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[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - An Improved Mobile Calibration Standard for Transformer Loss Measurement Systems
摘要： Existing mobile calibration standard used for on-site calibration of transformer loss measurement systems has been upgraded. Master-slave configuration of programmable power sources is replaced with the external triggering and synchronization method which ensures the system stability below 50 ppm. Resolution in phase-settings between voltage and current generation is now improved about 2-digits down to 1 m°. And, measurement results are automatically evaluated with the corrected calibration values of system components.
关键词： on-site calibration,loss measurements,Distribution and power transformers,uncertainty,low-power factor
更新于2025-09-10 09:29:36
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Structural and thermoelectric properties of Se doped In <sub/>2</sub> Te <sub/>3</sub> thin films
摘要： The Se-Te based chalcogenides exhibit novel property of Phase Change Memory (PCM) which has potential applications in electrical non-volatile memories. These materials are also suitable in thermal to electrical energy conversions and, hence, of potential interest in energy sustainability as thermoelectric devices. In this study, the Se doped In2Te3 thin films were prepared by thermal evaporation and were annealed at 250 ?C and 300 ?C in Argon gas. The X-ray diffraction spectra show that thermal annealing leads to the phase transitions in Se doped In2Te3 into binary phases of In2Se3 and In2Te3. The surface morphology of the films exhibits the grains of spherical nature. Annealing also decreases the energy band gap due to the presence of two phases. From the four probe and photoconductivity measurements, a large contrast in electrical resistance between the amorphous and crystalline states is found with a variation of a few orders of magnitude. The electrical transport properties such as the electrical resistivity, Seebeck coefficient and the power factor were measured in the temperature range from 300 K to 430 K. All the deposited and annealed thin films exhibit n-type conductivity with the Seebeck coefficient ranging from -338 μVK-1 to -510 μVK-1. An increase in thermoelectric power of 25% is observed in the 300 ?C annealed films in comparison to the as-deposited films. Moreover, the lower Se doped In2(Te0.96Se0.04)3 compound exhibits a better thermoelectric performance compared to the In2(Te0.90Se0.1)3 composition. This study shows the multifunctional nature of Se doped In2Te3 both for PCM and thermoelectric applications.
关键词： power factor,Seebeck coefficient,Phase Change Memory,X-ray diffraction,thermal evaporation,Se-Te based chalcogenides,electrical resistance,thermoelectric devices
更新于2025-09-10 09:29:36
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Thermoelectric performance of monolayer InSe improved by convergence of multivalley bands
摘要： We theoretically investigate a possibility of improving the thermoelectric performance of monolayer InSe through convergence of multivalley energy bands, in which some distinct valleys become almost degenerate. The convergence of energy bands is achieved by applying mechanical strain. We find that the thermoelectric power factor of monolayer InSe can be significantly enhanced by nearly a factor of 3 through the band convergence in both valence (p-type) and conduction (n-type) bands under a biaxial compressive stress of about 1.16 GPa. However, the maximum enhancement of the figure of merit ZT in the p-type and n-type InSe differs each other depending on how the valleys converge in each case. The optimal scenario is that the heavy valleys approach the light valleys in the band convergence, which leads to an increase in the power factor and, at the same time, a decrease in the thermal conductivity of an electron. This optimal condition can be obtained in the strained n-type InSe that gives the largest enhancement of ZT as high as 230% ZT of unstrained InSe. In contrast, the enhancement of ZT in the strained p-type InSe, which exhibits opposite valley convergence (light valleys joining heavy ones), gives only 26% ZT of unstrained InSe.
关键词： mechanical strain,thermoelectric performance,power factor,figure of merit,multivalley bands,monolayer InSe
更新于2025-09-10 09:29:36
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Ultrafast Fabrication of Thermoelectric Films by Pulsed Light Sintering of Colloidal Nanoparticles on Flexible and Rigid Substrates
摘要： Sintered thermoelectric (TE) nanoparticle films are known to have a high figure-of-merit ZT factor and are considered for waste heat recovery and heating and cooling applications. The conventional process of thermal sintering of TE nanoparticles requires an inert environment and long heating times, and cannot be used on polymer substrates due to the requirements of the process (e.g., heating up to 400 °C). In this communication, the authors demonstrate for the first time the use of an intense flash of UV light from a Xenon lamp to sinter TE nanoparticles within milliseconds under ambient conditions on flexible polymer as well as glass substrates to create functional TE films. Photonic sintering is used to fabricate Bismuth Telluride thermoelectric films with a conductivity of 3200 S m?1 (a 5–6 orders of magnitude increase over unsintered films) and a peak power factor of 30 mW m?1 K?2. Modeling is used to gain an insight into the physical processes occurring during photonic sintering process and identify the critical parameters controlling the process. This work opens-up an exciting possibility of extremely rapid fabrication of TE generators under ambient conditions on a variety of flexible and rigid substrates.
关键词： power factor,ZT factor,thermoelectrics,Bi-Te nanoparticles,energy harvesting,photonic sintering
更新于2025-09-09 09:28:46
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[IEEE 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Tirunelveli, India (2018.5.11-2018.5.12)] 2018 2nd International Conference on Trends in Electronics and Informatics (ICOEI) - Power Quality Analysis & Characterization of Different Types of Lamp Used for Domestic and Industrial Purpose
摘要： In past, the incandescent lamp (IL) which is resistive load is used. Its power factor is unity & current is harmonic free but it consumes more power & generate heat. Last few decades compact fluorescent lamp (CFL) is widely used as it has an advantage of less power consumption & longer life. Nowadays Light Emitting Diode (LED) is used and have less energy consumption as compared to others lamp. But it has very less power factor, even if CFL & LED have a less energy consumption. It has various disadvantages such as it produces harmonic current due to use of semiconductor based devices. As harmonic current passes through impedance, it causes voltage distortion & hence degrading the overall power quality. In this paper the focus is given to the measurement of various power quality parameters such as Total Power Consumption and Total Harmonic Distortion for Current (ITHD) and Voltage (VTHD), Power Factor, Harmonics. The fluke 435 Series II Power Quality Analyzer is used for analysing different lamps used for residential, commercial, industrial purpose. This distorted current is improved as well as harmonics can be reduced by using harmonic filter. But it involves additional cost & expenses. Power Quality can be improved by adding harmonic filter with circuitry in lamp. This can lead to the improvement in Power Quality of overall power system.
关键词： Power Quality,LED,IL,harmonic distortion,CFL,power factor,Power Quality Analyzer
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC) - Kota Kinabalu, Malaysia (2018.10.7-2018.10.10)] 2018 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC) - Transformer-less Single Phase H2D4 Inverter with Voltage Controller for Grid-tied PV System
摘要： Nowadays the transformer-less photovoltaic (PV) grid connected inverter is more popular because of its higher efficiency, compact size and lower cost. The issue of leakage current is a technical challenge, which needs to be controlled carefully. Moreover, many inverter topologies have been proposed to proficient the inverter to control the reactive power to a certain point in order to maintain the power factor (PF) close to one. In case of solar PV system, voltage fluctuation and synchronization with the utility grid is the challenging issue. Therefore, in this paper a new transformer-less inverter is proposed consisting of four diodes and two IGBT switches called H2D4 topology. The proposed topology can overcome the issue of leakage current by maintaining the common mode (CM) voltage constant while maintain low total harmonic distortion (THD) and higher PF. Because of the minimum number of IGBT switches, the leakage current and the conduction loss decrease. Besides, the size of the system is also decreased. Additionally, voltage fluctuation and synchronization are controlled by a newly proposed voltage controlled closed loop system where duty ratio is controlled. The proposed topology and the existing neutral point clamped (NPC) and H6 topologies are simulated in MATLAB/Simulink software, to clarify the theoretical analysis. It is found that the voltage controller closed loop control system of H2D4 inverter topology more efficiently control the voltage fluctuation problems while maintaining a low current THD with higher efficiency and high PF as compared with the system without control topology.
关键词： Grid connection,voltage synchronization,utility grid,total harmonic distortion,transformer-less inverter,power factor,leakage current,reactive power
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Smart Grid and Clean Energy Technologies (ICSGCE) - Sg. Long, Cheras, Kajang, Malaysia (2018.5.29-2018.6.1)] 2018 International Conference on Smart Grid and Clean Energy Technologies (ICSGCE) - H2D4-Type Single Phase Transformer-Less Inverter with Reactive Power Control for Grid-tied PV System
摘要： Transformer-less inverter is popular for grid-tied photovoltaic (PV) system due to low cost, smaller size and higher efficiency. However, one of the technical challenges, which need to be handled carefully, is the issue of leakage current. Moreover, an inverter must be capable of controlling the reactive power to a certain extend to maintain the power factor (PF) close to unity. Therefore, many inverter topologies have been proposed. In this paper, a new four diodes and two IGBT switch based H2D4-type highly efficient transformer-less inverter is proposed that can handle the issue of leakage current maintaining low total harmonic distortion (THD) and higher PF where the common mode (CM) voltage is maintained constant. As a result, the leakage current deceases and the conduction loss as well as size of the system is decreased due to minimum number of IGBT switches. Furthermore, two control systems are proposed to control the reactive power with desire PF. The comparison among proposed H2D4 topology and conventional neutral point clamped (NPC) and H6 topology have been analyzed in this paper. To validate the accuracy of the theoretical analysis, the compared topologies are simulated in MATLAB/Simulink software. It is found that the PLL and PI closed loop control based H2D4 inverter topology controls the reactive power maintaining a low current THD with higher efficiency and high PF as compared to the system with only PI control based topology.
关键词： total harmonic distortion,leakage current,H2D4 topology,reactive power,transformer-less inverter,power factor,grid connected photovoltaic
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Thermally Triggered SiC MOSFET Aging Effect on Conducted EMI
摘要： In this paper, thermally triggered SiC MOSFET aging effect on SiC based boost PFC converter’s conducted EMI is investigated. Existing EMI evaluation and suppression studies are mostly based on power devices at healthy state. This study provides a comprehensive EMI evaluation at different state of health of SiC MOSFET used in continuous conduction mode (CCM) Boost PFC converter. For this purpose, SiC MOSFET samples are exposed to accelerated aging and the corresponding device degradations are triggered by thermal stresses. To study device characteristics at different state of health, devices under test (DUT) electrical parameters and switching transients are evaluated over aging to support SiC based AC/DC converter’s conducted EMI discussion. Respectively, device aging effect on differential mode (DM) noise and common mode (CM) noise changes are discussed in detail. An 800W single phase CCM Boost PFC prototype is built to evaluate both DM and CM noise in band B frequency range (150kHz~30MHz) with experimental testing results. According to the study, high frequency noise decrement is observed after SiC MOSFET is thermally aged.
关键词： thermal stress,power factor correction (PFC),Accelerated aging,SiC power MOSFET,EMI/EMC
更新于2025-09-04 15:30:14