Integrated Current Balancing Transformer Based Input-Parallel Output-Parallel <i>LLC</i> Resonant Converter Modules

Ahmad, Ubaid; Cha, Honnyong; Naseem, Nabeel

doi:10.1109/tpel.2020.3026929

Cited by 58 publications

(7 citation statements)

References 25 publications

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“…Firstly, digital or analog output current controllers that force equal power sharing through modulation are possible, but require additional sensing circuits, control loops, and computational power and complexity. In [33,34], coupled inductors are used to force equal current sharing, but these cannot be arbitrarily modularized and cannot benefit from the fringing-field approach used here [25] to realize high-efficiency PCB inductors. Finally, the resonant capacitors or inductors can be electrically connected [32,35], which achieves good power balancing with a simple implementation but does not improve the power density or core losses.…”

Section: Paralleled Dc/dc Modulesmentioning

confidence: 99%

Conceptualization and Analysis of a Next-Generation Ultra-Compact 1.5-kW PCB-Integrated Wide-Input-Voltage-Range 12V-Output Industrial DC/DC Converter Module

et al. 2021

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The next-generation industrial environment requires power supplies that are compact, efficient, low-cost, and ultra-reliable, even across mains failures, to power mission-critical electrified processes. Hold-up time requirements and the demand for ultra-high power density and minimum production costs, in particular, drive the need for power converters with (i) a wide input voltage range, to reduce the size of the hold-up capacitor, (ii) soft-switching over the full input voltage and load ranges, to achieve low losses that facilitate a compact realization, and (iii) complete PCB-integration for low-cost manufacturing. In this work, we conceptualize, design, model, fabricate, and characterize a 1.5kW, 12 V-output DC/DC converter for industrial power supplies that is required to operate across a wide 300 V–430 V input voltage range. This module utilizes an LLC-based control scheme for complete soft-switching and a snake-core transformer to divide the output current with a balanced flux among multiple secondary windings. Detailed loss models are derived for every component in the converter. The converter achieves close to 96 peak efficiency with a power density of 337 W/3 ( 20.6kW/d3m), excellent matching to the derived loss models, and zero-voltage switching even down to zero load. The loss models are used to identify improvements to further boost efficiency, the most important of which is the minimization of delay times in synchronous rectification, and a subsequent improved 1.5kW hardware module eliminates nearly 25% of converter losses for a peak efficiency of nearly 97% with a power density of 308 W/3 ( 18.8kW/d3m). Two 1.5kW modules are then paralleled to achieve 3 kW output power at 12 V and 345 W/3 ( 21.1kW/d3m) with ideal current sharing between the secondary outputs and no drop in efficiency from a single module, an important characteristic enabled by the novel snake-core transformer.

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Section: Paralleled Dc/dc Modulesmentioning

confidence: 99%

Conceptualization and Analysis of a Next-Generation Ultra-Compact 1.5-kW PCB-Integrated Wide-Input-Voltage-Range 12V-Output Industrial DC/DC Converter Module

et al. 2021

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“…Liu et al 25 and Yang et al 26 propose a magnetic‐coupling method to achieve current balancing, but this method significantly increases the overall volume. Ahmad et al 27 propose an integrated magnetic current balancing transformer (ICBT), which can reduce the overall magnetic volume. In addition, a “Y” type connection transformer structure is proposed in Noah et al 28 to achieve current sharing by forcing the sum of these three resonant currents to be zero.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the inconvenience of active current sharing control, automatic passive current sharing method has attracted more and more attention because it does not need additional components and complex control strategies. For example, flying-capacitor technique, 20 common-inductor, 21,22 common-capacitor, 23 passive-impedancematching, 24 magnetic coupling, 25 integrated magnetic current balancing transformer, 26 "Y" type transformer, 27 and other methods 28 have been presented. Kirshenboim and Peretz 20 proposes a flying-capacitor structure, which by adding a capacitor to balance the current distribution automatically between phases and improve the power processing capacity.…”

mentioning

confidence: 99%

Bidirectional half‐bridge LLC resonant converter with automatic current sharing characteristic

Zhu

Liu

Jin

et al. 2023

Circuit Theory & Apps

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SummaryA bidirectional half‐bridge (BHB) LLC resonant converter with automatic current sharing characteristics is proposed in this paper for high‐power bidirectional energy storage applications. With the help of magnetizing inductance of transformer, all MOSFETs on the primary and secondary sides can realize zero‐voltage switching. By grouping the secondary windings of the transformer, excellent current sharing can be achieved in both forward and backward operation modes even if there is a 10% error of the resonant parameters. Due to the half bridge structure in both primary and secondary sides, the number of switches is reduced. And the resonant capacitance is small, which is conducive to integrate into the isolation transformer. Thus, the power density and overall efficiency of the proposed converter can be improved. Whether the converter is in forward or backward operation mode, the PWM control strategy is consistent, and it is not required to control the power flow by regulating the phase shift angle of primary and secondary sides, which makes the control strategy of the proposed converter easier. Finally, an 850 W experimental prototype is established to verify the superiority of the proposed circuit. Under the full load condition, the measured peak efficiency is 98.11% and 97.11% in the forward and backward operating modes, respectively.

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“…LLC resonant converter has been well studied in the power converter application field by its high frequency, good soft switching characteristics, and high conversion efficiency. In past studies, researchers have focused on the following aspects: changing the control strategy [2], changing the topology [3], using voltage-doubling rectification techniques [4], and module integration techniques [5]. In addition, researchers have spent much effort in improving the light-load efficiency [6].…”

Section: Introductionmentioning

confidence: 99%

Research on High Power Charging Power Supply Based on LLC and LCL-T Resonant Converter

Wang,

Fang,

2023

J. Phys.: Conf. Ser.

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Electric vehicle charging uses constant current followed by a constant voltage charging method, the MOSFETs operate over a large range of frequencies, which will cause trouble to the design of magnetic components, and the magnetizing current is circulated in the resonant tank, which will lead to more core loss. In this paper, a new resonant converter based on inductive multiplexing of LLC and LCL-T is studied to reduce the switching frequency range by using the inherent output characteristics of the converter. During the constant voltage charging phase, the LLC resonant tank operates as a constant voltage source to provide a stable charging voltage. In the LLC resonant tank, the resonant inductor is equated to the secondary side, and this resonant inductor is reused to develop the LCL-T resonant tank for the constant current charging stage, which is equivalent to a constant current source to provide a stable charging current. The resonant converter in this paper has lower losses and higher efficiency compared to other LLC resonant converters. A prototype with 3.3 kW is created to test the theoretical analysis.

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Integrated Current Balancing Transformer Based Input-Parallel Output-Parallel LLC Resonant Converter Modules

Cited by 58 publications

References 25 publications

Conceptualization and Analysis of a Next-Generation Ultra-Compact 1.5-kW PCB-Integrated Wide-Input-Voltage-Range 12V-Output Industrial DC/DC Converter Module

Conceptualization and Analysis of a Next-Generation Ultra-Compact 1.5-kW PCB-Integrated Wide-Input-Voltage-Range 12V-Output Industrial DC/DC Converter Module

Bidirectional half‐bridge LLC resonant converter with automatic current sharing characteristic

Research on High Power Charging Power Supply Based on LLC and LCL-T Resonant Converter

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