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Source Reconstruction for IC Radiated Emissions Based on Magnitude-Only Near-Field Scanning

IEEE TRANSACTIONS ON ELECTROMAGNETIC COMPATIBILITY 2017年第2期59卷 557-566页

作者： Zhang, Ji Fan, Jun Missouri Univ Sci & Technol Electromagnet Compatibil Lab Rolla MO 65409 USA

Near-field scanning with phase measurement is always a challenge in practical experiments because of its complexity and lack of accuracy. Therefore, utilizing the magnitude-only information to achieve phase-retrieval and emissions source reconstruction is preferred. This paper proposes a fast and accurate algorithm that can model the emissions from ICs by generating a set of equivalent dipole elements. The process of this algorithm only requires the information of the field magnitudes on two near-field scanning planes of different heights. Unlike other conventional source reconstruction techniques (such as genetic algorithm, gradient optimization), the proposed approach iteratively performs the back-and-forth transformations among the fields and equivalent dipole elements. By optimizing the locations of the equivalent dipole array and the initial values of these dipole elements, the iteration process is capable of quickly converging to the correct electromagnetic field values, including both magnitude and phase. The fields recovered from the calculated equivalent dipole sources have been validated by comparing to the fields emitted from a practical IC source.

关键词： Equivalent dipole elements IC emissions iteration algorithm phase retrieval source reconstruction

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Wide area measurement/wide area information-based control strategy to fast relieve overloads in a self-healing power grid

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IET GENERATION TRANSMISSION & DISTRIBUTION 2014年第6期8卷 1168-1176页

作者： Jiao, Zaibin Wang, Xiaobing Gong, Heteng Xi An Jiao Tong Univ Sch Elect Engn Xian 710049 Peoples R China

Self-healing is one of the characteristics of the smart grid. A self-healing power grid can identify and react to disturbance and restore power systems with little or even no human intervention. A wide area measurement (WAM) and wide area information (WAI)-based control strategy is proposed to fast react to overloads and restore the power grid in the self-healing power grid. The basic principle is to redistribute the power flow of a contingency transmission line to other lines with unified power flow controller (UPFC). To implement the control strategy, the reverse current network and nodal analysis method, instead of the iteration algorithm and optimisation method, is applied to redistribute the power flow. The proposed WAM/WAI-based nodal analysis can relieve overloads quickly and effectively while realising the control objective accurately. Moreover, a grid simplification method is applied to further reduce computation cost. IEEE 39-bus test system-based simulation is applied to verify the proposed control strategy. The results show that the control strategy can relieve overloads effectively in about tens of milliseconds. Thus, it could be an online controller for a self-healing power grid to deal with harmful contingencies.

关键词： cost reduction iterative methods load flow control optimisation power system measurement power transmission control power transmission economics power transmission lines smart power grids wide area measurement strategy wide area information-based control strategy fast relieve overloads self-healing power grid smart grid disturbance identification power system restoration WAM-WAI-based nodal analysis power flow redistribution contingency transmission line unified power flow controller reverse current network iteration algorithm optimisation method computation cost reduction grid simplification method IEEE 39-bus test system-based simulation

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A robust parametrization method of photovoltaic modules for enhancing one-diode model accuracy under varying operating conditions

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RENEWABLE ENERGY 2021年 168卷 764-778页

作者： Li, Chenxi Yang, Yongheng Spataru, Sergiu Zhang, Kanjian Wei, Haikun Southeast Univ Sch Automat Key Lab Measurement & Control Complex Syst Engn Minist Educ Nanjing 210096 Peoples R China Zhejiang Univ Dept Elect Engn Hangzhou 310058 Peoples R China Tech Univ Denmark Dept Photon Engn Frederiksborgvej 399 DK-4000 Roskilde Denmark

Modeling the current-voltage (I-V) characteristics of photovoltaic (PV) modules is of importance for condition monitoring and fault diagnosis of PV arrays. The practicality of the one-diode model (ODM) is relying on the behaviors of parameter extraction and translation techniques. In this paper, a simple and robust dual-iteration algorithm is presented to extract the ODM parameters using only three points under limited conditions. These points can be easily obtained from both the datasheet and measurements, making the method universal and practical. Parameters under other unknown conditions are translated from the nearest acquired condition to make the proposed method applicable for various conditions. The modeling I-V curve obtained by the proposed method is in a close agreement with the field measurement, demonstrating its effectiveness to characterize the PV modules with different technologies. Moreover, three existing models are used to benchmark the accuracy of the proposed method. The comparison further confirms that the accuracy of the ODM has been enhanced especially at low irradiance using the proposed parameter translation method. Furthermore, a distance-weighted method is presented to reliably translate the parameters, whose superiority has been validated against measurements and the other four methods, thus being an effective output assessment for monitoring and diagnosis. (c) 2020 Elsevier Ltd. All rights reserved.

关键词： PV modeling Parameters extraction One-diode model iteration algorithm Distance-weighted method

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A GaN-Based Wireless Power and Information Transmission Method Using Dual-Frequency Programmed Harmonic Modulation

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IEEE ACCESS 2020年 8卷 49848-49856页

作者： Wu, Jie Li, Yuegong Jin, Nan Deng, Wei Tang, Houjun Snasel, Vaclav Zhengzhou Univ Light Ind Dept Elect Engn Zhengzhou 450002 Peoples R China Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China VSB Tech Univ Ostrava Dept Comp Sci Ostrava 70032 Czech Republic

Information transmission is often required in power transfer to implement control. In this paper, a Dual-Frequency Programmed Harmonic Modulation (DFPHM) method is proposed to transfer two frequencies carrying power and information with the single converter via a common inductive coil. The proposed method reduces the number of injection tightly coupled transformers used to transmit information, thereby simplifying the system structure and improving reliability. The performances of power and information transmission, and the method of information modulation and demodulation, as well as the principles of the control, are analyzed in detail. Then a simulation model is set up to verify the feasibility of the method. In addition, an experiment platform is established to verify that the single converter can transfer the power and information simultaneously via a common inductive coil without using tightly coupled transformers.

关键词： Harmonic analysis Switches Resonant frequency Inverters Wireless communication Frequency modulation Dual-frequency full bridge iteration algorithm programmed harmonic modulation wireless power and information transfer

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Convergence Analysis of Iterative Laplace Transform Methods for the Coupled PDEs from Regime-Switching Option Pricing

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JOURNAL OF SCIENTIFIC COMPUTING 2018年第3期75卷 1656-1674页

作者： Ma, Jingtang Zhou, Zhiqiang Southwestern Univ Finance & Econ Sch Econ Math Chengdu 611130 Wenjiang Peoples R China

This paper aims to analyze the convergence rates of the iterative Laplace transform methods for solving the coupled PDEs arising in the regime-switching option pricing. The so-called iterative Laplace transform methods are described as follows. The semi-discretization of the coupled PDEs with respect to the space variable using the finite difference methods (FDMs) gives the coupled ODE systems. The coupled ODE systems are solved by the Laplace transform methods among which an iteration algorithm is used in the computational process. Finally, the numerical contour integral method is used as the Laplace inversion to restore the solutions to the original coupled PDEs from the Laplace space. This Laplace approach is regarded as a better alternative to the traditional time-stepping method. The errors of the approach are caused by the FDM semi-discretization, the iteration algorithm and the Laplace inversion using the numerical contour integral. This paper provides the rigorous error analysis for the iterative Laplace transform methods by proving that the method has a second-order convergence rate in space and exponential-order convergence rate with respect to the number of the quadrature nodes for the Laplace inversion.

关键词： Numerical contour integral Convergence rates Option pricing Regime-switching Laplace transform iteration algorithm

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Precise prediction of forces in milling circular corners

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INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE 2015年 88卷 184-193页

作者： Han, Xiong Tang, Limin AVIC ChengDu Aircraft Ind Grp Co Ltd Chengdu 610091 Sichuan Peoples R China

Pocket corner is the most typical characters of aerospace structure components. To achieve high-quality product and stable machining operation, manufacturer constantly seek to control the cutting forces in pocket corner milling process. This paper presents the cutting force in corner milling considering the precision instantaneous achievements of tool engagement angle and undeformed chip thickness. To achieve the actual milling tool engagement angle in corner milling process, the details of tool-corner engagement relationship are analyzed considering the elements of tool trajectory, tool radius, and corner radius. The actual undeformed chip thicknesses in up and down milling operations are approached on account of the trochoid paths of adjacent teeth by a presented iteration algorithm. Error analysis shows that the presented models of tool engagement angle and undeformed chip thickness have higher precision comparing with the traditional models. Combined with the cutting force coefficients fitted by a series of slot milling tests, the predicted cutting force in milling titanium pocket with different corner structure and milling parameters are achieved, and the prediction accuracy of the model was validated experimentally and the obtained predict and the experiment results were found in good agreement. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： Circular corner milling Cutting force prediction Engagement angle Undeformed chip thickness iteration algorithm

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Existence of solutions for abstract economic equilibrium problems and algorithm

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COMPUTERS & MATHEMATICS WITH APPLICATIONS 2006年第10-11期52卷 1471-1482页

作者： Zhang, Cong-Jun Li, Jnlu Sun, Min Nanjing Univ Finance & Econ Dept Math Appl Nanjing 210003 Peoples R China Shawnee State Univ Dept Math Portsmouth OH 45662 USA

In this paper, we study a new kind of vector equilibrium problem and we proved the existence of solutions for this kind of equilibrium problem by using the section theorem and Fan KKM theorem. Then we generalize this kind of vector equilibrium problem to a more general case. Equilibrium problems with lower and upper bounds was an open problem proposed by Isac, Sehgal and Singh in 1999. ***, ***, *** and ***, Zhang Cong-jun derived some results of the equilibrium problems with lower and upper bounds under certain conditions. In this paper we derive more results of this open problem under certain conditions, constructs an iteration algorithm, and discuses the convergence of the algorithm. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： economic equilibrium problem vector equilibrium problem equilibrium problems with lower and upper bounds section theorem iteration algorithm

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Solution to dynamic economic dispatch with prohibited operating zones via MILP

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MATHEMATICAL BIOSCIENCES AND ENGINEERING 2022年第7期19卷 6455-6468页

作者： Pan, Shanshan Jian, Jinbao Yang, Linfeng Guangxi Univ Sci & Technol Sch Sci Liuzhou 545006 Peoples R China Guangxi Minzu Univ Coll Math & Phys Nanning 530006 Peoples R China Guangxi Univ Guangxi Key Lab Multimedia Commun & Network Techn Nanning 530004 Peoples R China

Dynamic economic dispatch (DED) problem considering prohibited operating zones (POZ), ramp rate constraints, transmission losses and spinning reserve constraints is a complicated non-linear problem which is difficult to solve efficiently. In this paper, a mixed integer linear programming (MILP) method is proposed to solve such a DED problem. Firstly, a novel MILP formulation for DED problem without considering the transmission losses, denoted by MILP-1, is presented by using perspective cut reformulation technique. When the transmission losses are considered, the quadratic terms in the transmission losses are replaced by their first order Taylor expansions, and then an MILP formulation for DED considering the transmission losses, denoted by MILP-2, is obtained. Based on MILP-1 and MILP-2, an MILP-iteration algorithm is proposed to solve the complicated DED problem. The effectiveness of the MILP formulation and MILP iteration algorithm are assessed by several cases and the simulation results show that both of them can solve to competitive solutions in a short time.

关键词： dynamic economic dispatch prohibited operating zones reformulation mixed integer linear programming iteration algorithm

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Computation of demagnetizing fields and particle distribution in magnetic fluid with inhomogeneous density

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JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 2012年第7期324卷 1342-1347页

作者： Pshenichnikov, A. F. Inst Continuous Media Mech Perm 614013 Russia

A new algorithm for calculating magnetic fields in a concentrated magnetic fluid with inhomogeneous density is proposed. Inhomogeneity of the fluid is caused by magnetophoresis. In this case, the diffusion and magnetostatic parts of the problem are tightly linked together and are solved jointly. The dynamic diffusion equation is solved by the finite volume method and, to calculate the magnetic field inside the fluid, an iterative process is performed in parallel. The solution to the problem is sought in Cartesian coordinates, and the computational domain is decomposed into rectangular elements. This technique eliminates the need to solve the related boundary-value problem for magnetic fields, accelerates computations and eliminates the error caused by the finite sizes of the outer region. Formulas describing the contribution of the rectangular element to the field intensity in the case of a plane problem are given. Magnetic and concentration fields inside the magnetic fluid filling a rectangular cavity generated under the action of the uniform external filed are calculated. (C) 2011 Elsevier B.V. All rights reserved.

关键词： Magnetic fluid Magnetic field Magnetophoresis Diffusion Numerical simulation Finite volume method iteration algorithm

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Energy-optimal base station density considering traffic dynamics

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ELECTRONICS LETTERS 2015年第9期51卷 722-723页

作者： Chen, Zheng Qiu, Ling Liang, Xiaowen Univ Sci & Technol China Dept Elect Engn & Informat Sci Hefei 230027 Peoples R China

Optimal base station (BS) density, to minimise network energy consumption, is studied. Contrary to previous works, both the spatial randomness of the network topology and the wireless traffic dynamics are taken into consideration. With the technology of cell discontinuous transmission, network energy consumption depends on the average transmission probability of BSs. On the basis of stochastic geometry, it is found that the BS transmission probability and BS density satisfy a nonlinear equation. To reduce overall energy consumption, an iteration algorithm that can converge to the global optimal BS density is proposed.

关键词： cellular radio iterative methods nonlinear equations probability telecommunication network topology telecommunication power management telecommunication traffic BS transmission probability DTX cell discontinuous transmission energy-optimal base station density iteration algorithm nonlinear equation wireless network energy consumption minimisation wireless network topology spatial randomness wireless traffic dynamics spatial randomness

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