This paper presents small-signal impedance modeling of grid-connected three-phase converters for wind and solar system stability analysis. In the proposed approach, a converter is modeled by positive-sequence negative-sequence directly in phase domain. It further demonstrated that two sequence subsystems are decoupled under most conditions can be studied independently from each other. The models verified experimental measurements their applications testbed.

AC distributed power systems (DPS) can be found in several new and emerging applications. Similar to dc systems, an ac DPS relies on electronics control realize its functions achieve the required performance. System stability quality are important issues both types of due complex system behavior resulted from active at source load side. Traditional small-signal analysis methods cannot directly applied because periodically time-varying operation trajectory. Possible solutions this problem...

Grid impedance affects the stability and control performance of grid-connected power electronic devices, such as inverters used to integrate wind solar energy. Adaptive inverters, guarantee under different grid conditions, requires online measurement performed in real time. Such can be by injecting a current perturbation from inverter into reading voltage responses. To minimize impact on operation, injection must kept small possible while producing enough that reliably measured processed...

Abstract Under the effects of complex geological and stress environments, burst hazards continue to be a major challenge for underground space utilization deep resources exploration as its occurrence can lead personnel causalities, equipment damage structural collapse. Considering path experienced by in-situ coal body, cyclic loading appears in quite various forms instance shearer cutting, overlying strata breakage, hydro-fracturing blasting, during tunnel, mining utilizing process. The...

A discrete conformality for polyhedral metrics on surfaces is introduced in this paper. It shown that each metric a compact surface conformal to constant curvature which unique up scaling. Furthermore, the can be found using finite dimensional variational principle.

This paper presents the modeling and analysis of small-signal input impedance for line-commutated rectifiers. The recently developed mapping method, which has been applied to single-phase rectifiers with sinusoidal line inputs, is generalized distorted lines as well three-phase method assumes known circuit on dc side rectifier bridge (including its output filter load), determines corresponding ac by using a current voltage function that describes operation in frequency domain. In this...

Previous chapter Next Full AccessProceedings Proceedings of the 2009 Annual ACM-SIAM Symposium on Discrete Algorithms (SODA)Constructing Laplace Operator from Point Clouds in ℝdMikhail Belkin, Jian Sun, and Yusu WangMikhail Wangpp.1031 - 1040Chapter DOI:https://doi.org/10.1137/1.9781611973068.112PDFBibTexSections ToolsAdd to favoritesExport CitationTrack CitationsEmail SectionsAboutAbstract We present an algorithm for approximating Laplace-Beltrami operator arbitrary point cloud obtained a...

This paper deals with damping of resonance between grid-connected inverters and the power grid. proposes a narrow-band digital filtering technique to resolve problem by shaping inverter output impedance at selected frequencies without affecting characteristics outside frequency range. A frequency-sampling method is used implement filter which allows direct control filter's amplitude phase response in accordance requirements. The experimental results are presented demonstrate performance...

Abstract Moisture content of rock/coal can change its mechanical properties and absorption capacities, which directly affect gas diffusivity, the stress distribution hence cause significant impacts on overall or coal extraction process. Observation water penetration process in matrix will be beneficial for understanding fluid-solid coupling mechanism hydraulic fracturing, aquifer cracking seam infusion. However, observation determination mode were hard to non-destructively achieved as is a...

As the support mechanism of space-borne antennas, space deployable antenna belongs to complex multi-closed-loop coupling mechanism, configuration design and dynamic analysis are more difficult than general parallel mechanism. In this paper, an unequal-length scissors (ULSM) is proposed by changing position internal rotational joint through a basic A hoop-rib truss (SHRTDAM) constructed replacing parabolic rib with ULSM. Kinematic SHRTDAM conducted, degree freedom (DOF) whole analyzed based...

Considering the complex flight conditions of aircraft and difficulty oil-electric hybrid system to rationally allocate energy power give full play various advantages under different conditions, an management strategy based on multi-objective model prediction is proposed optimize engine working area, minimize dynamic characteristics, optimally manage charge state storage battery. First, fuel consumption efficiency curve identification maximum likelihood method obtain optimal area engine. The...

We consider the problem of reconstructing a road network from collection path traces and provide guarantees on accuracy reconstruction under reasonable assumptions. Our algorithm can be used to process polygonal paths in plane so that shared structures (subpaths) among discovered organized allow efficient similarity queries against new query same network. This is timely problem, as GPS other location both people vehicles are becoming available large scale there real need create appropriate...

At present, in the power industry, there has always been a demand for intelligent computing and real-time feedback on edge side using embedded devices. Due to number of parameters, calculations, memory usage deep learning model, its deployment devices is severely affected. Based this, this paper proposes lightweight object detection network based coordinate attention. The YOLOv5, decouples large convolution kernels channel space, reduces parameters kernel calculation amount operations,...

Many point-based 3D detectors adopt point-feature sampling strategies to drop some points for efficient inference. These are typically based on fixed and handcrafted rules, making it difficult handle complicated scenes. Different from them, we propose a Dynamic Ball Query (DBQ) network adaptively select subset of input according the features, assign feature transform with suitable receptive field each selected point. It can be embedded into state-of-the-art trained in an end-to-end manner,...

This paper investigates rotating magnetostrictive ultrasonic transducers (RMUT) with eddy current losses to enhance the stability requirements of high-power vibration processing in defense and military industries. A nonlinear amplitude prediction model for RMUT has been developed by integrating excitation system magnetostriction magnetization phenomena based on substructure system's transmission characteristics laws. By delving into mechanism energy conversion dynamic loss systems, influence...

The guided filter is a technique for edge-aware image filtering. Because of its nice visual quality, fast speed, and ease implementation, the has witnessed various applications in real products, such as editing apps phones stereo reconstruction, been included official MATLAB OpenCV. In this note, we remind that can be simply sped up from O(N) time to O(N/s^2) subsampling ratio s. variety applications, leads speedup >10x with almost no visible degradation. We hope acceleration will improve...

In this work, we tackle the challenging problem of category-level object pose and size estimation from a single depth image. Although previous fully-supervised works have demonstrated promising performance, collecting ground-truth labels is generally time-consuming labor-intensive. Instead, propose label-free method that learns to enforce geometric consistency between category template mesh observed point cloud under self-supervision manner. Specifically, our consists three key components:...

The architecture of porous skeletons and large crack defects in thermal barrier coatings significantly influence the protective performance coatings. In this study, quartet structure generation set method was applied to fabricate with wedge-shaped pore structures. A temperature field prediction model developed through lattice Boltzmann method. results indicate that lengthening length reducing inclination angle or depth elevate peak gradient surface temperature. Specifically, near a...