scholarly journals Dual Interleaved LLC Converter for High Power Applications and Wide Load Range

2019 ◽  
Vol 25 (3) ◽  
pp. 4-9
Author(s):  
Michal Frivaldsky ◽  
Jan Morgos ◽  
Andrej Kanovsky
Keyword(s):  
High Power ◽  
High Efficiency ◽  
Negative Impact ◽  
Power Converter ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Load Range ◽  
High Switching Frequency ◽  
Llc Resonant Converter ◽  
Operational Range

Dual interleaved LLC resonant converter with half bridge topology of main circuit characterized by high switching frequency (500 kHz), high power density (60 W/inch3) and high efficiency (above 96 %) over entire operational range (20 %–100 %) is described. Focus was given on the practical design of power converter, which will be able to fulfil requirements on wide load range operation characterized by upcoming normative. Since proposed topology is based on dual interleaved LLC converter, the resonant component´s critical tolerance was also investigated to secure reliable and optimal operational point. Consequently, proposals for elimination of intolerance negative impact are also described. The results of theoretical analysis were verified directly through experimental measurements. Experimental results are finally compared with upcoming industrial standard 80 Plus Titanium.

scholarly journals A Comprehensive Overview in Control Algorithms for High Switching-Frequency LLC Resonant Converter

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4455
Author(s):  
Hwa-Pyeong Park ◽  
Mina Kim ◽  
Jee-Hoon Jung
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
High Power ◽  
Power Conversion ◽  
Voltage Regulation ◽  
Control Algorithms ◽  
Switching Frequency ◽  
Resonant Converter ◽  
High Switching Frequency ◽  
Llc Resonant Converter

An LLC resonant converter has been widely used in various industrial applications because of its high cost-effectiveness, high power conversion efficiency, simple design methodology, and simple control algorithms using a pulse frequency modulation (PFM). In addition, the soft switching capability of the LLC resonant converter is good to obtain high switching frequency operations, which can get the high-power density of the power converter. Over the past years, several studies have been conducted to improve the performance of a high switching frequency LLC resonant converter with resonant tank design, optimal power stage design, and enhanced control algorithms. This paper is the review paper in terms of the control algorithms for the LLC resonant converter. It focuses on the overview of the high switching-frequency LLC resonant converter in terms of the control algorithms. The advanced control algorithm can improve power conversion efficiency, dynamic performance, tight output voltage regulation, and small electro-magnetic interference. The operational principles of the control algorithms are briefly explained to show their own characteristics and advantages. Thereafter, the research issues for the future works will be discussed in the conclusion.

scholarly journals High-Frequency LLC Resonant Converter with GaN Devices and Integrated Magnetics

Energies ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1781 ◽  
Author(s):  
Yu-Chen Liu ◽  
Chen Chen ◽  
Kai-De Chen ◽  
Yong-Long Syu ◽  
Meng-Chi Tsai
Keyword(s):  
High Frequency ◽  
High Efficiency ◽  
Power Converter ◽  
Maximum Efficiency ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Leakage Inductance ◽  
Llc Resonant Converter ◽  
Resonant Inductor ◽  
Secondary Side

In this study, a light emitting diode (LED) driver containing an integrated transformer with adjustable leakage inductance in a high-frequency isolated LLC resonant converter was proposed as an LED lighting power converter. The primary- and secondary-side topological structures were analyzed from the perspectives of component loss and component stress, and a full-bridge structure was selected for both the primary- and secondary-side circuit architecture of the LLC resonant converter. Additionally, to achieve high power density and high efficiency, adjustable leakage inductance was achieved through an additional reluctance length, and the added resonant inductor was replaced with the transformer leakage inductance without increasing the amount of loss caused by the proximity effect. To optimize the transformer, the number of primary- and secondary-side windings that resulted in the lowest core loss and copper loss was selected, and the feasibility of the new core design was verified using ANSYS Maxwell software. Finally, this paper proposes an integrated transformer without any additional resonant inductor in the LLC resonant converter. Transformer loss is optimized by adjusting parameters of the core structure and the winding arrangement. An LLC resonant converter with a 400 V input voltage, 300 V output voltage, 1 kW output power, and 500 kHz switching frequency was created, and a maximum efficiency of 97.03% was achieved. The component with the highest temperature was the transformer winding, which reached 78.6 °C at full load.

scholarly journals Hybrid Multimodule DC-DC Converters for Ultrafast Electric Vehicle Chargers

Energies ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4949
Author(s):  
Mena ElMenshawy ◽  
Ahmed Massoud
Keyword(s):  
Power Density ◽  
High Power ◽  
High Efficiency ◽  
Controller Design ◽  
Power Level ◽  
Power Converter ◽  
Total Power ◽  
Switching Frequency ◽  
High Power Density ◽  
High Switching Frequency

To increase the adoption of electric vehicles (EVs), significant efforts in terms of reducing the charging time are required. Consequently, ultrafast charging (UFC) stations require extensive investigation, particularly considering their higher power level requirements. Accordingly, this paper introduces a hybrid multimodule DC-DC converter-based dual-active bridge (DAB) topology for EV-UFC to achieve high-efficiency and high-power density. The hybrid concept is achieved through employing two different groups of multimodule converters. The first is designed to be in charge of a high fraction of the total required power, operating at a relatively low switching frequency, while the second is designed for a small fraction of the total power, operating at a relatively high switching frequency. To support the power converter controller design, a generalized small-signal model for the hybrid converter is studied. Also, cross feedback output current sharing (CFOCS) control for the hybrid input-series output-parallel (ISOP) converters is examined to ensure uniform power-sharing and ensure the desired fraction of power handled by each multimodule group. The control scheme for a hybrid eight-module ISOP converter of 200 kW is investigated using a reflex charging scheme. The power loss analysis of the hybrid converter is provided and compared to conventional multimodule DC-DC converters. It has been shown that the presented converter can achieve both high efficiency (99.6%) and high power density (10.3 kW/L), compromising between the two other conventional converters. Simulation results are provided using the MatLab/Simulink software to elucidate the presented concept considering parameter mismatches.

scholarly journals High Frequency, High Efficiency, and High Power Density GaN-Based LLC Resonant Converter: State-of-the-Art and Perspectives

2021 ◽  
Vol 11 (23) ◽  
pp. 11350
Author(s):  
Seyed Abolfazl Mortazavizadeh ◽  
Simone Palazzo ◽  
Arturo Amendola ◽  
Enzo De Santis ◽  
Dario Di Ruzza ◽  
...  
Keyword(s):  
Power Density ◽  
High Power ◽  
High Frequency ◽  
High Efficiency ◽  
Resonant Converters ◽  
Switching Frequency ◽  
High Power Density ◽  
Resonant Converter ◽  
Gan Hemt ◽  
Llc Resonant Converter

Soft switching for both primary and secondary side devices is available by using LLC converters. This resonant converter is an ideal candidate for today’s high frequency, high efficiency, and high power density applications like adapters, Uninterrupted Power Supplies (UPS), Solid State Transformers (SST), electric vehicle battery chargers, renewable energy systems, servers, and telecom systems. Using Gallium-Nitride (GaN)-based power switches in this converter merits more and more switching frequency, power density, and efficiency. Therefore, the present paper focused on GaN-based LLC resonant converters. The converter structure, operation regions, design steps, and drive system are described precisely. Then its losses are discussed, and the magnets and inductance characteristics are investigated. After that, various interleaved topologies, as a solution to improve power density and decrease current ripples, have been discussed. Also, some challenges and concerns related to GaN-based LLC converters have been reviewed. Commercially available power transistors based on various technologies, i.e., GaN HEMT, Silicon (Si) MOSFET, and Silicon Carbide (SiC) have been compared. Finally, the LLC resonant converter has been simulated by taking advantage of LTspice and GaN HEMT merits, as compared with Si MOSFETs.

scholarly journals A Si-FET-Based High Switching Frequency Three-Level LLC Resonant Converter

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3082
Author(s):  
Yang ◽  
Han
Keyword(s):  
Optimal Design ◽  
High Performance ◽  
Input Voltage ◽  
Switching Frequency ◽  
Design Consideration ◽  
Resonant Converter ◽  
Switching Losses ◽  
High Switching Frequency ◽  
Llc Resonant Converter ◽  
Resonant Inductor

This paper highlights the proposed silicon field-effect transistor (Si-FET)-based high switching frequency three-level (TL) LLC resonant converter. It provides a detailed operational analysis of the converter; the multilevel (ML) organization of cells; voltage-balancing principles; current-balancing principles; loss comparison between Si-FETs and gallium-nitride (GaN)-FETs; and an optimal design consideration based on loss analysis. This analysis reveals that the switching losses of all power switches can be considerably reduced as the voltage across each switch can be set to half of the input voltage without an additional circuit or control strategy. Moreover, the current of each resonant inductor is automatically balanced by a proposed integrated magnetic (IM)-coupled inductor. Therefore, the operating frequency can be easily increased to near 1 MHz without applying high-performance switches. In addition, the resonant tanks of the converter can be a group of cells for multilevel operation, which indicates that the voltage across each switch is further reduced as more cells are added. Based on the results of the analysis, an optimal design consideration according to the resonant tank and switching frequency is discussed. The proposed converter was validated via a prototype converter with an input of 390 V, an output of 19.5 V/18 A, and a frequency of 1 MHz.

Investigation on Type-4 and Type-11 Mixed Topology of LLC Resonant Converter

2014 ◽  
Vol 960-961 ◽  
pp. 1254-1257
Author(s):  
Xiang Wu Yan ◽  
Lei Sun ◽  
Bo Zhang ◽  
Zheng Lv
Keyword(s):  
Topological Group ◽  
Resonant Frequency ◽  
Influence Factors ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Simulation Environment ◽  
Load Range ◽  
Small Fluctuation ◽  
Wide Range ◽  
Llc Resonant Converter

LLC resonant converter can adjust the output for a wide range of source and load with a small fluctuation of switching frequency, so it is used widely. This paper introduces all arrangements of LLC topological group, then proposes a new topology which is consist of Type-4 and Type-11 that used widely,in this paper we also give its calculate method of resonant frequency. Lastly we get gain characteristics of the topologies in the PSpice simulation environment and analyse the influence factors on adjustment ability in certain load range .

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