scholarly journals A Control Method to Improve Power Conversion Efficiency of Three-level NPC-Based Dual Active Bridge Converter

2017 ◽  
Vol 22 (2) ◽  
pp. 150-158
Author(s):  
Jun-Young Lee ◽  
Hyun-Jun Choi ◽  
Ju-Yong Kim ◽  
Jee-Hoon Jun
Author(s):  
Ahmed M. Ali ◽  
Dirk Söffker

Optimal power management in real-time is a core technology of hybrid electric vehicles (HEVs). The online application of optimized power split ratios based on driver demand is a promising approach allowing near optimal power handling decisions in real-time. However, the fulfillment of exact power delivery (driveability) is an open challenge of this approach due to interpolation of driver’s demand to the optimized discrete solutions. Finding balanced power management that handles unscheduled loads and sustains required power conversion efficiency may significantly improve the experimental application of this approach. This work proposes an observer-based control method integrated to the power management system that ensures better driveability with minimal effect on power handling optimality. Modeling of traction system for observer design is based on a simplified brushless DC motor model. Identification of system parameters is achieved by a newly introduced error minimization algorithm using NSGA-II to obtain the same dynamic response as the original system. Results analysis shows 7% reduction of power consumption and 98% improvement of driveability at minimal mitigation of power conversion efficiency.


Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2237 ◽  
Author(s):  
Tomoharu Yada ◽  
Yuta Katamoto ◽  
Hiroaki Yamada ◽  
Toshihiko Tanaka ◽  
Masayuki Okamoto ◽  
...  

This paper deals with a design and experimental verification of 400-W class light-emitting diode (LED) driver with cooperative control method for two-parallel connected DC/DC converters. In the cooperative control method, one DC/DC converter is selected to supply the output current for the LED, based on the reference value of the LED current. Thus, the proposed cooperative-control strategy achieves wide dimming range operation. The discontinuous current conduction mode (DCM) operation improves the total harmonic distortion (THD) value on the AC side of the LED driver. The standard of Electrical Applications and Materials Safety Act in Japan has defined the flicker frequency and minimum optical output. The smoothing capacitors are designed by considering the power flow and LED current ripple for satisfying the standard. A prototype LED driver is constructed and tested. Experimental results demonstrate that a wide dimming operation range from 1 to 100% is achieved with a THD value less than 10% on the AC side, by the proposed control strategy. The authors compare the power conversion efficiency between Si- and SiC-metal-oxide-semiconductor field-effect transistors (MOSFETs) based LED driver. The maximum power conversion efficiency by using SiC-MOSFETs based LED driver is 91.4%. Finally, the variable switching frequency method is proposed for improving the power conversion efficiency for a low LED current region.


Nanoscale ◽  
2019 ◽  
Vol 11 (45) ◽  
pp. 21824-21833 ◽  
Author(s):  
Jyoti V. Patil ◽  
Sawanta S. Mali ◽  
Chang Kook Hong

Controlling the grain size of the organic–inorganic perovskite thin films using thiourea additives now crossing 2 μm size with >20% power conversion efficiency.


2019 ◽  
Vol 16 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Hui Zhang ◽  
Yibing Ma ◽  
Youyi Sun ◽  
Jialei Liu ◽  
Yaqing Liu ◽  
...  

In this review, small-molecule donors for application in organic solar cells reported in the last three years are highlighted. Especially, the effect of donor molecular structure on power conversion efficiency of organic solar cells is reported in detail. Furthermore, the mechanism is proposed and discussed for explaining the relationship between structure and power conversion efficiency. These results and discussions draw some rules for rational donor molecular design, which is very important for further improving the power conversion efficiency of organic solar cells based on the small-molecule donor.


2019 ◽  
Vol 7 (15) ◽  
pp. 9025-9033 ◽  
Author(s):  
Jin-Feng Liao ◽  
Wu-Qiang Wu ◽  
Jun-Xing Zhong ◽  
Yong Jiang ◽  
Lianzhou Wang ◽  
...  

A multifunctional 2D polymeric semiconductor was incorporated to provide surprisingly robust efficacy in grain boundary functionalization and defect passivation of perovskite, which suppresses charge recombination and thus affording an illustrious photovoltage of 1.16 V and power conversion efficiency of 21.1%.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhenrong Jia ◽  
Shucheng Qin ◽  
Lei Meng ◽  
Qing Ma ◽  
Indunil Angunawela ◽  
...  

AbstractTandem organic solar cells are based on the device structure monolithically connecting two solar cells to broaden overall absorption spectrum and utilize the photon energy more efficiently. Herein, we demonstrate a simple strategy of inserting a double bond between the central core and end groups of the small molecule acceptor Y6 to extend its conjugation length and absorption range. As a result, a new narrow bandgap acceptor BTPV-4F was synthesized with an optical bandgap of 1.21 eV. The single-junction devices based on BTPV-4F as acceptor achieved a power conversion efficiency of over 13.4% with a high short-circuit current density of 28.9 mA cm−2. With adopting BTPV-4F as the rear cell acceptor material, the resulting tandem devices reached a high power conversion efficiency of over 16.4% with good photostability. The results indicate that BTPV-4F is an efficient infrared-absorbing narrow bandgap acceptor and has great potential to be applied into tandem organic solar cells.


2021 ◽  
pp. 1-11
Author(s):  
Miguel Catela ◽  
Dawei Liang ◽  
Cláudia R. Vistas ◽  
Dário Garcia ◽  
Bruno D. Tibúrcio ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Wageh ◽  
Mahfoudh Raïssi ◽  
Thomas Berthelot ◽  
Matthieu Laurent ◽  
Didier Rousseau ◽  
...  

AbstractPoly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) mixed with single-wall nanotubes (SWNTs) (10:1) and doped with (0.1 M) perchloric acid (HClO4) in a solution-processed film, working as an excellent thin transparent conducting film (TCF) in organic solar cells, was investigated. This new electrode structure can be an outstanding substitute for conventional indium tin oxide (ITO) for applications in flexible solar cells due to the potential of attaining high transparency with enhanced conductivity, good flexibility, and good durability via a low-cost process over a large area. In addition, solution-processed vanadium oxide (VOx) doped with a small amount of PEDOT-PSS(PH1000) can be applied as a hole transport layer (HTL) for achieving high efficiency and stability. From these viewpoints, we investigate the benefit of using printed SWNTs-PEDOT-PSS doped with HClO4 as a transparent conducting electrode in a flexible organic solar cell. Additionally, we applied a VOx-PEDOT-PSS thin film as a hole transporting layer and a blend of PTB7 (polythieno[3,4-b] thiophene/benzodithiophene): PC71BM (phenyl-C71-butyric acid methyl ester) as an active layer in devices. Zinc oxide (ZnO) nanoparticles were applied as an electron transport layer and Ag was used as the top electrode. The proposed solar cell structure showed an enhancement in short-circuit current, power conversion efficiency, and stability relative to a conventional cell based on ITO. This result suggests a great carrier injection throughout the interfacial layer, high conductivity and transparency, as well as firm adherence for the new electrode.


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