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- anharmonic Bloch oscillations
- coupled mode method
- array of waveguides
- active harmonic filter
- Multifunctional VSC
- unity power factor operation
- power quality improvement
- grid-connected SPV system
- renewable energy sources
- Optoelectronic Information Science and Engineering
- Electrical Engineering and Automation
- Shevchenko Pridnestrovskii State University
- Malaviya National Institute of Technology
- Academy of Sciences of Moldova
- IIITD&M Kancheepuram
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[IEEE 2020 International Conference on Smart Technology and Applications (ICoSTA) - Surabaya, Indonesia (2020.2.20-2020.2.20)] 2020 International Conference on Smart Technology and Applications (ICoSTA) - Design Of One Phase Inverter 250 Watt Third Harmonic Injection Pulse Width Modulation Method In Mini-Grid Photovoltaic
摘要： An inverter is an electrical power device that functions to convert DC voltage to AC voltage. The design of this inverter applied the Third Harmonic Injector Pulse Width Modulation (THIPWM) method which was implanted into the Arduino Uno microcontroller inverter performance by forming the reference signal using the sum of sinusoidal (fundamental) waves with the third harmonic wave. The simulation using PSIM software indicated that with DC voltage input of 267 Volts, the THIPWM method inverter, after passing through the LC filter, AC voltage of 221 Volts could be produced, which could theoretically be implemented. The result of the implementation test showed that the system could only load up to 40 watts, because if the system was loaded with more than 40 watts, the inverter voltage source of the quadratic boost converter would decrease and could not reach 267 Volt and the measurement value of inverter output voltage, according to calculation, had a maximum error of 3.12 percent in every load change.
关键词： LC filter,THIPWM method,Inverter,Third Harmonic Injection
更新于2025-09-23 15:21:01
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[IEEE 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Agadir, Morocco (2019.11.27-2019.11.30)] 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Power Quality Improvement of A Photovoltaic Active Power Filter using A Fuzzy Hysteresis Band Current Controller
摘要： This paper investigates a Fuzzy Hysteresis Band Current Control technique (Fuzzy-HBCC) for a Photovoltaic active power ?lter connected at PCC to the AC grid and a non-linear load. This connection offers good bene?ts of producing PV power as well as ensuring the power quality enhancement. In order to demonstrate the ef?ciency of the proposed system command using Fuzzy-HBCC, Fuzzy Vdc controller and Fuzzy-MPPT controller; several simulation cases have been carried out under an online solar variation, and a variable/?xed ignition angle of the nonlinear load. The proposed Fuzzy band current control technique (Fuzzy-HBCC) is developed and compared by simulation, in a Matlab/Simulink environment, with an adaptive Hysteresis controller (adaptive-HBCC) and a ?xed Hysteresis controller (?xed-HBCC) which require mathematical model determination. The results show the robustness of the proposed Photovotaic active power ?lter system with a better dynamic response and signi?cant reduction in Total harmonic distortion levels even under a sudden variation of the nonlinear load and of solar irradiance.
关键词： photovotaic active power ?lter,fuzzy band current control technique,dynamic response,total harmonic distortion
更新于2025-09-23 15:21:01
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[Institution of Engineering and Technology 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Lecce, Italy (23-25 May 2018)] 20th Italian National Conference on Photonic Technologies (Fotonica 2018) - Second Harmonic Generation Circul Dichroism in Au Coated Gaas-based Nanowires
摘要： Nanostructures with broken symmetry can interact with circularly polarized light to mimic chiroptical (chiral-optical) effects, usually observable in chiral media. This phenomenon is known as extrinsic chirality. Second harmonic generation (SHG) is extremely sensitive to symmetry breaking, down to a single atomic monolayer and it has been extensively used as a probe of extrinsic chirality. Here we present SHG measurements of GaAs nanowires partially covered with Au, fabricated by a self-catalysed technique. The Au coated GaAs nanowires give rise to a dramatic circular dichroism in the generated second harmonic signal, compared to nanowires without coating.
关键词： plasmonic coating,extrinsic chirality,second harmonic generation,GaAs nanowires
更新于2025-09-23 15:21:01
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Beam optimization in a 25 TW femtosecond laser system for high harmonic generation
摘要： It has been demonstrated in the past that high fluxes of extreme ultraviolet (XUV) light could be obtained by driving high harmonic generation (HHG) with high energy lasers. However, the peak intensity at the focal point of a femtosecond laser with more than 100 mJ can be too high for phase-matched HHG in gases. We propose a method to optimize the spatial profile at focus by adding customized wavefront terms. An XUV pulse energy of 5.6 μJ was obtained from HHG when a larger off-focus spot of a 500 mJ Ti: Sapphire laser beam was applied in an argon gas cell.
关键词： wavefront correction,extreme ultraviolet,femtosecond laser,high harmonic generation,Ti: Sapphire laser
更新于2025-09-23 15:21:01
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Ellipticity control of high-order harmonic generation with nearly orthogonal two-color laser fields
摘要： Elliptically polarized high-order harmonics opens a path toward the study of ultrafast dynamics in circular dichroism of magnetic materials, chiral molecules, and electronic spin motion. Recently, efficient high-order harmonic generation with controllable ellipticity has attracted considerable attention in experiment and theory. Here, we experimentally demonstrate a scenario using cross-linearly-polarized two-color fields consisting of a fundamental field and its second harmonic (SH). Through adjusting the relative phase, crossing angle, and intensity ratio of the cross-linearly-polarized two-color field, we obtain ellipticity-tunable high-order harmonics, with ellipticity up to ε = 0.73. Meanwhile, the elliptically polarized high-order harmonics preserve high efficiency. Furthermore, when the intensity of the SH field is stronger than that of the fundamental field, the even order harmonics will become several times stronger than the odd order harmonics with opposite helicity.
关键词： attosecond science,high-order harmonic generation,ellipticity control,strong-field physics,two-color laser fields
更新于2025-09-23 15:21:01
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Angular dispersion enhanced prebunch for seeding ultrashort and coherent EUV and soft X-ray free-electron laser in storage rings
摘要： Prebunching is an effective technique to reduce the radiation saturation length and to improve the longitudinal coherence and output stability in storage-ring-based free-electron lasers (FELs). A novel technique is proposed which uses angular dispersion to enhance the high-harmonic bunching with very small laser-induced energy spread. This technique can effectively reduce the radiation saturation length without significantly reducing the peak power of the FEL. Numerical simulations demonstrate that this technique can be used for the femtosecond generation of 100 MW scale level, fully temporal coherent extreme-ultraviolet and soft X-ray radiation pulses through a 10 m-long undulator based on a diffraction-limited storage ring.
关键词： angular dispersion,free-electron lasers,prebunching,storage rings,high-harmonic bunching,radiation saturation length,ultrashort,extreme-ultraviolet (EUV)
更新于2025-09-23 15:21:01
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The comparison of high-order harmonic generation of H$_{2}^{+ }$ in a circularly polarized laser pulse combined with a terahertz field and with a static electric field
摘要： By solving a two-dimensional time-dependent Schr?dinger equation we investigate high-order harmonic generation (HHG) for the H+2 molecular ion in a circularly polarized laser pulse (CPLP). A comparison is made between a HHG in a CPLP combined with a terahertz (THz) field and with a static electric field. When the CPLP is combined with a static electric field, it is observed that a double-plateau structure appears, and the harmonic spectrum presents large modulation. With the CPLP with a THz field, a continuum spectrum with a spectral width of about 137 eV from 102 eV to 239 eV can be achieved. The HHG process is studied using the semi-classical three-step model and time-frequency analysis. Our studies show that only one trajectory contributes to HHG when a THz field is added. Furthermore, we present the temporal evolution of the probability density of an electron wave packet, which shows the recombination of electrons at different times.
关键词： circularly polarized laser pulse,quantum path control,high-order harmonic generation
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) - Shenyang, China (2019.11.22-2019.11.24)] 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) - Influence of Grid-connected Photovoltaic Systems on Power Quality
摘要： This paper reviews the power quality indicators and evaluation methods specified in the IEEE. Based on the experiments, the power quality problems caused by the switching of small-scale single-phase photovoltaic (PV) systems and large-scale three-phase PV power plants are analyzed. Meanwhile, under the state of PV systems input and cut-out, the influence of load switching of different properties on power quality is analyzed. Experiments show that the switching of PV systems will lead to voltage sags and impulsive transients, as well as current waveform distortion. However, the input of PV systems has a good restraint effect on voltage sags and impulsive transients caused by loads switching.
关键词： impulsive transients,voltage sags,photovoltaic systems,unbalanced,harmonic distortion,power quality
更新于2025-09-23 15:21:01
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Recent advances with electro-optic polymers
摘要： In recent years the electro-optic polymers emerged as an important branch of material science. This growth and interest is fundamentally motivated by practical application of these materials in second-order nonlinear optics and in waveguiding configuration. Indeed, these materials marry excellent optical quality of amorphous r bonded polymers with enhanced first hyperpolarizability of imbedded organic nonlinear optical molecules. Although a big progress was achieved with them, concerning particularly the science, understanding and applications, some problems remain still incompletely solved, particularly the stability of induced polar order by the application of external electric field and the molecule aggregation. In this review paper we recall techniques of thin film fabrication, poling, characterization of NLO properties and discuss more precisely problems of molecule aggregation as well as the temporal decay of polar order. A novel 3D second-order NLO chromophores, namely the [2] paracyclophanes, which may help to limit the aggregation, are proposed. We show, in particular, that this molecule can be poled in doped PMMA thin films. Practical applications of electro-optic polymers are also reviewed and discussed.
关键词： pockels effect,electro-optic polymers,electric field poling,first hyperpolarizability,second harmonic generation,[2] paracyclophane,functionalized polymers
更新于2025-09-23 15:21:01
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Modernization of the Thl-100 Laser System to Produce Powerful Terahertz Radiation
摘要： This paper presents the results of research on parameters of the THL-100 hybrid laser system of the visible spectrum with a view to modernizing it, in order to achieve the boundary parameters required for the pumping of non-linear crystals and production of the unprecedented THz radiation powers. The laser system consists of the Start-480M Ti:Sa starting complex and photodissociation XeF(C-A) amplifier with a 24 cm aperture. After modernization, the starting complex provides the spectrally limited radiation pulse of 60 fs at the first harmonic (950 nm) at energy of 25 mJ and 50 fs at the second harmonic (475 nm) at energy of 10 mJ. In the case of the positively chirped pulse with duration of 50 ps, the energy at the second harmonic is 3 mJ. When amplifying the negatively chirped radiation pulse in the XeF(C-A) amplifier at the wavelength of 475 nm with duration of 1.8 ps, the power of 40 TW is reached, and the maximum energy is 2 J. When amplifying the positively chirped pulse with duration of 50 ps, the highest energy of 3 J is achieved.
关键词： femtosecond complex,second harmonic,laser beam,hybrid laser system,gas amplifier,radiation energy
更新于2025-09-23 15:21:01