scholarly journals Design and Optimization of an Efficient (96.1%) and Compact (2 kW/dm3) Bidirectional Isolated Single-Phase Dual Active Bridge Ac–Dc Converter

2016 ◽  
Author(s):  
Jordi Everts
Keyword(s):  
Power Density ◽  
High Performance ◽  
Single Phase ◽  
Design Procedure ◽  
Cost Effective ◽  
Development Trend ◽  
Single Stage ◽  
Design And Optimization ◽  
Dual Active Bridge ◽  
Conversion Stage

The growing attention for plug-in electric vehicles, and the associated high-performance demands, have initiated a development trend towards highly efficient and compact on-board battery chargers. These isolated ac-dc converters are most commonly realized using two conversion stages, combining a non-isolated power factor correction (PFC) rectifier with an isolated dc-dc converter. This, however, involves two loss stages and a relatively high component count, limiting the achievable efficiency and power density and resulting in high costs. In this paper a single-stage converter approach is analyzed to realize a single-phase ac-dc converter, combining all functionalities into one conversion stage and thus enabling a cost-effective efficiency and power density increase. The converter topology consists of a quasi-lossless synchronous rectifier followed by an isolated dual active bridge (DAB) dc-dc converter, putting a small filter capacitor in between. To show the performance potential of this bidirectional, isolated ac-dc converter, a comprehensive design procedure and multi-objective optimization with respect to efficiency and power density is presented, using detailed loss and volume models. The models and procedures are verified by a 3.7 kW hardware demonstrator, interfacing a 400 V dc-bus with the single-phase 230 V, 50 Hz utility grid. Measurement results indicate a state-of-the-art efficiency of 96.1% and power density of 2.2 kW/dm3, confirming the competitiveness of the investigated single-stage DAB ac-dc converter.

Evaluation of Single Phase Immersion Cooling System for High Performance Server Chassis Using Dielectric Coolants

2020 ◽  
Author(s):  
Shuai Shao ◽  
Tianyi Gao ◽  
Huawei Yang ◽  
Jie Zhao ◽  
Jiajun Zhang
Keyword(s):  
Power Density ◽  
Thermal Performance ◽  
Data Center ◽  
High Performance ◽  
Single Phase ◽  
Cooling System ◽  
Thermal Power ◽  
Fluid Temperature ◽  
Primary Loop ◽  
Immersion Cooling

Abstract Along with advancements in microelectronics packaging, the power density of processor units has steadily increased over time. Data center servers equipped for high performance computing (HPC) often use multiple central processing units (CPUs) and graphical processing units (GPUs), thereby resulting in an increased power density, exceeding 1 kW per U. Many data center organizations are evaluating single phase immersion technology as a potential energy and resource saving cooling option. In this work immersion cooling was studied at a power level of 2.7kW/U with a 5U-height immersion cooling tank. Heat generated by a simulated GPU server was transferred to the secondary loop coolant, and then exchanged with the primary loop facility coolant through the heat exchanger. The chiller supply and return temperature and flow rate was controlled for the primary loop. The simulated GPU server chassis was designed to provide thermal power equivalent to a high power density server. Eight simulated power heaters, of which each unit was the size of a GPU chipset, was assembled in the comparable location to a real IT equipment on a 4U server chassis. Power for the GPU simulated chassis was able to support up to 2700 W maximum. Three investigations for this immersion cooling system evaluation were performed through comprehensive testing. The first is to identify the key decision making factor(s) for evaluating the thermal performance of 4 hydrocarbon-based dielectric coolants, including power parametric analysis, transient analysis, power cycling test, and fluid temperature profiling. The second is to develop an optimization strategy for the immersion system thermal performance. The third is to verify the capability of an 1U heat sink to support high density processor units over 300 W per GPU in an immersion cooling solution.

scholarly journals High Performance Single-Phase Single-Stage Grid-Tied PV Current Source Inverter Using Cascaded Harmonic Compensators

Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 380 ◽  
Author(s):  
Nahla E. Zakzouk ◽  
Ahmed K. Abdelsalam ◽  
Ahmed A. Helal ◽  
Barry W. Williams
Keyword(s):  
High Performance ◽  
Single Phase ◽  
Short Circuit ◽  
Current Source ◽  
Single Stage ◽  
Current Loop ◽  
Current Harmonics ◽  
Grid Current ◽  
Current Source Inverter ◽  
Low Order

In this paper, a single-phase single-stage photovoltaic (PV) grid-tied system is investigated. The conventional pulse width modulated (PWM) voltage source inverter (VSI) is replaced by a PWM current source inverter (CSI) for its voltage boosting capabilities, inherent short-circuit proof and higher reliability features. Modeling, design, and analysis of the considered CSI are presented altogether with enhanced proposed control loops aided with a modified PWM technique. DC-link even current harmonics are commonly reflected as low-order odd harmonics in the grid resulting in a poor quality grid current. In order to overcome the latter, a high performance proportional resonant controller, applied in the inverter inner grid current loop, is proposed using cascaded resonant control units tuned at low-order frequencies to eliminate injected grid current harmonics. Hence, with a less-bulky smoothing inductor at the CSI DC-side, grid power quality and system efficiency are simultaneously improved. Simulation and experimental results verify the proposed controller effectiveness.

scholarly journals Analytical modelling and power density optimisation of a single phase dual active bridge for aircraft application

2019 ◽  
Vol 2019 (17) ◽  
pp. 3671-3676 ◽  
Author(s):  
Niklas Fritz ◽  
Mohamed Rashed ◽  
Serhiy Bozhko ◽  
Fabrizio Cuomo ◽  
Pat Wheeler
Keyword(s):  
Power Density ◽  
Single Phase ◽  
Analytical Modelling ◽  
Dual Active Bridge ◽  
Aircraft Application

scholarly journals Ferrites and Nanocrystalline Alloys Applied to DC–DC Converters for Renewable Energies

2022 ◽  
Vol 12 (2) ◽  
pp. 709
Author(s):  
Dante Ruiz ◽  
Jorge Ortíz ◽  
Edgar Moreno ◽  
Claudio Fuerte ◽  
Vicente Venegas ◽  
...  
Keyword(s):  
Power Density ◽  
High Performance ◽  
Low Cost ◽  
Research Work ◽  
Design Procedure ◽  
Renewable Energies ◽  
Nanocrystalline Alloys ◽  
Core Material ◽  
The Core ◽  
Technical Specifications

The medium frequency transformer (MFT) with nanocrystalline alloys is quintessential in new DC–DC converters involved in various front-end applications. The center piece to achieve high-performance, efficient MFTs is the core. There are various options of core materials; however, no deep information is available about which material characteristics and design procedure combo are best to get high performance MFTs while operating at maximal power density. To provide new insights about interrelation between the selection of the core material with the compliance technical specifications, differently to other proposals, this research work aims to design and build, with the same methodology, two MFT prototypes at 20 kHz, with nanocrystalline and ferrite cores, to highlight power density, and overall performance and cost, as matching design criteria. As the experimental results show, a nanocrystalline core has the highest power density (36.91 kW/L), designed at 0.8 T to obtain low losses at 20 kHz, achieving an efficiency of 99.7%. The power density in the ferrite MFT is 56.4% lower than in the nanocrystalline MFT. However, regarding construction cost, the ferrite MFT is 46% lower, providing this a trend towards low-cost DC–DC converters. Finally, high power density in MFTs increases the power density of power DC–DC converters, which have relevant applications in fuel cell-supplied systems, renewable energies, electric vehicles, and solid-state transformers.

Solid-state Synthesis of Single-phase Nickel Monophosphosulfide for Oxygen Evolution Reaction

2021 ◽  
Author(s):  
Miao Wang ◽  
Ali Saad ◽  
Xiaoguang Li ◽  
Tao Peng ◽  
Qitao Zhang ◽  
...  
Keyword(s):  
Solid State ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
High Performance ◽  
Single Phase ◽  
Cost Effective ◽  
Metal Catalysts ◽  
Noble Metal Catalysts ◽  
Nonprecious Metal

High-performance and cost-effective nonprecious-metal catalysts are essential for next-generation oxygen evolution reaction (OER). However, the electrocatalysis of OER during water splitting is often carried out by noble metal catalysts, such...

Comprehensive Design and Optimization of a High-Power-Density Single-Phase Boost PFC

2009 ◽  
Vol 56 (7) ◽  
pp. 2574-2587 ◽  
Author(s):  
K. Raggl ◽  
T. Nussbaumer ◽  
G. Doerig ◽  
J. Biela ◽  
J.W. Kolar
Keyword(s):  
Power Density ◽  
High Power ◽  
Single Phase ◽  
High Power Density ◽  
Design And Optimization

scholarly journals Performance Comparison of Ferrite and Nanocrystalline Cores for Medium-Frequency Transformer of Dual Active Bridge DC-DC Converter

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2407
Author(s):  
Sakda Somkun ◽  
Toshiro Sato ◽  
Viboon Chunkag ◽  
Akekachai Pannawan ◽  
Pornnipa Nunocha ◽  
...  
Keyword(s):  
Phase Shift ◽  
Power Density ◽  
Single Phase ◽  
Performance Comparison ◽  
Experimental Results ◽  
High Permeability ◽  
Medium Frequency ◽  
Extended Phase ◽  
Mnzn Ferrite ◽  
Dual Active Bridge

This article reports an investigation into ferrite and nanocrystalline materials for the medium-frequency transformer of a dual active bridge DC-DC converter, which plays a key role in the converter’s efficiency and power density. E65 MnZn ferrite cores and toroidal and cut nanocrystalline cores are selected for the construction of 20-kHz transformers. Transformer performance is evaluated with a 1.1-kW (42–54 V)/400 V dual active bridge DC-DC converter with single-phase shift and extended phase shift modulations. The experimental results indicate that the toroidal nanocrystalline transformer had the best performance with an efficiency range of 98.5–99.2% and power density of 12 W/cm3, whereas the cut-core nanocrystalline transformer had an efficiency range of 98.4–99.1% with a power density of 9 W/cm3, and the ferrite transformer had an efficiency range of 97.6–98.8% with a power density of 6 W/cm3. A small mismatch in the circuit parameters is found to cause saturation in the nanocrystalline toroidal core, due to its high permeability. The analytical and experimental results suggest that cut nanocrystalline cores are suitable for the dual active bridge DC-DC converter transformers with switching frequencies up to 100 kHz.

Mineral/microfibrillated cellulose composite materials: High performance products, applications, and product forms

TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 507-515 ◽  
Author(s):  
David Skuse ◽  
Mark Windebank ◽  
Tafadzwa Motsi ◽  
Guillaume Tellier
Keyword(s):  
Composite Materials ◽  
High Performance ◽  
Aqueous Suspension ◽  
Production Capacity ◽  
Cost Savings ◽  
Cost Effective ◽  
New Materials ◽  
Wet Strength ◽  
Product Forms ◽  
Cellulose Composite

When pulp and minerals are co-processed in aqueous suspension, the mineral acts as a grinding aid, facilitating the cost-effective production of fibrils. Furthermore, this processing allows the utilization of robust industrial milling equipment. There are 40000 dry metric tons of mineral/microfbrillated (MFC) cellulose composite production capacity in operation across three continents. These mineral/MFC products have been cleared by the FDA for use as a dry and wet strength agent in coated and uncoated food contact paper and paperboard applications. We have previously reported that use of these mineral/MFC composite materials in fiber-based applications allows generally improved wet and dry mechanical properties with concomitant opportunities for cost savings, property improvements, or grade developments and that the materials can be prepared using a range of fibers and minerals. Here, we: (1) report the development of new products that offer improved performance, (2) compare the performance of these new materials with that of a range of other nanocellulosic material types, (3) illustrate the performance of these new materials in reinforcement (paper and board) and viscosification applications, and (4) discuss product form requirements for different applications.

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