scholarly journals Graphene-based dual-functional chiral metamirror composed of complementary 90° rotated U-shaped resonator arrays and its equivalent circuit model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Somayyeh Asgari ◽  
Tapio Fabritius

AbstractAn equivalent circuit model (ECM) using a MATLAB code to analyze a tunable two-layered graphene-based chiral dual-function metamirror, is proposed in this work. The investigated metastructure is composed of complementary U-shaped graphene resonator arrays in the terahertz (THz) region. The ECM analysis could be used for any two-layered chiral metastructure for any frequencies, containing resonators with a thickness less than λ/50. The characteristics of the proposed tunable metamirror were analyzed numerically using the finite element method (FEM) in CST Software to verify the ECM analysis. The proposed metamirror can be used in polarization-sensitive devices in the THz region with simpler biasing without a need for ion gels or similar. It works as a broadband TE and multiband (four bands) TM mirror in the 0.3–4.5 THz bandwidth with a strong linear dichroism (LD) response (up to 96%). The designed mirror is a dynamically tunable, dual-functional structure, requiring only 90° rotation of the incident electromagnetic fields to switch between broadband and multiband spectral behavior making it a promising candidate for future THz intelligent systems. The proposed ECM is in agreement with the FEM results. The ECM analysis provides a simple, fast, and effective way to understand the metamirror’s behavior and guides for the design and analysis of graphene-based chiral metastructures in the THz region.

2019 ◽  
Vol 9 (16) ◽  
pp. 3288
Author(s):  
Haichao Feng ◽  
Xu Cui ◽  
Jikai Si ◽  
Caixia Gao ◽  
Yihua Hu

In this work, a novel solid rotor induction motor with toroidal winding (N-TWSRIM) is proposed and its structure and main structural parameters are given. The operating principle is analyzed in accordance with the movement of the armature magnetic field at different times. An equivalent circuit model (ECM) of the N-TWSRIM is established based on composite multilayer theory to analyze and calculate motor performance quickly and accurately. Electromagnetic performance, which includes output torque, stator current, and power factor under different slip, is calculated with ECM, and its results are compared with those of the finite element method. A prototype of the N-TWSRIM is built and experimented on to validate the correctness of the operating principle and ECM. Experimental results on stator current and torque are consistent with the finite element and analytical results.


2012 ◽  
Vol 132 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Satoshi Maruyama ◽  
Muneki Nakada ◽  
Makoto Mita ◽  
Takuya Takahashi ◽  
Hiroyuki Fujita ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1644
Author(s):  
Qian Zhang ◽  
Huijuan Liu ◽  
Tengfei Song ◽  
Zhenyang Zhang

A novel, improved equivalent circuit model of double-sided linear induction motors (DLIMs) is proposed, which takes the skin effect and the nonzero leakage reactance of the secondary, longitudinal, and transverse end effects into consideration. Firstly, the traditional equivalent circuit with longitudinal and transverse end effects are briefly reviewed. Additionally, the correction coefficients for longitudinal and transverse end effects derived by one-dimensional analysis models are given. Secondly, correction factors for skin effect, which reflects the inhomogeneous air gap magnetic field vertically, and the secondary leakage reactance are derived by the quasi-two-dimensional analysis model. Then, the proposed equivalent circuit is presented, and the excitation reactance and secondary resistance are modified by the correction coefficients derived from the three analytical models. Finally, a three-dimensional (3D) finite element model is used to verify the proposed equivalent circuit model under varying air gap width and frequency, and the results are also compared with that of the traditional equivalent circuit models. The calculated thrust characteristics by the proposed equivalent circuit and 3D finite element model are experimentally validated under a constant voltage–frequency drive.


2021 ◽  
Vol 31 (5) ◽  
pp. 1-5
Author(s):  
Chaemin Im ◽  
Geonyoung Kim ◽  
Jeseok Bang ◽  
Kibum Choi ◽  
Soobin An ◽  
...  

2021 ◽  
Vol 11 (10) ◽  
pp. 4631
Author(s):  
Yu Chen ◽  
Xiaoqing Ji ◽  
Zhongyong Zhao

The accurate establishment of the equivalent circuit model of the synchronous machine windings’ broadband characteristics is the basis for the study of high-frequency machine problems, such as winding fault diagnosis and electromagnetic interference prediction. Therefore, this paper proposes a modeling method for synchronous machine winding based on broadband characteristics. Firstly, the single-phase high-frequency lumped parameter circuit model of synchronous machine winding is introduced, then the broadband characteristics of the port are analyzed by using the state space model, and then the equivalent circuit parameters are identified by using an optimization algorithm combined with the measured broadband impedance characteristics of port. Finally, experimental verification and comparison experiments are carried out on a 5-kW synchronous machine. The experimental results show that the proposed modeling method identifies the impedance curve of the circuit parameters with a high degree of agreement with the measured impedance curve, which indicates that the modeling method is feasible. In addition, the comparative experimental results show that, compared with the engineering exploratory calculation method, the proposed parameter identification method has stronger adaptability to the measured data and a certain robustness. Compared with the black box model, the parameters of the proposed model have a certain physical meaning, and the agreement with the actual impedance characteristic curve is higher than that of the black box model.


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