llc resonant converter
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Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 315
Author(s):  
Qianfan Zhou ◽  
Yang Liu ◽  
Zongjian Li ◽  
Zhixing He

In this paper, a coupled-inductor interleaved LLC resonant converter (CI-ILLC) was proposed, which can achieve extensive operation range applications by multiplexing inductors and switches. In this proposed CI-ILLC, the coupled-inductor not only serves as a filter inductor but also plays the role of transformer to improve the power density. By changing the modulation methods, the proposed converter can work at three modes for a wide operation range, namely high gain (HG) mode, medium gain (MG) mode, and low gain (LG) mode. Moreover, the interleaved structure greatly reduces the current ripple and current stress of switches. Besides, in HG and MG modes, all switches can realize zero-voltage switching, with high energy transmission efficiency. Finally, the simulation and experiment results of the prototype with 120–200 V input and 50–200 V output are presented to verify the viability of the proposed converter.


2021 ◽  
Vol 12 (1) ◽  
pp. 42
Author(s):  
Arslan Arif ◽  
Junaid Arshad ◽  
Shahid Iqbal

Technological advancements in solar power systems necessitate highly reliable power inverters with a high efficiency and a small size. An LLC resonant converter-based pseudo Direct Current (DC) link inverters offer these qualities to some extent. The resonant circuits of conventional pseudo DC link inverters lack the ability to attain a zero gain and cannot handle variable frequency control which in turn requires very large filters to produce pure sinusoidal output voltages for grid. The usage of these filters consequences in the enhanced price and size of inverters; moreover, the reliability of inverters is also reduced. We propose a novel topology for a pseudo DC link inverter based on an LLCLC resonant converter. The proposed inverter does not require large filters, because it generates rectified sinusoidal output voltages. An additional parallel LC component is added in series to the resonant circuit, which makes it able to attain a zero gain through an infinite circuit impedance. The 400 W pseudo DC link inverter with a 40 V input and a 400 V output is designed and simulated on OrCAD PSpice software. The results showed that there is a significant improvement in achieving a zero gain. The possible lowest gain achieved is approximately 0.125. The proposed technique attested to be more efficient than those formerly used, subsequently contributing satisfying outcomes.


2021 ◽  
Vol 13 (1) ◽  
pp. 2
Author(s):  
Houssein Al Attar ◽  
Mohamed Assaad Hamida ◽  
Malek Ghanes ◽  
Miassa Taleb

Electric Vehicle (EV) bidirectional charger technology is growing in importance. It defines the fact of returning the electricity stored in the batteries of EV to Grid (V2G), to Home (V2H), to Load (V2L), or in one word V2X mode. The EV onboard charger is divided into two parts: AC-DC and DC-DC converters. The isolated bidirectional DC-DC LLC resonant converter is used to improve the charger efficiency within both battery power and voltage ranges. It is controlled by varying the switching frequency based on a small signal modeling approach using the gain transfer function inversion method. The dimensions of the DC-DC LLC converter directly affect the charger cost. Moreover, they cause an important control frequency saturation zone, especially in V2X mode, where the switching frequency is out of the feasibility zone. The new challenge in this paper is to design an optimization strategy to minimize the LLC converter cost and improve the control frequency feasibility zone, for a wide variation of battery voltage and converter power, in the charging (G2V) and discharging (V2X) modes simultaneously. For our best knowledge, this optimization problem, in the case of a bidirectional (G2V and V2X) charger, is not yet considered in the literature. An optimal design that considers the control stability equations in the optimization algorithm is elaborated. The obtained results show a significant converter cost decrease and important expansion of control frequency feasibility zones. A comparative study between initial and optimized values, in G2V and V2X modes, is generated according to the converter efficiency.


2021 ◽  
Vol 6 (4) ◽  
pp. 263-275
Author(s):  
Yuqi Wei ◽  

To achieve the constant current (CC) and constant voltage (CV) charge of the lithium battery, the traditional LLC resonant converter requires the switching frequency varies in a wide range, which brings difficulty to the magnetic components design, and the system efficiency would also be degraded. In this article, a novel topology based on LLC and LCL-T resonant tanks is proposed to reduce the range of operating switching frequency. During the CC charge state, the proposed converter is operating with the LCL-T resonant tank, and it can be regarded as a current source, which provides constant charging current to the battery. During the CV charge state, the LCL-T resonant tank is bypassed and the structure of the proposed converter is modified to a traditional LLC resonant converter, and it is functioning as a CV source. Owing to the high accuracy of the CC and voltage sources, the required operating switching frequency range can be significantly reduced when compared with traditional LLC approaches. Operational principles and design guidelines for the proposed converter are described. Experiment and simulation results from a 180 W prototype are provided to validate the theoretical analysis.


2021 ◽  
Vol 2136 (1) ◽  
pp. 012021
Author(s):  
Fanghui Zhang ◽  
Huimin Qiu

Abstract The photoelectric properties of LED are affected by driving current and ambient temperature. To solve the problem of light wane caused by excessive current and overheating, LLC resonant converter with soft switching was chosen as the main topology, improving the power efficiency, and reducing the heat of the LED driver. Firstly, the soft-switching conditions of the LLC resonant converter are analyzed, and the constraint equation is obtained. Then, an improved particle swarm optimization algorithm is proposed to optimize the resonant parameters. The weight of particles is dynamically and adaptively changed to balance the global and local optimization performance of particles. Finally, the controller is designed to realize constant current. This design improves the efficiency of the LED driver. At the same time, the light wane is effectively suppressed by stable output current, and the rationality of the selected parameters is verified by simulation and experiment.


2021 ◽  
Vol 11 (23) ◽  
pp. 11350
Author(s):  
Seyed Abolfazl Mortazavizadeh ◽  
Simone Palazzo ◽  
Arturo Amendola ◽  
Enzo De Santis ◽  
Dario Di Ruzza ◽  
...  

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.


Author(s):  
Kaiyuan Wu ◽  
Yifei Wang ◽  
Xuanwei Cao ◽  
Jiatong Zhan ◽  
Xiaobin Hong ◽  
...  

2021 ◽  
Author(s):  
Xing-Rou Chen ◽  
Kang-Shi Liu ◽  
Da-Wei Liu ◽  
Yu-Chen Liu ◽  
Huang-Jen Chiu

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