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 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 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.

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 Non-isolated LLC resonant DC-DC converter with balanced rectifying current and stress

2020 ◽  
Vol 18 (2) ◽  
pp. 698
Author(s):  
Abdulhakeem Mohammed Dobi ◽  
Mohd Rodhi Sahid
Keyword(s):  
Experimental Result ◽  
Resonant Converters ◽  
Resonant Converter ◽  
Secondary Current ◽  
Zero Current Switching ◽  
Zero Current ◽  
Llc Resonant Converter ◽  
Resonant Inductor ◽  
Current Unbalance ◽  
Secondary Side

<p><span>In isolated type LLC resonant converters, transformer leakage inductances can be merged with the resonant inductor to extend the ZVS capability of the switches apart from isolation and voltage scaling. However, the transformer presents a resonant imbalance in the secondary side leading to secondary current unbalance, an increase in RMS value of the secondary current and increase thermal stress. This paper proposed a half-bridge non-isolated LLC resonant converter with a balanced rectifying current and stress in the rectifier diodes. The proposed converter can achieve the most advantages of isolated LLC converters, such as ZVS and low MOSFET turn-off loss. By the non-isolation method, secondary current and, transformer loss is significantly reduced. In addition, rectifier diodes operate with zero current switching and balanced rectifying current and stress over the entire operating range. The proposed non-isolated structure is verified by the experimental result with a 60W LLC resonant converter. </span></p>

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>

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.

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>

scholarly journals A Phase-Shift-Modulated LLC-Resonant Micro-Inverter Based on Fixed Frequency Predictive-MPPT

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1460
Author(s):  
Omar Abdel-Rahim ◽  
Nehmedo Alamir ◽  
Mohamed Abdelrahem ◽  
Mohamed Orabi ◽  
Ralph Kennel ◽  
...  
Keyword(s):  
High Efficiency ◽  
Harmonic Distortion ◽  
Maximum Power ◽  
Switching Frequency ◽  
Resonant Converter ◽  
Fixed Frequency ◽  
Pv System ◽  
Partial Shading ◽  
Llc Resonant Converter ◽  
Micro Inverter

Maximum Power Point Tracking (MPPT) control is an essential part of every photovoltaic (PV) system, in order to overcome any change in ambient environmental conditions and ensure operation at maximum power.. Recently, micro-inverters have gained a lot of attention due to their ability to track the true MPP for each individual PV module, which is considered a powerful solution to overcome the partial shading and power mismatch problems which exist in series-connected panels. Although the LLC resonant converter has high efficiency and high boosting ability, traditional MPPT techniques based on Pulse Width Modulation (PWM) do not work well with it. In this paper, a fixed frequency predictive MPPT technique is presented for the LLC resonant converter to be used as the first-stage in a PV micro-inverter. Using predictive control enhances the tracking efficiency and reduces the steady state oscillation. Operation with fixed switching frequency for the LLC resonant converter improves the total harmonic distortion profile of the system and ease the selection of circuit magnetic component. To demonstrate the effectiveness of the proposed MPPT technique, the system is simulated using MATLAB/Simulink platform. Furthermore, a 150 W hardware prototype is developed and tested. Both simulation and experimental results are consistent and validate the proper operation of the developed system.

scholarly journals LLC Resonant Converter for LEV (Light Electric Vehicle) Fast Chargers

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 362 ◽  
Author(s):  
Do-Hyun Kim ◽  
Min-Soo Kim ◽  
Sarvar Hussain Nengroo ◽  
Chang-Hee Kim ◽  
Hee-Je Kim
Keyword(s):  
Electric Vehicle ◽  
High Efficiency ◽  
Lithium Ion ◽  
Transient State ◽  
Constant Current ◽  
Maximum Efficiency ◽  
Resonant Converter ◽  
Switching Loss ◽  
Super Capacitor ◽  
Llc Resonant Converter

This paper presents a Light Electric Vehicle (LEV) fast charger with a Lithium-Ion Battery (LIB) and Super-Capacitor (SC). The LEV fast charger consists of an AC/DC rectifier and LLC (Inductor-Inductor-Capacitor) resonant Full bridge converter. The LLC resonant converter has high-efficiency and low switching loss because of Zero Voltage Switching (ZVS). So, it is used widely in the industry. In general, the fast charger algorithm uses the Constant Current (CC) mode and Constant Voltage (CV). The CC mode starts at first and then the CV mode finishes. However, there is a big control value gap between the CC mode and CV mode. Therefore, when changing from CC to CV, the transient state occurs. To compensate for the transient state, we propose a new control algorithm. By means of this algorithm, we can achieve a higher level of safety and stability. The fast charger with LIB of 800 Wh and SC of 50 Wh is analyzed and verified, and we obtain a maximum efficiency of 96.4%. The discussions are validated using the LLC resonant full bridge converter prototype at the laboratory level.

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