scholarly journals Analysis, Design, and Implementation of Improved LLC Resonant Transformer for Efficiency Enhancement

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3288 ◽  
Author(s):  
Zhenxing Zhao ◽  
Qianming Xu ◽  
Yuxing Dai ◽  
Hanhang Yin
Keyword(s):  
Output Voltage ◽  
Efficiency Enhancement ◽  
Switching Loss ◽  
Conduction Loss ◽  
Wide Range ◽  
Llc Resonant Converter ◽  
Transformer Design ◽  
Analysis Design ◽  
Gain Adjustment ◽  
Secondary Winding

In battery charging applications, the charger changes its output voltage in a wide range during the charging process. This makes the design of LLC converters difficult to be optimized between the efficiency and the gain range. In this paper, an improved resonant transformer is presented for LLC resonant converter charger to improve the gain adjustment and charger efficiency. The resonant inductance and magnetizing inductance are integrated in the designed LLC transformer, and the magnetizing inductance can be adjusted dynamically with the change of output voltage and load, which is realized by a switch-controlled inductor (SCI) parallel to the secondary winding of transformer. The proposed transformer has 22.4% reduction in losses under full load conditions compared to conventional solutions. Moreover, the conduction loss and switching loss of LLC resonant tank are reduced by dynamically adjusting the magnetizing inductance, which improves the comprehensive efficiency of the whole charging process. The proposed transformer design is verified on a 720 W prototype.

scholarly journals Performance Modelling and Design Techniques for Efficiency Improvement in On-chip Switched-Capacitor DC-DC Converter

2022 ◽  
Author(s):  
Sunita Saini ◽  
Davinder Singh Saini
Keyword(s):  
Output Voltage ◽  
Optimization Technique ◽  
Switching Frequency ◽  
Switching Loss ◽  
Performance Modelling ◽  
Two Phase ◽  
Load Current ◽  
Vector Method ◽  
Conduction Loss ◽  
On Chip

Abstract Fundamental charge vector method analysis is a single parameter optimization technique limited to conduction loss assuming all frequency-dependent switching (parasitic) loss negligible. This paper investigates a generalized structure to design DC-DC SC converters based on conduction and switching loss. A new technique is proposed to find the optimum value of switching frequency and switch size to calculate target load current and output voltage that maximize the efficiency. The analysis is done to identify switching frequency and switch size for two-phase 2:1 series-parallel SC converter for a target load current of 2.67mA implemented on a 22nm technology node. Results show that a minimum of 250MHz switching frequency is required for target efficiency more than 90% and the output voltage greater than 0.85V where the switch size of a unit cell corresponds to 10Ω on-resistance. MATLAB and PSpice simulation tools are used for results and validation.

scholarly journals High Efficiency Isolated On-Board EV Battery Charger Using LLC Resonant Converter

2021 ◽  
Author(s):  
Sevilay Cetin ◽  
Keyword(s):  
Output Voltage ◽  
High Efficiency ◽  
Load Condition ◽  
Voltage Regulation ◽  
Resonant Converter ◽  
Battery Charger ◽  
Voltage Range ◽  
Wide Range ◽  
Electrical Vehicle ◽  
Llc Resonant Converter

In this study, high efficiency design of an on-board Electrical Vehicle (EV) battery charger is presented. The presented charger has two stages where the first stage is conventional front-end boost converter and the second stage is LLC resonant converter. The basic principles of both stage are discussed and the detailed design procedures are presented in terms of wide range output voltage regulation, wide range load condition, high efficiency and high power density. The presented design approach is tested with a prototype implemented with 2.5 kW output power at 250 V-450 V output voltage range. The peak efficiency of system is obtained as 95.53% at full load condition.

scholarly journals Accurate Prediction of Voltage Gain of the LLC Resonant Converter for EV battery Charge Applications

2018 ◽  
Vol 1 (1) ◽  
pp. 544-557 ◽  
Author(s):  
Sevilay Cetin
Keyword(s):  
Output Voltage ◽  
Harmonic Approximation ◽  
Voltage Regulation ◽  
Accurate Prediction ◽  
Switching Frequency ◽  
Voltage Gain ◽  
Resonant Converter ◽  
Battery Charge ◽  
Wide Range ◽  
Llc Resonant Converter

This work presents detailed analysis of LLC resonant converter to accurately predcit the voltage gain of the converter. Nowadays, Lithium-ion battery cells are mostly preferred for on-board electrical vehicle (EV) battery chargers due to their high power density. This results in wide range output voltage regulation for battery charger. The output voltage regulation of LLC resonant converter is provided by the changing of switching frequency. However, conventional first harmonic approximation (FHA) method applying for resonant power converters produces error below resonance frequency. Therefore, the objective of this paper is accurate prediction of the voltage gain characteristic for LLC resonant converter using in EV battery charge applications. The detailed theoretical anlysis of the LLC resonant converter is presented and the presented analysis is compared with a simulation study with 2.7 kW output power and 250 V-450 V output voltage range.

scholarly journals A Sub-Region Based Space Vector Modulation Scheme for Dual 2-Level Inverter System

2018 ◽  
Vol 8 (6) ◽  
pp. 4902
Author(s):  
R. Palanisamy ◽  
A. Velu ◽  
K. Selvakumar ◽  
D. Karthikeyan ◽  
D. Selvabharathi ◽  
...  
Keyword(s):  
Output Voltage ◽  
Modulation Scheme ◽  
Space Vector Modulation ◽  
Switching Loss ◽  
Space Vector ◽  
Dc Voltage ◽  
Multilevel Inverters ◽  
Harmonic Content ◽  
Voltage Stress ◽  
Vector Modulation

This paper deals the implementation of 3-level output voltage using dual 2-level inverter with control of sub-region based Space Vector Modulation (SR-SVM). Switching loss and voltage stress are the most important issues in multilevel inverters, for keep away from these problems dual inverter system executed. Using this proposed system, the conventional 3-level inverter voltage vectors and switching vectors can be located. In neutral point clamped multilevel inverter, it carries more load current fluctuations due to the DC link capacitors and it requires large capacitors. Based on the sub-region SVM used to control IGBT switches placed in the dual inverter system. The proposed system improves the output voltage with reduced harmonic content with improved dc voltage utilisation. The simulation and hardware results are verified using matlab/simulink and dsPIC microcontroller.

scholarly journals A Two-Degree-of-Freedom Cantilever-Based Vibration Triboelectric Nanogenerator for Low-Frequency and Broadband Operation

Electronics ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1526 ◽  
Author(s):  
Gang Tang ◽  
Fang Cheng ◽  
Xin Hu ◽  
Bo Huang ◽  
Bin Xu ◽  
...  
Keyword(s):  
Output Voltage ◽  
Low Frequency ◽  
Degree Of Freedom ◽  
Triboelectric Nanogenerator ◽  
Energy Harvesters ◽  
Harvesting Technique ◽  
Wide Range ◽  
Operating Bandwidth ◽  
Self Powered ◽  
Two Degree Of Freedom

With the continual increasing application requirements of broadband vibration energy harvesters (VEHs), many attempts have been made to broaden the bandwidth. As compared to adopted only a single approach, integration of multi-approaches can further widen the operating bandwidth. Here, a novel two-degree-of-freedom cantilever-based vibration triboelectric nanogenerator is proposed to obtain high operating bandwidth by integrating multimodal harvesting technique and inherent nonlinearity broadening behavior due to vibration contact between triboelectric surfaces. A wide operating bandwidth of 32.9 Hz is observed even at a low acceleration of 0.6 g. Meanwhile, the peak output voltage is 18.8 V at the primary resonant frequency of 23 Hz and 1 g, while the output voltage is 14.9 V at the secondary frequency of 75 Hz and 2.5 g. Under the frequencies of these two modes at 1 g, maximum peak power of 43.08 μW and 12.5 μW are achieved, respectively. Additionally, the fabricated device shows good stability, reaching and maintaining its voltage at 8 V when tested on a vacuum compression pump. The experimental results demonstrate the device has the ability to harvest energy from a wide range of low-frequency (<100 Hz) vibrations and has broad application prospects in self-powered electronic devices and systems.

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