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An Indoor Photovoltaic Energy Harvester Using Time-Based MPPT and On-chip Photovoltaic Cell
摘要： Magnetostriction of grain-oriented 3% SiFe sheets was measured prior to assembly into model transformer cores. Core vibration was measured using a laser scanning vibrometer and harmonic spectra of acoustic noise were evaluated from the microphone outputs. Explanations show why no correlation exists between vibration harmonics profiles and A-weighted acoustic noise spectra. High localized vibration did not cause high noise due to phase differences in surface vibrations, and it is shown that this is the main reason why the A-weighted noise of a three-phase core can be less than that of an equivalent single-phase core. Noise from cores assembled from low magnetostriction materials was not always lowest because of the variable effect of electromagnetic forces.
关键词： electrical machine cores,magnetostriction,transformer cores,Acoustic noise,electrical steels,vibration
更新于2025-09-19 17:13:59
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Ultra-Sharp Multimode Waveguide Bends with Dual Polarizations
摘要： Hydraulic transformer can improve the transmission ef?ciency of the hydraulic system. As the manual hydraulic transformer cannot achieve automatic control and remote control in the hydraulic system, to meet this challenge, the electro-hydraulic servo plate-inclined plunger hydraulic transformer (EHHT) was proposed in this paper. First, through analyzing the principle of the EHHT, the structure of EHHT is designed based on the theoretical analysis; Secondly, the mathematical model and simulation model of output pressure were created. Finally, the fuzzy control strategy was designed and tested on the experiment bench. Both the simulated and experimental results show that the control strategy can effectively improve the pressure control performance of hydraulic transformer and the theoretical analysis is correct.
关键词： electro-hydraulic servo,fuzzy intelligent control,hydraulic transformer,Common pressure rail
更新于2025-09-19 17:13:59
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A New Analytical Method for Calculating the Cutoff Frequencies of an Eccentrically Dielectric-Loaded Circular Waveguide
摘要： Hydraulic transformer can improve the transmission ef?ciency of the hydraulic system. As the manual hydraulic transformer cannot achieve automatic control and remote control in the hydraulic system, to meet this challenge, the electro-hydraulic servo plate-inclined plunger hydraulic transformer (EHHT) was proposed in this paper. First, through analyzing the principle of the EHHT, the structure of EHHT is designed based on the theoretical analysis; Secondly, the mathematical model and simulation model of output pressure were created. Finally, the fuzzy control strategy was designed and tested on the experiment bench. Both the simulated and experimental results show that the control strategy can effectively improve the pressure control performance of hydraulic transformer and the theoretical analysis is correct.
关键词： electro-hydraulic servo,fuzzy intelligent control,hydraulic transformer,Common pressure rail
更新于2025-09-19 17:13:59
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[IEEE 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Xiamen, China (2019.12.17-2019.12.20)] 2019 Photonics & Electromagnetics Research Symposium - Fall (PIERS - Fall) - Dual-LFM Waveform Generation Based on Optical Injection to a Semiconductor Laser
摘要： Hydraulic transformer can improve the transmission ef?ciency of the hydraulic system. As the manual hydraulic transformer cannot achieve automatic control and remote control in the hydraulic system, to meet this challenge, the electro-hydraulic servo plate-inclined plunger hydraulic transformer (EHHT) was proposed in this paper. First, through analyzing the principle of the EHHT, the structure of EHHT is designed based on the theoretical analysis; Secondly, the mathematical model and simulation model of output pressure were created. Finally, the fuzzy control strategy was designed and tested on the experiment bench. Both the simulated and experimental results show that the control strategy can effectively improve the pressure control performance of hydraulic transformer and the theoretical analysis is correct.
关键词： electro-hydraulic servo,fuzzy intelligent control,hydraulic transformer,Common pressure rail
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Comparison of Ideal Transformer Method and Damping Impedance Method for PV Power-Hardware-In-The-Loop Experiments
摘要： The Ideal Transformer Method (ITM) and the Damping Impedance Method (DIM) are the most widely used techniques for connecting power equipment to a Power-Hardware-in-the-Loop simulation. Both methods have been studied for their stability and accuracy in PHIL simulations, but neither have been analyzed when the hardware is providing grid-support services with volt-var, frequency-watt, and fixed power factor functions. In this work, we experimentally validate the two methods of connecting a physical PV inverter to a PHIL system and evaluate them for dynamic stability and accuracy when operating with grid-support functions. It was found that the DIM Low Pass Lead Filter (LPF LD) method was the best under unity and negative power factor conditions, but the ITM LPF LD method was preferred under positive power factor conditions.
关键词： damping impedance method,PHIL,power hardware-in-the-loop,lead filter,PV inverter,ideal transformer method,low pass filter
更新于2025-09-19 17:13:59
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[IEEE 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Xi'an, China (2019.6.19-2019.6.21)] 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA) - Analysis and Design of a Novel Transformer-less-Inverter in Grid-Connected Photovoltaic System
摘要： The continuous urge for improvement in our standard of living has increased the consumption of electrical energy by leaps and bounds. This hike in energy consumption, draining of fossil fuels and degrading global environment has led to invention of green power generation systems. Thus, the global demand for renewable resources has led to flourishing of photovoltaic (PV) market. The enabling technology in the PV systems is the inverter, which could be either: 1) with transformer isolated or 2) without transformer non-isolated (transformer-less inverter). Recently, single phase transformer- less voltage source inverters (VSI) have been extensively used for distributed photovoltaic grid tied systems. The objective of this paper is to review a few notable topologies and propose a new topology for transformer-less photovoltaic inverter. The analysis and design of the proposed topology is verified by simulating it on PSIM. Furthermore, the simulation results are validated by testing a proof-of-concept laboratory hardware prototype rated at 250 W.
关键词： Photovoltaic (PV) systems,transformer-less,single phase inverter
更新于2025-09-16 10:30:52
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[IEEE 2019 20th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Erlagol (Altai Republic), Russia (2019.6.29-2019.7.3)] 2019 20th International Conference of Young Specialists on Micro/Nanotechnologies and Electron Devices (EDM) - Distributed Series Impedance Devices Based on Controlled Transformer
摘要： The principles of designing of distributed series transformer with (DSI) based on impedance devices adjustable transformation ratio are considered. Analytical expressions for describing electromagnetic processes in various DSI schemes are obtained. The approaches to controlling of reactive power with adjustable transformer are described. Mathematical DSI model DSI based on controlled transformer in Matlab Simulink program is proposed and evaluated.
关键词： control,Power,compensation,power electronics,transformer
更新于2025-09-16 10:30:52
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Impact of optimum power factor of PV-controlled inverter on the aging and cost-effectiveness of oil-filled transformer considering long-term characteristics
摘要： The photovoltaic (PV) system is one of the most widespread of the renewable energy generation systems that are being used to meet the continuously increasing energy demand. A proposed analytical method is used to find the optimum power factor of PV inverter (PVI) that leads to minimum aging, reduced energy losses cost of the transformer, lower payback period of PV system, and lower green houses gases (GHG) emissions due to the transformer energy losses. In this study, the thermal performance of a 630?kVA mineral oil-filled transformer is simulated in MATLAB programming language. For an association, it is mandatory to connect a PV system to the grid to minimise the transformer loading. The PV output power is used to study the long-term impact of the solar irradiance on the transformer thermal performance. Also, the long-term climatic characteristics are considered. The ambient temperature surrounding the transformer is considered all day long. The load current profile was measured all day long. The results show the aging and cost-effectiveness of the transformer and the payback period of PV system and GHG emissions are a function of PVI power factor.
关键词： transformer aging,PV inverter,photovoltaic system,power factor,cost-effectiveness,GHG emissions
更新于2025-09-16 10:30:52
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Doping effects of ZnO quantum dots on the sensitive and selective detection of acetylene for dissolved-gas analysis applications of transformer oil
摘要： We report on the doping effect on the sensing properties of ZnO quantum dots (QDs) for the detection of acetylene. We found that In-doped ZnO (IZO) QDs exhibited a better sensing performance to 10 ppm acetylene than undoped ZnO (ZO) QDs and Al-doped ZnO (AZO) QDs. The higher sensing response of IZO QDs can be attributed to a greater number of reactive sites for detecting acetylene, which is likely to originate from the increased number of oxygen vacancies, and the larger optical band gap and surface area of IZO. This is due to a higher valence dopant and a smaller particle size. The sensing properties of IZO QDs to 10 ppm acetylene was also found to be superior to previously reported acetylene sensors that are based on semiconducting metal oxides. Furthermore, we demonstrated that 10 ppm of acetylene can be selectively detected in air within ～100 s using a recently developed miniaturized gas chromatography (GC) integrated with the IZO QDs sensor. In addition, we found that the device can detect the major fault gases of hydrogen and acetylene separately within ～100 s. Our study demonstrates that the device can be utilized in the GC-based on-line dissolved gas analysis to detect small amounts of acetylene gas in transformer oil.
关键词： Acetylene gas sensor,Dissolved gas analysis,Gas chromatography,Transformer oil,Quantum dots,ZnO
更新于2025-09-16 10:30:52
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MV Power Conversion Systems Enabled by High-Voltage SiC Devices [Happenings]
摘要： The current electrical distribution system needs to adapt due to an increase in demand and requirements for a “smarter grid,” which are required because of the proliferation of distributed energy resources (DERs). Transformers form an integral part of these electrical grids, and an upgrade to handle the additional requirements that come along is imperative. Unfortunately, an upgrade in a conventional sense is not possible, so it is time to think beyond conventional transformers. Thanks to recent strides in power electronics research and the availability of high-voltage (HV) silicon carbide (SiC) power semiconductor devices, we can contemplate building a smart “solid-state transformer” to handle the demands of the smart grid. In electrical distribution systems, the transformers convert thousands of volts [medium voltage (MV)] into lower voltages that can be safely used in homes and businesses [1]. With emerging technologies in building and fabricating MV SiC-based power semiconductor devices, MV power conversion on a large-scale scenario seems feasible. While companies, such as Wolfspeed (CREE), General Electric, Infineon Technologies, Mitsubishi, and ROHM, continue to develop and improve these MV semiconductor devices, we at the FREEDM Systems Center are aiming at the application side of things to ensure a market for these power devices.
关键词： SiC devices,smart grid,solid-state transformer,MV power conversion,power conversion
更新于2025-09-16 10:30:52