequency controller that can work linearly is built to achieve the proposed method. At the same time, the voltage control loop is retained to ensure the stability of the output voltage and the necessary dynamic response of the converter. This paper builds an experimental platform for a 2 kW PSFB DC‐DC converter to verify the effectiveness of the proposed control method. With the control method proposed in this paper, the PSFB converter can always work at the optimum efficiency point under different load conditions. In addition, this paper also analyzes the influence of variable frequency control on PSFB operating states, such as zero‐voltage‐switching (ZVS) constraints, continuous conduction mode (CCM) operating states, and power density, which have an impact on its operating conditions.

mentioning

confidence: 99%

“…The research in previous works [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] is devoted to injecting parallel current i pr into the switches to help them realize ZVS. In Lim et al, 10 Chen et al, 11 Lee, 12,13 and Shi et al, 14 the PSFB converter and the half-bridge LLC converter share the lagging-leg switches to inject parallel current i pr into the lagging-leg. Although the lagging-leg switches are shared, these PSFB converters still require more additional devices, such as diodes, transformers, and energy storage devices, which will increase the cost and reduce the power density.…”

mentioning

confidence: 99%

Phase‐shifted full‐bridge converter based on an adjustable current auxiliary circuit with full load range ZVS and small duty cycle loss

Gao

Tang

Kan

et al. 2022

In this paper, a phase-shifted full-bridge converter based on an adjustable current auxiliary circuit is proposed. The converter's switches achieve ZVS with the help of the parallel current provided by the auxiliary circuit. The conduction loss of the parallel current is reduced since the magnitude of the current can be adjusted by the variable inductor. Since there is no additional series inductor, the duty cycle loss of the proposed converter is minimal. Moreover, the oscillating voltage on the secondary side decays quickly, indicating that the energy involved in the oscillation is small, which is beneficial to reduce the loss of the RCD. The experimental platform is built. On this basis, theoretical analysis and experimental verification are carried out in this paper.duty cycle loss, parallel current, phase-shifted full-bridge (PSFB), variable inductor, zerovoltage switching (ZVS) | INTRODUCTIONPhase shifted full bridge converters are widely used in communication, aerospace, and other fields because of their simple structure, ZVS characteristics, high reliability, and other advantages. However, the lagging-leg switches of conventional phase-shifted full-bridge converters cannot realize ZVS under light load, which will reduce the efficiency and cause electromagnetic interference. And the conduction loss of the primary side circulating current increases with the phase shift angle. Moreover, the voltage oscillation on the secondary side diode increases its voltage stress. These disadvantages limit the higher efficiency and higher power density of the PSFB converter.The PSFB converter first proposed in Steigerwald and Ngo 1 has a simple structure, including a full bridge, transformer, rectifier diode, and LC filter. At present, many improved topologies have been proposed to eliminate the above disadvantages. The common method is to increase the inductance in series with the transformer, which can be realized by adding a series inductor or increasing the leakage inductance of the transformer. 2,3 This method can broaden the ZVS range of switches; that is, the switches can realize ZVS under light load. However, the commutation of the primary side current is slow due to the increase of the series inductance, which leads to a large duty cycle loss under heavy load.