scholarly journals A Two-Stage 110VAC-to-1VDC Power Delivery Architecture Using Hybrid Converters for Data Centers and Telecommunication Systems

Author(s):  
Ratul Das ◽  
Hanh-Phuc Le

<p>Improving power delivery and management plays a key role in minimizing the cost of building and operating future green data centers to meet the fast growth of high-performance computing. Toward this important goal, this paper presents a new complete power delivery architecture to bridge AC grid voltages to core levels for computing loads using only 2 conversion stages with new converter topologies. The first stage converts a commercial AC line voltage of 90V-110V to a 48-60V intermediate bus with power factor correction (PFC). The second stage converts the bus voltage to core voltages of ~1 V with high current density and simple duty cycle control. Individually, the first stage was measured at 96.1% peak efficiency for output currents ranging in 0-4.5 A, while the second stage achieved 90.7% peak efficiency with a load range of 0-220 A at 1 V. Measured peak power densities are 73 W/in3 for the first stage and 2020 W/in3 for the second stage. In combination, the direct conversion from a line AC voltage of ~110 VAC to 1 VDC achieves a peak efficiency of 84.1% while providing output currents up to 160A.</p>

2021 ◽  
Author(s):  
Ratul Das ◽  
Hanh-Phuc Le

<p>Improving power delivery and management plays a key role in minimizing the cost of building and operating future green data centers to meet the fast growth of high-performance computing. Toward this important goal, this paper presents a new complete power delivery architecture to bridge AC grid voltages to core levels for computing loads using only 2 conversion stages with new converter topologies. The first stage converts a commercial AC line voltage of 90V-110V to a 48-60V intermediate bus with power factor correction (PFC). The second stage converts the bus voltage to core voltages of ~1 V with high current density and simple duty cycle control. Individually, the first stage was measured at 96.1% peak efficiency for output currents ranging in 0-4.5 A, while the second stage achieved 90.7% peak efficiency with a load range of 0-220 A at 1 V. Measured peak power densities are 73 W/in3 for the first stage and 2020 W/in3 for the second stage. In combination, the direct conversion from a line AC voltage of ~110 VAC to 1 VDC achieves a peak efficiency of 84.1% while providing output currents up to 160A.</p>


Author(s):  
John W. Coleman

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.


2021 ◽  
Author(s):  
Yuefeng Yu ◽  
Xun He ◽  
Rong Li ◽  
Xinglong Gou

Development of noble-metal-free high-performance bifunctional catalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is essential but challenging for hydrogen production from water electrolysis. Herein, amorphous bimetallic...


Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 486
Author(s):  
Yongjae Chun ◽  
Kyeore Han ◽  
Youpyo Hong

Owing to their advantages over hard disc drives (HDDs), solid-state drives (SSDs) are widely used in many applications, including consumer electronics and data centers. As erase operations are feasible only in block units, modification or deletion of pages cause invalidation of the pages in their corresponding blocks. To reclaim these invalid pages, the valid pages in the block are copied to other blocks, and the block with the invalid pages is initialized, which adversely affects the performance and durability of the SSD. The objective of a multi-stream SSD is to group data by their expected lifetimes and store each group of data in a separate area called a stream to minimize the frequency of wasteful copy-back and initialization operations. In this paper, we propose an algorithm that groups the data based on input/output (I/O) types and rewrite frequency, which show significant improvements over existing multi-stream algorithms not only for performance but also for effectiveness in covering most applications.


2009 ◽  
Author(s):  
Uri Cummings ◽  
Dan Daly ◽  
Rebecca Collins ◽  
Virat Agarwal ◽  
Fabrizio Petrini ◽  
...  

2017 ◽  
Vol 5 (24) ◽  
pp. 12330-12339 ◽  
Author(s):  
Norah Balahmar ◽  
Abdul Salam Al-Jumialy ◽  
Robert Mokaya

The direct conversion of biomass to activated carbons in a simple and lower cost one step process, which negates the need for hydrothermal carbonisation or pyrolysis, generates activated carbons with properties and CO2 uptake comparable or superior to those of conventionally prepared activated carbons.


2019 ◽  
Vol 12 (01) ◽  
pp. 1850104 ◽  
Author(s):  
Jinggao Wu ◽  
Qi Lai ◽  
Canyu Zhong

MoO3@CoMoO4 hybrid is fabricated by a facile one-step hydrothermal method and is used as anode for lithium-ion battery (LIB). Compared to pristine MoO3, galvanostatic charge–discharge tests show that the hybrid electrode delivered a remarkable rate capability of 586.69[Formula: see text]mAh[Formula: see text]g[Formula: see text] at the high current density of 1000[Formula: see text]mA[Formula: see text]g[Formula: see text] and a greatly enhanced cyclic capacity of 887.36[Formula: see text]mA[Formula: see text]h[Formula: see text]g[Formula: see text] after 140 cycles at the current density of 200[Formula: see text]mA[Formula: see text]g[Formula: see text] (with capacity retention, 85.3%). The superior electrochemical properties could be ascribed to the synergistic effect of MoO3 and CoO nanostructure that results in the lower charge transfer resistance and the higher Li[Formula: see text] diffusion coefficient, thus leading to high performance Li[Formula: see text] reversibility storage.


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