scholarly journals An Experimental Comparison of Galvanically Isolated DC-DC Converters: Isolation Technology and Integration Approach

Electronics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1186
Author(s):  
Egidio Ragonese ◽  
Nunzio Spina ◽  
Alessandro Parisi ◽  
Giuseppe Palmisano

This paper reviews state‑of-the‑art approaches for galvanically isolated dc-dc converters based on radio frequency (RF) micro-transformer coupling. Isolation technology, integration level and fabrication issues are analyzed to highlight the pros and cons of fully integrated (i.e., two chips) and multichip systems-in-package (SiP) implementations. Specifically, two different basic isolation technologies are compared, which exploit thick‑oxide integrated and polyimide standalone transformers, respectively. To this aim, previously available results achieved on a fully integrated isolation technology (i.e., thick‑oxide integrated transformer) are compared with the experimental performance of a dc-dc converter for 20-V gate driver applications, specifically designed and implemented by exploiting a stand-alone polyimide transformer. The comparison highlights that similar performance in terms of power efficiency can be achieved at lower output power levels (i.e., about 200 mW), while the fully integrated approach is more effective at higher power levels with a better power density. On the other hand, the stand-alone polyimide transformer approach allows higher technology flexibility for the active circuitry while being less expensive and suitable for reinforced isolation.

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2328
Author(s):  
Egidio Ragonese ◽  
Alessandro Parisi ◽  
Nunzio Spina ◽  
Giuseppe Palmisano

This paper reviews state-of-the-art architectures for galvanically isolated DC–DC converters with data transmission for low-power applications. Such applications do not have stringent requirements, in terms of power efficiency, but ask for very compact, highly integrated implementations. To this aim, architecture simplicity is crucial, especially when data transmission and/or output power regulation are required. Since the bottleneck of galvanically isolated systems is the isolation device (i.e., typically a stacked thick oxide or polyimide transformer), the reduction of the number of isolated links, while preserving both power and data functionalities, is the more effective strategy to increase the level of integration, reduce the form factor, and have a lower cost per channel. Specifically, this review compares the pros and cons of different architectures that address this challenge differently from traditional solutions.


2021 ◽  
Vol 11 (4) ◽  
pp. 1597-1607
Author(s):  
Mohammed Jawad Zeinalabideen ◽  
Mazin Mohlab Al-Hilali ◽  
Andrey Savinkov

AbstractIn this study, an integrated approach of advanced spectral noise and high-precision temperature logging with production logging tool was used for the understanding of leak detection, fluid cross-flow, flow below spinner threshold, packer failure, fluid channeling in patchy and bad cement bond behind the casing, flow quantification in complex SSD completion, production detection and quantification in recirculation intervals in deviated wells. Various case studies from Southern and Northern Iraqi oil fields have been presented in this paper.


Proceedings ◽  
2021 ◽  
Vol 68 (1) ◽  
pp. 13
Author(s):  
Yixuan Sun ◽  
Stephen Beeby

This paper presents the COMSOL simulations of magnetically coupled resonant wireless power transfer (WPT), using simplified coil models for embroidered planar two-coil and four-coil systems. The power transmission of both systems is studied and compared by varying the separation, rotation angle and misalignment distance at resonance (5 MHz). The frequency splitting occurs at short separations from both the two-coil and four-coil systems, resulting in lower power transmission. Therefore, the systems are driven from 4 MHz to 6 MHz to analyze the impact of frequency splitting at close separations. The results show that both systems had a peak efficiency over 90% after tuning to the proper frequency to overcome the frequency splitting phenomenon at close separations below 10 cm. The four-coil design achieved higher power efficiency at separations over 10 cm. The power efficiency of both systems decreased linearly when the axial misalignment was over 4 cm or the misalignment angle between receiver and transmitter was over 45 degrees.


2009 ◽  
Author(s):  
Innocent Okoro ◽  
Jennifer Krolow ◽  
Djuro Novakovic ◽  
Adeniyi Aladesulu ◽  
Kendall Reynolds ◽  
...  

2004 ◽  
Vol 128 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Vassilios Pachidis ◽  
Pericles Pilidis ◽  
Fabien Talhouarn ◽  
Anestis Kalfas ◽  
Ioannis Templalexis

Background . This study focuses on a simulation strategy that will allow the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to be transferred to an engine system analysis carried out at a lower level of resolution. This work will enable component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. Approach. The technique described in this paper utilizes an object-oriented, zero-dimensional (0D) gas turbine modeling and performance simulation system and a high-fidelity, three-dimensional (3D) computational fluid dynamics (CFD) component model. The work investigates relative changes in the simulated engine performance after coupling the 3D CFD component to the 0D engine analysis system. For the purposes of this preliminary investigation, the high-fidelity component communicates with the lower fidelity cycle via an iterative, semi-manual process for the determination of the correct operating point. This technique has the potential to become fully automated, can be applied to all engine components, and does not involve the generation of a component characteristic map. Results. This paper demonstrates the potentials of the “fully integrated” approach to component zooming by using a 3D CFD intake model of a high bypass ratio turbofan as a case study. The CFD model is based on the geometry of the intake of the CFM56-5B2 engine. The high-fidelity model can fully define the characteristic of the intake at several operating condition and is subsequently used in the 0D cycle analysis to provide a more accurate, physics-based estimate of intake performance (i.e., pressure recovery) and hence, engine performance, replacing the default, empirical values. A detailed comparison between the baseline engine performance (empirical pressure recovery) and the engine performance obtained after using the coupled, high-fidelity component is presented in this paper. The analysis carried out by this study demonstrates relative changes in the simulated engine performance larger than 1%. Conclusions. This investigation proves the value of the simulation strategy followed in this paper and completely justifies (i) the extra computational effort required for a more automatic link between the high-fidelity component and the 0D cycle, and (ii) the extra time and effort that is usually required to create and run a 3D CFD engine component, especially in those cases where more accurate, high-fidelity engine performance simulation is required.


Author(s):  
B.T. Krishna ◽  
◽  
Shaik. mohaseena Salma ◽  

A flux-controlled memristor using complementary metal–oxide–(CMOS) structure is presented in this study. The proposed circuit provides higher power efficiency, less static power dissipation, lesser area, and can also reduce the power supply by using CMOS 90nm technology. The circuit is implemented based on the use of a second-generation current conveyor circuit (CCII) and operational transconductance amplifier (OTA) with few passive elements. The proposed circuit uses a current-mode approach which improves the high frequency performance. The reduction of a power supply is a crucial aspect to decrease the power consumption in VLSI. An offered emulator in this proposed circuit is made to operate incremental and decremental configurations well up to 26.3 MHZ in cadence virtuoso platform gpdk using 90nm CMOS technology. proposed memristor circuit has very little static power dissipation when operating with ±1V supply. Transient analysis, memductance analysis, and dc analysis simulations are verified practically with the Experimental demonstration by using ideal memristor made up of ICs AD844AN and CA3080, using multisim which exhibits theoretical simulation are verified and discussed.


Author(s):  
Bin Chen ◽  
Beatriz Ramos Barboza ◽  
Yanan Sun ◽  
Jie Bai ◽  
Hywel R Thomas ◽  
...  

AbstractAlong with horizontal drilling techniques, multi-stage hydraulic fracturing has improved shale gas production significantly in past decades. In order to understand the mechanism of hydraulic fracturing and improve treatment designs, it is critical to conduct modelling to predict stimulated fractures. In this paper, related physical processes in hydraulic fracturing are firstly discussed and their effects on hydraulic fracturing processes are analysed. Then historical and state of the art numerical models for hydraulic fracturing are reviewed, to highlight the pros and cons of different numerical methods. Next, commercially available software for hydraulic fracturing design are discussed and key features are summarised. Finally, we draw conclusions from the previous discussions in relation to physics, method and applications and provide recommendations for further research.


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