The Experts below are selected from a list of 17754 Experts worldwide ranked by ideXlab platform
Yang Chen - One of the best experts on this subject based on the ideXlab platform.
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Two-/three-coil Hybrid Topology and coil design for WPT system charging electric bicycles
IET Power Electronics, 2019Co-Authors: Yang Chen, Naijian Yang, Ruimin Dai, Ruikun Mai, Bin Yang, Shibin GaoAbstract:Wireless power transfer (WPT) for charging electric bicycles (EBs) can save people from tiresome plugging actions and avoid electrical shock hazards, especially in adverse weather. This study proposed a two-/three-coil Hybrid Topology to achieve constant current (CC) and constant voltage (CV) for charging EBs, simplifying control schemes. The system realises CC output with two-coil Topology and operates in CV mode with three-coil Topology by turning on a switch. Besides, an inductor array is used to compensate reactive power in CV mode when massive EBs are charged by one high-frequency inverter (HFI). The secondary side of the proposed Topology is compact, and the number of components and HFI can be reduced. A coil design process based on double-D-type for the three-coil system is given, with the constraint of mutual inductances among three coils and limited size. To demonstrate the validity of the proposed methods, an experimental setup is built, and the performance of the two-/three-coil Hybrid system indicates that the fluctuations of charging current and voltage are
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Two/Three-Coil Hybrid Topology for WPT Systems Charging Electric Bicycles
2019 IEEE Applied Power Electronics Conference and Exposition (APEC), 2019Co-Authors: Yang Chen, Naijian Yang, Lizhou Liu, Ruimin Dai, Ruikun MaiAbstract:Wireless power transfer (WPT) for charging electric bicycles (EBs) can save people from the tiresome plugging action and avoid electric shot hazards, especially in adverse weather. This paper proposed a two/three-coil Hybrid Topology to achieve constant current (CC) and constant voltage (CV) for charging EBs, simplifying the control schemes. The system realizes CC output with two-coil Topology, and operates in CV mode with three-coil Topology by turning on a switch. To demonstrate the validity of the proposed methods, an experimental setup was built. The performance of the two/three-coil Hybrid system indicates that the method can charge EBs with the maximum efficiency at 91.23%. Moreover, the fluctuations of charging current and voltage are less than 0.64% and 2.12% in the whole charging profile.
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Hybrid Topology with configurable charge current and charge voltage output based wpt charger for massive electric bicycles
IEEE Journal of Emerging and Selected Topics in Power Electronics, 2018Co-Authors: Yang Chen, Youyuan Zhang, Zhengyou HeAbstract:Wireless power transfer chargers for electric bicycles (EBs) have many advantages over transitional plug-in systems. However, to meet the charge requirements, the traditional charger needs a dedicated inverter to achieve constant current (CC) output or constant voltage (CV) output. A Hybrid Topology-based EB charging strategy is proposed using a single high-frequency inverter (HFI) to charge massive EBs, and one charging stand can be shared to charge EBs with various specifications of batteries. Configurable CC and CV outputs can be realized by turning on/off two ac switches without adopting sophisticated control schemes or wireless communication links. Besides, zero phase angle switching of HFI can be realized, and then the system efficiency is increased. Finally, the proposed method is verified by experiments with various charging conditions. The results show that the fluctuation margins of charging currents and charging voltages in the whole charging process are both less than 2.5% and the maximum efficiency reaches 91.90%. With the merit of the proposed approach, the reduction of construction cost and the control complexity is achieved. Thus, it might be one of the most promising solutions for charging massive EBs in some regions like China.
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A Hybrid Topology scale-free Gaussian-dynamic particle swarm optimization algorithm applied to real power loss minimization
Engineering Applications of Artificial Intelligence, 2014Co-Authors: Chuan Wang, Yancheng Liu, Youtao Zhao, Yang ChenAbstract:Abstract This paper proposes a Hybrid Topology scale-free Gaussian-dynamic particle swarm (HTSFGDPS) optimization algorithm for real power loss minimization problem of power system. The swarm population is divided into two parts: Hybrid Topology population and scale-free Topology population. The novel Hybrid Topology is mixed with fully connected Topology and ring Topology. Then, it enables the particles to have stronger exploration ability and fast convergence rate at the same time. In the scale-free part, the Topology will be gradually generated as the construction process and the optimization process progress synchronously. As a result, the Topology exhibits disassortative mixing property, which can improve the swarm population diversity. This work focuses on a new combination of swarm intelligence optimization theory and complex network theory, as well as its application to electric power system. The presented method is tested on IEEE 14-Bus and 30-Bus power system. The numerical results, compared with other stochastic search algorithms, show that HTSFGDPS could find high-quality solutions with higher convergence speed and probability.
S. Bulman - One of the best experts on this subject based on the ideXlab platform.
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A Hybrid Topology optimization algorithm for static and vibrating shell structures
International Journal for Numerical Methods in Engineering, 2002Co-Authors: F. Belblidia, S. BulmanAbstract:Structural designers are reconsidering traditional design procedures using structural optimization techniques. Although shape and sizing optimization techniques have facilitated a great improvement in the emergence of new optimum designs, they are still limited by the fact that a suitable Topology must be assumed initially. In this paper a Hybrid algorithm entitled constrained adaptive Topology optimization, or CATO is introduced. The algorithm, based on an artificial material model and an adaptive updating scheme, combines ideas from the mathematically rigorous homogenization (h) methods and the intuitive evolutionary (e) methods. The algorithm is applied to shell structures under static or free vibration situations. For the static situation, the objective is to produce the stiffest structure subject to given loading conditions, boundary conditions and material properties. For the free vibration situation, the objective is to maximize or minimize a chosen frequency. In both cases, a constraint on the structural volume/mass is applied and the optimization process is achieved by redistributing the material through the shell structure. The efficiency of the proposed algorithm is illustrated through several numerical examples of shells under either static or free vibration situations. Copyright © 2002 John Wiley & Sons, Ltd.
Bing-zhong Wang - One of the best experts on this subject based on the ideXlab platform.
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Design of High-Gain Miniaturized Patch Antenna by Hybrid Topology Optimization
2020 IEEE International Symposium on Antennas and Propagation and North American Radio Science Meeting, 2020Co-Authors: Shun-hui Zhu, Xue-song Yang, Bing-zhong Wang, Jian WangAbstract:A high-gain miniaturized patch antenna is designed by using a modified Hybrid Topology optimization (HTO) method. The HTO that combines scalar isotropic material with penalization (SIMP) and level set method (LSM), is based on gradient optimization with fast convergence speed. The performance of the optimized antenna is verified by simulation and measurement. Compared with the reference antenna, the patch size of the miniaturized antenna is reduced by 45%, while the realized gain and efficiency remain basically unchanged, achieving 6.2 dBi and 95%, respectively. The proposed antenna has the advantages of simple processing, low cost and easy integration. It can be utilized as a unit of array antennas.
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Design of MIMO Antenna Isolation Structure Based on a Hybrid Topology Optimization Method
IEEE Transactions on Antennas and Propagation, 2019Co-Authors: Xue-song Yang, Bing-zhong WangAbstract:A Hybrid Topology optimization (HTO) method is utilized to optimize the isolation structure of a multiple-input multiple-output (MIMO) antenna. The HTO method, in which the scalar isotropic material with penalization (SIMP) and the level set method (LSM) are integrated, is based on the gradient optimization method with fast convergence speed. It combines the advantages of strong Topology-searching ability of SIMP and smooth structure boundary of LSM. The proposed HTO method is adopted to optimize the isolation structure for good impedance matching, high isolation and high polarization purity of the MIMO antenna simultaneously. By setting the optimization structure as a symmetric one, the number of optimization variables is reduced by half. The optimization is validated by the full-wave simulation and the measurement. At the expected frequency of 5.8 GHz, the measured mutual coupling between the MIMO antenna elements with a center-to-center distance of 0.25λ0 is reduced by more than 24 dB, and the cross-polarization ratio reaches more than 27 dB. Furthermore, the reason for the isolation improvement is analyzed as well.
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Design of Patch Antennas with Symmetry by a Hybrid Topology Optimization Method
2019 International Conference on Microwave and Millimeter Wave Technology (ICMMT), 2019Co-Authors: Xue-song Yang, Jian Wang, Shun-hui Zhu, Bing-zhong WangAbstract:A Hybrid Topology optimization (HTO) method is used for the design of patch antennas with symmetry. The scalar isotropic material with penalization (SIMP) and the level-set method (LSM) are combined together to form the HTO. By applying the Hybrid scheme, a conical beam patch antenna and a two-element MIMO antenna are optimized. For the conical beam antenna, the Topology of the patch and the existence and location of the vias are optimized simultaneously. For the MIMO antenna, only the isolation structure is optimized. In order to decrease the optimization complexity, the symmetry of the antennas are utilized and only parts of the structures are optimized. The performances of all the antennas are verified by the simulation and measurement.
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Antenna Radiation Characteristics Optimization by a Hybrid Topological Method
IEEE Transactions on Antennas and Propagation, 2017Co-Authors: Jian Wang, Xue-song Yang, Xiao Ding, Bing-zhong WangAbstract:A Hybrid Topology optimization method that integrates material distribution and level set methods (LSMs) is proposed. The Topology of the antenna is optimized first by the material distribution method, and then, the derived structure, which has a zig-zag boundary, is further optimized by the LSM. By adopting this Hybrid strategy, the powerful Topology-searching ability of the material distribution method and the advantageous feature of producing structures with smooth and low sensitivity boundary of the LSM are fully exploited. To optimize antenna’s radiation characteristics, sensitivity analysis of the power density of the far-field is formulated. To demonstrate the capability of this Hybrid Topology optimization method and verify the sensitivity analysis formulation, three microstrip antennas with different desired polarizations, beam directions, and bandwidths are designed and tested. The measured results show that all the antennas not only achieve low reflection in the prescribed frequency band, but also give good performances in gain and polarization in the desired beam directions.
Ahmad R. Najafi - One of the best experts on this subject based on the ideXlab platform.
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Hybrid Topology/shape optimization under uncertainty for actively-cooled nature-inspired microvascular composites
Computer Methods in Applied Mechanics and Engineering, 2021Co-Authors: Reza Pejman, Vahid Keshavarzzadeh, Ahmad R. NajafiAbstract:Abstract We present a computational framework for Hybrid Topology/Shape (HyTopS) optimization of actively-cooled microvascular composites under uncertainty. We developed a novel HyTopS optimization scheme for microvascular composites which can perform the topological change during the shape optimization process. This task has been done by introducing a new set of design parameters to add/remove microchannels and change the Topology of the network. The profound advantage of the HyTopS method in contrast to a solely shape optimization approach is that the design space in HyTopS is not limited to the Topology of the initial configuration. We integrate the HyTopS optimization method with the non-intrusive polynomial chaos expansion (PCE) approach to conduct a robust and reliable design. The non-intrusive nature of the proposed method allows for almost any source of uncertainty to be incorporated virtually in the design optimization process. The PCE representations of the response metrics enable the optimizer to efficiently and precisely approximate the statistical moments, failure probabilities, and their sensitivities with respect to the design variables. We solve several numerical examples to demonstrate the advantages of using the suggested optimization scheme over deterministic optimization method for microvascular composites. The results reveal that the optimized designs obtained from performing optimization process under uncertainty outperform the optimized configurations of the deterministic optimization approach in terms of reducing the sensitivity of the design performance to the various random variables.
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Gradient-based Hybrid Topology/shape optimization of bioinspired microvascular composites
International Journal of Heat and Mass Transfer, 2019Co-Authors: Reza Pejman, Sherif H. Aboubakr, William H. Martin, Urmi Devi, Marcus Hwai Yik Tan, Jason F. Patrick, Ahmad R. NajafiAbstract:Abstract Construction of bioinspired vasculature in synthetic materials enables multi-functional performance via mass transport through internal fluidic networks. However, exact reproduction of intricate, natural microvascular architectures is nearly impossible and thus there is a need to create practical, manufacturable designs guided by multi-physics principles. Here we present a Hybrid Topology/Shape (HyTopS) optimization scheme for microvascular materials using the Interface-enriched Generalized Finite Element Method (IGFEM). This new approach, which can simultaneously perform topological changes as well as shape optimization of microvascular materials, is demonstrated in the context of thermal regulation. In the current study, we present a new feature that enables the optimizer to augment network Topology by creating/removing microchannels during the shape optimization process. This task has been accomplished by introducing a new set of design parameters, which act analogous to the penalization factor in the Solid Isotropic Material with Penalization (SIMP) method. The analytical sensitivity for the HyTopS optimization scheme has been derived and the sensitivity accuracy is verified against the finite difference method. We impose a set of geometrical constraints to account for manufacturing limitations and produce a design which is suitable for large-scale production without the need to perform post-processing on the obtained optimum. The method is validated by active-cooling experiments on vascularized carbon-fiber composites. Finally, we compare various application examples to demonstrate the advantages of the newly introduced HyTopS optimization scheme over solely shape optimization for microvascular materials.
Niels Aage - One of the best experts on this subject based on the ideXlab platform.
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Efficient Hybrid Topology and shape optimization combining implicit and explicit design representations
Structural and Multidisciplinary Optimization, 2020Co-Authors: Tuan T. Nguyen, J. Andreas Bærentzen, Ole Sigmund, Niels AageAbstract:This paper presents an interactive Hybrid Topology optimization method that (1) employs density for Topology optimization and (2) in a seamless fashion uses a Deformable Simplicial Complex for shape optimization. Omitting hole insertions during the shape optimization allows us to utilize adaptive mesh coarsening, which reduces the mesh size with up to seven times. The result is a combined method which can reduce computation time up to ten times in comparison with pure Lagrangian methods, while still producing adaptive meshes of good quality for analysis and design. Given the robustness of the method, we are able to perform Topology optimization by explicit meshing and shape optimization on a mobile device at frame rates that allow for real-time user interaction. The resulting “TopOpt Shape” app is available in the App Store for iOS devices.
