Current Issue : January - March Volume : 2020 Issue Number : 1 Articles : 5 Articles
The shunt active power filter (SAPF) is an effective means for the modification of power \nquality. However, the compensation performance of SAPF would be deteriorated when the \nunbalanced nonlinear loads are present in the power system. To enhance the compensation \nperformance of SAPF, the adaptive frequency-based reference compensation current control \nstrategy is proposed in this paper. The proposed solution procedure can be divided into three \nstages including adaptive frequency detection, phase synchronization, and adaptive compensation. \nWith the tracking of power system frequency, the phase synchronization for the SAPF \ncompensation can be effectively modified under the power variation of unbalanced nonlinear \nloads. Based on the correct synchronization phase angle, the reference compensation current of \nSAPF can be accurately obtained with the adaptive linear neural network (ALNN) in the stage of \nadaptive compensation. In addition, the direct current (DC)-link voltage of SAPF can also be \neffectively regulated to maintain the compensation performance. To verify the effectiveness of the \nproposed adaptive frequency-based reference compensation current control strategy, the \ncomprehensive case studies implemented with the hardware-in-the-loop (HIL) mechanism are \nperformed to examine the compliance with the specification limits of IEEE Standard 519-2014. The \nexperimental results reveal that the performance of proposed SAPF control strategy is superior to \nthat of the traditional instantaneous reactive power compensation control technique (p-q method) \nand sliding discrete Fourier transform (DFT)....
Exhaust gases from thermal power plants have the highest amount of carbon dioxide\n(CO2), presenting an environmental problem related to a severe impact on ecosystems. Extensively,\nthe reduction of CO2 from thermal power plants has been considered with the aid of microalgae as a\ncost-effective, sustainable solution, and efficient biological means for recycling of CO2. Microalgae can\nefficiently uptake CO2 and nutrients resulting in high generation of biomass and which can be\nprocessed into different valuable products. In this study, we have taken Nephroselmis sp. KGE8,\nAcutodesmus obliquus KGE 17 and Acutodesmus obliquus KGE32 microalgae, which are isolated from\nacid mine drainage and cultivated in a photobiological incubator on a batch scale, and also confirmed\nthat continuous culture was possible on pilot scale for biofuel production. We also evaluated the\ncontinuous culture productivity of each cultivate-harvest cycle in the pilot scale. The biomass of the\ncultivated microalgae was also evaluated for its availability....
In this paper, a steady-state matrix analysis method is introduced to analyze the output\ncharacteristics of the class-E power amplifier used in a wireless power transfer (WPT) system, which\ntakes the inductance resistance, on-resistance and leakage current of metal-oxide-semiconductor\nfield effect transistor (MOSFET) into account so that the results can be closer to the actual value.\nOn this basis, the parameters of the class-E power amplifier are optimized, and the output power is\nimproved under the premise of keeping the efficiency unchanged. Finally, the output characteristics\nof the amplifier before and after optimization are compared by an experiment, while the B-field\nstrength around the WPT system is studied through simulation. The experimental results verify the\ncorrectness and feasibility of the optimization method based on steady-state matrix analysis....
Traditional hierarchical control of the microgrid does not consider the energy storage status\nof a distributed hybrid energy storage system. This leads to the inconsistency of the remaining\ncapacity of the energy storage system in the process of system operation, which is not conducive to\nthe safe and stable operation of the system. In this paper, an improved hierarchical control strategy is\nproposed: the first allocation layer completes the allocation between the distribution energy storage\nsystems considering the state of hybrid energy storage systems, and the second allocation layer\nrealizes the allocation within the hybrid energy storage systems based on variable time constant\nlow-pass filtering. Considering the extreme conditions of energy storage systems, the transfer current\nis introduced in the second allocation process. The SOC (stage of charge) of the supercapacitor\nis between 40% and 60%, which ensures that the supercapacitor has enough margin to respond\nto the power demand. An example of a 300 MW photovoltaic microgrid system in a certain area\nis analyzed. Compared with the traditional hierarchical control, the proposed control strategy\ncan reduce the SOC change of a hybrid energy storage system by 9% under the same conditions,\nand make the supercapacitor active after power stabilization, which is helpful to the stable operation\nof the microgrid....
Sensitive volume thickness for silicon on insulator (SOI) devices has scaled to the point\nthat energy loss straggling cannot be ignored within the development of the manufacturing process.\nIn this study, irradiation experiments and Geant4 simulation were carried out to explore the influence\nof energy loss straggling on single event upsets (SEUs) caused by sub-8 MeV proton direct ionization.\nWe took a 28 nm fully-depleted SOI static random-access memory (SRAM) as the research target.\nAccording to our results, the depositing energy spectrum formed by monoenergetic low-energy\nprotons that penetrated through the sensitive volume of the target SRAM was extremely broadened.\nWe concluded that the SEUs we observed in this article were attributed to energy loss straggling.\nTherefore, it is sensible to take the new mechanism into consideration when predicting proton-induced\nSEUs for modern nanometer SOI circuits, instead of the traditional linear energy transfer (LET) method....
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