- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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The application of compound proportional resonant control strategy in multiple PV inverters system
摘要： In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.
关键词： compound proportional resonant control,Grid-connected multi-inverter,background harmonics,total harmonic distortion (THD),feed-forward control
更新于2025-09-23 15:21:01
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The effect of target thickness on the efficiency of high-order harmonics generated from laser-driven overdense plasma target
摘要： In this paper, we analytically and numerically studied the impact of the target thickness on the efficiency of laser-plasma based high-order harmonics generation (HHG). The optimal parametric region is acquired where the laser normalized amplitude a0, the target density ne and thickness d0 satisfy the relation: a0nc/ne < d0 < a0nc/2ne. In this region, the laser can partially penetrate the target, leading to efficient acceleration of the target. Meanwhile, the target is thick enough to oscillate along the rising edge of the laser without being broken, which guarantees the occurrence of HHG. Both one-dimensional and two-dimensional particle-in-cell simulation results verify our optimal target thickness theory, and a single attosecond pulse with I = 3.0 × 1020 W cm?2 is generated under the driving of 8.6 × 1020 W cm?2, which is several hundred times more intense than that from a thick target.
关键词： the Doppler effect,conversion efficiency,high-order harmonics,intense laser
更新于2025-09-23 15:19:57
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A strategy of PIa??+a??repetitive control for LCL-type photovoltaic inverters
摘要： Due to the traditional grid-connected current control method of single Proportional Integral (PI) and Repetitive Control (RC) strategies, the photovoltaic inverter output current will have a distortion problem, which can not only maintain the stability of the whole photovoltaic system, but also the current quality of the photovoltaic inverter grid-connected system is reduced in the case of high-order LCL photovoltaic inverter control system operation. So, a strategy of PI ? repetitive control in two-phase stationary frame is proposed. The introduction of the weighting coef?cient m of the PI controller branch can enhance the adjustment ability of the PI link and accelerate the responding speed to meet the dynamic characteristics of the entire operating system, while the other weighting coef?cient n on the repetitive controller branch can increase the correction capability and eliminate the steady-state error to meet system steady-state requirements. The scheme not only simpli?es the coordinate transformation and decoupling calculation process, but also improves the harmonics suppression ability of the photovoltaic inverter and reduces the total harmonic distortion rate of the grid-connected current. At the same time, with the load operation mode change, the system can also retain better stability and keep a fast dynamic response capability, and the grid current can be able to return to a stable state in one cycle. Finally, the effectiveness of theoretical analysis and the strategy is veri?ed by simulation.
关键词： Harmonics suppression,Repetitive controller,PI controller,PV inverter,Weighting coef?cient
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 26th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Hangzhou, China (2019.7.2-2019.7.5)] 2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA) - Characterization of 1122nm Laser for Laser Based Fault Isolation Applications
摘要： This paper presents one of the first studies of the harmonic impact of a significantly large photovoltaic (PV) solar farm of 20 MW in a utility distribution system. This solar farm is a constituent of the 80-MW PV solar farm in Sarnia, Ontario, which is so far the largest solar farm in Canada. The utility network is modeled in detail using the commercial grade PSCAD/EMTDC software, which is validated through load flow studies conducted by CYME software and correlated with SCADA measurements. The validated network model is used for network resonance study and harmonics impact analysis of the solar farms under different network conditions. The harmonics data instrumented for several months were provided by the transmission utility at the two solar farm units and at the main feeder substation. These data were utilized for extensive harmonic impact studies with widely different short-circuit levels and network resonance conditions. This paper presents the detailed procedure adopted for performing such harmonic impact studies. It is concluded that this large solar farm may not cause any substantial voltage distortion on the distribution network during steady-state operating conditions. However, recommendations are made for utilities to perform such studies to ensure the safe operation of critical loads.
关键词： network resonance,total harmonic distortion,solar energy,harmonics,Distribution systems,total demand distortion,photovoltaic (PV) solar system,frequency scan
更新于2025-09-23 15:19:57
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Time-dependent optimization of laser-produced molecular plasmas through high-order harmonic generation
摘要： Analysis and characterization of laser-produced plasmas (LPPs) require the advanced methods for determination of different multiparticle component formation and spreading. Time-resolved high-order harmonic generation (HHG) in spreading LPPs allows determining optimal conditions for this process. One of the most important parameters of HHG in LPP is the delay between the heating and driving pulses. We demonstrate that the optimization of delays allows achieving the maximal harmonic yields in LPP created on the surfaces of the solid targets possessing different molar masses (m). The optimal delays (t) for B4C, ZnO, GaP, GaAs, and Ag2S plasmas were determined to be approximately 200, 300, 350, 500, and 700 ns, respectively. These variations of delays correspond to the t1(m)0.5 dependence for different materials. We demonstrate the applicability of the proposed method for analysis of the resonance-enhanced harmonics in atomic and molecular plasmas (Mo and MoS2) and for studies of large perovskite aggregates as potential emitters of harmonics. This diagnostic technique can also be applied to the analysis of the presence of different nanostructures in LPPs through HHG with a high spatiotemporal resolution.
关键词： perovskite aggregates,laser-produced plasmas,molar masses,time-resolved,high-order harmonic generation,optimization,nanostructures,resonance-enhanced harmonics
更新于2025-09-19 17:13:59
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[IEEE 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Paris, France (2019.9.1-2019.9.6)] 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) - Combined UTC-PD integrated on-chip THz near field microscopy with coupled planar Goubau lines
摘要： This paper proposes a method capable of reproducing the particular operating conditions of a hot strip mill and predicting the evolution of the main electrical variables from both the characteristics of the steel to be milled and the specific features of the rolling mill. The method analyzes the load torque and the motor-speed evolution in the stands of the roughing and finishing mill drives, according to the steel to be milled. In this study, three types of carbon alloy steel are considered, thus involving dissimilar hardness characteristics. The main stands of the mill, the power network, and the filter banks have been modeled. The relationship between the grade of steel and both the electrical demand and various power quality parameters is discussed. The results can be used as a part of an expert system for the automatic estimation of the electrical demand in a hot rolling mill.
关键词： steel,hot rolling mill,Electrical demand,power system harmonics,finishing mill,roughing mill
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Tunable associative readout in self-associative Fourier holography scheme by means of fine alignment
摘要： This paper proposes a method capable of reproducing the particular operating conditions of a hot strip mill and predicting the evolution of the main electrical variables from both the characteristics of the steel to be milled and the specific features of the rolling mill. The method analyzes the load torque and the motor-speed evolution in the stands of the roughing and finishing mill drives, according to the steel to be milled. In this study, three types of carbon alloy steel are considered, thus involving dissimilar hardness characteristics. The main stands of the mill, the power network, and the filter banks have been modeled. The relationship between the grade of steel and both the electrical demand and various power quality parameters is discussed. The results can be used as a part of an expert system for the automatic estimation of the electrical demand in a hot rolling mill.
关键词： steel,hot rolling mill,Electrical demand,power system harmonics,finishing mill,roughing mill
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE International Conference on Unmanned Systems (ICUS) - Beijing, China (2019.10.17-2019.10.19)] 2019 IEEE International Conference on Unmanned Systems (ICUS) - Observability Enhancement of the Target Tracking Model Based on Infrared Semi-strapdown Seeker
摘要： A large petrochemical company installed nearly 50 000 hp of electrical submersible pumps (ESPs) at an existing midwest U.S. oil ?eld. Being equipped with adjustable-speed drives (ASDs), these ESPs introduced high levels of current harmonic dis-tortion, which resulted in 14%–19% voltage harmonic distortion at the electrical utility supply. Initially, the utility noticed the low power factor (PF) and had the oil company pay for the installation of power factor correction (PFC) capacitors on their medium-voltage supply. Once installed, the utility began to have problems with these capacitors and continued to receive complaints from other customers adjacent to the oil ?eld; thus, they enforced har-monic limits, as de?ned by IEEE Std 519, at all points of common coupling. Measurements were made with a harmonic analyzer at several locations throughout the electrical system to quantify harmonics and determine the effect the ESPs were having on the utility distribution system. Computer simulations were performed to analyze different methods of harmonic mitigation. Ultimately, passive harmonic ?lters were installed on all ESPs in phases. In addition, the PFC capacitors were permanently disconnected after determining that a power system resonance condition existed. Once all phases of the project were complete, the voltage distortion level decreased to below 5%, and PF improved to near unity without the PFC capacitors. This paper will describe the effect of harmonics on the electrical distribution system caused by ASDs, practical solutions to excessive voltage harmonic distortion, reso-nance issues with PFC capacitors, and the challenges associated with different methods of harmonic mitigation.
关键词： resonance,Adjustable-speed drives (ASDs),electrical submersible pumps (ESPs),harmonic quantities,harmonics,capacitors,harmonic ?lters,harmonic mitigation,power factor correction (PFC),harmonic distortion
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) - An Assessment of Perovskite Solar Cells for Low-Intensity-Low-Temperature (LILT) Space Missions
摘要： We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool widely used in array signal processing and finite-rate-of-innovation (FRI) sampling. The proposed algorithm can reconstruct spatial samples. For large , this sampling requirement improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,finite rate of innovation,sphere,Annihilation filter,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-19 17:13:59
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[IEEE 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Timisoara, Romania (2019.10.17-2019.10.18)] 2019 International Conference on ENERGY and ENVIRONMENT (CIEM) - Interharmonic and Harmonic Steady-State Computation of a Grid-Tied Photovoltaic System
摘要： We propose a sampling scheme that can perfectly reconstruct a collection of spikes on the sphere from samples of their lowpass-filtered observations. Central to our algorithm is a generalization of the annihilating filter method, a tool widely used in array signal processing and finite-rate-of-innovation (FRI) sampling. The proposed algorithm can reconstruct spatial samples. For large, this sampling requirement improves over previously known FRI sampling schemes on the sphere by a factor of four. We showcase the versatility of the proposed algorithm by applying it to three problems: 1) sampling diffusion processes induced by localized sources on the sphere, 2) shot noise removal, and 3) sound source localization (SSL) by a spherical microphone array. In particular, we show how SSL can be reformulated as a spherical sparse sampling problem.
关键词： sparse sampling,spherical harmonics,finite rate of innovation,sphere,Annihilation filter,diffusion sampling,shot noise removal,sound source localization
更新于2025-09-19 17:13:59