155 research outputs found
Distributed Control and Advanced Modulation of Cascaded Photovoltaic-Battery Converter Systems
Distributed Control of Islanded Series PV-Battery-Hybrid Systems with Low Communication Burden
Residual Tensor Train: A Quantum-inspired Approach for Learning Multiple Multilinear Correlations
States of quantum many-body systems are defined in a high-dimensional Hilbert
space, where rich and complex interactions among subsystems can be modelled. In
machine learning, complex multiple multilinear correlations may also exist
within input features. In this paper, we present a quantum-inspired multilinear
model, named Residual Tensor Train (ResTT), to capture the multiple multilinear
correlations of features, from low to high orders, within a single model. ResTT
is able to build a robust decision boundary in a high-dimensional space for
solving fitting and classification tasks. In particular, we prove that the
fully-connected layer and the Volterra series can be taken as special cases of
ResTT. Furthermore, we derive the rule for weight initialization that
stabilizes the training of ResTT based on a mean-field analysis. We prove that
such a rule is much more relaxed than that of TT, which means ResTT can easily
address the vanishing and exploding gradient problem that exists in the
existing TT models. Numerical experiments demonstrate that ResTT outperforms
the state-of-the-art tensor network and benchmark deep learning models on MNIST
and Fashion-MNIST datasets. Moreover, ResTT achieves better performance than
other statistical methods on two practical examples with limited data which are
known to have complex feature interactions.Comment: 12 pages, 6 figure
Distributed Control of Islanded Series PV-Battery-Hybrid Systems with Low Communication Burden
CFI2P: Coarse-to-Fine Cross-Modal Correspondence Learning for Image-to-Point Cloud Registration
In the context of image-to-point cloud registration, acquiring point-to-pixel
correspondences presents a challenging task since the similarity between
individual points and pixels is ambiguous due to the visual differences in data
modalities. Nevertheless, the same object present in the two data formats can
be readily identified from the local perspective of point sets and pixel
patches. Motivated by this intuition, we propose a coarse-to-fine framework
that emphasizes the establishment of correspondences between local point sets
and pixel patches, followed by the refinement of results at both the point and
pixel levels. On a coarse scale, we mimic the classic Visual Transformer to
translate both image and point cloud into two sequences of local
representations, namely point and pixel proxies, and employ attention to
capture global and cross-modal contexts. To supervise the coarse matching, we
propose a novel projected point proportion loss, which guides to match point
sets with pixel patches where more points can be projected into. On a finer
scale, point-to-pixel correspondences are then refined from a smaller search
space (i.e., the coarsely matched sets and patches) via well-designed sampling,
attentional learning and fine matching, where sampling masks are embedded in
the last two steps to mitigate the negative effect of sampling. With the
high-quality correspondences, the registration problem is then resolved by EPnP
algorithm within RANSAC. Experimental results on large-scale outdoor benchmarks
demonstrate our superiority over existing methods
Modeling and Analysis of 2/3-Level Dual-Active-Bridge DC-DC Converters with the Five-Level Control Scheme
Analysis and Optimal Modulation for 2/3-Level DAB Converters to Minimize Current Stress With Five-Level Control
Low-Frequency Oscillation Suppression in Series Resonant Dual-Active-Bridge Converters under Fault Tolerant Operation
When an open-switch fault occurs in the inverter-side of the series resonant dual-active-bridge (SRDAB) converter, the rectified DC voltage will drop by a half. One solution to maintain the continuous power supply of the converter is to regulate the duty-cycle of the rectifier output voltage. Nevertheless, it may excite the resonance between the resonant inductors and the DC capacitors and lead to severe low-frequency oscillations, which appears as the envelope of the high-frequency current. This phenomenon may trigger the over-current protection and make the SRDAB fail to ride through the fault. In this paper, a low-frequency equivalent model is proposed for the SRDAB, enabling frequency-domain analysis of the conventional single-loop voltage control. It is revealed that the oscillation depends on the duty-cycle and control parameters, and it is not possible to suppress such oscillations by the conventional control method. Thus, a dual-loop fault tolerant control method consists of an outer voltage control-loop, an inner current envelope control-loop. Also a non-linear correction unit is proposed to suppress the oscillation. Experimental tests on a 1-kW SRDAB are performed. The test results have validated the effectiveness of the proposal in terms of oscillation suppression
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