scholarly journals Improved Modulation Strategy Based on Minimum Energy Storage Principle for Electrolytic-Capacitor-Less Six-Switch Converter

2021 ◽  
Vol 11 (13) ◽  
pp. 5901
Author(s):  
Qingyang Tan ◽  
Liangzong He
Keyword(s):  
Energy Storage ◽  
Minimum Energy ◽  
Electrolytic Capacitor ◽  
Storage Capacitor ◽  
System Efficiency ◽  
Switching Cycle ◽  
Modeling Analysis ◽  
Fast Charging ◽  
Time Average ◽  
System Life

An improved modulation strategy based on minimum energy storage for DC-link capacitance reduction in a six-switch AC-AC converter is proposed. The proposed modulation strategy enables the energy on the capacitor to accumulate and release twice each in a complete switching cycle, achieving the effect of “fast charging and discharging”. Meanwhile, the inversion and rectification are modulated synchronously. Hence, there is minimum energy stored in the DC-link capacitor. Then, the time average modeling analysis is presented to take insight analysis. When there is the same voltage ripples constraint on the DC side for the conventional and improved modulation strategies, the six-switch converter under the improved modulation strategy has the much less capacitance value of the storage capacitor and even realizes non-electrolytic capacitance. Therefore, improving the system efficiency, power density, and output waveform quality and extending the system life can be achieved. The operation principle and modulation strategy are discussed in detail. Finally, the simulation model and experimental prototype are built to verify effectiveness of the topology and correctness of the proposed six-switch AC-AC converter modulation strategy.

Design and preparation of three-dimensional MnO/N-doped carbon nanocomposites based on waste biomass for high storage and ultra-fast transfer of lithium ions

2018 ◽  
Vol 6 (40) ◽  
pp. 19479-19487 ◽  
Author(s):  
Qiaoxia Feng ◽  
Huanxin Li ◽  
Zhong Tan ◽  
Zhongyuan Huang ◽  
Lanlan Jiang ◽  
...  
Keyword(s):  
Energy Storage ◽  
Three Dimensional ◽  
Waste Biomass ◽  
Energy Storage Devices ◽  
Lithium Ions ◽  
Carbon Nanocomposites ◽  
Storage Devices ◽  
Fast Charging ◽  
Increasing Demand ◽  
High Storage

Batteries with fast charging capability are urgently needed to meet the rapidly increasing demand for energy storage devices.

Preparation of BaTiO3/low melting glass core–shell nanoparticles for energy storage capacitor applications

2014 ◽  
Vol 2 (42) ◽  
pp. 18087-18096 ◽  
Author(s):  
Xiaofeng Su ◽  
Brian C. Riggs ◽  
Minoru Tomozawa ◽  
J. Keith Nelson ◽  
Douglas B. Chrisey
Keyword(s):  
Energy Storage ◽  
High Energy ◽  
Storage Capacitor ◽  
Core Shell ◽  
Material System ◽  
Shell Nanoparticles ◽  
Melting Glass ◽  
Energy Storage Capacitor ◽  
Mixing Method ◽  
Core Shell Nanoparticles

A core–shell nano-scale mixing method is applied to fabricate highly densified BaTiO3/low melting glass nanocomposites, which appear to be a promising material system for high energy storage capacitor applications.

Unsteady CHT analysis of a solid state, sensible heat storage for PHES system

2019 ◽  
Vol 30 (6) ◽  
pp. 3199-3209 ◽  
Author(s):  
Bartosz Ziegler ◽  
Jędrzej Mosiężny ◽  
Paweł Czyżewski
Keyword(s):  
Heat Transfer ◽  
Energy Storage ◽  
Solid State ◽  
Conjugate Heat Transfer ◽  
Heat Storage ◽  
Sensible Heat ◽  
System Efficiency ◽  
Exergetic Efficiency ◽  
Key Factors ◽  
Content Type

Purpose The aim of this study is to identify key factors limiting efficiency of pumped heat energy storage systems and determine some general features of transient behavior of solid state, sensible heat storages. Moreover, it aimed at establishing a feasible approach to transient conjugate heat transfer (CHT) analyses for such applications. Design/methodology/approach A zero-dimensional analytical model is used to determine the system efficiency sensitivity to efficiency of its components. Analysis of argon gas flow in an exemplary configuration of layered bed thermal energy storage is presented. The analysis incorporates a unsteady reynolds averaged navier stokes model with conjugate heat transfer between gas and solid storage core. Findings It is established that exergetic efficiency of the heat storage is one of the key factors for the system’s overall performance. Three full cycles of storage charging and discharging having 17 h physical time in total are simulated, with calculation of exergetic efficiency for each of the cycles. From standpoint of the system efficiency, it is concluded that the presented heat storage kind has limited exergetic efficiency because of severe temperature drop at the solid–fluid interface in comparison to granular kind of heat storage devices. From the methodological standpoint, it is concluded that calculating the exergetic efficiency of the heat storage by direct computational fluid dynamics (CFD) analysis requires significant amount of walltime and computational resources. Originality/value The paper presents unconventional approach to using standard CFD tools by exploiting numerical diffusion to numerically suppress high-frequency solution oscillations. This strategy grants that the analysis, otherwise requiring impractically long computation walltime, is completed within a practical time.

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