Analysis for High-frequency LLC Resonant Converter with Planar Transformer at Light-load Condition

2018 ◽  
Author(s):  
Keon-Woo Kim ◽  
Jae-Il Baek ◽  
Yeonho Jeong ◽  
Ki-Mok Kim ◽  
Gun-Woo Moon
Keyword(s):  
High Frequency ◽  
Load Condition ◽  
Resonant Converter ◽  
Light Load ◽  
Llc Resonant Converter

scholarly journals The Influence of Parasitic Components on LLC Resonant Converter

Energies ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 4305 ◽  
Author(s):  
Fang Li ◽  
Ruixiang Hao ◽  
Haodong Lei ◽  
Xinyi Zhang ◽  
Xiaojie You
Keyword(s):  
Load Condition ◽  
Equation Model ◽  
Soft Switching ◽  
Resonant Converter ◽  
Practical Applications ◽  
Conduction Loss ◽  
Light Load ◽  
Llc Resonant Converter ◽  
Simulation Results ◽  
Parasitic Components

In recent years, the LLC resonant converter has been widely used in DC–DC conversion applications. However, the parasitic components of the LLC resonant converter have a significant impact in practical applications, such as influence on the conduction loss and the soft-switching of power devices, the voltage oscillation across rectifier diodes, the unregulated output voltage at light load condition and so on. It is hard to analyze the higher-order circuits by the conventional analysis methods. Focusing on the operational principle of the LLC converter with parasitic components, the differential equation model is presented and solved by the numerical method in this paper. The simulation results verify the correctness of the theoretical analysis. The causes of two different frequency oscillations and the voltage spike are clarified. The design considerations and a specific example of the LLC converter are given. The experimental results are consistent with the simulation results, and the soft-switching of primary-side switches can be achieved in the prototype.

An 8kW LLC resonant converter in plasma power supply based on SiC power devices for efficiency improvement

Circuit World ◽  
2019 ◽  
Vol 45 (4) ◽  
pp. 181-188
Author(s):  
Zhenmin Wang ◽  
Wenyan Fan ◽  
Fangxiang Xie ◽  
Chunxian Ye
Keyword(s):  
Silicon Carbide ◽  
Power Supply ◽  
High Frequency ◽  
Experimental Results ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Plasma Power ◽  
Power Devices ◽  
Content Type ◽  
Llc Resonant Converter

Purpose This paper aims to present an 8 kW LLC resonant converter designed for plasma power supply with higher efficiency and lighter structure. It presents how to solve the problems of large volume and weight, low performance and low efficiency of traditional plasma power supply. Design/methodology/approach At present, conventional silicon (Si) power devices’ switching performance is close to the theoretical limit determined by its material properties; the next-generation silicon carbide (SiC) power devices with outstanding advantages can be used to optimal design. This 8 kW LLC resonant converter prototype with silicon carbide (SiC) power devices with a modulated switching frequency ranges from 100  to 400 kHz. Findings The experimental results show that the topology, switching loss, rectifier loss, transformer loss and drive circuit of the full-bridge LLC silicon carbide (SiC) plasma power supply can be optimized. Research limitations/implications Due to the selected research object (plasma power supply), this study may have limited universality. The authors encourage the study of high frequency resonant converters for other applications such as argon arc welding. Practical implications This study provides a practical application for users to improve the quality of plasma welding. Originality/value The experimental results show that the full-bridge LLC silicon carbide (SiC) plasma power supply is preferred in operation under conditions of high frequency and high voltage. And its efficiency can reach 98%, making it lighter, more compact and more efficient than previous designs.

scholarly journals Isolated AC/AC Converter with LLC Resonant Converter High Frequency Link and Four-Quadrant Switches in the Output Stage

2020 ◽  
Author(s):  
Leonardo Freire Pacheco ◽  
Ivo Barbi ◽  
Kaio Cesar Maciel Nascimento
Keyword(s):  
Power Distribution ◽  
High Frequency ◽  
Distribution Systems ◽  
Soft Switching ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Output Stage ◽  
Llc Resonant Converter ◽  
Four Quadrant ◽  
High Frequency Ac

An AC-AC converter with high-frequency link employing LLC resonant converter operating in the vicinity of the resonance frequency is studied, in which the output stage is unique and formed by a high-frequency AC-AC converter employing four quadrant switches. The topology, its operation and the modulation strategy are presented. The high-frequency stage switches located on the primary side of the transformer operate with soft switching of the ZVS type, while the four quadrant switches that form the output stage operate with soft switching of the ZCS type. Experimental data on a 1.5 kW experimental prototype that was designed, built and tested in the laboratory, with 220 VRMS input, 220 VRMS output and 40 kHz switching frequency are given in the paper. The studied converter can be considered a candidate for the building block of medium voltage solid-state transformers (SST) for power distribution systems.<br>

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